Search results
Results from the WOW.Com Content Network
This equation describes the adsorption of one adsorbate to two or more distinct types of adsorption sites. Each binding site can be described with its own Langmuir expression, as long as the adsorption at each binding site type is independent from the rest.
The Langmuir Isotherm describes the adsorption of a substance onto a solid surface. It defines the relationship between the concentration of an adsorbate (the substance being adsorbed) in solution and its coverage on the surface of an adsorbent (the solid material).
Despite its simplicity, the Langmuir adsorption model captures the key physics of molecular interactions at interfaces and laid the foundation for further progress in understanding interfacial phenomena, developing new adsorbent materials, and designing engineering processes.
The Langmuir isotherm equation is represented as: (1) Where qe is the adsorption capacity adsorbed at equilibrium, qmax is the maximum adsorption capacity (anions mg/g of resin), kL is the Langmuir adsorption constant (L/mg), and Ce is the equilibrium concentration of the adsorbate (mg/l).
The nonlinear equation of the Langmuir isotherm model can be expressed as (Langmuir, 1918): (5.18) q e = Q 0 K L C e ( 1 + K L C e ) where C e and q e are the equilibrium liquid-phase concentrations of adsorbate (mg/L) and the amount of adsorbate adsorbed onto the adsorbent (mg/g), respectively.
The adsorption process between gas phase molecules, A, vacant surface sites, S, and occupied surface sites, SA, can be represented by the equation, assuming that there are a fixed number of surface sites present on the surface. An equilibrium constant, K, can be written: q = Fraction of surface sites occupied (0 <q< 1) Note that
The Langmuir adsorption isotherms predict adsorption at low adsorption densities and a maximum surface coverage at higher solute metal concentrations. Langmuir adsorption is applicable for monolayer adsorption onto a homogeneous surface when no interaction occurs between adsorbed species.
between the surface adsorption, the lowering of the surface tension and the concentration of the solution. The equation that he deduced can readily be put in the form dF (1) where p is the partial pressure of the vapor of the adsorbed substance in equi-librium with the surface of the liquid, or it may be the partial osmotic pres-
The Langmuir adsorption model is most common for quantifying the amount of adsorbate adsorbed onto a material (called an adsorbent) as a function of partial pressure at a given temperature. It includes the following assumptions:
The Langmuir adsorption isotherm can be written:θ=bp/ (1+bp), where θ is the fraction of the surface covered by the adsorbate, p is the pressure of the gas, and b is a constant called the adsorption coefficient, which is the equilibrium constant for the process of adsorption.