“…This confi guration is similar to that reported most often in the recent literature, for example, by (Mallada, Men é ndez, and Santamar í a, 2000a ;Ramos, Menendez, and Santamaria, 2000 ;Tonkovich et al , 1996b ). However, it differs from those studies, where the shell side outlet was open, in that oxidant transfer over the membrane is infl uenced by diffusion (Farrusseng, Julbe, and Guizard, 2001 ;K ö lsch et al , 2002 ). Pressing all air over the membrane has the advantage of an easy control of the amount of air inserted.…”