Modification of cellulosic membranes by γ-radiation: Effect on electrochemical parameters and protein adsorption

This work is focused on the study of possible changes in the electrochemical transport parameters of cellulose membranes due to the effect of ionising radiation. A cellophane membrane (membrane C5) was irradiated with a dose of 80 Gy (membrane Ir80) and differences in the electrochemical parameters for pristine and irradiated samples are studied. Salt permeability, ion transport number, permselectivity and electrical resistance for C5 and Ir80 samples were determined from diffusion, membrane potential and impedance spectroscopy measurements, which were carried out with the membranes in contact with NaCl solutions at different concentrations. Modification of the electrochemical parameters as a result of membrane irradiation was obtained, which seems to reduce the matrix free volume and to increase the negative character of the cellophane membrane. The possible effect of membrane modification on protein adsorption was considered by comparing the electrochemical parameters of C5 and Ir80 samples with those obtained with the membranes after fouling with bovine seroalbumine (BSA). Results show a decrease in the fouling effect for the irradiated sample and the increase of ion permselectivity for both fouled membranes, which seems to indicate the control of ion transport by the protein.