β-FeOOH的无模板水热合成及其光催化降解偶氮染料甲基橙的研究

Study of template-free hydrothermal synthesis of β-FeOOH and its catalytic degradation for azo dye methyl orange

以尿素为均相沉淀剂,无模板水热合成了纳米棒状的β-FeOOH。采用X射线衍射和场致扫描电镜技术表征制备样品。在异相光芬顿反应中研究β-FeOOH降解甲基橙的效率。结果显示:50 min内甲基橙能被异相光催化过程中产生的羟基自由基降解100%;当反应液初始pH值增加到9.5,50 min内甲基橙的降解效率仅下降到93.45%,这意味着制备的β-FeOOH催化剂能很好地克服均相光芬顿反应中pH值范围狭窄的缺点。β-FeOOH催化剂的装载量和H2O2浓度同样对甲基橙降解效率有重要影响。β-FeOOH催化剂多次重复使用后仍然具有保持较高催化活性的能力。

The nanorod-shaped akaganeite was prepared by the template-free hydrothermal method with urea as the homogeneous pre- cipitant. X-ray diffraction and field-emission scanning electron microscope were used to identify the resulting products. The degradation efficiency of methyl orange （MO） was studied using the prepared akaganeite materials during photo-Fenton-like reaction. MO degradation efficiency of 100% was achieved by hydroxyl radicals that were generated in the heterogeneous catalysis process at pH 4.5 and within 50 min. The photodegradation efficiencies only slightly decreased to 93.45% within 50 min when the initial pH of reaction solution was increased to 9.5, which indicated that the prepared β-FeOOH catalyst could well overcome the drawback of a narrow pH range of homogeneous Fenton reaction. β-FeOOH catalysts loading and H2O2 concentration also produced the important effects on the degradation efficiency of MO. The prepared β-FeOOH showed good ability of relatively high catalytic activity for reuse trials.