What is the porosity? How to measure porosity using true density meter and specific surface area meter？

Porosity generally refers to the ratio of the total pore volume of porous materials to the apparent volume (which is the total pore volume+skeleton volume). Density, relative to porosity, refers to the degree to which the material is filled with solids inside. The porosity or density of a material directly reflects the degree of material compaction.

Porosity is divided into effective porosity and absolute porosity (total porosity), which are related to the shape, structure, and arrangement of solid particles in porous media. Porosity has a significant impact on catalyst preparation, catalyst activity, stability, and selectivity.

Our company provides two methods for determining porosity, suitable for different scenarios.

1. True density combined with apparent density.

Combining true density with apparent density, suitable for large volume particles (>500 μ m) Or block like material (unlimited shape). The true density (also known as skeleton density) and skeleton volume can be measured using the BUD-TD20 true density analyzer of BUILDER. At the same time, the apparent density and apparent volume of the material can be obtained using the wrapping method, and the porosity can be calculated using the skeleton volume and apparent volume. Alternatively, the porosity containing void volume can be calculated using the compacted density.

For regular block materials, the apparent volume can be obtained by accurately measuring the dimensions of each side, using mathematical formulas to calculate, and combined with the BUD-TD20 true density analyzer to determine the skeleton volume and calculate the porosity.

2. Total pore volume measured by physical adsorption combined with true density.

By combining physical adsorption with true density, the SSA7000 physical adsorption instrument can obtain a total pore volume in the range of 0.35 to 500nm. Combined with the BUD-TD20 true density analyzer to measure the skeleton volume, the porosity of pores in the range of<500nm can be obtained.