This package provides a measurement of the nitrogen-accessible specific surface area of the sample using the five-point Brunauer–Emmett–Teller (BET) method. Nitrogen adsorption measurements are collected at five relative-pressure points within the selected BET region, and the resulting data are used to calculate the specific surface area in m²/g. The nitrogen adsorption isotherm is also provided.

 

Specific surface area is an important characteristic of biochar because it provides an indication of the surface available for interactions such as adsorption, nutrient retention and contaminant binding. However, the BET surface area does not by itself describe the sizes or volumes of the pores within the biochar.

 

This package is most suitable for basic screening, routine quality control or comparison of similar biochars where only an indicative BET surface-area result is required. Because biochars can contain complex combinations of micropores and mesopores, a larger number of isotherm datapoints generally provides a more complete and reliable description of their pore structure. For detailed biochar characterisation, we recommend a higher-resolution package such as P364, which uses 20 isotherm datapoints and provides additional information on pore volume and pore-size distribution.

Constituents Determined

For every constituent determined via wet-chemical analysis each sample is analysed in duplicate and we provide the compositional data for each replicate along with the average value and the standard deviation between the duplicates. Our analytical protocols typically provide results with a high level of precision, as detailed here.

Examples of the data reports generated can be viewed on the Celignis Database. Please log on to the guest account using email "test@celignis.com" and password "celignis".

Click here to place an order for determining Specific Surface Area (5-Point BET).

Sample Weight Requirements

Under nornal conditions there is a minimum requirement of 1g of sample for this analysis package with a recommended weight of 5+g of sample.

However, it may be possible for us to undertake the anaysis with lower quantities than the minimum specified above. Please email us at info@celignis.com to find out.

Equipment Used for Specific Surface Area (5-Point BET)