One-step bleaching process for cotton fabrics using activated hydrogen peroxide

► Thiourea was used to activate hydrogen peroxide in bleaching of cotton fabrics. ► Bleaching was carried out at relatively low hydrogen peroxide concentration. ► Bleached fabrics showed acceptable whiteness and good tensile properties. Cotton fabric was bleached in a simple and economic process using a bleaching system composed of hydrogen peroxide activated with thiourea. Different bleaching trials were carried out with varying hydrogen peroxide and thiourea concentrations, as well as the bleaching medium temperature. The obtained results reveal that bleached cotton fabric with satisfactory whiteness index and reasonable tensile strength can be obtained by treating the fabric at 90°C in a bleaching bath containing 6g/l hydrogen peroxide, 1.5g/l thiourea and 1g/l non-ionic wetting agent using a material to liquor ratio of 1:20. These optimum conditions lead to completion of the bleaching process in a reasonable duration of 1h. Lower concentrations of the activator thiourea were found to prolong the bleaching duration without getting satisfactory whiteness index. Higher concentrations of the activator were found to cause early termination of the oxidizing species leading to bad whiteness index.