Study of biomass of Reynoutria japonica as a novel biosorbent for removal of metals from aqueous solutions

Abstract

In the present study, the sorption capacity of plant biomass has been studied; more precisely the ability of biomass of roots, stems and leaves of an invasive plant Reynoutria japonica to bind up Zn2+ ions from aqueous solutions. The results of this biosorption study revealed that the rate and extent of uptake were affected by pH level, contact time and initial metal concentration. The equilibrium sorption data for the metal system at pH 6.0 was described by the Langmuir isotherms model. The sorption equilibrium, when expressed by the Langmuir and Freundlich equations, indicated that the process was in compliance with the Langmuir isotherm, which showed the best match. The maximum uptake of metal ions was obtained at pH 6.0. The highest sorption capacity for Zn2+, qmax = 17 mg/g, was achieved using the biomass from leaves. Removal of Zn2+ with 1g/l biosorbent from leaves was almost 77%, when zinc present in low concentrations, whereas it was lower at higher concentrations. With higher biomass doses the removal efficiency of Zn2+ was high even at high initial concentrations of the metal.