Perfluorooctanoic acid (PFOA) is widespread in the environment, which causes serious health and safety concerns. A mechanistic study on reductive defluorination of PFOA by titanium (III) citrate in the presence of catalysts was conducted. Vitamin B₁₂ was used to catalyze reduction reactions by shuttling electrons from a reducing agent (electron donor) to PFOA to produce a Co-carbon bond intermediates. In the presence of copper nanoparticles, a precursor complex, B₁₂-C₇F₁₄COOH, adsorbed on the metal surface, followed by a hydrogenolytic reaction to form less-fluorinated products. The synergistic effect between vitamin B₁₂ and copper nanoparticles enhances the reductive activities by electron-transfer reactions and hydrogenolysis. The efficient reduction of PFOA to less-noxious compounds was demonstrated with a copper dose of 2 g L⁻¹, titanium(III) citrate (45 mM), and vitamin B₁₂ (0.2 mM) with an initial pH of 9.0 and 70 °C. In this anoxic aqueous solution, the biomimetic reductive system effectively removed 65% of PFOA. The mass balance on fluoride matched the observed degradation of PFOA, while no short-chain intermediates were detected.

中文翻译：

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维生素B ₁₂和铜纳米粒子对柠檬酸钛（III）的全氟辛酸还原脱氟

全氟辛酸（PFOA）在环境中广泛存在，这引起了严重的健康和安全隐患。在催化剂存在下，进行了柠檬酸钛（III）对PFOA的还原脱氟的机理研究。维生素B ₁₂用于通过将电子从还原剂（电子供体）传递到PFOA来催化还原反应，从而生成Co-碳键中间体。在铜纳米颗粒的存在下，前体络合物B ₁₂ -C ₇ F ₁₄ COOH吸附在金属表面，然后进行氢解反应以形成较少的氟化产物。维生素B ₁₂之间的协同作用铜纳米颗粒通过电子转移反应和氢解作用增强了还原活性。在初始pH值为9.0和70°C的情况下，铜剂量为2 g L ^-1，柠檬酸钛（III）（45 mM）和维生素B ₁₂（0.2 mM）时，证明了PFOA可以有效地还原为低毒化合物。C。在这种缺氧水溶液中，仿生还原系统有效去除了65％的PFOA。氟化物上的质量平衡与观察到的PFOA降解相匹配，而未检测到短链中间体。