Electrochemical studies on textile dye naphthol yellow S with particular reference to colour removal

Department of Environmental Chemistry. Jiwaji University, Gwalior-474 011, India E-mail : gwlsosmica@sancharnet.in Fax: 91-751-2346209 Manuscript received 9 September 2003, revised 23 August 2004, accepted 9 December 2004 Aromatic nitro dyes arc resistant to chemical and biological oxidation and to hydrolysis because of electron withdrawing nitro groups. Consequently they are environmentally persistent and remediation of waste streams and contaminated water is difficult. In the present work, the electrochemical study has been carried out on the nitro acid dye naphthol yellow S predominantly used in textile dyeing. On the basis of results of the electrochemical study experimental conditions arc optimized for the controlled potential electrolysis of the model dye. Complete decolourisation resulted after 1 to 3 h of controlled potential electrolysis. Kinetics of decolourisation was monitored and half-life period determined. Chromatographic study revealed formation of single decomposition product and COD decreased substantially in the decolourised solution