p
Packing density of membranes: Surface area of membrane per volume unit of a membrane apparatus.
Penetrant (permeant): Entity from a phase in contact with one of the membrane surfaces that passes through the membrane.
Permeability coefficient: P, [kmol m m-2s-1 kPa-1]: Parameter defined as a transport flux, Ji, per unit transmembrane driving force per unit membrane thickness, viz., Pi = Ji / [transmembrane driving force of component i/l] {Note: other commonly used units for Pi include [m3 m m2 s-1 kPa-1], [m3 (measured at standard temperature and pressure m m-2 s-‑1 kPa-1 ] or [kg m m-2 s-1 kPa ]}.
Permeance (pressure normalized flux): [kmol m-2 s-1 kPa-1]: Transport flux per unit transmembrane driving force, viz., Pi/l (§28) {Note: other commonly used units include [m3 m-2 s-1 kPa ], [kg m-2 s-1 kPa-1 ], or [m3 (measured at standard temperature and pressure) m-2 s-1 kPa-1]}.
Permeate post-treatment: One or more final conditioning steps to improve permeate quality, e.g., contacting with anion exchange resins to remove trace ions in the permeate of a reverse osmosis product stream.
Permeate: Stream containing penetrants that leaves a membrane module.
Perstraction: Separation process in which membrane permeation and extraction phenomena occur by contacting the downstream with an extracting solvent.
Pertraction: Separation process in which membrane permeation and extraction phenomena occur by contacting the downstream with an extracting solvent.
Pervaporation: Membrane-based process in which the feed and retentate streams are both liquid phases while permeant emerges at the downstream face of the membrane as a vapor.
Phase inversion membrane: Membrane prepared using the phase inversion (decomposition) method.
Phase inversion: A stage of membrane formation process; at that stage membrane forming polymer is transferred under controlled regime from liquid phase (solution) into solid phase (membrane).
Polymeric membrane: Membrane made of synthetic or natural polymers.
Porous membrane: Membrane that includes permeable channels.
Potable water: Term used to indicate water having a total dissolved solids content of less than 500 ppm with a sufficiently low level of biological agents, suspended solids, organic odour- and colour-generating components to be safe and palatable for drinking.
Pressurized gas separation: Realization of membrane gas separation when the driving force is produced by pressurization of the mixture to be separated.
