I am interested to hear if anyone has explored post extraction Ethanol/ Oil filtration using membranes? I am hearing that Fats, lipids and Chlorophyll can be removed through a membrane and the Ethanol can also be removed through a second membrane?
Anyone have any thoughts?
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No experience myself, certainly curious. Why dont you tell us about some of your koch systems, the capabilities, and a bit about your company?! Welcome @Filterguy1 !
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There are a couple of companies working on it commercially and in the market place. Use the search bar as at least one has a staff member on-line here. At bench, talk to Sterlitech (Ethanol Resistant Nanofiltration for A Simple and Efficient Cannabis Extraction Method).
Removing coagulated (ie winterized) contaminants is easy… if you don’t foul the membrane. I’ve personally tried to remove chlorophyll from ethanol and acetone extracts and found that the “cut” resulted in a lot of CBDa in the waste stream. And again, removing solvent (to a point) is easy. It is a similar application as making maple syrup, except you need to use a membrane that is suitable for organic solvents (most aren’t).
While separation in water relies more on charge repulsion than size exclusion, in a non-ionic solvent, you are left on with size exclusion. With the various steric hinderances that occur, separation is an inexact science. Maybe best to avoid extracting chlorophyll in the first place. Then removing coagulated waxes and lipids from CBDa/THCa is relatively easy - if you don’t foul the membrane.
I’ve spent my entire career working in the membrane science space… any other questions?
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Filterguy1 - Y’all work with Koch membranes? Have Manwinder Singh reach out to me and we can work the problem. He was a scientist and engineer before he became a CEO. We go back 20+ years.
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I’ve been pondering this idea for a while. Eyeballing my reverse osmosis system… use the exact same lineup sediment-> granular carbon-> block carbon-> membrane… all stainless and all filters/seals etoh safe… wash filter roto… that would be awesome. Any idea if such a membrane exists?
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Yes, evonik makes them.
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I recall being told by a chemist that molecules in solution are not rigid in form and can essentially be squeezed through various sizes to a certain degree. He told me these filters are not as simple as they are being marketed as. Can any chemists in here confirm this?
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Can you provide a link? Cant find it on their website.
Seems like duramem is about perfect… 
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Tread I started a while back with plenty of info happy reading
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I’m getting my hands on a small Sterlitech / Evonik unit just to show proof of concept.
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Let me know what you find! Seems a great way to save tons of time!
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When I say small, I mean mL’s per hour
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Has anyone tried the Evonik filters? I saw them at Concentration Expo and it sounded great but they didn’t have any industrial systems operational.
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Sterlitech claimed the largest Evonik membrane they know of being used on cannabis actively does 25 L/hr of ethanol removal from crude.
I’ve also physically seen one in a cannabis facility that I’m pretty damn sure can do more than that. But I never got to see it run.
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I’ve used them at bench-scale, as well as a few others. Your typical RO membrane will have compounds that are not compatible with ethanol. You need to find an organic solvent compatible RO (or a tight NF) for a desolvation application. Most of the patents I’ve seen so far probably won’t be defensible. There is prior art out there from other industries that makes the application “obvious” to an individual “learned in the art”. Membrane separations at the molecular scale can be tricky. Salt removal from water uses mostly charge repulsion of the anion to reject salt, with the cation “pairing” to maintain neutral charge. Very small neutral molecules are poorly rejected. To complicate this, the surface charge and steric hindrances change with pH. For organic solvents with a neutral molecule, size exclusion matters more. The complicated shape of the molecule, temperature, pressure and concentration differential all matter.
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That’s the largest one that Sterlitech sells. Evonik makes one module (8040 series) that should do 100 L/hr per unit. You can also put them in series to get the result your’re looking for. Not cheap, but still looking pretty promising.
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Hello,
Heyes Filters Inc. has been selling filtration products into the F&B and Biotech/ Pharma industry for 33 years here in Los Angeles. We have filtration solutions for the small and larger Canabis producers for both Calrification (Gross solids removal) and Carbon treatment for Color and Odor removal. We do work with Koch Membranes in the wine business but I believe that the MF spectrum they provide is oversized currently for most Cannabis operations. We have a variety of separation methods that we are currently selling into this industry with great success.
Let me know if we can be of service.
Cheers
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