Decolorization of textile wastewater by electrooxidation process using different anode materials: Statistical optimization.

The presence of reactive dyes in textile wastewater is a serious environmental concern due to their associated mutagenic and carcinogenic effects. The present study aims to analyze the effect of different anodic materials on the decolorization of a real textile wastewater effluent. For this purpose, four different anodic materials-TiO 2 -coated platine, TiO 2 -coated ruthenium dioxide (RuO 2 ) (viz., RuO 2 ), titanium dioxide (TiO 2 ), and graphite-were connected, respectively, to titanium dioxide (TiO 2 ) used as a cathode electrode. Color and cost optimization studies were performed using the response surface methodology and the Box-Behnken experimental design (BBD). According to ANOVA results, the R 2 values for Pt/TiO 2 , RuO 2 /TiO 2 , TiO 2 /TiO 2 , and graphite/TiO 2 electrode pairs were found to be 97.4%, 93.8%, 92.44%, and 92.2%, respectively, indicating a good compatibility as it is close to one. The results show that color removal efficiencies at the optimal conditions were 86.3%, 90.8%, 91.5%, and 93.6% for Pt/TiO 2 , graphite/TiO 2 , TiO 2 /TiO 2 , and RuO 2 /TiO 2 , respectively. Furthermore, energy consumption cost at the optimum conditions was also evaluated, and the results were as follows: Pt/TiO 2 (0.95 €/m 3 ), graphite/TiO 2 (0.74 €/m 3 ), TiO 2 /TiO 2 (0.31 €/m 3 ), and RuO 2 /TiO 2 (0.26 €/m 3 ). Consequently, this research paper shows that all of the tested anodic materials give satisfactory color removal efficiencies higher than 86%. When energy consumption and color removal are considered together, the use of TiO 2 /TiO 2 and RuO 2 /TiO 2 pairs would be preferred. PRACTITIONER POINTS: Anodic contribution was investigated for decolorization of textile wastewater by electrooxidation process. Graphite, TiO 2 -coated Pt, TiO 2 -coated RuO 2 , and TiO 2 were used as anode materials. Highest color removal with lowest energy consumption was achieved with TiO 2 -coated RuO 2 anode material (93.6%).