Pb (II) sorption by acidically modified Cicer arientinum biomass

In this study, efficacy of native and acidically modified Cicer arientinum pod biomass was investigated for Pb (II) removal using metal ion concentration, kinetic, sorbent dose, pH and pretreatment as operational parameters. The metal uptake of biomass increased as a result of pretreatments and maximum sorption capacity (171.28 mg/g) was shown by H3PO4 modified biomass. The sorption capacity increased in the order H3PO4 > H2SO4 > HCl > native, with increase in metal concentration. The equilibrium data was analysed using different sorption models to know sorption mechanism and results of ANOVA showed that Dubinin–Radushkevich model is fitted well to the experimental data. Sorption rate was slow because equilibrium was attained within 7 h and rate was best described by pseudo-first-order, second-order rate equation, Bangham and intraparticle diffusion models. Sorption capacity was maximum at pH 4 and it was observed also that sorption capacity decreased but % removal increased with increase in biosorbent dose.