Which method involves a semi-permeable membrane that allows oxygen to pass through more easily than nitrogen?

The method involving a semi-permeable membrane that allows oxygen to pass through more easily than nitrogen is membrane separation. This technique utilizes membranes designed with specific properties that preferentially allow certain gases to permeate while restricting others. In the context of oxygen and nitrogen, the semi-permeable membrane is structured so that oxygen molecules are smaller or more readily able to diffuse through the material than nitrogen molecules. This results in a higher concentration of oxygen on one side of the membrane compared to the other, effectively separating the two gases.

Membrane separation is widely used in various industrial processes, particularly in applications like producing nitrox gas mixes for diving, where specific concentrations of oxygen and nitrogen are necessary for safety and efficiency. This process not only enhances the purity of the desired gas but also optimizes the overall production of gas mixtures tailored for varying oxygen needs in diving situations.