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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (04): 345-350. 上一篇    下一篇

研究论文

无机阴离子、异丙醇及TiO2对Fe3＋诱导全氟辛酸光化学降解影响的研究

王媛，张彭义*   

  1. (清华大学环境科学与工程系 环境模拟与污染控制国家重点联合实验室 北京 100084)
  • 投稿日期:2009-08-10 修回日期:2009-09-25 发布日期:2010-02-28
  • 通讯作者: 张彭义 E-mail:zpy@tsinghua.edu.cn
  • 基金资助:

    国家自然科学基金（20577026）

Effects of Inorganic Anion, Isopropanol and TiO2 on Photochemical Degradation of Perfluorooctanoic Acid (PFOA) Mediated by Ferric Ion Wang Yuan Zhang Pengyi

,Peng-Yi Zhang   

  1. (State Key Joint Laboratory of Environmental Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China)
  • Received:2009-08-10 Revised:2009-09-25 Published:2010-02-28
  • Contact: Peng-Yi Zhang E-mail:zpy@tsinghua.edu.cn

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254 nm紫外光辐照下, 溶解性Fe3＋的存在有效促进了全氟辛酸(PFOA)的光化学降解. Fe3＋浓度为30 μmol•L－1时, Fe2(SO4)3, FeCl3和Fe(NO3)3三种溶解性铁盐对PFOA的降解和脱氟没有显著的差别. 过量的与Fe3＋具有较强的形成配合物的能力, 由软件Visual MINTEQ 2.52计算得出, Fe3＋与过量的形成Fe(SO4)＋和Fe(SO4)两种形态的配合物, 其分配比的总和占16.32%, 从而减少了PFOA与铁离子形成配合物的机会, 进而抑制了其有效的光化学降解; 过量的Cl－与Fe3＋形成一配位的FeCl2＋, 其生成量仅占所有铁物种形态总和的0.12%, 对PFOA的降解没有明显的影响, 理论计算与实验结果相一致. 羟基自由基捕获剂-异丙醇的加入未抑制PFOA的降解, 二氧化钛的存在亦未促进其降解, 进一步表明Fe3＋诱导PFOA的光化学降解不是羟基自由基直接作用的结果.

关键词: 光化学降解, 全氟辛酸, 铁离子, 无机阴离子, 羟基自由基

Photochemical degradation of PFOA was greatly accelerated by soluble Fe3＋under irradiation of 254 nm UV light. When the concentration of Fe3＋ was kept at 30 μmol•L－1, Fe2(SO4)3, FeCl3 and Fe (NO3)3 had no obvious difference in accelerating the degradation and defluorination of PFOA. Sulphate ion () exhibits stronger potential than chloride (Cl－) to coordinate with Fe3＋. According to the calculation results with Visual MINTEQ 2.52, when excessive was added ([]total/[Fe3＋]total＝50∶1, pH＝3.69), about 16.32% of total ferric ion existed in the form of Fe(SO4)＋and Fe(SO4), which reduced the probability of Fe3＋ coordination with PFOA and correspondingly inhibited the photochemical degradation of PFOA. While only 0.12% of total Fe3＋ complexed with Cl－ when excessive Cl－ was added, which had little impact on the degradation of PFOA. Theoretical calculations were consistent with the experimental results. The addition of hydroxyl radical scavenger (isopropanol) did not substantially decrease the degradation of PFOA and the presence of TiO2 did not increase the degradation of PFOA, which further indicated that the photochemical degradation of PFOA induced by Fe3＋ did not abide by oxidation mechanism of hydroxyl radical.

Key words: photochemical degradation, perfluorooctanoic acid, ferric ion, inorganic anion, hydroxyl radical