Glossary Of Terms

Featured Terms

Incorporation of the sorbed molecule into the host material...

An adsorbed molecule (see adsorption).

A solid or liquid capable of interacting with the adsorbate.

The accumulation of molecules at the surface of a solid or liquid...

A molecule capable of being adsorbed (see adsorption).

A pore size distribution determination method, typically applied to nitrogen desorption data measured at 77 K on mesoporous materials...

BET

Acronym for the Brunauer-Emmett-Teller equation, which is used to determine the specific surface area of solids...

In the gravimetric method, the change in the measured weight due to the displacement of the gas, following Archimedes’ Principle...

The process by which a liquid adsorbate phase is drawn into a pore...

See chemisorption.

The Gibbs Free Energy per mole of sorbate that expresses the work required to bring a sorbate molecule from a reference state (usually vacuum) to another state...

Adsorption due to chemical as opposed to physical forces, such as hydrogen chemisorption on the surface of a catalytically active surface...

The equilibrium state of a system containing more than one adsorptive.

The dead space correction in the volumetric method, which is the equivalent of the buoyancy effect correction in gravimetry...

Generic term for the reverse process of either absorption or adsorption induced by lowering the chemical potential...

The process by which sorbate molecules move in the host material, due to random molecular motion...

The DA equation is based on the DR equation and can be used to more effectively linearize the adsorption data and overcome the problems of characterising materials which give rise to curved DR plots...

DR Analysis is an approach to analyzing the gas adsorption isotherms of microporous materials based on Polanyi's potential theory of adsorption...

A technique for measurement of vapor sorption isotherms using a dynamic mode gravimetric sorption analyzer with vapors...

The relationship between the sorbate pressure, temperature and volume.

The time required for equilibrium to be obtained within a specified criterion, for example, that the process is 99% complete.

The state when the net rate of sorption is zero, i.e. the rates of sorption and desorption are equivalent...

The quantity determined in a gravimetric or volumetric adsorption experiment...

A relationship where the flux of diffusing sorbate is proportional to the sorbate concentration gradient...

Diffusion that obey’s Fick’s Law.

The tendency of the sorbate to change phase or to expand at constant temperature...

GAB

Acronym for the Guggenheim-Anderson-de Boer isotherm model...

The adsorption or absorption of a fluid in its gas phase...

Pertaining to the measurement of weight or weight change...

The skeletal density of a porous material determined with Helium (using pycnometry).

The HK method was developed for determining the pore size distribution of graphitic slit pores in microporous carbons using nitrogen adsorption measurements at 77 K...

A chemical compound formed between hydrogen and an element such as palladium or a compound such as LaNi5...

The process of forming a metal hydride.

Adsorption hysteresis is said to occur when adsorption and desorption values deviate from one another...

The standard enthalpy of adsorption at a fixed surface coverage...

Measurement of the amount sorbed as a function of sorbate pressure at constant temperature...

The property shown by molecular sieve materials in which the difference in the sorption kinetics of molecules of a different size or mass is used to select one species over another...

The isotherm, introduced by Langmuir in 1916, that describes the sorption of an adsorbate monolayer on a uniform surface in the absence of adsorbate-adsorbate interactions.

A pore of diameter between 2 nm and 50 nm...

A pore of diameter or dimension below 2 nm...

The sorption of water in the liquid or vapor phase.

A porous material that exhibits molecular sieving properties...

An adsorbed film that is one molecule thick (a Langmuir film)...

Adsorption on the monolayer.

Moisture Vapor Transmission Rate (see permeation).

Nanoporous materials have pores with a diameter or dimension below 100 nm...

PCI

A pressure-composition isotherm...

PCT

Acronym for pressure-composition-temperature, commonly used for hydrogen absorption isotherms determined for metal hydrides...

The steady state transfer rate of sorbate through a host material in defined conditions, which is a function of both solubility and diffusivity...

See physisorption.

Weak adsorption due predominantly to dispersive (Van der Waals) intermolecular forces...

Used to characterize (typically) microporous materials, such as activated carbons, that have an amorphous skeletal structure.

The volume of the pores, or voids, within a porous material...

Any solid containing pores and voids...

An adsorptive gas separation technique that uses changes in pressure to regenerate the adsorbent.

A technique for measuring volume...

P/Po, where P is the absolute pressure and Po is the saturation vapor pressure of the adsorptive at the experimental temperature...

The density of a solid calculated by excluding all open pores and internal void volume...

The magnitude of absorption expressed as a concentration under defined conditions or as a solubility constant...

A molecule capable of being absorbed (see absorption) or adsorbed (see adsorption).

A solid or liquid material capable of interacting with the sorbate.

Generic term for adsorption and absorption interactions proposed by J. W. McBain in 1909.

The surface area of a unit mass of material...

An adsorptive gas separation technique that uses changes in temperature to regenerate the adsorbent.

A thermal analysis technique that uses an applied temperature ramp to desorb adsorbed molecules from a solid, either into vacuum or a carrier gas.

The decomposition of a compound by heating.

The thermodynamic stability of a compound.

For metal hydrides, this is a plot of ln(P) against 1/T, where P is the plateau pressure of the hydride at a temperature, T...

The sorption of a fluid in its vapor phase...

Pertaining to the measurement of volume or volume change...

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