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BET analysis: determination of the surface area of solid materials by gas adsorption

At Delft Solids Solutions, they specialise in the characterisation and testing of bulk solids and powders, such as powder characterisation. Handling powders and granular materials is of great importance to industry, as these materials are used in 80% of industry. The physical properties of powders and granular materials, such as cohesion, density, compressibility, particle size distribution, particle shape and moisture, affect the flow and fluidity of the bulk. In addition, solid particles wear out during production, handling and transport, which can lead to fragmentation and abrasion.

At Delft Solids Solutions, they offer various research methods to characterise and test the behaviour of bulk powders, such as powder characterisation. This includes measuring powder flow, measuring powder compact strength, measuring powder stickiness, analysing dust formation and testing wear and segregation of particles.

This expertise is used for various industries, including pharmaceutical, chemical, petrochemical, automotive, food and building materials industries. Delft Solids Solutions collaborates with national and international laboratories and institutes to offer complementary facilities and expertise.

More information about Delft Solids Solutions’ services and expertise, such as powder characterisation, can be found on their website.

What is BET analysis?

BET analysis is a technique used to determine the surface area of a solid material by physical gas adsorption. In this process, an inert gas, usually nitrogen, is absorbed on the surface of the material. This occurs both on the external surface and, in the case of porous materials, also on the internal surface caused by pores. This adsorption of nitrogen leads to a so-called adsorption isotherm, which can be measured across porous and non-porous materials. The BET surface can be determined based on a type II isotherm for non-porous materials and a type I or type IV isotherm for porous materials. For specific materials such as zeolites or activated carbons, argon or carbon dioxide adsorption is often used instead of nitrogen adsorption to accurately examine the small micropores. A BET analysis can also be performed on krypton gas adsorption for samples with a low BET surface area.