Preparation of Highly Active Surface by Free Radical Copolymerization of Hydrogel for Removal of Copper Ions from Aqueous Solutions: Isotherm and DFT Studying

The possibility of using a natural, ecologically friendly, low-cost, and readily available source to remove the Cu (II) dye from the aqueous solution by preparing the SA-g-P(AAC-co-AM)/AC hydrogel composite by free radical copolymerization. The overlay hydrogel was diagnosed using several techniques, like TEM, FESEM and XRD. The results showed that as the weight of the hydrogel increased, the adsorption percentage increased, ranging from 4.55% to 84.76%. It is noted that with an increase in the copper ion concentration of (5-50 mg/L), the adsorption efficiency increases (4.65 mg/g to 29.87 m/g). However, with an increase in the copper ion concentration, the removal percentage decreases (97.87% to 44.35%). Therefore, the best concentration (30 mg/L) and the equilibrium time for Cu (II) adsorption for 1 h, with a rapid initial adsorption rate that slowed over time. Adsorption isotherms indicate a multilayer process on a heterogeneous surface. Adsorption equilibrium studies were investigated by Langmuir and Freundlich isotherm models. The Freundlich model provided the results with better efficiency (Qe=43.567 mg/g). Calculations of DFT approve that electrostatic interaction, electron localization function, and metal surface coordinate interaction were the main steps for adsorption mechanisms in the synergistic interactions among copper ions and SAAM-AC surface.