Effective CO_2 Adsorption on Pristine and Chemically Functionalized MWCNTs

摘要

Carbon dioxide is one of the major greenhouse gases, which directly links to global warming. In this study, the laboratory produced multi-walled carbon nanotubes (MWCNTs) were amine-functionalized and tested for their potential as a CO_2 adsorbent material. The CVD grown MWCNTs were treated with H_2SO_4/HNO_3 and functionalized with 30% of 3-aminopropyltriethoxysilane (APTS). Both the pristine and functionalized MWCNTs were characterized for their surface morphology, chemical composition and functional groups by using FESEM, EDX and FTIR techniques. The acidic and APTS treatment to MWCNTs resulted in unbundling and loosening of the nanotubes from their bundled, agglomerated and entangled forms. Furthermore, oxidation and functionalization also significantly influenced the CO_2 adsorption capacity of MWCNTs. The breakthrough curves (adsorption isotherms) revealed that the modified MWCNTs exhibit higher capacity for CO_2 adsorption as compared to the pristine MWCNTs. Overall, CO_2 uptake by the pristine and modified MWCNTs was found about 0.00025 mol/g and 0.00038 mol/g, respectively.