Abstract

Industrial effluents are usually one of the major industries polluting the environment and surface water. It is estimated that the worldwide production of dyes is about 70 tons/year. To overcome this problem, innovative processes are suggested for the treatment of industrial effluents containing dyes and heavy metals. The goal of the processes is often to reduce the toxicity of these pollutants in order to meet treatment standards. Recently, great attention has been paid to innovative processes for physical and chemical removal techniques such as adsorption on new adsorbents, biomass adsorption, membrane filtration, irradiation, and electrochemical coagulation. In this study, the application of adsorbents in the adsorption process to remove dye pollutants from industrial effluents has been studied. Factors affecting dye adsorption such as pH, temperature, initial dye concentration, and adsorbent amount are also presented. The obtained results revealed that more than 80% of the dye adsorption on the surface of adsorbents are endothermic processes and more than 95% of the processes obey the pseudo-second-order kinetic model.

HIGHLIGHTS

  • Investigation of the influence of different adsorbents and different adsorption process parameters.

  • Factors affecting dye adsorption.

  • Regenerability of adsorbents in the adsorption process to make the adsorption process more economical.

  • Application of adsorbents in the adsorption process to remove dye from industrial effluents.

Graphical Abstract

Graphical Abstract
Graphical Abstract

INTRODUCTION

In recent years, adsorption processes have shown effective results on water and wastewater treatment technology in different industries. In these techniques, a series of natural or synthesized adsorbents have been used to treat contaminants such as metals, dyes, and pharmaceutical products in solutions (Hajipour et al. 2021). These adsorbents can be regenerated or consumed after the adsorption process. Synthetic dyes are widely used in many advanced industries such as various textiles, paper, leather, food process, plastics, cosmetics, printing, and industrial dyes (Benkhaya et al. 2020). The entry of synthetic dyes into industrial effluents and their discharge into aqueous solutions has caused considerable environmental issues in recent years (Al-Sakkaf et al. 2020). The presence of dye pollutants in water will reduce sunlight penetration and negatively affect the photosynthetic activity (Misra et al. 2020). To date, more than 100,000 industrial dyes with an annual production of more than 7 × 105 tons/year are known (Adegoke & Bello 2015). Textile industries consume more than 100,000 tons/year dyes, and about 100 tons/year of dye enters the effluent water (Mosbah et al. 2019). There is no exact information on the amount of dye released from various processes to the environment. However, scientists have identified the release of actual amounts of artificial colors into the environment as an environmental challenge (Lellis et al. 2019; Javidparvar et al. 2020). Various methods such as adsorption (Konicki et al. 2017), coagulation (Kosaka et al. 2018), advanced oxidation (Javaid & Qazi 2019) and separation of membranes and nanosorbents (Karim et al. 2014; Abdi et al. 2018) have been used to remove dyes from wastewater.

Adsorption is an effective process in advanced wastewater treatment techniques to reduce the effluent risks of high pollutants and minerals (Khulbe & Matsuura 2018). Many textile industries use commercial activated carbon to treat colored effluents (Briton et al. 2020). Many researchers have reported the possibility of using cheap adsorbents derived from natural materials, industrial, and agricultural solid waste (Sulyman et al. 2017). The use of biosorbents to improve the adsorption capacity has been reported by researchers (Adewuyi 2020). Several groups of dyes are stable molecules resistant to decomposition by light, chemicals, biological, and other factors and are considered mutagens for humans (Badran & Khalaf 2019; Javaid & Qazi 2019). Most dyes are complex organic molecules that require resistance to external agents such as detergents (Julkapli et al. 2014). Dye molecules are made up of two components: the dye agent, which is responsible for the color formation, and the enhancer, which is responsible for amplifying the dye agent, its solubility in water, and binding to the surface (Bisht & Lal 2019). Therefore, dye-contaminated wastewater must be treated appropriately before being released into the environment (Basheer 2018). In general, colors can be classified according to their structure, application, the charge of particles, or color in the solution. Table 1 shows the classification of colors based on their different applications (Hou et al. 2011; Yu et al. 2016).

Table 1

Classify different colors based on their application (Hou et al. 2011; Yu et al. 2016)

CategorySub-layer
Acidic Wool, nylon, silk, ink, leather, and paper 
Basic Ink, paper, polyacrylic and nitrile, processed nylon, and polyester 
Direct Nylon, rayon, paper, leather, and linen 
Disperse Polyamide, acrylic polyester, acetate, and plastic 
Reactive Wool, linen, silk, and nylon 
Sulfur Rayon and linen 
Vat Cotton, wool, and linen 
CategorySub-layer
Acidic Wool, nylon, silk, ink, leather, and paper 
Basic Ink, paper, polyacrylic and nitrile, processed nylon, and polyester 
Direct Nylon, rayon, paper, leather, and linen 
Disperse Polyamide, acrylic polyester, acetate, and plastic 
Reactive Wool, linen, silk, and nylon 
Sulfur Rayon and linen 
Vat Cotton, wool, and linen 

Base colors have a high color intensity and can be seen in low concentrations (Nelis et al. 2019). Complex dyes are generally based on chromium, which is carcinogenic (Chakraborty et al. 2020). Azo dyes are toxic due to the presence of toxic amines in the effluents (Sarkar et al. 2017). Anthraquinone-based dyes are also the most resistant dyes to decomposition and remain in the effluent for a long time (Ray et al. 2020). Reactive dyes are soluble in water, and 5–10% of these dyes enter the dye bath and are present in the colored effluent, which creates serious problems for the environment (Hynes et al. 2020). Removal of reactive dyes and their degradability in biological systems using conventional wastewater treatment techniques is low (Dayı et al. 2020). For this reason, focusing on specific methods of removing dye from industrial effluents helps to select a treatment system appropriate to the type of pollution. The main purpose and novelty of this review study are to investigate the application of new and inexpensive adsorbents for the removal of dye compounds from industrial wastewater. In addition, physical and chemical adsorption processes and parameters affecting adsorption capacity are presented. Adsorption kinetics, isotherm models, thermodynamics, and adsorption capacity are collected under different process conditions. Therefore, an overview of the most comprehensive updated information on the adsorption of different colors from aqueous solution by a wide range of adsorbents has been provided in the current work. Over the past two decades, attempts have also been made to use a wide range of adsorbents to analyze color adsorption information (Ali 2013).

AVAILABLE TECHNOLOGIES FOR DYE REMOVAL

There are currently not many ways to remove dye from the effluents. Despite the availability of many techniques for eliminating dye contaminants from wastewater, such as flocculation, chemical oxidation of membranes, separation processes, electrochemical and aerobic, and microbial anaerobic (Rajasulochana & Preethy 2016; Zaied et al. 2020), inherent limitations have been involved by each of these methods (Ghoreishi & Haghighi 2003).

Utilizing biological processes to remove dye from wastewater has grown recently, gaining several research groups' attention. In this method, a new strain of microbe resistant to the microbe contacted the toxic waste that would convert into a less harmful form. The biodegradation mechanism is based on the biotransformation enzymes, which would lead to the biodegradation of recalcitrant compounds in the microbial system. Several enzymes such as tyrosinase, hexane oxidase, demethylase, laccase, or lignin peroxidase were used as the biodegradation agent. However, the degradation of azo dyes by enzymes or a combination of physical methods has gained attention from several biotechnological approaches (Kumar et al. 2012).

Physical methods operate based on the mass transfer mechanism and usually consist of straightforward systems to remove dye from wastewater. Ion exchange, irradiation, adsorption, coagulation, and membrane filtration are the conventional physical processes that were used for the separation process. However, among the mentioned methods (chemical, biological, and physical), physical methods are implemented to remove the dye commonly due to ease of use, simple operation conditions, and more efficient processes. Adsorption method has been considered as the very effective method for utilizing in the dye removal process because of several factors, such as low operation cost, reusability of adsorbent, low material consumption, or excellent properties of adsorbent material (e.g., high surface area and high adsorption capacity) (Ghoreishi & Haghighi 2003). Several adsorbents with different features were utilized for the adsorption of dyes, as tabulated in Supplementary Material, Table S2. The pore diameter is also one of the most important features of adsorbent materials that would affect adsorbent selectivity based on the diameter of adsorbed material (Kumar et al. 2012).

Table 2

Correlation of RL with the Langmuir isotherm

Isotherm situationRL
Undesirable RL > 1 
Linear RL = 1 
Desired 0 < RL < 1 
Reversible RL = 0 
Isotherm situationRL
Undesirable RL > 1 
Linear RL = 1 
Desired 0 < RL < 1 
Reversible RL = 0 

Various factors affect the way and capacity of the dye adsorption. The most effective of these factors are solution pH, temperature, initial concentration, and amount of adsorbent (Rápó et al. 2020). Optimizing these conditions will greatly affect the development of the dye removal process on an industrial scale. Some of the factors affecting color adsorption that have been investigated in most studies are reviewed in the following sections.

Effect of pH

Acidity of the solution is one of the most important factors affecting the adsorbent capacity in wastewater treatment. Adsorption efficiency depends on the pH of the solution because changes in pH lead to changes in the degree of melting properties (Kumar et al. 2019). Therefore, pH is mentioned as an important parameter in color adsorption. The adsorption ability and active centers on the surface depend on the zero electric charge point called the surface Pzc (Skwarek et al. 2016). This point is directly affected by the used pH solution, pHpzc, in which surface charge is zero, typically used to quantify the electromagnetic properties of the surface (Jouniaux & Ishido 2012).

The pH value to describe Pzc is only for systems in which H+/OH ions are predominant. Many researchers have studied the Pzc point of many different adsorbents prepared from agricultural effluents to understand the mechanism of adsorption. The adsorption of cationic dyes at pH > pHpzc is desirable due to the functional group, OH group, while the adsorption of anionic dyes at pH < pHpzc is desirable, where the surface is positively charged (Elwakeel et al. 2020).

Effect of dye initial concentration

The effect of initial dye concentration is closely related to the dye concentration and the sites present on the adsorbent surface. In general, the percentage of dye removal decreases with increasing initial dye concentration, which leads to a saturation of adsorption sites on the adsorbent surface (Son et al. 2016). On the other hand, increasing the initial concentration of the dye increases the adsorption capacity due to the high driving force of mass transfer in the initial high concentration of dye.

Effect of temperature

Temperature is another important parameter in the physico-chemical adsorption process due to the fact that the amount of adsorbent capacity can be related to the process temperature (Jiang et al. 2018). If the amount of adsorption sites increases with increasing temperature, this indicates that the adsorption process is endothermic. This may be due to the increment of the mobility of dye molecules, as the number of active sites for adsorption increases with increasing the process temperature (Wong et al. 2020). On the other hand, there are several adsorption processes in which increases in temperature adsorption capacity have declined, indicating the exothermic adsorption process (Belhamdi et al. 2016; Peng et al. 2020; Romdhane et al. 2020). In this kind of adsorption, the adsorption forces between the dye species and the active sites on the adsorbent surface decreased, resulting in a decrease in the adsorption process.

Amount of adsorbent

The amount of adsorbent is an important parameter for determining the adsorbent capacity for a given amount of adsorbent under operating conditions. In general, the percentage of dye removal increases with increasing the amount of adsorbent with increasing the number of adsorption sites on the adsorbent surface. The effect of the amount of adsorbent material presents an idea for the adsorption process, which is economically viable (Salleh et al. 2011).

Kinetic study of dye adsorption

Several kinetic models are used in different laboratory conditions to investigate adsorption mechanisms, such as chemical reaction, diffusion control, and mass transfer. The information obtained from adsorption kinetics can be examined to understand the dynamics of adsorption reactions. The study of adsorption kinetics is useful for designing and modeling the process to predict the adsorption rate. The adsorption capacity at all stages of optimization is calculated from the qe relation (Equation (1)).
formula
(1)
where in this equation, C0, Ce, V, and M are initial dye concentration (mg/L), equilibrium dye concentration (mg/L), solution volume (L), and sorbent weight (g), respectively.
Dye removal percentage (color adsorption efficiency) is also obtained from the following equation:
formula
(2)

Kinetic and thermodynamic adsorption models are widely discussed in the Supplementary material.

Application of various isotherm models in dye removal

Equilibrium adsorption isotherm models are essential requirements for the design of adsorption systems and the interaction between adsorbent and adsorbent. Models used to analyze equilibrium adsorption data include the Langmuir and Freundlich models (Khayyun & Mseer 2019).

Langmuir is one of the most prominent isotherm models that describe the nonlinear equilibrium between the amount of adsorbed analyte and its free amount in solution at a constant temperature. This model is simple and provides a good description of the experimental behavior in a wide range of working conditions. This isotherm is based on the assumption of monolayer adsorption on an adsorbent with a homogeneous structure that all adsorption sites are the same and equal in energy. The Langmuir relationship is expressed as follows (Mustapha et al. 2019):
formula
(3)
or in linear form (Equation (4));
formula
(4)

In Equation (4), qe is the amount of adsorbed analyte per unit mass of the adsorbent and qmax is the maximum amount of adsorption in the adsorbent monolayer in mg/g, Ce is the equilibrium concentration of the analyte in solution in mg/L, and KL is the Langmuir equation constant.

The Freundlich adsorption model (Equation (5)) is an empirical relation which indicates that adsorption takes place in multiple layers (Na 2020).
formula
(5)
or in the linear form as follows;
formula
(6)
where n is a constant related to the heterogeneity of the surface, and its value usually varies in the range of 0–1. The closer value of n to 1 means the more homogeneous surface. KF is the Freundlich constant that is related to the adsorption capacity. The Freundlich model shows that a higher concentration of initial analyte would lead to a higher adsorption rate of nanoparticles.
Hall et al. (1966) introduced the dimensionless component RL, called the separation coefficient. This component is used to describe the type and shape of the adsorption isotherm. It is expressed as Equation (7), and the relationship of RL with the type of Langmuir isotherm is shown in Table 2.
formula
(7)
where C0 is the initial adsorbed concentration in solution (mg/L), and KL is the Langmuir equation constant. The Langmuir model is obtained by assuming that the adsorption energy is constant for the active positions of the adsorbent surface and does not depend on its coverage.

The Freundlich model assumes that the number of positions in the adsorption action with free energy can be potentially reduced by increasing free energy (Shikuku et al. 2018). According to this assumption, with an increasing solute concentration in the solution, the surface concentration never reaches saturation due to high free energy surface sites for adsorption. The value of n in Equation (5) describes the type of the Freundlich isotherm. The type of relationship is given in Table 3 (Santhy & Selvapathy 2006).

Table 3

Correlation n with the Freundlich isotherm

Isotherm situationn
Undesirable n > 1 
Linear n = 1 
Desired n < 1 
Isotherm situationn
Undesirable n > 1 
Linear n = 1 
Desired n < 1 

DISCUSSION

As was mentioned previously, there are many techniques for eliminating dye contaminants from wastewater. All of these different methods of color removal have the advantages and disadvantages as shown in Table 4.

Table 4

An overview of the advantages and disadvantages of dye removal methods (Robinson et al. 2001; Salleh et al. 2011)

MethodAdvantagesDisadvantages
Chemical purification 
 Oxidation Ease of use Requires activation agent 
 H2O2 + Fe (II) salts Suitable for removal Sludge production 
 Ozonation It can be used in the form of ozone and does not increase the volume of sludge and effluent Short half-life (20 min) 
Biological treatment 
 Decolorization by white-rot fungus Enzymatic removal of dyes is performed Enzyme production is unreliable 
 Microbial mixture Removal in 24–30 h Azo dyes are not easily metabolized under aerobic conditions 
 Adsorption by living or dead biomass Specific colors have a special tendency to bind to microbial species No effect for all colors 
 Anaerobic bioremediation of textile dyes Makes it possible to remove azo and water-soluble dyes Anaerobic decomposition produces methane and hydrogen sulfide 
Physical purification 
 Adsorption with carbon Perfect removal of a wide range of colors High cost 
 Membrane filtration All of dyes removed Production of concentrated sludge 
 Ion exchange Rehabilitation: no loss of adsorbent No effect for all colors 
 Irradiation Effective oxidation on a laboratory scale Requires high levels of soluble O2 
 Electrochemical coagulation Economically flexible High volume of sludge production 
MethodAdvantagesDisadvantages
Chemical purification 
 Oxidation Ease of use Requires activation agent 
 H2O2 + Fe (II) salts Suitable for removal Sludge production 
 Ozonation It can be used in the form of ozone and does not increase the volume of sludge and effluent Short half-life (20 min) 
Biological treatment 
 Decolorization by white-rot fungus Enzymatic removal of dyes is performed Enzyme production is unreliable 
 Microbial mixture Removal in 24–30 h Azo dyes are not easily metabolized under aerobic conditions 
 Adsorption by living or dead biomass Specific colors have a special tendency to bind to microbial species No effect for all colors 
 Anaerobic bioremediation of textile dyes Makes it possible to remove azo and water-soluble dyes Anaerobic decomposition produces methane and hydrogen sulfide 
Physical purification 
 Adsorption with carbon Perfect removal of a wide range of colors High cost 
 Membrane filtration All of dyes removed Production of concentrated sludge 
 Ion exchange Rehabilitation: no loss of adsorbent No effect for all colors 
 Irradiation Effective oxidation on a laboratory scale Requires high levels of soluble O2 
 Electrochemical coagulation Economically flexible High volume of sludge production 

Fenton reaction, electrochemical method, oxidation, photochemical, UV degradation method, ozonation, or advanced oxidation process are typical processes used for dye removal based on the chemical method. Chemical methods are not commercially favorable due to specific equipment and high electrical energy compared to physical and biological methods. Besides, utilizing the chemical techniques can lead to additional environmental problems due to the consumption of huge amounts of chemicals and releasing of probable toxic material due to chemical reactions (Katheresan et al. 2018).

As typical examples, several works studied dye removal, such as low-cost adsorbents for the removal of organic pollutants from industrial wastewater by Ali et al. (2012), adsorption of cationic and anionic dyes by agricultural solid wastes by Salleh et al. (2011), unconventional low-cost adsorbents for dye removal by Crini (2006), decolorization of effluent dye by biosorbents by Srinivasan & Viraraghavan (2010), biodegradation of industrial dyes by Ali (2010), and adsorption of aqueous methylene on low-cost adsorbents by Rafatullah et al. (2010). However, all are shared only with a specific system and have nothing to do with updated information.

The effects of pH on the dye adsorption from different solutions are given in Table 5.

Table 5

Results of various studies to determine the effect of pH on the adsorption process

AdsorbentDyepH rangeRemoval range (%)References
Modified alumina Crystal violet 2.6–10.8 20–80 Adak et al. (2005)  
Activated carbon Methylene blue 2–11 Additive Kannan & Sundaram (2001)  
Kaolinite Crystal violet 2–7 65–95 Nandi et al. (2008)  
Bentonite Blue acid 193 1.5–11 Decrease Sarı et al. (2019)  
Fly ash Methylene blue 2–8 36–45 Kumar et al. (2005)  
Fe2O3 Red acid 27 1.5–10.5 27–98 Nassar (2010)  
Tobacco Methylene blue 2–7.93 60–81 Ghosh & Reddy (2013)  
Modified sawdust Methylene blue 2–11 Additive Zou et al. (2013)  
AdsorbentDyepH rangeRemoval range (%)References
Modified alumina Crystal violet 2.6–10.8 20–80 Adak et al. (2005)  
Activated carbon Methylene blue 2–11 Additive Kannan & Sundaram (2001)  
Kaolinite Crystal violet 2–7 65–95 Nandi et al. (2008)  
Bentonite Blue acid 193 1.5–11 Decrease Sarı et al. (2019)  
Fly ash Methylene blue 2–8 36–45 Kumar et al. (2005)  
Fe2O3 Red acid 27 1.5–10.5 27–98 Nassar (2010)  
Tobacco Methylene blue 2–7.93 60–81 Ghosh & Reddy (2013)  
Modified sawdust Methylene blue 2–11 Additive Zou et al. (2013)  

Chowdhury et al. (2011) studied the effect of pH of the solution on the adsorption of four green colors by Ananas comosus leaf powder. They found that at a pH range of 2–10, the maximum dye removal rate was at pH = 10. Dawood & Sen (2012) studied the effect of pH on the adsorption of red Congo dye by pine cones and found that the maximum adsorption occurs at pH = 3.5. Ibrahim et al. (2010) studied the adsorption of RB4 dye by modified barley straw. They found that the complete removal of RB4 occurred at pH = 3, and with increasing pH, the amount of adsorption decreased to less than 50%. Yagub et al. (2012) reported that cationic MB's adsorption on pine leaves increases with pH increasing.

According to Table 5, almost all of the adsorbent performance in dye removal has been enhanced by increasing pH. Typically, crystal violet removal utilizing modified alumina has 60% increased by increasing pH from 2.6 to 10.8, while this manner is almost repeated for other adsorbents. The increase of H+ ion concentration may lead to a higher protonation degree of the adsorbent surface, which leads to an increase in the electrostatic interaction between the adsorbent and the dye with a negative charge. A higher interaction between the dye molecule and the adsorbent surface leads to a higher adsorption rate. However, increasing OH group concentration on the adsorbent surface (deprotonated surface) in a high pH would lead to a lower adsorption rate (Wong et al. 2020), leading to a more inferior adsorption rate dye in high pH conditions. The pH variation may affect the transport of dye molecules to the surface of the adsorbent, which can be considered as the rate-limiting stage in the dye adsorption process (Saratale et al. 2011).

As can be seen in Table 6, the increment of the initial dye concentration leads to an increase in dye removal by implementing all presented adsorbents, while as a typical example, methylene blue removal over kaolinite, pine leaves, or mango kernel powder has increased from 62, 41, and 92.5% to 90, 96, and 99%, respectively. The presence of more dye initial concentrations leads to the increase of dye molecules in constant adsorbent amounts, resulting in higher dye removal and adsorption capacity. Moreover, due to the saturation of adsorbent sites, the remained dye molecules in the solution do not adsorb on the adsorbent. Zhang et al. (2012) studied the adsorption of methyl orange by chitosan/alumina. The results of their study showed that when the concentration of methyl orange increased from 20 to 400 mg/L, the percentage of dye removal decreased from 99.53 to 83.55%. Yagub et al. (2012) studied the effect of initial dye concentration on the adsorption of methylene (MB) blue from pine trees. They found that the color decreased from 96.5 to 40.9% in 240 min.

Table 6

Results of various studies in determining the effect of initial dye concentration on the adsorption process

AdsorbentDyeConcentration range (mg·L−1)Removal range (%)References
Kaolinite Methylene blue 10–40 62–90 Motamedi et al. (2011)  
Fly ash Red Congo 5–30 84–99 Mall et al. (2005)  
Red clay Purple acid 10–40 12.52–26.2 Namasivayam et al. (2001)  
Activated carbon Ariochrome block T 30–150 10–45 Luna et al. (2013)  
Mango kernel powder Methylene blue 50–250 92.5–99 Senthil Kumar et al. (2013); Anitha et al. (2016)  
Pine leaves Methylene blue 10–90 41–96 Ramaraju et al. (2013)  
Rice husk Green Malachite 10–30 71–82.5 Kahraman et al. (2011)  
Apricot kernels Black Astrazone 50–500 62–91 Argun et al. (2008)  
AdsorbentDyeConcentration range (mg·L−1)Removal range (%)References
Kaolinite Methylene blue 10–40 62–90 Motamedi et al. (2011)  
Fly ash Red Congo 5–30 84–99 Mall et al. (2005)  
Red clay Purple acid 10–40 12.52–26.2 Namasivayam et al. (2001)  
Activated carbon Ariochrome block T 30–150 10–45 Luna et al. (2013)  
Mango kernel powder Methylene blue 50–250 92.5–99 Senthil Kumar et al. (2013); Anitha et al. (2016)  
Pine leaves Methylene blue 10–90 41–96 Ramaraju et al. (2013)  
Rice husk Green Malachite 10–30 71–82.5 Kahraman et al. (2011)  
Apricot kernels Black Astrazone 50–500 62–91 Argun et al. (2008)  

However, based on the data as shown in Table 7, adsorbents such as kaolinite or Na-bentonite exhibit exothermic adsorption, while other adsorbents in Table 7 show an endothermic process. Presented adsorption results for kaolinite and Na-bentonite indicate a slight adsorption decline of Red Congo by increasing temperature from 279 to 333 K, so must a low-temperature condition be considered for Red Congo adsorption on the kaolinite and Na-bentonite. Additionally, exothermic adsorption of Red Congo over kaolinites and Na-bentonite was approved by the exhibited negative enthalpy (ΔH) values from −15.25 KJ·mol−1 at 279 K to −15.532 KJ·mol−1 at 333 K. On the other hand, other adsorbents exhibit an endothermic adsorption process, in which adsorption capacities have increased by an increase in temperature for pine leaves, activated bamboo water, and residual sludge adsorbents. Typically, methylene blue adsorption over pine leaves has grown at a higher temperature, indicating endothermic adsorption of methylene blue over pine leaves. Besides, exhibited positive enthalpy (15.29 KJ·mol−1) confirms the endothermic process of methylene blue.

Table 7

Results of various studies to determine the effect of temperature on dye adsorption

AdsorbentDyeTemperature range (K)ProcessReferences
Kaolinite Red Congo 279–333 Exothermic Vimonses et al. (2009)  
Na-Bentonite Red Congo 279–333 Exothermic Vimonses et al. (2009)  
Pine leaves Methylene blue 313–333 Endothermic Yagub et al. (2012)  
Activated bamboo waste Reactive black 5 303–323 Endothermic Ahmad et al. (2013)  
Residual sludge Green Naphthol 303–323 Endothermic Attallah et al. (2012)  
AdsorbentDyeTemperature range (K)ProcessReferences
Kaolinite Red Congo 279–333 Exothermic Vimonses et al. (2009)  
Na-Bentonite Red Congo 279–333 Exothermic Vimonses et al. (2009)  
Pine leaves Methylene blue 313–333 Endothermic Yagub et al. (2012)  
Activated bamboo waste Reactive black 5 303–323 Endothermic Ahmad et al. (2013)  
Residual sludge Green Naphthol 303–323 Endothermic Attallah et al. (2012)  

According to Table 8, in the presence of higher concentrations of adsorbents the dye removal was increased. By increasing the pine cone adsorbent amount from 0.01 to 0.03 g, Red Congo dye removal has grown from 13.45 to 18.96, while this manner was observed for all mentioned adsorbents. As discussed above, the higher dosage of adsorbent would lead to higher vacant sites availability, so more dye molecules can contact adsorbent active sites that lead to higher dye removal. Additionally, by an increase in the amount of adsorbent, a higher surface area (micropore or mesopore structures) may be available. This higher surface area enables the adsorbent to operate with a higher capacity in dye adsorption (Mall et al. 2005).

Table 8

Results of studies performed to determine the effect of adsorbent on removal percentage

AdsorbentDyeAmount of adsorbentRemoval percentage (%)References
Pine cone Red Congo 0.01–0.03 mg 13.45–18.96 Dawood & Sen (2012)  
Fly ash Methylene blue 8,000–20,000 mg 45–96 Kumar et al. (2005)  
Tea residual Basic yellow 2.20 g·L−1 19–60 Khosla et al. (2013)  
Orange peel Purple acid 50–600 mg/50 mL 15–98 Sivaraj et al. (2001)  
Rice husk Orange reactive 20–80 mg 21.7–56.2 Ong et al. (2007)  
Refined sawdust Green Malachite 200–1,000 mg/100 mL 18.60–86.90 Garg et al. (2003)  
AdsorbentDyeAmount of adsorbentRemoval percentage (%)References
Pine cone Red Congo 0.01–0.03 mg 13.45–18.96 Dawood & Sen (2012)  
Fly ash Methylene blue 8,000–20,000 mg 45–96 Kumar et al. (2005)  
Tea residual Basic yellow 2.20 g·L−1 19–60 Khosla et al. (2013)  
Orange peel Purple acid 50–600 mg/50 mL 15–98 Sivaraj et al. (2001)  
Rice husk Orange reactive 20–80 mg 21.7–56.2 Ong et al. (2007)  
Refined sawdust Green Malachite 200–1,000 mg/100 mL 18.60–86.90 Garg et al. (2003)  

It is important to regenerate the adsorbent and reuse it in the adsorption process to make the adsorption process more economical. Almost all of the adsorbents have been regenerated by chemical agents such as NaOH or HCl. In most cases, the regenerated adsorbent was suitable for the color adsorption process for at least three cycles; however, the reusability of the adsorbents may decline after several regeneration cycles. According to Table 9, all mentioned adsorbents show proper reusability after that regenerated by a chemical treatment (e.g., HCl or NaOH). However, adsorbent activity may decline after several cycles of regeneration due to part structure collapse or remaining adsorbed molecule in adsorbent structure (Fan et al. 2018).

Table 9

Regeneration of adsorbents implemented for dye removal

AdsorbentDye nameRegeneration agentReuse cycleReferences
Activated pinecone Alizarin Red S NaOH Bhomick et al. (2018)  
Magnetic rice husk Methylene blue NaOH 10 Lawagon & Amon (2019)  
Chitosan Reactive black 5 NaOH Vakili et al. (2019)  
Chitosan/bentonite/CTAB Weak acid scarlet NaOH Vakili et al. (2019)  
Activated bentonite/alginate Methylene blue HCl Aichour & Zaghouane-Boudiaf (2020)  
Fe3O4/activated charcoal/-cyclodextrin/alginate Methylene blue HCl Yadav et al. (2020)  
Modified activated carbon Methylene blue HCl Naushad et al. (2019)  
AdsorbentDye nameRegeneration agentReuse cycleReferences
Activated pinecone Alizarin Red S NaOH Bhomick et al. (2018)  
Magnetic rice husk Methylene blue NaOH 10 Lawagon & Amon (2019)  
Chitosan Reactive black 5 NaOH Vakili et al. (2019)  
Chitosan/bentonite/CTAB Weak acid scarlet NaOH Vakili et al. (2019)  
Activated bentonite/alginate Methylene blue HCl Aichour & Zaghouane-Boudiaf (2020)  
Fe3O4/activated charcoal/-cyclodextrin/alginate Methylene blue HCl Yadav et al. (2020)  
Modified activated carbon Methylene blue HCl Naushad et al. (2019)  

CONCLUSION AND FUTURE PERSPECTIVES

In this study, a series of adsorbents such as industrial solids, agricultural by-products, activated carbon, activated carbon-based biomasses, nano-adsorbents, mineral oxides, and mineral soil are reviewed to remove dye or contaminants from aqueous solutions. Adsorbents should be available, cost-effective, porous, recyclable, and have many active sites on their structure. In this way, future studies could focus on the adsorbents with good adsorption/desorption performance, recyclability, and cost-effectiveness. Furthermore, finding cost-effective strategies in the fields of storage and reusability of used adsorbents are other important issues for the future studies. In this way, the safe and economical disposal/reuse of used adsorbents should be considered in future investigations. It is possible to use raw materials and refining materials instead of expensive commercial activated carbon to remove dye from aqueous solutions. In this review study, a large number of articles have been reviewed, and as can be seen, the mechanism and methods of adsorption for the removal of contaminants by the adsorbent depend on the conditions of experimental physical and chemical data such as pH, initial contaminant concentration, adsorbent concentration, and temperature. In this review study, it is found that the Langmuir and Freundlich adsorption isotherm models for measuring the adsorption capacity of adsorbents are different, and the kinetic data for the adsorption of color pollutants usually follow the pseudo-second-order kinetic model.

CONFLICT OF INTEREST

The authors declare that they have no conflict of interest.

FUNDING

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

DATA AVAILABILITY STATEMENT

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

REFERENCES

Abdi
G.
,
Alizadeh
A.
,
Zinadini
S.
&
Moradi
G.
2018
Removal of dye and heavy metal ion using a novel synthetic polyethersulfone nanofiltration membrane modified by magnetic graphene oxide/metformin hybrid
.
Journal of Membrane Science
552
,
326
335
.
https://doi.org/10.1016/J.MEMSCI.2018.02.018
.
Adak
A.
,
Bandyopadhyay
M.
&
Pal
A.
2005
Removal of crystal violet dye from wastewater by surfactant-modified alumina
.
Separation and Purification Technology
44
(
2
),
139
144
.
https://doi.org/10.1016/j.seppur.2005.01.002
.
Adegoke
K. A.
&
Bello
O. S.
2015
Dye sequestration using agricultural wastes as adsorbents
.
Water Resources and Industry
12
,
8
24
.
https://doi.org/10.1016/j.wri.2015.09.002
.
Ahmad
A. A.
,
Idris
A.
&
Hameed
B. H.
2013
Organic Dye adsorption on activated carbon derived from solid waste
.
Desalination and Water Treatment
51
(
13–15
),
2554
2563
.
https://doi.org/10.1080/19443994.2012.749019
.
Aichour
A.
&
Zaghouane-Boudiaf
H.
2020
Synthesis and characterization of hybrid activated bentonite/alginate composite to improve its effective elimination of dyes stuff from wastewater
.
Applied Water Science
10
(
6
).
https://doi.org/10.1007/s13201-020-01232-0
.
Ali
H.
2010
Biodegradation of synthetic dyes – a review
.
Water, Air, & Soil Pollution
213
(
1–4
),
251
273
.
https://doi.org/10.1007/s11270-010-0382-4
.
Ali
I.
2013
Water treatment by adsorption columns: evaluation at ground level
.
Separation & Purification Reviews
43
(
3
),
175
205
.
https://doi.org/10.1080/15422119.2012.748671
.
Ali
I.
,
Asim
M.
&
Khan
T. A.
2012
Low cost adsorbents for the removal of organic pollutants from wastewater
.
Journal of Environmental Management
113
,
170
183
.
https://doi.org/10.1016/j.jenvman.2012.08.028
.
Al-Sakkaf
B. M.
,
Nasreen
S.
&
Ejaz
N.
2020
Degradation pattern of textile effluent by using bio and sono chemical reactor
.
Journal of Chemistry
2020
,
1
13
.
https://doi.org/10.1155/2020/8965627
.
Anitha
T.
,
Senthil Kumar
P.
,
Sathish Kumar
K.
,
Sriram
K.
&
Ahmed
J. F.
2016
Biosorption of lead(II) ions onto nano-sized chitosan particle blended polyvinyl alcohol (PVA): adsorption isotherms, kinetics and equilibrium studies
.
Desalination and Water Treatment
57
(
29
),
13711
13721
.
doi:10.1080/19443994.2015.1061951
.
Argun
M. E.
,
Dursun
S.
,
Karatas
M.
&
Gürü
M.
2008
Activation of pine cone using Fenton oxidation for Cd(II) and Pb(II) removal
.
Bioresource Technology
99
(
18
),
8691
8698
.
https://doi.org/10.1016/j.biortech.2008.04.014
.
Attallah
M. F.
,
Ahmed
I. M.
&
Hamed
M. M.
2012
Treatment of industrial wastewater containing Congo Red and Naphthol Green B using low-cost adsorbent
.
Environmental Science and Pollution Research
20
(
2
),
1106
1116
.
https://doi.org/10.1007/s11356-012-0947-4
.
Badran
I.
&
Khalaf
R.
2019
Adsorptive removal of alizarin dye from wastewater using maghemite nanoadsorbents
.
Separation Science and Technology
55
(
14
),
2433
2448
.
https://doi.org/10.1080/01496395.2019.1634731
.
Belhamdi
B.
,
Merzougui
Z.
,
Trari
M.
&
Addoun
A.
2016
A kinetic, equilibrium and thermodynamic study of l-phenylalanine adsorption using activated carbon based on agricultural waste (date stones)
.
Journal of Applied Research and Technology
14
(
5
),
354
366
.
https://doi.org/10.1016/j.jart.2016.08.004
.
Benkhaya
S.
,
M'rabet
S.
&
Harfi
A. E.
2020
Classifications, properties, recent synthesis and applications of azo dyes
.
Heliyon
6
(
1
),
e03271
.
https://doi.org/10.1016/j.heliyon.2020.e03271
.
Bhomick
P. C.
,
Supong
A.
,
Baruah
M.
,
Pongener
C.
&
Sinha
D.
2018
Pine cone biomass as an efficient precursor for the synthesis of activated biocarbon for adsorption of anionic dye from aqueous solution: isotherm, kinetic, thermodynamic and regeneration studies
.
Sustainable Chemistry and Pharmacy
10
,
41
49
.
https://doi.org/10.1016/j.scp.2018.09.001
.
Briton
B. G. H.
,
Yao
B. K.
,
Richardson
Y.
,
Duclaux
L.
,
Reinert
L.
&
Soneda
Y.
2020
Optimization by using response surface methodology of the preparation from plantain spike of a micro-/mesoporous activated carbon designed for removal of dyes in aqueous solution
.
Arabian Journal for Science and Engineering
45
(
9
),
7231
7245
.
https://doi.org/10.1007/s13369-020-04390-0
.
Chakraborty
R.
,
Asthana
A.
,
Singh
A. K.
,
Jain
B.
&
Susan
A. B. H.
2020
Adsorption of heavy metal ions by various low-cost adsorbents: a review
.
International Journal of Environmental Analytical Chemistry
,
1
38
.
https://doi.org/10.1080/03067319.2020.1722811
.
Chowdhury
S.
,
Chakraborty
S.
&
Saha
P.
2011
Biosorption of Basic Green 4 from aqueous solution by Ananas comosus (Pineapple) leaf powder
.
Colloids and Surfaces B: Biointerfaces
84
(
2
),
520
527
.
https://doi.org/10.1016/j.colsurfb.2011.02.009
.
Crini
G.
2006
Non-conventional low-cost adsorbents for dye removal: a review
.
Bioresource Technology
97
(
9
),
1061
1085
.
https://doi.org/10.1016/j.biortech.2005.05.001
.
Dayı
B.
,
Onac
C.
,
Kaya
A.
,
Akdogan
H. A.
&
Rodriguez-Couto
S.
2020
New type biomembrane: transport and biodegradation of reactive textile dye
.
ACS Omega
5
(
17
),
9813
9819
.
https://doi.org/10.1021/acsomega.9b04433
.
Elwakeel
K. Z.
,
Elgarahy
A. M.
,
Elshoubaky
G. A.
&
Mohammad
S. H.
2020
Microwave assist sorption of crystal violet and Congo Red dyes onto amphoteric sorbent based on upcycled sepia shells
.
Journal of Environmental Health Science & Engineering
18
(
1
),
35
50
.
https://doi.org/10.1007/s40201-019-00435-1
.
Fan
B.-G.
,
Jia
L.
,
Wang
Y.-L.
,
Zhao
R.
,
Mei
X.-S.
,
Liu
Y.-Y.
&
Jin
Y.
2018
Study on adsorption mechanism and failure characteristics of CO2 adsorption by potassium-based adsorbents with different supports
.
Materials
11
(
12
),
2424
.
https://doi.org/10.3390/ma11122424
.
Garg
V. K.
,
Gupta
R.
,
Yadav
A. B.
&
Kumar
R.
2003
Dye removal from aqueous solution by adsorption on treated sawdust
.
Bioresource Technology
89
(
2
),
121
124
.
https://doi.org/10.1016/s0960-8524(03)00058-0
.
Ghoreishi
S. M.
&
Haghighi
R.
2003
Chemical catalytic reaction and biological oxidation for treatment of non-biodegradable textile effluent
.
Chemical Engineering Journal
95
(
1–3
),
163
169
.
https://doi.org/10.1016/s1385-8947(03)00100-1
.
Ghosh
R. K.
&
Damodar Reddy
D.
2013
Tobacco stem ash as an adsorbent for removal of methylene blue from aqueous solution: equilibrium, kinetics, and mechanism of adsorption
.
Water, Air, & Soil Pollution
224
(
6
).
https://doi.org/10.1007/s11270-013-1582-5
.
Hajipour
F.
,
Asad
S.
,
Amoozegar
M. A.
,
Javidparvar
A. A.
,
Tang
J.
,
Zhong
H.
&
Khajeh
K.
2021
Developing a fluorescent hybrid nanobiosensor based on quantum dots and azoreductase enzyme for methyl red monitoring
.
Iranian Biomedical Journal
25
(
1
).
https://doi.org/10.29252/ibj.25.1.8
.
Hall
K. R.
,
Eagleton
L. C.
,
Acrivos
A.
&
Vermeulen
T.
1966
Pore- and solid-diffusion kinetics in fixed-bed adsorption under constant-pattern conditions
.
Industrial & Engineering Chemistry Fundamentals
5
(
2
),
212
223
.
https://doi.org/10.1021/i160018a011
.
Hou
M.-F.
,
Liao
L.
,
Zhang
W.-D.
,
Tang
X.-Y.
,
Wan
H.-F.
&
Yin
G.-C.
2011
Degradation of rhodamine B by Fe(0)-based Fenton process with H2O2
.
Chemosphere
83
(
9
),
1279
1283
.
https://doi.org/10.1016/j.chemosphere.2011.03.005
.
Hynes
N. R. J.
,
Senthil Kumar
J.
,
Kamyab
H.
,
Angela Jennifa Sujana
J.
,
Al-Khashman
O. A.
,
Kuslu
Y.
,
Ene
A.
&
Suresh Kumar
B.
2020
Modern enabling techniques and adsorbents based dye removal with sustainability concerns in textile industrial sector – a comprehensive review
.
Journal of Cleaner Production
272
,
122636
.
https://doi.org/10.1016/j.jclepro.2020.122636
.
Ibrahim
S.
,
Fatimah
I.
,
Ang
H.-M.
&
Wang
S.
2010
Adsorption of anionic dyes in aqueous solution using chemically modified barley straw
.
Water Science and Technology
62
(
5
),
1177
1182
.
https://doi.org/10.2166/wst.2010.388
.
Javaid
R.
&
Qazi
U. Y.
2019
Catalytic oxidation process for the degradation of synthetic dyes: an overview
.
International Journal of Environmental Research and Public Health
16
(
11
),
2066
.
https://doi.org/10.3390/ijerph16112066
.
Javidparvar
A. A.
,
Naderi
R.
&
Ramezanzadeh
B.
2020
Non-covalently surface modification of graphene oxide nanosheets and its role in the enhancement of the epoxy-based coatings’ physical properties
.
Colloids and Surfaces A: Physicochemical and Engineering Aspects
602
,
125061
.
https://doi.org/10.1016/J.COLSURFA.2020.125061
.
Jiang
L.-l.
,
Yu
H.-T.
,
Pei
L.-f.
&
Hou
X.-g.
2018
The effect of temperatures on the synergistic effect between a magnetic field and functionalized graphene oxide-carbon nanotube composite for Pb2+ and phenol adsorption
.
Journal of Nanomaterials
2018
,
1
13
.
https://doi.org/10.1155/2018/9167938
.
Jouniaux
L.
&
Ishido
T.
2012
Electrokinetics in earth sciences: a tutorial
.
International Journal of Geophysics
2012
,
1
16
.
https://doi.org/10.1155/2012/286107
.
Julkapli
M.
,
Nurhidayatullaili
S. B.
&
Hamid
S. B. A.
2014
Recent advances in heterogeneous photocatalytic decolorization of synthetic dyes
.
The Scientific World Journal
2014
,
692307
.
https://doi.org/10.1155/2014/692307
.
Kahraman
S.
,
Yalcin
P.
&
Kahraman
H.
2011
The evaluation of low-cost biosorbents for removal of an azo dye from aqueous solution
.
Water and Environment Journal
26
(
3
),
399
404
.
https://doi.org/10.1111/j.1747-6593.2011.00300.x
.
Kannan
N.
&
Sundaram
M. M.
2001
Kinetics and mechanism of removal of methylene blue by adsorption on various carbons – a comparative study
.
Dyes and Pigments
51
(
1
),
25
40
.
https://doi.org/10.1016/s0143-7208(01)00056-0
.
Karim
Z.
,
Mathew
A. P.
,
Grahn
M.
,
Mouzon
J.
&
Oksman
K.
2014
Nanoporous membranes with cellulose nanocrystals as functional entity in chitosan: removal of dyes from water
.
Carbohydrate Polymers
112
,
668
676
.
https://doi.org/10.1016/J.CARBPOL.2014.06.048
.
Katheresan
V.
,
Kansedo
J.
&
Lau
S. Y.
2018
Efficiency of various recent wastewater dye removal methods: a review
.
Journal of Environmental Chemical Engineering
6
(
4
),
4676
4697
.
https://doi.org/10.1016/j.jece.2018.06.060
.
Khayyun
T. S.
&
Mseer
A. H.
2019
Comparison of the experimental results with the Langmuir and Freundlich models for copper removal on limestone adsorbent
.
Applied Water Science
9
(
8
).
https://doi.org/10.1007/s13201-019-1061-2
.
Khosla
E.
,
Kaur
S.
&
Dave
P. N.
2013
Tea waste as adsorbent for ionic dyes
.
Desalination and Water Treatment
51
(
34–36
),
6552
6561
.
https://doi.org/10.1080/19443994.2013.791776
.
Khulbe
K. C.
&
Matsuura
T.
2018
Removal of heavy metals and pollutants by membrane adsorption techniques
.
Applied Water Science
8
(
1
).
https://doi.org/10.1007/s13201-018-0661-6
.
Konicki
W.
,
Aleksandrzak
M.
,
Moszyński
D.
&
Mijowska
E.
2017
Adsorption of anionic azo-dyes from aqueous solutions onto graphene oxide: equilibrium, kinetic and thermodynamic studies
.
Journal of Colloid and Interface Science
496
,
188
200
.
https://doi.org/10.1016/J.JCIS.2017.02.031
.
Kosaka
K.
,
Iwatani
A.
,
Takeichi
Y.
,
Yoshikawa
Y.
,
Ohkubo
K.
&
Akiba
M.
2018
Removal of haloacetamides and their precursors at water purification plants applying ozone/biological activated carbon treatment
.
Chemosphere
198
,
68
74
.
https://doi.org/10.1016/J.CHEMOSPHERE.2018.01.093
.
Kumar
K. V.
,
Ramamurthi
V.
&
Sivanesan
S.
2005
Modeling the mechanism involved during the sorption of methylene blue onto fly ash
.
Journal of Colloid and Interface Science
284
(
1
),
14
21
.
https://doi.org/10.1016/j.jcis.2004.09.063
.
Kumar
P.
,
Agnihotri
R.
,
Wasewar
K. L.
,
Uslu
H.
&
Yoo
C.
2012
Status of adsorptive removal of dye from textile industry effluent
.
Desalination and Water Treatment
50
(
1–3
),
226
244
.
https://doi.org/10.1080/19443994.2012.719472
.
Kumar
H.
,
Maurya
K. L.
,
Gehlaut
A. K.
,
Singh
D.
,
Maken
S.
,
Gaur
A.
&
Kamsonlian
S.
2019
Adsorptive removal of chromium(VI) from aqueous solution using binary bio-polymeric beads made from bagasse
.
Applied Water Science
10
,
1
.
https://doi.org/10.1007/s13201-019-1101-y
.
Lawagon
C. P.
&
Amon
R. E. C.
2019
Magnetic rice husk Ash ‘cleanser’ as efficient methylene blue adsorbent
.
Environmental Engineering Research
25
(
5
),
685
692
.
https://doi.org/10.4491/eer.2019.287
.
Lellis
B.
,
Fávaro-Polonio
C. Z.
,
Pamphile
J. A.
&
Polonio
J. C.
2019
Effects of textile dyes on health and the environment and bioremediation potential of living organisms
.
Biotechnology Research and Innovation
3
(
2
),
275
290
.
https://doi.org/10.1016/j.biori.2019.09.001
.
Luna
M. D. G. d.
,
Flores
E. D.
,
Genuino
D. A. D.
,
Futalan
C. M.
&
Wan
M.-W.
2013
Adsorption of Eriochrome Black T (EBT) dye using activated carbon prepared from waste rice hulls – optimization, isotherm and kinetic studies
.
Journal of the Taiwan Institute of Chemical Engineers
44
(
4
),
646
653
.
https://doi.org/10.1016/j.jtice.2013.01.010
.
Mall
I. D.
,
Srivastava
V. C.
,
Agarwal
N. K.
&
Mishra
I. M.
2005
Removal of Congo Red from aqueous solution by bagasse fly ash and activated carbon: kinetic study and equilibrium isotherm analyses
.
Chemosphere
61
(
4
),
492
501
.
https://doi.org/10.1016/j.chemosphere.2005.03.065
.
Misra
M.
,
Akansha
K.
,
Sachan
A.
&
Sachan
S. G.
2020
Removal of dyes from industrial effluents by application of combined biological and physicochemical treatment approaches
. In:
Combined Application of Physico-Chemical & Microbiological Processes for Industrial Effluent Treatment Plant
.
Springer
,
Singapore
.
https://doi.org/10.1007/978-981-15-0497-6_17
.
Mosbah
A.
,
Chouchane
H.
,
Abdelwahed
S.
,
Redissi
A.
,
Hamdi
M.
,
Kouidhi
S.
,
Neifar
M.
,
Masmoudi
A. S.
,
Cherif
A.
&
Mnif
W.
2019
Peptides fixing industrial textile dyes: a new biochemical method in wastewater treatment
.
Journal of Chemistry
2019
,
1
7
.
https://doi.org/10.1155/2019/5081807
.
Motamedi
M.
,
Tehrani-Bagha
A. R.
&
Mahdavian
M.
2011
A comparative study on the electrochemical behavior of mild steel in sulfamic acid solution in the presence of monomeric and gemini surfactants
.
Electrochimica Acta
58
,
488
496
.
https://doi.org/10.1016/j.electacta.2011.09.079
.
Mustapha
S.
,
Shuaib
D. T.
,
Ndamitso
M. M.
,
Etsuyankpa
M. B.
,
Sumaila
A.
,
Mohammed
U. M.
&
Nasirudeen
M. B.
2019
Adsorption isotherm, kinetic and thermodynamic studies for the removal of Pb(II), Cd(II), Zn(II) and Cu(II) ions from aqueous solutions using Albizia lebbeck pods
.
Applied Water Science
9
(
6
).
https://doi.org/10.1007/s13201-019-1021-x
.
Na
C.
2020
Size-controlled capacity and isocapacity concentration in Freundlich adsorption
.
ACS Omega
5
(
22
),
13130
13135
.
https://doi.org/10.1021/acsomega.0c01144
.
Namasivayam
C.
,
Yamuna
R.
&
Arasi
D.
2001
Removal of acid violet from wastewater by adsorption on waste Red Mud
.
Environmental Geology
41
(
3–4
),
269
273
.
https://doi.org/10.1007/s002540100411
.
Nandi
B. K.
,
Goswami
A.
,
Das
A. K.
,
Mondal
B.
&
Purkait
M. K.
2008
Kinetic and equilibrium studies on the adsorption of crystal violet dye using kaolin as an adsorbent
.
Separation Science and Technology
43
(
6
),
1382
1403
.
https://doi.org/10.1080/01496390701885331
.
Nassar
N. N.
2010
Kinetics, mechanistic, equilibrium, and thermodynamic studies on the adsorption of acid red dye from wastewater by γ-Fe2O3 nanoadsorbents
.
Separation Science and Technology
45
(
8
),
1092
1103
.
https://doi.org/10.1080/01496391003696921
.
Naushad
M.
,
Alqadami
A. A.
,
AlOthman
Z. A.
,
Alsohaimi
I. H.
,
Algamdi
M. S.
&
Aldawsari
A. M.
2019
Adsorption kinetics, isotherm and reusability studies for the removal of cationic Dye from aqueous medium using arginine modified activated carbon
.
Journal of Molecular Liquids
293
,
111442
.
https://doi.org/10.1016/j.molliq.2019.111442
.
Nelis
J. L. D.
,
Bura
L.
,
Zhao
Y.
,
Burkin
K. M.
,
Rafferty
K.
,
Elliott
C. T.
&
Campbell
K.
2019
The efficiency of color space channels to quantify color and color intensity change in liquids, PH strips, and lateral flow assays with smartphones
.
Sensors
19
(
23
),
5104
.
https://doi.org/10.3390/s19235104
.
Ong
S. T.
,
Lee
C. K.
&
Zainal
Z.
2007
Removal of basic and reactive dyes using ethylenediamine modified rice hull
.
Bioresource Technology
98
(
15
),
2792
2799
.
https://doi.org/10.1016/j.biortech.2006.05.011
.
Peng
X.
,
Yang
P.
,
Dai
K.
,
Chen
Y.
,
Chen
X.
,
Zhuang
W.
,
Ying
H.
&
Wu
J.
2020
Synthesis, adsorption and molecular simulation study of methylamine-modified hyper-cross-linked resins for efficient removal of citric acid from aqueous solution
.
Scientific Reports
10
(
1
),
9623
.
https://doi.org/10.1038/s41598-020-66592-8
.
Rafatullah
M.
,
Sulaiman
O.
,
Hashim
R.
&
Ahmad
A.
2010
Adsorption of methylene blue on low-cost adsorbents: a review
.
Journal of Hazardous Materials
177
(
1–3
),
70
80
.
https://doi.org/10.1016/j.jhazmat.2009.12.047
.
Rajasulochana
P.
&
Preethy
V.
2016
Comparison on efficiency of various techniques in treatment of waste and sewage water – a comprehensive review
.
Resource-Efficient Technologies
2
(
4
),
175
184
.
https://doi.org/10.1016/j.reffit.2016.09.004
.
Ramaraju
B.
,
Reddy
P. M. K.
&
Subrahmanyam
C.
2013
Low cost adsorbents from agricultural waste for removal of dyes
.
Environmental Progress & Sustainable Energy
33
(
1
),
38
46
.
https://doi.org/10.1002/ep.11742
.
Rápó
E.
,
Előd Aradi
L.
,
Szabó
Á.
,
Posta
K.
,
Szép
R.
&
Tonk
S.
2020
Adsorption of Remazol Brilliant Violet-5R textile dye from aqueous solutions by using eggshell waste biosorbent
.
Scientific Reports
10
(
1
),
8385
.
https://doi.org/10.1038/s41598-020-65334-0
.
Ray
S. S.
,
Gusain
R.
&
Kumar
N.
2020
Classification of water contaminants
. In:
Carbon Nanomaterial-Based Adsorbents for Water Purification
.
Elsevier
.
https://doi.org/10.1016/b978-0-12-821959-1.00002-7
.
Robinson
T.
,
McMullan
G.
,
Marchant
R.
&
Nigam
P.
2001
Remediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative
.
Bioresource Technology
77
(
3
),
247
255
.
https://doi.org/10.1016/s0960-8524(00)00080-8
.
Romdhane
D. F.
,
Satlaoui
Y.
,
Nasraoui
R.
,
Charef
A.
&
Azouzi
R.
2020
Adsorption, modeling, thermodynamic, and kinetic studies of methyl red removal from textile-polluted water using natural and purified organic matter rich clays as low-cost adsorbent
.
Journal of Chemistry
2020
,
1
17
.
https://doi.org/10.1155/2020/4376173
.
Salleh
M. A. M.
,
Mahmoud
D. K.
,
Karim
W. A. W. A.
&
Idris
A.
2011
Cationic and anionic dye adsorption by agricultural solid wastes: a comprehensive review
.
Desalination
280
(
1–3
),
1
13
.
https://doi.org/10.1016/j.desal.2011.07.019
.
Santhy
K.
&
Selvapathy
P.
2006
Removal of reactive dyes from wastewater by adsorption on coir pith activated carbon
.
Bioresource Technology
97
(
11
),
1329
1336
.
https://doi.org/10.1016/j.biortech.2005.05.016
.
Saratale
R. G.
,
Saratale
G. D.
,
Chang
J. S.
&
Govindwar
S. P.
2011
Bacterial decolorization and degradation of azo dyes: a review
.
Journal of the Taiwan Institute of Chemical Engineers
42
(
1
),
138
157
.
https://doi.org/10.1016/j.jtice.2010.06.006
.
Sarı
A.
,
Bicer
A.
,
Alkan
C.
&
Nazlı Özcan
A.
2019
Thermal energy storage characteristics of myristic acid-palmitic eutectic mixtures encapsulated in PMMA shell
.
Solar Energy Materials and Solar Cells
193
,
1
6
.
https://doi.org/10.1016/J.SOLMAT.2019.01.003
.
Sarkar
S.
,
Banerjee
A.
,
Halder
U.
,
Biswas
R.
&
Bandopadhyay
R.
2017
Degradation of synthetic azo dyes of textile industry: a sustainable approach using microbial enzymes
.
Water Conservation Science and Engineering
2
(
4
),
121
131
.
https://doi.org/10.1007/s41101-017-0031-5
.
Senthil Kumar
P.
,
Palaniyappan
M.
,
Priyadharshini
M.
,
Vignesh
A. M.
,
Thanjiappan
A.
,
Sebastina Anne Fernando
P.
,
Tanvir Ahmed
R.
&
Srinath
R.
2013
Adsorption of basic dye onto raw and surface-modified agricultural waste
.
Environmental Progress & Sustainable Energy
33
(
1
),
87
98
.
https://doi.org/10.1002/ep.11756
.
Shikuku
V. O.
,
Zanella
R.
,
Kowenje
C. O.
,
Donato
F. F.
,
Bandeira
N. M. G.
&
Prestes
O. D.
2018
Single and binary adsorption of sulfonamide antibiotics onto iron-modified clay: linear and nonlinear isotherms, kinetics, thermodynamics, and mechanistic studies
.
Applied Water Science
8
(
6
),
175
.
https://doi.org/10.1007/s13201-018-0825-4
.
Sivaraj
R.
,
Namasivayam
C.
&
Kadirvelu
K.
2001
Orange peel as an adsorbent in the removal of acid violet 17 (acid dye) from aqueous solutions
.
Waste Management
21
(
1
),
105
110
.
https://doi.org/10.1016/S0956-053X(00)00076-3
.
Skwarek
E.
,
Bolbukh
Y.
,
Tertykh
V.
&
Janusz
W.
2016
Electrokinetic properties of the pristine and oxidized MWCNT depending on the electrolyte type and concentration
.
Nanoscale Research Letters
11
(
1
),
166
.
https://doi.org/10.1186/s11671-016-1367-z
.
Son
D.
,
Hai
B.
,
Mai
V. Q.
,
Du
D. X.
,
Phong
N. H.
&
Khieu
D. Q.
2016
A study on Astrazon Black AFDL dye adsorption onto Vietnamese diatomite
.
Journal of Chemistry
2016
,
1
11
.
https://doi.org/10.1155/2016/8685437
.
Srinivasan
A.
&
Viraraghavan
T.
2010
Decolorization of dye wastewaters by biosorbents: a review
.
Journal of Environmental Management
91
(
10
),
1915
1929
.
https://doi.org/10.1016/J.JENVMAN.2010.05.003
.
Sulyman
M.
,
Namiesnik
J.
&
Gierak
A.
2017
Low-cost adsorbents derived from agricultural by-products/wastes for enhancing contaminant uptakes from wastewater: a review
.
Polish Journal of Environmental Studies
26
(
2
),
479
510
.
https://doi.org/10.15244/pjoes/66769
.
Vakili
M.
,
Deng
S.
,
Shen
L.
,
Shan
D.
,
Liu
D.
&
Yu
G.
2019
Regeneration of chitosan-based adsorbents for eliminating dyes from aqueous solutions
.
Separation & Purification Reviews
48
(
1
),
1
13
.
https://doi.org/10.1080/15422119.2017.1406860
.
Vimonses
V.
,
Lei
S.
,
Jin
B.
,
Chow
C. W. K.
&
Saint
C.
2009
Kinetic study and equilibrium isotherm analysis of Congo Red adsorption by clay materials
.
Chemical Engineering Journal
148
(
2–3
),
354
364
.
https://doi.org/10.1016/J.CEJ.2008.09.009
.
Wong
S.
,
Ghafar
N. A.
,
Ngadi
N.
,
Razmi
F. A.
,
Inuwa
I. M.
,
Mat
R.
&
Amin
N. A. S.
2020
Effective removal of anionic textile dyes using adsorbent synthesized from coffee waste
.
Scientific Reports
10
(
1
),
2928
.
https://doi.org/10.1038/s41598-020-60021-6
.
Yadav
S.
,
Asthana
A.
,
Chakraborty
R.
,
Jain
B.
,
Singh
A. K.
,
Carabineiro
S. A. C.
&
Susan
M. A. B. H.
2020
Cationic dye removal using novel magnetic/activated charcoal/β-cyclodextrin/alginate polymer nanocomposite
.
Nanomaterials
10
(
1
).
https://doi.org/10.3390/nano10010170
.
Yagub
M. T.
,
Sen
T. K.
&
Ang
H. M.
2012
Equilibrium, kinetics, and thermodynamics of methylene blue adsorption by pine tree leaves
.
Water, Air, & Soil Pollution
223
(
8
),
5267
5282
.
https://doi.org/10.1007/s11270-012-1277-3
.
Yu
L.
,
Chen
J.
,
Liang
Z.
,
Xu
W.
,
Chen
L.
&
Ye
D.
2016
Degradation of phenol using Fe3O4-GO nanocomposite as a heterogeneous photo-Fenton catalyst
.
Separation and Purification Technology
171
,
80
87
.
https://doi.org/10.1016/J.SEPPUR.2016.07.020
.
Zaied
B. K.
,
Rashid
M.
,
Nasrullah
M.
,
Zularisam
A. W.
,
Pant
D.
&
Singh
L.
2020
A comprehensive review on contaminants removal from pharmaceutical wastewater by electrocoagulation process
.
Science of the Total Environment
726
,
138095
.
https://doi.org/10.1016/J.SCITOTENV.2020.138095
.
Zhang
J.
,
Zhou
Q.
&
Ou
L.
2012
Kinetic, isotherm, and thermodynamic studies of the adsorption of methyl orange from aqueous solution by chitosan/alumina composite
.
Journal of Chemical & Engineering Data
57
(
2
),
412
419
.
https://doi.org/10.1021/je2009945
.
Zou
W.
,
Bai
H.
,
Gao
S.
&
Li
K.
2013
Characterization of modified sawdust, kinetic and equilibrium study about methylene blue adsorption in batch mode
.
Korean Journal of Chemical Engineering
30
(
1
),
111
122
.
https://doi.org/10.1007/s11814-012-0096-y
.
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