That is not the case; carbon (as CO2) was captured by disposable LiOH cartridges through the end of the Shuttle program. On the ISS, it's captured on zeolite be

That is not the case; carbon (as CO2) was captured by disposable LiOH cartridges through the end of the Shuttle program. On the ISS, it's captured on zeolite beds and vented into space. Except for a few small-scale plant experiments, no space program has demonstrated carbon capture and re-use.