Forum | Rebreather with a pump for life support?

Does anyone here know much about diving rebreathers?  I find the idea of using one of these as part of our life support system extremely appealing, for a lot of obvious reasons.  I'm just wondering if we can make it work with our design.  Obviously rebreaters are designed to be used with a tightly sealed mouthpiece in an underwater or vacuum environment.  This is different to what we want, which is the astronaut breathing freely in a cabin.  This is quite a naive idea, but could we take a rebreather and attach the mouthpiece to a pump which breathed in to / out off the cabin through a small pump, and expect it to work?

The biggest potential problem I can think of with this is that CO2 scrubbing might happen too slowly: if the astronaut exhales one breath's worth of CO2 into the cabin, it diffuses throughout the atmosphere and when the rebreather "breathes in" from the cabin it's only going to get a small portion of that breath of CO2, so the CO2 level will steadily rise.  Could we counter this by having the pump attached to the mouthpiece "breathe" faster than usual, or would this just overwhelm the CO2 scrubber?