Single-gas permeation experiments

A battery of single-gas permeation experiments using molecules with different kinetic diameters is used to gauge the effective pore size in defect-free membranes... 

Table 7.1 Experimental results from single gas permeation experiments...

For the experiments with silicon tetra-acetate (SiAc4), the experimental set-up as shown in Figure 3 was used. This apparatus can be used as a CVI reactor as well as a flow-controlled single-gas permeation apparatus. The permeance of the different gases is measured by setting a flow by MFC-3 and measuring the resulting pressure by the pressure indictor PI. 

Gas permeation experiments were carried out at 3()3 773K by using single or binary gas systems of hydrogen and nitrogen, etc. The membrane was fixed in a stainless steel(SS316) reactor placed in an electrical furnace. 

The permeation of gas mixtures through porous membranes provides more stringent test of the transport mechanism than the single gas permeation. If the transport occurs by the Knudsen diffusion, the selectivity based on the single gas experiments and that for the gas mixture should be equal. 

All parameters used in equations (1) and (2) were calculated from single gas adsorption and membrane permeation experiment. The numerical method for solving above equations were MOL(Method Of Line). These calculations were executed using LSODE solver(FORTRAN code). 

The present study adds some insight into the interactions between two polymers but, more importantly, illustrates the type of property behavior that can be expected from miscible or immiscible - but compatible - blends which exhibit macroscopically uniform physical properties. The solubility, diffusivity and permeability behavior of numerous series of blends have been evaluated between 1974 and 2012. Whether or not a single phase exists depends on the chemical structure, molar mass distribution, and molecular architecture of the components present. Water, organic solvents and gases have been used as probes in sorption experiments and transport processes incorporating pervaporation, vapor, and gas permeation. 

From single-gas experiments with permeabilities Pj (for preferentially permeating gas) and Pj, the ideal gas selectivity a - is calculated according to Equation 5, thereby, assuming that both gases i and j would not affect each other in their permeation behavior. 

Single-gas experiments of MIL-101 (Cr)/PSF membranes with CO2, CH4, and N2 at different MOF loadings showed increases in gas permeabilities with increasing MIL-lOl(Cr) weight percentage in PSF (Figure 8). CO2 is the preferentially permeating gas with permeability... 

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