Immobilization of TiO2 on pumice stone for the photocatalytic degradation of dyes and dye industry pollutants

An easy method is proposed to immobilize TiO2 for photocatalytic transformations of organic pollutants in aqueous solution. It consists of impregnation of pumice stone pellets with commercially available TiO2. Pumice stone is a soft material, but this disadvantage can be eliminated by fixing pellets on a hard surface (cement or polycarbonate) and using a thin-film fixed bed reactor. Examples of application are given with 3-nitrobenzenesulfonic acid (3-NBSA), Acid Orange-7 (AO-7, a dye) and real wastewaters collected after biological treatment.