Optimization Study of the Removal of Atrazine from Aqueous Solution on to Composite Activated Carbon-Silver Using Response Surface Methodology

Abstract

Activated carbon based oil palm shells were prepared by physical activation using steam which was further grafted with silver. The Response Surface Methodology (Doehlert design) was used to optimize both the impregnation of silver and the atrazine removal. The effects of three variables of preparation conditions of the composite activated Carbon-Silver (AC-Ag): Concentration of silver, impregnation temperature and impregnation time on the atrazine removal (Y1) was investigated on one hand. In another hand, three variables of atrazine removal from liquid phase: Temperature, pH and ratio of Atrazine/CaCl2 (r(Atraz/CaCl2)) on the adsorption capacity of atrazine (Y2) were also investigated. Based on the Doehlert designs, the quadratic models were developed to correlate the preparation variables and the adsorption variables to the response. The optimum conditions of preparation of AC-Ag were found to be: Concentration of silver of 0.063 mol/L, impregnation temperature of 223˚C, impregnation time of 1.3 hand atrazine removal of 384.62 mg/g. The optimum conditions of atrazine adsorption were found to be: Temperature of 25.0˚C, pH of 7.7 and r(Atraz/CaCl2) of 0.37 which gave 209 mg/g of atrazine adsorption capacity. These results demonstrated that the preparation and adsorption conditions have a significant influence on the removal of atrazine.