Electrochemical Systems for Degradation of Colored Compounds from Textile Industry Effluent

Dyes are the compounds used to impart color in various industries having an immense negative effect on the environmental and human wellness when it is discharged without adopting adequate treatment. In this research, oxidation of acidic (congo red, CR) and basic dye (crystal violet, CV) from synthetic effluent using different electro-chemical techniques i.e. Fenton (FT) and electro-Fenton processes (EF) has been carried out. Meanwhile, the consequence of operational parameters viz contacts time (0–180 min), dye concentration (25–300 mg/L), pH (3–11), voltage (5–25 V), FeSO₄ + H₂O₂ dosage (100 + 50 − 500 + 250 mg/L), number of electrodes (2–6), electrode spacing (1–2 cm) and electrode combination (Fe-Al–Fe-Al and Al–Fe-Al–Fe) for dye degradation were examined. On the other hand, treatment of real-time textile effluent was investigated at optimum operating conditions obtained. First-order and second-order kinetic models were used to determine rate constants for degradation of dye compounds from effluents. From results, it was observed that EF process with Fe electrodes showed maximum dye degradation of 98.24% and 90.53% for CR and CV dye, respectively at natural pH. The removal CR was greater than the CV dye at optimum operating conditions i.e. 60 min, 20 V with four Fe electrodes at 1cm electrode distance. Subsequently, treatment of real-time textile wastewater performed at optimum conditions showed removal of ~97% with Fe-Al–Fe-Al electrodes combination in comparison with Fe (51%), Al (82%), and Al–Fe-Al–Fe (94%) electrodes. The removal of both dyes using Fe and Al electrodes from synthetic wastewater followed second-order kinetics. Meanwhile, kinetic constants for treatment of real-time textile effluent were found to be 0.016 min⁻¹ for Fe electrodes, 0.013 min⁻¹ for Al electrodes, 0.009 min⁻¹ for Fe-Al–Fe-Al and 0.007 min⁻¹ for Al–Fe-Al–Fe electrodes. While the energy consumption and electrical energy order were calculated, it turned out that Fe electrodes utilized less energy and had better electrical energy order (EEO) than Fe electrodes for both CR and CV dyes. In conclusion, EF technique can be effectively adopted for effective degradation of dyes from industrial effluents.