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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 ...
In capillary flow porometry, in opposition to mercury intrusion porosimetry, the wetting liquid enters spontaneously the pores of the sample ensuring a total wetting of the material, and therefore the contact angle of the wetting liquid with the sample is 0 and the previous formula can be simplified as: P= 4*γ/D.
The equation is named after Edward Wight Washburn; [1] also known as Lucas–Washburn equation, considering that Richard Lucas [2] wrote a similar paper three years earlier, or the Bell-Cameron-Lucas-Washburn equation, considering J.M. Bell and F.K. Cameron's discovery of the form of the equation in 1906. [3]
Mercury intrusion porosimetry (several non-mercury intrusion techniques have been developed due to toxicological concerns, and the fact that mercury tends to form amalgams with several metals and alloys). Gas expansion method. [6] A sample of known bulk volume is enclosed in a container of known volume.
BET model of multilayer adsorption, that is, a random distribution of sites covered by one, two, three, etc., adsorbate molecules. The concept of the theory is an extension of the Langmuir theory, which is a theory for monolayer molecular adsorption, to multilayer adsorption with the following hypotheses:
This may be written in the following form, known as the Ostwald–Freundlich equation: =, where is the actual vapour pressure, is the saturated vapour pressure when the surface is flat, is the liquid/vapor surface tension, is the molar volume of the liquid, is the universal gas constant, is the radius of the droplet, and is temperature.
Micro CT of porous medium: Pores of the porous medium shown as purple color and impermeable porous matrix shown as green-yellow color. Pore structure is a common term employed to characterize the porosity, pore size, pore size distribution, and pore morphology (such as pore shape, surface roughness, and tortuosity of pore channels) of a porous medium.
However, simple cooling of an all-liquid sample usually leads to a state of non-equilibrium super cooling and only eventual non-equilibrium freezing – to obtain a measurement of the equilibrium freezing event, it is necessary to first cool enough to freeze a sample with excess liquid outside the pores, then warm the sample until the liquid in ...