Synthesis Of Modified FeOCl And Application In Antibiotic Degradation

The frequent use of antibiotics in medicine,agriculture and animal husbandry has led to their entry into the environment through various pathways,causing environmental pollution as well as posing a great threat to public health,so it is crucial to adopt effective technical means to remove antibiotics from the environment.Fenton reaction is widely used as an effective treatment technology for various organics removal.Among them,the heterogeneous Fenton reaction system based on iron chlorine oxide（FeOCl）is one of the most promising organic degradation technologies due to its advantages of wide p H applicability and high catalytic activity,which has great potential for the removal of antibiotics from the environment.However,its catalytic activity is seriously affected by the low electron-hole separation rate between Fe²⁺/Fe³⁺redox cycles in the FeOCl structure.In addition,the insufficient Fe²⁺regeneration in FeOCl affects the practical application,and further improvement and optimization are needed in its application to antibiotic removal.Therefore,in this thesis,CNPs/FeOCl and ZIF-67/FeOCl composites were synthesized by hydrothermal and high-temperature calcination methods,respectively,taking advantage of materials such as CNPs（Carbon nitride polymers）and MOF（Metal-organic frameworks）to improve the individual FeOCl properties,and then applied them to antibiotic removal and explored the degradation mechanism.The main studies are as follows:（1）Enhanced catalytic degradation performance and mechanism of tetracycline hydrochloride by CNPs/FeOCl over a wide p H range.CNPs were prepared by hydrothermal method,and then CNPs/FeOCl complexes were successfully prepared by high-temperature sintering,characterized by XRD,FTIR and XPS,and finally applied to antibiotic degradation in aqueous environment（in the case of TC-HCl）.The experimental results showed that the CNPs/FeOCl complex had higher catalytic activity compared with that of FeOCl and CNPs alone.After 6 min of reaction（[TC-HCl]=20 mg/L,[CNPs/FeOCl]=0.2 g/L,[H₂O₂]=0.3m M,p H=3.5）,the removal efficiency of TC-HCl reached 100%.Meanwhile,the degradation efficiency of CNPs/FeOCl for TC-HCl could still reach more than 90%in the p H 3-11 range,where the antibiotics were almost completely degraded within 2 min at p H 5-9.Subsequently,four potential degradation pathways of TC-HCl were proposed by monitoring the TC-HCl intermediates during the catalytic reaction by high performance liquid chromatography-mass spectrometry（LC-MS）.The final ESR measurements showed that·OH was the main active species,while the active species burst experiments also indicated that·OH led to the degradation of TC-HCl.The above results,other antibiotic degradation and real sample simulations suggest that the constructed system has great potential to be applied to antibiotic removal in the environment.（2）ZIF-67/FeOCl bimetallic catalysts for efficient catalysis of ciprofloxacin and mechanism.The Co-based metal-organic framework ZIF-67 and FeOCl were selected as raw materials,and the ZIF-67/FeOCl catalysts with good dispersion were constructed by high-temperature calcination method using imidazolate skeleton（Zeolitic imidazolate framework,ZIF）as space carrier.The catalysts were characterized by SEM,FTIR and XPS.The results of ciprofloxacin（CIP）degradation experiments showed that ZIF-67/FeOCl（1:1）showed good catalytic ability in a wide p H range（p H 3.5-9）,and the degradation efficiency reached 86%within 14 min;meanwhile,the catalyst dosage,H₂O₂concentration,p H and inorganic ions all had effects on the degradation efficiency of CIP.The catalyst dosage,H₂O₂concentration,p H and inorganic ions all affected the degradation efficiency of CIP.The results of active species burst and ESR identification indicated that·OH was the main active species leading to CIP degradation.Subsequently,five possible degradation pathways of CIP were proposed by monitoring the intermediates of CIP during the catalytic reaction by LC-MS.The above results,other antibiotic degradation and real sample simulations indicate that the constructed system has great potential to be applied to antibiotic degradation in the environment.