Effect of Additives on Decomposition of Methyl Orange and Congo Red Dyes Found in Industrial Wastewater

A number of textile industries are using different types of dyes which can be a threat to the environment when they are directly exposed without any treatment. The advanced oxidation process (AOP) has become one of the popular methods in which the dye molecules are degraded using microwave irradiation. This method has become popular due to its eco-friendly and cost-efficient characteristics. In this article, the author has reported the degradation of two azo dyes, named methyl orange (MO) and congo red (CR), in the presence of inorganic salts, some additives like charcoal, H2O2, CCl4, tert-butyl alcohol (TBA), glucose and sucrose. A comparative study was conducted to find out the relative degradation rate enhanced by various additives. For both of the dyes, it was found that charcoal was the most effective additive and significantly enhanced the degradation rate mainly due to its high adsorption capability. TBA was found to be the least enhancer. The order of effectiveness based on the irradiation period for MO was 0.01g charcoal > 20 ml NaCl > 20 ml Na2SO4 > 20ml glucose> 10 ml sucrose > 100 μL CCl4 > 200 μL H2O2 > pure MO > TBA. On the other hand, the order of effectiveness for CR for the same condition of irradiation was Combined additives>0.01g charcoal > TBA > 100 μL CCl4> pure CR.