Is there a centralized source for winterization membrane solvent compatibility? I am looking to use non-traditional/green solvents in extraction and I know they are weird with what materials they can be used with.
For membrane solvent compatibility specifically? Not to my knowledge. There are sources solvents and plastics though. You’d have to tell use which solvents you’re using and/or which filters.
Cotton, borosilicate, and PTFE micron filters are pretty resilient when it comes to solvents.
Which solvents are you looking for specifically? Should be able to source them for you, we are located centrally in the US (Chicago suburbs)
Turns out you also have to worry about how the membranes are affixed to the housings….(see below)
1 Like
No.
I’ve purchased custom-rolled membranes from specialty companies that were claimed to be resistant to a specific solvent, but when they were introduced to that solvent, all of the adhesives dissolved into the process stream.
I’ve talked to membrane vendors who sell to this industry specifically who did not see this as a problem until I pointed out that we don’t want random polymers in our finished products, and neither does the regulator.
Some of the larger manufacturers will give you some compatibility details. Most will not. The ones that do usually charge you “oh fuck that noise” prices for their membranes.
If you’re lucky, and you get a list of the materials of construction from the vendor, that’s great! Right? Not necessarily.
There are frequently multiple grades or types or formulations of given materials. There are variations/formulations of some rubber based materials that are fine with alkanes, and there are some (uncommon ones) that are not.
Temperature also has an effect on compatibility.
Most manufacturers will not tell you what type of glues, wraps, or other materials are in their elements. I suspect that many don’t know because their membrane production is farmed out to other companies or they just don’t care.
There are a handful of common polyurethane based glues used in membrane production. Some are fine with certain solvents or parameter ranges, others are not.
If you get the list of materials, and you check the good ol cole-parmer compatibility table, you may have an idea if something is worth rolling the dice on.
But just because something is listed as an A compatibility does not mean that your specific material from your specific vendor will not dissolve on first contact, and that it will not leach something into your process stream.
And just because something is listed as a D compatibility does not mean that it will not work in your application. Notice that all compatibility tables list a “this is for informational purposes only” type statement? There’s a reason for that. They’re all compiling data from a boatload of sources of various quality.
Material compatibility of materials and various solvents is an extremely deep PhD level topic.
Good luck.
3 Likes
Also, good luck with this.
If your job is “winterization” aka excluding lipids, waxes, and other cold-precipitatable nasties, you may find that membrane that works fantastic in solvent A may do a completely shite job of it in solvent B.
In solvent A it may exclude functionally 100% of what you want to exclude. In solvent B it may allow a significant % of them forward. And it may do it at 1/10 of the total rate.
Even if A and B are alcohols. Even if you keep temperature and pressure constant.
Even if the vendor told you it should work just fine … they got your money, didn’t they? Problem solved as far as they are concerned.
Considering that you’re trying to exclude at least two or three classes of compounds in differing molecular size ranges… it’s somewhat amazing that the industry has found any that work at all.
3 Likes
lol ngl based on your two posts i’m just abandoning that direction.
2 Likes
d-limonene, acetic acid, dipentene, and then a few others i don’t really want to mention right now.
if you can get me a membrane/glue that works we’re willing to pay full price all that shit.
Probably a good call.
If you decide to get creative with membranes, and you can find a membrane flat sheet that works for your application, Henkel adhesives would probably be able to recommend a glue that would work.
If I had to pick a number out of the air, I’d say it’s a $100,000 - $500,000 venture to find, validate, and select a membrane that will work for a novel application.
Might be less, could be a lot more. On the low end, that’s assuming you build your own skid/test rig, do all of your work in-house, and your hours are “free.”
And there are zero guarantees of success. We tested a LOT of membranes for a certain application and never found one that met our performance targets, and the closest ones were priced at “lol no” levels.
4 Likes
Not sure if you are still going to go that direction with the membranes but I will shoot you an email with our pricing sheet for solvents if that is cool. My email is lukec@shopbvv.com, if you want to send me an email or DM me your email I can send over that pricing sheet!
i would probably just start with graphene, cause i know that is compatible and different conformations, but yea my worry is that it will just take everything out and the overall hit to yield will be an issue.
No membrane that I am aware of is pure graphene.
If you mean the graphene elements that Zev is selling, I’m the one who discovered those membranes, and I was the first paying commercial customer of the OEM globally… there is a lot more to those than just graphene. The flat sheet is graphene bonded to a support layer made up of a polymer. The modules are assembled with adhesives and other components.
In theory Zev should be able to provide you material compatibility information for them.
7 Likes
That is the one I was referring to, he said he didn’t have much in the way of information for compatibilty with the solvents that I was interested in. Actually after I got off a video conference with him, I checked this thread and was like, yea fuck this route, I’m pretty I could find a different method to do what I want that would be cheaper and faster to implemenation.
Almost certainly.
Magic dirt of various types is certainly a much faster way to get the same cleanup result of a lot of membranes.
The consumable cost is massively more with magic dirt though.
Using extreme cold to precipitate undesirable compounds is simple.
Ultra low freezers are expensive and that whole process is an expensive messy bitch to manage.
Thermal recovery methods are much simpler to implement than membrane solvent recovery.
Your opex will be probably 10x what it would be with membranes.
Any job a membrane does, there’s a decent non-membrane option for doing it.
It’s just going to cost you a lot more in ongoing costs. And might not save you anything up front.
Membranes are a fantastic optimization tool, once you’ve got them in your toolkit. Getting there is somewhat less than simple. I’ve been working with them in our industry since… 2018?
It’s only in the past couple of years that I’ve got really comfortable with them, but I hesitate to pretend that I really know anything at all on the topic.
Oh, and here’s another fun rabbit hole I’ll shine a light on:
Spiral wound membranes aren’t the only type/format of membranes out there. Some of the other types are extremely useful as well, regardless of the solvent you’re using.
4 Likes
More than likely. Also it’s questionable whenever anyone without a multimillion dollar buildhouse and Raman supported spectra for QC says they have “graphene”. It’s more than likely graphite with small quantities of graphene flakes. Scaling up to sheets of graphene is a royal bitch.
Borosillicate sheets in a hochstrom filter will work for your purposes, but won’t scale up easily unless you do multiple stages and start with warm scrubs. I’ve used the BVV refinement funnel, pressurizing with N2, and gotten good results with EtOH as the solvent. It’s messy and annoying though.
I’ve had decent luck using hollow fiber membranes for winterization. Albeit, they were only used for a final filtration after the majority of lipids were removed with a centrifuge. It was nice being able to back flush them when they fouled.
2 Likes
I’m not going to get into an internet pissing match over this but I somewhat regularly chat with the inventor, and did much of the preliminary research validating them for use in our industry.
It is my understanding the membranes on offer are actually graphene oxide. The person/team who invented them published papers on the process/topic in multiple high quality journals, including one in Nature. They’ve got decades of person-years invested in the manufacturing process.
And they’re still a bitch to manufacture, from what I understand.
I’m not going to say any more on the matter because I’m not the one trying to sell them, Zev can choose if he wants to disclose anything further about them or not. (I suspect not.)
2 Likes
That is indeed one of the useful uses of hollow fibre membranes.
Sounds like he has the $$$$ buildhouse and raman spectra to back it up! I never said Zev in particular doesn’t have a pure graphene product, but I’ve seen enough folks publish their supposed graphene results while still having shitty QC spectra that indicates otherwise. Cool article on the topic. I only know this because I was tasked in grad school to buy graphene material from numerous vendors and test it for hydrogen adsorption. It sound like Zev has the process down and that’s great to hear.
2 Likes
Ooh that is cool! Unless I’m mistaken, the membrane material that we’re discussing is single layer, but I’d have to go back to the original literature to double check, it’s been a couple of years since I went through all of that.
I don’t want it to seem that I am implying that anyone is doing something he’s not, so to be clear: It is my understanding that Zev is selling membrane elements that have been rolled from membrane flat sheet that has a graphene functional layer. That flat sheet is produced by an independant separate company, is run by the person who invented the graphene membrane production process/methods, and that person oversees the membrane production.
As far as I know, until I introduced him to the OEM, Zev was not in any way involved in the development of the membranes other than providing his desired construction details to the company that rolls/assembles them, and then marketing them to our industry, and providing any feedback to the manufacturer.
I had no issues with the functional layer in any of the many small or large graphene membranes that I tested in our facility. In certain applications, I had issues with some of the original adhesives and other assembly materials, which is why Zev’s modules are produced with a different construction than the first ones that we got our hands on - which had been designed and commercialized for a different industry.
I have reason to believe that the support layer that the functional graphene layer is deposited on may degrade at an accelerated rate in certain solvent and process combinations, but I don’t believe that that is an issue that anyone else in this industry would run into, other than specific individuals who would already be aware of the potential issue.
From what I understand, the membrane elements that Zev is selling have been rolled with materials that should be compatible with the standard solvents and processes used in our industry. I do not have direct knowledge of what those materials of construction are, and I have not tested any membranes of the construction that Zev is selling, as I only ever tested and used membranes that I received directly from the OEM.
And before anyone asks, no I don’t intend to connect anyone to the flat sheet OEM directly. You wouldn’t save any money trying to go direct to them instead of buying from Zev, and I very much doubt you would have an order size that they would consider worth producing.
If someone wants me to consult on membrane applications in our industry or others, I’m happy to discuss doing so - it’s possible that you might have an problem that would be best solved by a discussion with the graphene OEM, but it’s unlikely.
3 Likes