Preparation Of Biomass Porous Carbon Materials And Study On Adsorption Properties For Sulfadiazine

Sulfonamide antibiotics（SAs）are broad-spectrum antibacterial drugs that are often used to treat infectious diseases.At the same time,SAs are stable in nature and not easy to degraded in the environment,and their repeated use has caused SAs to accumulate in water for a long time,destroying the ecological balance and causing harm to humans and the environment.The adsorption method has developed into the most commonly used method to remove SAs residues in water because of its advantages such as lower energy consumption,convenient operation,no excess products and reusable adsorbents.In order to solve the shortcomings of traditional adsorbents such as high price,low adsorption capacity,poor selectivity,low yield and complex production process,the adsorbent with high adsorption performance was obtained by using biomass with wide sources and low price as carbon precursor.In this paper,sulfadiazine（SD）in water is mainly selected as the research object of the adsorbent.Three kinds of biomass rich in carbon and oxygen,such as microcrystalline cellulose（MCC）,orange peel and carrot,were used as carbon precursors,and different porous carbon materials were obtained by pyrolysis at high temperature,and their characterization and adsorption properties were studied.The experimental research results are as follows:（1）Porous carbon materials（MCPC-x）was obtained by physical activation with MCC as carbon precursor.Scanning electron microscope（SEM）,transmission electron microscope（TEM）,specific surface area analyzer（BET）,and Fourier infrared spectroscopy（FT-IR）were used to evaluate the overall appearance structure,pore structure,specific surface area,surface functional groups,etc.characterization analysis.The analysis result is that the specific surface area and porosity of MCPC-x are related to the amount of tetraethyl orthosilicate（TEOS）.When the amount of TEOS is 1 m L,the specific surface area and total pore volume of the carbon material are the largest,which are 797 m²g^-1and 0.22 cm³g^-1,respectively.（2）With orange peel as carbon precursor,1-hexadecyl-3-methylimidazolium bromide([C₁₆Mim]Br)as nitrogen precursor,and oxidizing gas as activator,a nitrogen-containing porous carbon material was obtained by physical activation（N-PCs-y）.The overall appearance,specific surface area,pore structure,element content and number of functional groups were analyzed by SEM,BET and X-ray photoelectron spectroscopy（XPS）.The analysis result is that the specific surface area and porosity of N-PCs-y are related to the pyrolysis temperature.When the pyrolysis temperature is 800°C,the specific surface area and total pore volume of the carbon material are the largest,which are 1146 m²g^-1and 1.6 cm³g^-1,respectively.（3）With carrot as carbon precursor and Na₂SiO₃·9H₂O as hard template,nitrogen-containing porous carbon material（N-HPCs-x）was prepared by grinding process.The overall appearance,specific surface area,pore structure,element content and number of functional groups were analyzed by SEM,BET and XPS.The results show that the specific surface area and porosity of N-HPCs-x are related to the ratio of Na₂SiO₃·9H₂O to carrot.When the ratio of Na₂SiO₃·9H₂O to carrot is 0.2:1,the specific surface area and total pore volume of the carbon material are the largest,which are 1265 m²g^-1and 2.1 cm³g^-1,respectively.（4）The adsorption performance and recycling properties of MCPC-1,N-PCs-800 and N-HPCs-0.2 were studied with SD as the target.At a temperature of 298 K,the maximum monolayer adsorption capacities of MCPC-1,N-PCs-800 and N-HPCs-0.2 were 172.7 mg g^-1,244.5 mg g^-1and 301.0 mg g^-1,respectively.In comparison,the Langmuir model and the pseudo-second-order kinetic model can better explain that the adsorption of SD by MCPC-1,N-PCs-800 and N-HPCs-0.2 belongs to favorable adsorption.Thermodynamic analysis results showed that the process was spontaneous,exothermic and the chemical adsorption was main adsorption process.The main adsorption mechanisms in the adsorption process are pore capture,hydrophobic interactions,π-πdonor-receptor interaction,hydrogen bonding interactions,and electrostatic interactions.