K₂CO₃ Modified Cigarette Butts-derived Porous Carbon For Chloramphenicol Adsorption In Water

With the rapid development of society,antibiotics have been widely used in our daily life,which not only facilitates human life,but also has a negative impact on our ecological environment.Chloramphenicol,a commonly used broad-spectrum antibacterial agent,is widely used in medical clinics,animal husbandry,aquaculture and other fields due to its effective bactericidal properties.Chloramphenicol has strong toxic side effects and has a great impact on our ecological environment.At present,the adsorption method has a good application prospect in antibiotic pollution due to its simple operation and recyclability,where the development of high-adsorption performance and low-cost adsorption materials is the key to the adsorption method.Cigarette butts,a common domestic solid waste,whose main component is cellulose acetate,can be used as a precursor for porous carbon adsorption materials.Therefore,this study selected waste cigarette butts as carbon precursor and potassium carbonate as modifier,and successfully prepared potassium carbonate modified cigarette butt-derived porous carbon KCBC.The adsorption behavior and adsorption mechanism of chloramphenicol on KCBC were investigated.Results showed that the KCBC modified with potassium carbonate has a smoother surface,a higher specific surface area(1421.27 m² g^-1)and a rich three-dimensional network microporous structure.The unmodified CBC basically did not adsorb chloramphenicol,while the modified KCBC showed good adsorption performance with the adsorption capacity for chloramphenicol being as high as 450.13 mg g^-1.In order to further study the adsorption behavior of chloramphenicol on KCBC,adsorption isotherms,adsorption kinetics,and adsorption thermodynamic models were used to fit the adsorption data.The adsorption isotherm results showed that the adsorption of chloramphenicol on KCBC was more in line with the Langmuir isotherm model,indicating that it belonged to the single molecular layer adsorption;the adsorption kinetics results showed that the pseudo-first-order and pseudo-second-order kinetic models could well explain the kinetic data,indicating that the adsorption of chloramphenicol on KCBC was affected by the combined effect of physical and chemical adsorption;the adsorption thermodynamic results showed that the adsorption process of KCBC on chloramphenicol was a spontaneous,endothermic,entropy-increasing reaction process.In addition,the adsorption capacity of chloramphenicol on KCBC decreased gradually with the increase of p H value and fulvic acid concentration.Although the presence of alkaline p H and fulvic acid was not conducive to the adsorption progress,the adsorption remained at a high level.The adsorption mechanism study showed that the adsorption of chloramphenicol on KCBC was mainly composed of physical adsorption（i.e.,pore filling and electrostatic interaction）and chemical adsorption（i.e.,π-πinteraction and hydrogen bond interaction）.The desorption and regeneration experiment proved that methanol could effectively elute chloramphenicol,and KCBC still maintained high adsorption performance after 5 cycles of recycling.Finally,several other common antibiotics（tetracycline hydrochloride,sulfamethoxazole,metronidazole,ciprofloxacin,etc.）were selected to verify the general applicability of KCBC,in this study,and the results showed that KCBC also exhibited excellent adsorption performance for other antibiotics.In conclusion,the excellent adsorption performance of KCBC provides a new idea for the resource utilization of waste cigarette butts and the treatment of wastewater containing antibiotics.