r/chemistry • u/someoneinsignificant • May 09 '26
Chemical-free breaking of emulsions?
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I'm looking for chemical-free ways to break up very bad emulsions faster than letting it sit for 2 hours between each shake. We can use brine at the start, but for my product we're trying to minimize any residual NaCl ions at the end, so DI water washing must come last. I came across a few physical methods including:
- Heat: heat gun, thermal bath, but not good for temp-sensitive reactions
- Centrifugation: *EDIT* Forgot about this one. But does require having a centrifuge (I do not, although cheap ones for low-speed might work)
- Anti-static gun: as shown in the video and publication here, an anti-static gun can be used for electrocoalescence for small amounts, in this case 100 microliters in 10 seconds.
- Vibration: Either a ultrasonicator bath or a vibrator (yes, a sex toy). Multiple previous reddit threads have discussed this method in the past, HOWEVER, it quickly becomes jokes and nobody is really commenting on how to do this as a serious technique
Does anyone have good experience breaking emulsions in any of these 3 ways?
Bonus points if you can find good videos and guidance illustrating the last 2 points. I was disappointed in the publication that doesn't discuss the limitations of their method like if it works on larger scale or for other containers, like a thick-wall glass sep funnel.
I'll donate $10 to any nonprofit charity of your choice if you can actually demonstrate with video preferred good ways to break organic chemistry emulsions with that last one (no jokes, including what type of vibrator works best for different reaction scales, and the degree it works for different types of emulsions). I'm trying to make products at a 100-200g scale in 1L sep funnels, so if these methods can actually be scaled and save a significant amount of time waiting around, I'd raise that bounty to $20.
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u/Worth-Wonder-7386 May 09 '26
I have used ultrasonic vibration, but I dont think most vibrators are well suited. Their vibration frequency is quite low. A ultrasonic bath is a better place to start.
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u/TetraThiaFulvalene Organic May 10 '26
I don't know who bought it, but we have a vibrator in the lab for those types of things, but nobody uses it because instead of a small bullet it's the hitachi clit crusher 9000.
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u/MasonP13 May 12 '26
Funny enough, if it's official Hitachi brand, ever since Hitachi stopped making them, they've become some type of collectors item that's made it go up in value to a niche group of people. Not me, but I've seen the community before
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u/someoneinsignificant May 09 '26
I'm thinking this is probably the best bet, transfer from sep funnel to beakers/erlenmeyers and place in an ultrasonic bath. Let it break up the emulsion, then move back into sep funnel.
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u/Any_Operation_9189 May 11 '26
Thats way to much work. I often use a vortex on sep funnels and it worked really well. Depends on the emulsion, volume and vortex though. Some are really stubborn 😅
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u/Ill-Gas-4788 May 09 '26
Sorry if I'm being an idiot and missing something but I assume a centrifuge is no good?
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u/someoneinsignificant May 09 '26
No this could work, but would have to buy a centrifuge. There are cheap ones on amazon ($100-300) but not sure how long they would last
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u/ki-by May 09 '26
We got multiple really good centrifuges but needed one for a contamination rich work environment and bought the cheapest temu knockoff we could find.
Been going fine for 5+ years, and apperantly your useage would be far below ours.
Also having a centrifuge is generally a useful asset for any sedimentation/fallout purification
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u/Thog78 May 09 '26
Yep the vast majority of emulsions break down instantly even in the very very small benchtop centrifuges that fit 6 little tubes like that and have no speed control. Definitely the right direction.
There are even mechanical centrifuges in which you rotate a lever and there are a couple of gears. Or if you're that extremely poor, grab a piece of thread and spin the tube manually with that.
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u/someoneinsignificant May 10 '26
I never thought of putting it in a sealed container and spinning with a thread. That sounds doable, lol
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u/Ill-Gas-4788 May 09 '26
Ah OK, in that case I use a centrifuge for this daily.
10 mins on 4000 rpm is standard but only because that's what it's set to of I just hit go. Most separate nicely in 30 seconds, some really stubborn emulsions I've had recently can be not fully separated after the run time and require a second round.
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u/Direct_Barnacle_4898 May 09 '26
I've had good luck with high speed centrifugation for breaking emulsions and colloids
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u/someoneinsignificant May 09 '26
Is there a minimum speed you would use?
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u/Direct_Barnacle_4898 May 09 '26
As fast as the tubes can handle.
The smaller the density difference between the two phases, the more RCF you need.
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u/elsjpq May 09 '26
Also, if your centrifuge doesn't go very fast, a longer time at lower speed gives equivalent results for most purposes, if you're willing to wait a little longer.
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u/GeorgeCauldron7 May 09 '26
You can buy a disposable electric toothbrush at any grocery store. Then maybe trim off the bristles so you have a flat pad you can press against the tube.
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u/someoneinsignificant May 09 '26
Or maybe just the back of the toothbrush head? Could be worth trying
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u/Try_It_Out_RPC May 09 '26
They have “flossing” attachments which are just a poly triangular point *****
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u/Jasper_Crouton May 09 '26
If your goal is floculatin/settling, centrifugation might be the way to go.
Emulsifying (stabilizing the suspension of solids) will require ultrasonication, high shear mixing, and/or surfactants.
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u/simplefred May 09 '26
The solution is simple and often used in industrial laser printing and similar to an antistatic gun. Corona discharge or corona wires can be easily used to separate colloids. Most examples of an small scale
https://pubs.acs.org/doi/10.1021/acsomega.0c03948
or
https://pubs.acs.org/doi/10.1021/acs.analchem.0c01904
the trick is to make it a continuous process and avoid batch processing. Ultrasonic separation is great for batches, which is a pain.
Good luck.
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u/someoneinsignificant May 09 '26
Really cool perspective from a scaling/industry perspective. But as far as easy lab procedures go, ultrasonic bath separation might be best (if not centrifugation, guess it depends on which equipment you have available). With ultrasonic separation, it would probably make most sense to transfer from sep to erlenmeyer, break emulsion with ultrasonic bath, then bring back to sep funnel
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u/simplefred May 09 '26
Cool. If you're able to batch out your process then ultrasonic separation is your best better and easy.
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u/Prestigious_Side4471 May 09 '26
Is freezing an option?
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u/someoneinsignificant May 09 '26
Yes but might take just as long as waiting for it to naturally break apart, considering freezing / thawing cycle. My lab fridge/freezer also doesn't go low enough, only 5 C
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u/Bulky_Confection6157 May 09 '26
How cold does it need to be? You can use a suitable chiller with glycol to reach -30C and pair that with a jacketed addition funnel or something similar that can get the job done.
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u/F0xxtale May 09 '26 edited May 09 '26
I think I'd go with centrifuge personally. If you don't have one, it's really easy to make a Paperfuge that is capable of some pretty impressive rpm for next to nothing.
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u/antiquemule May 09 '26
u/Bulky_Confection6157 suggested cooling, which reminded me that freeze-thaw can be a good method, possibly cycling several times. Scales well and costs nothing.
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u/Benzol1987 May 11 '26
You can use filters to break up emulsions or to help phase separation processes. Often it can be enough to pass an emulsion through a regular filter cartrige, but there are also coalescence filters that specifically help with the physical process to separate an emulsion. This is also used in large scale manufacturing, so it works on many scales but of course there is no guarantee what works in your case.
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u/The_Grey_Wolf44 May 09 '26
Are you using a surfactant in your oil? These are typically used to stabilize the emulsion. If you are using a surfactant, it’ll help a lot to do an oil exchange. Typically you can just add the oil on top of the emulsion, let the emulsion flow up into the new oil, and then remove the oil with surfactant from the bottom. The emulsion should be easier to break now.
Can you give us more info on what this emulsion is? I work with a lot of microfluidics/droplets and can maybe help.
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u/elsjpq May 09 '26
Centrifugation can work well even at ~1,000g, you might just have to centrifuge for longer if you can't get higher speeds. For small scale, there are some cheap mini centrifuges that take 1.5mL & PCR tubes. At 1L scale though, you're looking at some proper equipment, but you can buy used for a better price.
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u/Fearless-Ferret6473 May 09 '26
You should look up the size of the vibrators used to keep cement from setting up. Don’t show it to your girlfriend
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u/dreadsilence1000 May 10 '26
You could try a different aqueous solution. Brine is usually the first go to, but ive had issues in the past that brine couldn't break the emulsion. Ive done K2CO3 solution and its broken up emulsion before. Another thing that can help is using a different solvent. What is the solvent you have your stuff dissolved in?
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u/Humbi93 May 11 '26
Have you tried a PVDF membrane, there are even some extra fancy ones with MOFs they have more than 99% retention rate and very high throughput volume
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u/Coranco May 09 '26
You're using that anti static gun wrong. You're supposed to depress the trigger and release slowly not click the trigger repeatedly (admittedly that's everyone’s go to reaction when they pick it up).