SYNTHESIS AND CHARACTERIZATION OF MIXED ALUMINA-ZIRCONIA COMPOSITE FOR THE REMOVAL OF DYES FROM EFFLUENTS

Abstract

Mixed Al2O3-ZrO2 composite was prepared by combustion method. The resulting composite was characterized by SEM, SEM-EDAX and XRD analytical techniques. The material was used for the treatment of effluents to remove dyes. The results showed the presence of Al, Zr and O thus suggesting the formation of alumina-zirconia composite. The composite was effective in the removal of Congo red and Methylene blue from effluents. The removal process was pH dependent. Acidic pH favoured Congo red removal while basic pH favoured Methylene blue adsorption with the Al2O3-ZrO2 composite. Increasing temperature from 25 to 65oC caused a reduction in percentage of Congo red adsorbed from 88.45 - 68.99 % while Methylene blue adsorbed reduced from 90.23 - 75.62 %. Adsorption of both dyes can best be described by second order kinetics model and the process can be fitted to Langmuir, Freundlich and Temkin isotherm models. This signifies cooperative adsorption. The thermodynamic parameters calculated showed positive ΔGo and negative ΔHo indicating non-spontaneous and exothermic reaction.