Modelling of lead(II) ion adsorption onto poly(thiourea imine) functionalized chelating resin using response surface methodology (RSM)

In this study, the adsorption of lead(II) ion from an aqueous solution, using poly(thioureaimine) (PTUI) functionalized chelating resin and its optimization, were investigated. Solution pH (6.5), initial lead(II) ion concentration (300 mg/L) and temperature (38 °C) were found to be optimum for lead(II) ion adsorption by RSM. An ideal experimental design was carried out, based on the Box–Behnken design using response surface methodology (RSM). Based on the ANOVA statistical value, the adsorption of lead(II) ion onto PTUI has been found to be highly significant, with very low probability (p) values (<0.001). The kinetic experimental data were examined, using the pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models. The adsorption kinetic results show that the experimental data fits well with Ho's pseudo-second order kinetic model. The thermodynamic studies indicate that the adsorption process is endothermic in nature. Isosteric studies show that PTUI has a heterogeneous surface.