Highly efficient simultaneous catalytic degradation and defluorination of perfluorooctanoic acid by the H2O2-carbon/MnO2 system generating O2[rad]- and [rad]OH synchronously

Abstract

Carbon/MnO2 composites including graphene/MnO2 and CNT/MnO2 were synthesized to treat perfluorooctanoic acid (PFOA) for the first time. Owing to the fast self-dispersion of carbon/MnO2 particles with H2O2 as the fuel, large solid surface area provided by carbon materials, and the effective simultaneous generation of OH and O2−, high PFOA degradation and defluorination efficiencies were achieved synchronously within 15 min. Interestingly, different OH scavengers showed opposite effects on PFOA degradation. The inhibition of PFOA degradation by nitrobenzene was due to the scavenging of OH resulting in the restraint of O2- generation. While the increasing PFOA degradation efficiency with the addition of high concentration of iso-propanol and tert-butyl alcohol was due to the less polarity of them than water resulting in the higher reactivity of O2−. Conclusively, the study provided a new alternative for the effective treatment of PFOA.