Abstract
The activities of heterogeneous Fenton and Photo-Fenton processes using pyrite (FeS2) prepared via a solvethermal method were evaluated by oxidation of p-nitrophenol (PNP). PNP could be completely ultrarapidly oxidized by Pyrite-Photo-Fenton (Pyrite-PF) system within 4 min, versus 10 min in Pyrite-Fenton (Pyrite-F) system. The excellent oxidation performance obtained by Pyrite-PF might be due to accelerated circulation between ferrous ions and ferric ions under visible light illumination, which improved generation of reactive oxygen species (ROS). X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) were applied to ascertain the morphology and crystal structure of fresh-pyrite as well as used-pyrite. According to these results, the synthesized pyrite particles performed eminent stability, and used-pyrite could even generated more ROS including hydroxyl radicals (OH) and superoxide radicals (O2-). EPR testing and quenching experiments also confirmed the generations of OH, O2- and holes (h+) during oxidation processes of PNP in both Pyrite-F and Pyrite-PF systems. The reaction pathway was proposed based on the detected intermediate products including 4-nitrocatechol, 4-nitropyrogallol, hydroquinone, benzoquinone, 1,2,4-trihydroxybenzene and 2,4-dinitrophenol. The mechanisms of PNP degradation in Pyrite-F and Pyrite-PF systems have also been studied by DFT calculations. Pyrite (111) should be responsible for the generations of free OH and surface OH.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.