Guy Macon's adventures with ultrapure water

[Ken Smith]

aren't you? I don't know what the "Quartz" is all about, but
it sounds like a great way to get dissolved silicon oxide in
your ultrapure water.

Take a slice of quartz and drill a hole this big:

 

[Winfield Hill]

Ken Smith wrote...

Take a slice of quartz and drill a hole this big:

UhHuh.
Exactly how big is this hole, and how do you reliably make
one, or more to the point, quadrillions of them? Right.

 

[John Popelish]

Ken Smith wrote...

UhHuh.
Exactly how big is this hole, and how do you reliably make
one, or more to the point, quadrillions of them? Right.

Excellent questions, but this is just about what they do to create
reverse osmosis membranes. I worked for a while in a plant that made
them (Permasep). The chemistry and processing is quite difficult to
get membranes with those quadrillions of correct sized holes. The
surface properties (hydrophilic versus hydrophobic) of the holes is
important also.

They use plastic materials not quartz, though.

 

[John Larkin]

It doesn't exist. You need to purify it on the spot. Ultrapure
water will dissolve anything it possibly can, and you want to give
it as little time leaching chloride from plastics and dissolving
metals and glass as possible. Making pure water is difficult,
and keeping it that way is impossible

Ice?

John

 

[The Phantom]

MIME-Version: 1.0
Content-Type: Text/Plain; charset=US-ASCII


(Keeping in mind that I am an electronics engineer with quite
limited knowledge of chemistry and some experience in designing
low-cost low-performance resistivity meters...)

I am after water with an R>18[Mohm/cm]

Water over 18.2Mohm/cm@25C doesn't exist. At room temperature
it spontaneously forms H+ and OH- Ions (and H3O+ Ions?
My memory fails me on that one).

Also, at what temperature? Ultrapure changes resistivity
4.5% per degree C @25C.

Also what is the best way of storing ultra pure water

It doesn't exist. You need to purify it on the spot. Ultrapure
water will dissolve anything it possibly can, and you want to give
it as little time leaching chloride from plastics and dissolving
metals and glass as possible. Making pure water is difficult,
and keeping it that way is impossible

Should I dispense it in to several small bottles with pipette lids?

No. To stay even close to 18.2Mohm/cm@25C you must start with
vacuum degassed ultrapure water and then never let it contact
air.

O2 dissolved in the water makes it better at attacking metals
(and lowering the resistivity) and dissolved CO2 will make
carbonic acid, which then attack the metal. You will get
lots of CO2 in the water even though the air doesn't have
much because CO2 dissolves so well, and ultrapure water has
little or no buffering capacity.

The pH of pure water is around 7 if I recall correctly, but
after being exposed to the air for a while the dissolved CO2
gives you a pH reading closer to 5. This will drop your
resistivity to somewhere in the 7 to 12 Mohm/cm@25C range.
Please note that measuring the pH of ultrapure water with
a pH sensor will not work right. Too little conductivity.

If this doesn't frighten you enough, do a Google search
on [ oligotrophic ultrapure ].

One site (http://aem.asm.org/cgi/content/full/68/4/1548) says "The extracellular
polysaccharide matrix acts as a diffusion barrier to nutrients and cellular products and
allows nutrients from the flowing water to reach bacterial cells"
^^ nutrients? What nutrients? It's just water with "... less than 1ppb
contaminants". Anything that can find nutrients there is going to be, as they say,
impossible to get rid of.

Better get some superbright

 

[Spehro Pefhany]

On Wed, 5 Jan 2005 02:22:05 +0000 (UTC), the renowned

Take a slice of quartz and drill a hole this big:

Kind of like RO, eh?


Best regards,
Spehro Pefhany

 

[John Woodgate]

I read in sci.electronics.design that Guy Macon <http@?.guymacon.com/>

Water over 18.2Mohm/cm@25C doesn't exist. At room temperature
it spontaneously forms H+ and OH- Ions (and H3O+ Ions?
My memory fails me on that one).

The hydrogen ion (H+) always attracts at least one water molecule
(H3O+), maybe more.

Also, at what temperature? Ultrapure changes resistivity
4.5% per degree C @25C.


It doesn't exist. You need to purify it on the spot. Ultrapure
water will dissolve anything it possibly can, and you want to give
it as little time leaching chloride from plastics and dissolving
metals and glass as possible. Making pure water is difficult,
and keeping it that way is impossible

Platinum bottles topped up with high-purity argon might keep it for a
while.

[snip]

The pH of pure water is around 7 if I recall correctly,

Yes, very close AFAIK.

but
after being exposed to the air for a while the dissolved CO2
gives you a pH reading closer to 5. This will drop your
resistivity to somewhere in the 7 to 12 Mohm/cm@25C range.
Please note that measuring the pH of ultrapure water with
a pH sensor will not work right. Too little conductivity.

If this doesn't frighten you enough, do a Google search
on [ oligotrophic ultrapure ]. Better get some superbright
UV lamps!

Quartz Triple distilled water

You are aware that distillation *concentrates* some impurities,
aren't you? I don't know what the "Quartz" is all about, but
it sounds like a great way to get dissolved silicon oxide in
your ultrapure water.

Quartz is a lot less soluble than glass. The trace of dissolved SiO2 may
not have much effect on the conductivity, since it doesn't ionize
appreciably.

 

[John Woodgate]

I read in sci.electronics.design that Winfield Hill <hill_a@t_rowland-

Ken Smith wrote...

UhHuh.
Exactly how big is this hole, and how do you reliably make
one, or more to the point, quadrillions of them? Right.

To spoil KS' joke, Google for 'molecular sieve' or 'osmosis'.

 

[John Woodgate]

I read in sci.electronics.design that The Phantom <[email protected]>

What nutrients? It's just water with "...
less than 1ppb contaminants". Anything that can find nutrients there is
going to be, as they say, impossible to get rid of.

Homeopathic metabolism! The bugs feed on what was dissolved in the water
BEFORE it was purified.

We are all doomed.

 

[Dieter Britz]

John, that's the most brilliant yet simple idea I have heard in
quite some time. Freeze the ultrapure water, and before you thaw
it saw away or melt away the outer layer. That sounds like it
would work.

I imagine the block of ice will be very, very clear.

This is the standard answer to the question, how do you contain
the universal solvent? In a container of the frozen solvent itself.

Sawing slices off the ice would again contaminate the water,
unless you use a Pt saw. I believe Wayne has limited means...

Wayne: I doubt that you can buy this pure water; you probably need
to get hold of a quarz triple stil, or permission ot tap from one.
Use quarz bottles (expensive) or teflon, as someone suggested. It
has also been mentioned that you quickly contaminate the water again,
initially with O2, CO2 etc from the air, then from the container walls
or residues on them.

Bockris and coworkers did some fine work in the '50's on solid
electrodes. Until then, people were saying that you can't do
useful work on them because of contamination, Hg was king, in
the form of the dropping mercury electrode, clean every time a new
drop comes out. They used the trick of distilling water and other
stuff (like HCl/water) directly into their cell. That way they got
around the storage problem. I don't know whether you can do that.

Deionised water might be free of ions, but it might also have
organic impurities. In our lab, we START with deionised water,
feeding it into our quarz stil. A key word (google!) is "pyrogens".

 

[Guy Macon]

MIME-Version: 1.0
Content-Type: Text/Plain; charset=US-ASCII


(Keeping in mind that I am an electronics engineer with quite
limited knowledge of chemistry and some experience in designing
low-cost low-performance resistivity meters...)

I am after water with an R>18[Mohm/cm]

Water over 18.2Mohm/cm@25C doesn't exist. At room temperature
it spontaneously forms H+ and OH- Ions (and H3O+ Ions?
My memory fails me on that one).

Also, at what temperature? Ultrapure changes resistivity
4.5% per degree C @25C.

Also what is the best way of storing ultra pure water

It doesn't exist. You need to purify it on the spot. Ultrapure
water will dissolve anything it possibly can, and you want to give
it as little time leaching chloride from plastics and dissolving
metals and glass as possible. Making pure water is difficult,
and keeping it that way is impossible

Should I dispense it in to several small bottles with pipette lids?

No. To stay even close to 18.2Mohm/cm@25C you must start with
vacuum degassed ultrapure water and then never let it contact
air.

O2 dissolved in the water makes it better at attacking metals
(and lowering the resistivity) and dissolved CO2 will make
carbonic acid, which then attack the metal. You will get
lots of CO2 in the water even though the air doesn't have
much because CO2 dissolves so well, and ultrapure water has
little or no buffering capacity.

The pH of pure water is around 7 if I recall correctly, but
after being exposed to the air for a while the dissolved CO2
gives you a pH reading closer to 5. This will drop your
resistivity to somewhere in the 7 to 12 Mohm/cm@25C range.
Please note that measuring the pH of ultrapure water with
a pH sensor will not work right. Too little conductivity.

If this doesn't frighten you enough, do a Google search
on [ oligotrophic ultrapure ]. Better get some superbright
UV lamps!

Quartz Triple distilled water

You are aware that distillation *concentrates* some impurities,
aren't you? I don't know what the "Quartz" is all about, but
it sounds like a great way to get dissolved silicon oxide in
your ultrapure water.

 

[Ken Smith]

[...]

Take a slice of quartz and drill a hole this big:

Kind of like RO, eh?

Very like RO. In RO, you drill little holes in some plastic so that only
liquid water can get through. Drilling the plastic is harder because the
little bitty drill bit get stuck more easily.

 

[Ken Smith]

Sawing slices off the ice would again contaminate the water,
unless you use a Pt saw. I believe Wayne has limited means...

If you used a water jet cutter running on ultra pure water, the
contamination issue could be solved.

 

[Ken Smith]

Quartz is a lot less soluble than glass. The trace of dissolved SiO2 may
not have much effect on the conductivity, since it doesn't ionize
appreciably.

Glass usually has metal impurities such as iron in it too.

 

[Spehro Pefhany]

On Wed, 5 Jan 2005 15:57:55 +0000 (UTC), the renowned

[...]

Take a slice of quartz and drill a hole this big:

Kind of like RO, eh?

Very like RO. In RO, you drill little holes in some plastic so that only
liquid water can get through. Drilling the plastic is harder because the
little bitty drill bit get stuck more easily.

<VBG>



Best regards,
Spehro Pefhany

 

[John Larkin]

Sawing slices off the ice would again contaminate the water,
unless you use a Pt saw. I believe Wayne has limited means...

Sublimate the outside in a vacuum, and use the core.

John

 

[Guy Macon]

Ice?

John, that's the most brilliant yet simple idea I have heard in
quite some time. Freeze the ultrapure water, and before you thaw
it saw away or melt away the outer layer. That sounds like it
would work.

I imagine the block of ice will be very, very clear.

 

[Guy Macon]

If this doesn't frighten you enough, do a Google search
on [ oligotrophic ultrapure ].

One site (http://aem.asm.org/cgi/content/full/68/4/1548)
says "The extracellular polysaccharide matrix acts as a
diffusion barrier to nutrients and cellular products and
allows nutrients from the flowing water to reach bacterial
cells" ^^

Nutrients? What nutrients? It's just water with
"... less than 1ppb contaminants".

It doesn't seem like it, but they do grow in ultrapure water.
One kind makes a living by grabbing the manganese from any
stainless steel it finds. Another grows (very slowly) these
fine white filaments that look like fine thread - I have seen
these growing in ultrapure water in a PTFE Teflon container.

Anything that can find nutrients there is going to be, as
they say, impossible to get rid of.

Not so. Bright UV lamps do the job. Then you have to
remove the tiny dead carcasses.

 

[Mike Engelhardt]

Ken,

[...]

Kind of like RO, eh?

Very like RO. In RO, you drill little holes in some plastic so that only
liquid water can get through. Drilling the plastic is harder because the
little bitty drill bit get stuck more easily.

But what if you use a thinner cutting lubricate, like
used for thread tapping instead of regular cutting oil.

Notice I didn't say that white cutting fluid that's
plumbed through machine shops. That stuff is water
soluble.

--Mike

 

[Guy Macon]

(Reposted from another thread...)

| From: Charles Jean <[email protected]>
| Message-ID: <[email protected]>
|
|
| >Can anyone advise where I can get Quartz triple distilled
| >water from (I'm in the UK) and what is it the best
| >conductivity you could expect from the most >purest water
| >
| >Also what is the best way of 1/ storing ultra pure water
| >and 2/ dispensing it so that the rest of the water does
| >not get contaminated. Should I >dispense it in to several
| >small bottles with pipette lids?
|
| Highest resistivity you can get is about 18.3 megohm-cm at
| 25 deg C. Self-ionization of water limits it to any higher
| value. This type of water can be produced by triple
| distillation in quartz apparatus or by mixed-bed
| deionization(much easier). Keeping it this way is tough,
| because it will have a tendency to dissolve the countainer
| it is in and absorb atomspheric gasses, especially carbon
| dioxide. I've seen a demineralizer setup that produced 18.3
| megohm-cm water(as measured by an in-line probe) that would
| measure around 5 after falling through about a foot of air!
| Purging the container with an inert gas, like argon would
| help with this, but then you'd have to he concerned about
| contaminants in the argon, etc. Some argon would dissolve
| in the water, but couldn't be measured by conductivity.
| Also there my be organic compounds present that can't be
| measured by conductivity. What is your application for this
| water?