Perfluorinated organic compounds (PFC) are an important group of pollutants, which are difficult to be degraded in conventional water treatment. Even hydroxyl radical based processes are not capable to degrade these compounds. Sulfate radicals can oxidize a group of PFCA, i.e., perfluorinated carboxylic (PFCAs) acids. However, information in literature on kinetics and reaction mechanism is largely based on model simulations which are prone to errors. The present study provides mechanistic insights based on product formation, material balances, competition kinetics experiments and quantum chemical calculations. Furthermore, energy requirements for sulfate radical based degradation of PFCA is evaluated in the present study. PFCAs can be partly mineralized in chain reactions initiated by SO₄^●─. The perfluorinated acetic acid, propionic acid, and butanoic acid are completely degraded in a primary reaction with sulfate radicals. In case of PFCA with chain length of > 4 carbons low yields of PFCA products were observed. Regarding reaction kinetics sulfate radicals react very slow with PFCAs (≈ 10⁴ M^-1 s^-1). Thus, the energy demand required for generation of SO₄^●─ by photolysis of S₂O₈^2─ (UV/S₂O₈^2-) is very high. A 90 % degradation of a PFCA by UV/S₂O₈^2- was estimated to be 55 kWh m^-3 in pure water.

中文翻译：

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硫酸根自由基降解全氟化合物的新机理和经济考虑

全氟有机化合物（PFC）是重要的污染物，在常规水处理中很难降解。甚至基于羟基自由基的方法也不能降解这些化合物。硫酸根可氧化一组PFCA，即全氟羧酸（PFCA）酸。但是，有关动力学和反应机理的文献资料主要基于容易出错的模型模拟。本研究提供了基于产品形成，材料平衡，竞争动力学实验和量子化学计算的力学见解。此外，在本研究中评估了基于硫酸根的PFCA降解所需的能量。PFCA可以在SO ₄引发的链反应中部分矿化^●。全氟乙酸，丙酸和丁酸在与硫酸根的初级反应中被完全降解。在PFCA的链长大于4个碳的情况下，观察到PFCA产物的低收率。关于反应动力学，硫酸根与PFCA的反应非常慢（≈10 ⁴ M ^-1 s ^-1）。因此，需要用于产生的SO能量需求₄ ^●─由S的光解₂ ö ₈ ^2─（UV / S ₂ ö ₈ ^2-）是非常高的。UV / S ₂ O ₈ ^2-对PFCA的90％降解估计为55 kWh m ^-3 在纯净水中。