The sorption capacity of a material is related to a material’s surface chemistry, surface area, and, if applicable, its pore size distribution. The sorption properties of a material can inform on all these properties, as well as develop a key understanding of a material’s performance, lifespan, and activity. The sorption capacity of a material is important across a number of industries, and the applications below will describe in more detail some of the uses of Dynamic Vapor Sorption to measure sorption capacity.
The moisture sorption capacity for building materials such as cement, wood, insulation material, and fibers has significant implications on a building’s lifespan, as well as having a big effect on indoor air quality and air-conditioning loads.
Dynamic Vapor Sorption can be used to measure the sorption capacity for these materials, including water, and other vapors of interest such as VOC’s and pesticides. The following application note gives an overview of the use of DVS to measure the uptake of water in cement, wood, and insulation materials.
DVS Application Note 104: Vapour Sorption Properties of Building Materials using Gravimetric Sorption Instrumentation – an overview | Request a copy
Crystalline materials have a lower sorption capacity than amorphous materials, as excess solvent is lost during crystallization. The sorption capacity of an amorphous powder can therefore be used to determine the amorphous content, with respect to the known reference materials.
It is also important to understand the deliquescence of any materials that are soluble in water, as this dictates the stability of a formulation and has a great impact on the storage and processing of the pharmaceutical. Sorption capacity may also reflect a drug’s hydrate formation behavior, which can have great implications on the stability of the drug and its pharmacological response in the body.
DVS Application Note 46: Combining Raman Spectroscopy with Gravimetric Vapour Sorption Analysis for Pharmaceutical materials | Request a copy
In the hair care sector, the sorption capacity of hair has a direct correlation to the damage level in the fiber. The water sorption capacity of hair at high relative humidity has therefore become a critical component in the industry as a measure of damage.
Dynamic Vapor Sorption techniques are ideal for measuring water sorption isotherms for hair, allowing full analysis of both the sorption capacity and hysteresis of the isotherms. The following application note demonstrates the use of DVS in tandem with iGC methods to determine differences in sorption capacity and surface heterogeneity between damaged and undamaged hair samples.
DVS/iGC SEA Case Study 616: Determination of Surface Properties of Human Hair by Inverse Gas Chromatography and Dynamic Vapour Sorption | Request a copy
Volatile Organic Compounds (VOCs) are generated from a wide range of plastics, upholstery, and carpeting leading to what is known as ‘sick building syndrome’. VOC capturing compounds such as zeolites must have high sorption capacities for VOCs to effectively remove this indoor air pollution.
Dynamic Vapor Sorption can directly measure the sorption of VOCs such as methanol in zeolites, in the presence of water under real-world conditions. DVS can be used to screen for better sorbents to address this problem which can lead to pulmonary diseases, difficulties in concentration, and other symptoms of acute discomfort.
DVS Application Note 65: Impact of Relative Humidity on the Adsorption of Volatile Organic Compounds by Porous Materials – Two Component Sorption Study | Request a copy
BET Surface Area and Pore Distribution
The sorption capacity of a material is dependent on the surface area and pore size distribution. Both factors are important for understanding how a material behaves and how to formulate better products.
Both Dynamic Vapor Sorption and Inverse Gas Chromatography can be used to determine the BET surface area of a material, with the isotherm shape also determining porosity. If the material is porous, the distribution of pore sizes can be calculated from the isotherm using the Kelvin equation.
Application Note 18: Measuring BET Surface Areas using Organic Probe Molecules | Request a copy
Application Note 37: Hysteresis Effects in Vapour Sorption | Request a copy
Determining Sorption Capacity with DVS & iGC
Sorption Capacity can be determined accurately and in great detail with our DVS & iGC instruments. To find out more, see which of our products can provide this capability in your lab.