(JP7148434-A)      Photocatalyst body (pref. average grain dia.; 0.1-100 mm) comprises photosemiconductor particles (pref. titanium oxide) adhered on the surface and vacant pore wall of inorganic porous particle, pref. natural mineral.    Pref. the photocatalyst body is arranged at the place in which the body is contacted with water. Then, light contg. UV light is irradiated to the photocatalyst body, and water is purified.    USE/ADVANTAGE -   The photocatalyst body may be used for photocatalytic reactions, for purifying water. The photocatalyst body has stable photocatalytic function for a long period. It is easy to separate from a treated water system.    (JP2613179-B2)      Photocatalyst comprises inorganic porous particles (I) with photosemiconductor particles (II) and opt. microorganisms having water purificn. activity deposited on at least part of the surfaces, and at least part of the walls of the pores of (I).    USE -   The photocatalyst is used for purifying water by irradiation with light contg. UV radiation when in contact with water. The catalyst may be conveniently used in processes to kill harmful organisms such as algae, fungi and bacteria, decompose contaminants and deodorise and decolourise H2O.    ADVANTAGE -   The photocatalysts are stable for extended periods and may be used for a variety of photocatalytic reactions. The catalyst is easily sepd. from treated H2O.    (EP634363-B1)      Photocatalyst comprises inorganic porous particles (I) with photosemiconductor particles (II) and opt. microorganisms having water purificn. activity deposited on at least part of the surfaces, and at least part of the walls of the pores of (I).    USE -   The photocatalyst is used for purifying water by irradiation with light contg. UV radiation when in contact with water. The catalyst may be conveniently used in processes to kill harmful organisms such as algae, fungi and bacteria, decompose contaminants and deodorise and decolourise H2O.    ADVANTAGE -   The photocatalysts are stable for extended periods and may be used for a variety of photocatalytic reactions. The catalyst is easily sepd. from treated H2O.