Oh, I haven’t even considered the problem of the low concentration in the air. The problem of the energy loss from conversion alone makes capturing a net loss,

Oh, I haven’t even considered the problem of the low concentration in the air. The problem of the energy loss from conversion alone makes capturing a net loss, even if we assume 100% pure CO2 and theoretically perfect processes. Not putting it into the atmosphere in the first place is the only viable option. Otherwise you spend at least the same energy again just to undo the initial pollution. Practically it’s much worse.