A study on the advanced oxidation of a cotton fabric by ozone

So-called sdvanced oxidation involves the generation of free radical hydrox y species. Ozone, a highly unstable compound, liberates such radicals, whic h can be used for bleaching. In this work grey cotton fabric was bleached w ith an ozone/oxygen gas mixture, and the effects of ozone concentration and treatment time on the properties of the bleached fabric were studied. The properties evaluated were whiteness index, strength, elongation, extent of impurities (size and wax) removed, degree of chemical modification (carboxy l and aldehyde groups) and reactive dye take-up. These properties were comp ared to those from conventionally bleached materials (acid desize-scour-per oxide/calcium hypochlorite bleach). The results show that an acceptable deg ree of whiteness (ready for dyeing) can be obtained by ozone bleaching in a very short time. This process is environmentally acceptable because it is does not use harmful chemicals, it requires a very low quantity of water, a nd bleaching is achieved in a very short time at room temperature.