The correct form of the isotherm is: qe=BTln(KTCe)

The linear form of the isotherm is: qe=BT*ln(KT)+BT*ln(Ce)

or Y=BT*ln(KT)+BT*X

In an Excel data sheet put Ce data in column "A". In column "B" write  =ln(A1)

Apply this for all of the cells in column "A".

In column"C" put the "qe" data. 

Then plot column "B" vs. column "C"

Right click on the points of the plot and choose "Add Trendline", in the faced page on the bottom select "Display equation on the chart"

You'll see "y=...+...x" on the chart.

The Intercept of the line is BTln(KT), and the slop (coefficient of X) is the BT:

Slope: S=BT

Intercept: I=BT*ln(KT)=S*ln(KT)

or KT=e(I/S)

Thank you for your nice reply. but still, I am facing problem in calculating the values of parameters ( especially 'b'). So please help me in solving this problem. I have attached a copy of my data. and also I need help how to apply the nonlinear form of the model. 

Best regards

Please fined the attachment.

The coefficient for non-linear form is quite close to the linear form.

To fit the non-linear form you need to use a software such as Matlab, TableCurve and so on.

qe=48.796*Ln(553.292Ce)

BTW, note that the value of "b" depends on the unit of "R" you use!

thank you professor. it was really really helpful. 

thank you again

Salamolakum sir.

I need your help, once again. A number of authors have cited the following paper for Freundlich model, but I can't find it to download. [ H. Freundlich, Über die adsorption in lösungen (Adsorption in solution), Z. Phys. Chem. 57 (1906) 384–470]. if you found, please send to me on [email protected]. 

Salaam,

 Unfortunately I don't have access to the paper. By the way, as you may aware it is in German.

thank you all. I got it how to apply non-linear form of Temkin equation, in origin lab.

simply insert the this equation "qe=a*ln(b*Ce)" in origin lab and that will work. where a and b are the parameters, Ce is the independent variable, and qe is dependent one.

Hello Sir

Can you please tell me how to do non-linear regression analysis in Langmuir isotherm in Origin? How can I determine the initial values for the parameters i.e lower bound? The equation is qe= qmKCe/(1+KCe) where the parameters are qm, K.

Kindly provide me the steps. I have tried but cannot. Kindly reply Sir

With best regards

Hi dear Shilpi Das,

click on 'Analysis'-->Fitting--->Nonlinear Curve Fit--->Open Dialog.....

then click the down drop in 'Category' and select 'Hyperbola'. then in 'Function' down drop choose RectHyperbola' and click Fit button. exactly the same function is used for Nonlinear pseudo-second-order kinetic model. I have attached my articles, the first one gives nonlinear isotherms and kinetic study while the second one gives linear regression analysis, please cite them. thank you.

the equation in origin is y=abx/1+bx, where y=qe, a=qm, b=K, and x=Ce.

Hope I have helped.