Re. Baltus, THE USE OF MOMENT THEORY TO INTERPRET DIFFUSION AND SIEVING MEASUREMENTS IN TERMS OF THE PORE-SIZE DISTRIBUTION IN HETEROPOROUS MEMBRANES, Journal of membrane science, 130(1-2), 1997, pp. 157-172
Moment theory has been applied to model porous membranes to show that
one can place reasonable bounds on the cumulative pore size distributi
on, the hindered diffusivity or the reflection coefficient of large so
lutes in a heteroporous membrane by measuring the diffusive permeabili
ty to a small solute, the hydraulic permeability and one or two additi
onal transport characteristics. These additional measurements involve
either the flux of a small solute at Pe similar to 1, the hindered dif
fusivity of a large solute or the reflection coefficient of a large so
lute at Pe>>1. Membrane heteroporosity is incorporated in the predicte
d bounds without requiring one to make any a priori assumptions about
the nature of the pore size distribution. in this paper, the results f
rom calculations performed with different model membranes containing l
og-normal pore size distributions are reported. A comparison of the re
sults obtained with three different membranes shows that one can disti
nguish between membranes with the same average pore size but different
pore size distributions by measuring either the hindered diffusion co
efficient or the reflection coefficient of two different sized solutes
. A comparison of the bounds on D and the bounds on sigma predicted fr
om different types of transport measurements shows that, under certain
conditions, one can place tighter bounds on one transport characteris
tic by measuring a different one.