I would like to get the pore size distribution (0.5nm~1.5nm) from the CO2 isotherm using a DFT model (CO2 @ 273 on Carbon, Slit Pores) and have some questions about the procedure.
1 - Which p/p0 range should I use and how many points should I get?
2 - Should I ask the ASAP to measure p0 or should I enter a fixed value myself? p0 = 26142 mmHg is the correct value?
3- After performing the procedure, do I need to purge the ASAP lines to perform an n2 isotherm?
Thank you for your attention.
3) There are 6 (?) different gaslines on the 2020, connect to one of them and specify which one is CO2 in the software.
2) Where do you get that value for P0? Should be around normal pressure or 760 mm Hg.
And first of all, check if Your 2020 can do µ-pore measurements. It the standard configuration it cannot go below 1.5 nm pores. You should have an extra turbo-pump and an extra pressure transducer.
2) p0 of CO2 at 273K is indeed 26142 torr, so the ASAP will not be able to measure it. You can enter a fixed value of 26412, but if you do, don't ask for p/p0 values above ~0.03. A very convenient way to do this would be to enter a value of 760 torr (1 standard atmosphere and select point in the usual way starting as low as you like up to 0.995). THEN, once the isotherm has been measured, change p0 to 26142 in the software before calculating pore size. I'm assuming the s/w has a p0 "overwrite" function.
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