Abstract
Adsorption of toluene onto acid activated clay was carried out. Modified clay was prepared by acid attack (H2SO4) on raw material. Response surface methodology based on a 2-level, 4-variables central composite orthogonal design was used to evaluate the effects of important parameters on the adsorption of toluene on to activated clay. Temperature (53.8-96.2 degrees C), contact time (0.57-6.93 h), mass ratio of liquid/solid (3.38-7.62) and strength of acid (7.75-57.24%) were chosen as process variables for the optimization. Of these parameters, temperature reaction and time had greater impact on toluene adsorption than did the other parameters. Analysis of variance (ANOVA) shows a good agreement between theoretical analysis and experimental data. The validity of model is verified by an experiment at the optimum conditions. The optimum conditions for the maximum adsorption of toluene onto activated clay are: temperature of 96.2 degrees C, a contact time of 6.93 h, a liquid/solid ratio of 5.98 and strength of acid of 32.94%. Since the predicted values and the actual experimental value obtained for the maximum adsorption of toluene are within 95% confidence intervals, the final model is considered valid and has satisfactory predictive ability.