Sciencemadness Discussion Board

Emulsion and bubbles problem

Trizocy - 12-5-2015 at 07:05

Hello

Looking for some help to understand why this is happening, and is it possible solve this problem :)

I got a Separatory funnel with a long stem adapter attach to it. Inside the sep funnel i got 2 liquids, water and naphtha. The naphtha is running through the water with the help of the adapter.

But over time a huge emulsion appear (lots of bubbles). And i can see inside the sep funnel when the emulsion is thick enough of bubbles, some of the bubbles will begin to float and float to the top and out of the sep funnel. So after 20mins i can see that the water layer is reduce because of the bubbles. (Though that the water will always be at the bottom even if its was a bubble)

So why is this happening :)?

Thanks

Zephyr - 12-5-2015 at 08:09

Emulsions occur when two imiscible liquids become mixed, this usually happens when they have similar densities.
I'm not sure that I really understand the situation, are you trying to separate the layers?
If so, this can be done several ways, most simply just letting it settle over time. If this fails, try adding more of either liquid, or adding salt to the aqueous layer.

Chemosynthesis - 12-5-2015 at 10:35

It happens sometimes when the Gibb's free energy of mixing is favorable in otherwise unfavorable systems. Heat can also speed up the kinetics of de-emulsification, and a very common way to rid a liquid-liquid system of emulsions is to saturate the aqueous layer with NaCl or a similar salt (as mentioned by Pinkhippo11), as the hydration shell diminishes system entropy.

Trizocy - 12-5-2015 at 13:15

Hmm thanks!

So heat can help to de-emulsification the bubbles faster?
The sep funnel are in a storage room outside the house (not isolated) so its pretty cold outside. So maybe that is the problem :)?

Thanks ;)

blogfast25 - 12-5-2015 at 14:12

Quote: Originally posted by Trizocy  
Hmm thanks!

So heat can help to de-emulsification the bubbles faster?
The sep funnel are in a storage room outside the house (not isolated) so its pretty cold outside. So maybe that is the problem :)?

Thanks ;)


Heat may help. Try adding something like CaCl2 to the water, if practical of course...