In this study, a flat-type photocatalytic reactor is applied under solar irradiation for simultaneous treatment of target pollutants: reduction of Cr(VI) to Cr(III) and oxidation of EDCs (BPA, EE2, E2). An immobilized type of photocatalyst was fabricated to have self-grown nanotubes on its surface in order to overcome limitations of powdery photocatalyst. Moreover, Ti mesh form was chosen as substrate and modified to have both larger surface area and photocatalyst content. Ti mesh was anodized at 50V and 25°C for 30min in the mixed electrolytes (NH4F-H2O-C2H6O2) and annealed at 450°C for 2 hours in ambient oxygen to have anatase structure. Surface characterization was done with SEM and XRD methodologies. Fabricated NTT was applied to water treatment, and coexisting Cr(VI) and organics (EDCs) enhanced each other's reactions by scavenging holes and electrons and thus impeding recombination. Also, several experiments were conducted outdoor under direct sunlight and it was observed that both solar-tracking and applying modified photocatalyst were proven to enhance reaction efficiency.

In this study, flat-type photocatalytic reaction system is applied to reduce toxic hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)) in aqueous solution under UV irradiation. To overcome the limitation of conventional photocatalysis, a novel approach toward photocatalytic system for reduction of hexavalent chromium including nanotubular TiO2 (NTT) on two kinds of titanium substrates (foil and mesh) were established. In addition, modified Ti substrates were prepared by bending treatment to increase reaction efficiency of Cr(VI) in the flat-type photocatalytic reactor. For the fabrication of NTT on Ti substrates, Ti foil and mesh was anodized with mixed electrolytes (NH4F-H2O-C2H6O2) and then annealed in ambient oxygen. The prepared NTT arrays were uniformly grown on two Ti substrates and surface property measurements were performed through SEM and XRD. Hydraulic retention time(HRT) and substrate type were significantly affected the Cr(VI) reduction. Hence, the photocatalytic Cr(VI) reduction was observed to be highest up to 95% at bended(modified) Ti mesh and lowest HRT. Especially, Ti mesh was more effective as NTT substrate in this research.

One of the best solutions for the deficiency of clean water, especially for developing countries, is rainwater disinfection. In the past decades a lot of studies have been made to develop photocatalytic processes using TiO2 determining the performance on their surface oriented photocatalysis. However, most of these researches failed to consider the economical aspect as well as the effectiveness on the disinfection to antibiotic resistance genes. On the other hand, due to the issues of climate change and increased impermeable layer in urban area, flooding prevention is the best solution in water management systems. To remedy these two problems, a roof-harvested rainwater storage system was designed. In addition, a breakthrough technique using a solar simulator with self-rotating TiO2 nanotubes, to apply a photocatalytic system in disinfecting storage rainwater harvested from roof, was established. Roof-harvested storage rainwater was analysed for TN, TP, SS and COD. Aside from these parameters, Escherichia coli (with multidrug resistant pB10 plasmid) was added to the sample. Samples were injected to the self-rotating TiO2 nanotube reactor system with exposure time of 0 to 360 min and 7 different setups. Results show that the developed system has increased disinfection properties compared to negative samples, though the presence of antibiotic resistant bacteria.