What you're picturing has a name: https://en.wikipedia.org/wiki/Fritted_glass https://en.wikipedia.org/wiki/Fritted_glass. It's used in a https://en.wikipedia.o

What you're picturing has a name: https://en.wikipedia.org/wiki/Fritted_glass https://en.wikipedia.org/wiki/Fritted_glass. It's used in a https://en.wikipedia.org/wiki/B%C3%BCchner_funnel https://en.wikipedia.org/wiki/B%C3%BCchner_funnel instead of filter paper, to efficiently separate liquids from solids. Also, if you take some fritted glass and wrap it around a solid core, such that the holes don't go anywhere — i.e. they're just pits that water molecules (but not anything larger) can enter, and then get stuck there by surface tension — then you've get https://en.wikipedia.org/wiki/Molecular_sieve https://en.wikipedia.org/wiki/Molecular_sieve s.