FeII/FeIII internal cycle in CoFeIIFeIII-LDHs for enhanced electro-Fenton degradation of N,N-dimethylacetamide

Heterogeneous Fe-based electro-Fenton process has gained extensive attention for the refractory pollutants control. Nevertheless, insufficient Fe II /Fe II I cycle is still the key limitation to enhance the Fenton reaction. Herein, a strategy on the efficient Fe II /Fe III internal cycle using CoFe II Fe III -layered double hydroxides (CoFe II Fe III -LDHs) has been proposed, in which Fe species are atomically-distributed facilitating the interfacial charge-transfer and redox response. In the degradation of N,N-dimethylacetamide (DMAC), a typical organic pollutant in wastewater derived from pharmaceutical production, acrylic fibers, electronic chemicals, and fine chemical industries, the critical factors influencing degradation of DMAC were examined in detail. The degradation efficiency and the catalyst stability were investigated. CoFe II Fe III -LDHs achieved a DMAC removal of 100% within 75 min with an apparent rate constant of 0.0594·min −1 and a TOC removal of 70% after 4 h under the condition of DMAC concentration (50 mg·L −1 ), pH value (pH = 4), current density (40 mA·cm −2 ), O 2 flow rate (40 mL·min −1 ), and catalyst dosage (1.6 g·L −1 ), and the DMAC removal remained >93% after five cycles, which were both considerably superior to that only containing Fe II or Fe III . Moreover, the main free radicals and degradation pathways were elucidated according to radical capture experiments and mass spectrometry. The strategy was well tolerated in treating various organic pollutants.