Performance and mechanism of selective degradation of phenolic pollutants by peroxydisulfate activated over oxygen doped graphic carbon nitride nanosheets
Oxygen doped graphic carbon nitride(O-CN)nanosheets was prepared via thermal exfoliation by using tannic acid as the oxygen source,aiming to tuning the surface electronic structures of carbon nitride and enhancing its performance toward the activation of peroxydisulfate(PDS)and degradation of phenolic pollutants.The variation of the electronic structure of O-CN nanosheets induced by oxygen doping was investigated.The performance and mechanism of PDS activation and phenolic pollutants degradation over O-CN was studied systematically.The results showed that oxygen doping mainly occurred on nitrogen positions,leading to redistribution of surface electrons and formation of unpaired electrons,which greatly enhanced the activation of PDS and degradation of phenolic pollutants.Under neutral conditions and the mole ratio of 1:10 for phenolic pollutants to PDS,phenolic pollutants(such as bis-phenol A,phenol and acetaminophen)could be completely removed by O-CN(0.1 g·L-1)within 60 min.The degradation of phenolic pollutants was mainly depended on electron transfer regime according to the electron paramagnetic resonance tests(EPR),chemical quenching experiments,in situ Raman analysis and electrochemical measurements.The nonradical oxidation pathway led to good anti-interference capability to complex surroundings like inorganic ions.The O-CN nanosheets showed a good stability and can be used to construct catalytic membrane for degrading phenolic pollutants continuously.Complete removal of bis-phenol A with a high mineralization efficiency(60％)occurred during 10 h of operation.
advanced oxidation processgraphitic carbon nitrideoxygen dopingphenolic pollutantselectron transfer
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