Degradation Of Antibiotics By Carbon Nitride Modified By MOF Derivatives In Photoactivated Persulfate System

Antibiotics have made an indelible contribution to health care and agriculture since their introduction,but while they have been used extensively,a number of problems and hazards have gradually emerged.The misuse of antibiotics will not only cause damage to the internal organs and nervous system and disturbance to the normal flora,but also cause a series of problems such as"superbugs"and"resistance genes"over the past few years,which have created a more serious threat.The treatment of antibiotics in environmental water,the concentration of which is increasing every year,is an important part of the solution to antibiotic pollution.However,due to the stable nature and poor biochemical conditions of antibiotics themselves,they often fail to achieve the desired degradation effect based on traditional degradation methods,and the amount of antibiotics in the influent and effluent water is basically the same,making their pollution"pseudo-persistent".As a typical treatment method for dye and medical wastewater,the advanced oxidation process is based on Fenton reaction,and nowadays,the system based on activated persulfate has attracted much attention with stronger oxidative degradation performance,while the compound advanced oxidation system combined with photocatalysis presents higher catalytic activity and efficiency.Details of the study are as follows.（1）Carbon nitride（g-C₃N₄）materials are used as substrate materials for non-homogeneous catalysts based on their green and simple preparation for widespread applications in photocatalysis and their own photo-responsive properties.g-C3N4defects in structure（small specific surface area and pores）and catalysis（fast photogenerated electron-hole complexation and weak persulfate activation）are addressed by introducing Zn Co-PBA-derived Zn O/Co₃O₄（ZCC）bimetallic oxide was repaired.（2）A series of ZCC-SCN composite catalysts were prepared by hydrothermal and co-pyrolysis methods.The crystal structure,functional group characteristics and chemical composition of the catalysts were determined based on XRD,FTIR,XPS and other characterization methods,which confirmed the successful synthesis of the composite catalysts.The observed species in SEM and TEM can be found that the hydrothermally generated MOFs composite g-C₃N₄ achieved the simultaneous structural modification of both after pyrolysis.The porous MOFs derivatives and the exfoliated layers of g-C₃N₄ effectively expand the specific surface area and pore structure of the material,which is also effectively demonstrated by BET tests.（3）In terms of photo-response properties,UV-Vis diffuse reflectance spectrum（Uv-vis DRS）tests confirmed that the prepared ZCC-SCN catalysts have a broader color gamut of light absorption,while Photoluminescence Spectroscopy（PL）tests demonstrated that ZCC-SCN has a lower emission peak upon fluorescence activation,i.e.,a lower photogenerated carrier complexation rate.In the tests of electrochemistry,ZCC-SCN presented higher photocurrents.（3）It was studied that ZCC-SCN presented higher TC-HCl degradation performance in the photo-assisted persulfate system compared to the mono-system and g-C₃N₄.After dose optimization,88.65%degradation of TC-HCl could be achieved within 20 min,and the system had good p H adaptation and resistance to the interference of co-existing ionic organic matter.The mechanism analysis showed that the formation of heterojunction structure promoted the separation of photogenerated carriers,and the effective activation of persulfate.In the complex system,the joint participation of multiple radicals dominated by SO₄^·-and·O₂^-is the main reason for the efficient and rapid degradation of TC-HCl.This study provides new insights into the construction of MOF-derived modified g-C₃N₄ and its successful application to the advanced oxidation system of photo-assisted persulfate activation,which provides a new research direction to achieve the effective degradation of antibiotics.