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In this paper, we apply the temperature-programmed desorption (TPD) method combined with mass spectrometric (MS) analysis to characterize the hydrolysis products of Ti (SO4) 2 (SHy-NH) and TTIP (AHy-NH) with an NH3 aqueous solution, that can be vis-active photocatalysts when they are calcined at suitable temperatures in air. We find that H2O is the only product that exists below 100C. Beyond 100C, however, NH3 desorption begins and showsits maximum strength at approximately 200C. This desorption continues to near 450C ; we know this because NH+ (m/z 15) can still be detected beyond 400C. In the case of SHy-NH, desulfurization commences at approximately 400C, since SO2+ (m / z 64) , which cannot be removed by the washing process, is detected. Considering these results, the emergence of vis-activity during the process of hydrolysis product calcination appears to be concerned with the desorption of volatile species from the polycrystalline titanium oxide structure. We propose that this desorption leads to oxygen deficiency, as confirmed by XPS.

We designed and assembled a photocatalyst module for water treatment (referred to hereafter as module-I). The module consists of a Pyrex cylindrical tube into which a photocatalyst coated black light (P-BL) tube was inserted, and the admission port for water is attached tangentially to the curved surface of the P-BL tube. The decomposition-rate constant that we obtained by using a 3-ppm methylene blue aqueous solution showed a drastic increase when the fluid velocity exceeded 2 L/min. We think that the fluid velocity of 2 L/min is the turning point at which the flow pattern changes from a laminar flow to a spiral flow turning around the P-BL. We found that module-I is also effective for decomposition of 50 ppb or less concentration levels of dissolved substances such as 4,4'- (1-Methylethylidene)-bisphenol. From the results of decolorization experiments conducted with module-I in which we used 1 L of amber colored reclaimed water (RW) from a circulation toilet system as real waste fluid, we found that RW became transparent within 2-hours of operation at the fluid velocity of 6.1 L/min.