[Ifeffit] Preparation help with fly ash sample with diluted Tl

[Mengling Yi Stuckman]

Thank you so much!

This is the first time I tried to use ifeffit mailing list. I would have
never expected so many responses from so many scientists. I wish one day I
could be able to contribute back to this great scientific community as well!

Thanks again!
Mengling

On Thu, Sep 29, 2011 at 8:00 PM, Matt Newville
<newville at cars.uchicago.edu>wrote:

> Hi Mengling,
>
> 2011/9/29 Mengling Yi Stuckman <stuckman.12 at osu.edu>:
> > Thanks for all the response! They are all very helpful!
> > Just want to make sure that I get the information right and a few
> follow-up
> > questions:
> > 1. I'd better contact the beamline engineer to ask for the sensitivity
> for
> > Tl.
>
> Yes!
>
> > 2. Fe fluorescence interference could be decreased by adding a few layer
> of
> > Al foil. I knew that I did that when I measured As fluorescence. So this
> is
> > ok.
>
> Yes.
>
> > 3. Pb fluorescence interference is very hard to eliminate. Therefore,
> EXAFS
> > for Tl is very hard to get. Actually, I didn't see any papers on Tl EXAFS
> > and maybe that is why. The research question I want to answer is:
> > what structure Tl is bond to in the fly ash? Tl(I) and Tl(III) could
> > theoretically bind to sulfate, nitrate, bicarbonate, etc.. I saw some
> papers
> > that are using nitrate, sulfate, bicarbonate Tl salt as references for
> > micro-XANES measurement. And then they compared the XANES in the end. Is
> > that a better approach than EXAFS to answer the question?
>
> Well, maybe not "better", but generally tolerant of less good data.  And
> also generally more "directly sensitive" to oxidation state and ligand.   I
> won't kid you though - Hg, Tl, and Pb L3 XANES can be tricky to analyze
> well, as the features are not very well resolved.
>
> > 4. To increase the intensity, we can condense the ash by pressing it into
> > pellet. The fly ash from coal combustion power plants are already pretty
> > compacted. They are mainly gypsum in most cases. I dont' know if that
> helps
> > or not.
>
> It won't hurt.
>
> > 5. This is the first time I heard about non-energy dispersive detector,
> e.g.
> > PIPS diode. We are planning to use 13-element detector. What is the
> > advantage of using one way or the other? If I do want to concentrate on
> > XANES, would be helpful to ask the beamline engineer for the possibility
> of
> > changing detectors?
>
> I'd start with the 13-element Ge detector and see how that goes....
>
> Cheers,
>
> --Matt
>
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-- 
Mengling Yi Stuckman
Graduate Research Assistant
Civil and Environmental Engineering and Geodetic Science
Ohio State University
2070 Neil Ave., Columbus, OH, 43210
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