Sulaiman
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How do YOU make pure water ?
In the thread 'Wanted References and Needed Translations' CJ provided yobbo ii with the file https://www.sciencemadness.org/whisper/files.php?pid=505736&...
Extracted from that, is this;
"House line distilled water was further purified by triple distillation:
first from acid chromate,
then from alkaline permanganate,
and finally from an all quartz still and collected in quartz containers."
I would have previously interpreted 'triple distillation' as just literally 'distilled three times' (e.g. whisky)
In a chem.lab. setting, does the above extract describe what is usually meant by 'triple distilled' ?
If so, what concentrations of additives should I use ?
Anyone have a link to a procedure ?
Would I need to dedicate one pot for each stage ?
I now buy my dH2O which so far has been pure enough for my needs, (e.g. no ppt. with AgNO3)
I have no simple method of testing for the purity of water at this level of purity, maybe Pt foil electrodes to measure conductivity, but I'd rather
not get that complicated, and it may be beyond my normal abilities.
I also currently have no quartzware and no need for such purity so its mainly an academic question,
but, as I do occasionally make my own dH2O
and a couple of times ddH2O for electrochemistry,
and I have the chemicals available,
I could incorporate this into 'normal' water distillations.
I guess one day I will want some ultra pure water, (in borosilicate !) which is why I ask.
________________________________________________
IF ever required, how have you personally produced 'pure' H2O
CAUTION : Hobby Chemist, not Professional or even Amateur
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wg48
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In chip fabrication they use PTFE to contain their seriously pure water. Quartz is soluble in water at about 10ppm at RT.
[Edited on 8-2-2018 by wg48]
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JJay
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In college, the labs mainly used water that was purified by reverse osmosis then electrolyzed. I usually just buy distilled water and use it mainly
for cleaning or when contaminants could end up in the final product. For many purposes, tap water is a minor source of contaminants.
If you are triple distilling water and washing your glassware with tap water, you are wasting your time; you probably ought to have a still dedicated
for each stage in the process.
Zone melting would probably work for preparing ultra pure water. It could be done with PTFE tubes.
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Reboot
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If you're looking for a general purpose grade of 'pure' water for dilution of reagents, washes, washing glassware, etc., a good option is a reverse
osmosis system with the output water passed through an ion exchange canister. It might not meet your needs if you're doing delicate analytical work,
but for most other things that's the easy way to go.
https://www.amazon.com/Express-Water-RODI10D-Deionization-Re...
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SWIM
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Quote: Originally posted by wg48  | In chip fabrication they use PTFE to contain their seriously pure water. Quartz is soluble in water at about 10ppm at RT.
[Edited on 8-2-2018 by wg48] |
So if I fill my big 1,000,000 ml polypropylene vessel with distilled water and throw a 10 gram quartz crucible in there, it'll dissolve?
Kind of surprising.
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unionised
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Eventually.
http://onlinelibrary.wiley.com/doi/10.1029/JZ069i010p01995/a...
Incidentally, the dehumidifier in my cellar churns out a slow stream of sub-distilled water.
If I was making pure water, I might start from that.
Distillation from acid permanganate is great- except you sometimes get chlorine in the product.
"pure water" is pretty much a myth.
What you do is target the purification to remove impurities you really don't want.
If I was doing trace organic work I might distil from permanganate or chromate- then from alkali.
But if I was doing trace metals analysis...
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j_sum1
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| Quote: Originally posted by SWIM | | Quote: Originally posted by wg48 | In chip fabrication they use PTFE to contain their seriously pure water. Quartz is soluble in water at about 10ppm at RT.
[Edited on 8-2-2018 by wg48] |
So if I fill my big 1,000,000 ml polypropylene vessel with distilled water and throw a 10 gram quartz crucible in there, it'll dissolve?
Kind of surprising. |
I suspect you would need some good stirring.
(Ref: magpie's sig.)
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Vosoryx
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I use my school's de-ionizer. The teacher lets me come in with a jug and fill it up when needed.
Never needed stupidly pure water, but it worked for hydrazine.
It shocks me that quartz is that soluble. Perhaps it would need to be ground into a powder, and, as jsum said, good stirring.
"Open your mind son, before someone opens it for you." - Dr. Walter Bishop
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LearnedAmateur
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| Quote: Originally posted by SWIM |
So if I fill my big 1,000,000 ml polypropylene vessel with distilled water and throw a 10 gram quartz crucible in there, it'll dissolve?
Kind of surprising. |
It does seem that way, but nature gets away with it in quite a beautiful form: the opal. Silica is dissolved from sandstone and other porous rock
where it finds a crack/fissure and settles. As the water evaporates away, the silica is deposited and crystallises over time, to be dug up and sold
with a hefty pricetag.
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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WangleSpong5000
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I distill filtered water usually. A high grade brita type filter removes the vast majority of ions then a simple distillation using properly cleaned
glassware and I'm happy with that. I usually just use de mineralised water for many things. It depends what I'm doing with it really...
Hyperbole be thy name
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likely_username
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I've honestly just started using tap water for 90% of my projects. A good portion of my reagents are technical grade anyway, and I've yet to have any
noticeable problem with contaminants introduced via tap water.
That being said, when I've done analytical work, we used a purification system that *started* with the house deionised water. Turns out DI water is
rather corrosive for sensitive equipment.
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DavidJR
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| Quote: Originally posted by likely_username | | I've honestly just started using tap water for 90% of my projects. A good portion of my reagents are technical grade anyway, and I've yet to have any
noticeable problem with contaminants introduced via tap water. |
That will, of course, depend on the hardness of your local water supply.
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WangleSpong5000
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Local supermarket no longer sells demineralised water. Was really pissed off until I realised they stocked distilled water all along! It was in the
aisle with all the bottled and mineral waters... it's awesome having litres upon litres of the stuff at all times and for very cheap.
Hyperbole be thy name
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ampHoteric
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While I was picking up some other odds and ends off Craigslist the seller threw in 35gallons of high purity water from Fisher for free. 
That’s for anything where I’m hyper concerned about purity so that’ll last me a good while. The rest of the time it’s distilled or even my
filtered tap depending on purpose.
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