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<p class="MsoNormal"><span style="color:#1F497D">You might be seeing the same thing as we are experiencing. I am still at about 17.5 Mohm and it has been about 2 weeks since they changed out every DI resin bed. But it continues to climb back to the normal
18 Mohm ever so slowly. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Larry<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> Morrison, Richard H., Jr [mailto:rmorrison@draper.com]
<br>
<b>Sent:</b> Wednesday, June 05, 2019 12:00 PM<br>
<b>To:</b> Rehn, Larry A <lrehn@tamu.edu>; labnetwork@mtl.mit.edu<br>
<b>Subject:</b> RE: DI water Question<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">I just had the annual PM done I will look at the DI mixed bed rinsing.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Rick<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> Rehn, Larry A [<a href="mailto:lrehn@tamu.edu">mailto:lrehn@tamu.edu</a>]
<br>
<b>Sent:</b> Tuesday, June 04, 2019 3:39 PM<br>
<b>To:</b> Morrison, Richard H., Jr <<a href="mailto:rmorrison@draper.com">rmorrison@draper.com</a>>;
<a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
<b>Subject:</b> RE: DI water Question<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Hello Richard,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">We recently had our DI system sanitized by our service provider with a chlorine treatment. They used a chlorine color drop test indicator to determine that the chlorine was present at all drops in our system,
and then later to determine that it was rinsed to around < 1ppm. After that I was told that the DI resin beds would continue to remove remaining chlorine as indicated by the resistivity getting back into the Mohm range. We experienced a gradual climb in
DI resistivity from about 15Mohm up. Our service provider offered the following explanation (of why it did not immediately climb back to 18Mohm), which might be useful to answer your question about chlorine. The numbers he mentions refers to data in the
attachment.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in">….Usually, it means that a longer rinse should have been done on the regeneration, meaning that a very slight amount of regenerant hasn’t been fully rinsed out. I’ve attached one for the purpose of explanation.
Six Megohm is equal to 83 ppb and eight megohm is equal to 63 ppb, so we’re talking about t 20 ppb difference overnight. The difference between 14 megohm and 16 megohm is only 5ppb. I honestly believe that the quality will continue to climb very slowly and
reach it’s highest quality in the course of a few days. I’ve just seen this scenario too many times over the 30 plus years I’ve been working with high purity water.
<o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-left:.5in">FYI: When we regenerate the resin in our shop, we recirculate DI water for typically 24-48 hours through the separately regenerated cation and anion beds before we achieve the quality we desire, prior to mixing
it. I suspect very strongly that a batch didn’t get fully rinsed. Going back to the paragraph above, it comes down to ppb levels of regenerants (HCl and NaOH) that haven’t been fully removed through the resin. If you consume water throughout the day (which
in essence is the same as rinsing), along with constant recirculation, I truly believe the quality will climb.<o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">So, my interpretation is that maintaining high DI resistivity essentially guarantees that you will not have much chlorine in your water. Therefore, there may not be a need to make a separate measurement for
Cl-.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I agree that the ppm numbers you cite below seem high. Maybe I am missing something.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Larry A Rehn<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Technical Lab Manager<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">AggieFab Nanofabrication Facility<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Texas A&M University<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">979 845-3199<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><a href="mailto:lrehn@tamu.edu">lrehn@tamu.edu</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><img border="0" width="300" height="73" id="Picture_x0020_2" src="cid:image001.jpg@01D51BA1.0EB78350" alt="cid:image001.jpg@01CEC37D.FAF8C9E0"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> <a href="mailto:labnetwork-bounces@mtl.mit.edu">
labnetwork-bounces@mtl.mit.edu</a> [<a href="mailto:labnetwork-bounces@mtl.mit.edu">mailto:labnetwork-bounces@mtl.mit.edu</a>]
<b>On Behalf Of </b>Morrison, Richard H., Jr<br>
<b>Sent:</b> Tuesday, June 04, 2019 9:25 AM<br>
<b>To:</b> <a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a><br>
<b>Subject:</b> [labnetwork] DI water Question<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have a question about Chloride in DI water, the E1 water spec states 0.1ppm for Chlorides, have any of your operations monitor for this?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I had a test done and my6 redcir tank is 10ppm and the RO output is 25 these seem high to me, any data out there<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Rick<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Richard H. Morrison<o:p></o:p></p>
<p class="MsoNormal">Principal Member of the Technical Staff<o:p></o:p></p>
<p class="MsoNormal">Draper<o:p></o:p></p>
<p class="MsoNormal">555 Technology Square<o:p></o:p></p>
<p class="MsoNormal">Cambridge, MA<o:p></o:p></p>
<p class="MsoNormal">02139-3573<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Work 617-258-3420<o:p></o:p></p>
<p class="MsoNormal">Cell 508-930-3461<o:p></o:p></p>
<p class="MsoNormal"><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.draper.com&d=DwMFAg&c=ODFT-G5SujMiGrKuoJJjVg&r=viXbs6wGaGZ-o2y0LFbqZrWN_jy4Cw47zl8d3Wrr2M4&m=uLNn-r8zP-kxERCwIPXndhVVF0pihv0wAkHwnqmnSrY&s=1i1iCz-M3loX7C-Ak-x1sUCzjWrMQDtWIxVjSkL-vsg&e=">www.draper.com</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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