Influence of plasma surface pretreatment and triarylmethane dye on the photocatalytic performance of TiO 2 -chitosan coating on textile

Abstract

Abstract Treatment of household wastewater loaded with hair colorants by means of solar photocatalysis using TiO 2 -coated polyester/wool textile has been reported recently. In this work, the attributes of immobilized photocatalyst were enhanced; a textile support (polyester/wool blend fabric) was pre-treated by atmospheric and low pressure oxygen plasma prior to coating of the surface. Plasma pre-treatment contributed to hydrophilisation of support and overall resistance to wear of immobilized photocatalyst was improved. Moreover, TiO 2 -chitosan composite coating was modified by the addition of triarylmethane dye (C.I. Basic Blue 1; BB1). The sensitizing effect of the dye was observed during the first 180 min of photocatalytic treatment of greywater polluted by hair colorants under solar irradiation. Adversarially, the rate of photocatalytic degradation of bisphenol A (BPA) model solution under visible light was lower in the presence of BB1 in the photocatalyst formulation. According to the performed study of BB1 chemistry in aqueous solution, it was found that the dye undergoes two distinct photodegradation mechanisms depending on the characteristics of studied system. When dominant, photoreduction of BB1 to leuco-form (BB1-H), provides additional electron capture and consequently ensures decrease in h + − e − recombination rates, resulting in a false sensitizing effect.