Effect of ionizing radiation on a ceramic microporous membrane

Characteristic transport and interfacial parameters for a microfiltration ZrO2/Al2O3 membrane (sample Z100S) were obtained from filtration, membrane potential and streaming potential measurements, which were carried out with the membrane in contact with different NaCl solutions, while membrane chemical surface was analyzed by XPS spectra. Electrical parameters indicate a weak electropositive character for the studied membrane. sample was modified by gamma-irradiation (dose of 10 J/kg) delivered by a 60Co Unit (membrane Z100S-Ir10). A comparison of the results obtained with pristine and irradiated samples shows: (i) ion transport numbers and electrical interfacial parameter (zeta potential) modification (anionic permselectivity increases from 9% for the untreated membrane to 23% for the irradiated sample); (ii) a decrease in the hydrodynamic permeability (around 10%); (iii) a reduction (18% approximately) in the atomic concentration of carbon, a non-characteristic membrane material element attributed basically to membrane manufacture. The presence of this element in the membrane structure could be directly related to the observed modifications, affecting the membrane behaviour as a result of the irradiation itself or associated to local heating effect.