I mean, before using ACs for characterisation or other application (e.g. sorption tests), it is supposed to be:
Washed with DI water (or which other reagent)
Dried at 150 C
Is there anything else?
No pretreatment is required, If it is commercial carbon. If it is prepared in lab u can do wash it DI water. Characterization of ACs can be carriedout well by gas adsorption experiments from which we can know the surface area, pore volume and pore size distribution etc. simply, If you want to measure the adsorption of ACs, you can perform the iodine test or methylene blue test.
I don't think, any pretreatment is required, as the standard procedure for making activated carbon is treatment of wood carbon by water steam at high pressure and temperature.
Dear Antonio,
If you want to study gas or vapor adsorption on an activated carbon you must degas your sample to ensure that the complete porosity is available for gas adsorption.
If your activated carbon is going to be used for pollutant adsorption in aqueous phase no pretreatment is required but the determination of the humidity content could be helpful.
Dear Vanessa,
I always degas my samples before measuring gas adsorption.
However, I also apply my ACs for gaseous pollutant (CO2) adsorption so I was wandering if a pre-washing (DI water or any other reagent) would be helpful (especially in order to get rid of the residual ashes still anchored to pores).
Thanks,
Antonio
Dear Antonio,
If you want to do a theoretical study on CO2 adsorption, and i.e. study CO2 adsorption as a function of the pore size distribution I would say that you should get rid of ashes because they could have an effect on adsorption. Oxygen groups could also play a role at room temperatures and you should reduce them before starting.
If you are only testing different activated carbons to find a good commercial AC candidate for CO2 adsorption, degasification is enough.
In my RG profile, you will find some papers on gas adsorption in activated carbons.
Dear Vanessa,
Thanks for your interesting reply.
I'm using some wood-derived ACs and I'm measuring both CO2 adsorption isotherms (at 0 degC) and CO2 uptakes at higher temperatures (35-100 degC) by TGA. In the first case I degas the sample up to 100 or at most 200 C for few hours, whereas in the second one I degas the sample at 120 C for half an hour.
I'll have a look to your papers!
Washing with water and Degassing are the pretreatments for activated carbon
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