Decolourization of Congo Red Dye using Solar/H2O2 Process

Abstract

The Congo red dye was decolourized by advanced oxidation process using solar/H₂O₂ method and the effect of various parameters on decolourization like pH, H₂O₂ concentration, dye concentration, solar light intensity, additives, COD and TOC removal studies and kinetic studies were investigated. The photodegradation process was done by exposing dye solutions with the concentration of 100 mg/L treated with 50% H₂O₂ to sunlight with the lux intensity range of 60,000-90,000 lux. The best possible pH 2 with an optimal H₂O₂ concentration of 1000 mM to achieve 100% decolourization within the period of 5 h. The kinetic studies done on H₂O₂ concentration also proved that the high solar light intensity leads to higher decolourization and low solar light intensity leads to lesser decolourization. Addition of additives like H₂PO₄^– and Cl^– leads to a decrease in the rate of decolourization. The removal of COD and TOC removal was found to be 83.26% and 5.18%, respectively.