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<div class="moz-cite-prefix">Aju Jugessur,<br>
Catalase has specifically evolved to breakdown H2O2<br>
with exceptional efficiency. However, it will likely lose<br>
effectiveness at low pH; it's optimum pH is 7.<br>
Since your solution is HF, I estimate solution pH 3-4.<br>
<br>
I'd estimate an approximate dose of NaOH to bring pH<br>
anywhere between 5 and 8. Then add bovine catalase so<br>
concentration is ~0.5 - 1 mg/l. <br>
<br>
Wiki has an interesting entry on catalase.<br>
I just learned why our hair turns gray.<br>
<br>
-------<br>
Can you share with the community the reason<br>
for tartaric acid in solution 3 or any related reference ?<br>
<br>
Sincerely,<br>
Bill Flounders<br>
UC Berkeley<br>
<br>
<br>
Jugessur, Aju S wrote:<br>
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<blockquote cite="mid:D470369E.A532%25aju-jugessur@uiowa.edu"
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Hi,</div>
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<br>
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I need some advice on waste disposal and management of the
following chemical mixtures:</div>
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<br>
</div>
<div>
<p style="color: rgb(0, 0, 0); font-family: 'Times New Roman',
serif; font-size: 12pt; margin: 0in 0in 0.0001pt 0.5in;
text-indent: -0.25in; background-color: white;">
<span style="font-family: Calibri, sans-serif;">1. 1 mM AgNO3
and 0.5 vol% HF</span><o:p></o:p></p>
<p style="color: rgb(0, 0, 0); font-family: 'Times New Roman',
serif; font-size: 12pt; margin: 0in 0in 0.0001pt 0.5in;
text-indent: -0.25in; background-color: white;">
<span style="font-family: Calibri, sans-serif;">2.</span><span
style="font-size: 7pt;"> </span><span
style="font-family: Calibri, sans-serif;">12.5 vol% HF, 3
vol% H2O2 and 84.5% deionized (DI) water</span><o:p></o:p></p>
<p style="color: rgb(0, 0, 0); font-family: 'Times New Roman',
serif; font-size: 12pt; margin: 0in 0in 0.0001pt 0.5in;
text-indent: -0.25in; background-color: white;">
<span style="font-family: Calibri, sans-serif;">3.</span><span
style="font-size: 7pt;"> </span><span
style="font-family: Calibri, sans-serif;">5ml HF, 30ml H2O2
, 48ml H2O/4.8g C4H6O6 (10%)</span></p>
<p style="color: rgb(0, 0, 0); font-family: 'Times New Roman',
serif; font-size: 12pt; margin: 0in 0in 0.0001pt 0.5in;
text-indent: -0.25in; background-color: white;">
<span style="font-family: Calibri, sans-serif;"><br>
</span></p>
<p style="color: rgb(0, 0, 0); font-family: 'Times New Roman',
serif; margin: 0in 0in 0.0001pt 0.5in; text-indent: -0.25in;
background-color: white;">
<span style="font-family: Calibri, sans-serif;">When we place
the above mixtures (2,3) in waste bottles, they still
generate some gases. E&HS refuses to pick up these
wastes until the reaction is complete.</span></p>
<p style="margin: 0in 0in 0.0001pt 0.5in; text-indent: -0.25in;
background-color: white;">
<span style="color: rgb(0, 0, 0); font-family: Calibri,
sans-serif;">It can take a while for the reaction to stop
releasing any gases and as a result the waste bottles sit in
our lab for a while until they are picked up. It is also not
practical</span></p>
<p style="margin: 0in 0in 0.0001pt 0.5in; text-indent: -0.25in;
background-color: white;">
and safe to keep opening the bottles to release the gas. We
are also running out of space to keep the waste bottles.</p>
<p style="margin: 0in 0in 0.0001pt 0.5in; text-indent: -0.25in;
background-color: white;">
<br>
</p>
<p style="margin: 0in 0in 0.0001pt 0.5in; text-indent: -0.25in;
background-color: white;">
I was wondering if there is a better way of managing these
specific chemical waste and also, whether there is a safe and
cost-effective way to stop the reactions (2,3) before we have
them picked up by E&HS. A quick search suggests Oxalic
acid to quench</p>
<p style="margin: 0in 0in 0.0001pt 0.5in; text-indent: -0.25in;
background-color: white;">
the H202 but we have a mixture of H202 with other chemicals.</p>
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<p style="margin: 0in 0in 0.0001pt 0.5in; text-indent: -0.25in;
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Thanks</p>
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background-color: white;">
Regards</p>
<p style="margin: 0in 0in 0.0001pt 0.5in; text-indent: -0.25in;
background-color: white;">
Aju</p>
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background-color: white;">
<br>
</p>
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<font class="Apple-style-span" color="#103ffb" face="Georgia"
size="2">Aju Jugessur <i>Ph.D.</i><br>
Director, University of Iowa Microfabrication Facility<br>
</font></div>
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widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;">
<font class="Apple-style-span" color="#103ffb" face="Georgia"
size="2">Professor (Adj.), Physics and Astronomy<br>
OSTC, Iowa Advanced Technology Labs<br>
University of Iowa</font></div>
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widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space;
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<font class="Apple-style-span" color="#103ffb" face="Georgia"
size="2"><br>
</font></div>
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<font class="Apple-style-span" color="#103ffb" face="Georgia"
size="2">205 N. Madison St</font></div>
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widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space;">
<font class="Apple-style-span" color="#103ffb" face="Georgia"
size="2">Iowa City, IA 52242<br>
319 -353-2342 <br>
<a class="moz-txt-link-abbreviated" href="mailto:aju-jugessur@uiowa.edu">aju-jugessur@uiowa.edu</a><br>
<a class="moz-txt-link-freetext" href="http://ostc.uiowa.edu/uimf">http://ostc.uiowa.edu/uimf</a></font></div>
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