The influence of geometric heterogeneity of closed carbon nanotube bundles on benzene adsorption from the gaseous phase-Monte Carlo simulations

Abstract

Benzene adsorption from the gaseous phase at 298 K and the thermodynamics of this process using Monte Carlo methods is studied. A series of closed single-walled carbon nanotube (SWCNT) bundles (triangular packing arrangement) with various distance between nanotubes is investigated. Isolated closed nanotube is treated as the reference system. Benzene is considered as a model compound to represent aromatics. Simulation results show the significant effect of the geometric heterogeneity on benzene adsorption as well as the enthalpy and entropy at low surface coverages. For insignificantly separated nanotubes and at low benzene uptakes, the entropy of the adsorbed phase is close to the entropy of solid benzene. Therefore, C 6 H 6 molecules strongly interacting with walls are ordered in quasi-solid structures. At higher surface coverages, the ordering and packing of benzene molecules is liquid-like. The geometry of bundles (mutual position of SWCNTs) significantly influences the position and orientation of adsorbed molecules against the wall.

Enthalpy–entropy compensation for isosteric state adsorption at near ambient temperatures

“…(12) in Barrer and Gibbons 1963b;Clark 1970, p. 39;Eq. (2.70) in Rouquerol et al 1999) where s G P � = s G � is for the standard state at temperature T; consequently, according to Gauden et al 2016;Kowalczyk et al 2017), we get:…”

“…(3) and (4), ∆H is the isosteric enthalpy of adsorption (∆H < 0 and q st = −ΔH), which is practically the same as the differential molar enthalpy [q diff = q st − RT Gauden et al 2016;Kowalczyk et al 2017), and this is…”

“…In the case of the tested system of solid phase and gas, the isosteric heat of adsorption in view of a is either: a. constant (Czepirski and Jagiełło 1989;Sircar et al 1999;Stadie et al 2012), b. monotonically decreasing (Burevski et al 1991;PeraTitus 2016;Zukal et al 2009;Terzyk et al 2016;Gauden et al 2016;Kowalczyk et al 2017;Czepirski and Jagiełło 1989;Sircar et al 1999;Stadie et al 2012;Barrer and Gibbons 1963a;Guo et al 2006), c. anomalous (increase and decrease) Gauden et al 2016;Kowalczyk et al 2017;Stadie et al 2012),…”

Endohedral and exohedral complexes of 1‐benzene with carbon nanotubes and high‐density assembly of multiple benzenes inside of a carbon nanotube

“…CNTs are an important carbon‐based adsorptive material with exceptional adsorption capabilities and high adsorption efficiency for various organic pollutants . CNTs are particularly promising as a benzene adsorbent for environmental protection/remediation . For example, in the study of Abbas et al CNTs impregnated with iron oxide nanoparticles were employed for the removal of benzene from water.…”

“…Elsehly et al investigated the performance of CNT‐based filter for benzene removal from aqueous solutions, and they indicated that the filters were efficient for benzene removal. Gauden et al studied the benzene adsorption on CNT bundles from gaseous phase using Monte Carlo methods, and showed the significant effect of the geometric heterogeneity on benzene adsorption.…”