Gino V. Baron

Free University of Brussels, Bruxelles, Brussels Capital Region, Belgium

Are you Gino V. Baron?

Claim your profile

Publications (217)513.16 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstracts: * AIChE 2014 COMOC-2 abstract final.docx (17.4KB) - Uploading Abstracts
    14 AIChE Annual Meeting; 11/2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Eight-membered ring (8 MR) zeolites hold large potential for industrial CO2 separation such as biogas separations. They offer large selectivity due to the constrained environment for adsorption, especially when large cations are present in the interconnecting windows [1-5]. The relatively small cages and windows of these zeolites increase the interaction strength between the adsorbent and CO2. At the same time, the diffusion of the slightly larger adsorbates CH4 and N2 through the 8 MR windows can be hindered. As a result, simulations predicted the highest CO2/CH4 selectivities in 8 MR structures among the different types of zeolites. [6] Experimental studies have mainly focused on the RHO, LTA, CHA and KFI structures up to now [7-12]. In the present work, the Rb- and Cs-exchanged ZK-5 zeolites (8 MR KFI type zeolites) were studied for kinetic CO2/CH4 separation. ZK-5 zeolites have the KFI structure, with a slightly higher Si/Al ratio (Si/Al = 3.6). It consists of a three-dimensional network of larger α- cages (11.6 Å in diameter) and smaller γ-cages (6.6 Å x 10.8 Å). The α- and γ-cages are connected through flat eight- membered rings with a diameter of 3.9 Å. A puckered eight-membered ring with a smallest diameter of 3.0 Å connects the γ-cages with each other. Rb-ZK-5 and Cs-ZK-5 were thoroughly characterized via chemical analysis, argon porosimetry, X-ray diffraction and Rietveld refinements. These refinements showed that a majority of the 8 MR sites were filled with cations. Afterwards, the CO2/CH4 separation potential of both adsorbents was assessed via the measurement of kinetic and equilibrium data (T = 261.15 - 323 K), adsorption and desorption breakthrough measurements at 303 K (P = 1 - 8 bar), and simulations of their performance at lab-scale and in a model pressure swing adsorption (PSA) process. The high occupation of the central 8 MR sites with large cations causes strong diffusional limitations for CH4 on Rb-ZK-5 and Cs-ZK-5. As a result, both zeolites effectively separate CH4 from CO2 with very high selectivities (α = 17). A disadvantage for Cs-ZK-5 is the occurrence of mass transfer limitations for CO2, yielding lower mass transfer coefficients on Cs-ZK-5 compared to Rb-ZK-5 and a large part of the bed being unused for separation. The global performance of both adsorbents will be compared to a benchmark 13X zeolite. Acknowledgements Tom Rmy and Leen Van Tendeloo acknowledge FWO- Vlaanderen for financial support. Joeri F.M. Denayer acknowledges FWO-Vlaanderen for the 1.5.280.11N research grant. Elena Gobechiya and Christine E.A. Kirschhock acknowledge the Belgian Prodex Office and ESA for financial support. Johan A. Martens and Christine E.A. Kirschhock acknowledge the Flemish Government for long-term structural funding, Methusalem. References 1. J. Shang, G. Li, R. Singh, Q. Gu, K. M. Nairn, T. J. Bastow, N. Medhekar, C. M. Doherty, A. J. Hill, J. Z. Liu and P. A. Webley, J. Am. Chem. Soc., 2012, 134, 19246-19253. 2. T. Remy, S. A. Peter, L. Van Tendeloo, S. Van der Perre, Y. Lorgouilloux, C. E. Kirschhock, G. V. Baron and J. F. Denayer, Langmuir, 2013, 29, 4998-5012. 3. M. M. Lozinska, E. Mangano, J. P. S. Mowat, A. M. Shepherd, R. F. Howe, S. P. Thompson, J. E. Parker, S. Brandani and P. A. Wright, J. Am. Chem. Soc., 2012, 134, 17628-17642. 4. T.-H. Bae, M. R. Hudson, J. A. Mason, W. L. Queen, J. J. Dutton, K. Sumida, K. J. Micklash, S. S. Kaye, C. M. Brown and J. R. Long, Energy Environ. Sci., 2013, 6, 128-138. 5. Q. Liu, T. Pham, M. D. Porosoff and R. F. Lobo, ChemSusChem, 2012, 5, 2237-2242. 6. R. Krishna and J. M. van Baten, J. Membr. Sci., 2010, 360, 323-333. 7. M. Palomino, A. Corma, J. L. Jorda, F. Rey and S. Valencia, Chem. Commun., 2012, 48, 215-217. 8. J. Zhang, R. Singh and P. A. Webley, Microporous Mesoporous Mat., 2008, 111, 478-487. 9. F. N. Ridha and P. A. Webley, Sep. Purif. Technol., 2009, 67, 336- 343. 10. J. Yang, Q. Zhao, H. Xu, L. Li, J. Dong and J. Li, Journal of Chemical & Engineering Data, 2012, 57, 3701-3709. 11. J. Yang, R. Krishna, J. Li and J. Li, Microporous Mesoporous Mat., 2014, 184, 21-27. 12. M. M. Lozinska, J. P. Mowat, P. A. Wright, S. P. Thompson, J. L. Jorda, M. Palomino, S. Valencia and F. Rey, Chem. Mater., 2014.
    14 AIChE Annual Meeting; 11/2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Eight-membered ring (8 MR) zeolites hold large potential for industrial CO2 separations such as biogas separation. They offer large selectivity due to the constrained environment for adsorption, especially when large cations are present in the interconnecting windows. The Rb- and Cs-exchanged ZK-5 zeolites (8 MR KFI type zeolites) were studied for kinetic CO2/CH4 separation. First, Rb-ZK-5 and Cs-ZK-5 were thoroughly characterized via chemical analysis, argon porosimetry, X-ray diffraction and Rietveld refinements. Afterwards, the CO2/CH4 separation potential of both adsorbents was assessed via the measurement of kinetic and equilibrium data (T = 261.15 - 323 K), breakthrough measurements at 303 K (P = 1 - 8 bar), and simulations of their performance. The high occupation of the central 8 MR sites with large cations causes strong diffusional limitations for CH4 on Rb-ZK-5 and Cs-ZK-5. As a result, both zeolites effectively separate CH4 from CO2 with very high selectivities (α = 17 at 1 bar and 303 K). Despite their very large CO2 selectivities, the performance of Rb-ZK-5 and Cs- ZK-5 was still lower than for the benchmark 13X zeolite on a larger scale. Future research needs to further unravel the adsorption mechanism on low-silica 8 MR zeolites and their corresponding potential in separation processes such as biogas purification.
    RSC Advances 11/2014; · 3.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this experimental study, the adsorption behavior of the ZIF-68 heterolinked zeolitic imidazolate framework has been explored. Vapor phase adsorption isotherms of linear C1-C6 alcohols, C6 alkane isomers, aromatics (benzene, toluene, xylene isomers, 1,3,5-trimethylbenzene and 1,3,5-triisopropylbenzene) and polar adsorbates (water, acetonitrile and acetone) are reported and discussed. The complex pore structure of ZIF-68, with two one-dimensional channels, each with a different polarity, displays an overall hydrophobic character. Its two-pore system results in S-shaped isotherms for small polar adsorbates (small alcohols, acetone and acetonitrile), while longer alcohols and nonpolar molecules, such as aromatics and C6 alkane isomers, lead to type I adsorption isotherms. Bulky molecules, with a kinetic diameter significantly larger than the pore windows, are adsorbed in large amounts, which gave reason to think that this ZIF-68 material has a certain degree of framework flexibility to enlarge the free aperture of the channels. Besides, diffusion coefficients from vapor phase uptake and infrared experiments point to a different adsorption mechanism for polar and nonpolar adsorbates. Liquid phase adsorption experiments demonstrated the separation of alcohol mixtures (ethanol/1-butanol) at low concentration from water, with a clear preference for 1-butanol.
    Langmuir : the ACS journal of surfaces and colloids. 06/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Due to the combination of metal ions and organic linkers and the presence of different types of cages and channels, Metal-Organic Frameworks (MOF) often possess a large structural and chemical heterogeneity, complicating their adsorption behavior, especially for polar-apolar adsorbate mixtures. By allocating isotherms to individual subunits in the structure, the ideal adsorbed solution theory (IAST) can be adjusted to cope with this heterogeneity. The binary adsorption of methanol and n-hexane on HKUST-1 is analyzed using this segregated IAST (SIAST) approach and offers a significant improvement over the standard IAST model predictions. It identifies the various HKUST-1 cages to have a pronounced polar or apolar adsorptive behavior.
    Langmuir : the ACS journal of surfaces and colloids. 06/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Zeolite crystals with cations present, such as ZSM-5, are widely used for gas sequestration, separations, and catalysis. One possible application is as an adsorbent to separate CO2 from N2 in flue gas mixtures. Typically, the zeolite framework is of a SiO2 composition, but tetravalent Si atoms can be replaced with trivalent Al atoms. This change in valence creates a charge deficit, requiring cations to maintain the charge balance. Experimental studies have demonstrated that cations enhance adsorption of polar molecules due to strong electrostatic interactions. While numerous adsorption studies have been performed for silicalite-1, the all-silica form of ZSM-5, fewer studies on ZSM-5 have been performed. Grand Canonical Monte Carlo simulations were used to study adsorption of CO2 and N2 in Na–ZSM-5 at T = 308 K, which is ZSM-5 with Na+ counter-ions present. The simulations suggest that a lower Si/Al ratio (or higher Na+ and Al content) substantially increases adsorption at low pressures. At high pressures, however, the effect of the Al substitutions is minor, because the Al−/Na+ sites are saturated with guest molecules. Similarly, a lower Si/Al ratio also increases the isosteric heat of adsorption at low loading, but the isosteric heats approach the silicalite-1 reference values at higher loadings. Comparison of simulations and experimental measurements of the adsorption isotherms and isosteric heats points to the importance of carefully considering the role of charge on the Na+ cations, and suggest that the balancing cations in ZSM-5, here Na+, only have partial charges.
    Adsorption 01/2014; · 1.55 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract
    Microporous and Mesoporous Materials 01/2014; 183:143-149. · 3.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Zeolitic Imidazolate Frameworks (ZIFs) are crystalline microporous materials, consisting of transition metals (M = Co, Cu, Zn, etc.) linked by imidazolate (Im) or functionalized Im ligands. This subfamily of the Metal-Organic Frameworks (MOFs) displays good chemical and structural stability, which make them attractive as separation media in liquid phase separations. ZIF-68 is an interesting member of this family, with a complex pore structure consisting of two one-dimensional channels formed by three different types of cages. The small channel is composed of alternating small and medium cages, while the large channel comprises the large cages [1]. In the present work, the adsorption behavior of ZIF-68 is studied via vapor phase kinetic and equilibrium experiments with C1-C6 alcohols and other organic compounds (acetone, acetonitrile, C6-isomers, tri-isopropylbenzene) and kinetic batch experiments of alcohol mixtures in water. S-shape isotherms are obtained for polar adsorbates (fig.1), which is related to (1) the presence of two chemically different channels in the ZIF-68 framework and (2) the rather apolar nature of the material, which results in unfavorable adsorption of polar compounds at low concentration. Depending on the component, the adsorption capacity varies between 0.25 and 0.30 g/g. A comparison to the Argon isotherm indicated that both types of channels of ZIF-68 are densely filled with the different organic compounds. Uptake of the different alcohols occurs slowly on the large crystals (around 70 m) used in this study. Moreover, two different diffusion regimes can be observed, in which molecular transport in the two-pore systems occurs at different rates. Besides, it was observed that bulky molecules, with a kinetic diameter significantly larger than the pore windows, are adsorbed in large amounts, which gave reasons to think that also this ZIF material, just as ZIF-7 [2] and ZIF-8 [3-5], has a certain degree of structural flexibility to enlarge the free aperture of the channels, enhancing the diffusion process. Liquid phase experiments indicate the potential of ZIF-68 in the selective uptake and separation of alcohol/water mixtures. Fig.1: Adsorption isotherms of C1-C6 alcohols, acetone and acetonitrile at 50 C. References [1] R. Babarao, S. Dai and D. Jiang, J. Phys. Chem. C 115 (2011) 81268135 [2] C. Gcyener, J. van den Bergh, J. Gascon and F. Kapteijn, J. Am. Chem. Soc. 132 (2010) 17704-17706 [3] S.A. Moggach, T.D. Bennett and A.K. Cheetham, Angew. Chem. 121 (2009) 7221-7223 [4] D. Fairen-Jimenez, S.A. Moggach, M.T. Wharmby, P.A. Wright, S. Parsons and T. Dren, J. Am. Chem. Soc. 133 (2011) 8900-8902 [5] J.C. Saint Remi, T. Rmy, V. Van Hunskerken, S. Van der Perre, T. Duerinck, M. Maes, D.E. De Vos, E. Gobechiya, C.E.A. Kirschhock, G.V. Baron and J.F.M. Denayer, ChemSusChem 4 (2011) 1074-1077. Acknowledgements The authors are grateful to the Agency for Innovation by Science and Technology in Flanders (IWT) for support in the SBO MOFshape project.
    13 AIChE Annual Meeting; 11/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Porous materials such as metal-organic frameworks offer great potential for separation technologies. Over the past decade the synthesis of a large number of new structures has been reported but relatively little attention has been given to the application of these novel adsorbents as stationary phases in gas or liquid chromatography. In this work, we report on the potential of the metal-organic framework UiO-66 for the separation of cyclic isomers. The extremely high preferential retention of cyclic hydrocarbons of the aromatic’s and functionalized cycloalkane’s type is exploited to achieve difficult separations. Confinement effects play a crucial role in fine-tuning the adsorbent’s properties.
    Microporous and Mesoporous Materials 08/2013; · 3.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This work discusses the adsorption of polar and apolar molecules on the copper?benzene-1,3,5-tricarboxylate (Cu?BTC) metal?organic framework. Vapor phase adsorption isotherms of various polar adsorbates such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-hexanol, water, acetone, acetonitrile, tetrahydrofuran, and N,N-dimethylformamide, as well as some apolar adsorbates such as n-hexane, n-heptane, m-xylene, and cyclohexane, on the Cu?BTC framework are presented. We show that water exposure of the Cu?BTC framework has an adverse effect on the uptake capacity. However, with minimized water exposure, we find high adsorption capacities, exceeding 0.65 cm3/g for all adsorbates with the exception of water, and we show that small polar adsorbates exhibit a two-step adsorption behavior. This behavior is further studied using molecular simulation and proposed to occur due to the presence of the various Cu?BTC cages. The cages containing the exposed coordinatively unsaturated copper sites have a more
    The Journal of Physical Chemistry C 08/2013; 117(35):18100-18111. · 4.84 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: doi: 10.1021/jp402294h
    The Journal of Physical Chemistry C 05/2013; 117(24):12567-12578. · 4.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Selective separation of CO2 is becoming one of the key technologies in the (petro-) chemical industry. This study focuses on the adsorption and separation of CO2 from CH4 on a new low-silica (LS) type of the eight-membered ring KFI zeolite. A series of alkali (Li, Na, K) and alkaline-earth (Mg, Ca, Sr) exchanged samples of the new LS KFI were synthesized and characterized. LS Li-KFI showed the largest pore volume whereas LS Na-KFI and LS K-KFI were inaccessible for Argon at 87 K. Adsorption of CO2 at 303 K demonstrated the dominant quadrupolar interaction on alkali exchanged LS KFI samples. LS Li-KFI showed the largest capacities upon high pressure isotherm measurements of CO2 (4.8 mmol/g), CH4 (2.6 mmol/g) and N2 (2.2 mmol/g) up to 40 bar at 303 K. The performance of the new LS KFI was compared to a KFI sample (ZK-5) with a higher Si/Al ratio. Isotherm measurements and dynamic breakthrough experiments demonstrated that ZK-5 samples show larger working capacities for CO2/CH4 separations at low pressure. Li-ZK-5 and Na-ZK-5 show the highest capacities and high selectivities (similar to benchmark 13X).
    Langmuir 03/2013; · 4.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dynamic adsorption–desorption measurements of CO2 and CH4 in amino-MIL-53(Al) were carried out in an adsorption breakthrough setup at different temperatures (303, 318, and 333 K) and pressures (1, 5, and 30 bar) to study the desorption dynamics of CO2 in amino-MIL(Al) as it plays an important role in the design of pressure swing adsorption (PSA) process for the upgrading of biogas. 13X zeolite was used as a reference material. The dynamic adsorption selectivity as well as the desorption efficiency of CO2 in both amino-MIL-53(Al) and 13X zeolite were calculated to evaluate the potential of amino-MIL-53(Al) for the upgrading of biogas by PSA process.
    Adsorption 01/2013; · 1.55 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Separation of styrene (ST) from ethylbenzene (EB) remains an industrially relevant challenge in the production of polystyrene. Adsorptive separation with metal–organic frameworks (MOFs) is a potential alternative for the conventional vacuum distillation process. Adsorption and separation of ST and EB on the MOFs MIL-47 and MIL-53(Al) were studied under vapor-phase conditions. ST and EB show traditional type I isotherms on MIL-47. Contrarily, ST adsorption isotherms show steep steps on MIL-53(Al) as a result of the breathing of the flexible MOF upon increased adsorbate pressure. The separation potential of both MOFs was investigated by performing vapor-phase breakthrough experiments at total hydrocarbon partial pressures between 1.14 and 16.4 mbar and temperatures between 35 and 90 °C. ST is preferentially adsorbed on both MOFs. Although the MOFs are isostructural, the evolution of selectivity with temperature and pressure is different for both materials due to the different interaction and separation mechanisms.
    Industrial & Engineering Chemistry Research. 11/2012; 51(45):14824–14833.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The low coverage adsorptive properties of the MIL-47 metal organic framework toward aromatic and heterocyclic molecules are reported in this paper. The effect of molecular functionality and size on Henry adsorption constants and adsorption enthalpies of alkyl and heteroatom functionalized benzene derivates and heterocyclic molecules was studied using pulse gas chromatography. By means of statistical analysis, experimental data was analyzed and modeled using principal component analysis and partial least-squares regression. Structure-property relationships were established, revealing and confirming several trends. Among the molecular properties governing the adsorption process, vapor pressure, mean polarizability, and dipole moment play a determining role.
    Langmuir 09/2012; 28(39):13883-91. · 4.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel catalyst design for the conversion of mono- and disaccharides to lactic acid and its alkyl esters was developed. The design uses a mesoporous silica, here represented by MCM-41, which is filled with a polyaromatic to graphite-like carbon network. The particular structure of the carbon-silica composite allows the accommodation of a broad variety of catalytically active functions, useful to attain cascade reactions, in a readily tunable pore texture. The significance of a joint action of Lewis and weak Brønsted acid sites was studied here to realize fast and selective sugar conversion. Lewis acidity is provided by grafting the silica component with Sn(IV), while weak Brønsted acidity originates from oxygen-containing functional groups in the carbon part. The weak Brønsted acid content was varied by changing the amount of carbon loading, the pyrolysis temperature, and the post-treatment procedure. As both catalytic functions can be tuned independently, their individual role and optimal balance can be searched for. It was thus demonstrated for the first time that the presence of weak Brønsted acid sites is crucial in accelerating the rate-determining (dehydration) reaction, that is, the first step in the reaction network from triose to lactate. Composite catalysts with well-balanced Lewis/Brønsted acidity are able to convert the trioses, glyceraldehyde and dihydroxyacetone, quantitatively into ethyl lactate in ethanol with an order of magnitude higher reaction rate when compared to the Sn grafted MCM-41 reference catalyst. Interestingly, the ability to tailor the pore architecture further allows the synthesis of a variety of amphiphilic alkyl lactates from trioses and long chain alcohols in moderate to high yields. Finally, direct lactate formation from hexoses, glucose and fructose, and disaccharides composed thereof, sucrose, was also attempted. For instance, conversion of sucrose with the bifunctional composite catalyst yields 45% methyl lactate in methanol at slightly elevated reaction temperature. The hybrid catalyst proved to be recyclable in various successive runs when used in alcohol solvent.
    Journal of the American Chemical Society 05/2012; 134(24):10089-101. · 10.68 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The NH(2)-MIL-53(Al) metal-organic framework was studied for its use in the separation of CO(2) from CH(4), H(2), N(2)C(2)H(6) and C(3)H(8) mixtures. Isotherms of methane, ethane, propane, hydrogen, nitrogen, and CO(2) were measured. The atypical shape of these isotherms is attributed to the breathing properties of the material, in which a transition from a very narrow pore form to a narrow pore form and from a narrow pore form to a large pore form occurs, depending on the total pressure and the nature of the adsorbate, as demonstrated by in situ XRD patterns measured during adsorption. Apart from CO(2), all tested gases interacted weakly with the adsorbent. As a result, they are excluded from adsorption in the narrow pore form of the material at low pressure. CO(2) interacted much more strongly and was adsorbed in significant amounts at low pressure. This gives the material excellent properties to separate CO(2) from other gases. The separation of CO(2) from methane, nitrogen, hydrogen, or a combination of these gases has been demonstrated by breakthrough experiments using pellets of NH(2)-MIL-53(Al). The effect of total pressure (1-30 bar), gas composition, temperature (303-403 K) and contact time has been examined. In all cases, CO(2) was selectively adsorbed, whereas methane, nitrogen, and hydrogen nearly did not adsorb at all. Regeneration of the adsorbent by thermal treatment, inert purge gas stripping, and pressure swing has been demonstrated. The NH(2)-MIL-53(Al) pellets retained their selectivity and capacity for more than two years.
    ChemSusChem 02/2012; 5(4):740-50. · 7.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Adsorption properties of linear and branched (C5–C9) alkanes were studied on the mesoporous materials MCM-41, MCM-48, PHTS and SBA-15 in the 75–195 °C temperature range. Adsorption enthalpies at zero coverage and Henry constants were measured by gas phase chromatography. The experimental data was statistically investigated and used for modeling. Quantitative structure activity/property relation models were established relating structural descriptors of adsorbate and adsorbent to adsorption properties using partial least square regression. It was shown that the presence of micropores leads to an increase in Henry constants and adsorption enthalpies but does not induce shape selectivity. Excellent agreement is found between experimental and modeled adsorption properties. In depth analysis reveals influence of the degree of branching but not the position of the branching for these materials.
    Chemical Engineering Journal 01/2012; 179:52-62. · 3.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: T. Remy, S. Van Der Perre, Y. Lorgouilloux, C.E.A. Kirschhock, J.A. Martens, G.V. Baron, J.F.M. Denayer CO2 separations with KFI zeolites Several options exist to separate industrial gas mixtures: cryogenic distillation, membranes, absorption or selective adsorption. Selective separation of CO2 plays an important role within the current issues about global warming and CO2 mitigation. Typically CO2 is being removed from gas streams, via amine stripping which is a process with significant drawbacks. Adsorptive or membrane processes are interesting alternatives for CO2/CH4 and CO2/N2 separations. The potential of cation-exchanged KFI zeolites (K-KFI, Li-KFI and Ca-KFI) for these processes has been investigated in this study. The KFI structure consists of a three-dimensional network of two larger a-cages (diameter 11.6 ) and six smaller g-cages (6.6 x10.8 ) per unit cell. The cavities are connected with each other through eight-membered rings with a diameter of 3.9 . Adsorption isotherms of CO2, CH4 and N2 were recorded using the gravimetric technique on K-KFI, Li-KFI and Ca-KFI zeolites at 303 K. CO2 adsorption isotherms are of type I, with a capacity amounting to 4-4.5 mmol/g depending on the cation present. The uptake measurements indicate much lower affinity for CH4, with a low diffusion through the small 8-membered windows. Water vapour isotherms measured at 313 K indicate a large affinity for water, with a capacity of about 8.5 mmol/g. The dynamic separation potential was assessed via breakthrough measurement at 308 K for CO2/CH4 and CO2/N2 (P = 1 bar) and different compositions in order to record the binary isotherm under these conditions. As a result of the limited diffusion of CH4 and the lower affinity for this component, almost immediate breakthrough of methane is observed. In these dynamic conditions, also CO2 uptake is hindered by diffusion, resulting in broadened breakthrough profiles. The influence of water was investigated by altering the relative humidity from 0 to 20%.
    2011 AIChE Annual Meeting; 10/2011
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Adsorption properties of MIL-47 were measured by pulse gas chromatography between 180°C and 250°C for a set of 20 hydrocarbons consisting of aromatic compounds and heterocyclic molecules. The adsorption enthalpy and Henry constants (K') were determined at zero coverage; van 't Hoff plot correlations (r²) were above 0.99 in all cases. In general, good correlations between adsorption enthalpies and Henry constants were found. Trends of unsaturated bonds' presence, molecular size and presence of hetero-atoms can be observed in the experimental data (e.g. Henry constants, retention time, entropy contribution...). Strong influence of the adsorbates' polarizability and electronegative character is observed when hetero-atoms are present. The latter can be related to the interaction with the metal clusters. For a series of benzene alkyl derivates a linear trend is observed. For each additional carbon added, the adsorption enthalpy deceases stepwise: -6.2 kJ/mol for the benzene, toluene, ethyl benzene and propyl benzene series, -6.1 kJ/mol for the benzene, toluene, xylenes and mesitylene series. Statistical data analysis was applied to model zero coverage adsorption enthalpy and Henry constants. The objective was to establish quantitative structure property relationship (QSPR) models that could qualitatively and quantitatively describe the adsorption properties in the gas phase on this Metal Organic Framework. Principal component analysis is used to divide the experimental data set in a training set (model establishing) and external validation set, using a large descriptor set containing physicochemical and structural parameters of the adsorbates. The descriptor set was reduced by elimination of highly correlated descriptors. Partial least square regression was performed in order to obtain linear models using small descriptor sets containing some structural descriptors and physicochemical properties of the adsorbate molecules. A bootstrap methodology was used to further eliminate non-relevant descriptors on the likeliness of a descriptor coefficient being equal to zero. The number of bootstraps was set to 500.
    AIChE 2011 Annual Meeting; 10/2011

Publication Stats

1k Citations
513.16 Total Impact Points

Institutions

  • 1970–2014
    • Free University of Brussels
      • Department of Chemical Engineering (CHIS)
      Bruxelles, Brussels Capital Region, Belgium
  • 2000–2007
    • KU Leuven
      • Centre for Surface Chemistry and Catalysis (COK)
      Leuven, VLG, Belgium