Environmentally Friendly Treatment of Textiles Using Electrochemically Generated O3-Water with UV Irradiation

Abstract

Recently, application of advanced oxidation technologies (AOTs) for environmental purification have received growing attention [1]. Especially electrolysis with boron-doped diamond (BDD) electrodes make it possible to generate various highly active oxidants such as O3 which can oxidize aqueous contaminants [2]. In this study, we introduce recent studies about environment-friendly “AOT-treatments” of textile by using of O3-water with UV irradiation instead of conventional treatments (scouring and bleaching) with environmentally persistent reagents. Fig. 1 shows the photographs of cotton bleaching by AOT. Cotton fabrics were treated by O3-water (1.0 ppm, 1.5 L/min, continuously generated from tap water) with UV irradiation (170 mW/cm2 @310-380 nm). After treatments, the fabrics were dried under room temperature and analyzed by reflection spectra. Fig. 2 left shows the reflection spectra and photographs of cotton fabrics. After 60 min of AOT, the spectrum and whiteness of the cotton are almost the same with conventional chemical-bleached one. But the only problem is “color reversion” by ironing (heating around 200°C). Heating of oxidized cellulose generates conjugated systems and yellow color (Fig. 2 right, green line). However, we found that reduction of oxidized cellulose by rongalite can prevent color reversion (Fig. 2 right, red line). Therefore, AOT-treatment is attractive to reduce energy consumption and cut waste in the fabric processing. Acknowledgements: Travel expenses for the attending PRiME 2020 were supported by The Tokyo Ohka Foundation for The Promotion of Science and Technology.[1] T. Ochiai and A. Fujishima, Journal of Photochemistry and Photobiology C: Photochemistry Reviews 2012, 13, 247.[2] T. Ochiai, S. Tago, M. Hayashi, K. Hirota, T. Kondo, K. Satomura, A. Fujishima, Electrochem. Commun. 2016, 68, 49. Figure 1