Keith,

We have successfully used a slight variation of the variable temp cryotrap
method of DesMarais (1978) [Anal Chem 50: 1405-1406] to separate SO2 from
CO2.  You can put the SS loop in rubber tubing, seal the ends with hose
clamps, and then immerse the whole trap in a dewar of LN instead of
building a vacuum chamber for the trap as Dave describes in his Anal Chem
article.  You must silver solder the proper thermocouple type to the bottom
of the SS loop prior to encasing the loop in the rubber tubing so that you
can read the temp of the trap.  We used a buck boost transformer hooked to
a variac to control the DC current going to the loop that warms the loop
against the LN, but I suppose you could use a temp controller if you could
find the proper model to control the temp at -140 C.  If you need any other
details, pls contact me directly.

Hope this is useful.

Bill

At 01:04 PM 5/6/99 +1000, you wrote:
>Dear Listmembers,
>                I am looking for any references you can recommend that
>refer to method(s) for removing H2S from CO2 in an on-line cleanup scenario.
>                One way that suggests itself to me is to pass the gas
>mixture over silver wool; reacting the H2S to Ag2S and forming hydrogen,
>the H2/CO2 mixture can then be cooled with LN2 to freeze out the CO2 for
>collection?
>                Thanks in advance for any help.
>                                         Keith Harris
>
----------------------------------------------------------
William J. Showers
Dept. of Marine, Earth, & Atm Sciences
North Carolina State University

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