Photodecomposition in aqueous solution of 3,5-dichloro-N-(3-methyl-1-butyn-3-yl)benzamide, whose popular name is propyzamide, was investigated using naked TiO 2 and TiO 2 -loaded adsorbent supports as photocatalysts. The adsorbent supports used were zeolite (mordenite), silica, and activated carbon. The use of adsorbent supports was found to enhance the rate of mineralization of propyzamide and to reduce the concentration of solution-phase intermediates. The experimental results suggest that the adsorbent support concentrates a target substrate of low solutionphase concentration on its surface, providing the substrate-rich environment at the adsorbent/TiO 2 interface. This concentration effect results in an enhanced rate of propyzamide mineralization. The intermediates are also retained on the adsorbent support and subsequently decomposed, thereby reducing the concentration of possibly toxic intermediates in the bulk solution. ES950483K X Abstract published in Advance ACS Abstracts, February 15, 1996.FIGURE 7. Distribution of intermediates detected by GC/MS analysis after irradiation for 15 min. The open and hatched parts represent the fraction of intermediates dissolved in the solution phase and adsorbed on the photocatalyst, respectively. The photocatalyst used was naked TiO2 (a) and 70 wt % TiO2/AC (b). For experimental conditions, see the caption of Figure 2. FIGURE 8. Reaction mode of photoinduced mineralization of propyzamide over naked TiO2 (a) and TiO2-loaded adsorbent (b).

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In the ceramic industry, ceramic particles remain on a mold surface due to which the mold requires frequent cleaning during press molding, reducing productivity. Surface texturing and tetrahedral amorphous carbon (ta-C) coatings are well-known surface-energy controllable treatments developed for low adhesion, low friction, and high wear resistance. In the present paper, we demonstrate the effect of reducing ceramic residues using nanotexturing, ta-C coatings, and their combination. We compare two surface morphologies (i.e., 770 nm pitch nanotexturing and flat) and five materials (i.e., nonhardened steel, hardened steel, ta-C, and two types of nitrogen-doped ta-C (ta-CNx). Molding test results show that the ta-C coating on flat surfaces with the highest hardness of 30 GPa shows the lowest residual amount of 5.9 μg for Al2O3 ceramic particles. The amount is 82% less than that of the nonhardened steel. The ta-CNx20, made with a nitrogen flow rate of 20 sccm, shows the lowest residual amount of 234 μg for SiO2 ceramic particles, which is 81% less than that of the nontextured ta-CNx20. In conclusion, we provide design guidelines for nanotextured mold surfaces including the texturing pitch should be small enough for ceramic particles; the mold surface should be sufficiently hard; the lower the surface energy per unit area, the less residues of ceramic particles.

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