Freundlich equation

The Freundlich equation is an empirical adsorption isotherm relating the amount adsorbed to equilibrium concentration. Its power-law form often describes adsorption on heterogeneous surfaces over a limited concentration range.

Adsorption isotherm: A relation between the amount adsorbed and the equilibrium concentration or pressure at constant temperature. The Freundlich equation is one empirical form of this broader class of relations.
Langmuir adsorption model: An adsorption model describing monolayer coverage on a finite number of equivalent sites. Unlike the Freundlich equation, it predicts a finite saturation capacity.
Batch adsorption: An adsorption experiment in which an adsorbent and solution are mixed in a closed vessel until equilibrium. Equilibrium batch measurements provide data commonly fitted to the Freundlich equation.
Equilibrium constant: A quantity expressing the ratio of product and reactant activities at chemical equilibrium. It contrasts with the Freundlich constants, which are empirical fit parameters rather than universal equilibrium constants.
Parameter identifiability: The ability to determine unique model-parameter values from available observations. Correlated Freundlich parameters can be difficult to estimate reliably from narrow concentration ranges.
Freundlich adsorption isotherm: The Freundlich equation expressed as a specific adsorption-isotherm model, commonly written with an empirical exponent and capacity constant. This named form makes the equation’s concentration dependence explicit.
BET theory: A model of physical adsorption that extends monolayer adsorption to multiple molecular layers. BET theory addresses multilayer adsorption, while Freundlich is an empirical concentration relation.
Adsorption of dyes: The removal of dissolved dye molecules from liquids by their accumulation on a solid surface. Dye-removal studies often compare Freundlich fits across adsorbents.
Log–log plot: A graph that plots logarithms of both variables, turning power-law relations into straight lines. The Freundlich power law is commonly linearized this way to estimate its exponent and scale.
Model selection: The process of comparing candidate models to choose one suited to data and a scientific question. A good fit alone does not establish that Freundlich is preferable to other isotherms.

Linked from 3 pages