Selective Removal Of Hg Research Articles

Preparation of Macroporous Double-Network MoS2-Based Beads for Efficient and Selective Removal of Hg(II) from Water

Preparation of Macroporous Double-Network MoS₂-Based Beads for Efficient and Selective Removal of Hg(II) from Water

Aminothiol supported dialdehyde cellulose for efficient and selective removal of Hg(II) from aquatic solutions

The increasingly serious problem of mercury pollution has caused wide concern, and exploring adsorbent materials with high adsorption capacity is a simple and effective approach to address this concern. In the recent study, dialdehyde cellulose (DAC), cyanoacetohydrazide (CAH), and carbon disulfide (CS2) are used as raw materials for the (DAC@CAH@SK2) preparation material through the three-steps method. By utilizing the following characterization techniques; thermogravimetric analysis (TGA), N2 adsorption–desorption isotherm (BET), elemental analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD), 1HNMR and Energy Dispersive X-ray Spectroscopy (EDS) of DAC@CAH@SK2 composite. The point of zero charge (pHPZC) for the prepared DAC@CAH@SK2 also was examined. From the batch experiments, the optimum conditions were found to be pH (5–8), an Hg2+ concentration of 150 mg/L, a DAC@CAH@SK2 dose of 0.01 g, and a contact time of 180 min with a maximum adsorption quantity of 139.6 mg/g. The process of Hg2+ adsorption on the DAC@CAH@SK2 material was spontaneous exothermic, monolayer chemisorption, and well-fitted to Langmuir and pseudo-2nd-order models. The DAC@CAH@SK2 selectivity towards the Hg2+ was examined by investigating the interfering metal ions effect. The DAC@CAH@SK2 was successfully applied for the Hg2+ removal from synthetic effluents and real wastewater samples with a recovery % exceeding 95%. The prepared DAC@CAH@SK2 was regenerated using a mixture of EDTA and thiourea. Also, FT-IR analysis indicates that the synergistic complexation of N and S atoms on DAC@CAH@SK2 with Hg(II) is an essential factor leading to the high adsorption capacity.

Efficient and Selective Removal of Hg(II) from Aqueous Solution by a Highly Stable Amino Isonicotinic-Based Coordination Polymer

Efficient and Selective Removal of Hg(II) from Aqueous Solution by a Highly Stable Amino Isonicotinic-Based Coordination Polymer

High-efficiency and selective removal of Hg(Ⅱ) and Pb(Ⅱ) ions from aquatic system by 1T/2H mixed-phase MoSe2 nanoflowers: Performance and mechanism

High-efficiency and selective removal of heavy metal ions from aquatic system is urgently needed and remains a major challenge. Endowed with rich Se atoms and unique 2D structure, MoSe2 should be promising for the removal of heavy metal ions. However, it remains challenging to balance the efficient exposure of active sites and the stability of materials, and the potential mechanism of the interactions between heavy metal ions and the interface of MoSe2 with different crystal phases and structures has yet to be comprehensively explored. Herein, mixed-phase 1T/2H MoSe2 nanoflowers featured with ultrathin nanosheets, high ratio of 1T phase, enlarged interlayer spacing, and defect-rich structure have been synthesized and demonstrated excellent performance for removing Hg(II) and Pb(II) ions from aquatic system, including high capacity (952.4 mg·g−1 for Hg(II); 217.9 mg·g−1 for Pb(II)), rapid kinetics, superior selectivity, and anti-interference ability. The ultrathin nanosheets and enlarged interlayer spacing ensured efficient exposure of Se atoms; the high ratio of 1T phase was beneficial for the binding of heavy metal ions (as confirmed by DFT calculations). The defect-rich structure not only provided additional channels for ions diffusion, but also produced more active sites for ion binding and charge transfer. Benefiting from these structural characteristics, 1T/2H MoSe2 could effectively and selectively remove Hg(II) and Pb(II) ions under the coexistence of various cations in practical water environment, the corresponding separation factors were greater than 170. Moreover, the interaction mechanism between two target ions and MoSe2 was elucidated byexperimentandDFT calculation. The present work not only explored advanced materials for the purification of heavy metal ions polluted water, but also may promote the exploration of MoSe2 in environmental remediation.

Rapid and Selective Removal of Hg2+ by Copper Sulfides under Strongly Acidic Conditions: Mechanism, Kinetics, and Its Application in Recovering Hg from Waste Acids of Smelters

In this study, CuSx/TiO2 was developed to selectively remove Hg2+ from waste acids. X-ray photoelectron spectroscopy and X-ray diffraction analyses demonstrated that there were two reaction routes for Hg2+ removal by CuSx/TiO2, corresponding to the two types of copper sulfides (i.e., CuS and Cu2S). The CuS route with the product HgS occurred regardless of the presence of Cl–, while the Cu2S route with the product Hg2Cl2 only occurred with Cl–. Therefore, Cl– exhibited a remarkable promotion on Hg2+ removal. Kinetic analysis demonstrated that the CuS route was markedly faster than the Cu2S route, which accounted for the rapid removal of Hg2+. CuSx/TiO2 showed excellent performance for Hg2+ removal at pH 2.0 with an adsorption rate of 16.3 mg g–1 min–1, and removed Hg2+ can be recovered as liquid Hg0 as a co-benefit of Hg0 recovery units in smelters. Therefore, CuSx/TiO2 was a promising sorbent for Hg2+ recovery in waste acids for centralized control.

Pyridine-based covalent organic framework for efficient and selective removal of Hg(II) from water: Adsorption behavior and adsorption mechanism investigations

The high toxicity and carcinogenicity of mercury ions (Hg2+) motivates the development of efficient technologies for their removal from water. In this work, a pyridine-based covalent organic framework (Pyridine-COF) was synthesized via the Schiff base condensation reaction of 1,3,5-tris(4-aminophenyl)benzene (TAP) and 2,6-diformylpyridine (DFP) at room temperature. The obtained Pyridine-COF was crystalline, microporous and possessed a high specific surface area (348.5 m2 g−1). The close association of the pyridine linker and imine groups in the COF structure created an N-rich pore space that showed high selectivity towards Hg2+ ions. Adsorption experiments showed Pyridine-COF to have very fast Hg2+ adsorption kinetics, a high adsorption capacity for Hg2+ (719.4 mg g−1 at 293 K, 840.3 mg g−1 at 303 K, and 1000 mg g−1 at 313 K), and very good Hg2+ removal performance in the presence of other metal cations. Further, Pyridine-COF maintained a high adsorption capacity over five cycles of adsorption–desorption, confirming good reusability as an adsorbent. Mechanistic studies using X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations revealed that the adsorption of Hg2+ in the pores of Pyridine-COF was mainly chelation not covalent interactions. Pyridine-COF represents one of the best COF-based adsorbents developed to date for the removal of Hg2+ from water.

Selective removal of Hg(II) by UiO-66-NH2 modified by 4-quinolinecarboxaldehyde: from experiment to mechanism.

In wastewater, heavy metal Hg causes serious harm to ecology, so it needs to be removed. In this paper, a novel MOF adsorbent (UiO-66-QU) was prepared by modifying UiO-66-NH2 with 4-quinolinecarboxaldehyde, which was used to selectively remove Hg(II) from water. The adsorbent was characterized using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), zeta potentiometer, and X-ray photoelectron spectroscopy (XPS). In order to investigate the Hg(II) adsorption performance of UiO-66-QU, the effect of time, initial concentration, pH, and temperature were carried out. Langmuir model fitting shows that the maximum adsorption capacity of UiO-66-QU for Hg(II) is 556mg/g at 298K. The experimental results show that UiO-66-QU has better Hg(II) adsorption capacity than UiO-66-NH2. The isotherm is in accordance with pseudo-second-order models. It is indicated that the adsorption process is mainly monolayer chemical adsorption. The thermodynamic parameters also indicate that the adsorption process is spontaneous and endothermic. It has excellent reusability and selectivity. XPS and the zeta potential showed that the adsorption mechanism was the complex reaction of Hg(II) with nitrogenous group. Therefore, the adsorbent has potential application prospects in removal of Hg(II) from wastewater.

Selective removal of Hg2+ from acidic wastewaters using sulfureted Fe2TiO5: Underlying mechanism and its application as a regenerable sorbent for recovering Hg from waste acids of smelters

The selective removal of Hg2+ from waste acids containing high concentrations of other metal cations, such as Cu2+, Zn2+, and Cd2+, which are discharged from nonferrous metal smelting industries, is in great demand. Herein, sulfureted Fe2TiO5 was developed as a regenerable magnetic sorbent to recover Hg2+ from waste acids for centralized control. Sulfureted Fe2TiO5 exhibited an excellent ability for Hg2+ removal with the capacity of 292–317 mg g−1 and the rate of 49.5–57.6 mg g−1 h−1 at pH=2–4. Meanwhile, it exhibited an excellent selectivity for Hg2+ removal that not only the coexisting Cu2+, Zn2+, and Cd2+ can scarcely be adsorbed but also Hg2+ adsorption was hardly inhibited. The mechanism and kinetic studies indicated that the Fe2+ in the FeS2 coated on sulfureted Fe2TiO5 was exchanged with Hg2+ adsorbed at a Fe2+ to Hg2+ mole ratio of 1:2. Meanwhile, most of the Hg2+ removed by sulfureted Fe2TiO5 can be thermally desorbed primarily as ultra-high concentrations of gaseous Hg0, which can finally be recovered as liquid Hg0 for centralized control in combination with existing Hg0-recovery devices in smelters. Moreover, the spent sulfureted Fe2TiO5 could be regenerated for duty-cycle operations with re-sulfuration without a remarkable degradation of the Hg2+-removal performance. Therefore, Hg2+ recovery using sulfureted Fe2TiO5 may be a promising, low-cost, and environmentally friendly technology for the centralized control of Hg2+ in waste acids discharged from smelters.

Post-functionalized metal−organic framework for effective and selective removal of Hg(II) in aqueous media

For the serious hazards to human and natural environment caused by the toxic Hg(II), a new MOF-based adsorption material, UiO-66-AHMT, was designed and synthesized by incorporating the 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole molecule into the UiO-66-NH2 matrix and used for the removal of Hg(II) from aqueous media. As expected, UiO-66-AHMT exhibits rapid removal ability toward Hg(II) and maximum uptake capacity of 327.88 mg/g at 298 K and pH = 5, the adsorption capacity is improved significantly compared to the unmodified UiO-66-NH2 and comparable in the excellent UiO-66 based adsorbents reported so far. The adsorption behaviors of UiO-66-AHMT conform well to the pseudo-second-order and Langmuir models, respectively, which indicate that the adsorption process is mainly monolayer chemisorption. Meanwhile, UiO-66-AHMT shows strong selectivity to Hg(II) in the coexistence of varieties of metal ions and outstanding recyclability characteristics. To investigate the adsorption mechanism, the Hg(II) loaded UiO-66-AHMT mainly analyzed by XPS suggests that the nitrogen- and sulfur-containing groups in grafted molecule have the synergistic complexation to Hg(II). Furthermore, the binding strength between different function sites and Hg(II) are quantified and the stable complexation patterns are obtained based on the DFT calculation. These results strongly confirm that UiO-66-AHMT is a potential adsorbent in the practical treatment of wastewater containing Hg(II).

Microwave-assisted functionalization of PAN fiber by 2-amino-5-mercapto-1,3,4-thiadiazol with high efficacy for improved and selective removal of Hg2+ from water

Mercury (Hg2+) contamination in water is associated with potential toxicity to human health and ecosystems. Many research studies have been ongoing to develop new materials for the remediation of Hg2+ pollution in water. In this study, a novel thiol- and amino-containing fibrous adsorbent was prepared by grafting 2-amino-5-mercapto-1,3,4-thiadiazol (AMTD) onto PAN fiber through a microwave-assisted method. The synthesized functional fiber was characterized by FTIR, SEM, and elemental analysis. Adsorption tests depicted that for mercury uptake, PANMW-AMTD fiber exhibited enhanced adsorption capacity compared with other fibrous adsorbents and selective adsorption feature under the interference of other metal ions, including Pb2+, Cu2+, Cd2+, and Zn2+. The influence of pH on the adsorption process was investigated and the effect of temperature revealed that the adsorption sorption process was endothermic and the adsorption performance of PANMW-AMTD was elevated with the increase of temperature. Kinetic studies of PANMW-AMTD fiber followed the pseudo-second-order and the adsorption isotherm of Hg2+ was well fitted by Sips and Langmuir equations, given the maximum adsorption amount of 332.9 mg/g. XPS results suggested that a synergetic coordination effect of sulfur and nitrogen in functional fiber with mercury took responsibility for the adsorption mechanism in the uptake process. In addition, the prepared PANMW-AMTD fiber could easily be regenerated with 0.1 M HCl for five times without significant reduction of mercury removal efficiency. Thus, this study will facilitate the research on novel functional material for the removal of mercury from water.

Selective Removal of Hg2+ Ions from Water Using New Functionalized Silica Resin: Equilibrium, Thermodynamics and Kinetic Modeling Studies

In current study, the diphenylaminomethylcalix[4]arene (3) was synthesized and immobilized onto silica surface to prepare a selective, regenerable and stable resin-4. The synthesized resin-4 has been characterized by FT-IR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX) and Brunauer-Emmett-Teller (BET) techniques. To check the adsorption capacity of resin-4, the batch and column adsorption methodology were applied and it has observed that the resin-4 was selectively removed Hg2+ ions under the optimized parameters. The maximum adsorption capacity was obtained at pH 9 using 25 mg/L of resin-4. Under the optimal conditions, different equilibrium, kinetic and thermodynamic models were applied to experimental data. The results show that adsorption mechanism is chemical in nature following Langmuir model with good correlation coefficient (R2=0.999) and having 712.098 (mmol/g) adsorption capacity. The energy of calculated from D-R model suggests the ion exchange nature of the adsorption phenomenon. Dynamic adsorption experiments were conducted using Thomas model. The maximum solid phase concentration (qo) was 7.5 and rate constant was found to be 0.176 with (R2=0.938) for Hg2+ ions. The kinetic study describes that the adsorption mechanism follows pseudo second order (R2=0.999). The thermodynamic parameters such as ∆H (0.032 KJ/mol) and ∆S (0.127 KJ/mol /K) and ∆G (-5.747,-6.306, -7.027 KJ/mol) shows that the adsorption of Hg2+ ion is endothermic and spontaneous. The reusability of resin-4 was also checked and it has observed that the after 15 cycle only 1.2 % adsorption reduces. Moreover, the resin-4 was applied on real wastewater samples obtained from local industrial zone of Karachi, Sindh-Pakistan.

Selective Removal of Hg2+ Ions from Water Using New Functionalized Silica Resin: Equilibrium, Thermodynamics and Kinetic Modeling Studies

In current study, the diphenylaminomethylcalix[4]arene (3) was synthesized and immobilized onto silica surface to prepare a selective, regenerable and stable resin-4. The synthesized resin-4 has been characterized by FT-IR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX) and Brunauer-Emmett-Teller (BET) techniques. To check the adsorption capacity of resin-4, the batch and column adsorption methodology were applied and it has observed that the resin-4 was selectively removed Hg2+ ions under the optimized parameters. The maximum adsorption capacity was obtained at pH 9 using 25 mg/L of resin-4. Under the optimal conditions, different equilibrium, kinetic and thermodynamic models were applied to experimental data. The results show that adsorption mechanism is chemical in nature following Langmuir model with good correlation coefficient (R2=0.999) and having 712.098 (mmol/g) adsorption capacity. The energy of calculated from D-R model suggests the ion exchange nature of the adsorption phenomenon. Dynamic adsorption experiments were conducted using Thomas model. The maximum solid phase concentration (qo) was 7.5 and rate constant was found to be 0.176 with (R2=0.938) for Hg2+ ions. The kinetic study describes that the adsorption mechanism follows pseudo second order (R2=0.999). The thermodynamic parameters such as ∆H (0.032 KJ/mol) and ∆S (0.127 KJ/mol /K) and ∆G (-5.747,-6.306, -7.027 KJ/mol) shows that the adsorption of Hg2+ ion is endothermic and spontaneous. The reusability of resin-4 was also checked and it has observed that the after 15 cycle only 1.2 % adsorption reduces. Moreover, the resin-4 was applied on real wastewater samples obtained from local industrial zone of Karachi, Sindh-Pakistan.

Synthesis of coordination polymer by 2,2′-dithiodipropionic acid and selective removal of Hg(ii)/Pb(ii) in wastewater

At present, the functionalized Zr-based coordination polymer for heavy metal ions removal are primarily implemented via post-synthesis, and it is still a challenge to reduce the concentration of heavy metal ions to wastewater discharge standard. In this work, the 2,2′-dithiodipropionic acid modified Zr-based coordination polymer (named as Zr-DTDPA) was prepared by direct synthesis. It presented extraordinary adsorption ability in the process of removing Hg(II)/Pb(II). The optimum pH for Hg(II) and Pb(II) absorption was 4.0 and 6.0, respectively, and the saturated adsorption capacity reached 960 mg/g and 478 mg/g. The adsorption process can be exceedingly fitted by Langmuir isotherm model and pseudo-second-order (PSO) kinetic model, which indicated that chemisorption played a dominant role. Additionally, the maximum selectivity coefficient reached 21.36 × 105 and 5605 for Hg(II) and Pb(II). Impressively, the residual contents of Hg(II) and Pb(II) were only 1.04 μg/L and 0.34 mg/L, which respectively reached the concentration standard of Hg(II) and Pb(II) in wastewater. Zr-DTDPA was easy to be regenerated, and the removal rate of Hg(II) had only decreased by 17.15% after ten consecutive cycles. The results of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) suggested that the adsorption performance of Zr-DTDPA toward Hg(II)/Pb(II) was primarily determined by thiol/thio groups, and the adsorption mechanism was the interaction between sulfur atoms and Hg(II)/Pb(II) ions.

Preparation of Micro-Nano Material Composed of Oyster Shell/Fe3O4 Nanoparticles/Humic Acid and Its Application in Selective Removal of Hg(II).

Micro-nano composite material was prepared to adsorb Hg(II) ions via the co-precipitation method. Oyster shell (OS), Fe3O4 nanoparticles, and humic acid (HA) were used as the raw materials. The adhesion of nanoparticles to OS displayed by scanning electron microscopy (SEM), the appearance of the (311) plane of standard Fe3O4 derived from X-ray diffraction (XRD), and the transformation of pore sizes to 50 nm and 20 μm by mercury intrusion porosimetry (MIP) jointly revealed the successful grafting of HA-functionalized Fe3O4 onto the oyster shell surface. The vibrating sample magnetometer (VSM) results showed superparamagnetic properties of the novel adsorbent. The adsorption mechanism was investigated based on X-ray photoelectron spectroscopy (XPS) techniques, which showed the process of physicochemical adsorption while mercury was adsorbed as Hg(II). The effects of pH (3–7), initial solution concentration (2.5–30 mg·L−1), and contact time (0–5 h) on the adsorption of Hg(II) ions were studied in detail. The experimental data were well fitted to the Langmuir isotherm equation (R2 = 0.991) and were shown to follow a pseudo-second-order reaction model (R2 = 0.998). The maximum adsorption capacity of Hg(II) was shown to be 141.57 mg·g−1. In addition, this new adsorbent exhibited excellent selectivity.

Rapid and selective removal of Hg(II) ions and high catalytic performance of the spent adsorbent based on functionalized mesoporous silica/poly(m-aminothiophenol) nanocomposite

The toxic Hg(II) being released excessively into the water body from various sources has threatened the environment and human health. The aim of this study is to design a rapid and selective adsorbent, and propose an alternative way to dispose the spent adsorbent. To this end, a new material (MAP) was designed by inducing the polymerization of m-aminothiophenol onto MCM-41 (Mobil Composition of Matter) surface obtained using cheap diatomite as a silica source and modified by APTES ((3-aminopropyl) triethoxysilane), and the spent adsorbent was further converted into an active catalyst for acetophenone synthesis. The adsorption properties of the MAP were systematically explored under different parameters, and the corresponding results were analyzed based on different adsorption kinetic and isotherm models. The study found the removal rate and adsorption capacity of the MAP could reach 96.56% and 242.42mg/g within 15min. The coexisting cations showed little competition effect on the removal of Hg(II), and the adsorption capacities after five cycles did not obviously decrease. Kinetic study indicated that the adsorption data were well fitted to the pseudo-second-order model, and the adsorption equilibrium data followed the Langmuir model. After adsorption studies, the Hg(II)-MAP was used as a catalyst in the reaction of phenylacetylene to acetophenone with high yield of 97.01%. This work not only provides a rapid and selective adsorbent for removal of Hg(II) ions, but also opens a novel avenue for reusing the toxic spent adsorbent for catalytic application.

BODIPY-Derived Polymeric Chemosensor Appended with Thiosemicarbazone Units for the Simultaneous Detection and Separation of Hg(II) Ions in Pure Aqueous Media.

Developing a simple and cheap analytical method for the selective detection and quantitative separation of toxic ions present in aqueous media is the biggest challenge faced by the chemosensing research community. Here, a 5,5-difluoro-1,3,7,9-tetramethyl-10-phenyl-5 H-dipyrrolo-diazaborinine-derived water-soluble polymer integrated with thiosemicarbazone units was rationally designed and synthesized for the simultaneous detection and separation of Hg(II) ions in pure aqueous solution. The water-soluble polymer scaffold poly( N, N'-dimethyl acrylamide- co-5,5-difluoro-1,3,7,9-tetramethyl-10-phenyl-5 H-dipyrrolo-diazaborinine-2-carbaldehyde) was synthesized by reversible addition-fragmentation chain transfer polymerization, followed by post-polymerization modification with thiosemicarbazide, leading to the formation of the target probe, P1. The nonemitting P1 exhibited bright yellow emission upon exposure to Hg(II) ions, with a limit of detection as low as 0.37 μM. This turn-on emission behavior triggered by Hg(II) ions might originate from the suppression of isomerization around the C═N bond of the thiosemicarbazone moiety caused by the formation of a coordination complex between P1 and Hg(II) ions. In addition, P1 displayed excellent selectivity toward Hg(II) ions over other metal cations. Finally, the selective removal of Hg(II) ions from an aqueous solution containing various metal ions was achieved by precipitation, which is probably caused by the fact that coordination complexes whereby Hg(II) ions acted as bridgeheads between P1 molecules had formed.

Thiol-Functionalized Pores via Post-Synthesis Modification in a Metal-Organic Framework with Selective Removal of Hg(II) in Water.

Owing to the rapid increase of Hg(II) ions in water resources, the design and development of new adsorbents for Hg(II) removal are becoming a significant challenge in environmental protection. Herein, a thiol-functionalized metal-organic framework (SH-MiL-68(In)) was successfully prepared through a post-synthesis modification procedure, and the framework intactness and porosity were well maintained after this process. SH-MiL-68(In) exhibited selective adsorption performance for Hg(II) ions in water. Meanwhile, SH-MiL-68(In) also shows a high adsorption capacity (450 mg g-1), large adsorption rate (rate constant k2 = 1.25 g mg-1 min-1), and good recycling of adsorption capacity toward Hg(II) ions. The excellent adsorption performance resulted from the strong binding interactions between -SH soft basic groups and Hg(II) soft acidic ions.

Post-functionalization of UiO-66-NH2 by 2,5-Dimercapto-1,3,4-thiadiazole for the high efficient removal of Hg(II) in water.

A new MOFs adsorbent was prepared by post-functionalization of UiO-66-NH2 with 2,5-Dimercapto-1,3,4-thiadiazole and utilized to remove the Hg(II) in water selectively. The UiO-66-types were detected by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), Brunauer-Emmett-Teller (BET) and zeta potential instruments. The adsorption properties of the new MOFs adsorbent were investigated by batch experiments. The actual maximum adsorption amount was 670.5 mg/g at the optimal pH of 3. Adsorption kinetic and isotherm models were exceedingly fitted to pseudo-second-order and Langmuir/Dubinin-Radushkevich, respectively. The adsorption process and mode were geared to monolayer and chemisorption, the removal rate was directly proportional to the square of mercury ions concentration. The UiO-66-DMTD adsorbent was easy to be regenerated and the removal rate decreased by only 13.5% after ten consecutive cycles. The results of FTIR, XRD and XPS suggested that the adsorption mechanism lay on the complexation reaction between Hg(II) and thiol/nitrogen-containing groups. Moreover, compared with other competitive metal ions, viz., Zn(II), Co(IV), Ni(II), Cd(II), Mg(II), Fe(III), Ca(II) and Cu(II), the UiO-66-DMTD demonstrated an outstanding selective adsorption for Hg(II). These results manifested that the UiO-66-DMTD was a latent adsorbent for the efficient and selective removal of Hg(II) in wastewater.

Surface-Tailored Nanocellulose Aerogels with Thiol-Functional Moieties for Highly Efficient and Selective Removal of Hg(II) Ions from Water

Developing an easily recyclable and reusable biosorbent for highly efficient removal of very toxic Hg(II) ions from bodies of water is of special significance. Herein, a thiol-functionalized nanocellulose aerogel-type adsorbent for the highly efficient capture of Hg(II) ions was fabricated through a facile freeze-drying of bamboo-derived 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized nanofibrillated cellulose (TO-NFC) suspension in the presence of hydrolyzed 3-mercaptopropyl-trimethoxysilane (MPTs) sols. Notably, the modified aerogel was able to effectively and selectively remove more than 92% Hg(II) ions even in a wide range of Hg(II) concentrations (0.01–85 mg/L) or coexistence with other heavy metals. Besides, the adsorption capacity of the aerogel was not compromised much by the variation in pH values of Hg(II) solutions over a wide pH range. The fitting results of adsorption models suggested the monolayer adsorption and chemisorptive characteristics with the maximal uptake capacity as high as ...

Microwave Assisted Preparation of Thio-Functionalized Polyacrylonitrile Fiber for the Selective and Enhanced Adsorption of Mercury and Cadmium from Water

In order to overcome the drawbacks of conventional heating for performing surface modification process, such as long synthesis time, low ef ciency, and adsorption capacity, we reported a novel approach by introducing a microwave (MW) assisted method to prepare a thio-functionalized fibrous adsorbent (PANMW-Thio) for the enhanced and selective removal of Hg2+ and Cd2+ from water in this study. The properties and morphologies of the adsorbent prepared by the MW-assisted method and conventional heating were compared through FTIR, XRD, SEM characterization, and mechanical tests, and the results revealed that the MW assisted method is a satisfactory technology to enable a higher sulfur content and reinforced mechanical property for the adsorbent. The selective adsorption experiment indicated that PANMW-Thio fibers possess higher affinity toward both Hg2+ and Cd2+ in the mixed solution with Pb2+, Cu2+, Ni2+, and Zn2+. The optimum pH value for the adsorption of Hg2+ and Cd2+ was found to be 7 with maximum adsorp...