How does it perform in the real world, where water is contaminated with far more than microplastic - is this filter selective for plastic or will it get gummed up by literally anything?
I don't know how much you know about water filtration plants, but in the real world everything is a series of filters, each more fine-grained than the one before it. You would never use this on unfiltered ocean or waste water - it would be yet-another-stage in the filtration pipeline, after many of the others and possibly before a few more.
Personally I often wonder why things like the seaweed for cows that reduces methane emissions by 99% is not everywhere by now, and we are resorting to masks to trap gases from their breathing and farts.
Is the solution scalable? What does it cost?