Sorption potential of styrene-divinylbenzene copolymer beads for the decontamination of lead from aqueous media

The decontamination of lead ions from aqueous media has been investigated using styrene-divinylbenzene copolymer beads (St-DVB) as an adsorbent. Various physico-chemical parameters such as selection of appropriate electrolyte, contact time, amount of adsorbent, concentration of adsorbate, effect of foreign ions, and temperature were optimized to simulate the best conditions which can be used to decontaminate lead from aqueous media using St-DVB beads as an adsorbent. The atomic absorption spectrometric technique was used to determine the distribution of lead. Maximum adsorption was observed at 0.001 mol L-1 acid solutions (HNO3, HCl, H2SO4 and HClO4) using 0.2 g of adsorbent for 4.83×10-5 mol L-1 lead concentration in two minutes equilibration time. The adsorption data followed the Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) isotherms over the lead concentration range of 1.207×10-3 to 2.413×10-2 mol L-1. The characteristic Freundlich constants i.e. 1/n=0.164±0.012 and A=2.345×10-3±4.480×10-5 mol g-1 have been computed for the sorption system. Langmuir isotherm gave a saturated capacity of 0.971±0.011 mmol g-1, which suggests monolayer coverage of the surface. The sorption mean free energy from D-R isotherm was found to be 18.26±0.75 kJ mol-1 indicating chemisorption involving chemical bonding for the adsorption process. The uptake of lead increases with the rise in temperature. Thermodynamic parameters i.e. G, H, and S have also been calculated for the system. The sorption process was found to be exothermic. The developed procedure was successfully applied for the removal of lead ions from real battery wastewater samples.