Scrap Science - 2019-03-09
Once again, I make an attempt at the electrochemical splitting of a sulfate salt in a diaphragm electrolysis cell in order to generate sulfuric acid on the anode. In this experiment, I scale up the process to make a larger quantity of acid, ending up with over 100mL of approximately 1mol/L sulfuric acid. From the price of ammonium sulfate fertiliser here in Australia ($10/5kg), production of sulfuric acid by this method, assuming 100% conversion, would cost approximately $5 per litre (if it were concentrated to 98%), not inculding the cost of electricity, distillation, or replacement of the carbon anode (a platinum anode could be substituted however). My previous attempt at making sulfuric acid from epsom salt: https://youtu.be/6BThiJpbBJQ Link to the sulfuric acid from coppper sulfate video: https://youtu.be/ZRYtAquxffE Link to the video where I made the power supply: https://youtu.be/ygvbdwl-0bM Link to the video making the carbon electrodes: https://youtu.be/KKCksH5m7s4
More electrolytes on the outer side wants to dilute. It pulls water to dilute. Similar to osmosis water flows to the side with more salts. Water drops on the dilute side and rises on the salty side unless it is in balance.
I just found this channel, Well done you just earned another subscriber :) Keep up the good content!
Thanks, great to see you here. I'm a fan of your videos and only just realised that I wasn't subscribed, but that's changed now. You've got some really interesting content.
@Scrap Science Wow, Thanks! Wish i found your channel earlier. You also have some great science content
Brillliant!
why you use cley pot🙂
Salt bridge also work🙂
plese make hno3 from kno3
Yes, a salt bridge will definitely work as well, however, a clay pot can handle much more current than a simple salt bridge, making it better for large scale reactions like this one.
Making HNO3 from KNO3 is a plan for a future video, though it will be a long while away as nitrates are illegal to buy here in Australia, so I'll need to obtain the nitrates from nitrogen rich soil and chicken manure, but it will be uploaded eventually.
thank you very much😉
you can get some grams of kno3 from match head ☺️it is essey
@Scrap Science There are a small number of videos on YouTube (e.g. Cody's Lab) showing how to make dilute HNO3 from oxidization of air using electric arcs, but it would be cool to make it some other way without purchasing nitrates like you're suggesting. Maybe burning ammonia vapor?
That's gonna stink like a dirty toilet.
Online, ammonia sulfate costs about 5x as much as magnesium sulfate epsom salt. Also, it might smell horrible like ammonia sulfide.
Although 1 mol isn't too concentrated, this is still a fun way to play around, esp since required items are readily avail and inexpensive.
Where did you get your carbon rods from?
I ended up buying some welding carbons on ebay and removed their copper coating in another video. Removing the carbon rods from zinc carbon batteries also works quite well.
when we add H2O to boiling solution of AlSO4 (alum) then we get
AlSO4 + H2O --------> Al(OH) + H2SO4
but Al(OH) reacts with H2SO4 and we get
Al(OH) + H2SO4 -------> AlSO4 + H2O
any Idea how can we separate Al(OH) and H2SO4 ? and get the H2SO4 out before it reacts
Hope u help.
Thanks
You won't be able to do it that way, try electrolysis
I saw patents they done the same with gypsum. But to incrase effecency they washed around the Anodes SO2 Gas. The Atomic Oxigen there oxydize it to SO3 …..
Since I posted my osmosis comment below I did some more reading. As sulphuric acid in the pot becomes more concentrated it may actually draw some water back into the clay pot, especially as the ammonium hydroxide precipitates out in the cathode chamber. On the other hand this change in volumes might be too small to observe, or the sulphuric acid might not become concentrated enough to attract water back. (" I am a firm believer, that without speculation there is no good and original observation," Johannes Kepler)
Ammonium Hydroxide won't precipitate out. Ammonium Hydroxide is not a stable substance you can isolate. It is a notional name for a solution of ammonia gas in water, of which, a very small proportion will be ionised (ammonium and hydroxide ions) in the absence of any counter anion. Ammonia gas will be emited over time as the catholyte solution becomes more basic.
gazzarrr666 then it precipitates UP!
Can stainless steel be used in place of clay pot?
No. You need something that ions can pass trough
@wwwelkam a bit late there mate... already fixed it all found a video where you can use cardboard or paper... your response is still useless doesn't tell me what ai can use in place of clay lmao
@malcolm cliff Sorry for watching this video too late and not instantly you asked your question. Also that answers is not only for you but for other people as well.
A cardboard has chemicals that will contaminate your acid if used in cell. You need something that is resistant to both acid and base
@wwwelkam well worked for me... thanks anyway👍
Hi. Can I use a lead dioxide anode as I do with the copper sulphate method? Ammonium sulphate is under £20 for 25kg bag in the UK
I would definitely avoid lead dioxide entirely, especially if it was originally made from a lead rod. If the fertiliser is anything less than 100% pure (which all fertilisers are) then you'll end up generating a small amount of soluble lead salts in your product, which is definitely something to avoid if you don't have the equipment and expertise to deal with it.
The only reason I'd use a lead dioxide anode is if the starting material is lab grade, distilled water is used, and the diaphragm hadn't ever been used before. Even then, I'd stick with professionally made titanium substrate anodes rather than an anode made directly from lead metal.
hi , i used 12 volt battery . i used lead anode and copper cathode . the battery cathode become too hot makes the wire almost melting . and i used pc power supply but also it was broken down ?
Dont use the lead anode
Wouldn't it be easier to use a salt bridge between the two solutions by using a filter paper dipped in the solute?
That way you'll have purer sulfuric acid and almost no contaminants?!
I'd used the above for a common salt solution and got pure sodium hydroxide in the cathode and chlorine water in the anode maybe you you could apply that in a future video!
Yep, that’d certainly work to generate a purer product, however, the point of the clay pot is to carry much more current so that a much higher concentration of sulfuric acid can be achieved in a shorter time.
Paper towel salt bridges tend to increase the resistance of the cell so much that the production of whatever you’re making is unreasonably slow. I’ve just found that clay pots are quicker and easier.
If you use a filter paper or pretty much anything that's organic as a salt Bridge then it will dissolve in the anode chamber as h2so4 is formed and it will turn Brown and impure that's why I believe this method with the terracotta pot to my knowledge is the best way👏👏scrap science
Also when using two jars and a salt Bridge the water level still goes down in the anode chamber below the level of the cathode chamber🤔
did you cover the botom of the clay pot with something or doesnt it mater it has a hole in the bottom?
I filled the hole with some silicone sealant, plugging it with a rubber stopper should also work I reckon.
@Scrap Science thanks for the awnser man
Can we use a less volt battery
I wouldn’t use a battery, given they will quickly discharge, but yes, a lower voltage will work, albeit more slowly.
Can you move the anode and cathode electrodes further apart to decrease the amp draw? It looked as if the tips were very close together.
You could, but the reaction rate is directly determined by the current, so a high amperage is favourable if you want to make the greatest quantity of acid in a short period of time.
@Scrap Science Thank you. I was thinking of ways to regulate the reaction if, say, it got too fast or you wanted to let it run overnight.
what does 2 molar solution even mean??
'2 molar' is really just a measure of concentration. It tells you how much sulfuric acid you've actually got per litre of water.
For sulphuric acid, 96% concentration is about 18 molar.
It is literally the number of moles of material per liter, where a mole is Avagadro's number of 6.023 x 10^23 molecules. I seem to have learned that fairly well 40 years ago!
how is the concentration of finish solution? maybe u can sell that
Valentino Zaffrani 18 molar is 96% sulfuric acid, so 2 molar about 1/9, or around 11% in my head.
Fail! That quote was Charles Darwin - not Kepler.
Have you done any further research into why the water transfers from the diaphragm to the outer chamber during the reaction?
Osmosis.
@Elektro Bear What is osmosis?
@ur mum gay how old are you? All your questions are retarded AF
@elyes grati What do you expect from someone with the username "ur mum gay"
Also how does the electrons or whatever travel through a solid object lmao? Sorry i am new to this stuff.
It's not actually the electrons that move through the water/pot, while they do carry charge in the wires, its actually dissolved ions which carry current through the aqueous solution. The clay pot also acts as a porous membrane in this case, rather than being a completely solid object, so that the ions are free to pass through it.
Someone didn't go to school very often to ask a question like that.
Really, you don't know why the water is being pulled from one side to the other? Very simple mechanics at work here, mate. I could tell you and maybe I will later on just what's happening with the water displacement. Also, this in my opinion is the wrong system for this type of work. A better chose would have been Two tanks with a membrane in between the two to separate the two fluids just like what's done to make Hydrogen Gas. This is not the only way to do this. I'll finish watching your video before finishing my comment. Well I want you all that's happening because you need to learn what, why, and how's. There is an Electromagnet working here and water that contains metals. Do you get where I'm going with this? Study up. Just my opinion and it really counts for nothing young man. Thank you for the upload.
@elyes grati Okay. Talking to the wrong person. Sorry mate.
membranes are expensive
this clay pot is essentially a ghetto membrane that will do the job rather than spending on some NaFion sheets
ive tried other membranes including concrete where instead of water i used a salt solution to impregnate it while curing which seemed to work better than a porous pot.
overall this method works nicely for dillute solutions but is inneficient for producing highly concentrated solutions.
edit: if you get your hands on nafion though then YES u can get concentrated acid with all your worries washed away!! except MEMBRANE FOULING!!#!$E23we g j54qujh
u need pure starting materials free of any organic GUNK or it will get fked hard and damage the membrane
@MysteriusBhoice can you provide more information on your concrete method? How was your cell built? And how was the membrane implemented
@MysteriusBhoice Thank you for your advice mate. (I Appreciate your time in responding back to me). Weak Acid is really no problem because you could just boil off excess Water for a more concentrate form. As long as you keep the Acid weak, maybe you could use Plastic or Carbon Felt instead. Maybe a very good grade of Filter Paper may work also. What do you think? Chemours' Nafion™ 117 membraneshttps://www.fuelcellsetc.com/store/N117 ARE 37 DOLLARS A ROLL JUST IN CASE YOU WANT TO BUY A ROLL
@elyes grati to make the "concrete membrane" first get a 50/50 by weight sand and concrete mix
the sand must be a very fine powder so grind it in a cofee grinder.
then add a fine powder gypsum to your mix in quarter of the weight of the total mix.
that will bring the concrete to other material as an ideal 1:3 ratio.
The cell I use is a large clear rectangle box from daiso but you can also use one of those rectangle cereal holders.
you now then have to measure the walls and create 2 membranes to divide the cell into 3 parts.
The membranes are casted and left to cure for a week.
The membranes are then secured using silicone rubber and ensure that its water tight on the sides.
You will only notice if at all a slight dampness on the other side after 10 minutes if at all.
The water level before running is marked and the cell is left running until a drastic increase in water level is seen along with a slow change in current.
Then you must remove the anolyte and get rid of the acid.
if your starting salt is sodium sulfate then you use your refrigerator because all sodium sulfate precipitates below 10 celsius.
If your starting salt is ammonium sulfate then you can run the cell as long as possible!!
if you use magnesium sulfate then you can remove the precipitated magnesium hydroxide so you can keep running the cell.
Dale Smith - 2019-03-09
I enjoy watching your work. Just a comment on your water loss from the anode chamber - good old garden variety osmosis. Water is moving from highest concentration in the pot to lower concentration in the salt rich cathode chamber. The only way to stop that would be to have an equimolar compound in the anode chamber. Would need to be non-ionic and also not react with sulphuric acid. That would also prevent dilution of the salt in the cathodic chamber over time. Good luck with that - I can't think of any water soluble compound that will not react with sulphuric acid in the anode chamber.
Scrap Science - 2019-03-09
Interesting, thanks for the info. Having the water level drop isn't too much of a hassle anyway, seeing as it can just be topped up at the end. I was under the impression that it would be some electrolytic effect or something, this makes much more sense.