The size of the particles are around 146 nm, specific surface area is 0.05 m2/g and 1.7 g of sample was used. Adsorption was measured at 77 K using nitrogen gas. I cannot figure out the problem and would be grateful to receive your suggestions.
Dear Sir,
Thank you for the answer. The operating conditions are as follows.
Sample Mass: 1.7646 g
Cold Free Space: 47.8876 cm³
Low Pressure Dose: None
Analysis Adsorptive: N2
Analysis Bath Temp.: -197.075 °C
Thermal Correction: No
Warm Free Space: 15.6163 cm³ Measured
Equilibration Interval: 45 s
Automatic Degas: Yes
Dear Sir,
The sample was degassed at 250oC under vaccum. However, I cannot confirm the time lapse since the analysis was contracted out to a South-African lab due to unavailability of resources in Mauritius.
Dear Dr Mauthoor, by the parameters of you publish, I deduced that you have one Micromeritics ASAP 2010 o 2020, and you used a tube of 1/2 inch with filler rod. You don’t informed about the volume adsorbed, but for a surface area of 0.05 m2/g and mass of 1.7 g, you isotherm probably adsorb 0.02 cm3 STP approximately. I think that this isotherm is impossible to measure with precision in your equipment. To test your equipment I recommend measuring an empty tube, and compare the two isotherms, with sample and without sample. To measurements very low areas you need use Krypton, (very expensive), or more sample and reduce as soon as possible the free volume of holder. May be you have access to another equipment more adequate to determine very, very low areas. Normally are less expensive.
I attach a graphic whit the precision that you can obtain with different equipment. Test your results whit this information and think about of sample to you need uses.
Dear Dr. Parra. Thank you for this constructive explanation. With such a low surface area, the instrument could not perform well.
I suggest for you to use a small amount of sample from 50 mg to 200 mg. I have already the same problem.
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