Abstract
The surfaces of carbon molecular sieves (CMSs) were thermally fluorinated to adsorb water vapor. The fluorination of the CMSs was performed at various temperatures (100, 200, 300, and 400°C) to investigate the effects of the fluorine gas (F2) content on the surface properties. Fluorine‐related functional groups formed were effectively generated on the surface of the CMSs via thermal fluorination process, and the total pore volume and specific surface area of the pores in the CMSs increased during the thermal fluorination process, especially those with diameters ≤ 8 Å. The water vapor adsorption capacity of the thermally fluorinated CMSs increased compared with the as‐received CMSs, which is attributable to the increased specific surface area and to the semicovalent bonds of the C–F groups.
Highlights
Carbon dioxide (CO2) emission which is responsible for more than 60% of global warming has received worldwide concern
The functional groups introduced onto the surfaces of the Carbon molecular sieves (CMSs) were identified after examining the C1s and F1s X-ray photoelectron spectra (XPS) peaks after thermal fluorination, and the results are provided in Table 1 and Figure 1
The carbon content of the samples decreased remarkably by approximately 28%, and an increase in the fluorine content was observed after thermal fluorination
Summary
Carbon dioxide (CO2) emission which is responsible for more than 60% of global warming has received worldwide concern. Polymeric adsorbents, zeolites, silica gels, activated carbons, and molecular sieves have been extensively used as selective adsorbents because of their controllable pore structures and surface properties, which can be used to selectively capture CO2 [3, 4]. These adsorbate properties induce specific interactions with the adsorbent [13, 14] Various treatments, such as oxidation, amination, and fluorination, can be used to modify carbon surfaces to improve the adsorption of CO2 and water vapor [15,16,17,18,19,20]. Thermal fluorination altered the surface properties and pore structures of the CMSs and exhibited significant effects on the water vapor adsorption capacity. A mechanism is proposed for the improved water vapor adsorption capacity of CMSs after the thermal fluorination treatment
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