Photocatalytic performance of N-doped TiO2nano-SiO2-HY nanocomposites immobilized over cotton fabrics

Abstract

This work reports the synthesis of nanocomposite photocatalytic materials based on nitrogen-doped TiO2nano, SiO2 and different percentages of HY zeolite (0, 12, 25 and 50%). These materials were characterized by using Fourier transformed infrared spectroscopy, X-ray diffraction, N2 adsorptiondesorption, UV-vis diffuse reflectance spectroscopy and scanning electron microscopy. The nanocomposites, which presented an energy band gap of about 3.03 eV, were immobilized on cotton fabric and their self-cleaning properties were investigated by decolourization of rhodamine B (RhB) dye in aqueous solution under simulated solar irradiation. The fabrics coated with the photocatalysts, containing and not containing zeolites, showed the same RhB decolourization (about 95%) after 5 h, excluding the situation where a large amount of HY (50%) was used in the nanocomposites. However, results obtained from high performance liquid chromatography analysis depicted that in the presence of the HY zeolite a more effective RhB degradation was achieved. In fact, even after the use of five consecutive cycles, the RhB decolourization remained high (about 85%). Generally, the photodegradation of RhB solution in the presence of cotton fabrics functionalized with TiO2nano, TiO2nano-SiO2 and TiO2nano-SiO2-0.25 HY resulted in the formation of products that exhibited a similar cytotoxic effect when compared to the untreated RhB solution and subjected to the same tested concentrations and incubation times.