Study ZnO Nano Particles and Activated Carbon Produced from Agricultural Waste Efficiency on Removing Direct Blue 71

Abstract

The Azo group has been one of the chemical structures in classifying dyes which is important due to its cancer causing and negative effects on the environment and interference with the ecology of the water bodies. In this study photo catalytic process was used due to its unique features in decomposition of pollutants to mineral compounds and also the physical process of agricultural waste adsorption to remove DB71 in 3 ways of adsorption/photo catalytic, photo catalytic/adsorption, and simultaneously adsorption and photo catalytic. The results have shown that in all 3 systems in pH=9 with initial dye concentration of 50 mg/L, 100 percent removal efficiency were achieved with optimal ratio of AC/ZnO in the presence of two adsorbent of walnut and almond shells of 0.75/0.096 and 1/0.096 (in adsorption/photo catalytic), 0.024/0.75 and 0.024/1 (in photo catalytic/adsorption) and 0.75/0.288 and 0.75/0.288 (in simultaneous adsorption-photo catalytic), respectively.
In the optimum conditions in all the three systems, COD removal was obtained 47.22, 49.6, 42.21, 39.18, 62.23 and 63.15 percent respectively after 30 hours.