Enhanced Removal of Arsenite from Ground Water by Adsorption onto Heat-Treated Rice Husk

Abstract

The effect of heat treatment for rice husk was investigated on the removal of arsenite in ground water by the adsorption onto the rice husk surface. The heat treatment was performed at the temperature from 80˚C to 300˚C in the closed system under anoxic environment. The continuous adsorption column method was applied for the removal of arsenite. The removal efficiency (75%) with rice husk treated at 150˚C was better compared to those (54%) obtained with untreated rice husk. Therefore, the heat treatment of rice husk at relatively low temperature was effective for the enhancement of arsenic removal from water. The treatment conditions of As removal from aqueous solution were optimized. The developed treatment technique was applied into the real ground water sample in Bangladesh. The As concentration in sample water after treatment was approximately 18 and 8 μg/L, which was below the WHO guideline value of maximum admissible level of arsenic in ground water for Bangladesh (50 μg/L). The developed technique might become a potential avenue for simple and low cost arsenic removal methods.