Question: how would you seperate carbon dioxide from the air using a filter?

Jarrod Hart answered on 16 Jun 2016:

Great question!!

This is actually a very real challenge that needs solving and if it was easy it would have been done already 😉

But that is no excuse not to try…

Because CO2 is such a small molecule, it is hard to physically filter – the membrane you’d need (called a ‘molecular sieve’) does exist, but is super expensive to make and super slow to work.

It is easier to find a material that absorbs CO2, such as sodium oxide or hydroxide (also known as ‘lime’). The trouble is, that we really need a heck of a lot – and it does not occur often naturally (I wonder why? oh yeah because it reacts with the air).

There are some other rocks, peridotite is best known, that do occur naturally, but still the amount is not yet enough and the cost of mining it and exposing it to the air is vast – and no one wants to pay – so far humanity is not panicking as much as perhaps it should!

Rather than taking CO2 out of the air (which is tough) it is also a good idea not to add any more CO2 to the air – so ways to capture CO2 before it is emitted are another area of focus for chemical engineers – it is called ‘carbon capture’ and one method is to compress it and pump it underground.

There are lots of ‘promising’ but often flawed technologies under development, it would take far too long to describe them here… so I tel you what – why don’t you study them and become an expert? You will for sure be in demand for your whole life!

In that case, I would be very interested to see what ideas you have to solve this really really important problem!