In the face of growing global freshwater scarcity, the imperative to recycle and reuse water becomes increasingly apparent across industrial, agricultural, and domestic sectors. Eliminating a range of organic pollutants in wastewater, from pesticides to industrial byproducts, presents a formidable challenge. Among the potential solutions, membrane technologies emerge as promising contenders for treating diverse organic contaminants from industrial, agricultural, and household origins. This paper explores cutting-edge membrane-based approaches, including reverse osmosis, nanofiltration, ultrafiltration, microfiltration, gas separation membranes, and pervaporation. Each technology's efficacy in removing distinct organic pollutants while producing purified water is scrutinized. This review delves into membrane fouling, discussing its influencing factors and preventative strategies. It sheds light on the merits, limitations, and prospects of these various membrane techniques, contributing to the advancement of wastewater treatment. It advocates for future research in membrane technology with a focus on fouling control and the development of energy-efficient devices. Interdisciplinary collaboration among researchers, engineers, policymakers, and industry players is vital for shaping water purification innovation. Ongoing research and collaboration position us to fulfill the promise of accessible, clean water for all.

  • Effective wastewater treatment helps to recycle and reuse water.

  • Membrane technologies are promising for treating wide organic contaminants.

  • This paper explores various advanced membrane techniques.

  • This review examines membrane fouling, including influencing factors and prevention strategies.

  • It illuminates the evolving membrane techniques, aiding the progress of wastewater treatment.

AMD

acid mine drainage system

BLM

bulk liquid membrane

CA

cellulose acetate

CNC

cellulose nanocrystal

COD

chemical oxygen demand

CTA

cellulose triacetate

DCMD

direct contact membrane distillation

DMF

dimethylformamide

DMSO

dimethyl sulfoxide

EGDMA

ethylene glycol dimethylcrylate

ELM

emulsion liquid membrane

EPS

extracellular polymeric substances

FO

forward osmosis

FOMBR

forward osmosis membrane reactor

FOwEO

forward osmosis with the function of electrochemical oxidation

FTIR

Fourier transformation infrared spectroscopy

GO

graphene oxide

IBU

Ibuprofen

LAS

linear alkylbenzene

LM

liquid membrane

MBR

membrane bioreactor

MCE

mixed cellulose ester

MDP

m-phenylenediamine

MF

microfiltration

NF

nanofiltration

NMP

N-methyl pyrrolidone

OSRO

reverse osmosis organic solvent

PA

polyamide

PAFO

pressure-assisted forward osmosis

Pd

palladium

PDMS

polydimethylsiloxane

PE

polyethylene

PEGDA

polyethylene glycol diacrylate

PEI

polyethyleneimine

PES

polyether sulfone

PK

polyketone

PV

pervaporation

PVDF

polyvinylidene

RSF

reverse salt flux

RSM

response surface methodology

RO

reverse osmosis

SA

salicylic acid

SGMD

sweep gas membrane distillation

SLM

supported liquid membrane

SRSF

specific reverse salt flux

TBP

tributyl phosphate

TDA

tridodecylamine

TDS

total dissolved solids

TFC

thin film composite

TFN

thin-film nanocomposites

TOC

total organic carbon

TrOC

trace organic compound

TSS

total suspended solids

WWTP

wastewater treatment plant

XRD

X-ray diffraction

Membrane separation technology (MST) is promising for selectively removing various organic pollutants from diverse sources through a semi-permeable membrane (Nqombolo et al. 2018; Obotey Ezugbe & Rathilal 2020; Bera et al. 2022). This technology is promising for removing a range of physical, biological, and chemical pollutants. It serves as a cost-effective and ecological wastewater treatment solution, notable for its minimal chemical usage and absence of hazardous byproducts (Jacangelo et al. 1997). Consequently, MST contributes to safeguarding public health and the environment by reducing exposure to harmful organic pollutants (Guo et al. 2019).

Selecting an appropriate membrane type, influenced by pollutant size properties and wastewater characteristics, is the primary step in MST for removing organic pollutants (Lee et al. 2016; Dai et al. 2019; Subramaniam et al. 2019; Ahmed et al. 2021; Ren et al. 2021; Rout et al. 2021). For instance, a hydrophobic membrane can effectively remove biocides and bacterial organic particles (Shahid et al. 2021). This technology provides an economical, sustainable, and efficient wastewater treatment method. It produces low sludge, is eco-friendly, scalable, adaptable to different environments, and can be integrated with other treatment methods for enhanced efficiency (Singh & Hankins 2016). It is scalable, adaptable to various environments, and can be integrated with other treatment methods to enhance removal efficiency.

Various organic pollutants, such as volatile organic compounds (VOCs) – including gaseous or liquid-phase compounds such as solvents, chemical precursors, intermediates, and petroleum compounds – can be present in wastewater. These substances are typically released from solvents, fuels, and other chemicals. Similarly, polycyclic aromatic hydrocarbons, another type of organic pollutant, form through the incomplete combustion of materials such as coal, oil, and gas. Another category of organic pollutants in wastewater is pharmaceuticals and personal care products (PPCPs). These include commonly used substances such as antibiotics, hormones, and fragrances, which enter wastewater through urine and feces (Gaur et al. 2018). PPCPs, including substances such as antibiotics, hormones, and fragrances used in daily life, can end up in wastewater through urine and feces. Pesticides, utilized in agriculture for pest and disease control, can be released into the environment via runoff, leaching, and spray drift (Wolf et al. 1991). Similarly, chlorinated solvents, used in industrial processes such as dry cleaning and metal cleaning, can enter the environment through spills, leaks, and improper disposal. Dioxins and furans, toxic byproducts of certain industrial processes such as waste incineration and chemical manufacturing, can also form during forest fires and volcanic eruptions. Proper wastewater treatment processes are essential to mitigate the adverse effects of these pollutants and protect both human health and the environment (Garcia-Rodríguez et al. 2014).

Various membrane types, including polymeric, ceramic, and composite membranes, have been evaluated for their potential to remove organic pollutants to advance membrane bioreactors (MBRs), forward osmosis (FO), and other applications (Warsinger et al. 2018). However, a comprehensive understating of the removal of organic contaminants, and their complex interactions with membrane materials and the surrounding environment is lacking (Khan & Ghoshal 2000; Farahbakhsh et al. 2004; Huang et al. 2009; Li & Visvanathan 2017; Malkoske et al. 2020). These limitations pose challenges in scaling up MST from laboratory scale to practical applications. While attempts have been made to optimize these limitations, studies conducted in diverse settings with different pollutants and conditions make it challenging to draw concrete comparisons (Lee et al. 2016; Dai et al. 2019; Subramaniam et al. 2019; Ahmed et al. 2021; Ren et al. 2021; Rout et al. 2021). The next significant challenge in this field is addressing fouling and membrane degradation to broaden the utilization of MST (Sayan et al. 2013).

Previous MST research for organic pollutant removal primarily aimed at optimizing membrane selectivity and permeability (Yang & Yang 2022), optimizing operating conditions to enhance separation efficiency (Gan et al. 2023), and understanding pollutant transport mechanisms through membranes (Ren et al. 2021). Additional studies explored the application of nanofiltration and reverse osmosis (RO) membranes to eliminate pharmaceuticals and endocrine disruptors (Riley et al. 2016). Research also delved into developing hybrid membrane systems for treating oil and gas-produced water and utilizing MBRs for industrial wastewater treatment (Riley et al. 2016).

Organic pollutants can be separated through physical, biological, or chemical processes. Physical separation can be a better option among these, especially when compared to biological degradation, which can be complex due to the potential toxicity of organic pollutants (Hanafi & Sapawe 2020). While chemical processing could be a viable alternative, offering a solution for eliminating organic and inorganic matter, color, and recalcitrant substances, it can be more expensive and falls beyond the scope of the current study (Hanafi & Sapawe 2020). This study aims to (a) evaluate the effectiveness of various membrane technologies for removing organic pollutants removal, identifying their respective advantages and limitations, (b) investigate novel pre-treatment methods to minimize fouling, enhance membrane durability, and devise strategies for improving membrane selectivity towards specific organic pollutants while maintaining high permeability. The insights gained from this review can aid researchers and engineers in developing membrane-based treatment systems, effectively eliminating organic pollutants from diverse wastewater types and contributing to environmental protection.

In recent decades, various physical separation-based MSTs have gained popularity for their advantages in water and wastewater treatment (Quist-Jensen et al. 2015). However, membrane fouling remains a challenge despite these benefits, especially with highly soluble contaminants. This chapter deals with the various physical separation MSTs, emphasizing their applications and challenges.

Microfiltration

Microfiltration (MF) is widely used in diverse industries such as pharmaceuticals, food and beverages, and semiconductors, for effective wastewater treatment (Baker 2012). This process uses filter pore sizes from 0.1 to 10 μm to eliminate pollutants such as sediment, algae, protozoa, bacteria, and proteins (Baker 2012). However, MF cannot remove tiny colloids, viruses, natural organic matter, and ions that surpass its filter retention capabilities (Howe et al. 2012).

Membrane materials in MF are selected for high mechanical strength, film-forming properties, good thermal and chemical stability, and stability over a wide pH range (Urošević & Trivunac 2020; Gul et al. 2021). Notably, a cementitious membrane effectively removes small organic pollutants, showcasing a significantly improved reaction rate constant compared to standalone ozone oxidation. Additionally, the membrane demonstrates good retention efficiency at low trans-membrane pressure (Sun et al. 2021).

MF transports suspended liquids through a sheet or tubular configuration, either parallel or perpendicular to the semi-permeable membrane (Figure S1). This process occurs at reasonably high velocities, typically in the 1–3 m/s range, and under low to moderate pressures, usually around 100–400 kPa (Green & Southard 2019). A pump, either vacuum-driven or pressure-driven, serves as the processing equipment, facilitating the liquid flow through the membrane filter. To monitor the pressure differential between the inlet and outlet streams, a differential or standard pressure gauge is frequently installed (Baker 2012).

Hybrid systems, such as integrating photocatalysis and membrane MF functionalities, reduce membrane fouling and enhance permeate flux, reporting efficiency increases of up to 10% (Ho et al. 2010; Zhao et al. 2020). Another noteworthy hybrid system combines MF with biological treatment using a mixed cellulose ester membrane, effectively resulting chemical oxygen demand (COD), total organic carbon (TOC), and phenols (Mameda et al. 2020). Furthermore, electrochemical MF is effective in removing COD, nitrogen, organic carbon, color, turbidity, and fluorophores (Mameda et al. 2020). In a separate development, a reactor combining electro-oxidation with a boron-doped diamond (BDD)/Ti anode and ceramic membrane MF was created to simultaneously remove soluble and particulate organic matter from wastewater, achieving complete COD removal and 90% removal of color and turbidity from dye wastewater (Juang et al. 2013).

MF is a potent wastewater treatment method, yet certain limitations merit consideration (Table 1). Common drawbacks include fouling, susceptibility under harsh chemical, thermal, or mechanical conditions, and relatively low durability. Moreover, MF can be costly due to three major factors: sintering temperature, membrane materials, and preparation procedures. Reducing the cost of MF is an important but challenging, as altering sintering temperature and preparation procedures may prove difficult. However, developing cost-effective raw materials for membranes can help mitigate overall costs (Singh & Purkait 2019).

Membrane bioreactor

MBR is an emerging wastewater treatment technology utilizing low-pressure membrane filtration to separate effluent from activated sludge (Jefferson et al. 2000). This approach combines a biological wastewater treatment process, such as the activated sludge process, with a membrane process, including MF or ultrafiltration (Figure S2). MBR has two primary configurations: the submerged membrane bioreactor (SMBR) and the side-stream MBR (Goswami et al. 2018). In SMBRs, the membrane is within the biological reactor and submerged in the wastewater, while in the side-stream MBR, the membrane is positioned outside the reactor as an additional step following biological treatment (Goswami et al. 2018).

In an MBR system, membranes with pore sizes between 0.035 and 0.4 μm are immersed in an aerated biological reactor (van't Oever 2005). This eliminates the need for sedimentation and filtration processes common in wastewater treatment, enabling the biological process to operate at a higher mixed liquor concentration, thereby reducing the required process tankage. The mixed liquor is typically maintained at 1.0–1.2% solids, ensuring optimal aeration and scouring around the membranes, a concentration four times higher than conventional plants (van't Oever 2005).

MBR technology, with its clear advantages over conventional methods, has clear advantages over conventional methods, and it is widely used in diverse industrial wastewater treatment applications (Table 2). Employing membrane filtration units to replace the secondary settler provides several benefits compared to traditional approaches (Lin et al. 2012). This allows effective treatment of dense wastewater, including industrial effluents and landfill leachate (Van Dijk & Roncken 1997).

Comparative studies between MBRs and conventional activated sludge systems for micropollutant degradation reveal shorter lag phases and stronger memory effects in MBRs. This suggests a quicker response to variable influent concentrations and reduced sensitivity to operational variables (De Wever et al. 2007). In an experiment focusing on removing alkyl phenol ethoxylates and their degradation products, linear alkylbenzene (LAS) sulfonates, and coconut diethanol amides, an MBR was evaluated alongside a full-scale wastewater treatment plant employing conventional activated sludge (González et al. 2007). The MBR exhibited a 94% efficiency in retaining and degrading alkyl-phenolic compounds, contrasting with the conventional activated sludge treatment's 54% removal of total nonylphenol compounds (González et al. 2007).

In an experiment exploring mixed liquor pH impact (ranging from pH 5 to 9) on trace organics removal in a submerged MBR system, results showed notable pH-related effects on ionizable trace organics, such as sulfamethoxazole, ibuprofen, ketoprofen, and diclofenac. Higher removal efficiencies were evident at pH 5 due to enhanced adsorption to activated sludge (Tadkaew et al. 2010). A subsequent study examined the degradation of 3 estrogens, 2 endocrine disruptors, and 10 pharmaceutical substances in a membrane separation bioreactor. Lower pH operation correlated with increased removal rates of acidic pharmaceutical substances, primarily attributed to heightened adsorption to sludge particles (Urase et al. 2005).

Despite the numerous advantages of MBRs over conventional methods, membrane fouling poses a significant challenge, reducing productivity and increasing maintenance and operating costs. This fouling can manifest on the membrane surface or within the membrane pores, being reversible (removable by physical washing) or irreversible (requiring chemical cleaning). Researchers highlight extracellular polymeric substances (EPS), specifically the carbohydrate fraction from the soluble microbial product (soluble EPS or biomass supernatant), as a key fouling factor in MBRs. Various strategies, such as adjusting hydrodynamics and flux, optimizing module design, and manipulating bioreactor conditions, have been proposed to control fouling (Le-Clech et al. 2006).

Reverse osmosis

RO stands out as an advanced membrane filtration method that employs a semi-permeable membrane to effectively eliminate ions, molecules, larger particles, and various dissolved and suspended contaminants, including viruses (Ouyang et al. 2019). This process relies on applying pressure to counteract osmotic pressure (Figure S3), typically ranging from 17 to 27 bars for brackish water and 52 to 69 bars for seawater. Osmotic pressure, a colligative property driven by differences in the chemical potential of the solvent (Table 3), propels this mechanism. Diffusion serves as the primary force for organic liquid separation and overcoming the formidable osmotic pressure barrier (Liu et al. 2021a).

Table 1

Some applications of microfiltration (MF) membranes

Membrane materialSource of wastewaterRemoval efficiency (%)Membrane propertiesMeritsDemeritsReferences
Electrodeposited CuO/carbon membrane (DECuO/C) Laboratory analysis RhB = 99.96; COD = 71.82; TOC = 64.29 Permeability = 823.03 L/(m2·h·bar) An approach to preparing high-performance electrocatalytic membrane Pollutants smaller than membrane pores are difficult to remove Li et al. (2020)  
Integrated biological-ceramic membrane Industries such as pulp and paper, biomass gasification, and dairy COD (pulp and paper) = 92.7; COD (biomass gasification) = 87.6; COD (dairy) = 88.2 Porosity = 44%, pore diameter = 1 μm Cost-effective approach  Goswami et al. (2019)  
PVDF Greywater COD = 98.22; LAS = 99.97; TSS = 99.99; turbidity = 99.98 Pore size = 0.1 μm; membrane area = 0.2 m2; membrane length = 50 cm The combination of multi-layer slow sand filter, MF, and ultrafiltration is more effective for LAS and suspended solids An increase in organic loading rates decreases the removal efficiency Babaei et al. (2019)  
Aluminosilicate composite Laboratory analysis Benzophenone-4 = 100; TOC = 52.67 Pore size = 1.33–0.15 μm Low cost non-toxic, good mechanical strength with a large pore-size membrane material Mechanical strength was affected by changes in different parameters Sun et al. (2021)  
Membrane materialSource of wastewaterRemoval efficiency (%)Membrane propertiesMeritsDemeritsReferences
Electrodeposited CuO/carbon membrane (DECuO/C) Laboratory analysis RhB = 99.96; COD = 71.82; TOC = 64.29 Permeability = 823.03 L/(m2·h·bar) An approach to preparing high-performance electrocatalytic membrane Pollutants smaller than membrane pores are difficult to remove Li et al. (2020)  
Integrated biological-ceramic membrane Industries such as pulp and paper, biomass gasification, and dairy COD (pulp and paper) = 92.7; COD (biomass gasification) = 87.6; COD (dairy) = 88.2 Porosity = 44%, pore diameter = 1 μm Cost-effective approach  Goswami et al. (2019)  
PVDF Greywater COD = 98.22; LAS = 99.97; TSS = 99.99; turbidity = 99.98 Pore size = 0.1 μm; membrane area = 0.2 m2; membrane length = 50 cm The combination of multi-layer slow sand filter, MF, and ultrafiltration is more effective for LAS and suspended solids An increase in organic loading rates decreases the removal efficiency Babaei et al. (2019)  
Aluminosilicate composite Laboratory analysis Benzophenone-4 = 100; TOC = 52.67 Pore size = 1.33–0.15 μm Low cost non-toxic, good mechanical strength with a large pore-size membrane material Mechanical strength was affected by changes in different parameters Sun et al. (2021)  

COD = chemical oxygen demand, LAS = linear alkylbenzene, TSS = total suspended solids, TOC = total organic carbon.

Table 2

Various applications of filtration membrane

IndustryApplicationsReferences
Food and beverage 
  • Concentration and nutritional enrichments of food products

  • Control of alcohol content of wines partial sugar removal from musts

  • Reduction of volatile acidity in wines acidification of wines

  • Removal of phenolic compounds from pomegranate juice

 
Abdel-Fatah (2018), Mulyanti & Susanto (2018), Nath et al. (2018)  
Textile and dyes 
  • Concentration

  • Permeation of organic salts

  • Removal of color

  • Removal of reactive dyes, salts, dye intermediates from wastewater

 
Abdel-Fatah (2018), Nath et al. (2018), Tavangar et al. (2019)  
Industrial process and wastewater 
  • Remove wastewater and semi-volatile organic compound from industrial process

  • Removal of degreasing agents from wastewater

  • Removal of organic pollutants such as pesticides

 
Abdel-Fatah (2018), Nath et al. (2018)  
Biotech and pharmaceuticals 
  • Separation, concentration, recovery, and production of hormones

 
Abdel-Fatah (2018), Kyburz et al. (2021)  
IndustryApplicationsReferences
Food and beverage 
  • Concentration and nutritional enrichments of food products

  • Control of alcohol content of wines partial sugar removal from musts

  • Reduction of volatile acidity in wines acidification of wines

  • Removal of phenolic compounds from pomegranate juice

 
Abdel-Fatah (2018), Mulyanti & Susanto (2018), Nath et al. (2018)  
Textile and dyes 
  • Concentration

  • Permeation of organic salts

  • Removal of color

  • Removal of reactive dyes, salts, dye intermediates from wastewater

 
Abdel-Fatah (2018), Nath et al. (2018), Tavangar et al. (2019)  
Industrial process and wastewater 
  • Remove wastewater and semi-volatile organic compound from industrial process

  • Removal of degreasing agents from wastewater

  • Removal of organic pollutants such as pesticides

 
Abdel-Fatah (2018), Nath et al. (2018)  
Biotech and pharmaceuticals 
  • Separation, concentration, recovery, and production of hormones

 
Abdel-Fatah (2018), Kyburz et al. (2021)  
Table 3

Estimated osmotic pressures for various organic solvent

Organic liquid nameEstimated osmotic pressure (bar)
NMP/Toluene 21.93 
DMF/Toluene 29.63 
DMSO/Toluene 27.99 
DMSO/Toluene 26.31 
NMP/Methanol 20.26 
Organic liquid nameEstimated osmotic pressure (bar)
NMP/Toluene 21.93 
DMF/Toluene 29.63 
DMSO/Toluene 27.99 
DMSO/Toluene 26.31 
NMP/Methanol 20.26 

NMP = N-methyl pyrrolidone, DMF = dimethylformamide, DMSO = dimethyl sulfoxide.

Table 4

Common membrane types used in nanofiltration

MembraneEfficiencyDrawbacksAdvantageReference
Polymeric membrane High Limited thermal and solvent stability 
  • Cost-effectiveness, excellent process ability, good reproducibility, and versatility

 
Lim et al. (2017)  
Cellulose-based membrane High Shorter life span, low resistance to membrane fouling, low chemical resistance, weak high-temperature resistance 
  • High strength, high specific surface area, high surface activity, non-toxic, renewable

 
Liu et al. (2021c)  
TFC membrane High Impossible for large-scale production, high cost 
  • High yield

  • Energy efficient

  • High selectivity

  • High water permeability

 
Voicu & Thakur (2021); Seah et al. (2020)  
Ceramic membrane Medium Inflexible, high investment cost, low degradability, less selectivity, high energy consumption 
  • High thermal stability

  • High chemical resistant

  • High pressure

  • Long life

  • Less contaminated

 
Liu et al. (2021c)  
Metallic oxide membrane Medium High raw material cost 
  • High water permeability

  • More effective for removing bacterial particles

 
Yang et al. (2019); Sonawane et al. (2021)  
MembraneEfficiencyDrawbacksAdvantageReference
Polymeric membrane High Limited thermal and solvent stability 
  • Cost-effectiveness, excellent process ability, good reproducibility, and versatility

 
Lim et al. (2017)  
Cellulose-based membrane High Shorter life span, low resistance to membrane fouling, low chemical resistance, weak high-temperature resistance 
  • High strength, high specific surface area, high surface activity, non-toxic, renewable

 
Liu et al. (2021c)  
TFC membrane High Impossible for large-scale production, high cost 
  • High yield

  • Energy efficient

  • High selectivity

  • High water permeability

 
Voicu & Thakur (2021); Seah et al. (2020)  
Ceramic membrane Medium Inflexible, high investment cost, low degradability, less selectivity, high energy consumption 
  • High thermal stability

  • High chemical resistant

  • High pressure

  • Long life

  • Less contaminated

 
Liu et al. (2021c)  
Metallic oxide membrane Medium High raw material cost 
  • High water permeability

  • More effective for removing bacterial particles

 
Yang et al. (2019); Sonawane et al. (2021)  

Effectively separating molecules smaller than 100 Da poses a considerable challenge, especially in pursuing an energy-efficient membrane technology for organic molecule separation. The swelling issue is significant in RO separation, particularly when dealing with organic solvents with a molecular weight below 100 Da.

In general, chemically and thermally stable cellulose is extracted from plants, while living organisms are employed in RO (Abdel-Fatah 2018). Improving the anti-fouling properties of the RO cellulose membrane involved incorporating cellulose nanocrystals into the polyamide (PA) thin-film nanocomposites membrane through in-situ polymerization of m-phenylenediamine and trimethyl chloride. This enhancement was confirmed through X-ray diffraction and Fourier transformation infrared spectroscopy analysis (Asempour et al. 2018).

For the separation of methanol and isobutanol from wastewater, a uniform cellulose membrane exhibited higher adsorption of methanol compared to isobutanol (Liu et al. 2021a). A cellulose acetate (CA)/graphene oxide (GO) nanocomposite membrane was prepared using the plane inversion method. Increasing the GO concentration up to 1 wt.% improved mechanical properties due to physiochemical interactions with the CA matrix. However, a further increase in concentration adversely affected membrane separation (Ghaseminezhad et al. 2019).

A subsequent study evaluated the removal efficiency of ultra-trace organic compounds (TrOCs) by a hollow fiber cellulose triacetate (CTA) RO membrane. The reported removal efficiency was similar to that of PA membranes, with molecular size significantly influencing the removal process (Fujioka et al. 2015).

A reverse osmosis organic solvent (OSRO) membrane was developed through interfacial polymerization on a polyketone (PK) support, achieved separation factor of 8.4 for methanol from the methanol/toluene mixture. To enhance selectivity and the separation factors, the simple heat treatment process, including initial oven heating followed by hot water heating, was applied (Liu et al. 2021b). Coating an organic-resistant substance on the PK support using a straightforward procedure resulted in an OSRO membrane with a flux of 1.0–4.0 km for non-polar liquids (alkane and toluene) and zero flux for polar liquids (alcohol) under 4 MPa (Liu et al. 2021b).

Utilizing a polyethylene (PE) support, a highly selective and mechanically durable PA thin-film composite (TFC) reverse osmosis (RO) membrane was prepared. The TCE-PE membrane exhibited superior mechanical and organic solvent resistance properties compared to commercial membranes (Park et al. 2018). Benzyl alcohol (BA) enhanced the separation performance of PA RO membranes, with BA-activated RO membranes showing higher water performance and perm selectivity than commercial membranes (Shin et al. 2019).

Silica significantly improved the properties of polyethylene glycol membranes in RO, improving both hydrophilicity and fouling resistance (Ahmad et al. 2015). After activating various concentrations of polyethylene glycol diacrylate and ethylene glycol dimethacrylate with sodium hypochlorite for 1 h, a TFC-RO membrane with high performance, and lower organic fouling was prepared (Kavaiya & Raval 2022). Addressing the challenging removal of boron from seawater, Uio-66 nanoparticles were doped into a PA thin-film nanocomposite RO membrane. This doping improved boron rejection by 11% compared to benchmark membranes (Liu et al. 2019).

While RO offers numerous advantages over other membrane techniques, it is essential to consider major drawbacks such as low permeation flux, inadequate selectivity, limited membrane durability, membrane fouling, and high equipment and operational costs (Wenten 2016). Addressing these challenges involves combining co-solvent interfacial polymerization and surface modification of substrates and active layers in RO membranes (Hailemariam et al. 2020).

Nanofiltration

Nanofiltration, an advanced membrane technology, is used for water and wastewater treatment and efficient recovery of divalent metals (Butterworth 2010). This technique utilizes a semi-permeable organic membrane under pressure to separate substances. The membranes have ultra-small pores, typically ranging from 0.1 to 10 nm, often around 1 to 2 nm in size, and with a molecular weight range of 100–5,000 Da (Nath 2017).

Nanofiltration membranes represent a versatile separation technology with properties lying between those of ultrafiltration and RO membranes (Figure S4). The separation process in nanofiltration hinges on differences in particle size and charge effects, particularly for ionic components (Mulyanti & Susanto 2018). Physical sieving emerges as a dominant mechanism for components with high molecular weight (Shon et al. 2013).

Nanofiltration membranes can be produced through polymer phase inversion, resulting in uniform asymmetric membranes, or via interfacial polymerization, where a TFC layer is added to an ultrafiltration membrane substrate (Table 4). Common materials for homogeneous asymmetric nanofiltration membranes include CA and sulfonated polysulfone. TFC nanofiltration membranes utilize cross-linked PA polymers with charged ‘pendants,’ and typical substrate materials include polysulfone, polyether sulfone (PES), polyvinylidene fluoride (PVDF), polyacrylonitrile, and polyether ether ketone.

To withstand extreme conditions such as low or high pH, high temperatures, or organic solvent environments, highly cross-linked nanofiltration membranes have been developed, featuring a slightly charged surface (Van der Merwe 1998). Key characteristics include low rejection of monovalent ions, high rejection of divalent ions, and high flux when compared to ultrafiltration and RO membranes (Marchetti et al. 2014; Mohammad et al. 2015).

In a previous study, the diffusion phenomenon was evaluated through molecular dynamic simulation of eight monosaccharides. The study found that the interaction force between the membrane and monosaccharides followed the order of sorbose > fructose > glucose > mannose > galactose, and ribose > xylose > arabinose. Additionally, the diffusion coefficient of the monosaccharides inside the membrane was found to be in the order sorbose > galactose > glucose > mannose > fructose > ribose > xylose > arabinose (Yao et al. 2018). Membrane performances are significantly influenced by operating conditions such as temperature, operating pressure, flow rate, membrane characteristics, and feed characteristics (Mulyanti & Susanto 2018).

Fouling is a significant challenge in the nanofiltration process, resulting in decreased flux and diminished cost efficiency over time. It arises from various soluble and suspended materials, including colloids, organic and inorganic substances, as well as biological components (Mohammad et al. 2015). To mitigate fouling, various physical, chemical, and hydrodynamic methods can be employed (Table 6). Notably, the acid mine drainage (AMD) system has proven effective in removing organic fouling in nanofiltration membranes, with hydrochloric acid (HCl) solutions being particularly efficient in addressing AMD-related fouling issues (Juholin et al. 2018). The utilization of graphene-based membranes and the incorporation of nano-materials shown significant promise in reducing membrane fouling in organic nanofiltration processes (Nie et al. 2021). However, further studies are needed for even more efficient and effective fouling control (Mohammad et al. 2015).

Membrane distillation

Membrane distillation (MD) is a promising, thermally driven separation technology utilizing a porous hydrophobic membrane that allows passing of vapor molecules (Figure S5). The pressure difference across the membrane surfaces serves as the driving force (A Shirazi & Kargari 2015). MD is applied in diverse fields, including desalination of both seawater and brackish water, treating radioactive waste, and removing organics and heavy metals from wastewater (Alkhudhiri et al. 2012). The MD process encompasses four configurations: direct contact membrane distillation (DCMD), air gap MD, vacuum MD, and sweep gas MD. Notably, DCMD, the most common configuration, is applied in various wastewater treatment applications targeting organic pollutants (Curcio & Drioli 2005).

Unlike conventional thermal distillation, MD operates at a lower temperature, driven by a non-exclusively thermal force. The hydrophobic membrane prevents the entry of aqueous solutions into pores, establishing liquid/vapor interfaces only under a trans-membrane pressure surpassing the membrane's liquid entry pressure. Consequently, three stages define water transport through the membrane: (1) formation of a vapor gap at the interface between the hot feed solution and the membrane, (2) transportation of the vapor phase through the microporous system, and (3) condensation of vapor at the interface between the cold side of the membrane and the permeate solution (Onsekizoglu 2012).

The MD process offers significant advantages, operating at lower temperatures than conventional methods and requiring lower hydrostatic pressure than pressure-driven technologies, enhancing cost-effectiveness. MD, a relatively new and energy-efficient process, stands out for its lower operational costs and energy consumption compared to conventional techniques such as distillation and RO (Drioli et al. 2015). The reduced energy consumption results from the lower required temperature compared to traditional distillation systems. Additionally, the process generates low-grade waste and its cost-effectiveness can be further enhanced by coupling it with alternative energy sources such as solar, geothermal, and photo energy. The lower feed temperature in MD necessitates a relatively lower driving force, which does not compromise process efficiency. Presently, MBRs coupled with MD systems have been developed for treating wastewater containing organic pollutants, addressing the limitations of MBRs. These applications extend beyond the lab scale and are implemented on a commercial scale as well.

Research on the potential application of MD systems for removing organic pollutants from diverse wastewater sources has garnered significant interest. In the case of coke wastewater, a MD system effectively produced permeates within discharge limits, allowing all refractory organics to pass the hydrophobic membrane (Ren et al. 2018). Similarly, the municipal wastewater containing TrOCs including pharmaceuticals, steroid hormones, industrial chemicals, and pesticides, underwent MD treatment. In an experiment, the MD system successfully removed all TrOCs with pH >9, while those with pH < 9 required coupling with a MBR for complete removal (Wijekoon et al. 2014). This underscores the significant impact of pH and coupling on the MD system's efficiency. Notably, recent applications of coupling the MD system with other technologies are shown in Table 5.

Table 5

Problems and preventions of various membrane technology

Membrane technologyProblemPreventionReferences
RO Precipitation of iron Backwashing cleaning process with citric acid (0.01%) as a cleaning reagent Melliti et al. (2019)  
Nanofiltration Acid mine drainage due to oxidation of sulfide minerals Chemical cleaning with 0.20% w/w hydrochloric acid (HCl) Aguiar et al. (2018)  
MD Membrane scaling by inorganic crystals and membrane fouling by organic matter in feed solutions Development of robust and super hydrophobic membrane via electro-spinning followed by electrospray to enhance membrane anti-wetting properties Liao et al. (2020)  
MBRs Biofilm formation (bio fouling) induced via cell-to-cell communication (quorum sensing) Bacterial quorum quenching along with physically (permeate) and chemically (chlorine) enhanced backwashing Weerasekara et al. (2016)  
Ultrafiltration Membrane fouling caused by effluent organic matter Ultraviolet-based oxidation pre-treatments (ultraviolet/persulfate (UV/PS) and ultraviolet/hydrogen peroxide (UV/H2O2)) Qu et al. (2021)  
Membrane technologyProblemPreventionReferences
RO Precipitation of iron Backwashing cleaning process with citric acid (0.01%) as a cleaning reagent Melliti et al. (2019)  
Nanofiltration Acid mine drainage due to oxidation of sulfide minerals Chemical cleaning with 0.20% w/w hydrochloric acid (HCl) Aguiar et al. (2018)  
MD Membrane scaling by inorganic crystals and membrane fouling by organic matter in feed solutions Development of robust and super hydrophobic membrane via electro-spinning followed by electrospray to enhance membrane anti-wetting properties Liao et al. (2020)  
MBRs Biofilm formation (bio fouling) induced via cell-to-cell communication (quorum sensing) Bacterial quorum quenching along with physically (permeate) and chemically (chlorine) enhanced backwashing Weerasekara et al. (2016)  
Ultrafiltration Membrane fouling caused by effluent organic matter Ultraviolet-based oxidation pre-treatments (ultraviolet/persulfate (UV/PS) and ultraviolet/hydrogen peroxide (UV/H2O2)) Qu et al. (2021)  
Table 6

Applications of coupling the membrane distillation (MD) system with other technologies

System integrated withPollutantsParametersResultsReferences
Photocatalysis 4-chlorophenol (4-CP) and Ag+ ion Usage of BiOBr films Degradation of 4-CP and 95% Ag+ ion removal Zou et al. (2020)  
Homogeneous catalytic ozonation TOC and salt Temperature (327 K) TOC (98.6%) and salt (100%) Zhang et al. (2016)  
Anaerobic MBR Bulk organic matter and phosphate Temperature (318 K) 100% removal efficiency compared to 76% by conventional MD Song et al. (2018)  
FO TrOCs Temperature (313 K) Greater than 99.5% removal efficiency Xie et al. (2013)  
Electrochemical oxidation VOCs Temperature (343 K) Decompose organics that MD alone could not and remove excess inorganic ions Shin et al. (2020)  
Osmotic MBR TrOCs Temperature (298 K) Greater than 90% removal efficiency Luo et al. (2017)  
Anaerobic osmotic MBR Pharmaceutically active compounds Temperature (318 K) The removal efficiency of 97.2% for dissolved organics Arcanjo et al. (2021)  
FO and electrocoagulation Organic carbon from high-salinity brines Temperature (333 K) TOC (78%) and total suspended solids (96%) Sardari et al. (2019)  
System integrated withPollutantsParametersResultsReferences
Photocatalysis 4-chlorophenol (4-CP) and Ag+ ion Usage of BiOBr films Degradation of 4-CP and 95% Ag+ ion removal Zou et al. (2020)  
Homogeneous catalytic ozonation TOC and salt Temperature (327 K) TOC (98.6%) and salt (100%) Zhang et al. (2016)  
Anaerobic MBR Bulk organic matter and phosphate Temperature (318 K) 100% removal efficiency compared to 76% by conventional MD Song et al. (2018)  
FO TrOCs Temperature (313 K) Greater than 99.5% removal efficiency Xie et al. (2013)  
Electrochemical oxidation VOCs Temperature (343 K) Decompose organics that MD alone could not and remove excess inorganic ions Shin et al. (2020)  
Osmotic MBR TrOCs Temperature (298 K) Greater than 90% removal efficiency Luo et al. (2017)  
Anaerobic osmotic MBR Pharmaceutically active compounds Temperature (318 K) The removal efficiency of 97.2% for dissolved organics Arcanjo et al. (2021)  
FO and electrocoagulation Organic carbon from high-salinity brines Temperature (333 K) TOC (78%) and total suspended solids (96%) Sardari et al. (2019)  
Table 7

Pros and cons of different membrane technologies

MethodProsConsUsed to treat
MF Effectively remove particulate matter, versatile, energy efficient, simple to operate and maintain, wide range of pore sizes Unable to remove small particles, membrane fouling, sometimes MF can be expensive (depends upon membrane and durability), complexity in changing parameters Suspended solid, bacteria and microorganism, oil and grease, phosphorus, dyes and colors, cellulosic and fibrous materials iron and manganese 
MBR High treatment efficiency, reduced footprint, flexibility in design, enhanced nutrient removal, reduced sludge production, consistent treatment performances High capital and operation costs, membrane fouling, energy intensive, complex operation and maintenance, chemical dependency, sensitive to shock loads Organic compounds, biochemical oxygen demands, total suspended solid, nutrients pathogens, oil and grease, heavy metals, pharmaceutical and personal care products, dyes and colorants, and industrial effluents 
RO Highly effective filtration, versatility, compact design, selective removal, energy efficiency, reduced environmental impact Low permeation flux, membrane fouling, inadequate selectivity, high capital and operation costs, waste generation, vulnerability to scaling Salt and minerals, heavy metals, nitrates and nitrates, organic compounds, dissolved gases, microorganisms, PPCPs, dyes and colorants, radioactive substances, TDSs 
Nanofiltration Selective filtration, high flux rates, versatility, low energy consumption, cost-effective for certain applications Limited salt rejection, membrane fouling, pressure sensitivity, variable membrane characteristics, complexity of operation Hardness, dissolved salts, nitrates and nitrites, organic compounds, colorants and dyes, boron, pharmaceutical and personal care products, heavy metals, bacteria and microbes, TDSs 
MD Low operating temperature, suitable for brine concentration, versatility, potential for renewable energy integration, compact system design, reduced scaling issues Energy intensive, membrane fouling, capital costs, complexity, limited scalability, product purity Salt and minerals, volatile organic compounds, dissolved gases, pharmaceutical and personal care products, oil and grease, heavy metals, organic compound, colorants and dyes, nutrients, radioactive substances 
PV Energy efficiency, selective separation, operational flexibility, reduced environmental impact, no azeotropic limitation, continuous operation Membrane degradation, membrane fouling, high capital costs, limited applicability, sensitive to feed composition, limited scalability Organic compounds, azeotropic mixture, alcohol and esters, pharmaceutical and personal care products, volatile inorganic compounds, oil and grease, flavor and fragrant compounds, volatile acids and bases, and selective compounds removals 
FO Low energy consumption, suitable for high-salinity feed solutions, reduced fouling, potential for use in FO-driven processes, environmental sustainability, selective permeation Draw solution challenges, limited desalination performance, membrane degradation, scaling issues, limited commercialization, complexity in system design Salinity and TDSs, heavy metals, nutrients, dyes and colorants, organic compounds, radioactive ions, oil and grease, pathogens and microbes 
LM Selective extraction, versatility, potential for high efficiency, reduced scaling issues, operational flexibility Membrane stability, limited selectivity, complexity in design, potential for emulsion issues, energy intensity, limited commercialization Metal recovery, organic compound removal, acid and base recovery, color removal, oil and grease separation, pharmaceutical wastewater treatment, radioactive waste treatment, selective ion removal 
MethodProsConsUsed to treat
MF Effectively remove particulate matter, versatile, energy efficient, simple to operate and maintain, wide range of pore sizes Unable to remove small particles, membrane fouling, sometimes MF can be expensive (depends upon membrane and durability), complexity in changing parameters Suspended solid, bacteria and microorganism, oil and grease, phosphorus, dyes and colors, cellulosic and fibrous materials iron and manganese 
MBR High treatment efficiency, reduced footprint, flexibility in design, enhanced nutrient removal, reduced sludge production, consistent treatment performances High capital and operation costs, membrane fouling, energy intensive, complex operation and maintenance, chemical dependency, sensitive to shock loads Organic compounds, biochemical oxygen demands, total suspended solid, nutrients pathogens, oil and grease, heavy metals, pharmaceutical and personal care products, dyes and colorants, and industrial effluents 
RO Highly effective filtration, versatility, compact design, selective removal, energy efficiency, reduced environmental impact Low permeation flux, membrane fouling, inadequate selectivity, high capital and operation costs, waste generation, vulnerability to scaling Salt and minerals, heavy metals, nitrates and nitrates, organic compounds, dissolved gases, microorganisms, PPCPs, dyes and colorants, radioactive substances, TDSs 
Nanofiltration Selective filtration, high flux rates, versatility, low energy consumption, cost-effective for certain applications Limited salt rejection, membrane fouling, pressure sensitivity, variable membrane characteristics, complexity of operation Hardness, dissolved salts, nitrates and nitrites, organic compounds, colorants and dyes, boron, pharmaceutical and personal care products, heavy metals, bacteria and microbes, TDSs 
MD Low operating temperature, suitable for brine concentration, versatility, potential for renewable energy integration, compact system design, reduced scaling issues Energy intensive, membrane fouling, capital costs, complexity, limited scalability, product purity Salt and minerals, volatile organic compounds, dissolved gases, pharmaceutical and personal care products, oil and grease, heavy metals, organic compound, colorants and dyes, nutrients, radioactive substances 
PV Energy efficiency, selective separation, operational flexibility, reduced environmental impact, no azeotropic limitation, continuous operation Membrane degradation, membrane fouling, high capital costs, limited applicability, sensitive to feed composition, limited scalability Organic compounds, azeotropic mixture, alcohol and esters, pharmaceutical and personal care products, volatile inorganic compounds, oil and grease, flavor and fragrant compounds, volatile acids and bases, and selective compounds removals 
FO Low energy consumption, suitable for high-salinity feed solutions, reduced fouling, potential for use in FO-driven processes, environmental sustainability, selective permeation Draw solution challenges, limited desalination performance, membrane degradation, scaling issues, limited commercialization, complexity in system design Salinity and TDSs, heavy metals, nutrients, dyes and colorants, organic compounds, radioactive ions, oil and grease, pathogens and microbes 
LM Selective extraction, versatility, potential for high efficiency, reduced scaling issues, operational flexibility Membrane stability, limited selectivity, complexity in design, potential for emulsion issues, energy intensity, limited commercialization Metal recovery, organic compound removal, acid and base recovery, color removal, oil and grease separation, pharmaceutical wastewater treatment, radioactive waste treatment, selective ion removal 

Persistent phenolic compounds such as nitrophenol, chlorophenol, and bisphenol pose environmental hazards with prolonged toxic effects on humans and animals. An effective method for their removal is the direct contact MD process, showcasing a removal efficiency exceeding 80% (Ramos et al. 2021). Additionally, the separation of oil from water, particularly from petrochemical and oil and gas industries, is achieved through various methods such as dissolved air flotation, gravity and skimming, coagulation and flocculation, and hydrocyclone techniques. However, membrane-based methods stand out for stable emulsified oily wastewater due to their advantages, such as high oil removal efficiency, low operation cost, high-quality effluents, and scalability. Implementation of the membrane treatment process requires a pre-treatment process to remove or degrade organics (Han et al. 2017). A hybrid system, coupling MD with a two-stage pre-treatment process (oil/water separation and photocatalytic organic degradation), was developed for petrochemical wastewater treatment (Table 6). Utilizing TiO2 P25 as the photocatalyst for organic compound decomposition and microorganism inactivation, the two-stage pre-treatment process achieved a remarkable 99.5% organic degradation. In the first cycle, the system exhibited a 92% oil rejection, aiming to prevent MD fouling and reduce the production of volatile organics challenging to remove with traditional methods (Li et al. 2019). Integrating photothermal active nanoparticles for localized water heating can further reduce the overall system cost (Said et al. 2020).

Pervaporation

Pervaporation (PV), a membrane separation technique combining permeation and evaporation, selectively removes volatile compounds through a permeable membrane, diffusing them to the opposite sides (Figure S6). The receiving side, equipped with a vacuum or the purge gas, facilitates the separate collection of removed compounds. Depending on the membrane's selectivity, PV finds applications in dehydrating organic solutions or removing organic contaminants from wastewater. Its extensive application spans diverse fields, including petrochemicals, food, biotechnology, pharmaceuticals, desalination, and various industrial sectors, offering higher separation capabilities and potential energy savings of 40–60% (Sekulić et al. 2005). The efficiency of the PV process hinges on the selectivity of the membrane. Recent advancements have led to investigating and developing various membrane types, including polymers, ceramics, and composites (De Bruijn et al. 2003). Polymer membranes, widely accepted, possess unique functionalities such as energy conversion, substance recognition and separation, superior permeation and flux, and efficient substance transfer.

Various polymeric membranes, including polydimethylsiloxane (PDMS), have been developed for PV separation in organic wastewater treatment. In a PV process targeting cyclohexane-containing wastewater, a PDMS membrane demonstrated a remarkable separation factor of 2,500 under operating conditions of 300 K temperature and a vacuum pressure of 10 mmHg (Rezakazemi et al. 2018). PV membrane separation is a widely used for ethanol/water separation. The integration of a PDMS membrane with the fermentation process holds promise for efficient bioethanol production. Testing the PDMS polymer membrane involved removing ethanol from water through integrated PV with batch ethanol fermentation. This system can be coupled with mechanical vapor compression for enhanced performance (Fan et al. 2017). With a separation factor ranging from 8 to 11.6, the integrated process demonstrated a high ethanol production rate on the permeate side of the membrane. This environmentally friendly and energy-saving approach holds promising prospects for long-term operation (Fu et al. 2016).

Phenolic compound mass transfer is reduced in membranes such as PDMS and urethane during PV separation of phenol-containing mixtures. To address this, alternative membranes have been devised to enhance separation efficiency and permeability. Cao et al. explored phenolic compound separation in an aqueous solution using a poly(ether-b-amide) (PEBA) PV membrane at 30–70 operating conditions. Both permeation flux and enrichment factor rose with temperature, while the enrichment factor declined with higher feed concentration (Cao et al. 2021). A PEBA membrane and a PVDF membrane were developed to recover high-purity aniline from an aqueous solution. The impact of feed concentration and temperature on separation performance was examined. At 80°C and a 3 wt.% feed concentration, the membrane exhibited outstanding performance, achieving 65.1% purity of aniline and a separation factor of 35. Scaling up this process should be considered, as it proves to be an effective method for separating high-boiling-point organic compounds from aqueous solutions (Wang et al. 2021a). When using the PDMS membrane alone, the removal efficiency of acetonitrile from the aqueous solution was only 47%. High salt in water positively influenced PV performance and the separation factor (Wang et al. 2018).

The PV process efficiently separates compounds forming azeotropes. Introduced in 1976 (Aptel et al. 1976), gained wide acceptance for azeotropic mixture separation research. A hybrid PV-distillation system was designed to reduce energy consumption in solvent recovery towers for ester/alcohol/water mixture. Compared to the traditional distillation system, the hybrid system cut annual cost by 36.03% (Li et al. 2022), proving more economical. PV-extractive distillation outperforms conventional methods for azeotropic mixtures. For challenging cyclohexane and isopropanol (IPA) azeotropes, combining distillation with PV lowers annual costs by 13.98% and CO2 emissions by 15.09% (Zhang et al. 2021). Toth et al. explored a hybrid distillation-hydrophilic PV system for ethanol separation from pharmaceutical wastewater, achieving up to 99.5 wt. % purity (Toth et al. 2018). PV also excels in integration with photocatalysis; a PVDF membrane with photocatalytic TiO2 rejected total dissolved solids (TDSs) at 2.345 mg/L and showed 98.02% color removal (Elma et al. 2022).

Various pathways, including membrane surface modification, enhance membrane separation. Introducing SiO2 particles enhances membrane surface properties, expanding membrane technology applications in organic wastewater treatment. In a composite of PDMS/PVDF with SiO2 particles, the separation factor was 2.5 times higher than a PDMS/PVDF membrane (Li et al. 2018a). Similarly, layering polyethyleneimine membranes with GO improved organic carbon rejection to 90.8%, enhancing flux rates. This suggests the promising use of GO as an incorporation material in PV membranes (Wang et al. 2021b).

Forward osmosis

FO effectively removes organic pollutants, even as small as 200 Da, such as pesticides, endocrine disruptors, and pharmaceutical molecules (Figure S7). These challenging separations for traditional membrane technologies are overcome by FO. Here, organic compounds move from the feed solution to the draw solution through a semi-permeable membrane, driven solely by the osmotic pressure gradient without external pressure (Madsen et al. 2015). FO exploits the natural tendency of water molecules to flow from low to high solute concentration across a semi-permeable membrane (Cath et al. 2006). The process involves a semi-permeable membrane separating a diluted feed solution from a concentrated draw solution, allowing water flow while blocking solutes. The osmotic pressure gradient propels water from the feed to the draw solution, concentrating the feed and diluting the draw solution (Cath et al. 2006). The diluted draw solution produces pure water, while the concentrated feed solution undergoes contaminant removal. FO operates with either natural osmotic pressure or external pressure, the latter leveraging the solute concentration difference. External pressure on the draw solution enhances the concentration gradient, increasing water flux (Cath et al. 2006).

An experiment reported, FO effectively concentrated organic matter in sewage, so the COD in the concentrate increased by 300% (Zhang et al. 2014). Another study found FO to be more effective than RO in removing organic compounds such as phenol, aniline, and nitrobenzene from wastewater (Sauchelli et al. 2018). In RO, rejection of charged TrOCs involves electrostatic interaction and size exclusion, with increased molecular weight enhancing TrOC rejection (Alturki et al. 2013).

A forward osmosis membrane bioreactor (FOMBR) effectively removed Ibuprofen (IBU) as a TrOC, achieving average removal efficiencies exceeding 96.32% (Yao et al. 2021). Processes enhancing water production include pressure-assisted forward osmosis, which increased water production by 9 and 29% under applied pressures of 2 and 4 bar, respectively (Jamil et al. 2016). Furthermore, forward osmosis with electrochemical oxidation (FOwEO) was developed to reject trace antibiotics from the wastewater. In a nearly 3-h experiment, FOwEO exhibited over 98% rejection of antibiotics (Liu et al. 2015).

Commonly used membranes for FO include CA, polysulfone, PES, polysulfone, polybenzimidazole, and PA (Alsvik & Hägg 2013). A comparison between commercial CTA and TFC PA membranes was conducted to assess the rejection of pharmaceutical compounds (carbamazepine, diclofenac, IBU, and naproxen). TFC exhibited superior overall performance, featuring high water flux, excellent pH stability, and effective rejection of all targeted compounds compared to CTA (Jin et al. 2012). Whereas, TFC membranes were superior to CTA in various aspects such as water permeability, selectivity, flux, and swelling (Sauchelli et al. 2018). TFC outperformed CTA in water permeability, selectivity, flux, and chemical cleaning efficiency (Coday et al. 2015). Evaluation of CTA and TFC membranes for fouling and performance, considering water flux, reverse salt flux, and specific reverse salt flux, revealed steady performance for CTA after 1 week, while TFC showed variations (Bell et al. 2017).

Feed solution pH and draw solute significantly impact the filtration performance and rejection of the FO process. A study of model compounds such as cyclohexane carboxylic acid (CHA), 1-adamantane acetic acid (AAA), and a refined Merichem mixture of naphthenic acid (NA) revealed pH-dependent rejection for CHA and AAA (pH 3–9), while NAs exhibited a consistent 95% rejection unaffected by pH (Zhu et al. 2018).

The FO system offers major advantages, including high water permeability, solute rejection, water recovery rates, low fouling, and energy consumption, alleviating water supply stresses and promoting power generation (Ge et al. 2013). This system is effective in concentrating radioactive liquid waste in hospitals. FO outperforms ultrafiltration and RO in rejecting both natural and radioactive iodine, with a 99% rejection rate for oil from wastewater (Yadav et al. 2020).

A significant drawback of the FO process is the inefficient removal of small neutral organic compounds. This challenge can be addressed by employing biomimetic membranes, known for selectively rejecting only three TrOCs (Madsen et al. 2015). Another drawback is membrane fouling, but combining MD with FO membranes can mitigate the deposition of organic and particulate matter on the membrane surface, reducing fouling (Xie et al. 2013). Currently, all FO processes have been conducted on a benchmark scale with limited operation time. Thus, future studies ought to explore the technology in large-scale filtration processes (Blandin et al. 2020).

Liquid membrane

Liquid membrane (LM) technology utilizes liquid surfactant membranes in a drop column, offering high effectiveness in hydrocarbon separation. In this process, droplets of a hydrocarbon-containing feed solution are injected into an aqueous solution containing surfactants (Li 1968, 1978). LM transport combines liquid–liquid extraction and membrane separation into a single continuous device. It employs an extracting reagent solution immiscible with water, flowing between two aqueous solutions or gases known as the source (or feed) phase and the receiving (or strip) phase. Typically, the source and receiving phases are aqueous, while the membrane is organic, although the opposite configuration is possible. The membrane can be made of either a polymeric or inorganic microporous support, serving as a bearer (in supported liquid membrane (SLM)) or a barrier (in many bulk liquid membrane (BLM) technologies), or omitted entirely (in emulsion liquid membrane (ELM) and layered BLM).

Solute transport in the LM primarily relies on the solution-diffusion mechanism, where solute species dissolve in the LM and diffuse across it due to a concentration gradient. The efficiency and selectivity of transport can be enhanced by introducing a mobile complexation agent (carrier) into the LM, which reacts with the desired solute to form a complex. This process, known as facilitated or carrier-mediated LM separation, is often combined with counter- or cotransport of different ions through LM to provide the energy for the uphill transport of the solute (Noble & Way 1987).

A thin gas or liquid film forms a barrier in the LM, separating two miscible liquids. Over the past two decades, LM technology has expanded its applications in chemical and pharmaceutical technology, biotechnology, food processing, and environmental engineering (San Román et al. 2010). Additionally, LM-based extractions can determine the concentration of freely dissolved pollutants on a time-weighted average basis, making them suitable for exposure risk assessment of metal ions in both environmental and biological samples (Chimuka et al. 2004). Moreover, the non-equilibrium mass transfer in the LM process offers advantages such as a greater driving force for mass transfer and minimal extractant quantity required (Li & Chen 2005). LM systems can also be automated and integrated with other separation techniques.

Phenols are commonly found in industrial wastewater and surface waters, posing environmental and health risks. An experiment using a SLM with tributyl phosphate (TBP) and sesame oil as the LM effectively extracted phenol under optimal conditions: 200 mg/L phenol concentration, 40% carrier concentration (%TBP), feed phase pH of 2, and stripping phase concentration of 1.1 M (Kazemi et al. 2014). Additionally, hydrophobic polypropylene membrane contactors, using Cyanex 923 as an extractant, achieved rapid phenol recovery, with a concentration ratio of approximately 39-fold and a 98% recovery rate (Reis et al. 2007). In the treatment of wastewater containing 1,050 mg/L nitrophenols, a LM process was employed, utilizing various parameters such as 2% surfactant concentration in the oil phase, 2% NaOH concentration in the internal water phase, a 2:1 ratio of oil phase to internal water phase, pH 2 in the external water phase, and a 3:1 ratio of external water phase to emulsion phase, resulting in a removal rate exceeding 99.99% for nitrophenols in wastewater (Luan & Plaisier 2004).

Efficient extraction of Palladium (Pd) from electroplating wastewater was achieved using a novel LM formulation with phosphonic acid groups as a carrier through the ELM process. Optimal conditions included 0.2 M Cyanex 302, 1.0 M thiourea in a 1.0 M H2SO4 stripping agent, 1:3 treatment ratio, pH 3 in the feed phase, and a 5-min extraction time, resulting in a maximum Pd extraction efficiency of 97% and a recovery of 40% (Othman et al. 2011).

Furthermore, chromium was successfully extracted from a wastewater solution containing waste sodium dichromate recovered from the pharmaceutical industry using the ELM technique. The LM consisted of kerosene oil as the solvent, SPAN-80 as the surfactant, potassium hydroxide as an internal reagent, and trioctylamine as the carrier. Response surface methodology optimization yielded the following conditions for optimal chromium extraction: a feed concentration of 224.04 ppm, pH 2.76, internal reagent concentration of 0.71 N, and a surfactant concentration of 1.92% (w/w), resulting in a maximum chromium extraction of 92.50% (Othman et al. 2011).

Additionally, an ELM was employed to extract Red 3BS reactive dye from an aqueous solution. Tridodecylamine (TDA) served as the carrier agent, salicylic acid (SA) was used to protonate TDA, sodium chloride acted as the stripping agent, and kerosene served as the diluent. SPAN 80 was utilized as an emulsifier. Under optimal conditions including 0.1 M SA, a 5-min extraction time, 3% (w/v) SPAN 80 concentration, 0.3 M NaCl concentration, 0.1 M TDA concentration, 350 rpm agitation speed, 12,000 rpm homogenizer speed, 10 min of emulsifying time, and a 1:15 emulsion to reactive dye solution ratio, nearly 100% removal of Red 3BS dye was achieved (Othman et al. 2011).

Membrane fouling stands as a significant challenge, greatly impeding the overall performance of membrane-based processes (Table 7). The accumulation of suspended solids, microorganisms, or organic substances within the membrane pores results in decreased permeate flux and the onset of membrane fouling. This fouling can manifest in various forms: (a) biological fouling stemming from the deposition and growth of biofilms on the membrane, (b) colloidal fouling caused by the buildup of microorganisms, biological detritus, polysaccharides, lipoproteins, clay, silt, oils, iron, and manganese oxides, (c) organic fouling due to the deposition of organic compounds, or (d) inorganic fouling (scale) brought about by the deposition of inorganic salts such as CaSO4, CaCO3, and SiO2 on the membrane surface. The extent of membrane fouling is influenced by various factors, including feed characteristics such as pH and ionic strength, membrane properties such as roughness and hydrophobicity, and process conditions such as cross-flow velocity, trans-membrane pressure, and temperature (Shon et al. 2002; Obotey Ezugbe & Rathilal 2020).

Membrane fouling leads to performance degradation, alterations in membrane selectivity, and increased membrane separation resistance. These effects, in turn, impact the separation factor for target species in the feed, ultimately resulting in unstable product quality and reduced recovery (Li & Chen 2010). Several methods can be employed to mitigate fouling in membranes, including pre-filters, surface shearing, chemical agents, and adjustments to operational conditions. Additionally, techniques such as ultrasound, backflushing, membrane oscillation, chemical cleaning, pore structure optimization, and membrane surface modification offer effective options for fouling mitigation (Jepsen et al. 2018; Ullah et al. 2021). A novel electro-assisted membrane coupling technology has contributed to addressing this problem by repelling foulants such as charged natural organic matter, colloids, and bacteria from membrane surfaces in the presence of an electric field (Li et al. 2018b).

As the global water crisis escalates, the search for effective and sustainable water purification technologies becomes increasingly crucial. Membrane technology, known for its efficiency and energy-conscious design, stands as a forefront solution to this challenge. Despite significant progress in water and wastewater treatment through material and module advancements, certain critical areas demand continuous attention. Fouling control and the pursuit of energy-efficient devices represent two key focal points for future exploration.

The persistent challenge of foulant accumulation on membranes requires innovative solutions. Research should focus on developing fouling-resistant membranes and exploring cost-effective pre-treatment techniques. A collaborative approach could yield breakthroughs in overcoming fouling, thereby enhancing the long-term efficiency of membrane systems. Energy efficiency remains an essential goal. Although the energy consumption of membrane processes has been significantly reduced, ongoing research is crucial to discovering novel ways to conserve energy in membrane-based water purification. Exploring hybrid techniques, such as the synergistic combination of forward-RO, holds immense promise. This hybrid approach, exemplified by its ability to eliminate high concentrations of phosphorus, ammonium, and salt from wastewater, signifies a leap toward resource-efficient water treatment.

As the research community refines these solutions, anchoring advancements in future economic viability and sustainability is essential. The application of cutting-edge technologies must align with practical constraints, emphasizing cost-effectiveness and environmental stewardship. Interdisciplinary collaboration and partnerships between researchers, engineers, policymakers, and industry players will play a crucial role in shaping the trajectory of water purification innovation. In conclusion, the journey toward enhanced water purification is not merely a scientific pursuit but a collective commitment to securing a sustainable water future. Through ongoing research, innovation, and collaborative efforts, the promise of accessible, clean water for all remains within our reach.

The authors are thankful to the Department of Chemical Engineering, Chungbuk National University, and the Department of Chemical Science and Engineering, Kathmandu University (DUT) for their support. Assistant Professor Dr Midori Yasui (Kyoto University, Japan), and Assistant Professor Dr Devrim Kaya (San Diego State University, USA) for making comments on different version of manuscript draft.

S. R. K. conceptualized, drafted, edited, and commented on the manuscript. S. A. and R. S. drafted, edited, and commented on the manuscript. S. B., G. K., P. G., and N. T. edited and commented on the manuscript. A. T. drafted, structured, edited, and commented on the manuscript. G. J. structured and edited. All authors have read and approved the final manuscript.

This research received no external funding.

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.

Abdel-Fatah
M. A.
2018
Nanofiltration systems and applications in wastewater treatment
.
Ain Shams Engineering Journal
9
(
4
),
3077
3092
.
Aguiar
A.
,
Andrade
L.
,
Grossi
L.
,
Pires
W.
&
Amaral
M.
2018
Acid mine drainage treatment by nanofiltration: A study of membrane fouling, chemical cleaning, and membrane ageing
.
Separation and Purification Technology
192
,
185
195
.
Ahmad
A.
,
Waheed
S.
,
Khan
S. M.
,
e-Gul
S.
,
Shafiq
M.
,
Farooq
M.
,
Sanaullah
K.
&
Jamil
T.
2015
Effect of silica on the properties of cellulose acetate/polyethylene glycol membranes for reverse osmosis
.
Desalination
355
,
1
10
.
Ahmed
S.
,
Mofijur
M.
,
Nuzhat
S.
,
Chowdhury
A. T.
,
Rafa
N.
,
Uddin
M. A.
,
Inayat
A.
,
Mahlia
T. M. I.
,
Ong
H. C.
,
Chia
W. Y.
&
Show
P. L.
2021
Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater
.
Journal of Hazardous Materials
416
,
125912
.
Alkhudhiri
A.
,
Darwish
N.
&
Hilal
N.
2012
Membrane distillation: A comprehensive review
.
Desalination
287
,
2
18
.
Alturki
A. A.
,
McDonald
J. A.
,
Khan
S. J.
,
Price
W. E.
,
Nghiem
L. D.
&
Elimelech
M.
2013
Removal of trace organic contaminants by the forward osmosis process
.
Separation and Purification Technology
103
,
258
266
.
Aptel
P.
,
Challard
N.
,
Cuny
J.
&
Neel
J.
1976
Application of the pervaporation process to separate azeotropic mixtures
.
Journal of Membrane Science
1
,
271
287
.
Arcanjo
G. S.
,
Ricci
B. C.
,
Dos Santos
C. R.
,
Costa
F. C. R.
,
Silva
U. C. M.
,
Mounteer
A. H.
,
Koch
K.
,
Da Silva
P. R.
,
Santos
V. L.
&
Amaral
M. C. S.
2021
Effective removal of pharmaceutical compounds and estrogenic activity by a hybrid anaerobic osmotic membrane bioreactor–membrane distillation system treating municipal sewage
.
Chemical Engineering Journal
416
,
129151
.
A Shirazi
M. M.
&
Kargari
A.
2015
A review on applications of membrane distillation (MD) process for wastewater treatment
.
Journal of Membrane Science and Research
1
(
3
),
101
112
.
Babaei
F.
,
Ehrampoush
M. H.
,
Eslami
H.
,
Ghaneian
M. T.
,
Fallahzadeh
H.
,
Talebi
P.
,
Fard
R. F.
&
Ebrahimi
A. A.
2019
Removal of linear alkylbenzene sulfonate and turbidity from greywater by a hybrid multi-layer slow sand filter microfiltration ultrafiltration system
.
Journal of Cleaner Production
211
,
922
931
.
Baker
R. W.
2012
Membrane Technology and Applications
.
John Wiley & Sons
,
Hoboken, NJ, USA
.
Bhattacharya, S., Saha, I., Mukhopadhyay, A., Chattopadhyay, D., Ghosh, U. C. & Chatterjee, D.
2013
Role of nanotechnology in water treatment and purification: Potential applications and implications
.
International Journal of Chemical Science and Technology
3
(
3
),
59
.
Bell
E. A.
,
Poynor
T. E.
,
Newhart
K. B.
,
Regnery
J.
,
Coday
B. D.
&
Cath
T. Y.
2017
Produced water treatment using forward osmosis membranes: Evaluation of extended-time performance and fouling
.
Journal of Membrane Science
525
,
77
88
.
Bera
S. P.
,
Godhaniya
M.
&
Kothari
C.
2022
Emerging and advanced membrane technology for wastewater treatment: A review
.
Journal of Basic Microbiology
62
(
3–4
),
245
259
.
Blandin
G.
,
Ferrari
F.
,
Lesage
G.
,
Le-Clech
P.
,
Héran
M.
&
Martinez-Lladó
X.
2020
Forward osmosis as concentration process: Review of opportunities and challenges
.
Membranes
10
(
10
),
284
.
Butterworth
R. F.
2010
Metal toxicity, liver disease and neurodegeneration
.
Neurotoxicity Research
18
,
100
105
.
Cao
X.
,
Wang
K.
&
Feng
X.
2021
Removal of phenolic contaminants from water by pervaporation
.
Journal of Membrane Science
623
,
119043
.
Cath
T. Y.
,
Childress
A. E.
&
Elimelech
M.
2006
Forward osmosis: Principles, applications, and recent developments
.
Journal of Membrane Science
281
(
1–2
),
70
87
.
Chimuka
L.
,
Cukrowska
E.
&
Jönsson
J. Å.
2004
Why liquid membrane extraction is an attractive alternative in sample preparation
.
Pure and Applied Chemistry
76
(
4
),
707
722
.
Curcio
E.
&
Drioli
E.
2005
Membrane distillation and related operations – A review
.
Separation and Purification Reviews
34
(
1
),
35
86
.
De Bruijn
F.
,
Sun
L.
,
Olujić
Ž.
,
Jansens
P. J.
&
Kapteijn
F.
2003
Influence of the support layer on the flux limitation in pervaporation
.
Journal of Membrane Science
223
(
1–2
),
141
156
.
De Wever
H.
,
Weiss
S.
,
Reemtsma
T.
,
Vereecken
J.
,
Müller
J.
,
Knepper
T.
,
Rörden
O.
,
Gonzalez
S.
,
Barcelo
D.
&
Dolores Hernando
M.
2007
Comparison of sulfonated and other micropollutants removal in membrane bioreactor and conventional wastewater treatment
.
Water Research
41
(
4
),
935
945
.
Drioli
E.
,
Ali
A.
&
Macedonio
F.
2015
Membrane distillation: Recent developments and perspectives
.
Desalination
356
,
56
84
.
Isnasyauqiah, Elma, M., Pradana, E. A., Ul-haq, M. D., Rampun, E. L. A., Rahma, A., Harivram, A. S. K., Assyaifi, Z. L. & Kamelia, Y.
2022
Hollow fiber membrane applied for Sasirangan wastewater desalination integrated with photocatalysis and pervaporation set-up
.
Materials Today: Proceedings
51
,
1298
1302
.
Farahbakhsh
K.
,
Svrcek
C.
,
Guest
R. K.
&
Smith
D. W.
2004
A review of the impact of chemical pretreatment on low-pressure water treatment membranes
.
Journal of Environmental Engineering and Science
3
(
4
),
237
253
.
Fu
C.
,
Cai
D.
,
Hu
S.
,
Miao
Q.
,
Wang
Y.
,
Qin
P.
,
Wang
Z.
&
Tan
T.
2016
Ethanol fermentation integrated with PDMS composite membrane: An effective process
.
Bioresource Technology
200
,
648
657
.
Fujioka
T.
,
Khan
S. J.
,
McDonald
J. A.
&
Nghiem
L. D.
2015
Rejection of trace organic chemicals by a hollow fibre cellulose triacetate reverse osmosis membrane
.
Desalination
368
,
69
75
.
Gan
G.
,
Fan
S.
,
Li
X.
,
Zhang
Z.
&
Hao
Z.
2023
Adsorption and membrane separation for removal and recovery of volatile organic compounds
.
Journal of Environmental Sciences
123
,
96
115
.
Garcia-Rodríguez
A.
,
Matamoros
V.
,
Fontàs
C.
&
Salvadó
V.
2014
The ability of biologically based wastewater treatment systems to remove emerging organic contaminants – A review
.
Environmental Science and Pollution Research
21
,
11708
11728
.
Gaur
N.
,
Narasimhulu
K.
&
PydiSetty
Y.
2018
Recent advances in the bio-remediation of persistent organic pollutants and its effect on environment
.
Journal of Cleaner Production
198
,
1602
1631
.
Ghaseminezhad
S. M.
,
Barikani
M.
&
Salehirad
M.
2019
Development of graphene oxide-cellulose acetate nanocomposite reverse osmosis membrane for seawater desalination
.
Composites Part B: Engineering
161
,
320
327
.
Goswami
L.
,
Vinoth Kumar
R.
,
Borah
S. N.
,
Arul Manikandan
N.
,
Pakshirajan
K.
&
Pugazhenthi
G.
2018
Membrane bioreactor and integrated membrane bioreactor systems for micropollutant removal from wastewater: A review
.
Journal of Water Process Engineering
26
,
314
328
.
Goswami
L.
,
Kumar
R. V.
,
Pakshirajan
K.
&
Pugazhenthi
G.
2019
A novel integrated biodegradation – microfiltration system for sustainable wastewater treatment and energy recovery
.
Journal of Hazardous Materials
365
,
707
715
.
Green
D.
&
Southard
M.
(eds)
2019
Section 9—Process economics
. In:
Perry's Chemical Engineers’ Handbook
, 7th edn.
McGraw-Hill Education
,
New York, NY, USA
, pp.
9
53
.
Guo
W.
,
Pan
B.
,
Sakkiah
S.
,
Yavas
G.
,
Ge
W.
,
Zou
W.
,
Tong
W.
&
Hong
H.
2019
Persistent organic pollutants in food: Contamination sources, health effects and detection methods
.
International Journal of Environmental Research and Public Health
16
(
22
),
4361
.
Hailemariam
R. H.
,
Woo
Y. C.
,
Damtie
M. M.
,
Kim
B. C.
,
Park
K.-D.
&
Choi
J.-S.
2020
Reverse osmosis membrane fabrication and modification technologies and future trends: A review
.
Advances in Colloid and Interface Science
276
,
102100
.
Han
L.
,
Tan
Y. Z.
,
Netke
T.
,
Fane
A. G.
&
Chew
J. W.
2017
Understanding oily wastewater treatment via membrane distillation
.
Journal of Membrane Science
539
,
284
294
.
Hanafi
M. F.
&
Sapawe
N.
2020
A review on the current techniques and technologies of organic pollutants removal from water/wastewater
.
Materials Today: Proceedings
31
(
1
),
A158
A165
.
doi:10.1016/j.matpr.2021.01.265
.
Howe
K. J.
,
Hand
D. W.
,
Crittenden
J. C.
,
Trussell
R. R.
&
Tchobanoglous
G.
2012
Principles of Water Treatment
.
John Wiley & Sons
,
Hoboken, NJ, USA
.
Huang
H.
,
Schwab
K.
&
Jacangelo
J. G.
2009
Pretreatment for low pressure membranes in water treatment: A review
.
Environmental Science & Technology
43
(
9
),
3011
3019
.
Jacangelo
J. G.
,
Trussell
R. R.
&
Watson
M.
1997
Role of membrane technology in drinking water treatment in the United States
.
Desalination
113
(
2–3
),
119
127
.
Jefferson
B.
,
Laine
A. L.
,
Judd
S. J.
&
Stephenson
T.
2000
Membrane bioreactors and their role in wastewater reuse
.
Water Science and Technology
41
(
1
),
197
204
.
Jin
X.
,
Shan
J.
,
Wang
C.
,
Wei
J.
&
Tang
C. Y.
2012
Rejection of pharmaceuticals by forward osmosis membranes
.
Journal of Hazardous Materials
227
,
55
61
.
Juang
Y.
,
Nurhayati
E.
,
Huang
C.
,
Pan
J. R.
&
Huang
S.
2013
A hybrid electrochemical advanced oxidation/microfiltration system using BDD/Ti anode for acid yellow 36 dye wastewater treatment
.
Separation and Purification Technology
120
,
289
295
.
Juholin
P.
,
Kääriäinen
M.-L.
,
Riihimäki
M.
,
Sliz
R.
,
Aguirre
J. L.
,
Pirilä
M.
,
Fabritius
T.
,
Cameron
D.
&
Keiski
R. L.
2018
Comparison of ALD coated nanofiltration membranes to unmodified commercial membranes in mine wastewater treatment
.
Separation and Purification Technology
192
,
69
77
.
Kazemi
P.
,
Peydayesh
M.
,
Bandegi
A.
,
Mohammadi
T.
&
Bakhtiari
O.
2014
Stability and extraction study of phenolic wastewater treatment by supported liquid membrane using tributyl phosphate and sesame oil as liquid membrane
.
Chemical Engineering Research and Design
92
(
2
),
375
383
.
Khan
F. I.
&
Ghoshal
A. K.
2000
Removal of volatile organic compounds from polluted air
.
Journal of Loss Prevention in the Process Industries
13
(
6
),
527
545
.
Kyburz
M.
,
Meindersma
G. W.
&
Bargeman
G.
2021
Nanofiltration in the chemical processing industry
.
Nanofiltration: Principles, Applications, and New Materials
2
,
543
597
.
Le-Clech
P.
,
Chen
V.
&
Fane
T. A.
2006
Fouling in membrane bioreactors used in wastewater treatment
.
Journal of Membrane Science
284
(
1–2
),
17
53
.
Lee
A.
,
Elam
J. W.
&
Darling
S. B.
2016
Membrane materials for water purification: Design, development, and application
.
Environmental Science: Water Research & Technology
2
(
1
),
17
42
.
Li
N. N.
1968
Separating hydrocarbons with liquid membranes. Google Patents
.
Li
N. N.
1978
Facilitated transport through liquid membranes
.
Journal of Membrane Science
3
(
2
),
265
269
.
Li
J.-L.
&
Chen
B.-H.
2005
Review of CO2 absorption using chemical solvents in hollow fiber membrane contactors
.
Separation and Purification Technology
41
(
2
),
109
122
.
Li
H.
&
Chen
V.
2010
Membrane fouling and cleaning in food and bioprocessing
. In:
Membrane Technology
(Cui, Z. F. & Muralidhara, H. S. (eds)).
Elsevier
,
Amsterdam, Netherlands
, pp.
213
254
.
Li
L.
&
Visvanathan
C.
2017
Membrane technology for surface water treatment: Advancement from microfiltration to membrane bioreactor
.
Reviews in Environmental Science and Bio/Technology
16
,
737
760
.
Li
D.
,
Yao
J.
,
Sun
H.
,
Liu
B.
,
Li
D.
,
Van Agtmaal
S.
&
Feng
C.
2018a
Preparation and characterization of SiO2/PDMS/PVDF composite membrane for phenols recovery from coal gasification wastewater in pervaporation
.
Chemical Engineering Research and Design
132
,
424
435
.
Li
C.
,
Guo
X.
,
Wang
X.
,
Fan
S.
,
Zhou
Q.
,
Shao
H.
,
Hu
W.
,
Li
C.
,
Tong
L.
&
Kumar
R. R.
2018b
Membrane fouling mitigation by coupling applied electric field in membrane system: Configuration, mechanism and performance
.
Electrochimica Acta
287
,
124
134
.
Li
C.
,
Deng
W.
,
Gao
C.
,
Xiang
X.
,
Feng
X.
,
Batchelor
B.
&
Li
Y.
2019
Membrane distillation coupled with a novel two-stage pretreatment process for petrochemical wastewater treatment and reuse
.
Separation and Purification Technology
224
,
23
32
.
Li
C.
,
Feng
G.
,
Pan
Z.
,
Song
C.
,
Fan
X.
,
Tao
P.
,
Wang
T.
,
Shao
M.
&
Zhao
S.
2020
High-performance electrocatalytic microfiltration CuO/Carbon membrane by facile dynamic electrodeposition for small-sized organic pollutants removal
.
Journal of Membrane Science
601
,
117913
.
Li
Y.
,
Huo
B.
,
Xu
Z.
,
Qi
H.
,
Li
X.
,
Cui
P.
,
Zhu
Z.
,
Wang
Y.
,
Yang
J.
&
Gao
J.
2022
Energy-saving and environmentally friendly pervaporation-distillation hybrid process for alcohol and ester recovery from wastewater containing three binary azeotropes
.
Separation and Purification Technology
281
,
119889
.
Liao
Y.
,
Zheng
G.
,
Huang
J. J.
,
Tian
M.
&
Wang
R.
2020
Development of robust and superhydrophobic membranes to mitigate membrane scaling and fouling in membrane distillation
.
Journal of Membrane Science
601
,
117962
.
Lim
S. K.
,
Goh
K.
,
Bae
T.-H.
&
Wang
R.
2017
Polymer-based membranes for solvent-resistant nanofiltration: A review
.
Chinese Journal of Chemical Engineering
25
(
11
),
1653
1675
.
Lin
H.
,
Gao
W.
,
Meng
F.
,
Liao
B.-Q.
,
Leung
K.-T.
,
Zhao
L.
,
Chen
J.
&
Hong
H.
2012
Membrane bioreactors for industrial wastewater treatment: A critical review
.
Critical Reviews in Environmental Science and Technology
42
(
7
),
677
740
.
Liu
P.
,
Zhang
H.
,
Feng
Y.
,
Shen
C.
&
Yang
F.
2015
Integrating electrochemical oxidation into forward osmosis process for removal of trace antibiotics in wastewater
.
Journal of Hazardous Materials
296
,
248
255
.
Liu
L.
,
Xie
X.
,
Qi
S.
,
Li
R.
,
Zhang
X.
,
Song
X.
&
Gao
C.
2019
Thin film nanocomposite reverse osmosis membrane incorporated with UiO-66 nanoparticles for enhanced boron removal
.
Journal of Membrane Science
580
,
101
109
.
Liu
C.
,
Dong
G.
,
Tsuru
T.
&
Matsuyama
H.
2021a
Organic solvent reverse osmosis membranes for organic liquid mixture separation: A review
.
Journal of Membrane Science
620
,
118882
.
Liu
C.
,
Takagi, R., Saeki, D., Cheng, L., Shintani, T., Yasui, T. & Matsuyama, H.
2021b
Highly improved organic solvent reverse osmosis (OSRO) membrane for organic liquid mixture separation by simple heat treatment
.
Journal of Membrane Science
618
,
118710
.
Luan
J.
&
Plaisier
A.
2004
Study on treatment of wastewater containing nitrophenol compounds by liquid membrane process
.
Journal of Membrane Science
229
(
1–2
),
235
239
.
Luo
W.
,
Phan, H. V., Li, G., Hai, F. I., Price, W. E., Elimelech, M. & Nghiem, L. D.
2017
An osmotic membrane bioreactor–membrane distillation system for simultaneous wastewater reuse and seawater desalination: Performance and implications
.
Environmental Science & Technology
51
(
24
),
14311
14320
.
Madsen
H. T.
,
Bajraktari, N., Hélix-Nielsen, C., Van Der Bruggen, B. & Søgaard, E. G.
2015
Use of biomimetic forward osmosis membrane for trace organics removal
.
Journal of Membrane Science
476
,
469
474
.
Malkoske
T. A.
,
Bérubé
P. R.
&
Andrews
R. C.
2020
Coagulation/flocculation prior to low pressure membranes in drinking water treatment: A review
.
Environmental Science: Water Research & Technology
6
(
11
),
2993
3023
.
Mameda
N.
,
Park
H.
,
Shah
S. S. A.
,
Lee
K.
,
Li
C.-W.
,
Naddeo
V.
&
Choo
K.-H.
2020
Highly robust and efficient Ti-based Sb-SnO2 anode with a mixed carbon and nitrogen interlayer for electrochemical 1, 4-dioxane removal from water
.
Chemical Engineering Journal
393
,
124794
.
Marchetti
P.
,
Jimenez Solomon
M. F.
,
Szekely
G.
&
Livingston
A. G.
2014
Molecular separation with organic solvent nanofiltration: A critical review
.
Chemical Reviews
114
(
21
),
10735
10806
.
Melliti
E.
,
Touati
K.
,
Abidi
H.
&
Elfil
H.
2019
Iron fouling prevention and membrane cleaning during reverse osmosis process
.
International Journal of Environmental Science and Technology
16
(
7
),
3809
3818
.
Mohammad
A. W.
,
Teow
Y. H.
,
Ang
W. L.
,
Chung
Y. T.
,
Oatley-Radcliffe
D. L.
&
Hilal
N.
2015
Nanofiltration membranes review: Recent advances and future prospects
.
Desalination
356
,
226
254
.
Mulyanti
R.
&
Susanto
H.
2018
Wastewater treatment by nanofiltration membranes
. In
IOP Conference Series: Earth and Environmental Science
.
IOP Publishing
,
Bristol, UK
.
Nath
K.
2017
Membrane Separation Processes
.
PHI Learning Pvt. Ltd
,
Delhi, India
.
Nath
K.
,
Dave
H. K.
&
Patel
T. M.
2018
Revisiting the recent applications of nanofiltration in food processing industries: Progress and prognosis
.
Trends in Food Science & Technology
73
,
12
24
.
Nie
L.
,
Chuah
C. Y.
,
Bae
T.
&
Lee
J.
2021
Graphene-based advanced membrane applications in organic solvent nanofiltration
.
Advanced Functional Materials
31
(
6
),
2006949
.
Noble
R. D.
&
Way
J. D.
1987
Liquid Membranes: Theory and Applications
.
American Chemical Society
,
Washington, DC, USA
.
Nqombolo
A.
,
Mpupa
A.
,
Moutloali
R. M.
&
Nomngongo
P. N.
2018
Wastewater treatment using membrane technology
.
Wastewater and Water Quality
29
,
30
40
.
Obotey Ezugbe
E.
&
Rathilal
S.
2020
Membrane technologies in wastewater treatment: A review
.
Membranes
10
(
5
),
89
.
Onsekizoglu
P.
2012
Membrane distillation: Principle, advances, limitations and future prospects in food industry
. In:
Zereshki, S. (ed.)
Distillation – Advances from Modeling to Applications.
InTech
, p.
282
.
Ouyang
W.
,
Chen
T.
,
Shi
Y.
,
Tong
L.
,
Chen
Y.
,
Wang
W.
,
Yang
J.
&
Xue
J.
2019
Physico-chemical processes
.
Water Environment Research
91
(
10
),
1350
1377
.
Park
S.-H.
,
Kwon
S. J.
,
Shin
M. G.
,
Park
M. S.
,
Lee
J. S.
,
Park
C. H.
,
Park
H.
&
Lee
J.-H.
2018
Polyethylene-supported high performance reverse osmosis membranes with enhanced mechanical and chemical durability
.
Desalination
436
,
28
38
.
Ramos
R. L.
,
Martins
M. F.
,
Lebron
Y. A. R.
,
Moreira
V. R.
,
Reis
B. G.
,
Grossi
L. B.
&
Amaral
M. C. S.
2021
Membrane distillation process for phenolic compounds removal from surface water
.
Journal of Environmental Chemical Engineering
9
(
4
),
105588
.
Reis
M. T. A.
,
De Freitas
O. M. F.
,
Ismael
M. R. C.
&
Carvalho
J. M. R.
2007
Recovery of phenol from aqueous solutions using liquid membranes with Cyanex 923
.
Journal of Membrane Science
305
(
1–2
),
313
324
.
Rezakazemi
M.
,
Marjani
A.
&
Shirazian
S.
2018
Organic solvent removal by pervaporation membrane technology: Experimental and simulation
.
Environmental Science and Pollution Research
25
(
20
),
19818
19825
.
Riley
S. M.
,
Oliveira
J. M. S.
,
Regnery
J.
&
Cath
T. Y.
2016
Hybrid membrane bio-systems for sustainable treatment of oil and gas produced water and fracturing flowback water
.
Separation and Purification Technology
171
,
297
311
.
Rout
P. R.
,
Zhang
T. C.
,
Bhunia
P.
&
Surampalli
R. Y.
2021
Treatment technologies for emerging contaminants in wastewater treatment plants: A review
.
Science of the Total Environment
753
,
141990
.
Said
I. A.
,
Chomiak
T. R.
,
He
Z.
&
Li
Q.
2020
Low-cost high-efficiency solar membrane distillation for treatment of oil produced waters
.
Separation and Purification Technology
250
,
117170
.
San Román
M.
,
Bringas
E.
,
Ibañez
R.
&
Ortiz
I.
2010
Liquid membrane technology: Fundamentals and review of its applications
.
Journal of Chemical Technology & Biotechnology
85
(
1
),
2
10
.
Sauchelli
M.
,
Pellegrino
G.
,
D'Haese
A.
,
Rodríguez-Roda
I.
&
Gernjak
W.
2018
Transport of trace organic compounds through novel forward osmosis membranes: Role of membrane properties and the draw solution
.
Water Research
141
,
65
73
.
Sekulić
J.
,
ten Elshof
J. E.
&
Blank
D. H.
2005
Separation mechanism in dehydration of water/organic binary liquids by pervaporation through microporous silica
.
Journal of Membrane Science
254
(
1–2
),
267
274
.
Shahid
M. K.
,
Kashif
A.
,
Fuwad
A.
&
Choi
Y.
2021
Current advances in treatment technologies for removal of emerging contaminants from water – A critical review
.
Coordination Chemistry Reviews
442
,
213993
.
Shin
M. G.
,
Park
S.-H.
,
Kwon
S. J.
,
Kwon
H.-E.
,
Park
J. B.
&
Lee
J.-H.
2019
Facile performance enhancement of reverse osmosis membranes via solvent activation with benzyl alcohol
.
Journal of Membrane Science
578
,
220
229
.
Shon
H.
,
Vigneswaran
S.
&
Kandasamy
J.
2002
Membrane Technology for Organic Removal in Wastewater
.
Encyclopedia of Life Support Systems (EOLSS)
.
Shon
H.
,
Phuntsho
S.
,
Chaudhary
D. S.
,
Vigneswaran
S.
&
Cho
J.
2013
Nanofiltration for water and wastewater treatment – A mini review
.
Drinking Water Engineering and Science
6
(
1
),
47
53
.
Singh
R.
&
Hankins
N.
2016
Emerging Membrane Technology for Sustainable Water Treatment
.
Elsevier
,
Amsterdam, Netherlands
.
Singh
R.
&
Purkait
M. K.
2019
Microfiltration membranes
. In:
Membrane Separation Principles and Applications
.
Elsevier
,
Amsterdam, Netherlands
, pp.
111
146
.
Sonawane
S.
,
Thakur
P.
,
Sonawane
S. H.
&
Bhanvase
B. A.
2021
Nanomaterials for membrane synthesis: Introduction, mechanism, and challenges for wastewater treatment
. In:
Handbook of Nanomaterials for Wastewater Treatment
.
Elsevier
,
Amsterdam, Netherlands
, pp.
537
553
.
Subramaniam
M. N.
,
Goh
P.-S.
,
Lau
W.-J.
,
Ng
B.-C.
&
Ismail
A. F.
2019
Development of nanomaterial-based photocatalytic membrane for organic pollutants removal
. In:
Advanced Nanomaterials for Membrane Synthesis and Its Applications
.
Elsevier
,
Amsterdam, Netherlands
, pp.
45
67
.
Tadkaew
N.
,
Sivakumar
M.
,
Khan
S. J.
,
McDonald
J. A.
&
Nghiem
L. D.
2010
Effect of mixed liquor pH on the removal of trace organic contaminants in a membrane bioreactor
.
Bioresource Technology
101
(
5
),
1494
1500
.
Toth
A. J.
,
Haaz
E.
,
Nagy
T.
,
Tarjani
A.J.
,
Fozer
D.
,
Andre
A.
,
Valentinyi
N.
,
Solti
S.
&
Mizsey
P.
2018
Treatment of pharmaceutical process wastewater with hybrid separation method: Distillation and hydrophilic pervaporation
.
Waste Treatment and Recovery
3
(
1
),
8
13
.
Ullah
A.
,
Tanudjaja
H. J.
,
Ouda
M.
,
Hasan
S. W.
&
Chew
J. W.
2021
Membrane fouling mitigation techniques for oily wastewater: A short review
.
Journal of Water Process Engineering
43
,
102293
.
Urošević
T.
&
Trivunac
K.
2020
Achievements in low-pressure membrane processes microfiltration (MF) and ultrafiltration (UF) for wastewater and water treatment
. In:
Current Trends and Future Developments on (Bio-) Membranes
.
Elsevier
,
Amsterdam, Netherlands
, pp.
67
107
.
Van der Merwe
I.
1998
Application of nanofiltration in metal recovery
.
Journal of the Southern African Institute of Mining and Metallurgy
98
(
7
),
339
341
.
Van Dijk
L.
&
Roncken
G.
1997
Membrane bioreactors for wastewater treatment: The state of the art and new developments
.
Water Science and Technology
35
(
10
),
35
41
.
van't Oever
R.
2005
MBR focus: Is submerged best?
Filtration & Separation
42
(
5
),
24
27
.
Voicu
S.
&
Thakur
V.
2021
Graphene-based composite membranes for nanofiltration: Performances and future perspectives
.
Emergent Materials
5
,
1429
1441
.
Wang
Y.
,
Mei, X., Ma, T., Xue, C., Wu, M., Ji, M. & Li, Y.
2018
Green recovery of hazardous acetonitrile from high-salt chemical wastewater by pervaporation
.
Journal of Cleaner Production
197
,
742
749
.
Wang
H.
,
Li, C., Xu, Q., Liu, C., Zhang, Z., Du, X., Hao, X. & Guan, G.
2021a
Mass transport and pervaporation recovery of aniline with high-purity from dilute aqueous solution by PEBA/PVDF composite membranes
.
Separation and Purification Technology
268
,
118708
.
Wang
Z.
,
Qin, Y., Xu, X., Sun, J., Shen, J., Ning, X. & Li, N.
2021b
Laminated graphene oxide membrane for recovery of mercury-containing wastewater by pervaporation
.
Applied Water Science
11
(
7
),
1
10
.
Warsinger
D. M.
,
Chakraborty, S., Tow, E. W., Plumlee, M. H., Bellona, C., Loutatidou, S., Karimi, L., Mikelonis, A. M., Achilli, A. & Ghassemi, A.
2018
A review of polymeric membranes and processes for potable water reuse
.
Progress in Polymer Science
81
,
209
237
.
Wijekoon
K. C.
,
Hai, F. I., Kang, J., Price, W. E., Cath, T. Y. & Nghiem, L. D.
2014
Rejection and fate of trace organic compounds (TrOCs) during membrane distillation
.
Journal of Membrane Science
453
,
636
642
.
Wolf
K.
,
Yazdani
A.
&
Yates
P.
1991
Chlorinated solvents: Will the alternatives be safer?
Journal of the Air & Waste Management Association
41
(
8
),
1055
1061
.
Xie
M.
,
Nghiem, L. D., Price, W. E. & Elimelech, M.
2013
A forward osmosis–membrane distillation hybrid process for direct sewer mining: System performance and limitations
.
Environmental Science & Technology
47
(
23
),
13486
13493
.
Yadav
S.
,
Ibrar, I., Bakly, S., Khanafer, D., Altaee, A., Padmanaban, V. C., Samal, A. K. & Hawari, A. H.
2020
Organic fouling in forward osmosis: A comprehensive review
.
Water
12
(
5
),
1505
.
Yang
Z.
,
Zhou, Y., Feng, Z., Rui, X., Zhang, T. & Zhang, Z.
2019
A review on reverse osmosis and nanofiltration membranes for water purification
.
Polymers
11
(
8
),
1252
.
Yao
L.
,
Qin, Z., Chen, Q., Zhao, M., Zhao, H., Ahmad, W., Fan, L. & Zhao, L.
2018
Insights into the nanofiltration separation mechanism of monosaccharides by molecular dynamics simulation
.
Separation and Purification Technology
205
,
48
57
.
Yao
M.
,
Duan, L., Song, Y. & Hermanowicz, S. W.
2021
Degradation mechanism of Ibuprofen via a forward osmosis membrane bioreactor
.
Bioresource Technology
321
,
124448
.
Zhang
X.
,
Ning, Z., Wang, D. K. & Diniz Da Costa, J. C.
2014
Processing municipal wastewaters by forward osmosis using CTA membrane
.
Journal of Membrane Science
468
,
269
275
.
Zhao
G.
,
Zou
J.
,
Chen
X.
,
Zhang
T.
,
Yu
J.
,
Zhou
S.
,
Li
C.
&
Jiao
F
.
2020
Integration of microfiltration and visible-light-driven photocatalysis on a ZnWO4 nanoparticle/nickel–aluminum-layered double hydroxide membrane for enhanced water purification
.
Industrial & Engineering Chemistry Research
59
(
14
),
6479
6487
.
Zou
Q.
,
Zhang
Z.
,
Li
H.
,
Pei
W.
,
Ding
M.
,
Xie
Z.
,
Huo
Y.
&
Li
H.
2020
Synergistic removal of organic pollutant and metal ions in photocatalysis-membrane distillation system
.
Applied Catalysis B: Environmental
264
,
118463
.

Author notes

Equally contributed to this work.

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