Roles of Electrostatic Interactions in the Peroxide System for Bleaching of Cotton Fabric

Abstract

The industrial bleaching of cotton fabric is often carried out in an aqueous solution of hydrogen peroxide (H₂O₂) with the addition of sodium hydroxide (NaOH) at a boiling temperature. To overcome the higher energy consumption problem of the traditional bleaching system, activated peroxide systems are proposed by adding bleach activators to the bleaching system. The bleach activators react with H₂O₂ to generate more kinetically active bleaching components, which enable the cotton fabric to be bleached at lower temperatures. However, different bleaching components have different electronic properties. In this study, the electrostatic interactions between cotton fabrics and bleaching components were investigated, as well as the charge-regulation behavior of electrolytes and surfactants in the bleaching system. The research results showed that electrostatic interactions played an important role in bleaching by affecting the adsorption of bleach activators onto cotton fabric. Electrolytes and surfactants in the bleaching system could work as charge-regulation agent by effecting the adsorption of bleach activators onto cotton fabric by increasing or reducing the adsorption of bleach activators onto cotton fabric. This work proved the existence of electrostatic interactions between bleaching components and cotton fabric and also presented the charge-regulation behaviors during bleaching. It provides further understanding that the performance of the peroxide systems for bleaching depends not only on the chemical activities of the bleaching components but also on the electrostatic interactions between the bleaching components and cotton fabric.