Evaluation of ZnO, TiO2 and supported ZnO on the photoassisted remediation of black liquor, cellulose and textile mill effluents

• Published in: Chemosphere (Oxford) 1998-04, Vol.36 (9), p.2119-2133
• Main Authors: Peralta-Zamora, P, Gomes de Moraes, S, Pelegrini, R, Freire, M. Jr, Reyes, J, Mansilla, H, Duran, N
• Format: Article
• Language: English
• Subjects: Applied sciences; color; Exact sciences and technology; industrial effluents; Industrial wastewaters; oxidation; phenols; photolysis; Pollution; pulp and paper mill effluents; removal; sulfate liquor; textile industry; titanium dioxide; ultraviolet radiation; wastewater treatment; Wastewaters; Water treatment and pollution; zinc oxide
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/S0045-6535(97)10074-1

The use of titanium dioxide and zinc oxide as semiconductor metallic oxides in the photocatalytic treatment of effluents derived from the Kraft wood pulping process was already documented. The application of these compounds to the remediation of effluent derived from textile and pulp and paper mills was evaluated. Data showed that when Kraft and textile effluents were submitted to ultra-violet (UV) radiation in the presence of free titanium dioxide zinc oxide or zinc oxide supported on silica gel the colour faded progressively so that a substantial decolorization was achieved. Accompanying this process was a reduction in the concentration of total phenols in the black liquor and final effluents. Conversely an increase in phenol concentration accompanied the early stages of photocatalysis of the textile effluent. Degradation of chemical species present in the effluent was demonstrated by HPLC analysis and mineralization up to 50 per cent was confirmed by determination of total organic carbon. The toxicity of all effluents was reduced by about 50 per cent. Decolorization was not observed in the absence of photocatalysts. There are 35 references.