Electro-enhanced heterogeneous activation of peroxymonosulfate via acceleration of Fe(III)/Fe(II) redox cycle on Fe-B catalyst. (1st May 2021)

• Record Type: Journal Article
• Authors: Miao, Fei; Liu, Zehao; Kang, Xin; Cheng, Cheng; Mao, Xiaoyu; Li, Ruimeng; Lin, Heng; Zhang, Hui
• Is Part Of: Electrochimica acta. Volume 377(2021)
• Publication Date: 2021-05-01
• Subjects: Fe-supported bentonite -- Electric field -- Fe(III)/Fe(II) cycle -- Heterogeneous activation -- Peroxymonosulfate; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.138073
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Fe-B catalyst was fabricated for electro-assisted heterogeneous activation of PMS. Electric field could accelerate the Fe(III)/Fe(II) redox cycle. The direct anodic oxidation and surface-bound radicals were responsible for AO7 decay. Effects of important operational conditions on the AO7 abatement were explored. Abstract: Heterogeneous catalytic oxidation based on iron species for peroxymonosulfate (PMS) activation is considered as one of the most attractive strategies for wastewater treatment. However, the rate-limiting regeneration of Fe(II) from Fe(III) heavily hampers the efficient activation of PMS. In this study, the introduction of electric field to the Fe-supported bentonite (Fe-B) activated PMS process was proposed to enhance the Fe(III)/Fe(II) redox cycle. The Fe-B catalyst performed well in the removal of Acid Orange 7 (AO7) through the synergistic effect of electrolysis and the continuous redox cycle of Fe(III)/Fe(II) for PMS activation. The use of 0.5 g L −1 Fe-B catalyst and 10 mM PMS yielded nearly complete removal of the AO7 (50 mg L −1 ) in 60 min at 2 mA cm −2 of current density. Based on the results of electron paramagnetic resonance (EPR) spectroscopy, chemical quenching tests, X-ray photoelectron spectroscopy (XPS) analysis, and electrochemical measurements, the decolorization of AO7 was dominantly attributed to surface-bound radicals (SO4 − ads and OHads ) and also the direct electron transfer at DSA anode. Moreover, the electro/Fe-B/PMS system showed an effective pH range from 2.6 to 9.0 and the abatement of AO7 was slightly affected in the presence of natural background anions. This work provides a feasible strategy of PMS activation by cost-effective Fe-B catalyst coupling with electric field and gives an insight into the accelerated oxidation of recalcitrant pollutants. Graphical abstract: Image, graphical abstract