REMOVAL OF ZINC USING AGRICULTURAL WASTES BY COLUMN ADSORPTION METHOD

The adsorption of Zinc ions in a fixed bed column using rice husk ash, Ageratum Conyzoides ash, sugarcane bagasse ash and RSA was investigated. Adams-Bohart model and Yoon-Nelson kinetic models were used to analyze the column performance. The rate constant for Adams-Bohart model decreases with increase in bed depth. Adsorption capacity for the adsorption of Zinc obtained from Adams-Bohart model ranged from 484.8 mg/L to 1653.4 mg/L for sugarcane bagasse, 1057.8 mg/L to 2550.2 mg/L for rice husk ash, 727.2 mg/L to 1830.3 mg/L for Ageratum Conyzoides and 375.3 mg/L to 1308.0 mg/L for RSA. The maximum adsorption capacity increases with increase in bed depth. For Yoon-Nelson model, the rate constant decreases with increase in bed depth. The time required for 50% breakthrough obtained from Yoon-Nelson model ranged from 39.89 mins to 882.76 mins for sugarcane bagasse, 41.49 mins to 954.30 mins for rice husk ash, 38.38 mins to 916.55 mins for Ageratum Conyzoides, and 31.09 mins to 733.28 mins for RSA. The time required for 50% breakthrough increases with increase in bed depth. The kinetic data fitted well to both models with R2 values generally above 0.9.