Removal of organic pollutants by coprecipitation with metallic hydroxides and photochemical treatment

Effluents from textile, and paper and cellulose industries were treated combining the precipitation of Zn (II), Fe (III) and Zr (IV) hydroxides with photochemical treatment with UV light. By using zinc hydroxide precipitation, colour, total phenols and total organic carbon are greatly reduced in effluents from the paper industry. With further irradiation in the presence of the precipitate, colour is almost completely reduced and the phenol concentrations are reduced to < 20% of their original value without additional reduction of organic carbon concentration. Irradiation permits an additional decrease of the organic matter adsorbed on to the precipitate surface. The results for textile effluent are not satisfactory because the decolorization obtained by the ferric hydroxide precipitation is accompanied by a considerable generation of phenolic forms when the system is submitted to irradiation.18446146