Recycling of Fe3O4 nanomaterial from coal fly ash as catalyst to develop green and sustainable bio-electro Fenton: Characterization, optimization, and performance.

In this work, magnetite (Fe 3 O 4) nanomaterial was efficiently separated from the complex matrix of coal fly ash by a novel cyclic magnetic extraction device. Separated magnetite nanomaterial was selectively purified by a simple pretreatment method. The purified magnetite nanomaterial with particle size distribution of 40–400 nm was prepared for catalyzing mesotrione degradation in the bio-electro Fenton process. Under the optimal conditions, mesotrione was rapidly degraded at the rate of 1.6 mg/L/h for cathodic Fenton oxidation, which was 3.2 and 5.3 times higher than that of microbial electrochemical degradation in the microbial fuel cell anode (0.5 mg/L/h) and traditional microbial fermentation (0.3 mg/L/h), respectively. With the unique crystal structure, CFA-recycled magnetite nanomaterial exhibited stronger catalysis performance in mesotrione degradation than the commercial magnetite nanomaterial. Meanwhile, the loss rate of CFA-recycled magnetite nanomaterial was only 2.1 ± 0.4% compared with that of 20.8 ± 1.4% for commercial magnetite nanomaterial after three cycles, indicating CFA-recycled magnetite nanomaterial shows significant chemical stability and reusability. This work demonstrated the feasibility of CFA-recycled magnetite nanomaterial as an efficient, low-cost, and environmentally friendly catalyst for develop green and sustainable bio-electro Fenton process. [Display omitted] • Recycled Fe 3 O 4 nanomaterial enhanced bio-electro Fenton in MES degradation. • Recycled Fe 3 O 4 nanomaterial exhibited chemical stability and reusability. • CFA-recycled Fe 3 O 4 nanomaterial is a promising catalyst to develop sustainable Fenton. [ABSTRACT FROM AUTHOR]