Practical considerations for the electrochemical denitrification of real wastewater. Issue 1 (25th November 2022)

• Record Type: Journal Article
• Authors: Li, Dehui; Fu, Cheng; Wang, Chan; Song, Qijun
• Is Part Of: Environmental science. Volume 9:Issue 1(2023)
• Page Start: 211
• Page End: 220
• Publication Date: 2022-11-25
• Subjects: Water-supply -- Periodicals; Water security -- Periodicals; Water resources development -- Periodicals; Water chemistry -- Periodicals; 553.705
• DOI: 10.1039/d2ew00346e
• Languages: English
• ISSNs: 2053-1400

Abstract

Abstract : The factors that influence the practical application of the electroreduction of NO3 − are systematically elaborated. Abstract : High concentrations of nitrate (NO3 − ) in water is a serious threat to the environment and human health. Therefore, there is an urgent to explore and develop real wastewater treatment methods. In this study, the electrochemical reduction of NO3 − using brass as the cathode and IrO2 –RuO2 /Ti as the anode was studied, and the influence of various conditions, including the current density, conductivity, initial pH, Cl − concentration and, coexisting matter (PO4 3−, CO3 2−, Ca 2+, and organics), were systematically investigated. The optimized method was verified for the reduction of NO3 − in simulated wastewater and real wastewater. It was found that in the presence of 500 mg L −1 Cl −, a reduction rate above 80% could be readily achievable for 50 mg L −1 NO3 − –N in 100 min electrolytic treatment at a current density of 10 mA cm −2 . The presence of CO3 2− and Ca 2+ had no significant effect on NO3 − reduction, but the presence of PO4 3− could substantially decrease the reduction rate of NO3 − –N due to the competitive adsorption of HPO4 2− and H2 PO4 − on the brass electrode. The interference from PO4 3− could be largely alleviated by the addition of Ca 2+ to the sample solution. The presence of organic matters also adversely influenced the reduction rate of NO3 − –N, whereby the reduction rate of NO3 − –N decreased to 71.1% in a solution with 200 mg L −1 COD. As the organic matter could be degraded in prolonged electrolytic treatment, our method showed good adaptability for real water treatment. The results obtained in the present study demonstrated that the electrolytic method with brass as the cathode and IrO2 –RuO2 /Ti as the anode not only had a satisfactory efficiency for NO3 − –N removal but also exhibited good durability in real water treatment.