Adsorption Performance and Mechanism of Capsaicin-Containing Polymer Materials with Functional Structure on Harmful Hexavalent Chromium

Capsaicin-containing polymer materials with functional structure were successfully prepared by simple free radical polymerization of capsaicin functional monomers (Poly(AMTHBA-co-NVP)) with 1-vinyl-2-pyrrolidone. Compared with pure capsaicin polymer, the adsorption content of the obtained Poly(AMTHBA-co-NVP) increased by more than 3 times, which has huge potential research value. The composition and morphology of Poly(AMTHBA-co-NVP) before and after adsorption were analyzed using XRD, FT-IR, XPS, SEM and TEM. The mechanism of the adsorption process was summarized, through the study of the optimal molar ratio of reactants, acid-base environment, adsorption model fitting, characterization data results, and pollutant competition experiments. The following conclusions can be drawn: 1) The pseudo-second-order kinetic model better matches the adsorption kinetics of partial Cr(VI). 2) Part of the restored Cr(III) is trapped by specific groups on Poly(AMTHBA-co-NVP) and part of the Cr(III) is released back into solution. 3) The adsorption mechanism includes ion exchange, coordination and chemical bonding. 4) The highest adsorption capacity of the polymeric material was up to 370.59 mg/g when the molar ratio of reactants was AMTHBA:NVP=2:8. This work not only provides ideas for the synthesis of capsaicin structural and functional polymers, but also provides inspiration for wastewater treatment measures.