Combining electrochemistry and UV for the simultaneous wastewater decolorization and reduction of salinity

Abstract

Textile dyeing processes with reactive dyes consume high amount of water and generate wastewater containing residual dyes and salts. In this work, wastewater generated by a textile industry was treated by means of electrochemical techniques combined with ultraviolet irradiation. Five industrial wastewaters were collected in a textile mill and were treated at 10 A in an electrochemical cell. Full color removal was obtained after 10 minutes of treatment. The optimization of the electrochemical treatment was performed in order to select the most suitable conditions. Subsequently the decolorized effluents, which still contain salts, were irradiated with UV light to remove residual oxidants and were reconstituted for its reuse. This procedure enabled to reuse 70% water and 64% salt in the dyeing process. The chromatic coordinates of these dyed samples were evaluated with respect to reference ones. In all cases, samples dyed with the reused effluents showed colour differences into acceptance limit of the textile industry (DECMC(2:1) values lower than 1).

Keywords

• industrial textile wastewater
• reactive dye effluents
• effluent reuse
• salt reuse
• dyeing process
• electrochemical treatment
• UV irradiation