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In this study, cross-linked chitosan microspheres (CCTS) was synthesized from chitosan and epichlorohydrin (ECH), then, 2-(chloromethyl) benzimidazole (CBM) was introduced to modify CCTS as the ligand. The resulting CBM-chitosan was characterized by EA, FTIR and TGA, and tested for metal adsorption. Results showed that CBM-chitosan has a relatively high selectivity toward Hg(2+). Equilibrium data were fitted well with Langmuir isotherms with the maximum adsorption capacity of 257.8 mg/g for Hg(2+). Both kinetics and thermodynamic parameters of the adsorption process were obtained. The data indicated that adsorption process was exothermic spontaneous reaction and kinetically proceeded according to Second-order kinetics model. CBM-chitosan can be eluted effectively using 1.0 mol/L HCl solution and it has a potential use for separation and preconcentration of Hg(2+) ions from contaminated natural waters., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

An organic polymeric resin was synthesized by anchoring p-aminobenzoic acid onto macroporous chloromethylated polystyrene beads, and was used for Zn(II) removal from aqueous solutions. The resin exhibited an initially rapid adsorption property for Zn(II) with equilibrium time of 10 h and the maximum adsorption capability approached 184.5 mg g−1. Optimum pH was 4.5. The mechanism of adsorption was investigated using kinetic, isotherm and thermodynamic models. The adsorption kinetic data were described well by a pseudo second-order model with R2 of 0.997. There was a negative Δ G (−17.98 kJ mol−1) and positive Δ H (13.58 kJ mol−1). HCl solution (1.0 mol l−1) could achieve an elution rate of 100%. The experimental data were well fitted by the Thomas model with R2 of 0.9826. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A novel chelating resin, polyacrylonitrile-2-amino-1,3,4-thiadiazole (PAN-ATD), was prepared via one-step reaction and its structure was characterized by elemental analysis and FT-IR. The adsorption properties of the resin for Hg(II) were investigated by batch and column experiments. Batch adsorption results showed that PAN-ATD had high affinity towards Hg(II) and the maximum adsorption capacity estimated from the Langmuir model was 526.9 mg/g at 308 K. The adsorption kinetic and equilibrium data were well fitted to the pseudo-second-order model and the Langmuir isotherm model, respectively. Furthermore, the resin can be easily regenerated and reused with less than 10% loss of adsorption capacity. Also, the resin and its metal complexes were studied by SEM, TGA, and energy dispersive X-ray spectroscopy (EDS). With good overall properties (a high selectivity adsorption capacity, easy to be regenerated and stable application capacity) PAN-ATD resin can not only be used in selective removal of Hg(II) from waste solution, but also be used for preparation of the separation and enrichment column applied in the analysis and detection area. [ABSTRACT FROM AUTHOR]

Highlights: [•] The chelating cross-linked chitosan (CBM-chitosan) is a novel adsorption material. [•] 2-(Chloromethyl) benzimidazole was first connected to cross-linked chitosan. [•] CBM-chitosan shows high selectivity and good adsorption capacity toward Hg2+. [•] CBM-chitosan can be eluted effectively and has satisfactory reusability. [•] CBM-chitosan is a potential biosorbent for Hg2+ analysis, removal and recovery. [ABSTRACT FROM AUTHOR]

A novel chelating resin, polyacrylonitrile-2-aminothiazole(PAN-AT), was synthesized simply by the reaction of polyacrylonitrilewith 2-aminothiazole. Optimization of the PAN-AT synthesis was carriedout at different temperatures, different molar ratios of reagents,and different time intervals in N,N-dimethylformamide (DMF) using response surface methodology (RSM)for the first attempt. The functional group capacity (the contentof the functional group) and the percentage conversion of the functionalgroup of PAN-AT prepared under the optimum conditions were 3.94 mmol/gand 41.10%, respectively. The structure of PAN-AT was characterizedby elemental analysis and FTIR. Meanwhile, the adsorption propertiesof the resin for Hg(II) were investigated by batch and column experiments.The results suggested that the resin possessed much better adsorptioncapability for Hg(II) than for other metal ions and the maximum saturatedadsorption capacity estimated from the Langmuir model was 454.9 mg/gat 308 K. Furthermore, the resin could be regenerated through thedesorption of the Hg(II) anions using 3.0 mol/L HNO3solutionand could be reused to adsorb again. Finally, the resin and its metalcomplexes were studied by SEM, TGA, and energy dispersive X-ray spectroscopy(EDS). Also, the PAN-AT chelating resin could provide a potentialapplication for a treatment process of Hg(II) contaminated wastewater. [ABSTRACT FROM AUTHOR]