Microwave-assisted supramolecular double crosslinked chitosan-based molecularly imprinted polymer for synergistic recognition and selective recovery of Cd(II) and As(V) from water: Performance and mechanistic insights

A novel model of the sustainable double crosslinked molecularly imprinted polymer (D-Crosslinked MIP) represented as a supramolecular imprinted polymer was synthesized via the bulk polymerization method. The primary crosslinking was fabricated using biomacromolecule chitosan as a functional monomer and glutaraldehyde as a crosslinker. The primary crosslinked was subjected to dynamic interactions in a secondary crosslinking by binding Al₂O₃-NPs and TiO₂-NPs, forming the supramolecular D-Crosslinked-MIP. The dually crosslinked formed from combining three distinct crosslinkers in one system for the interaction with As(V) and Cd(II). A microwave was employed to evaluate the performance of the designed material in selectivity and extraction of metal ions from water. The FT-IR, XRD, TG/DTA, SEM-EDX, TEM, and XPS were used to verify the characteristics of (D-nano-Al₂O₃@Crosslinked Chitosan@D-nano-TiO₂). The type of solvents, selectivity, interferences, microwave-contact time, pH, temperatures, concentrations, and regeneration were investigated. By using the D-Crosslinked-MIP, at 15 s, Cd(II) revealed a recovery capacity of 99.03 %, Q_max 862.07 mg/g, while As(V) demonstrated a recovery capacity of 99.06 %, Q_max 850.75 mg/g. The D-Crosslinked-MIP exhibited BETs of 69.01 m²/g with a pore volume of 0.2340 cm³/g owing to polymeric crosslinking by metal oxide NPs. The kinetics, isotherm models, and mechanisms of dually crosslinking and extraction of toxic metals were discussed.