Environmentally benevolent urea modifiedSaccharum bengalenseas a high capacity biosorbent for removal of Pb(II) ions: metal uptake modeling and adsorption efficiency

Abstract

Sorption studies of hyper toxic Pb(II) ions from aqueous solution were investigated on simple and urea modified Saccharum bengalense (UMSB) biosorbent. Various experimental parameters including pH, temperature, and contact time were studied to evaluate the adsorption behavior. The equilibrium modeling showed that the biosorption data were better represented by the Langmuir and Freundlich models rather than other studied models. Thermodynamic parameters such as changes in standard free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) revealed the spontaneous, endothermic, and feasible nature of adsorption process. The biosorption process followed the pseudo-second-order (PSO) model. The intraparticle diffusion model was applied to investigate the rate determining step. The biosorption efficiency of urea modified biosorbent has also been compared with unmodified material. It was found that the sorption capacity (qm) increased from 4.73 to 12.65 mg/g on modification. The results of the present investigation suggested that UMSB can be used as an environmentally and economically feasible alternative biosorbent for the removal of Pb(II) from aqueous solutions.