Efficiency of Heterogeneous Photocatalysis with Titanium Dioxide in the Alteration of Physicochemical and Toxicological Parameters of Textile Effluent

Abstract

Textile industry is responsible for producing a large amount of effluent. The objective of the present study was to treat the raw effluent of a textile manufacturer through heterogeneous photocatalysis (TiO2/UVsolar). Four types of effluents were evaluated: raw (RE), treated by the manufacturer (MTE), and exposed to photocatalysis in the presence (PTETi) and absence (PTE) of titanium dioxide (TiO2). They were evaluated for physical, chemical, and toxicological parameters. In regard to dissolved oxygen (DO) contents, MTE, PTETi, and PTE effluents increased values when compared with RE effluent. Color degradation was more efficient by MTE effluent, but the chemical oxygen demand (COD) values of the treated effluents were not in accordance with Brazilian norms. Besides that, the toxicity test with Allium cepa L. shows cytotoxicity by MTE (24 and 48 h) effluent. PTETi and PTE (24 h) effluents did not show cytotoxicity, but PTETi-48 h showed a significant decrease in mitotic index. The immobility/mortality test with Artemia salina L. showed toxicity of the RE and MTE effluents in concentrations of 100% and 50%. In the case of the phototreated effluents, there was only toxicity in the concentration of 100%. Thus, so generally, photocatalytic treatments were more efficient than the treatment applied by the manufacturer; however, it is necessary to improve a new stage in the treatment.