Surface oxidation of activated electrospun carbon nanofibers and their adsorption performance for benzene, butanone and ethanol

• Activated electrospun carbon nanofibers were oxidized by acid treatment.
• Surface polarity of nanofibers increased with surface oxygen content increasing.
• Enhanced surface polarity led to higher water adsorption capacities on nanofibers.
• Surface oxidation improved the adsorption tendency for butanone over benzene.

Carbon nanofibers prepared by electrospinning and subsequent steam activation were oxidized by treatment in HNO3 and HNO3/H2SO4 mixture. Surface morphology and degree of graphitic structure of oxidized nanofibers are affected mildly by acid oxidation according to SEM and Raman measurement. Nitrogen adsorption/desorption isotherms demonstrate decrease in specific surface area and pore volume of carbon nanofibers after oxidation. XPS spectra exhibit that oxidized nanofibers possess higher surface oxygen content than pristine nanofibers. Higher water adsorption capacities on oxidized nanofibers determined by water adsorption isotherms suggest the improvement of surface polarity and hydrophilicity. Furthermore, adsorption isotherms of benzene, butanone and ethanol show that surface oxidation enhances the adsorption tendency for butanone and ethanol on nanofibers due to increased surface polarity, indicating that the adsorption selectivity to polar organic compounds is improved.

Surface oxidation of activated electrospun carbon nanofibers by treatment in acid enhanced the adsorption tendency for butanone relative to benzene, suggesting that the oxidized carbon nanofibers can be used as effective adsorbents for polar organic compounds.Figure optionsDownload as PowerPoint slide