Column optimization of adsorption and evaluation of bed parameters-based on removal of arsenite ion using rice husk

The objective of this study deals with column optimization of adsorption-based on removal of arsenite ion using rice husk. The parameters affecting the column adsorption study, i.e., influent-concentration, bed depth, and flow rate, were optimized. The range of parameters, i.e., influent-concentration (15-50 mg/L), flow rate (20, 35, 45, and 60 mL/min), and bed depth (15-60 mm), were studied experimentally. Kinetics models Bohart-Adams and Hutchins were studied to measure the amount adsorbed, depth of mass transfer zone, saturated concentration, and time observed at 10% & 90% breakthrough. The percentage amount adsorbed q_m enhanced with enhancement in bed depth but got reduced with influent ions concentration and volumetric flow rate. Established model Bohart-Adams and Hutchins equations were used for calculation of mass transfer zone which came out to be 51 mm. An adsorption capacity (q_m) of 4.5 mg/g for arsenite ions was achieved at optimum parameter values of 60 mm of bed depth, 20 mL/min volumetric flow rate, and 50 mg/L of influent ions concentration. The adsorption bed parameters were also evaluated using Hutchins and Michaels equations. The column study proved rice husk to be a potential adsorbent for the adsorption of arsenite.