Highly Effective Removal of Pharmaceutical Compounds from

Subscriber access provided by WEBSTER UNIV

General Research

Highly effective removal of pharmaceutical compounds from aqueous solution by magnetic Zr-based MOFs composites Ruiqi Zhang, Zhen Wang, Zixin Zhou, Di Li, Tiefeng Wang, Ping Su, and Yi Yang Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.8b05244 • Publication Date (Web): 20 Feb 2019 Downloaded from http://pubs.acs.org on February 21, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Industrial & Engineering Chemistry Research

199x129mm (300 x 300 DPI)

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Highly effective removal of pharmaceutical compounds from aqueous solution by magnetic Zr-based MOFs composites

Ruiqi Zhang, Zhen Wang, Zixin Zhou, Di Li, Tiefeng Wang, Ping Su*, and Yi Yang*

Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, College of Science, Beijing University of Chemical Technology, Beijing 100029, China

*Corresponding author: E-mail: [email protected] [email protected]


Page 2 of 29

Page 3 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Abstract In this research, the magnetic UiO-66-NH2 composites were prepared and applied as adsorbents for the effective removal of salicylic acid (SA) and acetylsalicylic acid (ASA) from aqueous media. The as-prepared adsorbent inherits both the excellent properties of metal organic frameworks and the magnetic separation property of magnetic material, which makes the magnetic UiO-66-NH2 composite exhibits a rapid separation rate and high capacity. The adsorption kinetics were well fitted with the pseudo-second-order model, and the adsorption isotherm could be well explained using the Langmuir isotherm. The dominant mechanism for adsorption of SA and ASA was hydrogen-bonding, the affinity of carboxyl groups with Zr-O clusters and electrostatic interactions. The high adsorption capacities, easy separation process, fast adsorption kinetics, and satisfactory reusability of the magnetic UiO-66-NH2 give it fantastic potential as adsorbents for adsorptive separation of pharmaceutical contaminants from aqueous media. Keywords: adsorption, pharmaceutical removal, magnetic, UiO-66-NH2 1. Introduction The global production and consumption of pharmaceuticals have increased notably over the last few years.1-2 The leakage and discharge of these pharmaceuticals into the natural environments without treatment presents a risk of poisoning to aquatic organisms and can have negative effects on human health.3-4 Salicylic acid (SA) is widely used in organic synthesis, while acetylsalicylic acid (ASA) is the most common non-steroidal anti-inflammatory drug. SA and ASA (chemical structures are



shown in Figure S1) are discharged into the environment not only directly via wastewater, but also indirectly as metabolite products of other chemicals. The concentrations of SA and ASA that have been measured in effluent waste-water have been recorded up to the μg mL−1 level.5-6 Ingestion of SA and ASA can lead to a headache and nausea, and interferes in functioning naturally of the liver and kidneys in humans. Therefore, removing these pharmaceuticals from water is a necessary challenge, and one that requires the development of alternative approaches. Among the many approaches7-11 explored for removing pharmaceutical contaminants from water, adsorption technology has been identified as especially effective as well as being economical because of its efficient target uptake, high removal rate and ease of operation. To date, a wide range of adsorptive materials for removal of pharmaceuticals have been studied, including silica-based materials,12 resins,13-14 metal oxides,

15-16

activated carbon,17-18 and graphene oxide.19 Recently,

metal-organic frameworks (MOFs) have gained particular concern as adsorbents with great promise in liquid-phase adsorption.20-29 MOFs, as an advanced class of porous crystalline materials, possess fascinating structures and properties, such as abundant aromatic organic ligands and Lewis acid sites, high surface area, surface functionalization and various structures and topologies. The UiO (University of Oslo) framework is a representative series of Zr-based MOFs. Thereinto, UiO-66 MOFs possess octahedral and tetrahedral cavities, 11 Å and 8 Å in free diameters, respectively.30-31 This framework is relatively resistant to attack by H2O and acidic or basic reactants. The exceptional chemical, thermal and


Page 4 of 29

Page 5 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


aqueous stability of UiO-66 provides a theoretical motivation for applying UiO-66 for water treatment. Furthermore, composites of magnetic materials and MOFs inherit both the excellent properties of MOFs and the magnetic separation properties of magnetic materials, and can therefore simplify the adsorption process, avoiding tedious centrifugation or filtration separation.32-34 Herein, we report the adsorption of the pharmaceuticals SA and ASA from water media using Zr-based MOFs of UiO-66-NH2. The prepared adsorbent was fully characterized and the adsorption behavior of SA and ASA removal was systematically evaluated, in which it was demonstrated that the adsorption performance was well fitted with pseudo-second-order kinetics and the Langmuir model. As a result of combining the properties of magnetic particles with those of MOFs, the magnetic UiO-66-NH2 composite exhibits a rapid separation rate and high adsorption capacity. All of these findings endorse the magnetic UiO-66-NH2 as an adsorbent with great potential for the adsorptive separation of SA and ASA from environmental water in practical future applications. 2. Material and methods 2.1. Chemicals Salicylic acid was purchased from Aladdin (Shanghai, China). Acetylsalicylic acid was obtained from Sigma-Aldrich (Shanghai, China). HPLC-grade methanol, 2-aminoterephthalic acid, ZrCl4 and tetraethyl orthosilicate (TEOS) were supplied by J&K Scientific (Beijing, China). FeCl3·6H2O, anhydrous sodium acetate and the other chemicals used in the current research were supplied by Beijing Chemical Reagent



Co., Ltd. (Beijing, China). 2.2 Synthesis of magnetic UiO-66-NH2 The process to prepare the magnetic UiO-66-NH2 composite is illustrated in Figure 1A. The Fe3O4 magnetic particles were prepared by a typical solvothermal reduction method. Subsequently, core-shell structured Fe3O4@SiO2 magnetic particles (MNPs) were synthesized by TEOS coated on the Fe3O4 particles. The preparation of magnetic UiO-66-NH2 followed a previously published procedure with small modification.35 In brief, 30 mL dimethylformamide (DMF) was added to dissolve MNPs (0.2 g) and ZrCl4 (0.466 g, 2.0 mmol) followed by ultrasonic mixing for 30 min; then 30 mL DMF was added to dissolve 2-aminoterephthalic acid (0.362 g, 2.0 mmol) separately; the both two solutions were mixed in a 250 mL flask by ultrasonic method for 5 min and the flask was heated at 120 °C under mechanical stirring for 6h. The obtained MNPs@UiO-66-NH2 material was washed with DMF and ethanol three times and finally dried at 60 °C in vacuum.


Page 6 of 29

Page 7 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 1. Schematics of (A) the synthesis of MNPs@UiO-66-NH2 (B) the adsorption procedure. 2.3 Characterization To characterize the morphologies and dimensions of the magnetic UiO-66-NH2, the characterization images of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were investigated on the Zeiss Supera55 and on Philips Model Tecnai 20, respectively. X-ray powder diffraction (XRD, Ultima 3 diffractometer, Rigaku ) using Ni-filtered Cu Kα radiation was employed to investigate the crystal structure of the magnetic UiO-66-NH2. Fourier transform infrared (FTIR) were conducted with a Nicolet spectrometer (Thermo Fisher Scientific) with KBr pellets. A 1100SF Mettler Toledo thermal analyzer (Columbus) was used under nitrogen for thermodynamic analysis (TGA) measurements. The surface area and pore volume of the magnetic composites were gotten by the Brunauer-Emmett-Teller (BET) using an ASAP 2010 micropore physisorption



analyzer. The magnetic properties of the prepared magnetic composites were investigated with a 7404 vibrating sample magnetometer (VSM, Lake Shore). The UV–vis absorbance spectra were measured by a TU-1950 spectrophotometer (Beijing Purkinje). 2.4 Magnetic adsorption procedure Figure. 1B shows the schematic chart of the magnetic adsorption procedure. To study the influence of pH on the SA and ASA removal of the magnetic UiO-66-NH2, 0.1 M HCl and 0.1 M NaOH with insignificant volumes were employed for regulating the initial pH values of the adsorption procedure in the pH scale from 2 to10. To study the adsorption kinetics, 20 mg of the adsorbent was introduced to 20 mL of 100 mg L−1 SA and ASA solutions adjusted to pH 6. The solutions were then shaken at ambient temperature at predetermined time intervals (0.5–120 min). To measure the adsorption isotherms, 20 mg of the material was added to 20 mL of 100 mg L−1 SA and ASA solutions adjusted to pH 6. The solutions were then shaken at the temperatures of 10, 30 and 50 °C (10 min for SA and 60 min for ASA). Subsequently, an Nd-Fe-B strong magnet was put beside the tube bottle to separate the magnetic adsorbents. The concentrations of SA and ASA in the initial solution and the residual solution after adsorption were measured with ultraviolet–visible (UV–vis) spectrometer according to the maximum wavelength at 297 nm and 275 nm. All the adsorption experiments were performed in triplicate. The amount of adsorbates removed per unit mass of the adsorbent (Qe) was evaluated by the equation as below:


Page 8 of 29

Page 9 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


where Co stands for the original analyte concentration; Ce presents the analyte concentration at equilibrium (mg mL−1), V is the volume of the adsorbates solution (mL) and M is the total mass of the sorbent added (g). 2.5 Regeneration procedure The spent magnetic UiO-66-NH2 was recycled by stirring with 0.1 M HCl in methanol for 10 h, then washing twice with methanol and drying at 60 °C under vacuum overnight. Twenty milligrams of adsorbent and 20 mL SA and ASA (100 g mL−1) solutions at pH 6 were used. The regeneration of magnetic UiO-66-NH2 was recycled three times according to the above regeneration procedure before adsorption process each time. 3. Results and discussion 3.1 Characterization of the magnetic UiO-66-NH2 The silica layer stabilizes the Fe3O4 core, and the chelation of Zr4+ by the -OH groups in the silica layer drives the growth of Zr-MOFs on the surface of Fe3O4.29 The surface morphologies and dimensions of the as-synthesized magnetic Zr-MOFs composites were characterized using SEM and TEM. Figure 2a demonstrated that the as-synthesized magnetic particles were spherical-shaped and monodisperse with an average diameter of 490 nm. After silanization with TEOS, the MNPs particles (Figure 2b) had relatively smooth surfaces and the mean size was larger compared with the raw Fe3O4. Figure 2c shows the pronounced change in morphology that



Page 10 of 29

occurred because of the monolayer modification of UiO-66-NH2. The strong Zr and Fe element signals from the EDX elemental mapping (Figure 2d) also indicated that Zr-MOF was successfully coated onto the magnetic particles. The TEM images (Figure S2) also indicated the core-shell architecture composed of MNPs cores and UiO-66-NH2 shells.

Figure 2. SEM images of (a) Fe3O4, (b) MNPs, (c) MNPs@UiO-66-NH2 (d) EDX elemental mapping of Fe, Zr, and Si of MNPs@UiO-66-NH2 composites. Figure 3a shows the XRD patterns of MNPs and MNPs@UiO-66-NH2. All of the reflection peaks are matched well with those of crystalline Fe3O4 or UiO-66-NH2,36 implying that the MNPs was successfully coated by the Zr-MOFs. The calculated BET surface areas of MNPs and MNPs@UiO-66-NH2 (Figure 3b) are 59.7 and 615.6 m2

g−1,

respectively.

The

BET

surface

area


of

the

as-synthesized

Page 11 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


MNPs@UiO-66-NH2 is larger than that of MNPs, which further implied that the formation of the UiO-66-NH2 shell with micropores. The FTIR spectra of Fe3O4, MNPs, UiO-66-NH2 and MNPs@UiO-66-NH2 are presented in Figure 3c. The characteristic band at 574 cm − 1 in all the spectra could be determined for the Fe–O–Fe vibration. The typical absorption bands at 1092 cm−1 and 479cm-1 belonged to the Si–O–Si stretching vibrations. The absorption peak of the C=O bonds (1652 cm−1) and of the benzene skeleton vibration (1500 cm−1 and 1615 cm−1) are clearly observed. Peaks at 1560 and 1410 cm − 1 were due to the symmetric and asymmetric stretching vibration of carboxylate, respectively. The absorbance at 1258 cm-1 was assigned to the stretching vibration of C-N. Additionally, the absorbance at 765 cm-1 was assigned to the benzene ring substitution of 2-aminoterephthalic acid. The TGA curves of the synthesized magnetic adsorbents are shown in Figure 3d. The measured weight of Fe3O4@SiO2 remained almost unchanged across the entire temperature range. For the synthesized MNPs@UiO-66-NH2 composite, the elimination of water or solvent led to a slight weight loss below 100 °C, while the mass loss over the temperature range of 100 °C to 570 °C could be corresponded to the dehydroxylation of zirconium oxo clusters and degradation of organic ligands. The significant weight loss of MNPs @UiO-66-NH2 as the temperature changed from 100 °C to 800 °C further indicated the successful modification of MNPs with UiO-66-NH2. Figure. 3e shows the magnetic hysteresis loops of MNPs and MNPs@UiO-66-NH2. The magnetic saturation intensities of MNPs and MNPs@UiO-66-NH2 were 50.5 and 25.4 emu/g, respectively. The as-prepared magnetic materials remained an adequate



magnetic response to satisfy the need for magnetic separation. The XPS spectra (Figure. 3f) gave the chemical composition information of MNPs@UiO-66-NH2. The C 1 s (285.0 eV), Zr 3d (185.2 eV), Si 2p (104.1), and O 1s (532.5 eV) peaks could be found in the spectrum. Additional, FTIR and XPS were evaluated to obtain the chemical composition information of the magnetic adsorbents before and after targets adsorption. In Figure S3 and Figure S4, new characteristic peaks at 1690 and 1714 cm-1, belonged to the acetyl groups of ASA, indicate that ASA is adsorbed on the surface of the adsorbents. The O1s spectra of the magnetic adsorbent after SA and ASA adsorption are shown in Figure S4. Some peaks including O-C=O (533.9 eV), C-O (533.0 eV), Si-O (532.3 eV), C=O (531.5 eV) and Zr-O-Zr (530.4 eV) 24, 37appear in the spectra. The C-O (533.0 eV) and O-C=O (533.9 eV) peak intensities exhibit a relative increase after adsorption, probably due to a large amount of SA and ASA, which possess abundant carbon-oxygen bonds, being adsorbed onto the magnetic UiO-66-NH2.


Page 12 of 29

Page 13 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 3. (a) XRD patterns, (b) Nitrogen adsorption-desorption isotherms, (c) FTIR spectra, (d) TGA profile, (e) Magnetization curves and (f) XPS spectra of MNPs@UiO-66-NH2 composite. 3.2 Adsorption evaluation To optimize the adsorptive capability of MNPs@UiO-66-NH2, the influences of the reaction temperature and reaction time were studied. Crystallization reactions were carried out from 110 to 140 °C to observe the effect of temperature, and from 2 to 10



h to observe the effect of time (at the optimized temperature). As demonstrated in Figure 4, the adsorptive capability of magnetic UiO-66-NH2 varied considerably as a function of both crystallization temperature and time. The optimum temperature and time for the synthesis of magnetic UiO-66-NH2 were found to be 120 °C and 6 h, respectively.

Figure 4. Effect of UiO-66-NH2 crystallization temperature and time on the uptake of (a) (b) ASA and (c) (d) SA by the magnetic UiO-66-NH2 (UV absorption spectra of supernatant solutions after adsorption). 3.3 Effect of pH and mechanism of adsorption The solution pH is a significant factor that influences the adsorption capacity, as it can alter the electrostatic interactions between adsorbents and adsorbates. The adsorption performance of SA and ASA on the magnetic adsorbents were evaluated in


Page 14 of 29

Page 15 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


the pH scale from 2-10, and the obtained results are shown in Figure 5. Zeta potential of the magnetic UiO-66-NH2 on the basis of pH are shown in Figure S5. During adsorption at pH 2, ASA (pKa = 3.50) exists mainly in the neutral conjugated acid (R-COOH) form, hydrogen bonding and the affinity of the carboxyl groups with the Zr-O clusters dominates the adsorption of ASA on the surface of magnetic UiO-66-NH2. When the pH increases to 3.5 and above, the carboxyl groups of ASA become negatively charged and the surfaces of the magnetic UiO-66-NH2 become positively charged (-NH3+). This promotes favorable electrostatic interactions between ASA anions and the positively charged surfaces of the adsorbent. When the pH reaches 10, both ASA and the surface of the adsorbent become electronegative, which hinders the adsorption of ASA. The adsorption mechanism of SA (pKa = 2.98) is similar to ASA. Notably, however, the presence of an intramolecular hydrogen bond in the SA molecule may result in a much smaller change in the adsorption capacity (79.22–86.58 mg g−1) in the pH scale from 2 to 8. In summary, hydrogen bonds formed between the target molecules and the carboxyl acid or amino functional groups on the magnetic UiO-66-NH2 surface, and the affinity of the carboxyl groups with Zr-O clusters have significant functions in the adsorption process. Under various pH conditions, the electrostatic interactions can either promote or suppress the adsorption of SA and ASA on the adsorbents.



Figure 5. Effect of pH on the uptake of (a) ASA and (b) SA by the magnetic UiO-66-NH2 at 30 °C; SA and ASA concentration = 100 g mL−1, total volume = 20 mL, mass of adsorbent used = 20 mg. 3.4 Adsorption kinetics As shown in Figure 6, the contact time as a significant factor for the adsorption of SA and ASA was evaluated to illustrate the kinetic data of the adsorption performance. Experimentally, SA and ASA reached adsorption equilibrium (Qe) in roughly 10 and 60 min, respectively, suggesting that the MNPs@UiO-66-NH2 exhibited fast adsorption dynamics for the adsorptive separation of the targets from aqueous solution, especially SA. Both the pseudo-first-order and pseudo-second-order models were used to fit the adsorption kinetic parameters (Table 1). The results suggested that the pseudo-second-order equation are more accurate to describe the adsorption kinetics of both SA and ASA on MNPs@UiO-66-NH2, as it yielded higher correlation coefficients (R2 > 0.99). The values of Qe calculated from the pseudo-second-order equation were very close to the experimentally obtained values, which also verified that the adsorption behavior could be accurately described by pseudo-second-order


Page 16 of 29

Page 17 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


model. The expression of pseudo-second-order model is shown in Supporting information.

Figure 6. Effect of contact time on (a) SA and (c) ASA adsorption on magnetic adsorbent; pseudo-second-order kinetics of (b) SA and (d) ASA adsorption on magnetic adsorbent.

Table 1. Kinetic model parameters for SA and ASA adsorption on the magnetic UiO-66-NH2 Pseudo-first-order constants

Pseudo-second-order constants

k1 (min-1)

Qe (mg g-1)

R2

k2 (min-1)

Qe (mg g-1)

R2

SA

3.94

84.32

0.98402

6.49×10-2

87.57

0.99995

ASA

0.195

81.77

0.84893

2.83×10-3

90.74

0.99912

3.5 Adsorption isotherms



To understand in more detail the adsorption behavior of SA and ASA on the as-synthesized MNPs@UiO-66-NH2, the experimental parameters were applied to fit to the conventional Langmuir and Freundlich adsorption isotherm models (Figure 7). The equations are expressed as follows: Langmuir equation:

Freundlich equation:

where Qe and Qm (mg g−1) are the adsorptive capacity at equilibrium and the maximum mono-layer adsorptive capacity at equilibrium concentration, respectively. Ce (mg mL−1) is the adsorbate concentration at equilibrium. KL (mL mg−1) is the Langmuir constant corresponding to the intermolecular forces. KF (mL mg−1) and n are the Freundlich equation constants. The parameters of the models are presented in Table 2. For SA and ASA, the experimental data gives better fit with the Langmuir isotherm model, which yields a higher R2 compared with the Freundlich isotherm model, implying that adsorption follows a monolayer molecular adsorption and the intermolecular forces decrease as the distance increased with the adsorption surface. The adsorption capacity of SA decreases as the temperature increases, which illustrates that the adsorption process is an exothermic process. In contrast to SA, the adsorption of ASA is slightly endothermic. Table 3 compares the adsorptive capacities of SA and ASA on the magnetic


Page 18 of 29

Page 19 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


UiO-66-NH2 and on other adsorbents from the literature. The magnetic UiO-66-NH2 shows exceptionally rapid uptake rates, and equal or even better adsorption ability than the other adsorbents. Moreover, the capability of magnetic removal instead of filtration makes the use of the magnetic UiO-66-NH2 especially attractive.

Figure 7. Langmuir adsorption isotherms on magnetic UiO-66-NH2 for (a) SA and (b) ASA at 10, 30 and 50 °C.

Table 2. Thermodynamic parameters of Langmuir and Freundlich model for SA and ASA adsorption on magnetic UiO-66-NH2

Langmuir model

Freundlich model

T (℃)

SA

ASA

Qm (mg/g)

KL

R2

KF (mg/g)

1/n

R2

10

140.45

0.108

0.99501

53.69

0.172

0.97263

30

128.70

0.121

0.99590

57.10

0.144

0.97035

50

106.496

0.334

0.99869

54.333

0.127

0.93213

10

98.62

0.106

0.99894

41.177

0.153

0.98546



Page 20 of 29

30

108.34

0.162

0.99891

49.682

0.142

0.93707

50

137.93

0.080

0.99514

45.093

0.198

0.95557

Table 3. Comparison of adsorption of various pharmaceuticals with previously published adsorbents Experimental conditions Target Adsorbent

Qe

Co

s

Time

Temp

(min)

. (°C)

Ref.

pH

ASA

(mg/g)

(mg/L)

9.92

2

6

0.67

25

38

6.19

500

6

24

25

39

Molecular imprinted polymer

~4.50

100

3

1.5

40

40

magnetic UiO-66-NH2

85.19

100

6

1

30

This work

5.62

100

-

3

25

41

Polar nano-dendritic adsorbent

43.0

50

3.5

0.25

25

42

Resins GQ-11

~275

600.7

-

8

25

43

magnetic UiO-66-NH2

86.65

100

6

0.17

30

This work

Chitosan/waste coffee-grounds composite Oxide-mesoporous silica MCM-41

SA

Cellulose acetate imprinted membrane assisted with chitosan-wrapped MWCNT

3.6 Regeneration and recycling In practical adsorption applications, the regeneration capacity of the used adsorbent is a pivotal issue. After regeneration, the used adsorbent was regenerated for the adsorption of target contamination. The saturation magnetization values of the


Page 21 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


adsorbent before and after recycling were 25.4 and 25.0 emu/g, respectively, and the magnetism of the adsorbent was almost undiminished. Figure 8 shows the adsorption amounts of the targets for three rounds of recycling. The adsorption ability of the magnetic UiO-66-NH2 for SA and ASA did not significantly decrease after recycling three times (adsorption capacity remained at 77% for SA and 70% for ASA), which indicates that the prepared magnetic UiO-66-NH2 can be regenerated and is suitable for practical application in future.

Figure 8. Recycling of magnetic UiO-66-NH2 for SA and ASA adsorption.

4. Conclusion In summary, the magnetic UiO-66-NH2 composite was successfully synthesized and applied as adsorbents for the efficient adsorptive separation of SA and ASA from aqueous media. The magnetic UiO-66-NH2 displayed excellent adsorption



performances for SA and ASA, and pseudo-second-order kinetics and Langmuir isotherm model could be employed to well describe the adsorption process. The affinity of Zr-O clusters with carboxyl groups, hydrogen bond and electrostatic interactions were regarded as the dominant adsorption mechanism. The high removal rate, exceptional adsorption capacity, satisfactory regenerability and easy magnetic separation process reveal the great possibility of the magnetic UiO-66-NH2 as adsorbents for the efficient removal of SA and ASA for the practical application.

Supporting Information: The expression of pseudo-second-order model. Structures of salicylic acid and acetylsalicylic acid. TEM images of Fe3O4@SiO2@UiO-66-NH2. FTIR spectra of the magnetic UiO-66-NH2 before and after adsorption of SA and ASA. The O1s XPS spectra of the magnetic UiO-66-NH2 before and after adsorption of SA and ASA. The zeta potential of the magnetic UiO-66-NH2 as a function of pH. Pseudo-first-order kinetics of SA and adsorption on magnetic UiO-66-NH2. Pseudo-first-order kinetics of ASA and adsorption on magnetic UiO-66-NH2.

Author information Corresponding Author * E-mail: [email protected]. * E-mail: [email protected]. Tel.: +86 10 64441521. Notes


Page 22 of 29

Page 23 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


The authors declare no competing financial interest.

Acknowledgments This work was supported by National Natural Science Foundation of China (Grant No. 21675008).

References (1) Van Boeckel, T. P.; Gandra, S.; Ashok, A.; Caudron, Q.; Grenfell, B. T.; Levin, S. A.; Laxminarayan, R., Global antibiotic consumption 2000 to 2010: an analysis of national pharmaceutical sales data. The Lancet Infect Dis 2014, 14, 742. (2) Yin, L.; Wang, B.; Yuan, H.; Deng, S.; Huang, J.; Wang, Y.; Yu, G., Pay special attention to the transformation products of PPCPs in environment. Emerging Contaminants 2017, 3, 69. (3) Yang, Y.; Ok, Y. S.; Kim, K. H.; Kwon, E. E.; Tsang, Y. F., Occurrences and removal of pharmaceuticals and personal care products (PPCPs) in drinking water and water/sewage treatment plants: A review. Sci Total Environ 2017, 596-597, 303. (4) Zepon Tarpani, R. R.; Azapagic, A., Life cycle environmental impacts of advanced wastewater treatment techniques for removal of pharmaceuticals and personal care products (PPCPs). J Environ Manage 2018, 215, 258. (5) Essandoh, M.; Kunwar, B.; Pittman, C. U.; Mohan, D.; Mlsna, T., Sorptive removal of salicylic acid and ibuprofen from aqueous solutions using pine wood fast pyrolysis biochar. Chem Eng J 2015, 265, 219.



(6) Rakic, V.; Rac, V.; Krmar, M.; Otman, O.; Auroux, A., The adsorption of pharmaceutically active compounds from aqueous solutions onto activated carbons. J Hazard Mater 2015, 282, 141. (7) Gadipelly, C.; Pérez-González, A.; Yadav, G. D.; Ortiz, I.; Ibáñez, R.; Rathod, V. K.; Marathe, K. V., Pharmaceutical Industry Wastewater: Review of the Technologies for Water Treatment and Reuse. Ind Eng Chem Res 2014, 53, 11571. (8) Xu, Y.; Liu, T.; Zhang, Y.; Ge, F.; Steel, R. M.; Sun, L., Advances in technologies for pharmaceuticals and personal care products removal. J Mater Chem A 2017, 5, 12001. (9) Rosman, N.; Salleh, W. N. W.; Mohamed, M. A.; Jaafar, J.; Ismail, A. F.; Harun, Z., Hybrid membrane filtration-advanced oxidation processes for removal of pharmaceutical residue. J Colloid Interf Sci 2018, 532, 236. (10) Lhotský, O.; Krákorová, E.; Mašín, P.; Žebrák, R.; Linhartová, L.; Křesinová, Z.; Kašlík, J.; Steinová, J.; Rødsand, T.; Filipová, A.; Petrů, K.; Kroupová, K.; Cajthaml, T., Pharmaceuticals, benzene, toluene and chlorobenzene removal from contaminated groundwater by combined UV/H2O2 photo-oxidation and aeration. Water Res 2017, 120, 245. (11) Park, J.; Yamashita, N.; Park, C.; Shimono, T.; Takeuchi, D. M.; Tanaka, H., Removal characteristics of pharmaceuticals and personal care products: Comparison between membrane bioreactor and various biological treatment processes. Chemosphere 2017, 179, 347. (12) Delle Piane, M.; Vaccari, S.; Corno, M.; Ugliengo, P., Silica-based materials as


Page 24 of 29

Page 25 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


drug adsorbents: first principle investigation on the role of water microsolvation on Ibuprofen adsorption. J Phys Chem A 2014, 118, 5801. (13) Jin, J.; Feng, T.; Gao, R.; Ma, Y.; Wang, W.; Zhou, Q.; Li, A., Ultrahigh selective adsorption of zwitterionic PPCPs both in the absence and presence of humic acid: Performance and mechanism. J Hazard Mater 2018, 348, 117. (14) Jin, J.; Feng, T.; Ma, Y.; Wang, W.; Wang, Y.; Zhou, Q.; Li, A., Novel magnetic carboxyl modified hypercrosslinked resins for effective removal of typical PPCPs. Chemosphere 2017, 185, 563. (15) Zhang, Y.; Zhu, H.; Szewzyk, U.; Lübbecke, S.; Uwe Geissen, S., Removal of emerging organic contaminants with a pilot-scale biofilter packed with natural manganese oxides. Chem Eng J 2017, 317, 454. (16) Liu, W.; Langenhoff, A. A. M.; Sutton, N. B.; Rijnaarts, H. H. M., Biological regeneration of manganese (IV) and iron (III) for anaerobic metal oxide-mediated removal of pharmaceuticals from water. Chemosphere 2018, 208, 122. (17) Tian, W.; Zhang, H.; Duan, X.; Sun, H.; Tade, M. O.; Ang, H. M.; Wang, S., Nitrogen- and Sulfur-Codoped Hierarchically Porous Carbon for Adsorptive and Oxidative Removal of Pharmaceutical Contaminants. ACS Appl Mater Inter 2016, 8, 7184. (18) Song, J. Y.; Bhadra, B. N.; Jhung, S. H., Contribution of H-bond in adsorptive removal of pharmaceutical and personal care products from water using oxidized activated carbon. Micropor Mesopor Mat 2017, 243, 221. (19) Zambianchi, M.; Durso, M.; Liscio, A.; Treossi, E.; Bettini, C.; Capobianco, M.



L.; Aluigi, A.; Kovtun, A.; Ruani, G.; Corticelli, F.; Brucale, M.; Palermo, V.; Navacchia, M. L.; Melucci, M., Graphene oxide doped polysulfone membrane adsorbers for the removal of organic contaminants from water. Chem Eng J 2017, 326, 130. (20) Zeng, Z.; Lyu, J.; Bai, P.; Guo, X., Adsorptive Separation of Fructose and Glucose by Metal–Organic Frameworks: Equilibrium, Kinetic, Thermodynamic, and Adsorption Mechanism Studies. Ind Eng Chem Res 2018, 57, 9200. (21) Akpinar, I.; Yazaydin, A. O., Rapid and Efficient Removal of Carbamazepine from Water by UiO-67. Ind Eng Chem Res 2017, 56, 15122. (22) Wang, Q.; Wang, X.; Shi, C., LDH Nanoflower Lantern Derived from ZIF-67 and Its Application for Adsorptive Removal of Organics from Water. Ind Eng Chem Res 2018, 57, 12478. (23) Lin, S.; Zhao, Y.; Yun, Y. S., Highly Effective Removal of Nonsteroidal Anti-inflammatory Pharmaceuticals from Water by Zr(IV)-Based Metal-Organic Framework: Adsorption Performance and Mechanisms. ACS Appl Mater Inter 2018, 10, 28076. (24) Yang, Q.; Wang, Y.; Wang, J.; Liu, F.; Hu, N.; Pei, H.; Yang, W.; Li, Z.; Suo, Y.; Wang, J., High effective adsorption/removal of illegal food dyes from contaminated aqueous solution by Zr-MOFs (UiO-67). Food Chem 2018, 254, 241. (25) Peng, Y.; Zhang, Y.; Huang, H.; Zhong, C., Flexibility induced high-performance MOF-based adsorbent for nitroimidazole antibiotics capture. Chem Eng J 2018, 333, 678.


Page 26 of 29

Page 27 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(26) Zhao, X.; Wei, Y.; Zhao, H.; Gao, Z.; Zhang, Y.; Zhi, L.; Wang, Y.; Huang, H., Functionalized metal-organic frameworks for effective removal of rocephin in aqueous solutions. J Colloid Interf Sci 2018, 514, 234. (27) Seo, P. W.; Khan, N. A.; Jhung, S. H., Removal of nitroimidazole antibiotics from water by adsorption over metal–organic frameworks modified with urea or melamine. Chem Eng J 2017, 315, 92. (28) Zhao, X.; Wang, K.; Gao, Z.; Gao, H.; Xie, Z.; Du, X.; Huang, H., Reversing the dye adsorption and separation performance of metal–organic frameworks via introduction of −SO3H groups. Ind Eng Chem Res 2017, 56, 4496. (29) Zhu, X.; Li, B.; Yang, J.; Li, Y.; Zhao, W.; Shi, J.; and Gu, J., Effective adsorption and enhanced removal of organophosphorus pesticides from aqueous solution by Zr-Based MOFs of UiO-67. ACS Appl Mater Inter 2015, 7, 223. (30) Katz, M. J.; Brown, Z. J.; Colon, Y. J.; Siu, P. W.; Scheidt, K. A.; Snurr, R. Q.; Hupp, J. T.; Farha, O. K., A facile synthesis of UiO-66, UiO-67 and their derivatives. Chem Commun 2013, 49, 9449. (31) Wu, C.; Zhu, X.; Wang, Z.; Yang, J.; Li, Y.; Gu, J., Specific recovery and in situ reduction of precious metals from waste to create MOF composites with immobilized nanoclusters. Ind Eng Chem Res 2017, 56, 13975. (32) Alqadami, A. A.; Naushad, M.; Alothman, Z. A.; Ghfar, A. A., Novel Metal-Organic Framework (MOF) Based Composite Material for the Sequestration of U(VI) and Th (IV) Metal Ions from Aqueous Environment. ACS Appl Mater Inter 2017, 9, 36026.



Page 28 of 29

(33) Liu, G.; Li, L.; Xu, D.; Huang, X.; Xu, X.; Zheng, S.; Zhang, Y.; Lin, H., Metal-organic

framework

preparation

using

magnetic

graphene

oxide-beta-cyclodextrin for neonicotinoid pesticide adsorption and removal. Carbohydr Polym 2017, 175, 584. (34) Yang, Q.; Ren, S.; Zhao, Q.; Lu, R.; Hang, C.; Chen, Z.; Zheng, H., Selective separation of methyl orange from water using magnetic ZIF-67 composites. Chem Eng J 2018, 333, 49. (35) Huang, L.; He, M.; Chen, B.; Hu, B., A mercapto functionalized magnetic Zr-MOF by solvent-assisted ligand exchange for Hg2+ removal from water. J Mater Chem A 2016, 4, 5159. (36) Valenzano, L.; Civalleri, B.; Chavan, S.; Bordiga, S.; Nilsen, M. H.; Jakobsen, S.; Lillerud, K. P.; Lamberti, C., Disclosing the Complex Structure of UiO-66 Metal Organic Framework: A Synergic Combination of Experiment and Theory. Chem Mater 2011, 23, 1700. (37) Yang, Q.; Wang, J.; Chen, X.; Yang, W.; Pei, H.; Hu, N.; Li, Z.; Suo, Y.; Li, T.; Wang, J., The simultaneous detection and removal of organophosphorus pesticides by a novel Zr-MOF based smart adsorbent. J Mater Chem A 2018, 6, 2184. (38) Lessa, E. F.; Nunes, M. L.; Fajardo, A. R., Chitosan/waste coffee-grounds composite: An efficient and eco-friendly adsorbent for removal of pharmaceutical contaminants from water. Carbohydr Polym 2018, 189, 257. (39) Teo, H. T.; Siah, W. R.; Yuliati, L., Enhanced adsorption of acetylsalicylic acid over hydrothermally synthesized iron oxide-mesoporous silica MCM-41 composites.


Page 29 of 29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


J Taiwan Inst Chem E 2016, 65, 591. (40) Meischl, F.; Schemeth, D.; Harder, M.; Köpfle, N.; Tessadri, R.; Rainer, M., Synthesis and evaluation of a novel molecularly imprinted polymer for the selective isolation of acetylsalicylic acid from aqueous solutions. J Environ Chem Eng 2016, 4, 4083. (41) Meng, M.; He, Z.; Li, Y.; Yan,Y.; Sun, F.; Liu, Y.; Liu, S., Fabrication of a novel cellulose acetate imprinted membrane assisted with chitosan-wrapped multi-walled carbon nanotubes for selective separation of salicylic acid from industrial wastewater. J Appl Polym Sci 2015, 42654, 1. (42) Arshadi, M.; Mousavinia, F.; Abdolmaleki, M. K.; Amiri, M. J.; Khalafi-Nezhad, A., Removal of salicylic acid as an emerging contaminant by a polar nano-dendritic adsorbent from aqueous media. J Colloid Interf Sci 2017, 493, 138. (43) Xiao, G.; Wen, R.; Liu, A.; He, G.; Wu, D., Adsorption performance of salicylic acid on a novel resin with distinctive double pore structure. J Hazard Mater 2017, 329, 77.


Highly Effective Removal of Pharmaceutical Compounds from

Recommend Documents