University of Isfahan Gas Processing Journal 2322-3251 4 2 2016 08 01 Modifying functionalized-carbon-nanotube capacity to enhance water-vapor adsorption capacity from nitrogen gas 79 88 22153 10.22108/gpj.2017.100146.1003 EN Ahmad Freshtegan Department of Chemical Engineering, Collage of Engineering, University of Isfahan, Hezarjarib, Isfahan, Iran Mohamad Reza Talaie Department of Chemical Engineering, Shiraz University, Shiraz, Iran- Department of Chemical Engineering, Collage of Engineering, University of Isfahan, Hezarjarib, Isfahan, Iran S. Foad Aghamiri Department of Chemical Engineering, Collage of Engineering, University of Isfahan, Hezarjarib, Isfahan, Iran Ahmad Reza Khosropour Department of Chemistry, Collage of Science, University of Isfahan, Hezarjarib, Isfahan, Iran Journal Article 2016 11 16 The primary objective of this paper is to enhance the water-vapor-adsorption capacity of multiwall-carbon-nanotube (MWCNT) from nitrogen gas by grafting sulfonic acid groups and doping palladium nanoparticles into the adsorbent. MWCNT has been selected to be modified because of having homogeneous adsorption energy compared to silica gel. As a result, it is capable of creating isotherm having sharp rising zone which is an important feature for gas dehydration application. For this purpose, MWCNT functionalized by hydroxyl groups (MWCNT-OH) was utilized to produce MWCNT functionalized by sulfonic acid groups (MWCNT-OSO₃H), MWCNT-OH doped by palladium nanoparticles (MWCNT-OH-Pd) and MWCNT-OSO₃H doped by palladium nanoparticles (MWCNT-OSO₃H-Pd). Thermal and mass stability, Fourier-transformation infrared and atomic absorption analyses supported the fact that the functional groups and palladium nanoparticles were placed successfully throughout the carbon nanotubes. Then, the water-vapor adsorption isotherms of MWCNT-OH, MWCNT-OSO₃H, MWCNT-OH-Pd and MWCNT-OSO₃H-Pd were obtained at two temperatures of 15 and 24 ^oC. The water-vapor adsorption experiments revealed that by substituting sulfonic acid groups for the hydroxyl ones the adsorption of water vapor was enhanced only for higher gas humidity. However, by intercalating palladium nanoparticles into MWCNT-OSO₃H the capacity for water-vapor adsorption was improved for lower gas humidity as well. The obtained isotherms followed the isotherms type of V which is prevailing in water-vapor adsorption systems. https://gpj.ui.ac.ir/article_22153_4210c2d276067660a4385f31e554c4ea.pdf