纳米α-Fe_2O_3/H_2O_2异相Fenton催化降解酸性橙7

Degradation of Acid Orange 7 in Nano-α-Fe_2O_3/H_2O_2Heterogeneous Fenton Reaction System

以水热法制备纳米α-Fe_2O_3,并应用于异相Fenton体系中催化降解酸性橙7。用扫描电子显微镜(SEM)、X射线衍射仪(XRD)表征样品的结构;在异相Fenton催化体系中,通过优化初始p H、初始底物浓度、双氧水添加量、α-Fe_2O_3添加量、温度,探究合适的催化降解条件,通过多次循环催化对催化剂稳定性进行研究,并通过催化过程中产生的自由基,分析其催化机理。结果表明,α-Fe_2O_3为长约70 nm,宽约20 nm的均匀单一纳米棒。在异相Fenton催化体系中,最佳催化条件为初始p H=3.0,初始底物质量浓度200 mg/L,反应温度为30℃,双氧水的添加量为w(H_2O_2)=1.5%,催化剂α-Fe_2O_3添加量为500 mg/L,在反应120 min时脱色率为98.74%,COD去除率为73%;稳定性良好,铁离子溶出量低于0.8 mg/L,循环实验5次脱色率始终在90%以上;此外,对自由基的研究表明,·OH在本体系降解过程中占主要作用。

Nano-α-Fe_2O_3 was synthesized by a facile hydrothermal method and further utilized as a heterogeneous Fenton catalyst for the degradation of acid orange 7. The structure of α-Fe_2O_3 was characterized by scanning electron microscopy（ SEM） and X-ray diffraction（ XRD）. And the effect of various operating conditions was studied,namely initial p H,substrate concentration,hydrogen peroxide dosage,catalyst dosage,and reaction temperature. In addition,the stability of nano-α-Fe_2O_3 was investigated and the catalytic mechanism was also analyzed according to the generated free radicals. The results showed that α-Fe_2O_3 exhibited a rod-like morphology with a width of 20 nm and a length of 70 nm. The optimized conditions were 3. 0 of initial p H,200 mg / L of substrate mass concentration,30 ℃of reaction temperature,1. 5% of hydrogen peroxide mass concentration,500 mg / L of catalyst dosage.Under the above conditions,the degradation rate and COD removal rate of acid orange 7 were up to98. 74% and 73%,respectively,after 120 min. The α-Fe_2O_3 exhibited an excellent stability. The concentration of the dissolved iron ions was lower than 0. 8 mg / L and the degradation rate of acid orange 7 was over 90% after five successive reaction. The mechanism research showed that ·OH plays a critical role in this system.