When using methanol as a cosolvent to enhance the solubility of an analyte, does the cosolvent have an adverse effect on the textural and physico-chemical properties of activated carbon during adsorption testing?
Since the cosolvent is used to increase the solubility of the adsorbate, will this reduce the adsorption rate of the adsorbate to the adsorbent (activated carbon)?
I have personally never read anything about that in the literature, but I guess that indeed the solvent in which adsorption tests are carried out will have an impact on the results. Not on the textural properties themselves but on the kinetics and on the equilibrium values of uptake. In the liquid phase, adsorption is roughly accounted for half by porosity, half by surface chemistry. As the latter will be modified whether you are in water or in an organic solvent (point of zero charge and many kinds of adsorbent-adsorbate will be modified), then yes, I assume that the adsorption results will be different. It is difficult to foresee, however, whether they will be improved or not, as it strongly depends on the chemical nature of the adsorbent surface.
Alain
Thanks Alain Celzard. I did not forsee that until yesterday when i came across some number of articles that talked about the effect of methanol as a cosolvent on the adsorbent. First, the main thing that the articles mentioned was that the cosolvent will compete with the analyte for the active adsorption sites of the adsorbent and also that it is going to increase the complexity of the adsorption mechanism of the analyte. So i was wondering if this effect was considered by other articles that have worked on adsorption of a specific compound that requires the use of a cosolvent to enhance the solubility of the compound.