# What chemical could be used as carbon monoxide scrubber?

I am trying to produce nitrogen by passing air over a heated tube of coals. This leaves a mixture of $$\ce{CO},$$ $$\ce{H2O}$$ and $$\ce{N2}.$$ Only $$\ce{CO}$$ is unwanted in this case.

Could I use calcium hydroxide to scrub carbon monoxide out of the gas? What other substances could be effective?

edit: this is part of challenge to make other chemicals from natural resources, therefore i have to obtain nitrogen myself instead of buying it

• If you just want pure nitrogen, locate your nearest specialty gas company. Cylinders of nitrogen are danged cheap. And any welding shop has pure argon if you just want something pretty inert. Feb 22 '21 at 20:21
• Whole this is particularity bad and convoluted idea Feb 23 '21 at 0:09
• CO could be absorbed in solution of copper(I) chloride in ammonia or hydrochloric acid. ( almost insoluble in water ). But I am not sure about residual CO left and using the reagent may affect the intended nitrogen usage, unless cleaned up. Feb 23 '21 at 5:42
• @joncuster It is definitely the easiest and preferred way, but the OP may want just small volume. The whole cylinder may be "a cannon for a sparrow". It would help if the purpose was revealed, if he really needs nitrogen, or just a gas without oxygen. For the later, CO2 would be easier way. Feb 23 '21 at 5:52
• It is an experiment done for the pleasure of doing it? OP please explain. Otherwise buy N2. And what about CO2? There should be some, although is easy to be scrubbed away. Feb 23 '21 at 14:52

## 1 Answer

Air reacting with charcoal will produce $$\ce{N2},$$ $$\ce{CO}$$ and $$\ce{CO2}.$$ $$\ce{CO2}$$ will be absorbed by calcium hydroxide or sodium hydroxide.

However, $$\ce{CO}$$ cannot be absorbed at ordinary temperatures and pressures. Only at $$\pu{200 °C}$$ and $$\pu{10 atm},$$ it reacts with $$\ce{NaOH}$$ to produce sodium formate $$\ce{HCOONa}.$$

Finally, $$\ce{CO}$$ can be oxidized into $$\ce{CO2}$$ by passing over hot $$\ce{MnO2}$$ or $$\ce{Fe2O3},$$ and then be absorbed by a hydroxide.