Sciencemadness Discussion Board - Sodium hydroxide and metals clorides from salt using polypropylene diaphragm

Sodium hydroxide and metals clorides from salt using polypropylene diaphragm

Hexabromobenzene - 6-2-2025 at 02:48

This is a test diapragm from this topic
https://www.sciencemadness.org/whisper/viewthread.php?tid=16...

About 330 grams of sodium chloride dissolved in 2 liters of water. Solution was poured into a 5 -liter polypropylene container and a diaphragm made as written in the topic about diaphragms. Cathode solution was diluted to equalize fluid levels
Anode is iron scrap. Cathode stainless steel from the hose from the shower. Voltage 5 volts. Current 1a. At the end of the electrolysis, it fell to 0.8 amperes. Electrolysis time 6 days
Diaphragm was quickly extracted from the electrolyzer to prevent leakage.

Diaphragm was clogged with iron hydroxide, but then washed with acid. This did not have effect on conductivity
Cathode solution was filter and was evaporated to a density of 1.3. About 70 grams of salt fell in the precipitate. 270 ml of alkali solution of about 30% was obtained. About 100 grams of sodium sodium hydroxide total

Anode solution was also filtered and evaporated. In the process of evaporation, hydrolysis and corroding of metal containers occurs. After drying, 230 grams of wet crystals were obtained. Iron chloride 2 is highly polluted by sodium chloride by this results preliminary. Also, iron chloride is oxidized in the air

Iron chloride 2 has little value, but can be used to prepare iron benzoats and obtaining, for example, acetophenone
Other chlorides can be prompted in the same way. For example, zinc chloride. The method does not require acids and gives a side alkali.
You can also get chlorine
In the process of electrolysis, there were no damage to the diaphragm. This can work for a very long time

[Edited on 6-2-2025 by Hexabromobenzene]

Hexabromobenzene - 25-6-2025 at 14:20

Using a polypropylene diaphragm, about 1 kg of sodium hydroxide, a liter of a zinc chloride with a density of 1.5 and about 1 kg of iron chloride 2, which is oxidized in the air, was prepared.
A lot of liquid flows through the polypropylene diaphragm. Do electrolysis with the maximum current as much as possible to increase the output and avoid clogging. Also, do not immerse deep into the solution of the metal anode to reduce the metall dissolution current yield

[Edited on 25-6-2025 by Hexabromobenzene]

Hexabromobenzene - 17-8-2025 at 14:52

Experiments confirm this again
Do not immerse the anode to the full depth. This will lead to the formation of a large amount of sediment. Immerse at minimum possible depth. Use ammeter. Watch when the current starts to go to the plateau. As the anode destroys and current falls significantly, immerse new parts
These measures will lower current yield of electrochemical destruction of the anode
This is all connected with diffusion ions
Area of the anode should be many times smaller than the area of the cathode

In theory of 1 faraday of the charge (26.801 A·h) decomposes 2 mol sodium chloride(~118gr) in case brine in both anode and cathode chamber

Because when the mol of the charge is flowing, one mol of sodium ions passes into a cathode chamber forming a mole of sodium hydroxide and mol of chloride ions go into the anode chamber forming another mole of sodium hydroxide in cathode chamber. Sodium and chloride have a charge 1

[Edited on 17-8-2025 by Hexabromobenzene]

Hexabromobenzene - 21-8-2025 at 18:02

Interesting data from
https://beta.iopscience.iop.org/article/10.1149/1.3493888
On the formation of ozone and peracids. I confirm the strong smell of ozone during the electrolysis of sulfuric acid with small-area electrodes

Quote:

The potential of the lead anode in the electrolysis of an aqueous Na2 SO4 solution is usually above 2 volts (see below). Therefore, besides the main process of OH- discharge there may be, according to Le Blanc,13 when the anodic potential is above 1.75 volts, a discharge of SO4 - - ions followed by the formation of new oxidation products such as persulfates. The presence of any such by-products in the anolyte was determined by us in the following manner : (a) In the first sample of carefully filtered anolyte we tested qualita- tively for lead and got a negative result b) In the second parallel sample the content of peroxide com- pounds was determined by the ferric sulfate method. The values found were calculated as persulfuric acid and from this figure the per cent current loss due to H2S2O8 formation was computed

On the effects of chloride pollution

Quote:

If any chlorine ions are present in the solution, the destruction of lead anodes is markedly increased due to relatively rapid intermediate formation of PbC12 . The PbC1 2 formation takes place in spite of a higher required potential than the normal oxygen discharge potential, due to a high oxygen overvoltage together with the depolarizing action in the formation of PbC1 2 . The net chlorine ion discharge potential is less than that for oxygen. Le Blanc13 reported that in the electrolysis of HC1 no chlorine gas is discharged if the chlorine content of the electrolyte is less than 2.08 g./L. However, this was based on laboratory experiments, and in com- mercial cells with relatively high anode current densities and effective anode depolarization the maximum Cl' content will be lower. At a current density of 520 amp./m. 2 and a H2 SO4 concentration in the anolyte of 200 to 300 g./L., the maximum Cl' concentration as deter- mined by us was 0.15 g./L. ; below this concentration no Cl' is dis- charged and there is no serious corrosion of the anodes such as occurs above this concentration.
The data obtained (Table X) show that : (1) the addition of Sb to
lead in amounts up to 11 per cent does not increase the stability of lead
anodes; at high current densities it even diminishes it; (2) the presence
of Cl' in the electrolyte in amounts higher than of 0.1 g./L. increases
considerably the corrosion loss of the lead anodes ; at high current den-
sities the PbCl2 is not formed fast enough and a certain amount of
chlorine is liberated as gas with the oxygen. Therefore, in the presence
of Cl' the destruction of the lead anodes is greater at low current den-
sities; (3) the best results as to stability and anode corrosion resistance
are obtained with the anodes made of an alloy containing 99 per cent
Pb and 1 per cent Ag 1

clearly_not_atara - 22-8-2025 at 15:20

One interesting question in this rxn is what metal should you use for the anode so that you can most easily distill off hydrochloric acid? We know that some metal chlorides decompose to oxychlorides or hydroxychlorides when dried from aqueous solution. If it is the HCl we are after then we want a metal that releases HCl to as great an extent as possible at as low of a temperature as possible. For iron (III) chloride we get two-thirds of the chloride back at 250-300 C, but we are stuck here until around 400 C:
https://link.springer.com/article/10.1007/BF01979262

For zinc chloride we are at 87% at 300 C but water vapor must be present or ZnCl2 will be volatilized (?!):
https://pubs.rsc.org/en/content/articlehtml/2000/pv/c5dt0486...

For aluminum I am not sure.

and for zirconium oxychloride we obtain nearly all of the chlorine at just 200 C in "moist helium" for which I suppose probably another wet atmosphere could probably be substituted:
https://pubs.acs.org/doi/pdf/10.1021/ic50129a045 (attached)

Zr is a particularly attractive anode for this rxn although the price or difficulty of acquisition may preclude its use.

Attachment: powers1973.pdf (808kB)
This file has been downloaded 166 times

Hexabromobenzene - 23-8-2025 at 01:49

Oops. I was mistaken in the topic by writing the answer above

I believe that metall chlorides themselves valuable. To release hydrochloric acid from them, you will need special equipment. Metals will corrode in these conditions
On the other hand, a lot of sediment is formed on the walls of the diaphragm, which slowly moves to the anode, the composition of which has not been studied. Maybe this is oxichlorids?

About of chlorides. Electrolysis on iron anode gives only iron chloride 2 without impurities of iron chloride 3. But it can be oxidized in iron chloride 3, for example, electrolysis on an inert anode
The precipitate from iron is also formed very hard. Maybe these are oxichlorides?
The hydrate of zinc chloride is quite stable and it can even be completely dried with calcination. Part to decompose into oxichloride
Also falling out components from the alloy. For example micropactricles copper from a zamac alloy or graphite from steel or other components, for example, from silicon impurities in stell

Large crystals are released from the solution of iron chloride when dried in air. While the solution is noticeably oxidized
A solution of zinc chloride after electrolysis is not crystalized even after several months of evaporation. It can be concentrated even to the density of 1.6
I have no experience with other chlorides

[Edited on 23-8-2025 by Hexabromobenzene]

clearly_not_atara - 23-8-2025 at 09:12

It would be interesting to see if VCl2 or CrCl2 are produced here. These are reducing agents. Both solutions will be vulnerable to aerobic oxidation.

I think you can dry them by:

- concentrating the solution (or crystallizing the salt hydrate I don't know exactly)

- adding methanol

- drying the methanol selectively somehow (not sure if this is necessary)

- boiling off methanol in inert atmosphere

I know you can make anhydrous FeCl2 like this.

Hexabromobenzene - 11-9-2025 at 17:59

I prepared more than 2 kg of sodium hydroxide in this way. I can’t understand why even when using 2 identical containers, I get an yields only 30% by sodium chloride. I cannot exceed this magic number even with an excess of electricity. Maybe the anode container should be larger, since at the end it is noticeable depletion of the liquid in it is likely due to the formation of metal hydroxide
Perhaps using two and three stages ionization salts like sulfate or phosphate will increase efficiency

I use a voltage of 5 volts and I need about 5 kWh to obtain 1 kg of sodium hydroxide. It's still cheaper than alkali in the store
I can’t use 3 volts in this synthesis due to the fact that I need to reduce anode surface to prevent formation of hydroxide. Perhaps I can reduce the voltage when preparing chlorine, but inert anodes are needed. I can also use ethanol as a substrate for the disposal of chlorine, but I do not know what to do with large quantities of dangerous chloroacetaldehyde. Chloral is formed only at high temperatures

This method require a volume of about 20 liters to obtain a significant amount of alkali per launch. As an alternative, you can boil sodium carbonate and calcium hydroxide, but this method also has disadvantages. You need to evaporate a lot of water and sodium carbonate is more expensive than salt

[Edited on 12-9-2025 by Hexabromobenzene]

Hexabromobenzene - 28-9-2025 at 11:20

Quote: Originally posted by Hexabromobenzene

Experiments confirm this again
Do not immerse the anode to the full depth. This will lead to the formation of a large amount of sediment. Immerse at minimum possible depth. Use ammeter. Watch when the current starts to go to the plateau. As the anode destroys and current falls significantly, immerse new parts
These measures will lower current yield of electrochemical destruction of the anode
This is all connected with diffusion ions
Area of the anode should be many times smaller than the area of the cathode

In theory of 1 faraday of the charge (26.801 A·h) decomposes 2 mol sodium chloride(~118gr) in case brine in both anode and cathode chamber

Because when the mol of the charge is flowing, one mol of sodium ions passes into a cathode chamber forming a mole of sodium hydroxide and mol of chloride ions go into the anode chamber forming another mole of sodium hydroxide in cathode chamber. Sodium and chloride have a charge 1

[Edited on 17-8-2025 by Hexabromobenzene]

Most likely my conclusions are incorrect. 1 Farad will transfer 0.5 mole of ions from each compartment forming 1 mol of alkali and metal chloride

Hexabromobenzene - 3-10-2025 at 16:05

I've accumulated a lot of iron chloride 2 from electrolysis. Zinc chloride can be used in organic synthesis. Iron chloride 2 is useless. However, I found that iron chloride 3, when heated to 190°C, yields two-thirds hydrochloric acid and iron oxychloride, which can also be converted to chloride.

[Edited on 4-10-2025 by Hexabromobenzene]

RU_KLO - 9-10-2025 at 11:48

You could use ferric chloride for PCB etching....

Hexabromobenzene - 12-10-2025 at 17:29

I don't etch circuit boards. I have lots of iron chloride, but I'm always short of acids.

I just tried electrolysis with potassium chloride under similar conditions. The same concentration as sodium chloride and a slow iron anode immersion. The conductivity doubled.
And this isn't a saturated potassium chloride solution. But I don't want to use strong solutions because of the risk of crystallization.

With an iron anode, the current immediately drops significantly upon slow immersion, unlike with a zinc anode, and I don't know why.

I was also able to evaporate zinc chloride after electrolysis to a density of 1.56 without the chloride crystallizing.

[Edited on 13-10-2025 by Hexabromobenzene]

bnull - 12-10-2025 at 17:34

You could sell iron(ii) chloride. It is useless for you, so you can sell it relatively cheap.

Hexabromobenzene - 20-10-2025 at 06:22

Sodium chloride electrolysis lasted 7 days(200-300 amp hours), but the yield was still 200-250 grams of sodium hydroxide per 900 grams of salt. I think 30% is the limit of this process.
However, the alkali yield is much higher than with sodium sulfate electrolysis using a lead anode. This can be explained by the fact that there are no hydrogen ions in the anode chamber, only iron ions. And iron ions cannot enter the cathode chamber. This is why the resistance of the electrolyzer increases towards the end. In other words, the neutral layer in the diaphragm acts as an ion-exchange resin.
This also perfectly explains the fact why almost no salt is found in the anode chamber after evaporation.
Also zinc partially penetrates the cathode chamber, likely as zincate. Unlike iron, which is not detected there.

The deposit on the diaphragm walls is magnetite, not iron hydroxide II. Apparently, iron hydroxide II quickly decomposes under these conditions and forms a dense mass. Other metals form larger deposits and reduce the space available in the anode chamber.
I'm currently experimenting with potassium chloride and potassium sulfate. We'll see what yields they produce.

Quote:

You could sell iron(ii) chloride. It is useless for you, so you can sell it relatively cheap.

It's too expensive for me. I produce chemicals for myself. I don't have any plans to ship it yet.

[Edited on 20-10-2025 by Hexabromobenzene]

Hexabromobenzene - 22-10-2025 at 00:45

Potassium chloride experiment is complete. From 850 grams, 470 ml of hydroxide solution with a density of 1.4 was obtained. Some liquid remained in the precipitated salt. Given that the molecular weight of potassium hydroxide is higher, the current efficiency is approximately the same NaCl runs.

Hexabromobenzene - 9-11-2025 at 15:11

Experiment with potassium sulfate is coming to an end. It's a byproduct from wood ash like potassium chloride. This salt is very poorly soluble, and because the solution was diluted, large volumes had to be used, and need voltage 12 volts.
However, the iron salt method yields very high current yields compared to others. All these factors contribute to this. The iron hydroxide barrier and the fact that the anode liquid level is always higher than the cathode liquid.

I think to obtain acid it is better to first make iron, zinc, aluminium salts and then prepare acid from them than to do electrolysis of, for example, sodium sulfate.

[Edited on 9-11-2025 by Hexabromobenzene]

Hexabromobenzene - 11-11-2025 at 21:09

Experiment with potassium sulfate is completed. 320 ml of KOH solution with a density of 1.51 was obtained. There was a total of 900 grams of potassium sulfate in 2 runs (550 and 350 grams). Yield is 43% but taking into account losses it can be considered 45%. The amount of current is approximately 2 faradays per mole of potassium sulfate
Towards the end of electrolysis, stalagmites of iron hydroxides were discovered that go from the diaphragm to the anode
Very good result. To improve the output, I think the cathode compartment should be less than the anode compartment by about 0.5-0.7 volume. Transfer of ions from the anode space is carried out with very high efficiency since very few salts are found in the anode compartment. You should also not use concentrated solutions due to loss of solution in the sediment in the anode compartment.

Sulfuric acid can be very easily obtained with high current efficiency by electrolysis of iron sulfate in a diaphragm electrolyzer

[Edited on 12-11-2025 by Hexabromobenzene]

Hexabromobenzene - 2-12-2025 at 16:51

Interesting fact. At a very high current density, if you use a voltage of 12 volts, the formation of ferric chloride 3 begins and even the SMELL OF CHLORINE is observed.

At the moment I am doing one last test in an attempt to find out the maximum NaOH yield from salt by d this diaphragm method. A diluted salt solution of 100 grams per liter is used to prevent crystallization in the anode chamber. Do not use saturated solutions, otherwise this will inevitably happen.

[Edited on 3-12-2025 by Hexabromobenzene]

Hexabromobenzene - 6-12-2025 at 05:20

From 250-290 (uncertainty due to alkali impurities) grams of sodium chloride in a dilute solution and with excess current, 80 grams of sodium hydroxide are obtained. Yield 35-40%
Apparently 40% is the physical limit
It was also noticed that a large volume of iron hydroxide precipitate is formed. The neutral zone moves behind the diaphragm into the anode chamber
Next experiment will be carried out with an ion exchange diaphragm

I don’t fully understand what the output will be with the diaphragm. If we have sodium chloride in 2 chambers, then the yield in theory is 200%, but immediately a sharp increase in the concentration of chloride and sodium ions in the anode and cathode chambers begins, respectively, and the yield drops. The final yield is 2 times less. However, we have iron salts in the anode chamber that cannot leave it, which means the yield will be stable until sodium has completely moved from anode chamber, sodium plus chloride from the cathode chamber.

An ion exchange membrane can only allow one type of ions to pass through, which means it makes no sense to add sodium chloride to the cathode chamber, but then the yield drops.

I don't understand how this works

bearbot22 - 7-12-2025 at 14:57

Hexabromobenzene, your assumption is correct.
According to Wikipedia, in the chloralkali process with Nafion membrane, NaCl electrolyte is used in the anode half-cell only. The cathode half-cell contains (almost) pure water.
At the anode, two Cl- ions form chlorine gas, and the remaining Na+ ions can migrate to the cathode half-cell because Nafion is permeable to cations.
At the cathode, a H3O+ ion is reduced to a H2 molecule. The remaining OH ion reacts with the Na+ ion to form an NaOH molecule.

If the chloralkali process is done with an asbestos diaphragm, the NaCl electrolyte is used on both sides.

What electrodes do you use?

[Edited on 8-12-2025 by bearbot22]

Hexabromobenzene - 7-12-2025 at 19:18

Anode is steel waste. It dissolves, forming FeCl2. The cathode is made from a stainless steel shower hose; it's flexible and has a large surface area. It surrounds the anode chamber.
I varied the volume of the cathode chamber and made a dilute salt solution to prevent crystallization, but still achieved a yield of about 30%.
The best results were achieved with potassium sulfate; I was able to increase the yield to almost 50%.

Hexabromobenzene - 7-12-2025 at 21:31

I'm having trouble understanding the theoretical yield.
So:
1. We have sodium chloride in one compartment. This means we'll have a yield of x. It will be stable over time since iron ions can't leave the neutral zone, and there's no acid there.
2. Sodium chloride in two compartments. The yield will be 2x, but will drop rapidly due to the twofold depletion of ions in both compartments. The yield will be higher than in the single-chamber case, but it follows a more complex formula.
3. Ion-exchange membrane. The yield will be x, but more complete conversion is likely possible because the ion-exchange membrane is a separate electrolyte. Neutral zone cannot be penetrated into the anode chamber

[Edited on 8-12-2025 by Hexabromobenzene]

Hexabromobenzene - 14-12-2025 at 01:07

I probably understood the mystery of the high yield of hydroxide from potassium sulfate. Solid potassium sulfate crystallizes on the diaphragm and acts as an ion exchange layer. With potassium chloride, the yield of alkali was the same as with sodium chloride
Something similar happened when obtaining acid from sulfate directly in a concentrated solution

Sodium chloride give around 30-35%,potassium chloride around 37-43%, potassium sulfate 45%-50%

[Edited on 14-12-2025 by Hexabromobenzene]

Hexabromobenzene - 1-1-2026 at 20:50

Electrolysis was performed with an improved diaphragm. A non-woven polypropylene diaphragm was wrapped with another layer of fabric. Ion-exchange resin from a water filter was placed between the diaphragm and fabric.

430 grams of salt were dissolved in 3 liters of water and electrolyzed with an aluminum anode in a diaphragm cell with approximately equal volumes of the cathode and anode chambers.
275 ml of NaOH solution with a density of 1.3 was obtained. Approximately 100 grams NaOH. Yield was again one-third.

However, the metal hydroxide precipitate in the anode chamber was significantly lower. By a factor of 5-10.

Conclusion: Ion-exchange resin slows the penetration of alkali into the anode chamber but does not increase the yield. However, when producing sulfuric acid from sodium sulfate, it is necessary. Otherwise, you will get a very low yield.

The high alkali yield from potassium sulfate remains mystery. I believe the reason is the dilute solution.
In a non-flow electrolyzer, sodium salts can be decomposed to approximately 35%, the potassium salt up to 50%.

If you want to get a high yield of acids, then decompose salts of weak or poorly soluble bases.

[Edited on 2-1-2026 by Hexabromobenzene]

Hexabromobenzene - 1-1-2026 at 22:23

Aluminum chloride solution was too dense. I measured its density and got 1.16. The density of the sodium chloride solution for electrolysis is 1.09. 1150 ml of aluminum chloride solution was obtained. This means the conversion is greater than 50%. WTF?

Even if there's still sodium chloride left in the anode chamber (usually very little remains in the anode chamber).

Sodium has disappeared somewhere. It's possible this is because of the ion-exchange resin used, but I'm not sure. I need more experiments; I don't understand.

Hexabromobenzene - 12-1-2026 at 06:02

Electrolysis was performed using a new diaphragm with a layer of ion-exchange resin. The anode was iron. The amount of salt was 700 grams. 465 ml of a solution weighing 600 grams was obtained, and some of the liquid remained in the crystallized salt(up to 50 ml). The sodium hydroxide yield was approximately one-third-34% without remaining in salt. There was noticeably less iron oxide sediment in the anode chamber. In this case, approximately 1420 ml of iron chloride solution with a density of 1.23 was obtained.
If calculate based on ferric chloride, the yield is 57%. Of course, the ferric chloride solution contains salt, but there isn't much of it, and in any case, the yield is too high.

Hexabromobenzene - 12-1-2026 at 07:24

I've reconsidered the theory. The data above is correct, and apparently the degree of sodium chloride decomposition by electrolysis cannot exceed 40%. For potassium salts, the limit is somewhere just over 50%.
A layer of ion-exchange resin only slightly (a couple of percent) increases the current efficiency, but significantly inhibits the mixing of the cathode and anode liquids. This isn't as critical when producing iron salts because iron hydroxide is immediately formed and blocks mixing. But it's very important for producing sulfuric acid, for example.

If you have a huge pool of salt water, like the sea, you can always produce alkali or chlorides in very high yields.
An interesting fact is that even if the salt solution is only in one chamber, degree of sodium chloride decomposition is still one third.

[Edited on 12-1-2026 by Hexabromobenzene]

Hexabromobenzene - 24-1-2026 at 13:28

500 grams of calcium chloride dihydrate were dissolved in water to a volume of 3 liters. Electrolysis was carried out with an aluminum anode. Approximately 6-8 Faradays of current were passed through the solution. 1135 grams of solution with a density of 1.2 were obtained in the anode compartment. In the cathode compartment, a very large amount of a scale-like mass was obtained, which settled on the cathode. I cannot remove the anode chamber without carefully breaking up the precipitate. The initial solution density was 1.1.
If we assume that only aluminum chloride is present in the anode chamber, then the yield is about 75%.
When might a similar synthesis be needed? For obtaining iron salts of carboxylic acids for pyrolysis and obtaining ketones.

Сurrent drops noticeably towards the end of the electrolysis at a voltage of 5 volts from 2.5-3 amperes to 0.7 amperes at the end. To complete the electrolysis, the voltage needs to be increased.

[Edited on 24-1-2026 by Hexabromobenzene]

Hexabromobenzene - 25-1-2026 at 10:31

The alkali yield from potassium chloride will be revised. It is probably the same as from sulfate, about 50%. Additional experiments will be carried out

The photo shows an aluminum anode and a stainless steel shower hose cathode. Convenient flexible cathode, but has high resistance. Several contacts are attached to it, which are immersed in liquid during operation.

Varungh - 7-2-2026 at 06:23

I believe you can make ink from iron clorides. Those sell at a good price. You can try that.
Also any idea in how to obtain AlCl3 in neere anhydrous state? AlCl3(anhydrous) is useful to say the least.
Also AlCl3 hydrates release HCl on heating. Try that.
Use a borosilicate jar, thick. Maybe from those kitchen goods stores

Hexabromobenzene - 7-2-2026 at 08:59

I don't think you can obtain anhydrous aluminum chloride this way.
If you want it anhydrous, first obtain zinc chloride, calcine it, and mix it with aluminum powder.

Initially, I needed alkali, and the metal chlorides were a nice bonus. Then the method was improved. Reducing the anode area and adding a cation exchange resin layer significantly increased the chloride yield.

Hexabromobenzene - 12-2-2026 at 11:46

Apparently, zinc chloride forms a stable anionic complex that sequesters zinc ions. This is good news, as it increases the current efficiency. I achieved 35% salt conversion with only 70% of the theoretical charge. With a cation-exchange membrane, the efficiency would have been close to 100%.
Perhaps aluminum has similar properties.

Also, during electrolysis, a dense deposit builds up on the walls of the anode chamber, but thanks to the addition of a layer of ion-exchange resin between the layers of fabric in the diaphragm, there is virtually no zinc hydroxide deposit that falls to the bottom. Zinc hydroxides are now formed solely by electric current, not by alkali diffusion. Only small amounts of finely dispersed copper from the alloy contaminate the final solution.

Next, I will attempt to make a membrane from ground ion-exchange resin and polyethylene.

[Edited on 12-2-2026 by Hexabromobenzene]