Optimization by response surface methodology (RSM) for toluene adsorption onto prepared acid activated clay

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◦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◦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. L’adsorption du tolu`ene sur l’argile activ´ee par l’acide est r´ealis´ee. L’argile modifi´ee a ´et´e pr´epar´ee par attaque acide (H2SO4) de lamati`ere premi`ere. On a eu recours `a la m´ethodologie de surface de r´eponse bas´ee sur un plan d’exp´eriences orthogonal composite centr´e `a 2 niveaux et 4 variables afin d’´evaluer les effets des param`etres importants pour l’adsorption du tolu`ene sur l’argile activ´ee. La temp´erature (53,8◦C–96,2◦C), le temps de contact (0,57–6,93 h), le rapport massique liquide/solide (3,38–7,62) et la force de l’acide (7,75–57,24%) ont ´et´e choisis comme variables de proc´ed´e pour l’optimisation. Parmi ces param`etres, le temps de contact et la temp´erature ont le plus grand impact sur l’adsorption du tolu`ene. L’analyse de la variance (ANOVA) montre un bon accord avec l’analyse th´eorique et les donn´ees exp´erimentales. La validit´e du mod`ele est v´erifi´ee par une exp´erience dans les conditions optimales. Les conditions optimales pour l’adsorption du tolu`ene sur l’argile activ´ee sont: la temp´erature de 96,2◦C, le temps de contact de 6,93 h, le rapport liquide/solide de 5,98 et la force de l’acide de 32,94%. ´Etant donn´e que la valeur pr´edict´ee et la valeur exp´erimentale r´eelle obtenue par l’adsorption maximale du tolu`ene se trouvent dans un intervalle de confiance de 95%, le mod`ele final est consid´er´e comme valide et poss`ede une capacit´e de pr´ediction satisfaisante.