Making Sulfuric Acid From Epsom Salt

Electrochemically splitting magnesium sulfate into sulfuric acid and magnesium hydroxide using an electrolytic diaphragm cell. This is similar to a previous video I made where I made sulfuric acid from copper sulfate, though using a sulfate salt where the cation has a lower reduction potential than hydrogen makes the process a bit more difficult.
Based on the fact that epsom salt is around $10/kg for me (AUD), theoretically the H2SO4 generated by this method would cost about $22.50/litre (if it were concentrated to 98%), much cheaper than most sulfuric acid sources.

[noahswindler]

This is the kind of content that YouTube needs more of. Informative, to the point, accurate. I've always thought sulfuric acid could be synthesized by the electrolysis of magnesium sulphate but I could never get it to work. Using a clay pot as an ion channel is damned genius. Thank you for taking the time to make this.

[FreeLivingProject]

The water leaves the clay pot over time due to osmosis. You have a concentrated salt solution outside the pot and water will diffuse from a low concentration solution into the higher concentration solution over time.

[AvianYuen]

This is the gentlest way to make sulfuric acid I have seen on YouTube. The flower pot diaphragm also makes this the most accessible. And the fact that you made most of your equipment yourself... super impressive. Big, BIG thumbs up! 😁

[FulminatodePrata]

Man, i can't even remember how hard i looked for a way to make electrolylis processesses like this one viable, and the membrane part aways failed miserably, or wasn't ideal on my attempts... A flower pot as a diaphragm? That's straight up genius! I hope you get the appreciation you deserve, keep up with your quality content!

[nomorecookiesuser]

I am very glad that this video is available and not censored/buried. Thank you for showing this process in a way that is accessible to us DIY science experimentors. Kudos to you! i will gladly be sharing your channel with others i know, that share the same interests.

[Jawst]

I'm no scientist but as a gardener, I can tell you that the pot needs to be soaked overnight because they absorb a huge amount of water!

[indigopursue]

His setup looks wild!! Even though he knows what he’s doing

[bigchungo]

This is exactly the video I was looking for. Chemistry that anybody can do with stuff you can easily get.

[RoySATX]

I see that others are impressed with the flower pot, and indeed it's a clever solution solution. However, the poor-man's bench power supply in a shoebox is beautiful, a truly moving work of hillbilly art, I am tearing up over how moved I am. The only thing missing, possibly, is a DIY volt meter made from a straw, soda bottle cap, magnet and some copper wire, all of which are easily sourced from along most roadways as you no doubt already know, though that sort of complexity would defeat the elegance of your simple design that I found so moving. Hats off to you, Sir, and thanks for sharing. Normally round these parts this sort of intelligence is kept within the family.

[marcush]

I have not watched this yet. But it immediately peaked my interest because I'm a professional brewer and H2SO4 is a beer off flavor... but we also know what conditions increase its production.

I know fermentation isnt likely useful here due to how small of an amount makes an overpowering egg smell... but it's still cool to see chemicals that I TECHNICALLY create as byproducts being made purposefully.

[petermarsh]

Dear Forum, I thought that it was time to add my penny’s worth to the debate. The change in fluid levels between the clay pot and the surrounding bath is likely due to one of two actions.
1) Oxidation / reduction happening at the Anode / Cathode respectively at the same rate, because they are electrically connected. The smaller volume of liquid in the clay pot is exposed to a greater concentration rate of oxidation. 2M of hydrogen is given off from the Mg bath while 1M Oxygen is given off from he clay pot. Because the clay pot volume is smaller, the level drop rate is greater.

2) Osmosis has also been proposed as a cause of the level changes. The supposition is that the wall of the clay pot is an osmotic membrane. This means that small molecules can pass across it {eg H2O} but bigger molecules like MgSO4 and charged particles like Mg++ and SO4- - cannot. It is affected by a pressure gradient which slows down osmotic transfer. Engineers have taken advantage of the opposite effect in building RO desalination plants. The pressure gradient in this case because of the differential fluid levels would work from Cathode side to the Anode side, the opposite of what is being observed.

Therefore, osmosis is less likely than a differential change due to electrolysis converting solvent into gas where differential volumes are involved.

[pradeeppaul]

Water level in the clay chamber dropped in the beginning, probably due to the absorption of water into the dry clay. Clay tend to absorb water faster than the salt solution on the outer side. If the clay chamber is soaked in water before the experiment, it may not happen.

[deathkeys]

On a note: this is actually amazing, I thought of something similar, but none of my teachers said it could be done, some going as far as saying I would need to own a power plant to simply MAKE ELETROLYSIS! [for those willing to criticize the US educational system, sorry, this wasn't in the US) and yet, here you are, using the most cheaply available materials to make sulfuric acid... ohh the irony... as somebody who also loves to explore science, I truly commend your efforts and feats to this point, also I wish you success and prosperity in your future endeavours!

[harrisonmundschutz]

I think the water was pulled out of the pot through osmotic pressure because there was a higher concentration of salt on the outside

[donaldhoot]

Great video! Something that's ACTUALLY done by a home experimenter! There's too many "safety" guys in the world and this is very refreshing!

[HolyDiver]

I think your pot water level was reducing because in the process of making the o2, 2h20 consumed to form 2h2->4h+ + o2. So first converts to HSO4 then to H2SO4. This is consuming twice as many water molecules as the conversion to Mg(OH)2 you only need 2mol h2o for that vs 4 mol for H2SO4 plus autoevaporation of water

[CatboyChemicalSociety]

magnesium sulfate is probably better than using calcium sulfate
I made a similar video using calcium sulfate and sodium hydroxide/sodium sulfate on the cathode side and had issues with the reaction being uneven and slow.
The reason why this process isnt done often in industry would be because of cost, maintenance and low efficiency.
but in a home experiment scale its really convinient if you cant get your hands on sulfuric acid.
However one thing to note is that as the concentration of your acid goes up it will eventually require more current flowing through the cell to keep the 2 products from reacting via the porous pot.
This can be solved by using a membrane but well you know those aint cheap and membrane fouling can occur due to the precipitation of magnesium hydroixide.
The best way is to run it for a certain time and concentrate the acid to precipitate any remaining salts in the anode compartment and feed it back for another run.
using alkaline sulfates are much more efficient than alkali sulfates because you do not get the formation of partially neutralized salts which can ruin efficiency.
NaHSO4 is a pain!!!

This is about as far as I went with that project but more cane be done such as the best time to swap the anolyte

[hanleypc]

Re: your water levels, looking at this setup with a thermal imaging camera the anode pot is allot hotter than the cathode chamber. Guessing it is causing faster evaporation.

[johnsanchez]

Regarding the water level drop, I would say it is simply being driven by the concentration gradient present between the two solutions. Great video dude

[jaideepmahapatra]

This is the kind of content we all need