SYNTHESIS OF VISIBLE LIGHT ACTIVE PHOTOCATALYSTS AND THEIR APPLICATION IN PHOTOCATALYTIC DEGRADATION OF ORGANIC COMPOUNDS

Abstract

Nowadays, the presence of the various noxious compounds in water resources becomes a worldwide sensation in regard with the exploitation of progressive and field-applicable water treatment technology. Titanium dioxide (TiO2) is the most effective photocatalyst for decomposition of organic contaminants in water resources due to its high photoactivity for the production of hydroxyl radical, low cost, chemical inertness, and low toxicity. However, TiO2 is only activated by ultraviolet light. Accordingly, many attempts have been made to extend the available range to the visible-light area by metal and non-metal doping, dye photosensitization and so on. In the first part of study, 2-ethylimidazole-TiO2 (N-doped TiO2) photocatalyst was synthesized by a simple method by 2-ethylimidazole as the specific nitrogen source, and its photocatalytic activity was examined for degradation of microcystin-LR under visible light irradiation because harmful cyanobacterial toxins (e.g., microcystins) have raised concerns about the safety of drinking water resources. The synthesized photocatalyst was compared to other N-doped TiO2 materials reported in previous studies for the photocatalytic activity. In the second part of study, Co-H2O2-TiO2 can be synthesized using the precursor, TTIP (Titanium Tetraisopropoxide), and hydrogen peroxide. Additionally, the efficiency of H2O2-TiO2 in visible light rage was experimentally confirmed through the previous study. In this study, a simple cobalt doping method was utilized for increasing the photoactivity of H2O2-TiO2. Then, decomposition efficiency was checked by applying various contaminants. Finally, the mechanism of photocatalyst was proposed with an explanatory diagram.