How can I draw the theoretical graph and draw constants of Langmuir adsorption isotherm to compare it with the experimental one?
by using the Excel solver for instant and using a least squared fitting procedure.
Least square fitting of the experimental adsorption data would provide you both the best plot through experimental points as well as the estimates of the constants in the isotherm. Many general purpose softwares may be used for this purpose like Microsoft Excel, PTC Mathcad or Matlab. Alternatively a hand held calculator may be used to fit the data onto the linearized form of the Langmuir adsorption isotherm. This would also provide the estimates of the constants. Next graph may be drawn manually.
Mr. Syed, can you please give a graphic example as an attachment? That would help a lot! Thanks, Salehin.
Dear Salehin, here is an example of data fitting to Langmuir adsorption isotherm. Hope this would be beneficial. The problem was solved in Mathcad.
This is a typical inverse problem for a hyperbolic function which is the Langmuir isotherm. The mean relative error can be used as the objective function and the Levenberg-Marquardt procedure as the minimization method. It is built into, for example, Statistica or MathLab. The starting point can be obtained from the graphical method, where Ce/qe is plotted against Ce or 1/qe is plotted against 1/Ce.