Gas permeable membrane or similar way to achieve

[Numus]

I am doing research on the partitioning coefficent of Radon in the gas and liquid phase with respect to salinity. I ran into a snag when I failed to realize Instant Ocean (approximate ocean salt material) froths when gas is bubbled. I have a small Dryrite tube and can't modify the rest of the tubing (system has been calibrated for the exact gas volume) and the problem is once any liquid gets into the dryrite tube (meant for humidity only) it turns into a rock. So basically I need to figure out something I can put before the dryrite that is only gas permeable but wont absorb radon. Any suggestions?

Edited November 10, 2010 by Numus

[CaptainPanic]

Just summarizing (it took me a while to understand your problem):

- You have some kind of a liquid container with something that approaches ocean water. You use "instant ocean" (which, for those not in North-America, is a brand of salt - to create salty water for an aquarium).

- You then bubble your gas through it (gas that contains Radon)?

- Normally, the gas then goes to the Drierite tube (which is a gas cleaning tube). But your bubbles create such a froth that you make the Drierite tube wet, which ruins the experiment.

 

You look for something that is only gas permeable. Just some cloth? Or perhaps filter papers? Make sure that your gas pump can handle it.

Forget about molecular sieves - those are selective for gases.

 

Alternatively, you mention that your research is to find the partition coefficient with respect to salinity. Then why do you care about all that muck that creates the sea foam (which is lipids, proteins, lignins and other organic material). Admittedly, those can also carry a charge (especially the proteins), but I am not sure they count as salts.

 

Why not use normal salt first? Just regular table salt will not create froths.

Then you can measure some individual organic materials (some proteins or amino acids at varying pH), and see if they have a big influence. If all the organic material has almost no influence, you can leave it out and work with a non-foaming salt solution.

 

If it does influence the Radon adsorption (or the equilibrium) then you're onto something too - I assume that's interesting too.

 

In short: I would split up the experiment into several more simple ones.

[Numus]

Just summarizing (it took me a while to understand your problem):

- You have some kind of a liquid container with something that approaches ocean water. You use "instant ocean" (which, for those not in North-America, is a brand of salt - to create salty water for an aquarium).

- You then bubble your gas through it (gas that contains Radon)?

- Normally, the gas then goes to the Drierite tube (which is a gas cleaning tube). But your bubbles create such a froth that you make the Drierite tube wet, which ruins the experiment.

 

You look for something that is only gas permeable. Just some cloth? Or perhaps filter papers? Make sure that your gas pump can handle it.

Forget about molecular sieves - those are selective for gases.

 

Alternatively, you mention that your research is to find the partition coefficient with respect to salinity. Then why do you care about all that muck that creates the sea foam (which is lipids, proteins, lignins and other organic material). Admittedly, those can also carry a charge (especially the proteins), but I am not sure they count as salts.

 

Why not use normal salt first? Just regular table salt will not create froths.

Then you can measure some individual organic materials (some proteins or amino acids at varying pH), and see if they have a big influence. If all the organic material has almost no influence, you can leave it out and work with a non-foaming salt solution.

 

If it does influence the Radon adsorption (or the equilibrium) then you're onto something too - I assume that's interesting too.

 

In short: I would split up the experiment into several more simple ones.

Right on all the assumptions for the analytical setup... I am a chemical Oceanography graduate student attempting to prove or disprove the use of an equation that was designed for fresh water to calculate the partitioning coefficent at different temps and how it can be used as salinity changes...

Filter paper or cloth would not work, it has to be liquid impermeable but gas permeable... the second any real quantity of liquid (above vapor) touches dryrite, it is an immediate exothermic reaction that turns dryrite into a solid block

 

 

[CaptainPanic]

I don't know then.

 

The addition of an antifoaming agent influences your measurements just as much as the removal of the organics... so I would go for the latter first:

 

Just avoid the foam at first... the Instant Ocean salts contain a lot of organic molecules. Try to imitate the salinity without the organics. That shouldn't foam.