Principe : The specific surface area represents the total surface area per unit mass of the product accessible to the atoms and molecules. it is, therefore, to consider the entire surface of each particle, the porosity open understood.
the principle of the measurement is based on the phenomena of adsorption and desorption of an inert gas (for example nitrogen) on the porous particles. the different processes using the physical adsorption of gases at low temperature are based on the work of brunauer, emmett and teller, known more generally as the initial bet, and dating back to 1938.
the isotherm obtained is used to calculate the different parameters characterizing the surface of a powder. indeed, from the volume of gas forming a layer of monomolecular to the surface of the particles, the device calculates the specific surface of a sample. the condensation capillary gives access to the determination of the pore volume.