Abstrakt

The main aim of this dissertation was the transfer of photocatalytical laboratory scale experiments to semi-technical scale. Preliminary experiments of the purification of organic chlorine-loaded waters and the immobilization of photocatalysts were performed, which yielded the research back to the roots of synthesis. The first applied research was carried out on treatment of recreational water. Several light sources, particularly sun light, mercury-medium-pressure lamp, and UV-LEDs, were applied. It was shown that the amount of organic compounds can be decreased by photocatalysis. However, the irradiation of samples by mercury-medium-pressure lamp was superior to all used light sources, since photolytic reactions accounted for majority of compound decomposition. Furthermore, the applicability of photocatalysis for disinfection was evaluated. Experiments were conducted with the chlorine resistant parasite Cryptosporidium. No conglomerates were formed between Cryptosporidium oocysts and P25 TiO2 particles, which impedes the OH radical attack and makes the photocatalytical disinfection of Cryptosporidium not suitable. Particular emphasis was placed on immobilization of TiO2 photocatalyst onto glass beads by sol-gel and dip-coating method. Contrary to other scientific research the durability of immobilization was investigated. The photocatalyst was not firmly bound to the support and up to 50% of the coating was lost during the photocatalytic treatment. These results led to the investigation of cathodic deposition and occlusion of TiO2. Cathodic deposition of photocatalysts, especially TiO2, was proposed in the literature, but only a few researchers investigated the photocatalytic activity of cathodic deposited films. Furthermore, electrochemical oxide deposition was mainly investigated for conductive glass working electrodes. In this dissertation, I succeeded to deposit TiO2 onto stainless steel electrode. The photocatalytic activity of deposited TiO2 was found to be low in comparison to commercially available P25 photocatalyst. Nevertheless, it was shown that the electrochemical occlusion of the P25 photocatalyst particles into the TiO2 film was possible and that the photocatalytic activity of the film could be increased.

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