Specific surface area

[4] For this reason, in addition to the most commonly used Brunauer–Emmett–Teller (N2-BET) adsorption method, several techniques have been developed to measure the specific surface area of particulate materials at ambient temperatures and at controllable scales, including methylene blue (MB) staining, ethylene glycol monoethyl ether (EGME) adsorption,[5] electrokinetic analysis of complex-ion adsorption[4] and a Protein Retention (PR) method.

The BET theory has inherent limitations but has the advantage to be simple and to yield adequate relative answers when the solids are chemically similar.

In relatively rare cases, more complicated models based on thermodynamic approaches, or even quantum chemistry, may be applied to improve the consistency of the results, but at the cost of much more complex calculations requiring advanced knowledge and a good understanding from the operator.

[8] This depends upon a relationship between the specific surface area and the resistance to gas-flow of a porous bed of powder.

The method is simple and quick, and yields a result that often correlates well with the chemical reactivity of a powder.