Air reacting with charcoal will produce $\ce{N2, CO and CO2}$.$\ce{N2},$ $\ce{CO}$ and $\ce{CO2}.$ $\ce{CO2}$ will be absorbed by calcium hydroxydehydroxide or sodium hydroxide. But
However, $\ce{CO}$ cannot be absorbed at ordinary temperatures and pressures. Only at $200°C$$\pu{200 °C}$ and $\pu{10 atm}$,$\pu{10 atm},$ it reacts with $\ce{NaOH}$ to produce sodium formate $\ce{HCOONa}$.$\ce{HCOONa}.$
Finally, $\ce{CO}$ can be oxidized into $\ce{CO2}$ by passing over hot $\ce{MnO2}$ or $\ce{Fe2O3}$,$\ce{Fe2O3},$ and then be absorbed by a hydroxide.