Timeline for Suppressing flammable foam formation in electrolysis
Current License: CC BY-SA 4.0
24 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 16, 2021 at 18:35 | answer | added | Buttonwood | timeline score: 4 | |
| Dec 16, 2021 at 18:24 | comment | added | Jason C | @Martin-マーチン Sorry; I'll clean it all up (including this comment) when I post an answer. | |
| Dec 16, 2021 at 18:20 | comment | added | Martin - マーチン♦ | Comments are not meant for extended discussions, you can use Chemistry Chat for that. Please don't edit the question to include the answer. It is not necessary, and not recommended, to include commentary of how the question changed, the edit history takes care of that. The question should be concise and have the first-time reader in mind. | |
| Dec 16, 2021 at 17:16 | history | edited | Jason C | CC BY-SA 4.0 |
added 188 characters in body
|
| Dec 16, 2021 at 17:12 | comment | added | Jason C | (Also, tbh, the fire hazard is my lesser concern; the main one is the splashing of not-always-nontoxic electrolyte solution if it does ignite, and other resulting physical annoyances; separate containers like you describe can definitely help, and also if I can keep the foam down enough, then splash guards and securely mounted electrodes will mitigate the rest. That little cup in my video isn't my normal setup -- my bigger tank is way less sketchy.) | |
| Dec 16, 2021 at 17:07 | comment | added | Jason C | @Poutnik That's a great point, thank you. That must explain the relative violence of the reaction when I ignited it, and (I didn't mention this above) might also explain why I occasionally have observed a spark at one of the electrodes that doesn't ignite the foam (those sparks must have only caught one of H2 or O2, since they're concentrated around their respective electrodes). I might try a salt bridge setup just for kicks (I've been meaning to mess with that and other membrane setups for a while) but, practically, I'd have to think about how to make it convenient for normal use. | |
| Dec 16, 2021 at 17:01 | comment | added | Jason C | Also, pro-tip: Do not mix mineral oil, simethicone, and water, unless you're prepared to spend the rest of your life cleaning up. Alone, they are weak and helpless, but with their powers combined, they're like the kryptonite of soap. 🤪 | |
| Dec 16, 2021 at 16:57 | comment | added | Jason C | (There's a bunch of commercially available defoamers that are reasonably priced, too, although the ones I really wanted were only available from China in very large quantities e.g. Shin-Etsu KS-540; pH is an issue and there are definitely defoamers specifically designed to be stable at high pH's; it's actually a pretty interesting field. I'm not sure if the baby drops will struggle long term at pH > 9 or not but we'll see; if so I'll try to look for something commercial. The anti-gas drops are very cost-effective and working so far. Sigma-Aldrich has some too but their details are unclear.) | |
| Dec 16, 2021 at 16:53 | comment | added | Jason C | @EdV I ended up doing a ton of research into antifoaming agents. Simethicone is a common choice and the insolubility is the big challenge (validating, heh). Long story short though emulsion-type antifoamers are the go-to for aqueous solutions. Simethicone based ones are usually an emulsion prepared with methods I don't understand that seem to involve stearates, sorbates, and glycerides but ultimately I found some patents that lead to searches that led to .. drum roll .. OTC simethicone infant anti-gas drops. And they are giving very promising results. Details once I can characterize it. | |
| Dec 16, 2021 at 7:24 | comment | added | Poutnik | The easiest partial solution is to have separated anode + cathode compartments ( e.g. using a salt bridge ) to have separated H2 bubbles and O2 bubbles. Pure H2 does not explode, just burns - remember the airship Hindenburg. H2 + O2 mixed in the (near) ideal electrolytic ratio like in your original arrangement would explode magnificently. | |
| Dec 15, 2021 at 21:24 | comment | added | Jason C | Yeah. Actually that was my first attempt (I cook a lot of pasta, I know what's up lol). But for some reason this foam is stubborn and I couldn't find a balance between knocking it down and blowing it all over the place. But if it was a more fragile foam then thatd 100% be my method of choice. I have been tossing some similar physical strategies around in my head though, e.g. air with some sort of overflow trap, etc. If I think of anything that works I'll post it here. | |
| Dec 15, 2021 at 21:21 | comment | added | DrMoishe Pippik | Perhaps just provide a steady stream of air across the surface to an outside vent. This is what is (or was, pre-Li-ion) done where large lead-acid cells are charged, such as aboard ships and in telcos's. | |
| Dec 15, 2021 at 21:18 | comment | added | Jason C | So I put about a 5mm thick layer of mineral oil on top and it's not perfect either but it's surprisingly effective at limiting foam quantity (foam still forms but disappears more quickly). The effectiveness decreased with temperature, and it becomes completely ineffective around 130F or so (although that's way hotter than I normally run at). ... It's a bit messy though, and also I'm wary of putting the electrodes in through an existing oil layer, but with a larger container maybe I can put a circular ring in to act as a caisson of sorts. | |
| Dec 15, 2021 at 21:02 | comment | added | Jason C | en.m.wikipedia.org/wiki/Defoamer gold mine of plan Bs btw. I knew there was a word for this. | |
| Dec 15, 2021 at 20:51 | comment | added | Ed V | Alternate Plan B, if the simethicone fails: a quick short spritz from a can of engine starting diethyl ether (aka engine starter fluid). Reference: early on in Fear and Loathing in Las Vegas by Hunter Stockton Thompson. | |
| Dec 15, 2021 at 20:48 | comment | added | Jason C | Hmm. I ended up adding about 1.5g of it. It does change the characteristics of the foam a bit (larger cells, but not uniformly), somewhat slows the formation rate, and helps it clear significantly faster when the reaction is stopped, but requires frequent agitation and isn't quite there. It tends to ride up the foam, and also behaves very much like an oil on the surface. I'm certain the solubility is the issue. But not calling it a failure yet. Not right this moment, but next try will be to add more of it (enough to cover surface) then I'll try the drinkable stuff after that. Stay tuned. | |
| Dec 15, 2021 at 20:12 | history | edited | Jason C | CC BY-SA 4.0 |
added 59 characters in body
|
| Dec 15, 2021 at 20:10 | comment | added | Jason C | @EdV Simethicone acquired. Internet says it's very insoluble in water but it's also slightly less dense so maybe it'll float on top and do its thing. Fingers crossed. Got softgels; the drinkable stuff is mixed with aluminum and magnesium hydroxides and also has less of the stuff in it. | |
| Dec 15, 2021 at 20:06 | comment | added | Jason C | It's almost certainly got both H2 and O2 cells. | |
| Dec 15, 2021 at 19:51 | comment | added | Maurice | Are you sure the foam is made of $\ce{H2}$ ? In my opinion I would guess it is a mixture $\ce{H2 + O2}$ ? | |
| Dec 15, 2021 at 19:41 | comment | added | Jason C | @EdV Good idea. Simethicone, iirc. Will have to be wary of additives for testing but if it works the lab grade stuff is a little pricey, but not prohibitively expensive (especially if it doesn't take much). | |
| Dec 15, 2021 at 19:38 | comment | added | Ed V | Might try over the counter “anti-gas” stuff sold in drug stores. It is intended for human stomach use, so no disposal issue. If it works to suppress the bubbles, then case closed. | |
| Dec 15, 2021 at 19:21 | history | edited | Jason C | CC BY-SA 4.0 |
edited title
|
| Dec 15, 2021 at 19:14 | history | asked | Jason C | CC BY-SA 4.0 |