Arsenic removal by adsorption on activated carbon in a rotating packed bed

High gravimetric technology or HIGEE is a novel technique which uses centrifugal force in a rotating packed bed (RPB) contactor. In RPB, a doughnut shaped bed is spun at high speed to allow fluid to flow through an adsorbent bed at a high velocity. Centrifugal force enhances the adsorption process with increased mass transfer coefficient. In this study, the optimum condition of the working parameters of a RPB contactor for arsenic removal by activated carbon was investigated and optimised by Taguchi method. Five parameters, namely rotating speed, feed rate, packing density, initial concentration and initial solution pH were considered in determining the initial optimal condition in a L16 orthogonal array. According to the signal to noise ratio (S/N), the optimum condition obtained from the L16 experiments are rotating speed of 1600 rpm, feed rate of 50 L/h, packing density of 510 kg/m ³, initial concentration of 150 mg/L and pH of 3. Depending upon the delta value, which is the difference between the highest and lowest S/N ratio, it was found that the initial concentration was the least affecting factor and pH could be fixed at 3 for practical purposes.