Use of dimensionally stable anodes for the electrochemical treatment of textile wastewaters [articol]

Abstract

This study deals with the treatment of textile wastewaters containing azo dyes by electrochemical oxidation at dimensionally stable anodes (DSA). Two anodic compositions were used: Ti/Ru0.3Ti0.7O2 and Ti/Ir0.3Ti0.7O2. The characteristics of the textile wastewater were: pH=8.3, Cl-=653 mg/L, and the value of wavelength that corresponded to tha maximum of absorbance of textile wastewater in the visible region, A595 nm = 1.35 (dil.=1:2.5). Experiments were carried out at applied current densities of 25, 50and 75 A/m2 and various electrolysis times: 5, 10, 15, 30 şi 60 minutes. UV-VIS spectra of the electrolysed solutions were recorded and colour removal efficiency was determined. The degradation of dyes by electrochemical oxidation was also assesed by the increase of absorbance at 253 nm (A253). For both anodic compositions, colour removal efficiency was 100%. On the other hand, the formation of chlorinated organic compounds during the electrochemical treatment of textile wastewaters is a disadvantage of this method.