Biosorption Characteristics of Indigenous Plant Material for Trivalent Arsenic Removal from Groundwater: Equilibrium and Kinetic Studies

A biomass derived from plant A. nilotica (leave) has been used for efficient removal of trivalent arsenic (As(III)) from aqueous media. The experiments were carried out to study the effects of different parameters i.e., biomass dosage, As(III) concentration, pH, temperature, and contact time. The equilibrium biosorption data were analyzed by the Langmuir and Freundlich isotherm models and satisfactorily both isotherm models could be fitted well. The biosorption mean free energy based on the D-R isotherm model was calculated in the range of 7.50–8.21 kJ mol−1. The data of thermodynamic parameters [enthalpy (ΔH°), Gibbs free energy (ΔG°), and entropy (ΔS°)] were identified that biosorption of As(III) onto studied biomass was spontaneous, feasible, and exothermic under the optimum experimental conditions. Kinetic estimations based on the experimental data demonstrated that the biosorption of As(III) followed the pseudo-second-order kinetics. The studied biomass was successfully applied for the removal of As(III) from contaminated groundwater samples of Jamshoro district.