Adsorption of Ag⁺ from Aqueous Solutions by Rice Husk

This paper reports the feasibility of using rice husk to remove Ag+ from synthetic wastewater. Effect of various adsorption parameters, namely, pH, adsorbent dose, initial silver concentration and contact time has been studied in batch systems. The results indicated that rice husk offered high removal efficiency, fast adsorption rate and high uptake capacity for Ag+ ions. The equilibrium was attained within 20 min and the maximum removal efficiency at 11g/L rice husk and at pH 2 was found to be 99.76%. The kinetic data was fitted well to pseudo-second order model. The isotherm adsorption data was well described by the Langmuir isotherm model and the maximum uptake capacity of Ag+ ions onto rice husk was found to be 42.43 mg/g.