Boron carbide boosted Fenton-like oxidation: A novel Fe(III)/Fe(II) circulation

Abstract

The sluggish kinetics of Fe(Ⅱ) recovery in Fenton/Fenton-like reactions significantly limits the oxidation efficiency. In this study, we for the first time use boron carbide (BC) as a green and stable promotor to enhance the reaction of Fe(Ⅲ)/H2O2 for degradation of diverse organic pollutants. Electron paramagnetic resonance analysis and chemical quenching/capturing experiments demonstrate that hydroxyl radicals (•OH) are the primary reactive species in the BC/Fe(Ⅲ)/H2O2 system. In situ electrochemical analysis indicates that BC remarkably boosts the Fe(Ⅲ)/Fe(Ⅱ) redox cycles, where the adsorbed Fe(Ⅲ) cations were transformed to more active Fe(Ⅲ) species with a higher oxidative potential to react with H2O2 to produce Fe(Ⅱ). Thus, the recovery of Fe(Ⅱ) from Fe(Ⅲ) is facilitated over BC surface, which enhances •OH generation via Fenton reactions. Moreover, BC exhibits outstanding reusability and stability in successive cycles and avoids the secondary pollution caused by conventional organic and metalliferous promotors. Therefore, metal-free BC boosting Fe(Ⅲ)/H2O2 oxidation of organics provides a green and advanced strategy for water decontamination.

Keywords

• Boron carbide
• Fenton-like reaction
• Hydroxyl radical
• Metal-free catalysis
• Sulfamethoxazole