Langmuir Adsorption Isotherm (θ = Kp/(1+Kp); x/m = aKp/(1+Kp))

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θ = Kp/(1+Kp); x/m = aKp/(1+Kp)

What each symbol means

SymbolWhat it stands for
KLangmuir equilibrium constant (related to adsorption energy)
aCapacity factor (often treated as monolayer capacity in mass form)
pEquilibrium pressure of adsorbate
θFraction of surface covered by adsorbate (0 to 1)
x/mMass adsorbed per unit mass of adsorbent at pressure p

When to use this

Assumes monolayer adsorption on a uniform surface; no interaction between adsorbed molecules; dynamic equilibrium between adsorption and desorption. Best at moderate pressures before multilayer dominates.