Structural analysis of water and carbon tetrachloride adsorbed in activated carbon fibres

Abstract

We report X-ray diffraction studies of water and carbon tetrachloride adsorbed in nanoporous activated carbon fibres. The fibres are built of turbostratic nanoparticles separated by quasi two-dimensional voids, forming narrow slit-shaped pores. In order to determine the structure of water within the pores and its influence on the fibres' structure, mean interatomic and intermolecular distances have been estimated from the positions of the maxima of the normalized angular distribution functions obtained by X-ray diffraction. We observe a cluster arrangement of the water molecules, as well as significant changes in the interlayer distance of the carbon nanoparticles upon adsorption of both water and carbon tetrachloride. The results suggest that very high pressures arise within the pores, as has been observed in molecular simulations, and this may give rise to the large change in electronic properties of the fibres after adsorption of guest molecules. The in-pore pressure normal to the pore walls is estimated from the experimental data, and is found to be positive and of the order 4000 bar. Molecular simulation results for the normal pressure component are presented for both water and carbon tetrachloride in carbon slit pores, and are in general agreement with the experiments. For both fluids the normal pressure is an oscillating function of pore width.

Complex pole approach in thermodynamic description of fluid mixtures with small number of molecules

“…2). This result is in good correspondence with published data obtained in experiments and in simulations by molecular dynamics [18]. The developed theory was applied to obtain numerical solutions for the binary mixture with droplet potential energy taking account of both surface energy and miscibility energy (13).…”

“…Implementing Fisher assumptions for separate clusters we develop statistical theory for real mixtures with account of small-size effects. Our results agree with previously published experimental and theoretical results, in particular, we derive the expression for additional pressure, which exhibits oscillations in respect to the pore width [18]. It should be noted, that the study of partition sum in the complex plane was proposed in [19], as a tool to extend the definition of phase transitions to small systems.…”

“…In numerical modeling (Fig. 3) we focused at physically rich miscible case A chosen to be consistent with similar physical system in [18]. Then interaction of these clusters with cavity walls produces prominent peak feature at the figure.…”

Translational diffusion of water inside hydrophobic carbon micropores studied by neutron spectroscopy and molecular dynamics simulation

“…Such nano-confinement often gives rise to unusual physical properties, that are distinct from those in the bulk liquid [2][3][4]. In the case of water, nano-confinement suppresses crystallization altogether, modifying the water phase diagram and leading to a metastable supercooled liquid.…”

Chemically Driven Printed Textile Sensors Based on Graphene and Carbon Nanotubes

“…The d-spacing between two graphene layers in the GNP materials was estimated. The obtained value of 0.337 nm suggests that this is not a typical graphene (0.335 nm) [ 27 ] structure, while the enlarged distance between layers may result in structural defects that will increase the sensitivity to chemical stimuli.…”