Electrochemical degradation of C. I. Acid Orange 7

The electrochemical oxidation of C. I. Acid Orange 7 (AO7) was performed on a boron doped diamond electrode (BDD). Bulk electrolysis was studied using two different supporting electrolytes-KCl and Na2SO4. The influence of electrolyte concentration, initial dye concentration and current density on the degradation rates was investigated. Samples were collected at pre-selected intervals and absorbance measurements and chemical oxygen demand (COD) tests were performed, to compare the rates of colour and COD removal in each case. From the COD measurements over the time of electrolysis mass transfer coefficients were determined, and the current efficiency was estimated using a theoretical model. Results have shown an almost complete colour removal and COD removal, higher than 90%. A preliminary electro degradation study of an effluent from an UASB reactor, used on the biodegradation of a textile wastewater containing AO7, was also performed with colour and COD removals of 98% and 77%, respectively. (C) 2003 Published by Elsevier Ltd.