Water pollution from antibiotics has attracted a lot of attention for its serious threat to human health. In this study, a magnetic adsorbent (zinc ferrite/activated carbon (ZnFe2O4/AC) was synthesized via microwave method to effectively remove gemifioxacin mesylate (GEM) and moxifloxacin hydrochloride (MOX). Based on the porosity of AC and the magnetism of ZnFe2O4, the resulting ZnFe2O4/AC has high adsorption capacities and can be easily separated from the solid–liquid system via a magnetic field. The largest adsorption capacities for GEM and MOX can reach up to 433.4 mg g−1 and 388.8 mg g−1, respectively, higher than those of reported adsorbents such as MIL-101 and MOF-808. Fastest adsorptions of GEM and MOX were found at 5 min, and solution pH and coexisting salts do not have a significant influence on the adsorption process. The adsorption mechanism analysis indicates that electrostatic interaction and H-bond interaction contribute to the effective adsorption.

  • A magnetic adsorbent (zinc ferrite/activated carbon, ZnFe2O4/AC) with excellent porosity and magnetism was synthesized via microwave method.

  • The largest adsorption capacities for gemifioxacin mesylate and moxifloxacin hydrochloride can reach up to 433.4 mg g−1 and 388.8 mg g−1, respectively.

  • The adsorbent–adsorbate system can be easily separated via a magnetic field.

In recent years, quinolones have attracted extensive attention for their application in improving human health (Zhao et al. 2017). As two typical fourth-generation quinolone antibiotics (Blondeau & Tillotson 2008; Hammama et al. 2018), gemifioxacin mesylate (GEM) and moxifloxacin hydrochloride (MOX) were widely used in the treatment of acute sinusitis, genital tract infection, respiratory tract infection (Cheng et al. 2003; Hammama et al. 2018), and other diseases for their curative effect and slight side effects. However, excessive use of antibiotics resulted in them entering the water and soil, causing a serious threat to humans due to the negative effects on the immune system. Therefore, effective removal of antibiotics from aqueous solution has become an urgent problem.

In the past decades, several methods were developed to remove these pollutants, for example chlorination (Huber et al. 2005) and membrane filtration (Snyder et al. 2007) methods. However, these methods have the disadvantages of secondary pollution or limited application conditions. By comparison, the adsorption method has the advantages of easy operation, is low cost, highly efficiency, and does not produce highly toxic by-products (Kyzas et al. 2013). Accordingly, it has been considered as an effective method to remove pollutants from aqueous solution.

Activated carbon (AC), as a commonly used adsorbent, was used to treat industrial wastewater (Luo & Li 2019), but is not easily separated from the solution after adsorption during industrial operations. In this respect, magnetic materials were found to be of great potential. As a typical magnetic substance, zinc ferrite (ZnFe2O4) has attracted attention for its magnetic property (Yu et al. 2003; Konicki et al. 2017). In previous reports, AC was studied for its adsorption of organic pollutants, including antibiotics (Zhang et al. 2016; Fu et al. 2017; Ndagijimana et al. 2019). However, the magnetic composites of AC and ZnFe2O4 were rarely reported for removing antibiotics, especially for MOX and GEM. In this paper, ZnFe2O4 was prepared onto AC via microwave method to produce a novel composite, ZnFe2O4/AC. Based on characterization results, this composite was found to combine the porosity of AC and the magnetism of ZnFe2O4. As a result, ZnFe2O4/AC exhibited high adsorption capacities for the antibiotics (MOX and GEM). The drug-loaded adsorbent can also be quickly separated from aqueous solution by a magnetic field. The adsorption isotherm, adsorption kinetics, the effects of pH and coexisting salts were also studied.

Chemicals

Iron nitrate nonahydrate (Fe(NO3)3·9H2O, 99.99%), zinc nitrate hexahydrate (Zn(NO3)2·6H2O, 99%), ethylene glycol (C2H6O2, >99%), and AC were purchased from HWRK Chem. GEM and MOX were provided by Chengdu Sino-Strong Pharmaceutical Co. Ltd. The properties and molecular structures of the drugs are shown in Table 1.

Table 1

The property of GEM and MOX

DrugMolecular formulaMolecular structurepKa
GEM C18H20FN5O4·CH3SO3 6.02 ± 0.70 
MOX C21H24FN3O4·HCl  6.43 ± 0.50 
DrugMolecular formulaMolecular structurepKa
GEM C18H20FN5O4·CH3SO3 6.02 ± 0.70 
MOX C21H24FN3O4·HCl  6.43 ± 0.50 

Synthesis procedure

ZnFe2O4/AC magnetic composite was prepared using a microwave-assisted hydrothermal method. In a beaker, Fe(NO3)3·9H2O (8.08 g), Zn(NO3)2·6H2O (2.98 g), and ethylene glycol (80 mL) were added and mixed for 20 min. Then, NaOH (0.5 M) solution was used to adjust the pH to 11. A light green transparent gel was obtained. Then AC (2.17 g) was added and the suspension stirred vigorously for another 20 min. The black mixture was transferred into a reaction still and reacted in a solvothermal microwave reactor (XH-800S-10) at 453 K for 20 min. After being cooled down to room temperature, the collected solid was washed with deionized water and ethanol to remove the residual reactants. Finally, the solid was dried at 373 K for 24 h.

ZnFe2O4 was prepared according to the above method without addition of AC.

Characterization methods

The magnetism of the sample was characterized with a VSM-Versalab vibrating sample magnetometer. The Fourier transform infrared spectroscopy (FT-IR) spectroscopy data were recorded on a Nicolet iS50 FT-IR spectrometer. The phase composition of the sample was determined with a D8 Advance X diffractometer equipped with Cu Kα radiation (λ = 1.54178 Å). Nitrogen adsorption–desorption measurements at 77 K were performed on an AutosorbiQ-MP surface area analyzer. The zeta potentials data were obtained using a Zetasizer Nano ZS Zeta potential analyzer. The morphologies of the samples were determined with an FEI Inspect F50 field emission–scanning electron microscope (FE–SEM). The elemental analysis was carried on the SEM equipped with an energy dispersive X-ray (EDX) system.

Adsorption experiments

In this work, 0.01 g adsorbent was added to a 20-mL vial that contained 10 mL GEM or MOX aqueous solution. The resulting suspension was stirred for the desired time in a shaking table at 303 K and 155 rpm. The solid–liquid mixture was separated with a magnet, and the clear solution was measured for the concentration of the adsorbates using UV–Vis spectroscopy (TU-1901, Persee). The adsorption capacity was calculated by the following formula:
formula
(1)
where Qe (mg g−1) is the equilibrium adsorption amount of GEM or MOX of the sample; C0 (mg L−1) is the concentration of the solution concentration before adsorption; Ce (mg L−1) represents the concentration of the solution at adsorption equilibrium; V (L) is the volume of GEM or MOX solution; and m (g) is the mass of the adsorbent. All relevant adsorption experiments were repeated three times to ensure the accuracy of data.

Characterization of magnetic ZnFe2O4/AC composite

The crystal structure of the sample was characterized with X-ray powder diffraction (XRD) measurements. Figure 1(a) shows that the main characteristic diffraction peaks of the synthesized ZnFe2O4 can be found at 29.96, 35.20, 36.98, 42.46, 53.34, 56.97, and 62.13°, respectively, corresponding to the crystal plane positions of 220, 311, 222, 400, 422, 511, and 440 of ZnFe2O4 recorded in the standard JCPDS database (Sharma et al. 2017), demonstrating the successful synthesis of ZnFe2O4. Furthermore, similar peaks can be found in the XRD pattern of ZnFe2O4/AC, indicating the composite contains ZnFe2O4 phase. On the other hand, the characteristic diffraction peaks of AC were not found for its amorphous structure. To verify the existence of AC in the composite, as well as the component of the sample, SEM–energy dispersive X-ray spectroscopy (EDS) characterization was carried out as shown in Figure 1(b). It can be seen that the composite consisted of the elements of C, O, Fe, and Zn. The molar ratio of Zn and Fe was ∼1:2, which is consistent with the standard ratio of ZnFe2O4. In relation to the high content of C, we therefore suggest the synthesized composite was composed of ZnFe2O4 and AC.

Figure 1

(a) The XRD patterns of ZnFe2O4/AC, ZnFe2O4, and AC; (b) the EDS pattern and elemental content of ZnFe2O4/AC.

Figure 1

(a) The XRD patterns of ZnFe2O4/AC, ZnFe2O4, and AC; (b) the EDS pattern and elemental content of ZnFe2O4/AC.

Close modal

The morphology of ZnFe2O4/AC was characterized with SEM images. As shown in Figure 2, the composite consisted of the irregular micron-scale particles. ZnFe2O4 was dispersed on the surface of AC and the particle size ranged from 1 to 2 μm. Figure 3 shows the FT-IR spectra of ZnFe2O4, AC, and ZnFe2O4/AC. It can be seen that the signs in the spectrum of the synthesized ZnFe2O4/AC was almost consistent to those of AC because of the much higher content of AC in the composite, as demonstrated by the EDS data and SEM images. The peaks of ZnFe2O4/AC at 1,630 cm−1 and 600 cm−1 were attributed to C = O stretching (Chowdhury et al. 2012) and C–H bending vibrations (Sharma et al. 2017), respectively.

Figure 2

The SEM images of ZnFe2O4/AC: (a) full view; (b) partial enlarged image of the marked area in (a); (c) enlarged image of the marked area in (b).

Figure 2

The SEM images of ZnFe2O4/AC: (a) full view; (b) partial enlarged image of the marked area in (a); (c) enlarged image of the marked area in (b).

Close modal
Figure 3

The FT-IR spectra of ZnFe2O4/AC, ZnFe2O4, and AC.

Figure 3

The FT-IR spectra of ZnFe2O4/AC, ZnFe2O4, and AC.

Close modal

The porosity of the sample was verified by N2 adsorption–desorption isotherm measurements at 77 K, as shown in Figure 4(a). The Brunauer–Emmett–Teller (BET) specific surface areas of ZnFe2O4 and AC were calculated to be 256.1 m2 g−1 and 1,223.6 m2 g−1, respectively, and the BET value of ZnFe2O4/AC was 723.5 m2 g−1, which is between AC and ZnFe2O4. In addition, the pore diameter distribution of the sample was calculated using the Barrett–Joyner–Halenda (BJH) method (Figure 4(b)). It was found that ZnFe2O4/AC was a mesoporous material with a pore diameter of ∼4 nm.

Figure 4

(a) N2 adsorption–desorption isotherms at 77 K and (b) BJH pore size distribution of ZnFe2O4/AC, ZnFe2O4, and AC.

Figure 4

(a) N2 adsorption–desorption isotherms at 77 K and (b) BJH pore size distribution of ZnFe2O4/AC, ZnFe2O4, and AC.

Close modal

The magnetic property of the sample was also measured. As shown in Figure 5, the saturation magnetization of pure ZnFe2O4 was 50 emu g−1. After being combined with AC, the magnetism reached 15.0 emu g−1. From the inset of Figure 5, the composite in water can be easily controlled by an external magnetic field, indicating the convenient separation from liquid–solid systems.

Figure 5

The magnetic properties of ZnFe2O4/AC and ZnFe2O4 at 298 K.

Figure 5

The magnetic properties of ZnFe2O4/AC and ZnFe2O4 at 298 K.

Close modal

Adsorption isotherms

Based on the characterization results, the synthesized magnetic ZnFe2O4/AC exhibited large BET specific surface area, large pore diameters, and excellent magnetism, indicating the possible potential in liquid-phase adsorption. Herein, the composite was used for adsorbing GEM and MOX with large sizes (14.46 Å × 7.91 Å and 8.60 Å × 14.23 Å) (Chai et al. 2019). First, the adsorption isotherms were measured to evaluate the adsorption capacity of ZnFe2O4/AC. The adsorption amounts of ZnFe2O4/AC for GEM and MOX increased with the increasing concentration, as shown in Figure 6. The experimental results showed that when the initial concentration of the solution was 1,000 mg L−1, the adsorption capacity of ZnFe2O4/AC for GEM and MOX could reach up to 433.4 mg g−1 and 388.8 mg g−1, respectively.

Figure 6

Relationship between equilibrium adsorption amount and relative concentration of GEM and MOX (conditions: C0, 10–1,000 mg L−1; time, 24 h; natural pH).

Figure 6

Relationship between equilibrium adsorption amount and relative concentration of GEM and MOX (conditions: C0, 10–1,000 mg L−1; time, 24 h; natural pH).

Close modal

To evaluate the performance of ZnFe2O4/AC, some comparisons were made with other materials. It can be seen that ZnFe2O4/AC exhibited better adsorption performance for GEM and MOX than other materials (Chai et al. 2019), including UiO-66, MIL-125-NH2, MIL-53, MIL-101, and MOF-808. Although the capacities of the ZnFe2O4/AC are slightly lower than those of MIL-101-SO3H, the magnetism allows this composite to be easily separated from the adsorbent-solution system.

The adsorption behavior of ZnFe2O4/AC was analyzed according to the Langmuir model and Freundlich model (Zhao et al. 2018).

Langmuir isotherm model:
formula
(2)
Freundlich isotherm model:
formula
(3)
where Ce (mg L−1) is the equilibrium concentration of GEM or MOX, and KL and Qm are the Langmuir adsorption constant and the adsorption capacity at equilibrium, respectively, which can be obtained from the slope and intercept in the fitted line graph. KF and n are the Freundlich correlation parameters, which can be calculated from the slope and intercept of the equation in the line graph fitted by ln Qe to ln Ce. Figure 7 and Table 2 show the isotherm models fitting results of GEM and MOX adsorption in ZnFe2O4/AC. It can be seen that the adsorption behaviors of GEM and MOX are well fitted with the Freundlich isotherm model. In this work, the adsorption of GEM and MOX on ZnFe2O4/AC composite is favorable for 1/n < 1 (Tan et al. 2008).
Table 2

Parameters of the isotherm models

DrugLangmuir isotherm
Freundlich isotherm
Qm (mg g−1)KL (min−1)R2KF ((L mg−1)1/n mg g−1)1/n (g min−1 mg−1)R2
GEM 483.1 0.0114 0.9840 11.87 0.5528 0.9854 
MOX 429.2 0.0089 0.9376 11.83 0.6007 0.9720 
DrugLangmuir isotherm
Freundlich isotherm
Qm (mg g−1)KL (min−1)R2KF ((L mg−1)1/n mg g−1)1/n (g min−1 mg−1)R2
GEM 483.1 0.0114 0.9840 11.87 0.5528 0.9854 
MOX 429.2 0.0089 0.9376 11.83 0.6007 0.9720 
Figure 7

Isotherm model fitting curves: (a) Langmuir isotherm and (b) Freundlich isotherm.

Figure 7

Isotherm model fitting curves: (a) Langmuir isotherm and (b) Freundlich isotherm.

Close modal

Adsorption kinetics

Adsorption kinetics is an important factor to understand the adsorption reaction pathway (Gürses et al. 2014). As shown in Figure 8, fast adsorptions of GEM and MOX were found at only 5 min, and the adsorption capacities at this time can reach up to 70.2% and 67.9% of the saturated capacities, respectively. Adsorption equilibrium was achieved at ∼12 h for both GEM and MOX. The adsorption kinetics of GEM and MOX on ZnFe2O4/AC were further studied according to two classic kinetics models.

Figure 8

Effect of contact time on adsorption of GEM and MOX (conditions: C0, 1,000 mg L−1; natural pH = 4.5 for both GEM and MOX solutions).

Figure 8

Effect of contact time on adsorption of GEM and MOX (conditions: C0, 1,000 mg L−1; natural pH = 4.5 for both GEM and MOX solutions).

Close modal
Pseudo-first-order model (Zhao et al. 2019):
formula
(4)
Pseudo-second-order model (Zheng et al. 2019):
formula
(5)
where Qt (mg g−1) is the adsorption capacity at time t (min), and k1 (min−1) and k2 (g min−1 mg−1) are rate constants of pseudo-first-order model and pseudo-second-order model, respectively. From the fitting results in Figure 9 and Table 3, the correlation coefficients of GEM and MOX adsorbed on ZnFe2O4/AC from the pseudo-second-order model can both reach 0.9995, clearly larger than those from the pseudo-first-order model, indicating that the pseudo-second-order model can describe the adsorption behaviors better. Thus, we suggest the rate controlling step of the adsorption processes of GEM and MOX on ZnFe2O4/AC may be chemical adsorptions (Zheng et al. 2019).
Table 3

Parameters of the kinetics models

DrugQe,exp (mg g−1)Pseudo-first-order model
Pseudo-second-order model
Qe, cal (mg g−1)k1 (min−1)R2Qe, cal (mg g−1)k2 (g min−1 mg−1)R2
GEM 430.3 81.27 3.51 × 10−3 0.9505 429.2 2.83 × 10−4 0.9995 
MOX 386.1 94.32 4.18 × 10−3 0.9801 387.6 2.40 × 10−4 0.9995 
DrugQe,exp (mg g−1)Pseudo-first-order model
Pseudo-second-order model
Qe, cal (mg g−1)k1 (min−1)R2Qe, cal (mg g−1)k2 (g min−1 mg−1)R2
GEM 430.3 81.27 3.51 × 10−3 0.9505 429.2 2.83 × 10−4 0.9995 
MOX 386.1 94.32 4.18 × 10−3 0.9801 387.6 2.40 × 10−4 0.9995 
Figure 9

Kinetics models fitting curves: (a) pseudo-first-order model and (b) pseudo-second-order model.

Figure 9

Kinetics models fitting curves: (a) pseudo-first-order model and (b) pseudo-second-order model.

Close modal

Effect of pH

In general, solution pH has a large influence on ionic adsorbates upon electrostatic interaction. Thus, in this work, adsorption behaviors at pH 5–13 were studied systematically. The pH of the solution was adjusted using HCl (0.1 M) and NaOH (0.1 M) solutions. Figure 10(a) shows the adsorption capacities of GEM and MOX at pH 5–13. With the increase of solution pH from 5 to 13, the capacities first increased and then decreased gradually, and the optimal pH is 6–7.

Figure 10

(a) The effect of pH on GEM and MOX adsorption and (b) the zeta potential diagram of ZnFe2O4/AC (conditions: C0, 1,000 mg L−1; time, 24 h).

Figure 10

(a) The effect of pH on GEM and MOX adsorption and (b) the zeta potential diagram of ZnFe2O4/AC (conditions: C0, 1,000 mg L−1; time, 24 h).

Close modal

To understand this phenomenon, the charge property of ZnFe2O4/AC was analyzed using zeta potential measurement at pH 5–13. As shown in Figure 10(b), ZnFe2O4/AC was positively charged at pH < 5.8, and negatively charged at pH > 5.8. On the other hand, according to the pKa values of these drugs (Table 1), GEM and MOX existed as the anionic forms at pH < 6.02 and pH < 6.43, respectively. Thus, at pH 6.0, electrostatic interaction may exist between surface negatively charged ZnFe2O4/AC and cationic GEM and MOX molecules, and the interactions may be weak. At pH ≤ 5.0, the surface of ZnFe2O4/AC shifted to be positively charged and, accordingly, the electrostatic interaction disappeared, leading to the reduced capacities. Similarly, at pH ≥ 7.0, the interaction did not exist between the surface of the negatively charged adsorbent and anionic GEM and MOX molecules.

Effect of coexisting inorganic salts

Industrial wastewater commonly contains some coexisting inorganic ions, such as Na+, K+, Ca2+, Cl, , and . Thus, from the practical viewpoint, it is necessary to explore the effect of these coexisting substances on the adsorption process. In this work, the concentrations of the salts were consistent with that of GEM and MOX (500 mg L−1). From Figure 11, it can be seen that the coexisting substances, including monovalent and bivalent ions, have slightly negative effects on the adsorption of GEM and MOX. ZnFe2O4/AC may therefore have potential in the practical treatment of wastewater containing GEM and MOX.

Figure 11

Effect of coexisting inorganic salts on the (a) GEM and (b) MOX adsorption onto ZnFe2O4/AC (conditions: C0, 500 mg L−1; time, 24 h; natural pH 4.9 and 5.6 for GEM and MOX, respectively).

Figure 11

Effect of coexisting inorganic salts on the (a) GEM and (b) MOX adsorption onto ZnFe2O4/AC (conditions: C0, 500 mg L−1; time, 24 h; natural pH 4.9 and 5.6 for GEM and MOX, respectively).

Close modal

Adsorption mechanism investigation

ZnFe2O4 is commonly regarded as a photocatalyst (Li et al. 2011; Arimi et al. 2018; Liu et al. 2019). Therefore, to understand the removal mechanism of GEM and MOX, the effect of light on the adsorption was investigated, as shown in Figure 12(a) and 12(b). The concentration curves at visible light and dark environment almost overlapped completely, indicating photodegradation may not exist in the removal processes of GEM and MOX.

Figure 12

Effect of light on the (a) GEM and (b) MOX adsorption onto ZnFe2O4/AC.

Figure 12

Effect of light on the (a) GEM and (b) MOX adsorption onto ZnFe2O4/AC.

Close modal

Furthermore, as stated in the previous section, electrostatic attraction interaction existed in the adsorption process of GEM and MOX at pH 6.0. However, a high adsorption capacity (>300 mg g−1) was still obtained even with the electrostatic repulsion at pH ≤ 5.0 or pH ≥ 7.0. Thus, electrostatic interaction may not be the unique force for the adsorption of GEM and MOX on ZnFe2O4/AC. As shown in Table 1, GEM and MOX both contained some organic functional groups, such as –NH and –COOH, which can interact with C = O groups of AC via H-bond interaction. Previously, the adsorption of organic molecules with various groups over C-based materials has been explained by the formation of H-bond interaction (Baccar et al. 2012; Bhadra et al. 2016; Jauris et al. 2016). Therefore, we suggest that electrostatic interaction and H-bond interaction contributed to the adsorption of GEM and MOX on ZnFe2O4/AC.

ZnFe2O4/AC has been synthesized using the microwave method and studied for its adsorption performance toward GEM and MOX from aqueous solution. The largest adsorption capacity for GEM and MOX can reach 433.4 mg g−1 and 388.8 mg g−1, respectively. Adsorption data were well-fitted with the Freundlich isotherm and the pseudo-second-order model. The coexisting substances, including monovalent and bivalent ions, have slightly negative effects on the adsorption, and the ZnFe2O4/AC can be easily separated by its magnetism from water. The possible adsorption mechanism of GEM and MOX on ZnFe2O4/AC involves electrostatic interaction and H-bond interaction. Thus, this work may provide a guideline for improving GEM and MOX adsorption for future.

This work was supported by PhD Scientific Research Foundation of Taiyuan University of Science and Technology (No. 20182020) and Key Research Foundation of Science and Technology of Shanxi Province (No. 201803D121099).

The authors have no conflict of interests.

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

Arimi
A.
Megatif
L.
Granone
L. I.
Dillert
R.
Bahnemann
D. W.
2018
Visible-light photocatalytic activity of zinc ferrites
.
Journal of Photochemistry and Photobiology A: Chemistry
366
,
118
126
.
Baccar
R.
Sarrà
M.
Bouzid
J.
Feki
M.
Blánquez
P.
2012
Removal of pharmaceutical compounds by activated carbon prepared from agricultural by-product
.
Chemical Engineering Journal
211–212
,
310
317
.
Bhadra
B. N.
Seo
P. W.
Jhung
S. H.
2016
Adsorption of diclofenac sodium from water using oxidized activated carbon
.
Chemical Engineering Journal
301
,
27
34
.
Blondeau
J. M.
Tillotson
G.
2008
Role of gemifloxacin in the management of community-acquired lower respiratory tract infections
.
International Journal of Antimicrobial Agents
31
,
299
306
.
Chai
F.
Zhao
X.
Gao
H.
Zhao
Y.
Huang
H.
Gao
Z.
2019
Effective removal of antibacterial drugs from aqueous solutions using porous metal-organic frameworks
.
Journal of Inorganic and Organometallic Polymers and Materials
29
,
1305
1313
.
Chowdhury
Z. Z.
Zain
S. M.
Khan
R. A.
Islam
M. S.
2012
Preparation and characterizations of activated carbon from kenaf fiber for equilibrium adsorption studies of copper from wastewater
.
Korean Journal of Chemical Engineering
29
,
1187
1195
.
Fu
H.
Li
X.
Wang
J.
Lin
P.
Chen
C.
Zhang
X.
Suffet
I.
2017
Activated carbon adsorption of quinolone antibiotics in water: performance, mechanism, and modeling
.
Journal of Environmental Sciences
56
,
145
152
.
Hammama
M. A.
Wagdy
H. A.
Nashar
R. M.
2018
Moxifloxacin hydrochloride electrochemical detection based on newly designed molecularly imprinted polymer
.
Sensors and Actuators B: Chemical
275
,
127
136
.
Huber
M. M.
Korhonen
S.
Ternes
T. A.
Gunten
U.
2005
Oxidation of pharmaceuticals during water treatment with chlorine dioxide
.
Water Research
39
,
3607
3617
.
Jauris
I. M.
Matos
C. F.
Saucier
C.
Lima
E. C.
Zarbin
A. J. G.
Fagan
S. B.
Machado
F. M.
Zanella
I.
2016
Adsorption of sodium diclofenac on graphene: a combined experimental and theoretical study
.
Physical Chemistry Chemical Physics
18
,
1526
1536
.
Konicki
W.
Siber
D.
Narkiewicz
U.
2017
Removal of Rhodamine B from aqueous solution by ZnFe2O4 nanocomposite with magnetic separation performance
.
Journal of Chemical Technology
19
,
65
74
.
Kyzas
G. Z.
Kostoglou
M.
Lazaridis
N. K.
Lambropoulou
D. A.
Bikiaris
D. N.
2013
Environmental friendly technology for the removal of pharmaceutical contaminants from wastewaters using modified chitosan adsorbents
.
Chemical Engineering Journal
222
,
248
258
.
Snyder
S. A.
Adham
S.
Redding
A. M.
Cannon
F. S.
DeCarolis
J.
Oppenheimer
J.
Wert
E. C.
Yoon
Y.
2007
Role of membranes and activated carbon in the removal of endocrine disruptors and pharmaceuticals
.
Desalination
202
,
156
181
.
Yu
S.
Fujino
T.
Yoshimura
M.
2003
Hydrothermal synthesis of ZnFe2O4 ultrafine particles with high magnetization
.
Journal of Magnetism and Magnetic Materials
256
,
420
424
.
Zhang
X.
Guo
W.
Ngo
H. H.
Wen
H.
Li
N.
Wu
W.
2016
Performance evaluation of powdered activated carbon for removing 28 types of antibiotics from water
.
Journal of Environmental Management
172
,
193
200
.
Zhao
Y.
Li
W.
Liu
J. M.
Huang
K.
Wu
C.
Shao
H.
Chen
H.
Liu
X.
2017
Modification of garlic peel by nitric acid and its application as a novel adsorbent for solid-phase extraction of quinolone antibiotics
.
Chemical Engineering Journal
326
,
745
755
.
Zhao
X.
Wei
Y.
Zhao
H.
Gao
Z.
Zhang
Y.
Zhi
L.
Wang
Y.
Huang
H.
2018
Functionalized metal-organic frameworks for effective removal of Rocephin in aqueous solutions
.
Journal of Colloid and Interface Science
514
,
234
239
.
Zhao
X.
Zhao
Y.
Zheng
M.
Liu
S.
Xue
W.
Du
G.
Wang
T.
Gao
X.
Wang
K.
Hu
J.
Gao
Z.
Huang
H.
2019
Efficient separation of vitamins mixture in aqueous solution using a stable zirconium-based metal-organic framework
.
Journal of Colloid and Interface Science
555
,
714
721
.
Zheng
M.
Zhao
X.
Wang
K.
She
Y.
Gao
Z.
2019
Highly efficient removal of Cr(VI) on a stable metal–organic framework based on enhanced H-bond interaction
.
Industrial and Engineering Chemistry Research
58
,
23330
23337
.
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