(catalytic) Ozonatiom Of Nitrogen-containing Heterocyclic Organic Compounds:Degradation Reaction And Mechanism

Nitrogenous heterocyclic compounds?NHCs?are widely used in industry and daily life,which entered the water caused extremely damage.In this paper,Ozonation was used to degrade NHCs,studied the reaction rate constants of NHCs with O₃,then based on the structural characteristics of different nitrogen atoms in NHCs,the distribution of electron density in frontier orbits in the framework of density functional theory?DFT?,and the softness of NHCs was calculated and the reaction activity of NHCs was predicted.The softness of NHCs was positively correlated with the reaction rate constant.The potential active sites of ozone direct oxidation and free radical attack were detected by mass spectrometry?MS?analysis combined with Fukui function,and the degradation pathway of NHCs was further established.At the same time,produced active oxygen was analyzed by electron paramagnetic resonance?EPR?and quenching test.Hydroxyl radical?·OH?was still the main product of ozone self-decomposition,and the contribution of singlet oxygen?¹O₂?to ozone oxidation degradation could be neglected.Three kinds of N,S co-doped hollow carbon spheres?C-800,C-900,C-1000?were prepared to improve the efficiency of ozone degradation of target pollutants.N,S co-doped hollow carbon sphere catalysts are hollow carbon spheres with microporous structure,which were provided with specific surface of C-800:655.35 m2/g;C-900:664.11 m2/g;C-1000:708.15 m2/g,respectively.The results of catalytic ozonation degradation experiment showed that C-1000 took on the best catalytic activity.The degradation efficiency of C-1000 was 29.4%higher than ozonation alone at 45 min.BAT results found that C-1000 had larger specific surface area and better adsorption effect.XPS and FTIR results showed that C-1000 possessed more oxygen functional groups on the surface than the other two catalysts,and for doped nitrogen and sulfogen atoms.It was found that the increase of graphite nitrogen and oxygen-containing sulfur content would enhance the catalytic activity of the catalyst.In order to explore the catalytic degradation effect of different catalysts,three perovskite catalysts?LaMnO₃,Co₂MnO₄,BaMnO₃?were prepared to catalyze ozonation degradation of benzimidazole?BMZ?.The results showed that the degradation efficiency of catalytic ozonation from low to high was LaMnO₃<Co₂MnO₄<BaMnO₃.The results showed that the average oxidation state?AOS?was mixed valent metal oxygen.The real valence index,lower AOS of manganese is beneficial to the catalytic activity.The average oxidation state of BaMnO3 perovskite verifies the best catalytic activity of BaMnO₃ perovskite.