In my result, when I applied the Langmuir and Freundlich isotherm model. I got an R2 value is around 0.99 for the linear curve in both models however, on the non-linear fit curve Langmuir model does not show the same value it is negative. So is it possible? if yes, then why it's so different . or am I making a calculation error please help.
Could you please explain what you mean by negative?
What nonlinear equations you used?
Please look at my papers for help
https://scholar.google.com.eg/citations?user=YMWwJ_QAAAAJ&hl=en
Ismail
Ismail Badran Thank you for your reply. When I plotted a linear graph for Langmuir, I got an R2 value of 0.98, while with the same data, I plotted a non-leaner graph, and I got an R2 value of -13.56. Is it possible ? However, for Freundlich, I got a similar R2 value for both linear and non-linear curves which was identical to 0.99. I will definitely go through your paper.
The maximum value of R2 should be 1. I don't know how did you get -13!!
I advice you to use Origin for your fittings and use the correct models
@i have already used origin and also used same model in previous paper. But i don't know why its coming anyway ill check again. Thanks for the quick reply means a lot 🙏🏻🙏🏻🙏🏻
You might double ckeck your fitting using pyGAPS. It is an open source software by Paul Iacomi.
https://github.com/pauliacomi/pyGAPS-gui
If you have more detailed questions, feel free to send me a DM.
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