I have Ar/N2 cylinders that have a moisture concentration of 20 PPM. I have to reduce that down to 10 PPB. Is there any suitable setup or moisture scavengers, that should be used?
Let the gas pass a trap cooled by liquiid nitrogen, it should be safe.
We use a Nafion loop from Perma-Pure. It uses a counter-flowing stream of dry industrial nitrogen to remove moisture. You can also set it up in a reflux loop to use without the nitrogen. You can remove virtually all the moisture from a sample stream (our sample flow rate is 100-200 mL/min). A less expensive alternative is a canister of magnesium perchlorate, but you have to keep changing it.
A liquid nitrogen trap as Christer suggested is good. We use that in noble gas mass spectrometry. Though I'd suggest using a Pyrex U-tube for the trap. It is easy to clean. I use that when I have to analyse noble gases in water samples after each expt I dry the pyrex tube with a hair blower.
if you do not have access to liquid nitrogen, dry ice (solid CO2) should do the job.
You have to use a moisture filter. It depends on the configuration of your system but there are severeal posibilities. Ask your supplier. For example, you cuold use a palladium filter or a filter with zeolites...
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