I have implement adsorption test of oil/water solution using modified zeolite as adsorbent, the BET analysis for the used adsorbent indicate there is 30% increase in surface area.
kindly note that my samples are homogenized and the test repeated 3 times with the same results.
Dear Sebastian,
Many thanks for your answer, I degassed my sample at 105 C , particle size distribution dose not changed.
Dear Noor,
It is well known that oil is not soluble in water. So, firstly, I wonder how did you have implement adsorption test of oil/water solution using modified zeolite as adsorbent?
In this conditions, oil molecules will be surrounded by water molecules. Any two oil molecule cannot easily access each other because they are covered by sheat of water molecules (Reference https://www.physicsforums.com/threads/how-solubility-of-oil-in-water-is-effected-by-temperature.248540/)
On the other hand, according to literature, it should be possible to use the difference between the experimental and calculated surface areas as a measure of various properties of a given sample. May be this give you an idea for solve your problem.
I'm not sure but, if the zeolite you use as sorbent is in its sodium form and if these sodium cations could be partially exchanged by protons during your process, this exchange of sodium by H+, a less bulky cation, it could result in a increase of surface area.
To better understand what is occurring, you could measure the complete isotherm (including the very low pressure part) in order to determine if the change of surface area is due to a change in the external surface area (that would be indicative with a decrease in the particle size) or in the microporosity.
By the way, you indicate that you degass your samples at 105°C, which is, a bit too low for a zeolite, one usually uses 250-300°C.
Hi Noor,
Please, which instrument you have used for BET and with which gas ? How you did the degassing for your samples before and after used? Regarding your zeolites, has it been prepared by yourself or by suppliers?
Actually, it is possible to increase the BET after degassing if we consider the solvent-exchange activation was happened between the adsorbent molecules and the impurities inside the pores.
Two things here:
Good luck!
Hi Noor
According to your words, may be some new active sites are formed during degassing at 105oC (I think this temperature is not not correct upon doing outgassing).
Which temperature you have used to do outgassing for zeolite alone?
Regards,
Fathy
@Olcayto Keskinkan ·@Venkata Pramod @Juliette Blanchard @Venkata Pramod @Sebastian Hippmann @ Hussein Abid @Fernando Vallejos-Burgos Nady Fathy @
Hai Tran Many thanks for all this information and logical explanation , it is really highly appreciated. I will take it all onto my consideration, and after reading all the sent attachment I will write an answer to discuss.
many thanks again.
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