Bleaching of Cotton Fabric by Electrogenerated Species—Decoloration of Coloring Matter by Electrolysis

Abstract

Decoloration of dyes such as methylene blue and tartrazine solutions is investigated by subjecting dye solution to electrogenerated oxygen or chlorine species in electrolytes at a Pt anode. Decoloration is weak in the presence of electrogenerated oxygen species but increases in the KCl electrolyte. Decoloration in this solution is accomplished by the electrogenerated hypochlorite ion. Also, when placed in contact with a Pt anode, cotton fabric dyed with reactive dyes is decolorized significantly after short-term electrolysis in an electrolyte containing KCl, but decoloration of dyed fabrics is very weak in an electrolyte that is free from KCl.