化学学报 ›› 2017, Vol. 75 ›› Issue (9): 866-872.DOI: 10.6023/A17020060 上一篇    下一篇

研究论文

球磨微米硫化零价铁活化双氧水降解有机污染物的研究

黄丹维, 何佳, 谷亚威, 何锋   

  1. 浙江工业大学环境学院 杭州 310014
  • 收稿日期:2017-05-01 出版日期:2017-09-15 发布日期:2017-09-21
  • 通讯作者: 何锋 E-mail:fenghe@zjut.edu.cn
  • 基金资助:

    浙江省自然科学基金杰出青年基金项目资助(No.LR16E08003).

Mechanochemically Sulfidated Zero Valent Iron as an Efficient Fenton-like Catalyst for Degradation of Organic Contaminants

Huang Danwei, He Jia, Gu Yawei, He Feng   

  1. College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
  • Received:2017-05-01 Online:2017-09-15 Published:2017-09-21
  • Contact: 10.6023/A17020060 E-mail:fenghe@zjut.edu.cn
  • Supported by:

    Project supported by the Natural Science Foundation of Zhejiang Province (No. LR16E08003).

报道了机械球磨方法制备的微米硫化零价铁(S-ZVI)可以快速活化H2O2降解各类有机污染物.S-ZVI/H2O2降解苯酚的单位比表面积反应速率常数是ZVI/H2O2的5倍以上,且苯酚的降解不存在初始抑制阶段.探针化合物乙醇的淬灭反应结合电子顺磁共振(EPR)实验证明S-ZVI/H2O2体系产生的氧化活性物质为·OH.反应前后S-ZVI颗粒的扫描电子显微镜(SEM)和X射线衍射(XRD)表征结合电化学测试和苯酚降解结果表明S-ZVI中FeS取代ZVI表面的钝化膜(铁氧化物),加速了电子从Fe0传递到H2O2,更快地释放Fe2+,引发Fenton反应.在这过程中FeS主要作为电子的导体而非Fe2+的释放源.

关键词: 机械球磨, 硫化零价铁, 硫化亚铁, 非均相Fenton反应, 羟基自由基

Mechanochemically sulfidated zero valent iron (S-ZVI), prepared from ball milling of ZVI and sulfur powder, was used as a catalyst for heterogeneous Fenton oxidation of a variety of persistent organic compounds including phenol, chlorophenols, nitrobenzene, bisphenol A and tetracycline. The 100% removal of phenol was achieved within 1 min in S-ZVI/H2O2 system while it took 10 min in ZVI/H2O2 system. The initial surface area normalized phenol degradation rate by S-ZVI was 5 times of that of ZVI, suggesting the much higher efficiency of S-ZVI in catalyzing the decomposition of H2O2 for oxidative degradation of organic contaminants. In addition, an initial lag period of phenol degradation in ZVI/H2O2 system was absent in S-ZVI/H2O2 system. The removal efficiency of phenol was dependent on the initial H2O2 concentration, S-ZVI dosage, initial phenol concentration, and pH. The optimum pH and H2O2 concentration was 3.0 and 2 mmol·L-1, respectively, when the initial phenol concentration was 0.2 mmol·L-1 and the S-ZVI dosage was 0.12 g·L-1. The phenol degradation was effectively scavenged by a ·OH probe compound, ethanol and the electron paramagnetic resonance (EPR) studies successfully detected DMPO (5,5-dimethyl-1-pyrroline-N-oxide)-OH signals, which collectively suggests that the reactive species responsible for contaminant degradation in S-ZVI/H2O2 system was ·OH. S-ZVI particles before and after reaction were characterized by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD). SEM-EDS results showed that the oxidation of S-ZVI by H2O2 resulted in the formation of iron hydroxide nanoparticles on the particle surface while FeS was not significantly consumed. Tafel analysis of S-ZVI and ZVI modified electrodes demonstrated that S-ZVI had a greater overall rate of electron transfer than ZVI. Therefore, FeS as a better electron conductor facilitated the electron transfer from Fe0 to H2O2 resulting in faster Fe2+ releasing and H2O2 activation, which enhanced contaminant deg-radation.

Key words: ball milling, sulfidated zero valent iron, iron sulfide, heterogeneous Fenton reaction, hydroxyl radical