Synthesis Of Modified ZIF-8 And Derived Porous Carbon Materials And Study On Their Adsorption Properties Of Tetracycline

Nowadays,the massive use of antibiotics has caused pollution of the water environment and residual water bodies,which has caused serious impacts on human health and the ecological environment,so it is necessary to remove them.Metal-organic framework materials(MOFs),as an organic-inorganic hybrid material,have large specific surface area and adjustable pore structure,and have been widely concerned by researchers at home and abroad.In this paper,tetracycline,which is common in antibiotics,is used as the research object to study the performance of metal-organic framework material ZIF-8 before and after modification and its derived porous carbon material as an adsorbent to remove tetracycline.The main work is as follows:(1)ZIF-8 and its derived porous carbon material(C-ZIF-8)adsorption of tetracycline in water;(2)ethylenediamine modified ZIF-8(NH₂-ZIF-8)and The research of its derivative porous carbon material(C-NH₂-ZIF-8)to adsorb tetracycline in water;the main contents are as follows:In this paper,zinc nitrate is used as the zinc salt,and 2-methylimidazole is used as the organic ligand.A certain amount of methanol is added as a solvent.The mixture is stirred at room temperature for a certain period of time(or a certain amount of ethylenediamine is added during the stirring process).After vacuum drying,ZIF-8 or NH₂-ZIF-8 material was obtained,and C-ZIF-8 or C-NH₂-ZIF-8 material was successfully prepared by direct carbonization,which was used for the adsorption of tetracycline in water.XRD,FTIR,TGA,N₂adsorption-desorption analysis,SEM characterization methods prove that the materials in this paper have been successfully synthesized,the carbonized materials can better maintain the skeleton structure of the raw materials and have a large specific surface area.Through the investigation of the carbonization temperature,it was found that the ZIF-8 material was carbonized at900?for 2h,and the material showed excellent tetracycline adsorption performance;the effect of the initial concentration and p H value of tetracycline during the adsorption of tetracycline by C-ZIF-8 was studied.The study found that when the initial concentration of tetracycline is 80mg/L,p H=6,the C-ZIF-8 material has the best adsorption effect on tetracycline,and the adsorption amount reaches about 220mg/g;C-NH₂-ZIF-8 is the same as above Under the conditions,the tetracycline also showed a higher adsorption capacity,the adsorption capacity reached 380mg/g,and the adsorption capacity was nearly double that of the C-ZIF-8 material.In order to study the adsorption effect and adsorption mechanism of the material,this paper conducted a kinetic study,and the research results show that the kinetics of C-ZIF-8 and C-NH₂-ZIF-8 adsorption of tetracycline are in line with the pseudo-second-order kinetic model;The adsorption isotherm data is in accordance with the Freundlich adsorption model,which shows that the process of C-ZIF-8 and C-NH₂-ZIF-8adsorption of tetracycline is mainly multi-molecular layer and chemisorption.Through thermodynamic studies,C-ZIF-8 and The process of C-NH₂-ZIF-8 adsorption of tetracycline is spontaneous.Finally,the recycling performance of C-ZIF-8 and C-NH₂-ZIF-8 materials was investigated,and it was found that C-ZIF-8 and C-NH₂-ZIF-8 materials can be effectively recycled,and after 3 times After circulation,C-ZIF-8 and C-NH₂-ZIF-8 still have high adsorption capacity for tetracycline.