Making Sulfuric Acid From Epsom Salt 

This is the kind of content that RU-vid 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.

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.

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!

This is the gentlest way to make sulfuric acid I have seen on RU-vid. 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! 😁

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.

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

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.

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.

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

Your channel theme just gave you another subscriber! I love it

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.

Amazing experimental explanation of Sulfuric acid formation at home. Thanks for sharing.

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

Thank you. You did humanity a kind service with this video. God bless

Great explanation at the end, buddy!

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

Amazing! Informative! Need more vids from you!

i also loved the clay pot idea.... thank you for sharing!

Interesting video and thank you for explaining how these changes happen. Or just that they happen.

I just got some Epsom salt to revive my battery bank and I didn't knew what to do with it. Now I know! Thanks a lot! Exactly what I was looking for! Like number 300.

I really love the video like this, when you can make much great esperiment with nothing of difficult to found

Great video,thanks for the help

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!

Magnesium Sulfate, cheap and available. Great video!

You need more subs You are great !

This is the kind of content we all need

thanks Harry

The water in the anode container is evaporating due to the heat generated by the 24 volts. You dropped it to 15 volts which would help. At 12 volts half of the heat would be generated and your pot would remain wet longer.

I think there is just a simple physical explaination for the lower waterlevel in your diaphragm cell: You've inserted that pot dry into the main chamber, didn't you? If yes, then the dry pottery will have sucked out water quicker from the inside of the cell than from the outer chamber. The inner Cell has lesser content than the outer, so of course the Level sank under it. If you first make the pot comletely wet by diving it in sacrificed water, that schouldn't occur anymore.

9:00 the water level in the pot probably drop because of osmosis, the clay pot is probably acting as a semipermeable membrane which causes osmosis

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.

You can increase the current and/or decrease the voltage by providing larger surface area electrodes. The process will tend to be electrically more efficent when driven at lower voltage.

The level dropping in the anode chamber could possibly be caused by the current flowing from the anode to the cathode, forcing the anode solution through the porous clay pot and into the cathode solution like a pump. When you removed the graphite rods and H2SO4 solution from the anode chamber, you could see that the particulate from the graphite had deposited into the outer corners of the clay pot. That may indicate flow outwards from the center of the pot.

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!

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

Then you can concentrate the sulfuric acid by boiling the water out. After that, set up a borosilicate glass still with condensor at the output into another flask. Heat the dirty H2SO4 to 337C ( 639F ) and watch it condense and drip into the clean flask (slow, and dangerous, but it works).

I read many comments It may be osmosis like many people say, also could be dialysis or more likely electro-dialysis For starting the cell, I think it will be more rapid to add few drops of acid to increase the conductivity of water👍

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

very nice video.

2:38 This erosion can be greatly reduced if you limit the voltage to slightly over what is necessary to do the reaction. This goes for any electrode. Even platinum will erode if you blast it hard enough

For cleaning Mg(OH)2 just submerge the electrode in vinegar and it will dissolve.

This is really damn cool. Don’t need to buy copper sulfate after all, but I’ll still need to visit the garden centre to get myself a fresh clay pot.

I gave this a go the last few days. I dissolved some 10 large spoons of copper sulfate in about 600ml of warm water. It was quite a vivid blue. I used a plastic container. I could not find a unglazed clay pot so I got a glazed ceramic 20cm diameter pink pot from Bunnings (only type they had with no hole). On two opposite sides I sand papered off the glazing both inside and outside. I put the pot in the plastic container with the copper sulfate and added about 2cm of demineralized water. It was more or less the same level inside the pot as in the plastic container. For the cathode I used copper pipe and for the anode 4 graphite rods tied together. Initially I supplied 30V and the current went from 10mA steadily up at a decent rate. I then set the power supply current limit to 1 amp and let it ran for 1 amp for 5 hours or so. There was bubbling from the anode and a bit of copper around the cathode. I then increased the current to 2 amp and it ran for another 10 hour or so. I had to add water to the pot from time to time, and the pot liquid got warm. After the 10 hours at 2 amps (maybe it was longer as this happened over a few days) the copper sulphate was quite clear with only a hint of blue. There was lots of metallic copper visible and I also saw the outside of the pot was generating small bubbles, which did not happen early on. I then decided to stop. After I filtered off the carbon particles from the solution in the pot I was surprised to see it was pale green. Where could this have come from? Contaminents or from the ceramic pot coloring? The 'acid' from the pot reacts energetically with sodium carbonate. The leftover copper sulfate solution also had a reaction for sodium carbonate showing it became acidic but must less energetic than the acid. I weighed the acid and a 100mL was 121gram. As far as I can gather this means my acid is at 30% concentration which is better than I thought I would reach. Any comments will be appreciated.

yes... been looking for something like this.... however, wished you could show the one with gypsum

Thanks

The higher the voltage, the more corrosion on the electrodes. Better would be 5V at 20A. To get around 20A, you need to place the electrodes very very close to each other. 0,3mm should do that.

POSITIVE ANODE IS THE 4 IN THE CLAY POT AND NEGATIVE CATHODE IS THE 1 ON THE OUT. ONLY ADD THE SALT TO THE CATHODE, AND DISTILLED WATER TO THE ANODE.

You should do a video on your homemade stirrer

Excellent

You probably already got an answer since this video is almost two years old now, but it’s entirely possible that the water level keeps lowering due to the porous nature of the clay pot slowly absorbing water (and maybe even the sulfuric acid) over time and since there is less water inside the pot when compared to outside the pot, the water level inside seems to lower more rapidly.

@Free Living Project - yes, osmosis is part of it - electrolysis like this is the same as a lead acid battery - this will heat up the solution - the water will steam out of the acid concentrating the acid over time - so the full answer is osmosis AND evaporation - one last thing to note is that sulfuric acid is a much larger molecule than water so you getting about 1 part lost water to .7-.8 parts gained acid - and on a side note - low constant current is great but voltage is going to push through the initial resistance - we're not charging a batt so the response will be different - in a LA batt as the batt becomes saturated with excess energy the ESR tends to increase - this is typically what drives the finish rate (stage 3 of the charge cycle) - i'm wondering if a high initial voltage and low current until proper conductivity and then flip it - like a constant current at (for this size) maybe 5 - 10 mA (the concern is heat generation as it's wasted energy and can destroy the anodes over time) and interestingly once the process is complete you can continue to juice it as it will evap the water concentrating the acid - take SG readings with PH - note that the electrical and SG readings ARE temp dependant - (talk to a forktruck service company and/or industrial battery service company as they can get you pure lead 1lb sticks - TVH is our supplier)

He deserve 1 million subcribers.Good luck buddy :)

The reason the reason why the level has gone down where the sulfuric acid is being made is because the mixture of sulfuric acid and water is an endothermic reaction meaning that it creates heat. Every time a new molecule of the sulfuric acid is made then it's going to react with the water that's present. that excess heat that's being created is going to cause more water to evaporate out of the solution then would happen on the other side.

This is freakin epic. Excellent job!!

The reason the water is flowing out, is bc there is a higher concentration of salt outside of the flower pot. Its osmotic pressure that is pulling the water out of the pot. Remember water always flows toward the higher concentration of dissolved stuff.

Scrap Science: Here a video idea for you: Make H2SO4 using sulfur and vanadium pentoxide. You could ignite the sulfur in a container (like a candle), an aquarium air pump and tube furnance using some nichrome wire wrapped around a borosilicate glass tube that has has V205 inside the tube. Might need to add some water vapor to the air flow otherwise it will create Oleum.

Osmosis due to the high concentration of MgSO4 in the cathode compartment causes the water level to drop in the anode chamber.

Sulfuric acid is for sale at my local O'reilly's auto parts for $12.99 for 1.5 gallons. Wouldn't waste my time doing the above for that little of money, but, good job Scrap.

To stop the pot from losing water you have to keep the water levels the same, the difference in hydrostatic pressure is why the full pot is losing water/acid to the magnesium hydroxide side. Water at 2 different levels will attempt to balance eachother to the same level, the pot is simply acting as a filter. If the magnesium side is low on water and the pot is high, the water and acid will filter through the pot to the magnesium side (causing acidity there) 2nd. Since you are using electrolsis, you will lose water due to gas off. Normally you lose 2 X the volume of hydrogen vs oxygen, now because on the magnesium side you are losing 1 part hydrogen, (the oh is binding with the magneesium) on acid side you are losing 1 volume of gas, the Oxygen, the H is combining with the sulfate. That said if you use 2 containers with the same volume i.e. i container of 4 liters, and put 1 pot with 2 liters inside i.e. 2L and 2L, when you fill both pots equally to the same levels, you should lose water levels at the same rates as it is 1 for 1. If you have different volumes, 1 will lose the water faster than the other, and because of the hydrostatic pressure imbalance it will carry the acid to the acid into the hydroxide or vica versa.

I wonder if whatever is causing the water level to decrease could be used to increase the purity of the sulphuric acid. My theory is that at least part of the water drop is due to the water getting electrolyzed and losing an oxygen which constitutes a large part of waters mass. If that is the case then that would remove water without affecting the acid leading to a higher purity product.

What concentration did you get in the video do you think?

Water level is decreased due to osmosis , actually reverse osmosis, using energy water travels from low concentration to high concentration of magnesium sulfate, magnesium hydroxide to decrease it's concentration by diluting it

Nice work. I found you can make copper sulfate first from magnesium sulfate by using a copper anode. Even low voltages with a few AA batteries work well. I also wouldn't throw out the magnesium hydroxide or the carbon sludge either. That's most likely graphene you've made there. Very handy for use with super capacitors.

wow thanks for the education my brain is suddenly full of new wonder :)

Hi Harry. According to NileRed, magnesium sulphate is mostly composed of water. So, expect a low yield of very dilute, unconcentrated sulfuric acid solution. This method is simple to implement, but it's not an efficient way of making sulfuric acid. I would not have thought to use a clay pot as a diaphragm. It's a very good idea. However, it's difficult to know the porosity of the material until you use it, which is why I think the water is seeping through to your cathode chamber. Although, I could be wrong.

Can you make a video on making sulphuric acid with a platinum electrode, then testing the boiled down acid with sugar to see if it dehydrates the sugar?

Also acid evaporates much quicker than water. Hence the use of acetic with face masks. Ammonia also has this property

I did a quick search of the comments and didn't se "osmosis", so I'm chiming in: There may be considerable osmotic pressure pushing the water from the anolyte to the catholyte... You could check this theory by seeing if the total volume of the water is remaining roughly constant (minus the H2 and O2 generated) that would imply that the water is migrating from one side of the clay pot to the other, not vanishing or becoming something else.

to get 24 supply you shoud use the blue wire as negative and the yellow wire as poseitive in the atx with out another 12 v supply

What did you use to seal the drain hole in the bottom of the pot? Love your channel!! 👍

I’m trying to use an acid equilibrium expression to reproduce this same process at the moment, but haven’t got there yet.

i think the water evaporates, it has to do with conductivity and carbon electrode, after the current increases to a point then for some reason it drops again but the electrodes are somehow still trying to pass that current and they get hot, that's why higher voltages are better than higher amps. the osmosis is also at play here though.

10:40 solution... or just rise the water level outside of the pot so that the positive pressure will prevent the leak outside from the pot .

Reminds me of the old Amonia Fountain

@scrap science can you please measure to check if there's any electric current? I guess that you've created a good battery

Is there a way to optimize this setup for magnesium hydroxide creation in higher quantities?

Hi Mate, just found your channel. Its awesome. Explanation drawings are really good, and i like the fact you just use stuff from around the house. Love the stir bar 🤣🤣🤣 Can Magnesium metal be made from Epsom salts ? 🤔 And can Nitrates be made at home ? Just starting out with this interest as you may realise... Thanks.

Sir , what if i use a stainless steel glass instead of clay pots ? here is my plan: > I make a concentrated (NH4)2SO4 solution. > I pour some on a big dish a little amount on it. > Then I place my steel glasses on the dish. > I am adding separate anode & cathode inside of those glasses and are completely separate from the glasses and they arent connected directly. > If I connect it i should have H2SO4 at Anode glass and NH4OH at cathode glass . > Rather than the H2SO4 and NH4OH reacting with the glasses i should have any problem. But my question is in each glasses there will be NH4+ , H+, OH-, SO4(2-) present. Suppose if in the Anode, the SO4(2-) becomes H2SO4 buy gaining 2 protons. But then there will be NH4+ and OH- left at a proportional rate and create NH4OH by reacting. Then the NH4OH and H2SO4 will react and it will be changed to Ammonum Sulphate again? So is it pointless? why isn't the same problem happen with your solution? instead of NH4OH you will have Mg(OH)2.

I wonder if its osmosis that made water lower

I think the water empties out of the pot as water is broken into hydrogen and oxygen. The outside volume is much larger so the level goes down slowly. The pot volume is small and so the level goes down quickly.

So is the ANODE that's in the clay pot is that on the positive wire ?

Wow cool!

do u have a video of making the magnetic stirrer

To my understanding, while oxidation DOES occur at the anode, this reaction produces oxygen at the cathode. therefore, you must still use an inert metal (like lead dioxide). Graphite works, although the reaction of oxygen disintegrates graphite

Recently we had somebody accused for murder attempt in Greece by attacking her victim with sulfuric acid.The victim suffered very much damage.Your video is a fine example of electrolisis but it is terrifing how easily someone with basic chemistry knowledge from highschool can produce such a deadly ingridient.

15% H2SO4 costs 3€90 per litre in the French supermarket. So about the equivalent of 25€ per litre concentrated.

Does the carbon rod will be eated and degraded by the electricity??? Or it will remain the same after that??? If yes, what cai use instead of them???

Not sure why exactly but it worked with a terracotta pot with a hole in the base... I did plug it but after a while it fell apart .. my only guess as to why it continued to work was that I had also placed it on a terracotta dish and I think when it dissolved it was crammed into the gap at the base of the pot forced it to seal? Dunno but I succeeded works on sugar aswell so I think it got it right .. shall give my anodising a try and see what I get 😊 thanks mate

I actually tried this, I used a nickel electroplated copper sheet as the cathode and platinized titanium as the anode ( I got it on Amazon for $45, I thought it was fake until I did the peroxide test and it turned out to be actual platinum.) with a ceramic plant pot as a diaphragm. I managed to get a much better yield. The current was going from 290 milliamperes to 3 amps in 30 minutes. The only problem I had was thick coatings of magnesium hydroxide on the cathode but it was really easy to get off with a stainless steel scrubber. Overall, I am pretty happy with the results. I’m going to do a titration to figure out the concentration

I posted this comment on another video - but here goes. The most likely cause of the migration of water is osmosis. Water molecules move from high concentration of water (the clay pot) to lower concentration - the salt solution. Confirmed by increase of volume in the cathode chamber as the magnesium sulphate solution is diluted. The large difference in volume of the two chambers means the volume increase of the magnesium solution is less obvious in this video.

Nice.

Very nice, thank-you for sharing your ingenuity. I agree with other comments about the osmosis of water from the anode chamber to dilute the salt in the cathode chamber. Happy days!

Can you please show us the making of Sulfuric Acid from Gypsum by electrolysis with non-lead electrodes ?

Is the water level actually running over into The large container or is the clay pot absorbing the water ?

Just wondering: Can a dishwashing sponge act as a membrane for most of electrolysis processes?

Hydrogen peroxide will oxidize and remove the the unfiltered carbon sludge.

I forgot to mention in my comment below that my total volume of acid yield after filtering was around 200mL.

Excellent video, what do you think of using sodium sulfate (Glauber's salt)? We obtain sodium hydroxide and sulfuric acid

how did you seal the bottom of the clay pot? The ones that I've found have a tiny hole in bottom from the manufacturer.

just to clarify, did you omly put water in the anode chamber?