Differential Heats of Adsorption of Nitrogen on Carbon Blacks

Qualitative assessment of the purity of multi-walled carbon nanotube samples using krypton adsorption

“…For nitrogen adsorption, only a slight hump is visible, whose amplitude increases when increasing the nanotubes content of the samples. A similar isotherm has been reported for long for the adsorption of N 2 on well graphitized surfaces and its shape is sometimes referred to as the Joyner-Emmet step [12]. It corresponds to the completion of the first adsorbed layer, which is progressive because adsorbed nitrogen is supercritical at 77 K [7].…”

Comparison of different methods for characterizing multi-walled carbon nanotubes

“…5b). Such a blunt step was already observed by Joyner and Emmet in the adsorption of N 2 on Graphon [15]. It has since been observed by several authors for the adsorption of N 2 on various well graphitized materials [16][17][18], and is usually referred to as the JE step.…”

On the isosteric heat of adsorption of non-polar and polar fluids on highly graphitized carbon black

“…Argon and nitrogen adsorptions on graphite are perhaps the most widely studied systems in the literature, where reliable isotherms and isosteric heats can be found [2][3][4][5][19][20][21][22][23][24][25]. Fig.…”

“…The amount of heat released per unit molecule added to the adsorbed phase at constant temperature and loading is commonly known in the literature as the isosteric heat (the correct thermodynamic term is the negative of the change in the enthalpy of adsorption [1]). Experimentally the isosteric heat can be measured with an adsorption calorimeter [2][3][4], or calculated using two adsorption isotherms which were measured at different (close enough) temperatures by Clausius-Clapeyron equation [5,6]. The experimental isosteric heat gives the overall heat released from the process [2][3][4][5][6], and its dependence on the extent of loading can provide insight into how molecules interact with various parts of the system as well with themselves.…”

“…Experimentally the isosteric heat can be measured with an adsorption calorimeter [2][3][4], or calculated using two adsorption isotherms which were measured at different (close enough) temperatures by Clausius-Clapeyron equation [5,6]. The experimental isosteric heat gives the overall heat released from the process [2][3][4][5][6], and its dependence on the extent of loading can provide insight into how molecules interact with various parts of the system as well with themselves. Together with computer simulation this can give detailed contributions of various interactions: fluid-fluid, fluid-basal plane and fluid-functional group [7,8].…”