Role of weak magnetic field for enhanced oxidation of orange G by magnetic Fenton

Shi, Zhenyu; Zhang, Ruijia; Zhang, Jing

Role of weak magnetic field for enhanced oxidation of orange G by magnetic Fenton

2021

Shi, Zhenyu | Zhang, Ruijia | Zhang, Jing

The role of weak magnetic field (WMF) on the degradation of a common textile azo-dye, orange G (OG), by magnetic Fenton system was investigated in detail. The results showed that the presence of WMF can provide better performance of the Fe₃O₄/H₂O₂ system for OG degradation. The optimized reaction conditions were contained at 1 mM Fe₃O₄ as Fe, 20 mT of magnetic field intensity, 20 mM H₂O₂, and initial pH of 3.0. The removal efficiency of OG by Fe₃O₄/H₂O₂ coupling with WMF increased largely from 56.3 to 82.3% compared with Fe₃O₄/H₂O₂ process. Both the electron paramagnetic resonance (EPR) analysis and the quenching effect of tert-butyl alcohol (TBA) confirmed that hydroxyl radical (•OH) was the primary reactive oxygen species in WMF-Fe₃O₄/H₂O₂ system. The improving effect of WMF was explained by the magnetoconvection theory. The presence of WMF could accelerate the corrosion rate of Fe₃O₄ and thus promoted the release of Fe(II), which led to the increased production of •OH and enhanced the degradation of OG. Moreover, it was surprising to observe that the WMF induced improvement in OG degradation by heterogeneous Fenton involving the iron sludge, namely FeOOH and Fe₂O₃, as catalysts. These results indicated that WMF could be utilized as an efficient and cost-effective strategy to improve the removal of organic pollutants by iron oxide–based Fenton process.

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