To understand extraction, here’s a short list of topics you should try to understand well enough to explain to a non-expert.
Solubility and solubility curves
Miscibility
Polarity
Once you understand the fundamentals of extraction well enough, you’ll understand why the spray wash method is quite effective at producing “crude” products that need minimal post-extraction refinement, and why that process was designed the way it was.
Then, study and understand filtration and separation.
Depth filtration
Size-based exclusion
Absorption
Adsorption
Precipitation
Distillation
Crystallization
This combined with the extraction topics should help you understand the 101 of membrane systems - and almost every other thing we do around here - and why they are designed the way they are, and what you need to know/ask about when selecting vendors.
A dedicated month or three of learning should get you to the point where you can find your own answers, ask intelligent questions of experts in this field, and be far less likely to get taken for a very expensive ride by someone who talks fast and slick but doesn’t actually know what they’re talking about.
Looking for books with “handbook” in the title will probably speed up your learning.
Good luck.