Decolorisation of Azo Dye (Congo red) from Synthetic Solution using Natural Coagulants

Abstract

The textile dying industry contains effluents which are harmful to human health and environment. In this research work, decolourisation of congo red dye was studied using natural coagulant like Moringa oleifera Seed Powder (MOSP) and Maize Seed Powder (MSP) which are suitable alternative for chemical coagulants in coagulation and flocculation process. Absorbance value was determined for various concentration of congo red dye by using a UV spectrophotometer and the calibration curve was drawn. Experiments were carried out for determining the percentage of decolorisation using MOSP and MSP. The different parameters such as pH, temperature, coagulant dose and flocculation time were optimized. The optimum decolorisation percentage of congo red was observed for natural coagulant MOSP with removal efficiency of 92% at coagulant dosage of 200 mg/l, temperature of 5000C, pH of 7.5 and flocculation time of 60 minutes. For natural coagulant MSP, Congo red decolorisation efficiency was found to be 65% at coagulant dosage of 50 mg/l, temperature 5000C, 5 pH and flocculation time of 90 minutes. Hence, it can be inferred that MOSP gives better decolorisation efficiency than MSP for Congo red removal.