Study On The Preparation Of Modified Metal Foams And Catalytic Degradation Of Antibiotics In Water

With the rapid development of industry,agriculture and human production and life,the use of various types of antibiotics has increased significantly.Since most of the antibiotic drugs cannot be fully absorbed,the amount of antibiotics discharged into the water environment is increasing year by year.Antibiotics are highly stable and difficult to degrade,and are easily enriched in the environment,causing serious harm to the ecological environment.The advanced oxidation process based on persulfate has the advantages of strong oxidation capacity,wide p H applicability range and simple operation,which has obvious advantages for the treatment of difficult to degrade organic wastewater.However,persulfate needs to be activated and the existing activation catalysts suffer from difficulties in recovery and continuous operation.Therefore,in this thesis,two types of modified foam metal catalysts were synthesized by different methods using foam metal as a carrier and used for catalytic activation of persulfate to degrade typical antibiotics in water.The performance and influencing factors of its activated persulfate degradation of antibiotics were investigated,a possible catalytic reaction mechanism was proposed,and an experimental study on the continuous degradation of antibiotic pollutants was conducted.Details are as follows:（1）Carbon Co-coated nickel foam（CPH-Co/NF）catalysts with nanoflower structure were prepared by hydrothermal method using nickel foam as the carrier.The physical and chemical structures and compositional properties of the samples were analyzed by XRD,XPS,SEM,TEM and other characterization means.The results showed that the CPH-Co/NF catalyst had uniformly dispersed Co and C elements on the surface.The performance of this catalyst was examined for the degradation of oxyfluoroxacin（OFX）by activated PMS at different temperatures,p H,catalyst and peroxynitrite（PMS）addition in equal amounts,and the results showed that 20 mg/L OFX was degraded by 98.8%in 20 min under the optimized reaction conditions.Four cycling experiments were performed on the catalysts,which were found to have stable cycling performance and excellent environmental universality.The reactive oxygen species（ROS）produced by catalytic activation of peroxynitrite were mainly ¹O₂and·O₂^―,as revealed by the radical burst reaction and electron paramagnetic resonance（EPR）.The elemental composition and valence states on the catalyst surface before and after the reaction were analyzed by XPS,and the mechanism of catalytic PMS generation of ROS was postulated,and the possible mechanism of the degradation reaction was analyzed in combination with the detection of degradation intermediates by GC-MS.（2）The bimetallic sulfide catalysts（C-Co-Mn-S/NF）with dendritic structure were prepared by hydrothermal method using nickel foam as the carrier.The physical and chemical structures and compositional properties of the samples were analyzed by XRD,XPS,SEM,TEM and other characterization means.The results showed that the C-Co-Mn-S/NF catalyst had uniformly dispersed Co,Mn,S,O and C elements on the surface.The performance of the catalyst was examined for the degradation of sulfamethoxazole（SMX）by activated PMS at different temperatures,p H,catalyst and PMS addition in equal amounts,and the results showed that the 20 mg/L SMX was degraded 85%in 30min under the optimized reaction conditions.The catalysts were subjected to four cycles and were found to have stable cycling performance and excellent environmental universality.EPR revealed that the catalytically activated peroxynitrite produced ROS mainly as ¹O₂and·O₂^―.The elemental composition and valence states on the catalyst surface before and after the reaction were analyzed by XPS,and the mechanism of ROS generation from catalytic PMS was speculated,and the degradation intermediates were detected in combination with GC-MS to analyze the possible degradation reaction mechanism.