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Make Sulfuric Acid (Copper Sulfate Electrochemical Method)
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- Опубліковано 24 гру 2009
- How to make sulfuric acid by electrolysis of copper sulfate using an inert anode. Copper sulfate is very easy to obtain in large quantities at gardening and hardware stores and provides a convenient route to sulfuric acid if the appropriate anode can be obtained.
Warning: This should be done in a well-ventilated area as hydrogen gas build up is explosive. Copper sulfate is toxic and sulfuric acid is corrosive, wear gloves when handling them.
The procedure is extremely simple, just get a copper sulfate solution, insert two electrodes and run a current through them. The anode, the positive electrode, must be an inert material that can withstand extremely oxidizing conditions. Very few materials meet this condition, platinum, lead dioxide, and carbon among them. Other metals, even stainless steel, are quickly destroyed under these conditions and cannot be used. The cathode, the negative electrode, is exposed to reducing conditions so the metal requirements are must less stringent. Copper is the best choice here since it has high electrical conductivity.
When applying power, the current should be adjusted so that corrosion at the positive terminal and bubbling at the negative terminal are both minimized. The bubbling at the negative terminal is hydrogen production and that's wasted energy that should have gone into reducing the copper sulfate.
After the solution has gone clear, filter off the particles and the clear filtrate is dilute sulfuric acid that can be boiled down to obtain concentrated sulfuric acid. It will have trace amounts of metals but for most purposes this is not an issue.
Keep in mind that it will take a long time for the solution to go clear. if after filtering it's still blue, you'll need to keep electrolyzing it. You'll need over 60 amp hours of current per mole of copper sulfate, and usually more since the process is not very efficient.
i switched the carbon electrode for a graphite one and it worked considerably better. the graphite didn't erode and it worked very quickly and very well
Holy crap I didn’t expect to find you here ten years later
@@jasonnikakis6033 second that
As in a lead pencil?
@@dragan3290 I tried pencil lead the same day I commented that, and (possibly due to my power supply being too strong) I just got super fast erosion and heating (some of the tape I used as a quick test for the electrodes melted). I plan on opening alkaline batteries for zinc and manganese so I'll definitely get some proper carbon electrodes from those too
@@jasonnikakis6033 aaaawwww yeah! Alkaline battery? I forgot all about that! I need to do a refresher in electronics! Lol. Thanks for the quick reply 👍👍👍👍
@awsomeman93
If after the warning at the beginning where i say that copper sulfate and sulfuric acid are toxic and corrosive, you still ask if you could drink this then...
Please do.
I don't think gold can be used, but i am working on other methods using cheaper electrodes (other than carbon). I'll post when i find something viable.
@nurdrage I covered my graphite electrode with filter paper (2 layers, wrapped around) and prevented the C particles contaminating the product. Thanks for this video; I've now reclaimed my excess CuSO4 and have smelted the Cu :)
please read the video description
If anyone wonders I just calculated that 750 grams of cupper sulfate pentahydrate should give a theoretical yeld of 161 ml of concentrated sulfuric acid. Just saying...
thank for that i was one of those wondering... and what concentration over 50??
Cool
Do i can use gold electrode and titanium electrode ?
Could you end up with 99% acid if you use anhydrous copper sulphate? It seems that about 1/3rd of the weight of copper sulphate pentahydrate is water and must be almost impossible to achieve a concentrated acid from electrolysis alone. I might actually try it with anhydrous and just keep adding it until no more dissolves and see how much I get.
@@mrdojob Whether you dissolved anhydrous copper (II) sulphate or copper (II) sulphate pentahydrate into water, the copper (II) sulphate will dissociate into the solution. Sadly, it won't make a much of a difference if you dissolved anhydrous copper (II) sulphate instead of copper (II) sulphate pentahydrate. You eventually end up with Cu(+2) and SO4(-2) ions in the water.
gardening and hardware stores have it,
some will sell it by the bag-load (>10kg)
its used to kill roots in drain pipes, and kill algae in ponds.
also used as a fungicide.
@misko112100
because i don't know what's in your particular brand of rootkiller. i'll say no.
I find it's not a good idea to try stuff without knowing what's in them.
@zcuttlefish
as explained in the video, the copper is reduced at the negative alectrode and deposited, the water is split at the positive electrode and oxygen gas is released while H+ ions are left behind to recombine with the sulfate and produce sulfuric acid.
A side-reaction that also occurs is the H+ can also get reduced at the negative electrode to produce hydrogen gas. thus the warning about the hydrogen gas build-up danger.
@misko112100
please watch the video, i made a rather blanket statement as to what i think of other electrodes.
I could be wrong though, but asking me if i'm wrong before i know so kinda doesn't work. I encourage you to do further research or try an experiment.
@jbohbot1
i haven't actually tried it myself with the proper membrane/partitions so i can't really advise how viable it is. I just know it's different.
Love it. It's great to be able to make these acids without having to buy them.
About a year ago I made copper sulfate from Magnesium Sulfate (Epson salts) so it would be nice to say that I could get H2SO4 from something you can get down the local grocery store.
As always, many thanks for pointing me in the right direction.
I hope I never tire of learning new things.
@adigal123 I'll make a video when platinum prices go down enough that i can buy some platinum
You bring up a valid point, I'm trusting the supplier to give me a platinum electrode as described but i don't have an independent test to confirm that is indeed what i received. I'll have to look into this further.
The old ways involved high temperatures. While not too hard most hobbyists prefer not to deal with them.
Check out "lead chamber process" and "contact process" for sulfuric acid production.
Hey, been enjoying your videos for a week now, just wondering if a magnesium electrode could be used to perform the same reaction but from magnesium sulphate? It is slightly cheaper to purchase, but you say other electrodes work terribly, did you just mean for copper sulphate solution specifically, or this reaction in general?
@LucyiX
I haven't tried tungsten, i'm not certain how it will perform. If you should have some and can give a test then let me know your results :)
for any one wondering Lead dioxide anodes can be used , it works just as effectively and doesn't degrade at all.
metallic lead electrodes works good too
+Sir Shad:
You can use lead but the + lead electrode (anode) would get oxidized to PbO2.
I have done electrolysis of H2SO4 with 2 lead electrodes and that's what happens.
Infact i did this by accident once, when i tried copper coating a bullet via electrolysis.
I found that a lead metal strip seems to work pretty well for an anode. The surface just oxidizes to PbO2 and keeps liberating oxygen without corrosion. A cheap alternative if you can't get platinum or don't want to take apart a battery.
Wouldn't it be a better Idea to add the dioxide layer in a separate solution so there's no Lead contaminants in your Acid? I'm not a chemist so correct me if I'm wrong, but it seems logical.
@vaibhav1803
i'm NOT saying don't use it, i'm saying graphite is carbon. the other poster seemed to think graphite wasn't carbon.
Really nice! I tried this one and it worked well - then I simply used a ceramic pot on the stove to boil away most of the water. The problem is as described to find a good electrode for the anode - even carbon rods rapidly get pulverized into particles so fine it's hard to filter out (perhaps easier if using something better than coffee filters). As the water is boiled off - even the dirt gets concentrated and the finished acid will end up rather dirty.
Although the corrosion of the anode does not seem to be affected very much by the current. Of course - for example twice the current cause it to erode away twice as fast. But the conversion from copper sulfate to sulfuric acid also goes at twice the speed (so electrode consumption is not higher). It does however, corrode faster and faster as the process go on - the acid seems to have worse effect on a carbon electrode, than the sulphate. I did put a coffee filter over the electrode during the process - that collected most of the carbon particles and maked the sulotion stay clear enough to watch the process going without the need to stop and filter out carbon residue, all the time.
Same thing seems to apply to the hydrogen production. The amount of energy wasted on hydrogen production is determined by the ratio between copper sulphate left and already reacted acid. There is no hydrogen being produced at start - then it start's bubbling more and more at the cathode as the reaction goes on.
Only thing that happens if you turn down the current once the bubbles start coming is that you slow down the reaction so much that you don't notice the bubbles any more (but the same amount of hydrogen is still produced - just at a slower rate). After a while, it starts bubbling again - and you turn down the current even more. That happened to mee. I was starting at about 5 amps, then gradually dropped down to 1 amp during 12 hours. After that - the sulotion was still slightly blue and some bubbles where coming from the cathode anyway.
Then I turned the current up to about 10 Amps, just to see what happens and there was a lot hydrogen fizzing from the anode, but it went clear in a little over 1 hour - and the electrode didnt corrode faster than it did with 2 amps during 5 hours.
According to my other experiences with electrolyzis as well (I have made hydrogen/oxygen production and iron oxide production) - the speed of the process is directly set by the current. Current density doesn't effect the speed of the reaction - but it do affect the efficiancy and shud be kept as low as possible. Bigger electrode surface area allow for that, and put them closer together decreases resistance. The thing is that the voltage that needs to be applied to get the desired current shud be as low as possible. Every volt above the minimum needed to keep reaction going is just a waste of energy. It doesn't speed up the process - that energy is just turned to heat.
@coplants
you can go further, but hydrogen production increases, so you need to perform this in a well-ventilated area to prevent hydrogen build-up. Other wise use a sealed cell that you can direct the hydrogen and oxygen gases outside and away from your work-area.
@TheCLockMen
Yeah, it certainly would produce more concentrated acid if it evaporated.
but be careful, if you're pumping that much current in you might damage your expensive platinum electrode. Also ventilation is important to prevent hydrogen buildup.
@steq22 yes you can use copper sulfate pentahydrate, no you cannot use stainless steel for the electrodes. it must be platinum, carbon, or manganese dioxide.
@StefanB2112 i got mine off ebay, although i'm trying to see if i can make them.
i tried doing this one with a tungsten electrode and it worked really well.you can buy a rod online but i made mine from a bunch of old lightbolb wires
@Achnavar less current, it'll take longer to work, but it'll be more energy efficient and damage the electrodes less.
@jpthecreaton
You're dissolving off the oxides on the copper.
Try it yourself, get some sulfuric acid, leave a hunk of copper in it, and tightly seal the lid so no air gets in. The copper itself will be unaffected.
@mV33rs
Not all processed carbon is conductive enough for this to work. Carbon meant for non-electrical purposes may be mixed with binders and clay to give it better properties, but it will be less conductive.
Battery carbon is the best.
I got my anode in today, I tried the carbon anode a few weeks ago and it worked.
Got it wired to an atx power supply's 5 volt rail rated for 22 amps and its working nicely.
titanium passivates, and stops conducting, if used as on anode. so it has to be plated with something.
i'm not exactly certain how long a platinum surface will last. i think it depends on many factors like current density and the impurities in the solution.
I hate to ask this but please thumb this up so everybody can see:
A cheap way to make this electrolysis is to use silver solder wire (just make sure it's not thin wire) to replace the platinum electrode. I tried it with a 5 amps current and started with a 50 degrees celsius saturated solution of copper sulfate. I don't know the concentration of my acid but i know it's more than 1 molar since the pH is lower than 0. The results are stunning and my acid is really pure.
there are lots of ways to get ferric oxide, some of them more involved than others. purity and final use determine which way is best. If you wanted some right now just to have as part of a collection then just get some iron rust.
it's a side product, hydrogen is also formed since some of the electrons will reduce the hydrogen ions into hydrogen gas, as well as the copper. Only precision voltage control relative to a reference electrode can prevent this. Very difficult for an amateur to pull-off.
Kinda like microwaving a glass of water and a mug of coffee at the same time. You just want the coffee to heat up but the water is going to heat up anyway. Same thing with copper and hydrogen.
@jpthecreaton
So you DIDN'T do the experiment correctly.
Try the experiment again, this time without the steel. Get a hunk of pure copper metal, then add it to sulfuric acid under air-free conditions, it won't dissolve.
Finaly!!!
It doesnt costs much, can be done by an amateur,and it?s working!!!!!!!!!!!
Very,very,very useful video!!!
Please point out where i said it came from the anode.
@MV33rs
What do you mean "didn't work"? It did absolutely nothing? or did it corrode and shred itself into a million pieces?
@Athiril yeah i consider it a little too dangerous. sulfur trioxide is carcinogenic and difficult to work with.
@electrosphere75
no, the chloride ions will oxidize to chlorine.
@JehuMcSpooran
how would you convert magnesium sulfate into copper sulfate?
1) Separate a solution of magnesium sulfate into two half-cells separated by a salt-bridge
2) Use copper electrodes (it's really only important that the anode is Cu
3) Run a current... The anode half-cell will produce CuSO4 and the cathode side will produce Mg(OH)2
@jpthecreaton
Steel? where did steel come in? i thought we're seeing if pure copper dissolves in acid.
I got 100 ml from 1 pound of copper sulphate
Thank you 😘 NR you are my love
Please make video on nitrc acid from ammonia 😍
@jpthecreaton
Then we have conflicting experiments then. I've left pure copper electrodes in a sulfuric acid solutions for months at a time without any ill effects to the electrodes under oxygen free conditions.
Even in theory copper shouldn't be dissolved by acid (research standard reduction potentials for more information)
Does anybody else have almost no idea what he's talking about, but are watching his video's anyway because they're awesome? Am I the only one?
@Achnavar What's wrong? you didn't read the video description.
@Zink575
I NEVER said that it could be done with MgCl2.
CuCl2 would become copper and chlorine.
nitric acid formation would redissolve any copper.
Aluminum would dissolve, it's too reactive, titanium would passivate as an anode.
@albgk
considering platinum costs more than my computer its going to be a long time before i ever get some :)
If your silver piece is pur silver, it could work. Although im not sure about the plated piece of metal since the plating is rarely perfect. If you dont need a high quality product and if your coating is good, then i think it would be worth to try.
carbon, platinum (and maybe lead dioxide) are the only electrodes i know of that will work. Other electrodes corrode terribly.
@jiraya12345
so you want high purity?
dissolving iron in nitric acid and then pyrolysis of the iron nitrate should yield some extremely pure ferric oxide powder. very expensive though.
i'm definitely going to get around to the sub4science thing.
I just had to do an experiment since i vowed to have 4 experiment videos per month. :)
Aluminum is less easily reduced than water. so instead of aluminum metal depositing at the cathode hydrogen will bubble out.
It's probably really basic electrochemistry but you just blew my mind.
Cool video! I'll have to try it myself when I get the supplies.
Hey for those of you who can't get their hands on Platinum, Use stainless steel. I used a new coat hanger for that. Worked fine, no erosion at all.
@jpthecreaton
Alright, now i see what's happening, the air dissolved in the acid solution is reacting with the copper to make small amounts of copper oxides that dissolve into acid to form copper sulfate which is what plates out onto the steel when you dip it in.
If you did the same experiment under laboratory conditions carefully excluding air it wouldn't work. I should know because I've done it under laboratory conditions without air. ;)
Not with magnesium sulfate,
but i'll try to explore other sulfates like ammonium sulfate.
What's preventing the reverse reaction from happening?
@vevenaneathna
already too many channels making explosives, so i'm not going to.
Lead anode works very well. The oxide layer mostly stays on the electrode and if it falls off, it can be easily filtered off. However, if you don't want the acid to be contaminated with lead you will need to distill it.
@mv33rs
i have a video on obtaining carbon rods from batteries.
Almost all alkaline and carbon-zinc batteries have carbon rods,
rechargeable batteries, and lithium batteries do not.
I tried it like you showed here and it works perfect. I hate the smell of SO2...but im glad that i have my H2SO4.
@adigal123 however much you want, depends on how many electrode you intend to make and their size.
But platinum, especially from a chemical supply company (that sells at an excessive markup) is disgustingly expensive. And doing chemistry for the first time with little experience means you WILL screw up your first dozen or so experiments. Do you really want to risk that much money on it?
thi sis the most intresting channel i hav ever seen
@Zink575
pure lead would corrode into particles of lead dioxide that will get mixed in with the acid, while you can filter it off, dealing with lead waste isn't worth the hassle and it's illegal to dump lead wastes with regular trash.
I'd say don't bother and just get a bunch of carbon rods instead. A lot easier to deal with carbon than neurotoxic lead.
This gave me an idea to use gypsum (reclaimed drywall), CaSO4, to make CuSO4, then make H2SO4 using copper as an intermediary. It may be too slow, but hopefully the low-solubility Ca(2+) would go into solution as needed.
First, in the electrolysis cell, anodize the copper:
CaSO4 + Cu + 2 H2O --> CuSO4 + Ca(OH)2 + H2
Then I suppose heat it to 100 °C to precipitate the Ca(OH)2 and filter it out (so that it doesn't react later with the H2SO4 to make gypsum).
Then plate-out the copper:
CuSO4 + H2O --> H2SO4 + Cu + 1/2 O2
The above 2 reactions overall:
2 H2O --> 4 H(+) + 2 OH(-)
Ca(2+)SO4(2-) + 4 H(+) + 2 OH(-) --> Ca(OH)2 + H2(2+)SO4(2-)
overall: CaSO4 + 3 H2O --> H2SO4 + Ca(OH)2 + H2 + 1/2 O2
Or just use a galvanic cell with magnesium sulfate and an appropriate separator
postimg.cc/gX7QXTRJ
Managed to make 30% sulfuric acid from this method.
Excellent reversal of the previously shown video of creating copper sulphate using electro-chemistry.
Thanks as always and Merry Xmas Nurdrage!
There are two competing reactions at the cathode: reduction of metal ions into the metallic form, and the reduction of water. Electrolysis reactions will prefer the reaction that requires the least amount of energy. Thus, with magnesium requiring 2.38 Volts, yet water only 0.82 Volts, it is clear that you would not plate out any magnesium.
But let's assume that, for some reason, some magnesium actually plated out. Magnesium reacts vigorously with acids back to ionic form, so MgSO4 wouldn't work
Three questions:
1. Can I do this with Zinc Sulfate?
2. Can I just bind together some pencil leads and tape them to a wire and still call it a carbon electrode? Edit: Yes--I tried it and it worked.
3. Could I do the same thing with a nine-volt battery? Edit: Yes--I tried it and it worked. The carbon is not eroding at all :)
***** Thanks!
I personally think a colored solution of copper/manganese sulfate is the best due to the color indication. So an alkali metal anode would trade places with the metal ions in solution... but H+ is more reactive than Li+, so you wouldn't end up with H2SO4 (you would get LiHSO4). And the groups 1-2 metals would react with the water, so that would not work (?). Aluminum... maybe. I do not know, as aluminum can be surprisingly reactive sometimes (as in the cases with gallium and mercury).
Science Hedgehog No.
Imagine if you do plate out the zinc in the zinc sulfate to make sulfuric acid, the surfuric acid would again react with the zinc and you still get zinc sulfate.
In actual practice, the energy required to remove reduce zinc is more than the energy to reduce hydrogen, and even less to reduce copper.
Thats why copper works. Because once you remove the copper ions from the solution, it does not spontaneously dissolve back.
+Szakembőr TV TMIAE:
What would the home chemist use as a membrane? A salt bridge could work. The Zn(2+) would have to migrate across the bridge. You aren't going to have a clean H2SO4 this way.
+Szakembőr TV TMIAE:
Funny enough, I am using wood as a membrane to electrolyse NaCl solution and to have NaOH. I tested it by adding to a CuSO4 solution and got a precipitate, which is likely Cu(OH)2.
The density is of my NaOH solution is 1.05 g /mL. I will probably distill it a little and then use it to make soap.
I've tried this with a lead dioxide anode and works great.
@ignilc
.... there are so many problems with that method compared to this one that i'm going to ask to you to make a video and show us just how feasible it is.
Could you possibly use a Rhodium electrode in place of the platinum?
you can get tungsten at any welding supply store its sold as tig welding electrodes you can get a pack of 6 electrodes for like 40 bucks thats here in the states
Bro can i use graphite electrode instead of carbon one?
I'm accidentally watching this with Brian Eno's Music For Airports and it is A M A Z I N G, seriously try it
What an amazing video. Can hardly wait to try this process. Fantastic job, keep up the great work!
I tried 316L Stainless Steel & it worked really well.
This was complex. All the concepts were just floating over my head and made me feel like I was in la la land.
Wow, one of your best videos yet.
This is a great video of what not to do when plating lol very informative! Thankyou for making it!
Rust? what would you want with that?
@CarbonScience
The short answer: it's not reactive enough,
the long answer can't be fit into the 500 character limit
I got some lead dioxide plates from a rather small lead acid battery, it's incredible how even being a very soft plastiline like paste, the erosion is 0% and it bubbles a lot! I had a supersaturated solution of copper sulfate and it's still work in progress, I added a little more water and it seems to work a bit faster...
@msduckfuck I did it this way in the video rather than the way you described because the whole point of then video was to do it this way. Kinda like when drawing a landscape asking "why don't you draw portraits?".... the point was to specifically draw a landscape.
But by all means go and do your method. I'm still keeping this video up though. I like it because it doesn't require a complicated gas-reaction apparatus. The platinum electrode is actually cheaper comparatively.
Good informations.thank you
hey, these videos are exactly why ive been subscribed to your Chanel.
It seems like making any strong acid takes another, hard to obtain strong acid...
This really is a useful video.
I dont know how i would find/make a platinum electrode.
Oh well, keep up the awesome videos.
You have like the only cool chemistry Chanel on youtube.
I don't know about how exactly to do the catalyst, it was just something I read a long time ago in a "modern mechanix" article. I imagined just using some burned steel wool in a steel tube heated by a flame from outside.
For leadting the SO3, um... not sure. Steel is invulnerable to H2SO4 and so are some (maybe most?) plastics. HDPE works I think. Maybe you could heat and form a fluorescent light tube? Might crack but it could work. You could just try the rubber tube and see I guess.
@zink575
I already answered all of these questions in a previous response.
I have noticed that if you try to obtain sulfuric acid from drain cleaners, it usually Is black. It probably just reacted with something to make a bit of carbon like you said...
makes sense
i used a 1-molar solution of CuSO4 and want to share the information, that up to a certain concentration of acid (about 5%), the Copper in solution reacts back to Copper Sulfate.
I would recommend using a lower molarity
So... You made sulfuric acid from a bit of wire, weed killer, water, a battery, and something you got from taking apart a battery.
Awesome.
Somehow you've made science so much more interesting. and simple. Thanks!
I suggest that it will be really cool if you will make the video about obtaining a pure crystals of peroxomonosulfuric acid!I have made some by myself and should say that it is more useful than any other chemical in the world(except nitric acid and sodium hydroxide) at least for dealing with e-waste!And it is the perfect oxidizer for making advanced propellents!
@hhmm89 no cuz all electrodes are electroplated, which means that they are coated with a specific chemical so that electricity can pass through them.
i am currently trying it with the carbon rods he describes. so far it is working very well at a current of: 3v, 300milli amps. it is also eroding quite slowly too.
Please make a video on how to make a lead dioxide anode! Would be very interesting as there are no videos about this here. Thanks!
Once again, Nurd, those are some awesome looking copper sulfate crystals. Windows wallpaper quality, even.
It took a long time but I got it. I used a lead fishing weight as an anode and it worked great. The solution has a pH of 1 (now i have to boil off the water because it's very diluted)
For current regulation i used a nichrome wire in series with the electrodes and it worked great too (it's not the most power efficient solution but it's simpler than building a regulated current source :P)
ebay has some, but they are horribly expensive for what you get.
There are online sellers, but they only sell to businesses.
i want to make some in an upcoming video. But i can't afford the platinum