Semipermeable membranes - (Aug/25/2019 )

Hello

What it the pressure needed for water to pass through a semipermeable membrane that is permeable to water but not ion solutes?

Thanks

None - they work on osmosis.

But in this video, they have a water solution inside a semipermeable membrane and it does not leak:

https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Solutions_and_Mixtures/Case_Studies/Dialysis

So how does water pass through the membrane without pressure?

It is passing through - by osmosis - from high concentration to low concentration. It's just that it is coming out in molecular form and evaporating. The holes are too small for water to squirt/drip out of, but I bet if they left that membrane to sit it would dry out eventually.

Is there any method of semipermeable separation with higher water throughput?

What's the application? To concentrate the solute or to get pure water out?