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A comment on Unimpeded Permeation of Water Through Helium-Leak–Tight Graphene-Based Membranes. Parent comment

Re:Unimpeded Permeation of Water Through Helium-Leak–Tight G... by twawaaay on Wednesday February 15, 2023 @08:50PM (#34813903)
Of course. You want a high enough water flow to get the installation to filter lots of water. You have to have pressure above osmotic pressure. You can increase the flow of water through filter either by increasing pressure or by adding more filters.
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Re:Unimpeded Permeation of Water Through Helium-Leak–Tight G... by jojobas on Wednesday February 15, 2023 @09:00PM (#34813973)
No, it's just that there is a friction-like loss for getting any amount of water through the membrane. See here. https://sci-hub.ru/10.1016/j.desal.2015.01.005
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Re:Unimpeded Permeation of Water Through Helium-Leak–Tight G... by twawaaay on Wednesday February 15, 2023 @09:08PM (#34814041)
"The trends from the analysis presented in this paper show that in both seawater and brackish desalination we are approaching thermodynamic limitations."

That's excerpt from the article you linked.

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Re:Unimpeded Permeation of Water Through Helium-Leak–Tight G... by jojobas on Wednesday February 15, 2023 @09:12PM (#34814071)
No, it's not quite like that.

With pipes there's a linear (or quadratic for turbulent flow) resistance, low pressure still results in some flow.

With membranes you have a threshold pressure below which you get no flow at all.

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