Adsorption studies of toxic organic pesticides from aqueous medium by sodium alginate‐cl‐poly (allyl amine‐co‐acrylic acid)/copper oxide nanocomposite hydrogel: Isotherms, kinetics, and thermodynamics

Abstract

The sodium alginate (SAG) cross‐linked poly (allyl amine‐co‐acrylic acid)/copper oxide [SAG‐cl‐poly(AAM‐co‐AA)/CuO] nanocomposite hydrogel (SNCHG) was synthesized by using a free radical initiated cross‐linked copolymerization process in‐situ. Several characterization techniques namely FTIR, PXRD, FESEM with EDAX, TGA, and BET analysis were employed to characterize the synthesized SNCHG. Water swelling properties together with swelling kinetics of SNCHG were evaluated. The highest swelling (35% after 30 minutes) was found at pH 8. The adsorption property of the developed nanocomposite hydrogel (SNCHG) was evaluated in three pesticides' solution namely chlorpyrifos (CP), phosalone (PL), and 4,4'‐ dichloro diphenyl dichloro ethane (DD) in water medium. Several factors affecting the adsorption like solution pH, time of adsorption, amount of pesticides, etc. were evaluated. The maximum adsorption were found to be 96.9% for CP at pH 7, 95.85% for PL at pH 7, and 86.72% for DD at pH 4. Pseudo‐second order kinetics and both Freundlich and Dubinin–Radushkevich adsorption isotherms were followed in all the three cases. Maximum adsorption capacity (Qm) were found to be 507.61, 158.22, and 132.97 mg g−1 for CP, PL, and DD, respectively. The adsorption process was endothermic in nature and spontaneous.Highlights A novel CuO Nps embedded sodium alginate‐based hydrogel is developed. Increment of surface area and water swelling property are illustrated. The hydrogel exhibits excellent adsorption property towards pesticides. The observed affinity of adsorption is chemisorption.