Key words: adsorption, solubility, copper hexafluoroacetylacetonate, γ-alumina, supercritical fluid.
The data on the solubility of copper(II) hexafluoroacetylacetonate monohydrate Cu(hfa)2⋅H2O in carbon dioxide. The solubility increases with increasing temperature in the range of 303—353 K and a nonlinear increase in the solubility of Cu(hfa)2⋅H2O with increasing CO2 density in the supercritical (SC) range of parameters is observed. The dependence of solubility on the parameters of state (temperature, CO2 density) was described by the Chrastil equation. Adsorption of Cu(hfa)2⋅H2O from its solution in SCCO2 on three samples of γ-Al2O3, differing in the presence of acidic and basic additives, is studied. The adsorption isotherms have a shape characterized by a sharp rise in adsorption at the initial section. This shape indicates a high affinity of the complex to the carrier surface and/or its heterogeneity and the presence of high-energy adsorption centers. An increase in the CO2 density from 355 to 780 kg/m3 at a constant temperature (313 K) leads to a decrease in the adsorption of Cu(hfa)2⋅H2O on all three alumina samples. At the constant density of the medium 355 kg/m3 and the temperature rise from 313 to 343 K, a more complex behavior of the isotherms depending on the carrier characteristics and the range of concentrations of the adsorbed substance is observed.
doi:10.34984/SCFTP.2024.19.4.006