Influence of pH on permeability of ceramic membranes and selectivity in ultrafiltration of model BSA and myoglobin solutions

The results of ultrafiltration tests carried out with model BSA and myoglobin solutions using ceramic 50 and 150 kDa membranes have been presented. Membrane permeability and selectivity were investigated in function of pH, transmembrane pressure (TMP) as well as molecular modelling data for proteins such as size, geometrical parameters and pH of minimal free energy of folding. The study has shown that the permeate flux J(v) depends on TMP, whereas the protein rejection is mainly influenced by pH. The results demonstrated that molecular modelling data are not sufficient to explain the membrane behaviour and the membrane–protein charge interactions and fouling effects must be also considered to explain the rejection mechanisms.