Electrooxidation using SnO 2 –RuO 2 –IrO 2 |Ti and IrO 2 –Ta 2 O 5 |Ti anodes as tertiary treatment of oil refinery effluent

• Published in: Applied Research 2023-10
• Main Authors: Treviño‐Reséndez, José, Medel, Alejandro, Cárdenas, Jesús, Meas, Yunny
• Format: Article
• Language: English
• ISSN: 2702-4288; 2702-4288
• DOI: 10.1002/appl.202300038

In the present work, treatability studies were carried out with oil refinery wastewater (effluent from the secondary treatment) using electrooxidation (EO) process employing two mixed oxide anodes: SnO 2 –RuO 2 –IrO 2 |Ti and IrO 2 –Ta 2 O 5 |Ti. Both electrodes' performance were compared by their capacity to generate active chlorine in a synthetic solution and organic matter mineralization of a sample with an average phenol (C 6 H 6 O) concentration of 100 mg L −1 . Before degradation experiments, surface analysis, and linear sweep voltammetry tests were performed. SnO 2 –RuO 2 –IrO 2 |Ti anode yielded higher active chlorine, reaching an average concentration of 340 mg L −1 at 90 min of electrolysis and 25 mA cm −2 . On the other hand, IrO 2 –Ta 2 O 5 |Ti anode only generated an average concentration of 200 mg L −1 at 90 min and 40 mA cm −2 . Regarding the degradation experiments, SnO 2 –RuO 2 –IrO 2 |Ti anode showed the highest dissolved organic carbon removal, ranging from 26% to 40%. In addition, through a three‐dimensional excitation–emission matrix fluorescence analysis, it was possible to elucidate the degradation of C 6 H 6 O and some possible polycyclic aromatic hydrocarbons present in the effluent. The results suggested that 65%–90% of the hydrocarbons and C 6 H 6 O present in the effluent were degraded with the SnO 2 –RuO 2 –IrO 2 |Ti anode applying 25 mA cm −2 within the first 30 min of electrolysis, reaching almost 99% degradation at 90 min. The EO process using SnO 2 –RuO 2 –IrO 2 |Ti can be an alternative for tertiary treatment of oil refinery wastewater for degradation and mineralization of the remaining organic matter of secondary effluents (biological processes) via active chlorine species.