BET surface area analysis is a technique used to determine the specific surface area of powders, solids and granules, the values are expressed in meter square per gram.
Clean solid surfaces adsorb surrounding gas molecules and Brunauer, Emmett and Teller theory (BET) provides a mathematical model for the process of gas adsorption. This physical adsorption of a gas over the entire exposed surface of a material and the filling of pores is called physisorption and is used to measure total surface area and pore size analysis of nanopores, micropores and mesopores.
The BET surface area measurement is crucial in understanding the behaviour of a material, as material reacts with its surroundings via its surface, a higher surface area material is more likely to react faster, dissolve faster and adsorb more gas than a similar material with a lower surface area.
Typical analysis would include:
- Specific surface area BET surface area analysis using Nitrogen, or Krypton for low surface area materials
- Pore size analysis. Mesopore analysis using traditional Kelvin equation models such as BJH, or advanced DFT based models.
- Micropore analysis Accurate measurement of micropores requires high vacuum, accurate low pressure transducers and advanced pore modelling calculations such as Quantachrome’s range of DFT micropore models.
- Pore size distribution by: pore diameter, pore volume and pore surface area.
- Percentage of porosity