Photochemical treatment of industrial textile effluent containing reactive dyes.

Textile effluents are a result of the use of reactive dyes which present a strong environmental impact. These are substances of concern when conventional treatment processes are to be considered. This work refers to the study of post-treatment (purification) of the textile effluent originating from the use of reactive dyes (after biological treatment for activated sludge) through photocatalysis using TiO2 as semiconductor. The photocatalytic process was optimised according to the mass of the semiconductor (1.4 g l(-1)), flow of air (150 ml s(-1)), temperature (55 degrees C) and time of treatment (240 min). In the optimised conditions it was possible to verify high efficiency in the colour reduction (92%), COD (65%), BOD (40%) and TOC (29.3%). The study reached the conclusion that the photocatalytic process presents great potential as a method of post-treatment of effluents derived from the textile industry.