Characteristic behavior of a cellulose acetate fiber cross-linked with amorphous TiO2

Generally, crystalline TiO2 and UV light are used to the decomposition of organics. However, we applied hybrid fibers consisting of amorphous TiO2 and cellulose acetate (CA) to wastewater treatment, with a dye and Cr(VI), under visible light irradiation. The prepared fiber (CA-amTiO(2) fiber) contained TiO2 in the amorphous state, which has not been well studied. It was found that this CA-amTiO(2) fiber could decompose the dye and reduce the highly toxic Cr(VI) under visible-light irradiation. Interestingly, the reduction abilities were much enhanced when amTiO(2) was used as a cross-linking agent for the CA fibers, compared with the case where amTiO(2) powder was just mixed in CA fibers. These abilities were valid only in cationic dye solutions containing Cr(VI), such as Methylene Blue and Rhodamine B. We discuss the possible mechanism at work in this system.