Perfluorooctane sulfonate (PFOS) is an extremely persistent man-made chemical that has drawn attention because of its ubiquitous presence in the environment, resistance to degradation and toxicity to animals. The extensive usage of PFOS in industrial and daily consumer products leads to its frequent detection in various environmental matrices. The U.S. Environmental Protection Agency (EPA) has classified PFOS as an emerging contaminant. Therefore, there is an urgent need to develop a feasible treatment and remediation strategy to address PFOS contamination. This research investigated the degradation of PFOS by laccase-induced enzyme catalyzed oxidative humification reactions (ECOHRs) using 1-hydroxybenzotriazole (HBT) as a mediator. Approximately 59% PFOS was transformed in a mineral buffer over 162-day incubation with the initial PFOS concentration at 1.0 μM. The degradation followed the pseudo-first order kinetics with a reaction rate constant of 0.0043/d (r2 = 0.86) which was similar as the one measured for perfluorooctanoic acid (PFOA) degradation (0.0044/day, r2 =0.89). High resolution mass spectrometry analysis showed that ECOHRs transformed PFOS to partially fluorinated compounds. These products could be generated through the dissociation of SO3− group to produce perfluoroalkyl radicals, followed by radical rearrangement and coupling with other co-existed non-fluorinated radicals. This finding suggests that ECOHRs may have a great potential for removing PFOS from contaminated environment.

Degradation of perfluoroctane sulfonate by enzyme catalyzed oxidative humification reactions

251st National Meeting (2016)

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