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Partial isomorphic substitution of Zn in IRMOF metal clusters by cobalt ions is described for the first time. Specifically, different numbers of Co(2+) ions have been incorporated during solvothermal crystallization into the Zn-based MOF-5 (IRMOF-1) framework, which is one of the most studied MOF materials. The amount of Zn that can be substituted seems to be limited, being no more than 25% of total metal content, that is, no more than one Co atom inside every metal cluster formed by four transition-metal ions, on average. Several characterization techniques, including X-ray diffraction, DR UV-visible spectroscopy, N(2) adsorption isotherms, and thermogravimetrical analysis, strongly support the effective incorporation of Co into the material framework. As-synthesized CoMOF-5 has cobalt ions in octahedral coordination, changing to tetrahedral by simple evacuation, presumably by the removal of two diethylformamide molecules per Co ion. Moreover, the H(2), CH(4), and CO(2) uptake of MOF-5 materials systematically increases with the Co content, particularly at high pressure. Such an increase is moderate anyway, considering that Co is incorporated into unexposed metal sites that are less accessible to gas molecules.

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Experimental binary and ternary equilibrium data for the adsorption of hydrocarbon mixtures of methane, ethane, ethylene, and propylene on activated carbon at 20°C are presented and discussed. Reproduction of binary adsorption equilibria and prediction of ternary adsorption equilibria exclusively with data of binary systems have been carried out using a real adsorbed solution theory, which requires the calculation of the activity coefficients for the components in the adsorbed phase.Predicted equilibrium data are found to be in excellent agreement with experimental values using Wilson and UNIQUAC equations to calculate the activity coefficients. The real absorbed solution theory provides a much more accurate method for predicting multicomponent adsorption equilibria than the ideal adsorbed solution theory. SCOPEThe use of adsorption for the separation of gas mixtures has been continuously increasing. The main advantages of adsorption as compared with other separation techniques are the high selectivity that can be attained and the relatively high capacity of the adsorbents for volatile compounds, even at low partial pressures. Some applications of interest include the purification of methane, ethylene, and other light hydrocarbons; the covery of LPG from natural and refinery gas streams; the separation of olefins from cracked gases; and the recovery of acetylene and other pretrochemicals from dilute mixtures with other hydrocarbon gases.Although there are a great deal of publications on adsorption of mixtures of hydrocarbons on porous solids (Hill, 1949 On the other hand, most of the theoretical work based on the analogy between the thermodynamics of solutions and the thermodynamics of mixed adsorbates predicts adsorption equilibria using the assumption of an ideal behavior of the adsorbates on the solid surface, which can be expressed in terms of a Raoult's type law (Myers, 1965). However, predicted adsorption equilibria are not always found to be in good agreement with experimental data. Certainly, there is a competition of the adsorbed molecules for the active centers of the solid surface, due to the different adsorption capacity of the adsorbates, so that the ideal adsorbed solution theory can be improved modifying the Raoult's law by the introduction of the activity coefficients for the components in the adsorbed phase. This paper discusses new experimental data on adsorption for binary and ternary hydrocarbon mixtures on activated carbon at 20°C and a total pressure up to 760 mm Hg (101.33 K Pa). A thermodynamic method based on a real adsorbed solution theory is applied to reproduce experimental binary adsorption equilibria and to predict ternary adsorption equilibria, only with binary systems data, calculating the activity coefficients for the components in the adsorbed phase by means of Wilson and UNIQUAC equations for vapor-liquid equilibrium. CONCLUSIONS AND SIGNIFICANCEAn experimental technique based on a fluidized adsorbent bed can be used to determine adsorption equilibria of gaseous mixtures in por...

SBA-15 mesoporous materials were synthesized using the method reported by Zhao et al. Surfactant was removed from as-made materials by means of different techniques: thermal treatment under air atmosphere, solvent washing at different temperatures, and supercritical CO2 extraction in the presence and absence of cosolvents. The structure of resulting materials was characterized using conventional techniques: nitrogen and argon adsorption measurements, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR), and 29 Si MAS NMR. The efficiency of surfactant removal using CO2 under supercritical conditions is similar to that obtained by means of solvent washing under reflux but shows some improvements in the presence of cosolvents. Mesoscopic properties of mildtemperature solvent extracted SBA-15 materials depend on the efficiency of the surfactant removal and the use of supercritical CO 2 as solvent. Likewise, the size and volume of the complementary microporosity detected in the treated materials is closely related to the strategy of removal of hydrophilic poly(ethyleneoxide) chains of the triblock copolymer template occluded within the siliceous walls of the SBA-15 mesophase during the synthesis.

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The distribution of amino groups on amino-functionalized SBA-15 materials for CO 2 adsorption was studied by Transmission Electron Microscopy (TEM) in combination with a staining technique using RuO 4 in order to analyse the influence of the aminated organic chains location on the CO 2 adsorption properties. Mesostructured aminofunctionalized SBA-15 materials were obtained by co-condensation, grafting and impregnation using aminopropyl, AP (N), ethylene-diamine, ED (NN), diethylenetriamine, DT (NNN) and polyethyleneimine, PEI, as functionalizing agents. CO 2 adsorption isotherms of functionalized samples at 45 ºC showed that both the adsorption capacity (mg CO 2 /g ads) and the efficiency of amino groups (mol CO 2 /mol N) depend on the functionalization technique and the amount of organic compound used. While samples synthesized by co-condensation showed negligible CO 2 uptake and efficiency, adsorbents prepared by grafting and impregnation presented significant CO 2 adsorption capacities but a dissimilar efficiency. Key differences in the location of aminated chains explained the performance of CO 2 capture for every adsorbent, being grafted samples the adsorbents where amino groups were better distributed, favouring the CO 2 diffusion trough the whole structure.

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