Occasional use of Cuprisorb for heavy metals

[IamLoki]

Well here is my observation after another week if any of you are interested. I found the other snail and so far both are doing pretty well. They both moved to the back glass and have consumed all the spots of algae. They seem active and health so we'll see what another week brings.

I can say that adding Cuprisorb has helped with the snails thus far. They would usually be dead by now. I think the death of the first one was it may not have been healthy when I got it, or it fell on it's back and was attacked by some worms in the middle of the night.

This tank is 3 years old, maybe OTS and copper accumulation has some merit?

 

[Yogre]

My Cuprisorb is at the house, waiting for me. I plan to set aside a sample of tank water for ENC Labs, then start the Cuprisorb this weekend. I'll be curious to see if I can see any difference over time.

 

[tmz]

Glad to hear snails are doing better.

Metals build up overtime but they are bound by organics which in many cases are refractory( don't break down easily) and rendered harmless. Some of these bound metals are likely exported by the skimmer and gac unless for some reason the organics breakdown . An old sandbed or old tank syndrome are usually blamed and may have something to do with it but I'm not at all certain that's the case. It's free metals most notoriusly copper that do the damage. Salt mix might also be an issue or a failed ro di. Then again the snail deaths may e unrelated to copper entirely. In any case running al ittle cuprisoprb and or polyfilter doesn't hurt, ime. I like purigen too along with gac for organics removal.

 

[garbled]

I wonder if you can change the range of a hobby test kit by meddling with the amount of reagent/sample that is used with the kit. Perhaps getting 25 ml of sample instead of 5, and then boiling off 20 ml, then divide result by 5?

 

[HighlandReefer]

If you try this you would want to use a larger container to hold the sample to help prevent sample water from boiling out of the container.

I'm not sure if the organic copper would be converted to inorganic copper or ions of copper when you boil the sample. It would depend on what you test for Cu++, Cu+, other inorganic froms of copper, organic copper or total copper. Personally, I would test for total copper if that is available. Also any organism in the sample water would possibly release copper into the sample water when boiled, so you would most likely want to filter the sample water using a 0.25 micron filter. Hobby grade test kits usually test for only Cu++ IIRC.

Perhaps David may have some other suggestions from a Chemist's point of view.

 

[HighlandReefer]

One example regarding the complexity of the forms copper can take in marine water.

From it in part:
http://en.wikipedia.org/wiki/Copper

"Chemical

Unoxidized copper wire (left) and oxidized copper wire (right).Copper forms a rich variety of compounds with oxidation states +1 and +2, which are often called cuprous and cupric, respectively.[8] It does not react with water, but it slowly reacts with atmospheric oxygen forming a layer of brown-black copper oxide. In contrast to the oxidation of iron by wet air, this oxide layer stops the further, bulk corrosion. A green layer of verdigris (copper carbonate) can often be seen on old copper constructions, such as the Statue of Liberty, the largest copper statue in the world build using repoussé and chasing.[9] Hydrogen sulfides and sulfides react with copper to form various copper sulfides on the surface. In the latter case, the copper corrodes, as is seen when copper is exposed to air containing sulfur compounds.[10] Oxygen-containing ammonia solutions give water-soluble complexes with copper, as do oxygen and hydrochloric acid to form copper chlorides and acidified hydrogen peroxide to form copper(II) salts. Copper(II) chloride and copper comproportionate to form copper(I) chloride.[11]

IsotopesMain article: Isotopes of copper
There are 29 isotopes of copper. 63Cu and 65Cu are stable, with 63Cu comprising approximately 69% of naturally occurring copper; they both have a spin of 3/2.[12] The other isotopes are radioactive, with the most stable being 67Cu with a half-life of 61.83 hours.[12] Seven metastable isotopes have been characterized, with 68mCu the longest-lived with a half-life of 3.8 minutes. Isotopes with a mass number above 64 decay by β-, whereas those with a mass number below 64 decay by β+. 64Cu, which has a half-life of 12.7 hours, decays both ways.[13]

62Cu and 64Cu have significant applications. 64Cu is a radiocontrast for X-ray imaging, and complexed with a chelate can be used for treating cancer. 62Cu is used in 62Cu-PTSM that is a radioactive tracer for positron emission tomography.[14]"

 

[layer3switchguy]

I'd probably add some Chemi-Pure if I was losing a lot of snails shortly after buying them. A PolyFilter might be another option, since it'll turn blue if there's enough copper in the water, so it acts as a sort of minimal test kit.

Interesting thread... Has got me thinking that perhaps running an additive like this every 6 weeks or so may be beneficial to reduce possible copper/heavy metals?

Bertoni - would you suggest Chemi-Pure over Cuprisorb?

Thanks,
L3

 

[disc1]

You guys are on the right track about pre-concentration of the sample to get a higher level to test. Here's a book that might give you an idea how big of a topic that can be.

http://books.google.com/books/about/Preconcentration_techniques_for_trace_el.html?id=FV6z2VvHaVsC

You can't do it by boiling though. While you will get the volume of water down, you will probably also put your copper into insoluble states that may fool your test.

I'm a chromatographer, so my first choice is naturally going to be a column. It works kind of like the DI resin in your water purifier, except that the media will selectively chelate to copper. There are resins made specifically for this purpose. The book linked above lists some of them. A large volume of sample is passed over the resin and the copper is trapped there. Afterwards, the copper is eluted with a small volume of highly concentrated chelating agent like EDTA.

Not only does this get your copper concentrated, but it also removes most of the other ions from the saltwater. With those gone, we can play some solubility games to get it even more concentrated or remove the chelating agents. For example, we can precipitate the copper as the hydroxide, spin it out in a centrifuge, and then redissolve in a smaller amount of nitric acid.


Unfortunately, I don't think any of that can be done at home with commonly available items. About the closest we can get is the media in the cuprisorb.


In the lab setting, copper is usually pre-concentrated on column and then analysed by AAS or ICP-MS. Obviously the average reefer doesn't have access to those machines.

There are some really interesting electrochemical methods available as well.

In this book: Methods of seawater analysis By K. Grasshoff, Manfred Ehrhardt, Klaus Kremling

http://books.google.com/books?id=ep1A02HNlMIC&printsec=frontcover#v=onepage&q&f=false

Complexation and precipitation of copper onto an electrode followed by cathodic stripping voltammetry is reported as having a limit of detection of 0.1nmol/L (6.35 ng/L or 0.00000635 ppb).


I also recently saw a paper about selective precipitation titration of copper with sulfide using a sulfide ion selective electrode. I remember it had a low LOQ.

 

[disc1]

Does this kind of sound like the Salifert kit?

Sorry for the crummy OCR text. Try to read around it.



COLORIMETRIC DETERMINATION OF SMALL AMOUNTS

OF COPPER

Potassium Ethyl Xanthate Method

The method is based upon the fact that potassium ethyl xanthate produces
a yellow-colored compound with copper. The reagent added to a solution
containing traces of copper will produce- a yellow color var>''ing in intensity in
direct proportion to the amount of copper present. Larger amounts of copper
with the reagent produce a bright yellow precipitate of copper xanthate. Small
quantities of iron, lead, nickel, cobalt, zinc, or manganese do not interfere. The
procedure is especially valuable for determination of the purity of salts crys-
tallized in copper pans.

Special Solutions. Stock Solution of Copper Sulphate. 3.9283 grams
CuSOi-SHjO are dissolved in water and made up to a volume of 1000 cc. One
cc. is equivalent to 0.001 gram Cu.

Standard Copper Sulphate. Ten cc. of the stock solution are diluted to 1000
cc. with distilled water. One cc. =0.00001 gram Cu.

PotaBsium Ethyl Xanthate Solution. One gram of the salt is dissolved in
1000 cc. of water. The solution is kept in an amber-colored glass-stoppered
bottle.

Procedure. Five grams of the substance are dissolved in 90 cc. of water
(see note) and the solution poured into 100-cc. Nessler tube; 10 cc. of the potas-
sium xanthate reagent are added and the solution mixed by means of a glass
plunger. To a similar tube containing 50 or 60 cc. of water are added 10 cc.
of the xanthate reagent and then gradually drop by drop the standard copper
solution from a 10-cc. burette (graduated in -^ cc.) until the colors in both
tubes match.

If a = grams of the substance taken for analysis, 6=nimiber of cc. standard
copper solution required to match the sample; then 6X0.00001 X lOO-^-a =% Cu.

Notes. The amount of the substance to be taken varies according to its copper
content. The greater the copper contamination of the salt, the less sample required.
The solution should be neutral or only very slightly acid.



166 COPPER

In place of the Nessler tubes the special colorimetric apparatus described under
Titanium and under Lead may be used. A veiy weak copper standard will be
required for the comparison tube.

If the substance is insoluble in water the copper is rendered soluble by treat-
ment with nitric acid. Hydrochloric acid is added and the nitric expelled by evapo-
ration. The substance is taken up with water and the insoluble resioue filtered off.

Starch and organic matter are destroyed by addition of 10 cc. 10% sodium
hydroxide +10 cc. of saturated sodium nitrate solution, then evaporating to dryness
and igniting. Hydrochloric acid is now added to expel the nitric acid as direct^
above.

 

[tmz]

Chemi pure wouldn't adsorb the metals much if at all. It's just granulated activated carbon and some di resin . The esin is useless in saltwater applications. I'm sure Jonathan was thinking Cuprisorb and hjis fingers typed Chemi pure.

 

[Yogre]

^^^

Agreed, Tom, I think Jonathan meant Cuprisorb as well.

 

[HighlandReefer]

Thanks David for all the info.

 

[layer3switchguy]

Thanks guys! Not to hijack the thread, but what are the thoughts on running Cuprisorb say every 6 weeks for a 48 hour period just as a preventive regimen?

Would this be effective, or should it be run say for a week every 2 weeks?

 

[Yogre]

i'm not sure at this point there's a definitive answer. I'm going to run my Cuprisorb for a week, with samples sent to ENC Labs before and after.

My theory is that since the metals are building up over literally the course of years (my tank is 3 years old) just an occasional run every few weeks or maybe even 2-3 months will be adequate to keep this slow buildup in check.

Maybe Cliff and David could add some thoughts here, too.

 

[tmz]

I don't think anyone can answer that given the likely variability of any metals contamination from tank to tank . Not many I know of run it continuously or on a schedlued basis. At some point it might deplete something good, if a large quantity was used ; I suppose.

 

[layer3switchguy]

i'm not sure at this point there's a definitive answer. I'm going to run my Cuprisorb for a week, with samples sent to ENC Labs before and after.

My theory is that since the metals are building up over literally the course of years (my tank is 3 years old) just an occasional run every few weeks or maybe even 2-3 months will be adequate to keep this slow buildup in check.

Maybe Cliff and David could add some thoughts here, too.

Thanks for doing this! Please let us know the results!