Colorimetric Analysis of Cotton Textile Bleaching through H2O2 Activated by UV Light

The bleaching process is one of the steps of cotton fabric manufacture. Traditionally, the most common bleaching procedure is based on the use of a hydrogen peroxide (H2O2) solution in alkali pH associated with high temperature. In this study, we investigated the possibility of applying a photolysis technique, combining ultraviolet (UV) light and H2O2 in acidic pH to promote raw cotton fabric bleaching, without adding heat and stabilizers to the process. A colorimetric analysis was performed to assess the bleaching procedure in the samples. The experiment consisted in moistening cotton fabric samples with H2O2 and then illuminating them with UV light with different doses, ranging from 0.6 to 36 J cm-2. Our findings have shown that it is important to balance the hydrogen peroxide and the amount of delivered UV light to the cotton fabric in order to achieve a satisfactory whiteness without compromising the fabric mechanical properties.