How does critical temperature affect adsorption?
Higher critical temperature = more adsorbed.

So, what is critical temperature? When gas is heated above it, it can't become liquid, even if you'll increase pressure. Why? Because it's large kinetic energy makes intermolecular forces kinda "irrelevant". And adsorption is all about those forces.   

High critical temperature means that gas particles are good in intermolecular forces - "tenacious". This allows them to adsorb (cling to surfaces) more easily than those that won't hold on (low critical temperature).