Influencing Factors in Nitrogen Physisorption for Measuring Specific Surface Area and Pore Volume of Amorphous Silica
Amorphous silica, commonly known as precipitated silica or white carbon black, features a highly interconnected three-dimensional network formed through tetrahedral coordination of silicon atoms. The aggregation of its primary particles into larger agglomerates produces complex capillary channels, which create a highly porous internal architecture with a notably large specific surface area. These characteristics contribute to its exceptional adsorption capacity, reinforcement behavior, thickening properties, and its high chemical and thermal stability. Because of these advantageous traits, amorphous silica is widely used in industries such as rubber manufacturing, plastics, coatings, pharmaceuticals, food processing, catalysis, and personal care formulations.(1-6)
Nitrogen physisorption remains one of the most important analytical methods for determining the specific surface area, pore size distribution, and pore volume of amorphous silica. Among existing analytical approaches, BET surface area and mesoporous/pore structural analyses are often the most sensitive to pretreatment method, degassing temperature, measurement window selection, and sample storage history. This application note discusses how these parameters affect measured results and provides guidance for optimising measurement quality when using the AMI Micro 300 Series physisorption analyser.
