Physicochemical conditions for adsorption of lead from water by rice husk ash

Abstract

The effects of physico-chemical parameters such as pH, temperature, and lead concentration on the efficiency of lead adsorption by rice husk ash were determined. Rice husk was incinerated at 800 °C for 6 h and then activated with 0.5 M HCl. Rice husk and rice husk ash (RHA) were characterized using scanning electron microscopy and X-ray fluorescence. Batch adsorption tests were conducted at different pH, temperature, and initial lead concentration. Kinetic studies were conducted at optimum pH of 3.0. The optimum lead removal of 80% was recorded at pH 3.0. Efficiency of lead removal by RHA decreased to 45% as pH increased to 9.0. Freundlich, Langmuir, Temkin, and Dubinin Radushkevich (D-R) isotherms performed acceptably well, with R2 values of 0.954