I have been trying to apply the non-linear Flory Huggins model (see below) to explain the experimental adsorption data but I was not successful.
theta/Co = KFH (1 − theta)^nFH
where, theta= 1-(Ce/Co)
KFH and nFH are equilibrium constants
All the literature reported converted that above equation into a linear form and then, obtained the equilibrium constants from the slope and intercept. However, it is well known that converting a non-linear equation to linear form would induce errors. For the same reason, I tried to apply the non-linear equation but i am getting confused of how to exactly proceed. Any help would be appreciated.
Thank you!
Regards,
Sai.
Why don't you choose common isotherms such as Langmuir or freundlich isotherms?
Dr. Mohammad Reza Toosi,
I was trying to model Flory-Huggins in order to calculate the equilibrium constant KFH which can be used to determine gibbs free energy through the following equation:
delta G0 = RT ln (KFH)
Ok.
However, using other isotherms named above you can determine delta G by plotting adsorption capacity vs. Temperature.
Check here, may be can help you to use or not that model according with your system.
https://www.sciencedirect.com/topics/engineering/flory-huggins-equation
Other solution is with Origin, search here in RG to know how to do, but Mohammad Reza Toosi show the solution.
Sai Teja Neeli , I reply very late. You cannot transform a nonlinear equation to a linear equation and vice versa. What you call the linear form of the H-F isotherm is actually the implicit form of the isotherm with respect to the dependent variable. Obviously, transforming an equation to its implicit form changes the error distribution and the new variables have an unknown statistical distribution. So it is better to use the explicit form of H-F isotherm you call nonlinear and nonlinear regression.
This video shows how to fit Flory huggins isotherm model in origin: https://youtu.be/nADJPLCpIh8