Defect electrons accelerate iron cycle of novel Fe-based Fenton: Long-term effective quinoline degradation

Abstract

Heterogeneous Fenton has been widely used in the disposal of organic pollutants, however, slow regeneration of Fe(II) remains limitation for its practical application of long-term treatment. Herein, we come up with a novel Fe-based heterogeneous Fenton catalyst named as FeSxOy-X (X is the ratio of ethylene glycol to N,N-dimethylformamide). With the help of the abundant defect electrons in Sulfur vacancies, Fe(II) regeneration on the surface of FeSxOy-1:1 was accelerated, resulting in a stable proportion of Fe(II) on the surface, which maintained continuously stable generation of hydroxyl radical (•OH) and singlet oxygen (1O2). Thus, without any organic reagents or cocatalysts, FeSxOy-1:1 based Fenton system achieved effective long-term degradation of 560 mg/L quinoline within only 7 days, which was evidently better than reported FeS and SV-FeS2 (SV: Sulfur vacancy). The system had excellent adaptability to water quality and the COD removal rate of biochemical wastewater was as high as 79.8%.