Iron oxide (FeOOH or Fe2O3) nanorods loaded on carbon nanofiber (CNF) sheets were found to be active in degrading aromatic pollutants spontaneously under dark ambient condition without using any chemical reagents or external energy to assist the degradation reaction. The removal of aromatic pollutants was caused not by adsorption but by oxidative degradation since the production of degradation intermediates and CO2 was observed. The iron oxide/CNF composites exhibited selective degradation activities for aromatic compounds, whereas the oxidation of dichloroacetic acid (DCA), ethylenediaminetetraacetic acid (EDTA), and As(III) was negligible. Degradation was observed only on iron oxide loaded on CNFs, whereas neither iron oxide nor CNF alone showed any degradation activity. The oxidative degradation on the iron oxide/CNF was enabled only in the presence of dissolved O2 of which reduction led to spontaneous generation of reactive oxygen species (ROS) such as superoxide radical and hydroxyl radical. The production of ROS under dark ambient condition was confirmed by various tests using ROS probe reagents and spin-trap electron paramagnetic resonance experiment. It is proposed that electrons transfer spontaneously from aromatic compound to O2 via the iron oxide/CNF support with initiating the oxidative degradation and the concurrent ROS generation. The oxidative degradation could be also initiated by the direct electron transfer from an organic compound to the iron oxide/CNF electrode, which was successfully demonstrated by measuring the spontaneous current generation upon spiking the organic probe compound into the electrolyte solution.

Spontaneous oxidative degradation of aromatic compounds on iron oxide nanorods/CNF sheet in dark condition

2019 Fall National Meeting

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