Utilizing synergistic effects of bifunctional polymer hydrogel PAM-PAMPS for selective capture of Pb(II) from wastewater

The preparation of hydrogel adsorbents with admirable performance for efficient selective remove Pb(II) in complex wastewater still remains a great challenge. Herein, a novel bifunctional modified polymer hydrogel PAM-PAMPS was prepared by crosslinking acrylamide (AM) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS). Compared with PEG, PAA and PAMPS, PAM-PAMPS exhibited both the maximum adsorption capacity of Pb(II) (541.90 mg/g) and satisfactory selectivity for Pb(II) in multiple heavy metal ions coexistence solutions. Various characterizations indicated that SO3H and NH2 as active sites on PAM-PAMPS occur the synergistic effects of ion-exchange and coordination with Pb(II) during the adsorption process, respectively. The adsorption energy Ead(PAM-PAMPS) obtained from density functional theory (DFT) calculations was lower than the other three hydrogels, manifesting that PAM-PAMPS formed the most stable complex with Pb(II), which further demonstrated that Pb(II) preferred to combine with PAM-PAMPS to selective capture of Pb(II). The practice utilization of PAM-PAMPS was assessed by wastewater of electroplate containing Pb(II). Meanwhile, the removal ratio of PAM-PAMPS was maintained at about 89% after 4 adsorption-desorption cycles. This study establishes a new and effective idea for the design and fabrication of bifunctionalized modified polymer hydrogels. A novel bifunctional polymer hydrogel PAM-PAMPS was synthesized by free radical polymerization that exploited the synergistic effect to promote a satisfactory selectivity for Pb(II). This study demonstrates the design strategy of bifunctional polymer hydrogels and enlightens for the selective capture of Pb(II) from wastewater. [Display omitted]