Study On Preparation And Catalytic Ozonation Performance Of Graphene-based Materials

Ozonation process has been widely applied in water and wastewater treatment,such as for disinfection,for degradation of toxic organic pollutants.However,the utilization efficiency of ozone（O₃）is low and the incomplete degradation of organic pollutants in water mineralization of organic pollutants by ozone oxidation is ineffective.Catalytic ozonation process can overcome these problems to some extent,which has received increasing attention in recent years.In this study,graphene oxide（GO）,reduced graphene oxide（rGO）and rGO@ZnO composite were synthesized using graphite powder as the basic material to investigate its catalytic activity,stability and possibility in the catalytic ozonation system.The main contents and results of this paper are as follows:（1）GO was prepared by modified Hummers method using graphite powder as matrix material,and then rGO was prepared by redox method using GO as precursor.A series of characterization（SEM,XRD,FT-IR,Raman）results showed the succeddful synthesis of rGO and the better stability of rGO,and confirmed the GO,rGO were involved in the process of catalytic ozonation degradation of pollutants.In addition,the experimental results of the catalytic ozoantion degradation of atrazine（ATZ）,clofibric acid（CA）and idine（IOPA）showed that rGO displayed better catalytic activity and stability in the catalytic ozonation system,and the high stability of rGO was also confirmed in five recycling experiments.Furthermore,XPS analysis and radical inhibition experiments showed that oxygen-containing function groups（-OH,C=O）andπelectrons on the surface of rGO are the main reasons for the formation of hydroxyl radical,superoxide and single oxygen(^·OH,O₂^·-和¹O₂)in O₃/rGO system.（2）Using GO and Zn（NO₃）₂·6H₂O as precursors,a series of composites with different doping rations（x%rGO@ZnO）were synthesized by alkaline hydrothermal method.A series of characterizations and experimental results showed that the15%rGO@ZnO composite exhibited best catalytic activity(degradation rate reached100%,k_obs=0.4677min^-1),and under acidic conditions（p H=4）can also reach 98.87%removal rate,which mainly due to the suitable crystallinity of Zn O and the synergistic effect with rGO.Moreover,different experimental parameters were studied to determine the best experimental,and the results of cycle experiments showed the excellent stability of 15%rGO@ZnO.Furthermore,^·OH,O₂^·-and ¹O₂ were identified as the major reactive oxygen species.Overall,the 15%rGO@ZnO composites is demonstrated to be a highly efficient,stable,and recoverable catalyst,which provided a promising alternative in catalytic ozonation.