Degradation of emerging contaminants by Co (III) ions in situ generated on anode surface in aqueous solution. (April 2019)

• Record Type: Journal Article
• Authors: Liu, Yongzhi; Si, Bin; Zhao, Chun; Jin, Fan; Zheng, Huaili; Wang, Zhaoyang
• Is Part Of: Chemosphere. Volume 221(2019)
• Page Start: 543
• Page End: 553
• Publication Date: 2019-04
• Subjects: Mediated electrochemical oxidation process -- Emerging contaminants -- Neutral pH -- Co (III) -- Co (II); Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.01.076
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Cobalt ion is an environmental contaminant in general. But interestingly, it can also be used to degrade some refractory organic contaminants in water by mediated electrochemical oxidation process (MEOP) based on Co (III). MEOP is a very promising technology, and it can recycling use the mediator ions, Co (III), to degrade refractory organic contaminants in water. However, previous studies for this technology mainly conducted in strong acidic medium, the oxidation ability of this process for emerging contaminants near neutral pH condition was still unclear. Therefore, this study evaluated the emerging contaminants removal and mineralization efficiency of the MEOP-Co (III) around neutral pH, and investigated systematically the influence of series of operating parameters, including initial Co (II) concentration, current density, initial pH, electrolyte, and anions. Results from these studies indicated that the MEOP-Co (III) had a fairly good contaminants removal and mineralization ability for sulfamethoxazole, tetracycline, carbamazepine, diclofenac, and phenol at neutral pH. Besides, no radical was detected in MEOP-Co (III), and the main oxidizing substance was Co (III) ions, which was generated on anode surface. The addition of C O 3 2 − / H C O 3 − could weaken the oxidation ability of MEOP-Co (III), while C l − and P O 4 3 − could enhance the system's oxidation ability. Moreover, a reasonable energy consumption was achieved in MEOP-Co (III), and the highest electric energy per order (EE/O) value was 2.4 kWh·m −3 in this study. Graphical abstract: Image 1 Highlights: In MEOP-Co (III), Co (III) ions could be electrogenerated on anode near neutral pH. The in situ generated Co (III) ions demonstrated a reasonable oxidation. Cobalt ions could be reused during the decomposition of contaminants. Reasonable energy consumption was achieved in MEOP-Co (III).