The Second Law of Thermodynamics

Is it not true that the Second Law of Thermodynamics is contradicted by the known facts of diffusion? When, for instance, masses of hydrogen and nitrogen are separated by a palladium partition, a difference of pressure is set up, owing to the diffusion of some of the hydrogen into the compartment which at first contained only nitrogen. In this condition the system is able to do work at the expense of its own heat, or heat entering from without. The palladium, in fact, takes the place of Clerk Maxwell's Sorting Demon, though, in this case, the process cannot be made continuous.