Aqueous Cadmium Removal by Adsorption on Barley Hull and Barley Hull Ash

Abstract

The contamination of water by toxic heavy metals through the discharge of industrial, mining and agricultural wastewaters is a worldwide environmental problem. Metals can be distinguished from other toxic pollutants, since they are non-biodegradable and can accumulate in living tissues, thus becoming concentrated throughout the food chain. Cadmium is a highly toxic element affecting the environment. Excessive human intake of Cd leads to damage of kidney and renal system, skeletal deformation (Itai-itai), cardiovascular diseases and hypertension. Severe gastrointestinal irritation, muscular pain, anemia, teeth discoloration, loss of smell and possible necrotic changes in the liver and kidney can also occur. Cadmium is also known carcinogen. The treatment of cadmium contaminated water is similar to that of many metal contaminated effluents. The main techniques, which have been utilized to reduce the heavy metal ion content of effluents, include chemical precipitation, coagulation, lime precipitation, solvent extraction, electrolytic processes, membrane separation, ion-exchange and adsorption. In the last few years, adsorption has been shown to be an economically feasible alternative method for removing trace metal from wastewater and water supplies. Activated carbon Aqueous Cadmium Removal by Adsorption on Barley Hull and Barley Hull Ash