Efficacious Reduction of Ferric Ions by Molybdenum Carbide in the Peroxydisulfate Fenton-Like Reaction for Dexamethasone Degradation
Yao Xiang, Deling Yuan, Eryu Zhu, Tongtong Zhao, Tifeng Jiao, Qingrui Zhang, Shoufeng Tang
Abstract
The tardy Fe 2+ regeneration and the limited pH range confine the practical application of Fe-based homogenous Fenton-like reaction performance. To surmount the abovementioned obstacles, we applied molybdenum carbide (β-Mo 2 C) as the cocatalyst to boost Fe 3+ reduction in the activation of peroxydisulfate (PDS) for the efficient degradation of dexamethasone (DXM). The proposed Fe 3+ /PDS/β-Mo 2 C can remove more than 90% DXM in the wide pH range (3.4 to 9.4). Electron spin resonance analysis and probe and quenching tests comprehensively demonstrated that a series of reactive species ( • OH, SO 4 •–, O 2 •–, 1 O 2, and Fe(IV)) were formed during the synergistic process, and SO 4 •– was the leading role. The circulation of Fe 3+ /Fe 2+ was driven by the exposed sites of Mo 2+ /Mo 4+ on the β-Mo 2 C, which further promoted the PDS activation. The reaction mechanism was clarified by various characterizations and density functional theory calculation, which indicated that the adsorption between Fe 3+ and β-Mo 2 C could form Mo–Fe bonds and lengthen Fe–O and then improve the electron transport from β-Mo 2 C to Fe 3+ and boost Fe 3+ reduction. The reactivity and stability of β-Mo 2 C was higher than those of popular Mo-based materials. This work represents an attempt and possibility for Mo-based inorganic cocatalysis of advanced oxidation processes.