Permoporometric study on ultrafiltration membranes

Why liquid displacement methods are sometimes wrong in estimating the pore‐size distribution

“…(3) The pores all have a length l, where l is usually taken to be the thickness of the membrane (or the thickness of the membrane skin layer in the case of an asymmetric membrane) (Capannelli et al, 1983;Munari et al, 1989). With assumption 2 (parallel pores), and the implicit assumption that nowhere in the measuring setup is a resistance against flow present, the transmembrane pressure at which the liquid in a pore is displaced is equal to the critical pressure of that pore.…”

“…Although many researchers investigated the liquid displacement method and improvements were suggested (Piatkiewicz et al, 1999;Vaidya and Haselberger, 1994;Wienk et al, 1994), no one studied how the pore size distribution determination is affected by pore connections (that is, if the pores are not straight through the whole membrane layer). Nevertheless, the method is not only used to determine the pore size distribution of membranes with straight-through pores (Jakobs and Koros, 1997;Kujawski et al, 1989;Munari et al, 1985Munari et al, , 1989, but also for symmetric membranes and asymmetric membranes with a thin skin layer characterized by more or less interconnecting pores (Bottino et al, 1991(Bottino et al, , 1994Capannelli et al, 1983;Mikulášek and Dolecek, 1994;Munari et al, 1985).…”

Characterization of meso- and macroporous ceramic membranes in terms of flux measurement: A moment-based analysis

“…Only pores active to permeation are detected [14][15][16][17] It requires knowledge of contact angles Liquid and gas flux measurement Liquid and gas permeabilities are monitored as a function of the pressure drop across the membrane…”

“…It is generally accepted that a real PSD in porous membranes follows a log-normal distribution [17,20]. In this case, the flux pattern of the membrane can be easily derived from the considerations above outlined.…”

Fitting approach to liquid–liquid displacement porosimetry based on the log-normal pore size distribution

“…The algorithms which could be used for processing data 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 are very sensitive to experimental errors requiring some smoothing to get reasonable distributions. Some authors have performed spline smoothing to get better results from LLDP, [8,9], based on a polynomial fitting that somehow loses the physical meaning.…”