porozimetri

Porozimetry refers to the measurement of pore size distribution and pore volume within a material. This technique is crucial in understanding the properties and behavior of porous substances, which are found in a wide variety of applications, from catalysis and filtration to drug delivery and geological formations. Different methods exist for porozimetry, each suited to specific pore size ranges and material types.

Mercury intrusion porosimetry is a common technique used to analyze macropores and mesopores, typically ranging from a few nanometers to several hundred micrometers. It operates by forcing mercury into a sample under increasing pressure. The applied pressure is inversely proportional to the pore diameter, allowing for the calculation of pore size distribution. This method is effective for rigid materials that can withstand the applied pressures but can be destructive to some samples.

Gas adsorption porosimetry, particularly nitrogen adsorption at cryogenic temperatures, is widely used to characterize micropores and mesopores, generally from sub-nanometer to about 50 nanometers. This method relies on the principles of gas adsorption and desorption onto the surface of the porous material. By analyzing the adsorption isotherm, which plots the amount of gas adsorbed against the relative pressure, information about pore volume, surface area, and pore size distribution can be obtained. This technique is generally non-destructive and provides detailed information about the finer pore structures.

Other methods, such as small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS), can also provide information about pore structure, particularly for nano-scale porosity. The choice of porozimetry technique depends on the specific material being studied, the pore size range of interest, and the desired information.