Using Nano-structured Photocatalyst To Degrade the Colour in Textile Dye Effluent Containing Auxiliary Agents

Linda Zou
Institute of Sustainability and Innovation, Victoria University

Yuncang Li
School of Engineering and Technology, Deakin University

Eric Hu
School of Engineering and Technology, Deakin University

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     Last modified: February 8, 2006

Abstract
Aqueous dye compounds can be effectively degraded by photocatalytic oxidation (PCO) process using nano structured titanium dioxide (TiO2) as a photocatalyst in the presence of ultraviolet (UV). The photocatatlytic decolouration of highly concentrated dye effluent was investigated using titanium dioxide (TiO2) as a photocatalyst in the presence of ultraviolet (UV). Colour degradation rates by the different types of TiO2 and UV source were detected. The experimental results indicated that dye effluent can be degraded efficiently at different levels for the different test condition such as particle size and forms of TiO2, UV-A and UV-B light. The photocatalytic oxidation (PCO) process using TiO2 pellets as a photocatalyst in the presence of ultraviolet-B can achieve the optimum rate of decolouration in our testing condition.

In dyeing process some auxiliary compounds, such as organic acids, fixing agents, surfactants, defoamers, oxidising/reducing agents and diluents, are added in the dyeing solution, which results in dye effluent with complex composition. This study investigated the photocatalytic degradation of wool dyeing wastes with different auxiliaries using TiO2 pellets as photocatalyst in aqueous solution under UV light. The experimental results indicated that eight dyeing wastes added with different auxiliaries could be degraded at different efficiencies. The decolouration degree of wool dyeing wastes would depend on both types of dyes and auxiliaries in the solutions. Investigations on the influence of two common auxiliary compounds, Cibaflow Cir and Albegal B in the PCO degradation of dyeing solutions were carried out. Results indicated that Colour removal ratio for Lanasol Blue CE with Cibaflow Cir can reach 78.0% comparing 28.9% colour removal ratio for Lanasol Blue CE with Albegal B after 3 hours PCO degradation. It means that the auxiliary, Albegal B have more influence than another auxiliary, Cibaflow Cir in the PCO degradation of dyeing solutions. This result will be beneficial for designing PCO process for degradations of dyeing effluent. However, more works on the influence of auxiliaries on PCO processes are needed to carry out in theory and practice.