PREPARATION OF ACTIVATED CARBON FROM HAWTHORN SEED VIA TWO-STEP PYROLYSIS-CO2 ACTIVATION METHOD FOR ADSORPTION OF LOMEFLOXACIN FROM AQUEOUS SOLUTION
Activated carbon was prepared from hawthorn seed via a two-step pyrolysis-CO2 activation method.Pyrolysis of hawthorn seed and CO2 gasification of hawthorn seed char was investigated by thermogravimetric analysis coupled with Fourier transform infrared spectroscopy.The activated carbon was characterized by scanning electron microscopy,N2 adsorption-desorption,X-ray diffraction,Raman spectroscopy,and Fourier transform infrared spectroscopy.The adsorption behavior of the activated carbon for the removal of lomefloxacin from aqueous solution was investigated.Moreover,a novel adsorption bag was designed based on the activated carbon,and the adsorption bag suspended in water was applied for the removal of lomefloxacin.The results showed that pyrolysis of hawthorn seed mainly occurred between 230 and 420℃,leading to the release of CO2,acetic acid,furfural,and levoglucose.The dominant CO2 gasification process started at above 850 ℃.The surface area and total pore volume of activated carbon achieved 870 m2/g and 0.483 cm3/g,respectively,under the condition of 600 ℃ for carbonization temperature,120 min for carbonization time,900 ℃ for activation temperature,90 min for activation time,200 mL/min for CO2 flow rate.The adsorption isotherm of activated carbon for lomefloxacin followed the Langmuir isotherm model with the maximum monolayer adsorption capacity of 137 mg/g.The suspended adsorption bag effectively removed lomefloxacin from still water,and the adsorption kinetics followed pseudo-second kinetics model.