Ultraviolet photocatalysis

Kiwi, J., Morrison, C. 1984. Heterogeneous photocatalysis-dynamics of charge-transfer in lithium-doped anatase-based catalyst powders with enhanced water photocleavage under ultraviolet-irradiation. J Phys Chem 88 6146-6152. 

Venkatadri, R. and Peters, R.W., Chemical oxidation technologies ultraviolet light/ hydrogen peroxide, Fenton s reagent, and titanium dioxide-assisted photocatalysis, Hazardous Waste Hazardous Mater., 10, 107-149, 1993. 

From these results and others from UV-vis absorption spectroscopy and differential pulse polarography (data not shown), Garbin et al. (2007) concluded that HS can act as photocatalyst to pesticide photolysis in aqueous solution only for specific ranges of concentration (as seen in Figure 16.12), which in turn depended on the HS and pesticide chemical characteristics. Under ultraviolet and visible radiation, this photocatalysis is based on photogeneration of -OH radicals, and the susceptibility of pesticide molecules to -OH attacks defines the efficiency of the photocatalysis. 

Nano Titania is one of the earliest nano materials to be applied commercially. It has a number of superior properties, such as super strong scattering and anti-ultraviolet capabilities, special electromagnetism and catalysis characteristics, especially the photocatalysis ability decomposing microbes, and also extremely high surface activity... 

Keywords Photochemical Advanced Oxidation Technologies Vacuum ultraviolet Ozonation Direct photolysis Photo-Fenton Photo-ferrioxalate Photocatalysis... 

Calvert 124), sintered cuprous oxide present as a thin layer on bulk copper also shows photocatalysis of CO oxidation when irradiated with ultraviolet light at 25°. These authors observed that the addition of sulfur or antimony in solid solution, which increased the conductivity of the oxide, decreased the photoeffect, but the reason for this particular choice of dopents is obscure. 

Photocatalysis A catalytic reaction triggered or enhanced by illuminating the system with visible or ultraviolet irradiation. This reaction involves normally the electronic excitation of the catalyst via the absorption of photons and an interfacial charge transfer to an adsorbed species. Typically, the photocatalyst is not consumed in the reaction. 

In environmental terms, nanocomposites can be used as adsorbent materials or photocatalytics in the process of removing metallic ions and/or organic compounds in the treatment of residual water. Nanocomposites have received considerable attention in the scientific community in the last few years because they present properties comparable to other conventional materials and low-cost treatment processes. In the case of photocatalysis, nanocomposites present photocatalytic properties, improved because of the extension of the ultraviolet absorption band and fomented by the inherent properties of each of the materials present. 

With photocatalysis the main problems encountered in the previously examined applications of PVRs are avoided. It is also worth noting that (i) the coupling of photocatalysis with the pervaporation process allows for a complementary exploitation of the solar spectrum. In fact, photocatalysis is normally only able to use its ultraviolet component, while the remaining thermal part of the spectrum can be utilized to heat the fluid and to evaporate the permeate (ii) photocatalysis and pervaporation have common operative conditions liquid solutions (often aqueous solutions), low concentrations of the reactants and consequently of the products, low temperature and atmospheric pressure and (iii) once the type of light source is chosen, photocatalysis is a modular process like pervaporation. Therefore the integration of the two processes is straightforward and advantageous. 

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