Separation and reaction method utilizing an oxygen ion transport element

A method of separating oxygen from an oxygen containing feed and reacting the oxygen with a reactive substance, said method comprising:

• contacting the oxygen containing feed with a cathode side of an oxygen ion transport membrane element and permeating the oxygen through the oxygen ion transport membrane element by oxygen ion transport from the cathode side to an anode side thereof;
• the oxygen ion transport element having a self-supporting dense layer and a surface porous feature in contact with and supported by the dense layer, each of the dense layer and the porous surface feature being capable of conducting oxygen ions and electrons, the porous surface feature at least in part forming the anode side of the oxygen ion transport membrane element and having a thickness less than that of the dense layer, a greater surface area than that of a surface of the dense layer adjoining the porous layer and a pore aspect ratio of pore size to pore length of pores defined in the surface porous feature of between about 0.1 and about 5;
• contacting the reactive substance with the anode side of the oxygen ion transport membrane element at the porous surface feature thereof and reacting the reactive substance with the oxygen permeated through the oxygen ion transport membrane element;
• and
• the reaction providing a driving force for the oxygen ion transport.