维生素B12催化纳米零价铁仿生降解全氟辛磺酸

研究了维生素B₁₂（VB₁₂）催化纳米零价铁（nFe⁰）仿生还原降解工业级全氟辛磺酸（PFOS）.结果表明，VB₁₂催化nFe⁰不仅能够降解支链PFOS，而且也能够同时降解直链PFOS，这是首次报道直链PFOS的仿生还原降解.PFOS降解过程可用准一级动力学模型模拟，且升高温度有利于PFOS的还原降解去除和脱氟.超高效液相色谱-四级杆飞行时间质谱（UPLC-QTOF）定性分析表明，PFOS仿生降解产物包括4种全氟磺酸类（全氟碳链长度为C4~C7）、9种全氟羧酸类（全氟碳链长度为C2~C7、C10、C11和C13）和5种多氟代酸类（即H-全氟己酸、H-全氟庚酸、H-全氟辛酸、H₂-全氟辛酸和H-全氟辛磺酸）化合物.全氟磺酸类和全氟羧酸类化合物首次在VB₁₂仿生催化降解PFOS的产物之中检出，其中全氟十一烷酸（C10）、全氟十二烷酸（C11）和全氟十四烷酸（C13）等长链化合物第一次在降解PFOS过程中被发现.在降解样中检出的H-全氟烷烃（链长为C2~C7、C10、C11和C13）是否是PFOS的仿生降解产物，还有待进一步研究确认.

Biomimetic degradation of PFOS catalyzed by vitamin B12 using nanoscale zero-valent iron as reductants

The reductive degradation of technical perfluorooctanesulfonate (PFOS) were investigated in a biomimetic system consisting of vitamin B₁₂(VB₁₂) as catalyst and nanoscale zero-valent iron (nFe⁰) as reductants. Both branched and linear PFOS could be degraded simultaneously, and the biomimetic degradation of linear PFOS was first reported. The degradation was well described by a pseudo-first-order kinetic model, and increasing the incubation temperature was favorable for the removal of PFOS and for its defluorination. Three types of PFOS degradation products, including 4 perfluoroalkylsulfonates (perfluorocarbon chain length:C4~C7), 9perfluorocarboxylates (perfluorocarbon chain length:C2~C7, C10, C11, and C13), and 5 polyfluorinated acids (i.e. H-perfluorohexanoate, H-perfluoroheptanoate, H-perfluorooctanoate, H₂-perfluorooctanoate, and H-perfluorooctanesulfonate) have been qualitatively determined by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF). For the first time, Perfluoroalkylsulfonates and perfluorocarboxylates were detected among the biomimetic reduction products of PFOS catalyzed by VB₁₂, while some long-chain perfluorocarboxylates, including perfluoroundecanoate (C10), perfluorodocecanoate (C11) and perfluorotetradecanoate (C13), were first reported as the degradation products during decomposition of PFOS. It was unclear whether H-perfluoroalkanes (carbon chain length:C2~C7, C10, C11, and C13) were the biomimetic degradation products of PFOS, and further investigation is warranted.