Thermophysical investigations of exfoliated graphite nanoplatelets and active carbon in binary aqueous environments at different temperatures

Abstract

Thermophysical investigations in binary liquid mixtures are important for many technological and environmental applications of exfoliated graphite nanostructures. The densities, speeds of sound, and refractive indices for the binary liquid mixture environments of water ? exfoliated graphite nanoplatelets, and water ? activated carbon have been measured versus composition, at different temperatures, at atmospheric pressure. The thermophysical properties such as the acoustic impedance, isentropic compressibility, specific refraction, space-filling factor, and relaxation strength have been evaluated over the composition range up to 100 kg m -3 , based on the experimental data. The absolute average percentage deviations of the calculated thermophysical properties in both systems were computed. The obtained results are discussed and interpreted in terms of molecular interactions and structural changes of these carbon-based nanomaterials.

A Thermodynamics Study on the Tetrahydrofuran Effect in Exfoliated Graphite Nanoplatelets and Activated Carbon Mixtures at Temperatures between 293.15 and 308.15 K

“…In the mixture of the AC dispersed in THF solvent, the THF molecules are limited at a single-layer structure on the surface of AC particles, possibly losing some of the solvent-solvent interaction energy, due to the smaller number of adjacent solvent molecules. e isentropic compressibility empirically estimated based on the obtained experimental data seems consistent, having the same sign in both studied binary mixtures [14].…”

“…It can be assumed that dipole-dipole interactions, dispersion forces, and hydrogen bonds are the most important forces that can appear between these unlike molecules [39]. e values of isentropic compressibility empirically evaluated [14], acoustic impedance, space-lling factor, speci c refraction, and relaxation strength were computed from experimental data. e computed physicochemical parameters in the xGnP + THF mixed binary solutions are presented in the same conditions in Table 6.…”

“…e initial compositions of the stock mixtures were prepared with an accuracy of ±0.2 kg•m −3 . More details about the refractive indices, speeds of sound, and densities experimental measurements and procedures can be found in previous papers [8,14,15]. e refractive index of the samples was measured with an Anton Paar GmbH Abbe automatic refractometer at a controlled temperature within ±0.01 K and a precision of ±0.000001.…”

“…e acoustical and optical thermodynamic properties such as isentropic compressibility (k S ), impedance (Z), space-lling factor (S), speci c refraction (r D ), and relaxation strength (r) at various temperatures and atmospheric pressure were estimated from experimental results of density, speed of sound, and refractive index. e calculation relations for the derived thermophysical properties have been described elsewhere [8,14,15]. Table 2.…”

A review of exfoliated graphite

“…Nanofluids involving dispersed GNP are attractive for ink-jet printing [127], electrophoretic deposition [127], environmental [128,129], and thermal [70,130] applications. GNP [131] is effective as a catalyst support.…”