Enhanced Photocatalytic Activity of TiO2 Codoped with N and Cu for Degradation of Rhodamine B

Abstract

In textile industries, different types of dyes are used widely. Widespread use of these dyes causes surface and ground water contamination. This contaminated water is harmful for the human beings and other organisms as well. Therefore, treatment of this contaminated water is important. These dyes can be removed from wastewater by using biodegradation but this method doesn’t remove these dyes completely. Photodegradation has proved really successful in converting these toxic compounds to non-toxic or less toxic compounds e.g. CO2 and H2O. This work emphasizes on photodegradation of rhodamine B using TiO2 based photocatalysts. In this work, nanoparticles of pure and doped TiO2 were synthesized by sol-gel method. For the synthesis of TiO2 nanoparticles, TTIP (Titanium tetraisopropoxide), 2-propanaol and distilled water were used. Whereas, for nitrogen and copper doping, urea and copper acetate were used along with TTIP, 2-propanol and distilled water. The samples were characterized by SEM, EDX, XRD, UV-vis DRS and FTIR. Band gap of doped catalysts were found to be low as compared to pure TiO2 which makes doped photocatalysts more suitable for photocatalytic degradation. The photocatalytic activity of N/Cu-TiO2 catalyst was higher than pure and nitrogen doped TiO2 for degradation of rhodamine B. Highest degradation efficiency was achieved with 1% Cu-TiO2 among all copper doped catalysts (0.1% Cu-TiO2, 0.25% Cu- TiO2, 0.5% Cu-TiO2 and 0.75% Cu-TiO2) that was 88%. So, it was further codoped with nitrogen and checked its efficiency for degradation of rhodamine B. Results reveal that the codoped catalyst gives better results than its precursor i.e. 96% degradation was achieved. Different conditions of degradation experiments were optimized. The best catalytic activity of the photocatalyst was achieved at 50 mg catalyst dosage, 10 ppm concentration of the analyte and pH 4. Reusability of the photocatalyst was checked for up to 4 runs and it was observed to decrease from 96% to 84%.