In my lab we don't use any charcoal/carbon filters but when discussed (we are a bunch of chemistry and engineering nerds so we talk about EVERYTHING down to gardening science) it's always been surface area. The department of natural resources made us start recovering propellants back in like 2010 out in the factory (another town) and it looked like a plastic mesh filter you would put in an air handler box in your HVAC at home. Then they send that off and have it "cleaned" and returned for re-use. Plastics are carbon chains but I can't piece it together how it works.

 

Thanks for the reminder - it’s one of those details that just keeps escaping my brain every chance it gets. This time I’ll trap it for good!

I think the technical term for the material is “activated carbon” but I remember drawing the parallel to charcoal when I learned that so that’s just how I state it most of the time.

I’m sure the chemistry (and therefore the material) of trapping fuel vapors differs depending on the fuel - considering there’s different evaporation rates for each (and in different temp ranges), it makes sense. Just curious - How large are the filters you work with (relative to an EVAP canister)?