Heterogeneous Fenton-Like Catalytic Degradation of 2,4-Dichlorophenoxyacetic Acid by Nano-Scale Zero-Valent Iron Assembled on Magnetite Nanoparticles

• Main Authors: Xiaofan Lv, Yiyang Ma, Yangyang Li, Qi Yang
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Water
• Subjects: 2,4-dichlorophenoxyacetic acid; nano-scale zero-valent iron; magnetite; heterogeneous Fenton-like system; hydroxyl radicals
• Online Access: https://www.mdpi.com/2073-4441/12/10/2909
• ISSN: 2073-4441

Fe⁰@Fe₃O₄ nanoparticles with dispersibility and stability better than single nano zero-valent iron (nZVI) were synthesized and combined with hydrogen peroxide to constitute a heterogeneous Fenton-like system, which was creatively applied in the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). The effects of different reaction conditions like pH, hydrogen peroxide concentration, temperature, and catalyst dosage on the removal of 2,4-D were evaluated. The target pollutant was completely removed in 90min; nearly 66% of them could be mineralized, and the main intermediate product was 2,4-dichlorophenol. Synergistic effects between nZVI and Fe₃O₄ made the 2,4-D degradation efficiency in the Fe⁰@Fe₃O₄/H₂O₂ system greater than in either of them alone. More than a supporter, Fe₃O₄ could facilitate the degradation process by releasing ferrous and ferric ions from the inner structure. The reduction of 2,4-D was mainly attributed to hydroxyl radicals including surface-bound <b>∙</b>OH and free <b>∙</b>OH in solution and was dominated by the former. The possible mechanism of this Fe⁰@Fe₃O₄ activated Fenton-like system was proposed.