ADSORPTION POTENTIAL OF BURNT PEANUT SHELLS FOR REMOVING PHENOL

Abstract

Agricultural waste material has been tested for adsorption of organic and inorganic pollutants from industrial wastewater and they were found exceptionally well in terms of cost by many researchers. One such waste material is peanut shell which has been studied and tested for adsorption of phenol in this study. Ashes from Peanut shell were prepared by heating the raw material at 400 oc for three hours. Ashes of size ranging from 0.5 mm to 1 mm with varying initial phenol concentration were used to analyze the adsorption potential at different pH. Adsorption capacity of peanut shell was measured by batch and fixed bed-continuous flow experiments. Results from the batch experiments indicated that the percentage of phenol removal decreased with increasing initial phenol concentration from 5 to 100 mg/L. Adsorption capacity was maximum at pH 4 and decreased gradually by raising pH. The kinetic data were fitted to the models of intra particle diffusion, pseudo-second order, and Lagergren's and followed more closely to the Lagergren's model. The isotherm equilibrium data were well fitted to the Langmuir model. The maximum adsorption potential by peanut shell ash per Langmuir isotherm was 13 mg/L at pH 4. In fixed bed-continuous flow experiments, the influence of the flow rate (15, 25, 60 ml/min) on the breakthrough curve was analyzed. The breakthrough time was strongly dependent on the inlet flow rate. The results for peanut shell ash were then compared previous studies performed on agricultural waste materials.