VI-3-Cadmium Removal from Aqueous Solutions by adsorption on Sawdust.

Abstract

The presence of highly toxic Cadmium in effluent streams is a major environmental issue. Electroplating, mining and metallurgical operations and refineries are the major source of Cd present in wastewater streams. The present work deals with the determination of Cd removal capacity using sawdust which is a low cost adsorbent. The studies on adsorption of Cadmium were conducted by varying various parameters such as contact time, amount of adsorbent, and pH. Batch experiments and column studies were conducted to find out the adsorption capacity of sawdust. By batch adsorption studies, it has been found that the percentage of adsorption increased with contact time up to a specific time and increased with the adsorbent dosage reaching almost a constant value at a particular dosage. The percentage removal also increased with pH up to pH of 6-7 and then decreased. It has been found that the amount of adsorbate per unit weight of adsorbent increased with increasing contact time at all initial concentrations and equilibrium was attained within 3 hours for cadmium sawdust system. The equilibrium adsorption results were analyzed by Langmuir and Freundlich models to determine the mechanistic parameters associated with the adsorption process. The results showed that sawdust shows potential to be applied in waste water technology for heavy metal remediation.