Adsorption behavior of heavy metal ions on a polymer-immobilized amphoteric biosorbent: Surface interaction...

Here we unveiled a novel magnetically separable amphoteric biosorbent (PD-Fe₃O₄@CCS) and investigated its adsorption behavior toward two classes of heavy metals, hexavalent chromium (Cr(VI)) and copper (Cu(II)) ions from water. Results indicated that the adsorption behavior of PD-Fe₃O₄@CCS for Cr(VI) was well described by Langmuir model; while for Cu(II) adsorption, the Freundlich model was the better one. Based on the kinetic results, both Cr(VI) and Cu(II) adsorption on PD-Fe₃O₄@CCS fitted well with the pseudo-second-order kinetic model. To evaluate the reusability and stability of PD-Fe₃O₄@CCS, regeneration tests were carried out for five cycles. Furthermore, the applicable feasibility of PD-Fe₃O₄@CCS in the real water matrix (including the single and binary pollutant systems) was studied, and results suggested the promising potential of PD-Fe₃O₄@CCS for large-scale application. Apart from these, the surface interactions between PD-Fe₃O₄@CCS and heavy metal ions in single and binary systems were systematically investigated based on FTIR and XPS analyses, which provided an essential implication for comprehending the interactions between biosorbents and contaminants in wastewater.