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Humic acid coated Fe₃O₄ magnetic nanoparticles as highly efficient Fenton-like catalyst for complete mineralization of sulfathiazole

Niu, Hongyun, Zhang, Di, Zhang, Shengxiao, Zhang, Xiaole, Meng, Zhaofu, Cai, Yaqi
Journal of hazardous materials 2011 v.190 no.1-3 pp. 559-565
aqueous solutions, carbon, carbon dioxide, catalysts, electron transfer, humic acids, hydrogen peroxide, iron, iron oxides, mineralization, nanoparticles, nitrogen, sulfathiazole
Humic acid coated Fe₃O₄ magnetic nanoparticles (Fe₃O₄/HA) were prepared for the removal of sulfathiazole from aqueous media. Fe₃O₄/HA exhibited high activity to produce hydroxyl (OH) radicals through catalytic decomposition of H₂O₂. The degradation of sulfathiazole was strongly temperature-dependent and favored in acidic solution. The catalytic rate was increased with Fe₃O₄/HA dosage and H₂O₂ concentration. When 3gL⁻¹ of Fe₃O₄/HA and 0.39M of H₂O₂ were introduced to the aqueous solution, most sulfathiazole was degraded within 1h, and >90% of total organic carbon (TOC) were removed in the reaction period (6h). The major final products were identified as environmentally friendly ions or inorganic molecules (SO₄ ²⁻, CO₂, and N₂). The corresponding degradation rate (k) of sulfathiazole and TOC was 0.034 and 0.0048min⁻¹, respectively. However, when 3gL⁻¹ of bare Fe₃O₄ were used as catalyst, only 54% of TOC was eliminated, and SO₄ ²⁻ was not detected within 6h. The corresponding degradation rate for sulfathiazole and TOC was 0.01 and 0.0016min⁻¹, respectively. The high catalytic ability of Fe₃O₄/HA may be caused by the electron transfer among the complexed Fe(II)-HA or Fe(III)-HA, leading to rapid regeneration of Fe(II) species and production of OH radicals.