Removal Of Amoxicillin And Ciprofloxacin In Wastewater By Fe-based MOF Derived Material

The widespread use of antibiotics,especially their overuse and misuse,has sparked international concern.Antibiotics that are released into the environment may potentially cause contamination issues.In recent years,advanced oxidation technologies（Advance Oxidation Processes,AOPs）based on hydrogen peroxide（H₂O₂）and persulfate（PS）have been widely studied by researchers for the treatment of organic pollutants in wastewater.The research of heterogeneous AOPs catalysts based on Fe-based materials has gradually become a research hotspot of AOPs technology.In this study,the Fe-based metal-organic framework material MIL-88A-Fe was used as the precursor,and the MOF derivative material FMC was prepared by direct pyrolysis,with Amoxicillin（Amoxicillin,AMX）and Ciprofloxacin（Ciprofloxacin,CIP）as the target pollutants.The removal of AMX by the FMC/H₂O₂system and the removal of CIP by the FMC/PDS system have also been investigated,as well as the potential degradation mechanisms of AMX and CIP.The below are the key study observations and conclusions:（1）The MOF derivative material FMC was prepared by a simple pyrolysis method.FMC is an iron-carbon composite material in which zero-valent iron is wrapped in a carbon matrix structure.It was used to catalyze the degradation of AMX in simulated wastewater by H₂O₂.The FMC/H₂O₂system has the characteristics of high reaction activity,high catalytic efficiency and high degree of mineralization,and has good AMX removal and mineralization effects.The quenching experiment and electron paramagnetic resonance technology（EPR）in the reaction process confirmed that the FMC/H₂O₂system was a catalytic oxidation process that generates hydroxyl radicals（·OH）to oxidize and degrade AMX.The degradation intermediate products of AMX were identified by LC-MS analysis,and three potential degradation pathways of AMX were speculated:hydroxylation reaction,ring-opening reaction of the four-membered ring of-lactam,and stable product phenol hydroxypyrazine（m/z=188）was the representative degradation pathway AMX intermediate products are further oxidized and degraded to produce small molecular organics,or mineralized to form CO₂and H₂O.（2）The MOF-derived material FMC was used as the persulfate activator and applied to activate sodium persulfate to degrade CIP in the simulated wastewater.The experimental results showed that under the best reaction conditions,the initial concentration of 20 mg L^-1CIP was completely removed within 90 minutes,and the TOC removal rate reached 60.53%after 240minutes of reaction.Using quenching experiments and electron paramagnetic resonance（EPR）technology,it is confirmed that the FMC/PDS system was based on the oxidative degradation process that produces hydroxyl radicals（·OH）as the leading factor and accompanied by non-radical effects.The degradation by-products of CIP were analyzed by LC-MS analysis,and two possible degradation pathways of CIP were speculated:the degradation pathway represented by the hydroxylation reaction and the ring-opening reaction of the piperazine ring;the CIP intermediate products were further oxidized and degraded to produce small organic molecules,or mineralization to form CO₂and H₂O.