The best interpretation for the experimental data given by the

Langmuir isotherm equation and maximum adsorption capacity of the sorbent under the optimal conditions was 198.25 mgg-1.

The linear form

Langmuir isotherm equation can be represented by:

where [K.sub.L] is the equilibrium constant obtained from the

Langmuir isotherm equation, T is the absolute solution temperature (K), and R is the ideal gas constant (8.314 J/mol/K).

The linear form of the

Langmuir isotherm equation aids in the evaluation of the maximum adsorption capacity ([q.sub.max]) corresponding to monolayer coverage (or site saturation) and the Langmuir constant, [K.sub.L] of the adsorption process and is represented as:

The

Langmuir isotherm equation (Equation 2) is the most widely used two-parameter equation and has been successfully applied to many adsorption processes (Liu and Zhang, 2009; Cao et al, 2009; Chen et al, 2011).

The equilibrium data conform to the

Langmuir isotherm equation with the monolayer adsorption capacity of 112.5 mg/g and 91.07 mg/g for adsorbent treated with HCl and KOH, respectively.

Generally,

Langmuir isotherm equation can be expressed as (2) [5, 10], which is mainly based on the monolayer adsorption on the active reaction sites of the adsorbent:

Some consideration on the

Langmuir isotherm equation. Colloids and Surfaces A: Physicochemical and Engineering Aspects, v.

The sorption of Cu by the study soil was described by the

Langmuir isotherm equation (McBride 1994):

A possible explanation is that the xylidine adsorption equilibrium follows the Freundlich isotherm while the Rice method uses the linear isotherm and the Thomas method uses the

Langmuir isotherm equation. More precise numerical methods [e.g.

Thus, results were analyzed by plotting the data on

Langmuir isotherm equation.

The

Langmuir isotherm equation is represented by the following equation (Tsai et al.