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In ultrafiltration, the molecular weight cut-off or MWCO of a membrane refers to the lowest molecular weight of the solute (in daltons) for which 90% of the solute is retained by (prevented from passing through) the membrane, [1] or the molecular weight of the molecule (e.g. globular protein) that is 90% retained by the membrane.
Different dialysis tubing or flat membranes are produced and characterized as differing molecular-weight cutoffs (MWCO) ranging from 1–1,000,000 kDa. The MWCO determination is the result of the number and average size of the pores created during the production of the dialysis membrane.
Dialysis is the process used to change the matrix of molecules in a sample by differentiating molecules by the classification of size. [6] [7] It relies on diffusion, which is the random, thermal movement of molecules in solution (Brownian motion) that leads to the net movement of molecules from an area of higher concentration to a lower concentration until equilibrium is reached.
The pore sizes of technical membranes are specified differently depending on the manufacturer. One common distinction is by nominal pore size. It describes the maximum pore size distribution [10] and gives only vague information about the retention capacity of a membrane. The exclusion limit or "cut-off" of the membrane is usually specified in ...
It is widely used to measure minimum, maximum (or first bubble point) and mean flow pore sizes, and pore size distribution in membranes [1] nonwovens, paper, filtration and ultrafiltration media, hollow fibers, [2] ceramics, etc. In capillary flow porometry an inert gas is used to displace a liquid, which is in the pores. The pressure required ...
Porosimetry is an analytical technique used to determine various quantifiable aspects of a material's porous structure, such as pore diameter, total pore volume, surface area, and bulk and absolute densities. The technique involves the intrusion of a non-wetting liquid (often mercury) at high pressure into a material through the use of a ...
Schematic of semipermeable membrane during hemodialysis, where blood is red, dialysing fluid is blue, and the membrane is yellow. Kidney dialysis (from Greek διάλυσις, dialysis, 'dissolution'; from διά, dia, 'through', and λύσις, lysis, 'loosening or splitting') is the process of removing excess water, solutes, and toxins from the blood in people whose kidneys can no longer ...
Semipermeable membrane is a type of synthetic or biologic, polymeric membrane that allows certain molecules or ions to pass through it by osmosis. The rate of passage depends on the pressure , concentration , and temperature of the molecules or solutes on either side, as well as the permeability of the membrane to each solute.