Isothermal, kinetic, and thermodynamic studies on copper adsorption on modified styrene acrylonitrile copolymer

The research includes the synthesis of copolymeric material and its chemical modification in order to enhance its adsorptive properties toward copper ions removal. The copolymeric material of acrylonitrile (AN) and styrene (St) was prepared in the ratio of 70:30% V/V, respectively, using 1-propanol as a co-solvent using the precipitation polymerization technique. The prepared copolymeric material undergoes an alkaline modification process using sodium hydroxide. The influence of the modification process variables has been studied on the removal of copper ions where the agitation rate was found to be the most effective parameter in this process. The copolymer chemical structure was investigated through Fourier-transform infrared spectrum, indicating the evaluation of carboxylate groups at 3497 cm−1 after sodium hydroxide treatment. The copolymer thermal stability has been increased by the modification process which was confirmed by thermal characterization. The morphological structure and particle size of the copolymer particles were investigated to be 53.6 nm. The removal process parameters have been studied to show pH variation as a critical parameter in this stage of application. The maximum removal percent was achieved after 90 min to reach 89.6%. The adsorption capacity of the modified (St–AN) copolymer to copper solution was found to be 20 g/L. Thermodynamic, isothermal, and kinetic studies were done where it showed the adsorption process to be spontaneous, thermodynamically favorable, and endothermic in nature.