Biosorption of Ni (II) from aqueous solutions and real industrial wastewater using modified A. barbadensis Miller leaves residue powder in a lab scale continuous fixed bed column

Abstract

In the present studies, adsorption behavior of modified A. barbadensis Miller leaves (MABL) residue powder, an agricultural and herbal waste was investigated to remove Ni (II) ions from aqueous solutions in a fixed-bed adsorber continuous column. Experiments at various operating conditions of bed heights (4 cm, 6 cm, 10 cm), influent Ni(II) ion concentrations (20, 40, and 60 mg/l) and flow rates (10, 20, and 30 ml/min) were performed in order to study and optimize the performance of the fixed bed adsorber column. In this study, the maximum capacity of MABL powder was found to be 16.28 at 6 cm bed depth, influent Ni (II) concentration of 20 mg/l and flow rate of 10 ml/min. Commonly used empirical models for fixed bed adsorption kinetics, namely Adams–Bohart model, Thomas model and Yoon and Nelson kinetic models were tested to approximate and predict the behavior of the column. Based on the statistical analysis of fitting of data to these models, the Yoon-Nelson model was found to approximate the behavior of the column in these studies with R2 values in the range of 0.97–0.99. Finally, desorption studies indicated that Ni (II) loaded and regenerated biosorbent could be used even after three consecutive sorption cycles. MABL was also used to remove Ni(II) from a real wastewater in fixed bed column. The results are promising and shall serve to design the MABL based fixed bed adsorbers in order to obtain cleaner and sustainable treatment of industrial wasters containing Ni(II) ions.