Adsorption of toxic organophosphorus pesticides from aqueous medium using dextrin‐graft‐poly(2‐acrylamido‐2‐methyl propane sulfonic acid‐co‐acrylic acid) copolymer: Studies on equilibrium kinetics, isotherms, and thermodynamics of interactions

Abstract

AbstractA graft copolymer was prepared by grafting a mixture of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) and acrylic acid (AA) monomers onto the dextrin polysaccharide backbone by free radical copolymerization technique using potassium peroxydisulfate as an initiator in water medium. Several characterization techniques like FT‐IR, 1H and 13C NMR, XRD, SEM, and EDAX analyses were used to characterize the synthesized polymer. The polymer was used as an efficient adsorbent for the removal of toxic pesticides namely dimethoate (DM), chlorpyrifos (CP), and phosalone (PL) from their aqueous solutions. Various operating variables such as kinetic, isotherm, and thermodynamic parameters were investigated for the three pesticides. The pesticide adsorption process over polymer surface was directed by pseudo‐second‐order kinetic model. Langmuir and Dubinin–Radushkevich isotherms both correlate well with the equilibrium data. Maximum adsorption capacity () of the polymer was found to be 172.4 mg g−1 for DM, 121.95 mg g−1 for PL, and 108.69 mg g−1 for CP. Thermodynamic parameters showed that the selected pesticides' adsorption onto the polymers was a spontaneous and endothermic process. The preferential pesticide sorption by the graft copolymer followed the order .