Human activity and industrial production have led to phenol becoming a significant risk factor. The proper treatment of phenol in wastewater is essential. In this study, the utilization of weak magnetic field (WMF) and zero-valent iron (ZVI) was proposed to activate H2O2 to degrade phenol contaminant. The results show that the weak magnetic field has greatly enhanced the reaction rate of ZVI/H2O2 removal of phenol. The removal rates of phenol by ZVI/H2O2/WMF generally decreased with increasing initial pH and phenol concentrations, and firstly increase and then decrease with increasing Fe0 or H2O2 dosage. When the initial pH is 5.0, ZVI concentration of 0.2 g L−1, H2O2 concentration of 6 mM, and phenol concentration of 100 mg L−1 were used, complete removal of phenol can be achieved within 180 min at 25 °C. The degradation process was consistent with the pseudo-first-order kinetic model when the experimental data was fitted. The ZVI/H2O2/WMF process exhibited a 1.05–2.66-fold enhancement in the removal rate of phenol under various conditions, surpassing its counterpart lacking WMF. It was noticed that the presence of 1–5 mM of Ca2+, Mg2+, Cl−, SO42− ions can significantly enhance the kinetics of phenol removal by ZVI/H2O2 system with or without WMF to 2.22–10.40-fold, but NO3−, CO32−, PO43− inhibited the reaction significantly in the following order: PO43− > CO32− > NO3−. Moreover, pre-magnetization for 3 min could enhance the ZVI/H2O2 process which was valuable in treatment of real wastewater. The hydroxyl radical has been identified as the primary radical species responsible for phenol degradation. The presence of WMF accelerates the corrosion rate of ZVI, thereby promoting the release of Fe2+ ions, which in turn induces an increased production of hydroxyl radicals and facilitates phenol degradation. The compounds hydroquinone, benzoquinone, catechol, maleic acid, and CO2 were identified using GC-MS, and degradation pathways were proposed. Employing WMF in combination with various ions like Ca2+, Mg2+, Cl−, SO42− is a novel method, which can enhance oxidation capacity of ZVI/H2O2 and may lead to economic benefit.
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