Abstract: A photocatalyst-supporting body comprises a substrate, a porous layer fixedly disposed on at least one surface of the substrate, and a semiconductor photocatalyst layer deposited on the surface of the porous layer. The porous layer is made of fine particles or porous nonwoven metal fabric. Since the semiconductor photocatalyst is bound to the substrate through the porous layer, the area of the photocatalytic surface is increased and the contaminants in a fluid flow being treated adequately contact the photocatalytic surface thereby to enhance the photocatalytic efficiency. The photocatalytic efficiency is further improved by making the porous layer dense (rough) in the vicinity of the surface of the substrate and rough (dense) with increasing distance from the surface of the substrate.

Abstract: A three-dimensional, photocatalytic filter apparatus is constituted by (a) a flow path means through which a fluid stream containing pollutants passes; (b) a plurality of porous filter plates each carrying a photocatalyst for decomposing the pollutants; (c) a light source; and (d) at least one support member for arranging each porous filter plate in a path of the fluid stream in the flow path means, at such a three-dimensional position that each porous filter plate is inclined relative to both the fluid stream and the light source, to achieve sufficient contact with the pollutants and sufficient exposure to the light source.

Abstract: A roll and process for producing same are disclosed. This process includes the steps of: horizontally placing a core body made of a cast steel or a steel based Adamite containing from 0.5 to 2.5 %C, said core body having one or more circumferential grooves; feeding a consumable electrode wire into said groove or grooves, while rotating said core body, to thereby obtain according to an electro-slag welding process a deposited metal or metals filled in said groove or grooves, said deposited metal or metals containing from 1.5 to 2.5%C, from 0.2 to 1.0% Si, from 0.5 to 1.0% Mn, from 0.5 to 3.0 % Cr, from 0.2 to 3.0 % Mo, from 0 to 2.0 V, the balance being essentially Fe, and inevitable impurities; subjecting same to heat treatment at a temperature ranging from 500.degree. C to 700.degree.