Removal of Cr(VI) from aqueous solution using functionalized poly(GMA-co-EGDMA)-graft-poly(allylamine)

To remove Cr(VI) from aqueous solution, a macroporous poly glycidyl methacrylate-co- ethylene glycol dimethacrylate (poly(GMA-co-EGDMA)) adsorbent was synthesized by radical suspension copolymerization. Allylamine was used to open the epoxy ring of the prepared copolymer, then the radical polymerization of the grafted allylamine was performed, and as the last step, methyl isothiocyanate (MITC) was reacted with the crosslinked graft copolymers to introduce the thiourea groups. The introduced amine and thiourea functional groups enabled the effective removal of Cr(VI). The polymer was analyzed by FT-IR spectroscopy, FE-SEM, and mercury porosimetry, and the chemical structure, surface morphology and pore characteristics of the polymer were confirmed. The pH of the Cr(VI) solution strongly affected the performance of the adsorbent, and the best removal efficiency was obtained at pH 2. In the kinetic studies, the q_e value determined from the pseudo-second-order model was similar to the experimental q_e value, and this model showed the best correlation. The isotherm data were better fit by the Langmuir adsorption isotherm model than the Freundlich isotherm model, and the maximum adsorption capacity was 166.24 mg/g.