Abstract:
Industrialization around the world increases wastewater discharge, causing
environmental issues with great concern. Wastewater treatment and management is the
major problem in the textile industry. Although there are many traditional methods to
remove color from wastewater, the electrochemical process could be a promising
alternative for efficient and eco-friendly treatment. In this study, Rhodamine B (Rh-B)
dye was used as a model textile dye to determine the optimum conditions in the
electrolytical removal with electrochemical cell. In the presence of the chlorinated
electrolyte, the efficacy of the dye degradation is described by the electro-oxidation that
leads to the generation of strong oxidizing chlorine active species besides the graphite
anode. On the copper cathode, reduction of water activates as the cathodic reaction. The
effect of concentration of electrolyte (NaCl), pH, current density, temperature, Rh-B dye
concentration and contact time on the degradation of dye were examined by assessing the
color removal efficiency, Chemical Oxygen Demand (COD) under the optimized
conditions. It was observed that highest color removal efficiencies were reached at 30 0C,
pH 7.0 at the 0.075 M NaCl concentration, 80 mA cm-2 current density. And these
optimized conditions were suitable for below 100 ppm of Rh-B dye concentration. The
91.62±0.14% color removal efficiency after 60 minutes of electrolysis for 50 ppm dye
solution and 77.07±0.15% of color removal efficiency after 90 minutes for 100 ppm dye
were achieved at the optimal conditions. After 180 minutes of experiment, 52.70±4.42%
and 50.65±2.13% of COD removal efficiencies were achieved for 50 ppm and 100 ppm
of Rh-B dye respectively. Under the optimized conditions, the percentage weight loss
values of graphite (0.97±0.01%) and copper (0.94±0.73%) electrodes were obtained for
50 ppm dye treatment. The electro-oxidation was found to be highly effective in the
treatment of textile effluents containing Rh-B dye, without forming any sludge.
