Dear All,

I am looking for a best model for fitting the adsorption isotherm of Rhodamine 6G dye on Silica (MCM-41). The corresponding isotherm is attached herewith for your information.  

I have tried the fitting of isotherm using Langmuir-Freundlich model having the equation as Q=Qsat*K*C^n/[1+K*c^n]. But it is not fitting nicely, rather it is showing the behaviour of Type-II isotherm. 

Please let me know the possible fitting model and equation for the same. 

Thanks for your great help..

Sincerely,

Pradip