کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
635514 1456102 2011 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Investigating the potential of MgMOF-74 membranes for CO2 capture
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی تصفیه و جداسازی
پیش نمایش صفحه اول مقاله
Investigating the potential of MgMOF-74 membranes for CO2 capture
چکیده انگلیسی

MgMOF-74 is a metal–organic framework (MOF) with exposed metal cation sites that has one-dimensional 1.1 nm sized hexagonal-shaped channels. On the basis of information available in the published literature, it appears that MgMOF-74 has significant advantages over other MOFs, with respect to its uptake capacity for CO2. The primary objective of the present communication is to investigate the performance of MgMOF-74 membranes in separating CO2/H2, CO2/N2, CO2/CH4, and CH4/H2 mixtures, that are important in carbon capture. To achieve this objective all the parameters required for modeling MgMOF-74 membrane permeation were obtained using molecular simulations. Specifically, Configurational-Bias Monte Carlo (CBMC) simulations were used to determine pure component adsorption isotherms, and isosteric heats of adsorption. Molecular dynamics (MD) simulations were performed to determine the self-diffusivities, Di,self, and the Maxwell–Stefan (M–S) diffusivities, Ði, of guest molecules.The MD simulations show that the zero-loading diffusivity Ði(0) is consistently lower, by up to a factor of 10, than the values of the Knudsen diffusivity, Di,Kn. The ratio Ði(0)/Di,Kn is found to correlate with the isosteric heat of adsorption, which in turn is a reflection of the binding energy for adsorption at the pore walls. The stronger the binding energy, the lower is the ratio Ði(0)/Di,Kn.Using the Maxwell–Stefan formulation for binary mixture permeation, along with data inputs from CBMC and MD simulations, the permeation selectivities for CO2/H2, CO2/N2, CO2/CH4, and CH4/H2 mixtures were determined for a range of upstream pressures. The model calculations show that increased upstream pressures lead to significant enhancement in permeation selectivities; this enhancement is directly traceable to diffusional correlations within the 1D channels. Such correlations have the effect of slowing-down the more mobile partner species in the mixtures.MgMOF-74 membrane permeation selectivities for CO2/H2, and CO2/N2 mixtures are higher than those reported in the published literature with zeolite membranes.

Figure optionsDownload high-quality image (215 K)Download as PowerPoint slideHighlights
► The diffusivities in MgMOF-74 are significantly influenced by the binding energy of molecules.
► Diffusion selectivities are lower than Knudsen selectivity.
► Correlation effects increase with increased pressure.
► MgMOF-74 membranes have high permeation selectivities at increased pressures.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Membrane Science - Volume 377, Issues 1–2, 15 July 2011, Pages 249–260
نویسندگان
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