Photo oxidation of (Azure A) dye by UV-enhanced ozonation :optimization and kinetics study.

Abstract

The photo degradation of Azure A (AA) dye by using ozone as a stimulating agent with ultra violet radiation (O3/UV) has been studied. All dye solutions has been subjected to color removal. The study includes the effect of the concentration of dye solution, temperature, pH, air flow rate, and the light intensity on the degree of color removal. It was found that the increase in dye concentration leads to adecrease in removal rate. Also, the rate of dye removal increases with the increase in temperature. The activation energy reached (13.06 kJ/mole). Concerning pH is the removal decreases in acidic medium because the ozone doesn’t decompose to hydroxyl radicals. Contrastively, the rate of removal increases in basic medium because of the decrease of solubility of ozone and the formation of hydroxyl radicals. Another important result is that the rate of air is associated positively with the rate of dye removal. Lastly, it is noticed that the more light intensity increased, the more the rate of color removal increased. Generally , The ratio of the chemical oxygen demand (COD) increases with the increase of color removal. The maximum ratio of color and COD removal, that was reached (at 45 oC ), was 98.1% and 68% respectively.