Vitamin B12 (CoII) initiates the reductive defluorination of branched perfluorooctane sulfonate (br-PFOS) in the presence of sulfide

Due to the extremely high stability of perfluorooctane sulfonate (PFOS), effective defluorination is difficult. Previous studies indicated that PFOS can be decomposed under catalysis vitamin B12 (VB12) with strong artificial reductants such as Ti(III)-citrate and nZn0. In this study, we explored if naturally occurring reductant like sulfide (S2−) could initiate reaction. S2−/VB12 system, branched (br-PFOS) undergo decomposition at temperature 70 °C pH greater than 12. The degradation br-PFOS fits pseudo-first-order kinetic a rate constant 0.0984 ± 0.0034 d-1 in presence 30 mM Na2S 300 μM VB12, while linear (L-PFOS) remained stable during d reaction process. UV–Vis spectral characterization indicates S2− reduces VB12(CoIII) CoII, which able reductive defluorination. Based on product analysis, HF/2F elimination followed by C–C scission dominant pathway instead stepwise H/F exchange. primary products include F− polyfluorinated sulfonates carboxylates. strongly dependent due relatively apparent activation energy 62.86 kJ/mol. Strong alkaline condition greatly enhance efficiency since reactive form. This study provides new insights into VB12-catalyzed feasible approach for future natural or engineered remediations br-PFOS.