Determination of Color Removal and Fading Performance of Environmentally Friendly Chemical Alternatives to Hydrosulfite in Reactive Dyed Cotton Knitted Fabrics Depending on Dye Chromophore

Abstract

ABSTRACT As is known, color stripping can be done with oxidizing or reducing agents. Today, reactive dye stripping is conventionally carried out via reductive method using hydrosulfite. However, from an environmental point of view, the use of more ecological chemicals has gained importance. In this study, it is aimed to determine the performances of reducing and oxidizing chemical alternatives to hydrosulfite, depending on the reactive dye chromophore. On the other hand, it was also aimed to provide a color fading effect on reactive dyed cotton fabrics with a treatment applied after dyeing. For this purpose, color stripping and/or fading effect was investigated on cotton knitted fabrics dyed with four different reactive dyes having anthraquinone (Reactive Blue 19), phthalocyanine (Reactive Blue 21), monoazo (Reactive Red 239) and metal azo (Reactive Red 23) chromophores. Studies were carried out with hydrosulfite, sodium hydroxymethane sulfinate and potassium persulfate at five different concentrations. It can be said that sodium hydroxymethane sulfinate and potassium persulfate can be used as an alternative to hydrosulfite in red dyes and blue dyes, respectively. COD and BOD values of wastewater of potassium persulfate treatment was found to be lower than hydrosulfite, which indicates that it is an ecological alternative over hydrosulphite.