Preparation Of Zinc MOF-derived Mesoporous Carbon For Adsorption Of Sulfamethoxazole In Water

With the rapid growth of antibiotic use and the harm of antibioticpollution,how to remove antibiotics from water has become a hot spot in research,and the current process of sewage treatment plants is difficult to completely remove antibiotics in water,resulting in antibiotics being discharged into the environment with water bodies,causing an increase in the level of environmental resistance genes.Adsorption method as a fast and efficient processing technology,due to the simple operation,no secondary pollution,wide application and other advantages are widely welcomed,as a commonly used adsorbent activated carbon adsorbent adsorbent adsorption performance is difficult to reproduce,low specific surface area utilization,high cost and other issues,metal-organic skeleton MOFs have the advantages of large specific surface area,aperture structure adjustable,topology diversity,etc.,so it has become a hot spot in the research.In this study,a MOF-based mesoporous material was designed for the antibiotic sulfamethoxazole,which can achieve efficient removal,and the main studies are as follows:1.Zinc MOF material ZIF-8 was prepared by room temperature stirring method,and the pore size adjustment effect of cetyltrimethylammonium bromide,sodium laurate and citric acid on zinc MOF-derived mesoporous carbon materials was explored.It was found that the adsorbent obtained by using cetyltrimethylammonium bromide and sodium laurate as template agents had the best adsorption effect.The preparation temperature,the type of template agent,the proportion of the template agent,and the post-treatment process were optimized.It was found that the adsorption effect of ZC-0.5 obtained in the condition of the molar ratio of the template agent to zinc was equal to 0.5,calcination at 800°C and pickling twice.The maximum adsorption amount of ZC-0.5 in the solution of 1mg·L^-1 sulfamethoxazole is 56.94 mg·g^-1.2.By XRD,SEM,nitrogen adsorption-desorption isotherms,FTIR,TGA and other analytical methods to characterize the properties and structure of the adsorbent,the total weight loss of the adsorbent under the calcination of material ZC-0.5 at a high temperature of 800°C is only 18.82%,which proves that the material has good thermal stability,and the XRD and FTIR analysis results show that the addition of template agents does not change the crystal structure and surface functional groups of the material,of which the BET specific surface area of the calculated material ZC-0.5 is 1459.73 m₂·g^-1,mesoporous pore size of 4.70 nm,total pore capacity of 0.9493 cm₃·g^-1,mesoporous proportion of 72.35%,compared with the original ZIF-8 specific surface area of 905.11m₂·g^-1,pore size of 1.64 nm,total pore volume of 0.3717cm₃·g^-1,mesoporous proportion of 14.22%,it proves that the pore size of the material was successfully adjusted by the template agent,increasing the mesoporous volume and specific surface area of the material.3.To explore the adsorption effect of ZC-0.5 on sulfamethoxazole under different conditions（temperature,pH,ionic strength,natural organic compounds,initial concentration of SMX,adsorption dose）,and to explore the effect of three factors（temperature,pH,ionic strength）on the adsorption process by response surface method,the optimal reaction conditions simulated by Box-Behnken were:303K,pH=4.13,Na Cl concentration of 0.4 g·L^-1,under this condition the adsorption amount is 60.6 mg·g^-1.4.The adsorption mechanism was studied,and the pseudo-second-order kinetic model,mixed 1,2-order（MOE）kinetic model was found to fit the experimental results very well through kinetic model fitting,and the Freundlich and Sips isotherms model in the isothermal fitting model were more in line with the adsorption effect of ZC-0.5 on sulfamethoxazole,and the adsorption thermodynamic calculation results showed that the adsorption process was spontaneous and endothermic entropy increase process.The adsorption mechanisms existing in the adsorption process are mainly pore size matching effect,hydrogen bonding,hydrophobic action,electrostatic interaction,π-πinteraction,etc.