Investigation of removal of Pb(II) and Hg(II) by a novel cross-linked chitosan-poly(aspartic acid) chelating resin containing disulfide bond

A novel cross-linked chitosan-poly(aspartic acid) chelating resin was synthesized by combining chitosan and poly(aspartic acid) derivative with crosslinker. The structure and morphology of the resin containing disulfide bonds were characterized by 1 H NMR, FT-IR, Raman spectra, and SEM. Adsorption of Pb(II) and Hg(II) from aqueous solution by the resulted chelating resin was investigated in batch techniques. The result of the Raman spectra suggests that the disulfide bonds in the resin also play an important role in the adsorption of Pb(II) and Hg(II). The kinetic data were fitted to pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, which is suggestive of following closely the pseudo-second-order kinetic model. Equilibrium data were fitted to Langmuir, Freundlich, and D–R isotherm models. The results of equilibrium isotherm reveal that the empirical Langmuir equation provides an accurate description of the experimental data under the studied concentration range. In addition, thermodynamic and regeneration properties of the adsorbent were also studied.