LAUSR

Abstract In this research, Hyper-cross-linked polystyrene was used for simultaneous removal of nickel and lead ions. The necessary number of experiments and optimum values of each factor were determined using response surface methodology (RSM). The optimum value of temperature, nickel, and lead concentrations, and pH was obtained 60 ℃, 50.715 mg/L, 80 mg/L, and 7 respectively, for Ni(II) adsorption in which the nickel uptake and selectivity were calculated 146.66 mg/g and 0.511, respectively. The optimum value of temperature, nickel, and lead concentrations, and pH was obtained 65 ℃, 80 mg/L, 40 mg/L, and 7 for Pb(II) adsorption in which the lead uptake and selectivity were calculated 137.272 mg/g and 3.951, respectively. The different isotherm models have been applied for both single and multi-component systems. It was concluded that both single and multi-component systems obeyed Freundlich isotherm model, which demonstrated the heterogeneous and multi-layer of the adsorbent. Besides, thermodynamic parameters such as ΔH°, ΔS°, and ΔG° expressed the exothermic and spontaneous nature of the adsorption of nickel and lead ions. Finally, the value of ΔH° for nickel and lead ions was lower than 40 kJ/mol, which implied the process was physical.