You might be interested to learn of Climeworks if you're looking for a more reliable way to remove emissions than planting trees (which is, indeed, mostly not really working as well as too slow).
This looks a lot like what I was thinking of. They don't provide much information about their extracting filter, but after the CO2 is extracted it is compressed into water creating carbonic acid, then injected it into a suitable basalt formation with an impermeable cap so that carbonate salts could form[1]. They claim all the injected CO2 could become carbonates in under 10 years[2].
If this works like they say, then it's cause for hope.
I've seen those designs but never looked too deep into them. Maybe I've seen too many of the 'collect water from thin air' devices and become cynical. If their 90% efficiency is counting manufacturing and power costs then it could be worthwhile in cities and other areas with high atmospheric carbon levels. Same problem as the trees though, if we leave them out or use them for something they'll break down and be back in the carbon cycle. However we collect the carbon we need to lock it in place.
I would guess that 90% does not include R&D and is only about the general production costs like from manufacturing and building. So with scaling up (if they don't do R&D but just add a plant) it should be 90%.
It's a good question though, perhaps worth asking them.
