Sciencemadness Discussion Board - Galvanic Cell Assisted New Path to CuSO4

Galvanic Cell Assisted New Path to CuSO4

AJKOER - 3-10-2018 at 13:28

BACKGROUND ON PRIOR CuSO4 PREPARATIONS
One prior cited path on SM refers to a video which employs conc H2SO4 and Cu plus heating to produce CuSO4 and some SO2 (see http://www.sciencemadness.org/talk/viewthread.php?tid=81115#... ).

From another thread (see http://www.sciencemadness.org/talk/viewthread.php?tid=29122 ):

Quote: Originally posted by TheChemiKid

Why don't you:
1) Boil Copper in Sulfuric Acid
2) Add Copper to mix of Hydrogen Peroxide (3% is adequate) and Sulfuric Acid
3) Electrolyze Sulfuric Acid with Copper and Carbon Electrodes

Also, from the same thread:

Quote: Originally posted by AJKOER

Try this, add copper to aqueous ammonia plus H2O2. Over night you will witness the formation of Cu(NH3)4(OH)2, in an aqua blue solution.

Now, add MgSO4 hydrate (Epsom salt). Filter out the white precipitate of Mg(OH)2. You now have Cu(NH3)4SO4. The last step is to destroy the NH3 by adding (speculation, I have not performed this part), say H2O2, and see if a massive amount of N2 is released with time (less than a day). Another possible way to remove the ammonia complex, just boil the solution (outdoors). Last suggestion, isolate the dry salt tetrammine copper(II)sulfate and heat. This would be the reverse reaction of its preparation, see http://www.google.com/url?sa=t&rct=j&q=tetra%20amine... There is some direct support for this method to remove ammonia based on a study (see http://www.google.com/url?sa=t&rct=j&q=thermal%20dec... ) of the thermal decomposition of Copper tetra ammine dithionate where ammonia is released in the early stage of decomposition.

If successful, the product is CuSO4 from simple available household chemicals.
……...
[Edited on 12-3-2014 by AJKOER]

Or, one could also treat prepared copper carbonate (see http://www.sciencemadness.org/talk/viewthread.php?tid=1605#p... ) or freshly formed by copper hydroxide or oxide (see, for example, http://www.sciencemadness.org/talk/viewthread.php?tid=84047#... ) with NaHSO4 to produce CuSO4 employing more time and reagents.

Proposed New Path To CuSO4 Via Copper/Noble Metal/3% H2O2/NaHSO4/Chelate for Cuprous (Lemon juice or sea salt)
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I prepared copper sulfate following a protocol discussed in a prior tread ( essentially a galvanic cell activating hydrogen peroxide in the presence of an acid source and the target metal for salt creation) which I believe will supplement the more standard chemical reactions occurring. The procedure consistent of adding a one inch piece of copper tubing used in plumbing and a more noble metal (in this case, I employed a commemorative thinly silver plated coin) to a solution of 120 ml of 3% hydrogen peroxide, and about 10 grams of sodium bisulfate and a small amount of a chelating agent for cuprous (best would be lemon juice as it is consumed especially if external air is used to supplement the use of H2O2, while sea salt a good chelator and electrolyte, used in my first run, may hinder the removal of Na2SO4 from the CuSO4 product). To remove the inception period, the aqueous mix was heated in a microwave for 1 minute.

Some of the expected chemistry:

2 x [ NaHSO4 (aq) = Na+ (aq) + HSO4- (aq) ]
2 x [ HSO4- (aq) = H+ + SO4(2-) ]

Cu = Cu+ + e-
e- + nH2O --> e-(aq)
H2O2 = H+ + HO2-
H+ + e-(aq) = •H
•H + HO2- = •OH + OH-

Memo: Net of last 4 reactions:
H2O2 + e-(aq) --> •OH + OH- (one electron reduction of H2O2)

And as the source of e-(aq) is copper:
Cu = Cu+ + e-

The net of the above two reactions parallels a Fenton-type reaction in copper:
Cu + H2O2 = Cu(+) + •OH + OH-
----------------------------------------

A similar system of reactions based on:
Cu(+) --> Cu(++) + e-
......

Additional reactions due to radical formation includes:
•OH + HSO4- = •SO4- + H2O
e-(aq) + •SO4- -->SO4(2-)
e-(aq) + •OH --> OH-

where the reaction Cu(l) + •SO4- --> CuSO4 has an expected reaction rate of k > 10^8 , based on p. 15 reported reactions by •SO4- acting on Fe(ll), Ce(lll), Cr(ll),.. at https://srd.nist.gov/NSRDS/NSRDS-NBS-65.pdf by Ross and Neta.

•H + •H = H2(g) (or H2S with possible small amounts of sulfide impurities present)
•H + SO4(2-) = OH- + SO3(2-) (a possible source of SO2 and perhaps more products)

Also, a decomposition reaction of H2O2 in presence of Cu2O/CuO (until attacked by H+):

2 H2O2 --Cu2O→ 2 H2O + O2

Approximate net reaction ignoring radical side reactions and copper oxide assisted self-decomposition of hydrogen peroxide:

Cu + 2 NaHSO4 (aq) + H2O2 → Cu(2+) + 2 Na+ + 2 SO4(2-) + 2 H2O

Note: per the above net reaction, Na2SO4 (as can be collected as a hydrate upon freezing absence the presence of chloride) molar concentration should be approximately twice as much as the CuSO4.

Also, one can reduce the need for H2O2 by using an air pump as:

4 Cu+ + O2 (from air) + 2 H+ → 4 Cu2+ + 2 OH- (Source: See, for example, https://en.wikipedia.org/wiki/Copper(I)_chloride )

EXPERIMENTAL RESULTS USING SEA SALT
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Following the mixing of ingredients and a brief period of 60 seconds in a microwave, a vigorous reaction occurred for 10 minutes, abated to some extent and visually continued some hours (see attached pictures). At commencement, within minutes the starting copper metal, which had some discoloration from prior experiments, became pristine clear. Also, an obvious blue coloration rapidly became evident consistent with the formation of copper sulfate. At the end of the reaction (exhaustion I suspect of the H2O2 from several paths), a close examination of the solution also indicated the formation of a tiny amount of a fine suspension (Na2SO4 salted out?). Upon opening the vessel there was evident of a small amount of an odorous gas as well (possibly SO2 and/or H2S from sulfur impurities). After several hours, the reaction have ceased leaving copper metal (the anodic zone in the galvanic cell) discolored. Following the addition of 70 ml more of 3% H2O2, in approximately 20 minutes the copper metal again became pristine clear. After 6 hours, I decided not to reheat the solution (which remained warm to the touch), and terminated the experiment. Upon decanting the aqueous CuSO4/Na2SO4 solution, it was frozen but unable to isolate the Na2SO4 hydrate likely due to the presence of NaCl.

[Edited on 4-10-2018 by AJKOER]

[Edited on 4-10-2018 by AJKOER]

symboom - 3-10-2018 at 13:35

Magnesium sulfate and oxalic acid forming insoluble magnesium oxalate decant off magnesium oxalate then add copper hydroxide to form copper sulfate I don't see how this would not work

[Edited on 3-10-2018 by symboom]

AJKOER - 3-10-2018 at 13:37

Starting picture before placing in microwave.

Second, is upon exiting of the microwave.

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AJKOER - 3-10-2018 at 13:45

Picture 40 minutes later.

Second picture is after adding more H2O2 towards end of experiment.

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[Edited on 3-10-2018 by AJKOER]

AJKOER - 3-10-2018 at 13:56

Quote: Originally posted by symboom

Magnesium sulfate and oxalic acid forming insoluble magnesium oxalate decant off magnesium oxalate then add copper hydroxide to form copper sulfate I don't see how this would not work

[Edited on 3-10-2018 by symboom]

Thanks for the comment.

With respect to your comment, yes, quite possibly, but one has to have H2C2O4!

A word of warning, I did not store my toxic Oxalic acid in the refrigerator and over a hot summer, it decomposed on me!
Perhaps a quality issue, but my point is H2C2O4 may not be available and it is, in any event, more costly than NaHSO4.

AJKOER - 4-10-2018 at 06:40

Re do with no NaCl but a few crystals of citric acid, H2O2, noble metal (a coin), NaHSO4 and application of an air pump to a piece of copper metal.

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[Edited on 4-10-2018 by AJKOER]

Amos - 4-10-2018 at 15:45

Quote: Originally posted by symboom

Now I've not tried this myself, but the reaction you describe between magnesium sulfate and oxalic acid is an equilibrium one; magnesium oxalate will certainly dissolve to a degree in sulfuric acid to illustrate the reverse, and with sulfuric acid being the much stronger acid and dissociating fully while oxalic will not, it should definitely lean towards re-forming magnesium sulfate. In theory at least, all you'll end up with by trying this is dilute sulfuric acid highly contaminated with magnesium sulfate and oxalic acid.

symboom - 4-10-2018 at 16:55

It's always the simplest that never solver complex things it would be nice if it worked but I don't think the equivalent is not possible like the quick and dirty nitric acid way with calcium nitrate and sulfuric acid.
citric acid, H2O2, noble metal (a coin) what is the coin made out of. Catalysts? copper citrate nice and simple.

[Edited on 5-10-2018 by symboom]

AJKOER - 6-10-2018 at 19:57

Coins can be made of an alloy of copper and nickel and are designed to be corrosive resistance. In fact, if it isn't corrosive resistant upon testing in circulation, it is likely redesign to be such. The goal is low cost and a low anodic index for an extended longevity.

Here is an example of an anodic index chart, see http://easternanode.nf.ca/anodic.php , note the alloys!
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[Edited on 7-10-2018 by AJKOER]

symboom - 6-10-2018 at 20:44

Thanks copper nickel alloy is great to dissolve it leals the surface really shiny like a looks almost a white platnium
I especially like nickel more than copper. I dissoled a copper nickel coin with oxone and vinagar smelled strong but etched the surface nicely