Hi dear,

I think that is a Isotherm Type II, since do not present hysteresis, which is typical for microporous or non porous. I know that some hydrogels are macroporous materials, so, I think that your material contain this kind of pores. Besides, it is a reversible isotherm, and from IUPAC classification It could be a macroporous material, as I stated previously.

Did you calculate the surface area?

Did you repeat your experiment?

Please, check it.

with kind regards,

Julián. 😄

Your sample barely adsorbs (see the y-axis). Since you did not mention, I will assume this is N2 adsorption at 77 K and base the following comments on this.

It does not seem to be microporous (no noticeable adsorption at low pressure), or mesoporous (no hysteresis) or even *clearly* non-porous (it would not fit a BET type isotherm, check this yourself!).

I think you are looking at the instrumental error of a sample with very low surface area.

Try running again your experiment with higher amount of sample. This isotherm is under the instrumental limits of detection. I wouldn't even say that there was hysteresis at all.