Facile Approach To Prepare Sulfur-Functionalized Magnetic Amide

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A facile approach to prepare sulfur-functionalized magnetic amide linked organic polymers for enhanced Hg(II) removal from water Lijin Huang, and Qin Shuai ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.9b00957 • Publication Date (Web): 17 Apr 2019 Downloaded from http://pubs.acs.org on April 20, 2019

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ACS Sustainable Chemistry & Engineering

A facile approach to prepare sulfur-functionalized magnetic amide linked organic polymers for enhanced Hg(II) removal from water Lijin Huang, Qin Shuai* Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, No. 388, Lumo Road, Hongshan District, Wuhan 430074, P. R. China *E-mail

address: [email protected]

1

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 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 Construction of adsorbents with specific porous structure and heteroatom-doped is significant for enhancing adsorption performance toward the contaminants. However, it is still a crucial task for selective adsorption with high affinity and fast uptake kinetic. Herein, we present a facile and cost-effective post-synthesis modification approach to fabricate a novel effective sulphur-doped magnetic amide linked organic polymer (S-MAOP), where AOP is chemically anchored on the surface of NH2 functionalized magnetic nanoparticles. The thionation process, e.g. transforming amide group (-C=O-NH-) into the thioamide group (-C=S-NH-), is illustrated by treating the MAOP with Lawesson’s reagent. The resultant S-MAOP exhibited much higher adsorption selectivity and affinity for Hg(II) uptake from water solution than the initial MAOP due to the introduction of thioamide groups in the network. In addition, by covalent anchoring polymer networks onto magnetic nanoparticles, recovery and regeneration of S-MAOP are greatly facilitated due to its good superparamagnetism. Furthermore, it also shows superior stability, of which the adsorption capacity was well maintained even after 5 cycles. The remarkable adsorption performance, good cycling stability and cost-efficient synthesis make S-MAOP a desirable adsorbent for contaminant removal.

Keywords: Porous organic polymers; Lawesson’s reactant; thioamide; mercury removal; magnetic composites; wastewater treatment 2


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INTRODUCTION Wastewater treatment, especially for the high-performance separation of toxic contaminant, is attractive to meet the challenges of environmental problems. Continuous exposure to industrial waste chemicals emitted in aqueous ecological systems, even in trace concentration, will affect the reproduction and health of wildlife.1 On the other hand, metal ions are hard biodegradation and high toxicity.2-3 Worse still, most of them are bioaccumulative, making it imperative and urgent to develop sustainable and effective technology for toxic metal ions removal. To achieve this aim, various technologies have been examined recently. Among them, adsorption has been proven as an attractive and versatile approach.4-6 It’s should be noted that the development of efficient and economical sorbents for adsorption is of decisive importance for this technique. To this aim, a wide range of porous materials, including activated carbon,7-8 grapheme oxides composites,9-10 zeolites,11 metal-organic frameworks (MOFs),12-13 and porous organic polymers (POPs),14-17 have been well explored. Among them, POPs, comprising organic linkers through strong covalent bonds, are a class of the most promising sorbents due to their high performance, excellent stability, environmental friendliness, and easy post-synthetic modifications to introduce specific functional groups.18-20 Remarkably, pioneering research works have confirmed that the introduction of sulfur heteroatom complexes into the networks of POPs contributes significantly to the improvement and selectivity of Hg(II) removal due to the strong soft-soft interactions between the sulfur and mercury.16-17, 3


21-23


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Generally, constructions of intrinsically S-functionalized POPs are usually based on sulfur-rich monomers (such as benzenethiol, thiophene-based monomers, sulfonated based monomers, thioether-based monomers, etc) or postsynthetic modification (e.g. thiol-ene “click” reaction, treatment with sodium hydrosulfide to introduce thiol-functionalized

groups,

complex/multistep processes.21,

etc.), 24

which

are

usually

costly

and

require

In addition, noble metal catalysts and/or high

reaction temperature associated with the synthesis of sulfur functionalized POPs limit their practical application gravely. On the other hand, it remains a challenge for the fast retrieval sorbents from sample matrix after adsorption, where tedious high-speed centrifugation or filtration is commonly used. Consequently, the development of an efficient and convenient method for retrieval the sorbents from sample matrix after adsorption is of paramount significance. Recently, the combination of POPs with magnetic nanoparticles (MNPs) has been demonstrated as a useful and outstanding method for the fast retrieval of sorbents after adsorption.23, 25-27 Many approaches have been utilized for the synthesis of magnetic POPs, such as embedding,28 layer-by-layer,29 encapsulation,30 and physical

mixing31.

Normally,

the

preparation

process

involves

boiling

1,3,5-trimethylbenzene or noble metal catalysts, which requires a long reaction time and consumes considerable amount of power.26,

32

The critical synthesis conditions

make it difficult to prepare magnetic POPs under mild conditions, especially under room temperature. Even more distressing is that the most of magnetic POPs prepared presently are combined with each other through physical interaction, i.e. embedding 4


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or mixing, which are less stable.25 Thus, more efforts should be focused on developing simple and cost-effective covalent linkage strategy for the preparation of magnetic POPs with high stability. Recently, numbers of polyamides comprised with abundant amide (-CONH-) functional groups (Am-MOP) on the pore surface have been synthesized advantageously under mild conditions and exploited for solid-phase extraction,33 CO2 sorption,18 and water purification.34 For example, Suresh et al. synthesized a highly stable amide functionalized POP based on the polymerization of trimesoyl chloride (TMC) and m-phenylenediamine (MPD) for selective CO2 uptake.18 Very recently, poly(TMC-TAPM)

was

successfully

tetrakis(4-aminophenyl)methane

prepared

(TAPM)

and

by

TMC

Liu as

et

al.

monomers

using for

the

polymerization.33 The prepared poly(TMC-TAPM) exhibited superior performance for glycopeptides enrichment due to its good hydrophilicity and special functional groups on the surface. In this regard, polyamides have enormous potential for the preparation of magnetic POPs and the applications of corresponding magnetic POPs have not yet been reported. In this work, we rationally designed and synthesized a robust sulfur-functionalized magnetic amide linked organic polymers (denoted as S-MAOP). Firstly, we modified the Fe3O4 nanoparticles with –NH2 functional groups (Fe3O4@SiO2-NH2, abbreviated as MNP-NH2), and then MAOP was prepared by means of copolymerization of MNP-NH2 with commercially available reagents, TMC and 4,4′-diaminobiphenyl (DBP), under mild condition. Subsequently, S-MAOP was obtained easily by treating 5



MAOP with Lawesson’s reactant (Scheme 1). The resultant S-MAOP was well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), and nitrogen adsorption-desorption measurement. Due to the introduction of sulfur, the material exhibited an enhanced adsorption capacity and selectivity for Hg(II) capture from the water. Besides, the S-MAOP can be retrieved easily and rapidly from the water after adsorption via a magnet, indicating its great potential for the metal ions capture from environmental samples. EXPERIMENTAL Materials Trimesoyl chloride (TMC), Lawesson’s reactant, triethylamine (99%), and 4,4′-diaminobiphenyl (BDA) were purchased from Aladdin (Shanghai, China). Acetone and toluene were obtained from Sigma-Aldrich and dried prior to use. MNP-NH2 was synthesized according to the reported method.35 Tetraethoxysilane (TEOS) and amino propyl triethoxysilane (APTES) were purchased from the organic silicon material company of Wuhan University (Wuhan, China). Preparation of MAOPs Typically, 100 mg of the as-synthesized MNP-NH2 was added into 100 mL of acetone and subjected to ultrasound for 20 min. Subsequently, a solution of TMC (265 mg, 1.0 mmol) in 20 mL acetone was added through a constant-pressure dropping funnel. The reaction solution was kept in ice-water bath under stirring. After 30 min, a mixture of BDA (1.5 equiv) and triethylamine (1.5 equiv, 0.1 mL) in acetone was added 6


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drop-wise. The reaction was then stirred continuously for 12 h at room temperature. The resultants were segregated with the help of a magnet and washed several times with ethanol and water, then freeze-dried to afford a grey powder. Synthesis of S-MAOP The preparation of S-MAOP was performed in a 100 mL glass round-bottom flask. 200 mg of Lawesson’s reactant was added into the suspension of as-prepared MAOP (100 mg) in 50 mL toluene. The mixture was kept reflux for 6 h under stirring. After cooling to room temperature, the product was washed several times with NaHCO3 solution, water and ethanol, and finally dried overnight at 50 oC under vacuum. The yield product was denoted as S-MAOP. Characterization The morphology study of the as-prepared materials was performed on an SEM (X-650, Hitachi, Tokyo, Japan) and TEM (JEM-2010 electron microscope, Tokyo, Japan). Energy-dispersive X-ray analysis (EDX) was also achieved on SEM. The saturation magnetization of composites was measured by a PPMS-9 vibrating sample magnetometer (VSM, QUANTOM, USA). The data of Fourier transform infrared spectrometer (FT-IR) spectra of the composites were collected by a NEXUS 870 spectroscopy (Thermo, Madison, USA) over the range of 4000-400 cm-1 using KBr pellets, which were prepared from mixtures of KBr and the sample (weight ratio 200/1) with a hydraulic machine. The measurement of N2 adsorption/desorption isotherms was carried out on the ASAP 2020 apparatus (Micromeritics, USA) at 77 K. The surface areas of composites were calculated via the Brunauer-Emmet-Teller 7



(BET) method. Thermodynamic analysis was evaluated on a PE diamond TG/DTA 6300 (USA) in N2 atmosphere with a heating rate of 10 oC min-1. X-ray photoelectron spectroscopy (XPS) measurement was accomplished using ESCALAB 250 XPS (ThermoFisher, Al Kα). The crystal structure of the samlpes were examined by a XRD instrument (Bruker D8, Germany) with Cu Kα radiation. The concentration of target metal ions was acquired using an Intrepid XSP Radial inductively coupled plasma optical emission spectrometry (ICP-OES, Thermo, Waltham, MA, USA) or inductively coupled plasma mass spectrometry (ICP-MS, Elan DRC-e, PerkinElmer, USA). Adsorption/desorption studies The investigation for the metal ions adsorption performance of S-MAOP was studied using batch experiments, where all experiments were carried out in triplicates. In particular, the adsorption procedure is described as follows: 5 mg S-MAOP was added into 10 mL solutions containing varied initial concentration, i.e. 50-500 mg L-1. 0.1 M NaOH or HCl was employed to adjust the solution pH. After 60 min, the sorbent was isolated from solution with the help of a magnet. Both of initial solution and the supernatant were submitted to ICP-OES/ICP-MS for detection. The effect of incubation time was carried out by adding 50 mg S-MAOP into 50 mL Hg(II) (50 mg L-1) solution at pH 3 and 25 oC. The effect of adsorbent dosages was carried out by employing different amouts of S-MAOP (2, 5, 10, 15, and 20 mg) wih 20 mL Hg(II) solution at pH 3 and 25 oC. The mixed solution of hydrochloric acid (0.5 M) containing 1% thiourea (m/V) was utilized to release the adsorbed Hg(II) from 8


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S-MAOP for recycled experiment. RESULTS AND DISCUSSION Preparation and characterization of S-MAOP The procedure for the facile synthesis of S-MAOP is illustrated in Scheme 1. Remarkably, MNP-NH2 was obtained via a controllable sol-gel process primarily,35 which not only enhanced the pH stability of Fe3O4 NPs, but also made it possible for the condensation of TMC and BDA to form amide network on the surface of MNP-NH2. The preparation of S-MAOP was carried out by treating MAOP with Lawesson’s reactant, which has been widely used for the facile and efficient synthesis of thioketones, thioesters and thioamides from relevant ketones, esters, and amides in a high yield,36 making it possible to adsorb metal ions with enhanced adsorption capacity and selectivity. FT-IR spectra of monomers, MAOP and S-MAOP provided direct proofs for the successful synthesis (Figure 1(a)). For the sample of MNP-NH2, the peak around 1080 cm-1 can be ascribed to Si-O stretching vibration.[37-38] Compared with that of TMC and BDA, the new peaks appeared at 1663 and 3230 cm-1, which were corresponding to the stretching vibration of C=O and N-H in the −CONH− groups.18 In addition, peaks at 1514 and 1398 cm−1 contributed to N-H bending and C-N stretching vibration were also observed,33 indicating the successful synthesis of MAOP. Compared with that of MAOP, a new peak appeared at 1110 cm-1, which is conditionally assigned to the stretching vibrations of C=S bond,39-40 demonstrating the S-MAOP was obtained by treating MAOP with Lawesson’s reactant. The successful 9



synthesis of S-MAOP was further confirmed by XPS technique. As illustrated in Figure S1, Fe, O, Si, N, C, O and S were presented in the sample of S-MAOP, offering the strong evidence of successful thionation of amides using Lawesson’s reagent. The peaks at 399.9 and 164.2 eV were assigned to the N 1s and S 2p in the -CS-NH- groups,41 respectively, confirming the successful transformation of -CONHinto -CSNH- groups. Further attention was paid to the investigation of the porous structure of MAOP and S-MAOP. The investigation was based on the N2 adsorption-desorption measurement and the results were shown in Figure 1(b). The experimental values were calculated to be 54.7 and 55.7 m2 g-1 for MAOP and S-MAOP using the BET model, and a similar pore size distribution of them around 1.6 nm was obtained by Barrett–Joyner–Halenda (BJH) analysis. Furthermore, after treating with Lawesson’s reagent, a little change was observed for pore volume of MAOP (0.092 cm3 g-1) and S-MAOP (0.093 cm3 g-1). All these results indicated the porous structure of the material was well maintained after the transformation. To achieve more features of the morphology before and after the conversion, these two composites were further characterized by TEM (Figure 2). It can be found that the MNPs were embedded into amide polymers networks through the TEM image of MAOP. Interestingly, no significant difference between these two materials was observed. Nevertheless, strong evidence for the presence of Fe, Si, O, C, N and S in S-MAOP sample (Figure 2 (c)) was found when elemental mapping analysis was performed. And the EDX data suggested the weight percentage of sulphur in the 10


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sample was ~11.7%, where the thioamide content in S-MAOP was about 3.3 mmol g-1. In addition, the XRD patterns (Figure S2) appeared at 30.3o and 35.7o corresponding to Fe3O4 (JCPDS no. 19-0629) were observed for MNP-NH2, MAOP and S-MAOP, providing further support for the successful preparation of S-MAOP. The thermal stability of the magnetic composites was investigated by TGA under N2 atmosphere. As shown in Figure 3, MNPs could maintain virtually its weight in the tested temperature range (i.e. R.T. to 800 oC) mainly due to its high stability. There was about 8% weight loss for MAOP between 100 and 200 oC, which corresponds to the continuously release of adsorbed moisture/solvent entrapped in its pores.18 And then it suffered a sharp weight loss at about 500 oC due to the decomposition of the organic skeleton and conversion to porous carbon. However, compared with that of MAOP, S-MAOP showed a ~5% weight loss at temperature around 250 oC, which may be attributed to the decomposition of thioamide group, similar to the findings of previous work for thioamide functionalized polymer.39 The feature weight loss at about 500 oC can be caused by the degradation of the polymer backbone.18 These results further corroborated the successful synthesis of S-MAOP and its high thermal stability. The magnetization curves of MNPs, MAOP and S-MAOP are shown in Figure 4 and all the samples turned out to be superparamagnetic without apparent hysteresis, remanence, and coercivity. Compared with that of MNPs (48 emu g-1), the saturation magnetization of MAOP was determined to be 21 emu g-1, which showed a decrease due to the modification of amide polymers. After treating with Lawesson’s reactant, 11



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the saturation magnetization of S-MAOP exhibited a further reduce bringing it to 15 emu g-1. Nevertheless, it is still strong enough for magnetic separation, which enabled the isolation of S-MAOP from solution by an external magnetic field to be easily realized. Adsorption performance Large amounts of thioamide functional groups presented in the porous structure of S-MAOP makes it possess a great potential for toxic metal ions removal. To demonstrate the adsorption activity, the adsorption of S-MAOP for Hg(II) was investigated. As the pH of the solution plays a decisive role that affects the existing forms of adsorbents and metal ions simultaneously, which will further affect the process of adsorption. Thus, the influence of solution pH (2.0-7.0) was investigated. As shown in Figure 5, it is apparent that the value of solution pH exerts a significant influence on the adsorption of Hg(II). Notably, compared with that of MAOP, the adsorption ability of S-MAOP toward Hg(II) was greatly improved, indicating that the introduction of thioamide can improve the affinity of the sorbent toward target ions due to the strong interaction between Hg and S. Since the initial concentration of Hg(II) employed was at a low level (10 mg L-1), all of the Hg(II) can be adsorbed onto S-MAOP over a wide range of pH due to the sufficient sites available for Hg(II) capture.

These

results

are

in

line

with

previous

studies

that

taking

sulphur-functionalized materials as Hg(II) adsorbents.42-43 The effect of sorbent dosage on the adsorption capacities were evaluated by adding different amount of S-MAOP into the Hg(II) solutions with constant concentration 12


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and volume, i.e. 2, 5, 10, 15 and 20 mg S-MOAP were added into 20 mL solution that containing 300 mg L-1 Hg(II) at pH=3 and 25 oC. As shown in Figure S3, the removal efficiency for Hg(II) showed a increase tendency as the sorbent addition increased, but the adsorption capacity for Hg(II) showed a gradual descending. The results indicated the higher sorbent dosage was more favorable for Hg(II) adsorption than lower ones. And the as-prepared S-MAOP can achieve pretty high removal efficiency even with a low sorbent dosage (0.5 g L-1). Several co-existing metal ions may present in Hg(II) containing samples. For the practical utility of adsorbents, selectivity may be one of the most important aspects. Thus, the adsorption experiment of S-MAOP towards Hg(II) with various co-existing ions (e.g. Cu2+, Co2+, Cd2+, Cr3+, Mn2+, Ni2+, Pb2+ and Zn2+) was carried out. As shown in Figure 6, the removal efficiency of Hg(II) from the mentioned mixture was found to be >99%, but that of other ions were very low, which can be due to the strong interaction between Hg and S. According to the Pearson’s soft-hard acid-base (SHAB) theory, soft base (S) is more likely to combine with soft acid (Hg2+) rather than borderline (such as Pb2+) or hard acid (such as Ca2+).44 Meanwhile, the solubility product constant (Ksp) of Hg-S is lowest (Ksp = 4.0×10-53) among all these co-existence ions, where CdS (1.4×10-29), ZnS (2.9×10-25), CuS (6.3×10-36), and PbS (9.04×10-29).45-47 It can therefore be assumed that the S-MAOP has a desirable selectivity for Hg(II) over other heavy or transition metal ions, demonstrating the promising application of S-MAOP in selective adsorption/recovery of Hg(II). For practical application, the presence of other anions and cations in the natural 13



water may have negative effect on the adsorption capacity. Hence, the influence of common anions (Cl-, NO3- and SO42-) and cations (Na+, K+ and Ca2+) were investigated. As shown in Figure S4, S-MAOP exhibited excellent affinity toward Hg(II). The quantitative sorption of Hg(II) could be achieved virtually when the concentration of coexisting anions and cations were 10 mmol L-1. However, when their concentrations were up to 100 mmol L-1, the adsorption performance of S-MOAP, to some extent, was diminished. And the adversely effects varied for individual ions. For anions, Cl- exhibited the greatest potential impact on the adsorption due to the fact that Cl- can form multiple complexes with Hg(II) (i.e. HgCl2, HgCl3-, and HgCl42-). On the other hand, the divalent cation Ca2+ exhibited a greater adverse effect than that of monovalent cations Na+ and K+, which may be ascribed to the competition for active adsorption sites, resulting in a descending adsorption.48 To assess the adsorption process of Hg(II) onto S-MAOP, kinetic studies were carried out by time-dependent experiments. The influence of incubating time on the adsorption was depicted in Figure 7(a). Surprisingly, the adsorption increase sharply and the incubated time of 2 min was found to be sufficient to reach equilibrium when initial Hg(II) concentration was 50 mg L-1. The data were clarified that the S-MAOP has a rapid adsorption kinetic for Hg(II) capture, which may be due to the combined effect of its porous structure, favorable hydrophilcity, and good dispersity,33 indicating that it has great potential for practical application. The kinetic data obtained from adsorption experiment were fitted to 14


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pseudo-second-order kinetic model using Equation (1):

t t 1   Qt Qe K 2Qe2

Eq. (1)

Where Qe and Qt (mg g-1) are the amounts of Hg(II) at equilibrium and at time t (min), respectively, and K2 (g mg-1 min-1) is the adsorption rate constants of pseudo-second order. A good linear fitting of the experimental data between t/Qt and t was found, and the value of K2 was found to be 28.97 g mg-1 min-1. These findings indicated the adsorption of Hg(II) in this study followed the pseudo-second-order model and intraparticle diffusion was the rate-determining step of the adsorption.17 The adsorption isotherm is a general but significant approach to determine the maximum adsorption capacity of adsorbent. The adsorption isotherm of S-MAOP for Hg(II) was obtained by adding S-MAOP into Hg(II) solution with different concentrations (50-600 mg L-1). As shown in Figure 8, the adsorption increases gradually within the initial concentration range from 50 to 500 mg L-1 and reaches equilibrium finally. The value of maximum adsorption capacity was found to be 512 mg g-1, outperforming some of previously reported materials (Table 1). The experimental data were analysed using the Langmuir model and the linear plot of Ce/qe versus Ce shows that the sorption obeys the Langmuir model well (Figure 8) (R2>0.999), demonstrating that the sorption process was monolayer.49-50 Meanwhile, according to the recently research, partition coefficient can better represent the performance of an adsorbent than the adsorption capacity or removal efficiency, whereas the latter can be altered when the operating conditions change.51-52 To this 15



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end, the partition coefficient, which represents the ration of analyte concentration on/in the sorbent to that of in the liquid phase at equilibrium, was computed to assess its actual performance.53-54 As shown in table 1, the saturated capacity would be easily achieved when the initial concentration is high, but it will drive down the partition coefficient due to a large number of Hg(II) ions retaining in solution. Inspiringly, S-MAOP performed reasonably well with a high partition coefficient (2.05×104 mg g−1 µM−1) and adsorption capacity (512 mg g-1) simultaneously, demonstrating it has a strong affinity for Hg(II) capture for real-world applications. High adsorption performance of S-MAOP toward Hg(II) was caused by the strong interaction between S atom and Hg, which were confirmed by XPS and FT-IR analysis. The XPS spectra of initial S-MAOP and the sample after adsorption (denoted as Hg-S-MAOP) were presented in Figure S5. For the pristine S-MAOP (Figure S5), peaks at 105.3 and 101.4 eV corresponding to Hg 4f7/2 and 4f5/2 were not observed.56 However, these two peaks appeared in the spectrum of Hg-S-MAOP sample (Figure S5 and Figure S6 (c)), providing convincing evidence for the adsorption of Hg(II) onto S-MAOP. In addition, compared with that of S-MAOP (Figure S6(a), 163.1 eV), the peak of S 2p moved a little to a high binding energy (163.5 eV) after Hg loading (Figure S6(b)), indicating S in the S-MAOP was bound to Hg(II).23 Furthermore, the appearance of the peak at 1379 cm-1 corresponding to Hg-S in the FT-IR spectrum of Hg loading S-MAOP (Figure S7) also gave distinct evidence for the successful Hg(II) trapping.23 For

examining

whether

the

sorbents

could

16


be

regenerated,

five

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adsorption-desorption cycles were performed under optimum conditions. The results, as shown in Figure 9, indicate that no significant reduction in adsorption capacity was found compared with that of pristine S-MAOP. This reusability study proved that the adsorbent is highly stable and can be used for many cycles. To further investigate the effect of recycling on the structural change, TEM characterization (Figure S8), FT-IR and N2 adsorption-desorption experiment (Figure S7 and Figure S9) were carried out for the reused S-MAOP. The results showed that the S-MAOP has high stability and can be used as a cost-efficient sorbent for heavy metal ions removal with superior performance. For practical application, the production cost of the S-MAOP needs to be considered. Notably, a rough cost estimating demonstrated the cost for S-MAOPs was ~0.023 $ g-1 (Table S1), which is cheaper than other adsorbents, liking MOFs >10 $ g-1, activated carbon at 0.085-1.78 $ g-1 and zeolite at 0.85-5.14 $ g-1.53,57 In addition, it should be noted that the price presented here for S-MAOP is far too high, which was preliminary estimates basing on lab experiment, since industrial scale production will drive the price down. Furthermore, the cost will be reduced due to its good regeneration ability. Taking account of its good stability, the as-prepared S-MAOPs can be used as a cost-effective adsorbent for environmental remediation. CONCLUSIONS In summary, a general, facile and effective methodology for the construction of sulphur functionalization materials to enhance the adsorption performance for heavy metal ions has been explored in this work. By treating the MAOP with Lawesson’s 17



reactant, thioamide functional groups were incorporated into the porous polymeric networks. Due to the essential and strong soft−soft interaction between Hg and S, the S-MAOP exhibited excellent adsorption performance for the capture of Hg(II) from water (Qmax=512 mg g-1), surpassing that of MAOP greatly. The S-MAOP exhibited very fast Hg(II) uptake kinetics (K2= 28.97 g mg-1 min-1) and can be conveniently separated from water solution under the external magnetic field. Furthermore, the prepared S-MAOP showed good chemical stability, which can be recycled many times. This strategy thereby affords an attractive route for the synthesis of sulphur functionalized materials with highly efficient performance and provides the ways to circumvent the challenge associated with the harsh conditions in preparation of sulphur functionalized materials. ASSOCIATED CONTENT Supporting Information Materials characterization and other data. This material is available free of charge via the Internet at http://pubs.acs.org. Additional information, including SEM image of S-MAOP; XRD patterns of different samples; effect of sorbent dosage; Effect of common coexisting ions; XPS spectra of as-prepared S-MAOP and Hg(II) loaded sample; High-resolution spectra of S 2p for S-MAOP, Hg loaded sample, and high-resolution spectra of Hg 4f; FT-IR spectra of as-prepared S-MAOP, Hg loaded sample and the reused sample; the TEM image for the reused S-MAOP; N2 adsorption-desorption isotherms of S-MAOP after 5 cycles. AUTHOR INFORMATION 18


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Corresponding Author E-mail

address: [email protected].

ORCID Lijin Huang: 0000-0002-0555-7823 Notes The authors declare no competing financial interest. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (21806148) and Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (Grant No.CUG170102; Grant No. CUG180610). REFERENCES (1) Zou, Y.; Wang, X.; Khan, A.; Wang, P.; Liu, Y.; Alsaedi, A.; Hayat, T.; Wang, X. Environmental Remediation and Application of Nanoscale Zero-Valent Iron and Its Composites for the Removal of Heavy Metal Ions: A Review. Environ. Sci. Technol. 2016, 50 (14), 7290-304, DOI: 10.1021/acs.est.6b01897. (2) Crockett, M. P.; Evans, A. M.; Worthington, M. J.; Albuquerque, I. S.; Slattery, A. D.; Gibson, C. T.; Campbell, J. A.; Lewis, D. A.; Bernardes, G. J.; Chalker, J. M. Sulfur-Limonene Polysulfide: A Material Synthesized Entirely from Industrial By-Products and Its Use in Removing Toxic Metals from Water and Soil. Angew. Chem. Int. Ed. 2016, 55 (5), 1714-1718, DOI: 10.1002/anie.201508708. (3) Ai, K.; Ruan, C.; Shen, M.; Lu, L. MoS2 Nanosheets with Widened Interlayer Spacing for High-Efficiency Removal of Mercury in Aquatic Systems. Adv. Funct. 19



Page 20 of 41

Mater. 2016, 26 (30), 5542-5549, DOI: 10.1002/adfm.201601338. (4) Yu, J.-G.; Yue, B.-Y.; Wu, X.-W.; Liu, Q.; Jiao, F.-P.; Jiang, X.-Y.; Chen, X.-Q. Removal of Mercury by Adsorption: A review. Environ. Sci. Pollut. Res. Int. 2016, 23 (6), 5056-5076, DOI: 10.1007/s11356-015-5880-x. (5) Chen, D.; Zhu, H.; Yang, S.; Li, N.; Xu, Q.; Li, H.; He, J.; Lu, J. Micro-Nanocomposites in Environmental Management. Adv. Mater. 2016, 28 (47), 10443-10458, DOI: 10.1002/adma.201601486. (6) Das, R.; Vecitis, C. D.; Schulze, A.; Cao, B.; Ismail, A. F.; Lu, X.; Chen, J.; Ramakrishna, S. Recent Advances in Aanomaterials for Water Protection and Monitoring.

Chem.

Soc.

Rev.

2017,

46

(22),

6946-7020,

DOI:

10.1039/c6cs00921b. (7) Gong, K.; Hu, Q.; Yao, L.; Li, M.; Sun, D.; Shao, Q.; Qiu, B.; Guo, Z. Ultrasonic Pretreated Sludge Derived Stable Magnetic Active Carbon for Cr(VI) Removal from Wastewater. ACS Sustain. Chem. Eng. 2018, 6 (6), 7283-7291, DOI: 10.1021/acssuschemeng.7b04421. (8) Ma, Q.; Yu, Y.; Sindoro, M.; Fane, A. G.; Wang, R.; Zhang, H. Carbon-Based Functional Materials Derived from Waste for Water Remediation and Energy Storage. Adv. Mater. 2017, 29 (13), 1605361, DOI: 10.1002/adma.201605361. (9) Xu, X.; Zou, J.; Teng, J.; Liu, Q.; Jiang, X.-Y.; Jiao, F.-P.; Yu, J.-G.; Chen, X.-Q. Novel High-Gluten Flour Physically Cross-Linked Graphene Oxide Composites: Hydrothermal Fabrication and Adsorption Properties for Rare Earth Ions. Ecotoxicol. Environ. Saf. 2018, 166, 1-10, DOI: 10.1016/j.ecoenv.2018.09.062. 20


Page 21 of 41 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


(10) Wang, Z.; Li, X.; Liang, H.; Ning, J.; Zhou, Z.; Li, G. Equilibrium, Kinetics and Mechanism of Au3+, Pd2+ and Ag+ Ions Adsorption from Aqueous Solutions by Graphene Oxide Functionalized Persimmon Tannin. Mater. Sci. Eng., C 2017, 79, 227-236, DOI: 10.1016/j.msec.2017.05.038. (11) Luo, H.; Law, W. W.; Wu, Y.; Zhu, W.; Yang, E.-H. Hydrothermal Synthesis of Needle-Like Nanocrystalline Zeolites from Metakaolin and Their Applications for Efficient Removal of Organic Pollutants and Heavy Metals. Microporous Mesoporous Mater. 2018, 272, 8-15, DOI: 10.1016/j.micromeso.2018.06.015. (12) Li, J.; Wang, X.; Zhao, G.; Chen, C.; Chai, Z.; Alsaedi, A.; Hayat, T.; Wang, X. Metal-Organic Framework-Based Materials: Superior Adsorbents for The Capture of Toxic and Radioactive Metal Ions. Chem. Soc. Rev. 2018, 47 (7), 2322-2356, DOI: 10.1039/c7cs00543a. (13) Kumar, P.; Pournara, A.; Kim, K.-H.; Bansal, V.; Rapti, S.; Manos, M. J. Metal-Organic

Frameworks:

Challenges

and

Opportunities

for

Ion-Exchange/Sorption Applications. Prog. Mater. Sci. 2017, 86, 25-74, DOI: 10.1016/j.pmatsci.2017.01.002. (14) Alsbaiee, A.; Smith, B. J.; Xiao, L.; Ling, Y.; Helbling, D. E.; Dichtel, W. R. Rapid Removal of Organic Micropollutants from Water by A Porous β-Cyclodextrin

Polymer.

Nature

2016,

529

(7585),

190-194,

DOI:

10.1038/nature16185. (15) Demir, S.; Brune, N. K.; Van Humbeck, J. F.; Mason, J. A.; Plakhova, T. V.; Wang, S.; Tian, G.; Minasian, S. G.; Tyliszczak, T.; Yaita, T.; Kobayashi, T.; 21



Page 22 of 41

Kalmykov, S. N.; Shiwaku, H.; Shuh, D. K.; Long, J. R. Extraction of Lanthanide and

Actinide

Ions

from

Aqueous

Mixtures

Using

a

Carboxylic

Acid-Functionalized Porous Aromatic Framework. ACS Cent. Sci. 2016, 2 (4), 253-65, DOI: 10.1021/acscentsci.6b00066. (16) Ding, S. Y.; Dong, M.; Wang, Y. W.; Chen, Y. T.; Wang, H. Z.; Su, C. Y.; Wang, W. Thioether-Based Fluorescent Covalent Organic Framework for Selective Detection and Facile Removal of Mercury(II). J. Am. Chem. Soc. 2016, 138 (9), 3031-3037, DOI: 10.1021/jacs.5b10754. (17) Aguila, B.; Sun, Q.; Perman, J. A.; Earl, L. D.; Abney, C. W.; Elzein, R.; Schlaf, R.; Ma, S. Efficient Mercury Capture Using Functionalized Porous Organic Polymer. Adv. Mater. 2017, 29 (31), 1700665, DOI: 10.1002/adma.201700665. (18) Suresh, V. M.; Bonakala, S.; Atreya, H. S.; Balasubramanian, S.; Maji, T. K. Amide Functionalized Microporous Organic Polymer (Am-MOP) for Selective CO2 Sorption and Catalysis. ACS Appl. Mater. Interfaces 2014, 6 (7), 4630-4637, DOI: 10.1021/am500057z. (19) Fang, Q.; Wang, J.; Gu, S.; Kaspar, R. B.; Zhuang, Z.; Zheng, J.; Guo, H.; Qiu, S.; Yan, Y. 3D Porous Crystalline Polyimide Covalent Organic Frameworks for Drug Delivery. J. Am. Chem. Soc. 2015, 137 (26), 8352-8355, DOI: 10.1021/jacs.5b04147. (20) Tan, M. X.; Sum, Y. N.; Ying, J. Y.; Zhang, Y. A Mesoporous Poly-Melamine-Formaldehyde Polymer as A Solid Sorbent for Toxic Metal Removal.

Energy

Environ.

Sci.

2013,

6

22


(11),

3254-3259,

DOI:

Page 23 of 41 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


10.1039/C3EE42216J. (21) Li, B.; Zhang, Y.; Ma, D.; Shi, Z.; Ma, S. Mercury Nano-trap for Effective and Efficient Removal of Mercury(II) from Aqueous Solution. Nat. Commun. 2014, 5, 5537, DOI: 10.1038/ncomms6537. (22) Li, X. P.; Bian, C. Q.; Meng, X. J.; Xiao, F. S. Design and Synthesis of An Efficient Nanoporous Adsorbent for Hg2+ and Pb2+ Ions in Water. J Mater. Chem. A 2016, 4 (16), 5999-6005, DOI: 10.1039/c6ta00987e. (23) Huang, L. J.; Peng, C. Y.; Cheng, Q.; He, M.; Chen, B. B.; Hu, B. Thiol-Functionalized Magnetic Porous Organic Polymers for Highly Efficient Removal of Mercury. Ind. Eng. Chem. Res. 2017, 56 (46), 13696-13703, DOI: 10.1021/acsJecr.7b03093. (24) Huang, N.; Zhai, L.; Xu, H.; Jiang, D. Stable Covalent Organic Frameworks for Exceptional Mercury Removal from Aqueous Solutions. J. Am. Chem. Soc. 2017, 139 (6), 2428-2434, DOI: 10.1021/jacs.6b12328. (25) Zhang, W.; Liang, F.; Li, C.; Qiu, L. G.; Yuan, Y. P.; Peng, F. M.; Jiang, X.; Xie, A. J.; Shen, Y. H.; Zhu, J. F. Microwave-Enhanced Synthesis of Magnetic Porous Covalent Triazine-Based Framework Composites for Fast Separation of Organic Dye from Aqueous Solution. J. Hazard. Mater. 2011, 186 (2-3), 984-990, DOI: 10.1016/j.jhazmat.2010.11.093. (26) Tan, J.; Namuangruk, S.; Kong, W.; Kungwan, N.; Guo, J.; Wang, C. Manipulation

of

Amorphous-to-Crystalline

Transformation:

Towards

the

Construction of Covalent Organic Framework Hybrid Microspheres with NIR 23



Page 24 of 41

Photothermal Conversion Ability. Angew. Chem. Int. Ed. 2016, 55 (45), 13979-13984, DOI: 10.1002/anie.201606155. (27) Wang, J.; Li, J.; Gao, M.; Zhang, X. Self-Assembling Covalent Organic Framework Functionalized Magnetic Graphene Hydrophilic Biocomposites as An Ultrasensitive Matrix for N-Linked Glycopeptide Recognition. Nanoscale 2017, 9 (30), 10750-10756, DOI: 10.1039/c7nr02932b. (28) Shekhah, O.; Wang, H.; Kowarik, S.; Schreiber, F.; Paulus, M.; Tolan, M.; Sternemann, C.; Evers, F.; Zacher, D.; Fischer, R. A.; Wöll, C. Step-by-Step Route for the Synthesis of Metal−Organic Frameworks. J. Am. Chem. Soc. 2007, 129 (49), 15118-15119, DOI: 10.1021/ja076210u. (29) Silvestre, M. E.; Franzreb, M.; Weidler, P. G.; Shekhah, O.; Wöll, C. Magnetic Cores with Porous Coatings: Growth of Metal-Organic Frameworks on Particles Using Liquid Phase Epitaxy. Adv. Funct. Mater. 2013, 23 (9), 1210-1213, DOI: 10.1002/adfm.201202078. (30) Lu, G.; Li, S. Z.; Guo, Z.; Farha, O. K.; Hauser, B. G.; Qi, X. Y.; Wang, Y.; Wang, X.; Han, S. Y.; Liu, X. G.; DuChene, J. S.; Zhang, H.; Zhang, Q. C.; Chen, X. D.; Ma, J.; Loo, S. C. J.; Wei, W. D.; Yang, Y. H.; Hupp, J. T.; Huo, F. W. Imparting Functionality to A Metal-Organic Framework Material by Controlled Nanoparticle Encapsulation. Nature Chem. 2012, 4 (4), 310-316, DOI: 10.1038/nchem.1272. (31) Huo, S. H.; Yan, X. P. Facile Magnetization of Metal-Organic Framework MIL-101

for

Magnetic

Solid-Phase

Extraction

24


of

Polycyclic

Aromatic

Page 25 of 41 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


Hydrocarbons in Environmental Water Samples. Analyst 2012, 137 (15), 3445-3451, DOI: 10.1039/c2an35429b. (32) Zhou, L.; Hu, Y.; Li, G. Conjugated Microporous Polymers with Built-In Magnetic Nanoparticles for Excellent Enrichment of Trace Hydroxylated Polycyclic Aromatic Hydrocarbons in Human Urine. Anal. Chem. 2016, 88 (13), 6930-6938, DOI: 10.1021/acs.analchem.6b01708. (33) Liu, Z.; Ou, J.; Wang, H.; You, X.; Ye, M. Synthesis and Characterization of Hydrazide-Linked and Amide-Linked Organic Polymers. ACS Appl. Mater. Interfaces 2016, 8 (46), 32060-32067, DOI: 10.1021/acsami.6b11572. (34) Tan, Z.; Chen, S.; Peng, X.; Zhang, L.; Gao, C. Polyamide Membranes with Nanoscale Turing Structures for Water Purification. Science 2018, 360 (6388), 518-521, DOI: 10.1126/science.aar6308. (35) Zhang, J.; Zhai, S.; Li, S.; Xiao, Z.; Song, Y.; An, Q.; Tian, G. Pb(II) Removal of Fe3O4@SiO2–NH2 Core–shell Nanomaterials Prepared via A Controllable Sol–gel Process. Chem. Eng. J. 2013, 215-216, 461-471, DOI: 10.1016/j.cej.2012.11.043. (36) Jesberger, M.; Davis, T. P.; Barner, L. Applications of Lawesson’s Reagent in Organic and Organometallic Syntheses. Synthesis 2003, 2003 (13), 1929-1958, DOI: 10.1055/s-2003-41447. (37) Shi, Z.; Xu, C.; Lu, P.; Fan, L.; Liu, Y.; Wang, Y.; Liu, L.; Li, L. Preparation and The Adsorption Ability of Thiolated Magnetic Core-Shell Fe3O4@SiO2@C-SH for Removing Hg2+ in Water Solution. Mater. Lett. 2018, 225, 130-133, DOI: 10.1016/j.matlet.2018.04.098. 25



(38) Wang, X.; Zhang, Z.; Zhao, Y.; Xia, K.; Guo, Y.; Qu, Z.; Bai, R. A Mild and Facile Synthesis of Amino Functionalized CoFe2O4@SiO2 for Hg(II) Removal. Nanomaterials 2018, 8 (9), 673, DOI: 10.3390/Nano8090673. (39) Mason, C. R.; Maynard-Atem, L.; Al-Harbi, N. M.; Budd, P. M.; Bernardo, P.; Bazzarelli, F.; Clarizia, G.; Jansen, J. C. Polymer of Intrinsic Microporosity Incorporating Thioamide Functionality: Preparation and Gas Transport Properties. Macromolecules 2011, 44 (16), 6471-6479, DOI: 10.1021/ma200918h. (40) Zinenko, T. N.; Starodub, V. A.; Kazachkov, A. R. Metal Isotrithionedithiolates as Synthetic Metals. Russ. J. Coord. Chem. 2003, 29 (6), 400-407, DOI: 10.1023/a:1024030110596. (41) Darabi, H. R.; Jafar Tehrani, M.; Aghapoor, K.; Mohsenzadeh, F.; Malekfar, R. A New Protocol for the Carboxylic Acid Sidewall Functionalization of Single-Walled Carbon Nanotubes. Appl. Surf. Sci. 2012, 258 (22), 8953-8958, DOI: 10.1016/j.apsusc.2012.05.126. (42) Yee, K. K.; Reimer, N.; Liu, J.; Cheng, S. Y.; Yiu, S. M.; Weber, J.; Stock, N.; Xu, Z. Effective Mercury Sorption by Thiol-Laced Metal-Organic Frameworks: In Strong Acid and the Vapor Phase. J. Am. Chem. Soc. 2013, 135 (21), 7795-7798, DOI: 10.1021/ja400212k. (43) Huang, L. J.; He, M.; Chen, B. 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 (14), 5159-5166, DOI: 10.1039/c6ta00343e. (44) Parr, R. G.; Pearson, R. G. Absolute Hardness: Companion Parameter to 26


Page 26 of 41

Page 27 of 41 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


Absolute Electronegativity. J. Am. Chem. Soc. 1983, 105 (26), 7512-7516, J. Am. Chem. Soc. 1983, 105 (26), 7512-7516, DOI: 10.1021/ja00364a005. (45)

Zawadzka,

A.

M.;

Crawford,

R.

L.;

Paszczynski,

A.

J.

Pyridine-2,6-bis(thiocarboxylic acid) Produced by Pseudomonas Stutzeri KC Reduces Chromium(VI) and Precipitates Mercury, Cadmium, Lead and Arsenic. Biometals 2007, 20 (2), 145-158, DOI: 10.1007/s10534-006-9022-2. (46) Hsu, S.-K.; Chang, Z.-J.; Chang, S.-M. Fluorescent Determination of Copper(II) in Industrial Wastewater Using Thiol-Capped Cadmium Sulfide–Zinc Sulfide Quantum Dots as the Probe. Anal. Lett. 2018, 51 (4), 547-563, DOI: 10.1080/00032719.2017.1338715. (47) Zhu, Y. F.; Zhou, G. H.; Ding, H. Y.; Liu, A. H.; Lin, Y. B.; Dong, Y. W. Synthesis

And

Characterization

of

Highly-Ordered

ZnO/PbS

Core/Shell

Heterostructures. Superlattices Microstruct. 2011, 50 (5), 549-556, DOI: 10.1016/j.spmi.2011.08.017. (48) Zhu, H.; Shen, Y.; Wang, Q.; Chen, K.; Wang, X.; Zhang, G.; Yang, J.; Guo, Y.; Bai, R. Highly Promoted Removal of Hg(II) With Magnetic CoFe2O4@SiO2 Core–Shell Nanoparticles Modified By Thiol Groups. RSC Adv. 2017, 7 (62), 39204-39215, DOI: 10.1039/C7RA06163C. (49) Han, B.; Zhang, E.; Cheng, G.; Zhang, L.; Wang, D.; Wang, X. Hydrothermal Carbon Superstructures Enriched with Carboxyl Groups for Highly Efficient Uranium

Removal.

Chem.

Eng.

J.

2018,

10.1016/j.cej.2018.01.089. 27


338,

734-744,

DOI:


Page 28 of 41

(50) Wang, H.; Liu, Y.; Ifthikar, J.; Shi, L.; Khan, A.; Chen, Z.; Chen, Z. Towards A Better Understanding on Mercury Adsorption by Magnetic Bio-Adsorbents with γ-Fe2O3 From Pinewood Sawdust Derived Hydrochar: Influence of Atmosphere in Heat

Treatment.

Bioresour.

Technol.

2018,

256,

269-276,

DOI:

10.1016/j.biortech.2018.02.019. (51) Vikrant, K.; Kim, K.-H. Nanomaterials for the Adsorptive Treatment of Hg(II) Ions

from

Water.

Chem.

Eng.

J.

2019,

358,

264-282,

DOI:

10.1016/j.cej.2018.10.022. (52) Khan, A.; Szulejko, J. E.; Kim, K.-H.; Sammadar, P.; Lee, S. S.; Yang, X.; Ok, Y. S. A Comparison of Figure Of Merit (FOM) for Various Materials in Adsorptive Removal of Benzene under Ambient Temperature and Pressure. Environ. Res. 2019, 168, 96-108, 10.1016/j.envres.2018.09.019. (53) Szulejko, J. E.; Kim, K.-H.; Parise, J. Seeking the Most Powerful and Practical Real-World Sorbents for Gaseous Benzene as A Representative Volatile Organic Compound Based on Performance Metrics. Sep. Purif. Technol. 2019, 212, 980-985, DOI: 10.1016/j.seppur.2018.11.001. (54) Na, C.-J.; Yoo, M.-J.; Tsang, D. C. W.; Kim, H. W.; Kim, K.-H. High-Performance Materials for Effective Sorptive Removal of Formaldehyde in Air. J. Hazard. Mater. 2019, 366, 452-465, DOI: 10.1016/j.jhazmat.2018.12.011. (55) Ge, J. L.; Xiao, J. D.; Liu, L. L.; Qiu, L. G.; Jiang, X. Facile Microwave-Assisted Production of Fe3O4 Decorated Porous Melamine-Based Covalent Organic Framework for Highly Selective Removal of Hg2+. J. Porous Mater. 2016, 23 (3), 28


Page 29 of 41 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


791-800, DOI: 10.1007/s10934-016-0134-y. (56) Hutson, N. D.; Attwood, B. C.; Scheckel, K. G. XAS and XPS Characterization of Mercury Binding on Brominated Activated Carbon. Environ. Sci. Technol. 2007, 41 (5), 1747-1752, DOI: 10.1021/es062121q. (57) Vikrant, K.; Kumar, V.; Kim, K. H.; Kukkar, D. Metal-Organic Frameworks (MOFs): Potential and Challenges for Capture and Abatement of Ammonia. J Mater. Chem. A 2017, 5 (44), 22877-22896, DOI: 10.1039/C7TA07847A.

29



Page 30 of 41

NH2 Lawesson reagent

NH2

H 2N NH2

Fe3O4@SiO2-NH2

magnetic amide linked organic polymers

H N

O Cl

O

O

Cl Cl

NH2

HN

NH

S

NH

S

NH

O H 2N

sulfur-functionalized magnetic amide linked organic polymers

HN

O

S

O

NH

NH

Scheme 1. The synthesis procedure for S-MAOPs.

30


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Figure 1 The FT-IR spectra of different samples (a) and the N2 adsorption-desorption isotherms of MAOP and S-MAOP (b).

31



Fig. 2 TEM images of MAOP (a) and S-MAOP (b), and element mapping images of S-MAOP (c).

32


Page 32 of 41

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Fig. 3 Thermogravimetric curves of MNPs, MAOP and S-MAOP.

33



Fig. 4 VSM magnetization curves of MNPs, MAOP and S-MAOP; the insets show the digital images of S-MAOP solution before (left) and after (right) magnetic separation.

34


Page 34 of 41

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Fig. 5 The influence of pH on the adsorption with different samples. Conditions: adsorption dosage: 0.5 g L-1; C0=40 mg L-1; t=60 min; T=25 oC.

35



Fig. 6 Selectivity of S-MAOP for Hg2+. Conditions: adsorption dosage: 0.5 g L-1; each ion of 10 mg L-1; pH=3; t=60 min; T=25 oC.

36


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Fig. 7 Adsorption curve of Hg2+ (a) versus incubate time by S-MAOP along with the pseudo-second order kinetic plot (b). Conditions: adsorption dosage: 0.5 g L-1; C0=50 mg L-1; pH=3; T=25 oC.

37



Fig. 8 Adsorption curve of Hg2+ (a) with S-MAOP at different initial concentrations, along with the linear regression by fitting the equilibrium adsorption data with Langmuir adsorption model for Hg2+ (b). Conditions: adsorption dosage: 0.5 g L-1; pH=3; t=60 min; T=25 oC.

38


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Fig. 9 Adsorption capacity of S-MAOP for Hg2+ after several adsorption-desorption cycles.

39



Page 40 of 41

Table 1 Comparison the data of different adsorbents for Hg(II) removal. Partiti Maxi Equilib

K2

Initical concentr

time

ation (mg L-1)

coeffic

mum efficie

ient

ncy

(mg

(%)

g−1

Re ion

ity

(mg L-1)

)

Solut Capac

ation

min-1 (min)

val concentr

mg-1

Adsorbents

on

Final

(g rium

Remo

f. pH

(mg g-1) µM−1)

PAF-SH

7

8.13

10

0.4×

2.03× 99.99

1014

6.8

21

105

10-3

1.47× TAPB-BMTT 5

6.31

10

0.01

99.9

104

734

7.0

24

8.96

0.22

97.54

91.8

101.2

7.0

55

100

2.4

97.6

61.3

735.3

5.0

22

5

1×10-3

99.99

1216

7.0

17

703

3.0

23

PA-COF Fe3O4/M-COF

2.3 80 ×10-3

s

1.7× PTMT

180 10-4 10.7

POP-SH

10

4.86× 105

6 0.04 MOP-SH

20

2.81× 50

1.1×10-3

99.9 103

5

Th 28.9 S-MAOP

2

2.05× 50

0.8×10-3

99.99 104

7

is 512

3.0 wo rk

40


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Sulphur-doped magnetic amide linked organic polymer with good adsorption performance for Hg(II) ions was prepared by a facile and efficient strategy. 99x75mm (300 x 300 DPI)


Facile Approach To Prepare Sulfur-Functionalized Magnetic Amide

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