Aem Lect6

The BET method makes three main assumptions about gas adsorption: 1) it occurs on a flat, uniform surface; 2) there is no interaction between adsorbed gas molecules; and 3) multi-layer adsorption is possible. The BET equation relates the volume of gas adsorbed at a given pressure to the volume required for monolayer coverage and the saturation pressure of the gas. BET analysis uses an adsorption isotherm from multiple pressure points to calculate the specific surface area of a material. It is most accurate for surfaces that are flat and uniform with a consistent heat of adsorption for each layer.