Langmuir Isotherm Calculator

Langmuir Isotherm Calculator

The Langmuir Isotherm Calculator computes the fraction of an adsorbent surface covered by an adsorbate using the Langmuir adsorption model. This model applies to monolayer adsorption on a homogeneous surface.

$$\theta = \frac{K_{eq} \cdot P}{1 + K_{eq} \cdot P}$$

where $\theta$ is the surface coverage fraction (0 to 1), $K_{eq}$ is the adsorption equilibrium constant, and $P$ is the partial pressure of the gas or molar concentration of the adsorbate in solution.

Surface coverage as a percentage is $\theta_{percent} = \theta \times 100$. At low pressure, coverage increases steeply with $P$. As the surface saturates, coverage approaches 1 (100%).

The Langmuir model assumes ideal gas behavior, a homogeneous surface, and monolayer adsorption only. It is widely used in physical chemistry, catalysis, and surface science.

Related tools: Equilibrium Constant Calculator, Concentration Calculator, and Diffusion Coefficient Calculator.