Enhanced flux through double-sided zeolite membranes

Microwave-assisted hydrothermal rapid synthesis of capillary MFI-type zeolite–ceramic membranes for pervaporation application

“…4 and Table 2 is that the double-sided membranes clearly outperform the single layer membranes. This effect was previously observed and explained by other authors [21], in relation with the effect of the support. Partial pressure drop across the support makes coverage higher on the downstream side of the zeolite membrane in the presence of a support, and lower driving forces result in lower fluxes.…”

“…Partial pressure drop across the support makes coverage higher on the downstream side of the zeolite membrane in the presence of a support, and lower driving forces result in lower fluxes. According to Gardner et al [21], the Maxwell-Stefan model indicates that, under specific conditions, the flux through supported zeolite membranes can be significantly higher when zeolite films are located on both sides of the porous support than for a single supported film. Consequently, for separations in which selectivity increases with zeolite thickness, double-sided membranes can yield fluxes and selectivities that are higher than those of single supported films.…”

“…Depositing films on both sides of the support can reduce the support influence for high loadings (out from the Henry regime). This fact makes feasible that permeance can be higher through a double-sided membrane even if the total thickness of the two films is greater than the thickness of a single film [21]. The support resistance reduces the flux of strongly adsorbed species, more strongly than that of weakly adsorbed species, so that a double-sided membrane can have higher flux and selectivity for binary mixtures in which the more strongly adsorbed component preferentially permeates.…”

“…The advantages of this strategy for increasing fluxes by limiting concentration polarization effects have been already discussed by Gardner et al [21].…”

Effect of external mass transport on permeation in a Wicke-Kallenbach cell

“…Sometimes, transport resistance in the membrane support layer is also considered to have influence and is included in the model (van de Graaf et al, 1998;de Bruijn et al, 2003). It is common to assume that the concentration is homogeneous in both compartments of the WK cell and thus a one-dimensional (1-D) model is generally applied (Jareman et al, 2004;Schlünder et al, 2006;Gardner et al, 2007). In some cases the membranes can be very thin such as for ultra-thin zeolite membranes (Hedlund et al, 1997(Hedlund et al, , 2002Burggraaf, 1999).…”