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In this study, the V-doped TiO2 was synthesized by sol-gel method and we evaluate the photocatalytic degrading efficiency of V-TiO2 complexes on azo dye wastewater under irradiation with visible light (λ= 419 nm). The results showed that the Anatase structure and nano size of V-TiO2 complexs were formed and they had better photo-response to visible light than pure TiO2. The efficiency of decoloriztion or destruction efficiency was less than 6 % using TiO2 alone but efficiency of 0.10VT-I was up to 90% after irradiated with visible light for 240 min. These evidences also reveal that the system of V-TiO2 complexes can directly utilize the sunlight and can be used to treat organic pollutants in the practical wastewate treatment factories.

The use of TiO2 as photocatalyst to degrade the organic compounds is an effective method of oxidation process and has been widely studied in environmental engineering. However, TiO2 absorbed the UV light which is only small part of sunlight reaching earth surface to activate photocatalytic procedure is a major disadvantage. Therefore, studies on the development of new TiO2 that its photocatalytic activity can be activated by visible light which is the major part of sunlight will be valuable for field application. In this study, we evaluate the photocatalytic degrading efficiency of porphyrins/TiO2 complexes on the organic pollutants under irradiation with visible light (λ= 419 nm). The results showed that the photodecomposition efficiency of methylene blue were up to 95% and 90% respectively after using NiTPP/TiO2 and ZnTPP/TiO2 irradiated with visible light for 6 h. These evidences reveal that the system of porphyrin/TiO2 complexes has significantly high efficiency of photocatalytic degradation under visible light irradiation.

In this study, titanium dioxide thin film was prepared using the modified chemical vapor deposition. The parameters employed to control the preparation of the catalyst include the temperature of water bath, the Ti(OC3H7)4/H2O ratio, the flow rate of carrier gas, the oxidation temperature, the oxidation time, the calcination temperature, the rotating speed of furnace, and the speed of geared motor. The orthogonal arrays in the design of experimental method proposed by Taguchi were adopted to conduct the multiple-factor experiment. The conversion rate of salicylic acid in the aqueous or heterogeneous phase photocatalysis experiment was employed to identify the optimal conditions for assembly. The results indicated that a higher conversion ratio of the organic substance could be achieved under catalytic oxidation temperature of 400°C, calcination temperature of 550°C, and spraying speed of 30 rpm and the optimal experimental conditions obtained in this study were irradiation with intensity of 2.9 mW cm-2 on salicylic acid at concentration of 250 mg L-1 by both agitation and aeration processes (dissolved oxygen level = 8.2mg O2 L-1) at pH 5, which could achieve optimal hydroxyl radical yield of 5.1 ×10-17 M.

A microwave/Fe3O4 catalytic system was proposed for treatment of volatile organic carbons (VOCs). This system comprises a household microwave oven modified as the reaction chamber, which was fitted with a vertical, cylindrical quartz reactor comprising a catalytic packed column filled with granular Fe3O4, a microwave catalyst of iron (II, III) oxide. Experimental results showed that the destruction and removal efficiency (DRE) of toluene by microwave alone was close to zero, but with the microwave/Fe3O4 system, the temperature of the catalytic packed column increased rapidly and reached thermal balance within 10-15 min. Analysis of the rear gas after combustion showed that most of the toluene was thermal oxidized into CO2 and H2O. The successful application of the proposed microwave/Fe3O4 system to thermal destruction of toluene promises a new technology for treatment of VOCs.