https://phys.org/news/2020-04-antiviral-membrane-mask.html
I had actually independently thought of a very similar (but not identical) idea (because its obvious) and I am now glad to find at least one expert is working on it.
What he is working on is a membrane (presumably to be incorporated into a face mask) that not only filters the virus out from the air but deactivates itI That's good but I personally I think that could be a bit of overkill because I think just filtering it out would be good enough and this would be the easier and quicker goal. This would require making a membrane with hole sizes so small that the virus cannot squeeze through while at the same time design the holes so that they are such that they allow air to move through them without too much frictional forces so you can simply breath through it without too much effort. I guess that would actually be quite tricky to design.