Removal of reactive azo dye using platinum-coated titanium electrodes with the electro-oxidation process

Abstract

The removal of Drimaren Orange HF 2GL (DOHF2GL) azo dye from aqueous solutions was researched using platinum-coated titanium electrodes with the electro-oxidation process. The effects of electrolyte type, NaCl concentration, current density, initial dye concentration, pH, and solution temperature on dye removal were investigated. The maximum removal efficiency was determined as 98.7% at the end of 120 min for electrolyte concentration 4 g/L NaCl, current density 1.74 mA/ cm2, temperature 20°C, pH 7, and dye concentration of 100 mg/L. When NaCl was used as an electrolyte, there was lower energy consumption and higher dye removal compared to NaNO3 and Na2 SO4 . With the increase in NaCl concentration, the cell potential reduced, and the treatment efficiency was determined to increase. The current density was the most important param-eter affecting dye removal rate and energy consumption was determined to be largely linked to the current density applied. The dye removal efficiencies increased with the applied current density and electrolyte concentration and decreased with the increase in initial dye concentration. Experimental data under different reaction conditions were used to determine that the dye removal kinetics followed pseudo-first-order kinetics. Fourier transform infrared spectroscopy (FTIR) studies were performed to assess the degradation of dye with the electro-oxidation process.