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Dissolving copper

Dissolving copper - Chemistry Forum

Dissolving copper - Chemistry Forum. Discuss chemical reactions, chemistry.


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  #1  
Old 02-17-2004, 09:04 PM
Sam Hopkins
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Default Dissolving copper



Hi Everyone,

I just wanted to see if anyone knew what factors would affect copper
dissolving into a body of water. For instance if I purchased a piece of
copper pipe and attached a pump to and had it inside a 5 gallon fish tank
constantly pushing the same water through the pipe would the copper level of
the water increase? My understand from working with AMD is that the PH has
to be <7 for the copper to dissolve. Any higher and it precipitates out (or
doesn't even dissolve off the pipe).

Thanks,

Sam


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  #2  
Old 02-18-2004, 01:59 AM
Repeating Rifle
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Default Dissolving copper

in article c0tv12$4o1$[Only registered users see links. ].comms.marconi.com, Sam Hopkins at
[Only registered users see links. ] wrote on 2/17/04 1:04 PM:

I had a coworker who said that fish were extremely sensitive to copper. He
said that he was Harold Urey's student at one time. IIRC, they were doing
experiments to find out what heavy water did to fish. They had trouble
growing and maintaining fish because of copper plumbing. They may have been
recirculating the water using copper pipe.

I have no idea what bluestoning does to fish or what the copper
concentration is in comparison to what you get from copper pipe.

Try a Google or two.

Bill

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  #3  
Old 02-18-2004, 05:09 AM
Matt
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Default Dissolving copper

"Sam Hopkins" <[Only registered users see links. ]> wrote in message news:<c0tv12$4o1$[Only registered users see links. ].comms.marconi.com> ...

So long as you're not putting anything too bizarre in the water, the
copper piping should be fine. There are, that said, other things you
could use in place of copper if you were still worried about it.

Matt
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  #4  
Old 02-18-2004, 02:20 PM
N:dlzc D:aol T:com \(dlzc\)
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Default Dissolving copper

Dear Sam Hopkins:

"Sam Hopkins" <[Only registered users see links. ]> wrote in message
news:c0tv12$4o1$[Only registered users see links. ].comms.marconi.com.. .
of
has
(or

Notwithstanding any chemistry issues, flowing water through pipe causes
friction. Friction causes wear. Copper will be eroded into the water
stream. Common practice is to keep the velocity below 5 ft/sec in copper
pipe, to prevent excessive erosion. If you generate small enough "pieces"
of copper, they can be ingested.

Polyethylene is usually adequate for applications that normally use copper,
and is cheaper. Its failings are exposure to sunlight/UV, and high
temperatures.

David A. Smith


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  #5  
Old 02-18-2004, 06:43 PM
Marvin Margoshes
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Default Dissolving copper


"Sam Hopkins" <[Only registered users see links. ]> wrote in message
news:c0tv12$4o1$[Only registered users see links. ].comms.marconi.com.. .
of
(or

There is a special grade of copper tubing to hook-up refrigerators with
ice-cube makers. Using other copper tubing can result in green ice cubes!
I ran into such a case a couple of years ago. But plastic tubing is better.


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  #6  
Old 02-19-2004, 02:15 AM
Dale Trynor
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Default Dissolving copper



"N:dlzc D:aol T:com (dlzc)" wrote:


Dale Trynor wrote:
Don't forget that ammonia in water with air will dissolve copper and its basic.
Its also rather commonly made by bacteria on such things as fish waste.


I find that a bit surprising that mechanical corrosion would be a problem but I
suppose a dirty water supply would make this more likely. I have read that all
substances were soluble in water to some degree and when I first read about
this it was pointed out that the rusting of iron was usually accompanied by the
actual metallic iron itself as an actual water solution for a brief period of
time before it reverts to the oxide i.e., rust. Look at how the rust stains
form in a plastic bucket of water quite some distance from the iron itself.

Looking in one of my handbooks for the solubility's of various substances and
about the most insoluble was barium sulfate and its not completely insoluble
either. Oddly enough gold metal is so insoluble that its been pointed out that
the reason gold nuggets are usually so pure is because all the other metals
have literally leached or rather literally dissolved out, and this include
silver.

One of my engineering books listing the durability's of metals in salt water
listed copper as rather low in its durability and while I don't remember
exactly it suggested a lot of metal loss with rather little time. If you are
really interested I will look it up for you. Stainless is not so durable if no
oxygen is present such as where bacteria might be at work to use it up.
Titanium was about the best.

Don't forget that any copper in an aquarium may also need to deal with bacteria
at least someplace if not on it then nearby and their byproducts.


Plastic is almost assuredly better as I have seen or read recommendations
against the use of copper for aquariums etc. Copper compounds have been
recommended for use in anti fouling paints used on boats for this reason of
toxicity to marine life. Plastics can in many ways be considered a single
molecule or at least this is so in some cases, so I don't know how it could be
considered soluble at all and I also don't know what might be said of diamond.

I did my entire apartment in high density polyethylene and a bit was also done
with the earlier poly butadiene that has sense been taken of the market. They
both use the same connectors and both resist freeze and thaw damage which is
why I chose to use it. Don't confuse it with the PVC stuff that's also used in
plumbing but is not recommended to resist freeze thaw damage as far as I know
and I wouldn't use something just because its cheaper if its not also better.

The plastic plumbing I used requires some rather expensive twist on connectors
that in the end has resulted in costing me more than if I used copper but I
wanted the better quality and its easier to service etc. Because it goes in
faster labor might result in its being cheaper if you hire people to do the
installing and I never looked at that. Its available at the hardware stores
locally but still doesn't appear very popular , perhaps its just a mater of
education inertia I really don't know.


If you could find out how to use teflon tubing I believe its essentially
undamaged by terrestrial UV or at least I have been led to believe. Only
reference I have had for this is where it was used for solar collectors and no
ultraviolet inhibited stuff came close to the durability suggested of the
teflon and or related materials. Only other materials as durable was acrylic
and glass and both of those are brittle.

Teflon will take quite a bit of heat but one has more than one type to deal
with. Flexible polyvinyl chloride has plasticizes and I have read there are
more than one kind, that might have mystery properties that may or may not be a
problem depending on what its used for etc. Someone here will know more on this
than me.

Dale

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  #7  
Old 02-19-2004, 03:00 AM
N:dlzc D:aol T:com \(dlzc\)
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Default Dissolving copper

Dear Dale Trynor:

"Dale Trynor" <[Only registered users see links. ].ca> wrote in message
news:[Only registered users see links. ].ca...

A good complete answer, Dale!

....

You have not said it would, but I want to be clear since you brought up
fluoropolymers...
Do NOT use PVDF (Kynar(R)) where it can be exposed to UV.

David A. Smith


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  #8  
Old 02-19-2004, 07:08 AM
Charles
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Default Dissolving copper

On Tue, 17 Feb 2004 16:04:33 -0500, "Sam Hopkins"
<[Only registered users see links. ]> wrote:

Some thoughts:

Is this theory or practice?

I assume fresh water.

Is it hard water? hardness reduces the solubility of copper and its
deleterious effects on fish.

Has the water been chlorinated? Most dechlor products contain EDTA
which would tend to sequester any copper in the water.

Are there fish and plants? If so, there will be DOC which will also
sequester copper.

Will you be doing water changes? that will reduce the copper load,
assuming the replacement water is of adequate quality.


There is some information, and a lot of references, in Diana Walstad's
book, "Eco;logy of the Planted Aquarium." She says that copper and
other heavy metals come into solution with pH <5.5

Copper is bad, 0.02 ppm is a standard for fish, much lower than for
people, but aquarists used to put pennies in the tank to help prevent
algae.
--

- Charles
-
-does not play well with others
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  #9  
Old 02-20-2004, 04:12 PM
Sam Hopkins
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Default Dissolving copper

Well there's a discussion in the ornamental pond group about using copper as
piping in the filter system. Everyone claims not to do it because it'll kill
the fish, but when asked for a source it's always, "I heard" or "a friend of
a friend told me." I'm one not to believe anything until I see scientific
proof behind it. In any type of hobby group there's always a lot of info
that gets spread around and accepted as fact but never has been proven.

I know with dealing with AMD that getting the PH of the water > 7.0 percs
out the metals. Normal aquariums and ponds are PH > 6.5, and koi ponds are
usually PH > 8.4. My argument is this: What the heck did fish stores and
ornamental ponds use before PVC tubing?

I think I'll set this up and see if I can measure any copper in the water.

Sam


"Charles" <[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...
of
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  #10  
Old 02-20-2004, 04:32 PM
SNUMBER6
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Default Dissolving copper

>From: "Sam Hopkins" [Only registered users see links. ]


Copper is often purposely added at levels around 1 ppm to keep a pond algae
free ... The problem is keeping it in solution (not its accumulation) ... thus
necessitating the use of chelating agents like EDTA or TEA ...
othewise it will plate out on anything made of iron or just as an insoluble
hydroxide ...


Be seeing you
In the Village
Number 6

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