The Langmuir Isotherm Calculator is a scientific tool used to determine how molecules adsorb onto a solid surface. It helps calculate the relationship between adsorbate concentration and surface coverage at equilibrium.
This calculator is widely used in chemistry, environmental science, materials engineering, and surface science research to analyze adsorption behavior in liquids and gases. Instead of doing long manual calculations, users can instantly get accurate results for monolayer adsorption capacity and adsorption intensity.
Simply put, this tool makes complex surface chemistry calculations fast, simple, and reliable.
The Langmuir Isotherm Model describes how molecules stick (adsorb) onto a solid surface in a single molecular layer. It assumes:
Adsorption happens at specific homogeneous sites on the surface
Each site holds only one molecule
No interaction occurs between adsorbed molecules
Adsorption reaches dynamic equilibrium
It is one of the most important adsorption models in physical chemistry and is used to study pollution control, catalysis, drug delivery, and nanomaterials.
Below are the core Langmuir Isotherm equations used in this calculator:
Langmuir Isotherm Equation:
q = (qmax × KL × C) / (1 + KL × C)
Linear Form of Langmuir Equation:
C/q = (1 / (KL × qmax)) + (C / qmax)
Where:
q = Amount of adsorbate adsorbed per unit mass of adsorbent
qmax = Maximum monolayer adsorption capacity
KL = Langmuir adsorption constant (binding energy indicator)
C = Equilibrium concentration of adsorbate
These formulas help determine how strongly molecules bind to a surface and the maximum adsorption limit.
Let's say we have:
qmax = 50 mg/g
KL = 0.2 L/mg
C = 10 mg/L
Step 1: Multiply KL and C
0.2 × 10 = 2
Step 2: Add 1
1 + 2 = 3
Step 3: Multiply qmax × KL × C
50 × 0.2 × 10 = 100
Step 4: Divide
q = 100 / 3 = 33.33 mg/g
So, the adsorption capacity at equilibrium concentration 10 mg/L is 33.33 mg/g.