Environmentally Sensitive Vinylpyrrolidone/Methacrylic Acid Inter-Complex Amphoteric Hydrogel: Preparation, Characterization, and Use in the Binding of Copper Ions

In this study for wastewater remediation, we aimed to prepare Environmentally Sensitive Hydrogels (ESHs) with specific properties to remove copper (Cu2+) from wastewater. ESHs were prepared with inter-complex and amphoteric properties by the free radical polymerization method. We prepared two monomers, vinylpyrrolidone (VP) and Methacrylic Acid (MA). N,N’-methylenebisacrylamide was a cross-linker agent to prepare ESHs for binding Cu2+ to remove from wastewater. To characterize the structural behavior of synthesized ESHs, we used FT-IR. Thermal properties were investigated by using TGA. We used Scanning Electron Microscopy (SEM) micrographs for morphologic studies. Swelling and diffusion studies were performed at different pH, temperatures, and salt solutions. The amphoteric property and inter-complex formation between VP and MA were monitored by UV spectroscopy. In the Cu2+ bindings onto ESH experiments, a Langmuir-type (L) adsorption was observed regarding the Giles classification system. Binding parameters such as equilibrium constant (KL), monolayer coverage (Qm), and maximum fractional occupancy (FO%) were calculated as 0.16 L 1/gESH, 30 MgCu2+1/gESH, and 81%, respectively. We found a powerful electrostatic effect between the ionic part of ESH and cationic Cu2+. These interactions denote the removal of cationic heavy metals and organic toxic wastes for water treatment.