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.

This work is devoted to study the photocatalytic ability of cotton textiles functionalized with SiO2-TiO2 and SiO2-TiO2-HY composites to degrade a dye molecule. Coatings were prepared by sol-gel method and calcined at different temperatures in a range of 400–750 °C. FTIR confirmed the existence of SiOTi bounds and the band located in the region between 570 and 600 cm−1 was used to calculate the framework Si/Al ratio of HY in the SiO2-TiO2-HY composites. XRD confirmed the presence of nanosized TiO2 (anatase phase) in all calcined composites. Nitrogen adsorption isotherms showed a decrease in surface area and pore volume for higher calcination temperature. A simple mechanical process was used to impregnate the different composites on the cotton substrates. The photocatalytic activity of cotton textiles functionalized with SiO2-TiO2 and SiO2-TiO2-HY composites was tested via the degradation of Rhodamine B (RhB) dye under similar solar irradiation. The best catalytic performance was achieved with the SiO2-TiO2 and SiO2-TiO2-HY composites subjected to a calcination treatment at 400 °C, whereas SiO2-TiO2 presented a decolourization and mineralization around 94% and 89%, respectively, after 2 h of irradiation. Furthermore, the products of RhB degradation were analysed and identified by using HPLC-ESI–MS and ion chromatography techniques and a photocatalytic mechanism was proposed.