Characterisation of two microporous ceramic membranes with different geometrical parameters: Effect of protein adsorption on electrochemical parameters

Two flat ceramic commercial membranes for filtration applications with similar composite structure (a fibrous stain steel network covered by a sublayer of Al2O3 particles plus an external layer of ZrO2) but different “nominal” pore size (25 and 100 nm) are studied. Chemical surface and morphological characterisation was carried out by X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM), while transport of NaCl solutions at different concentrations through both membranes was characterized by determining hydraulic and diffusional permeabilities, ion transport numbers and electrical resistance. n adsorption on membrane walls (membrane fouling) was considered by maintaining the membranes in contact with a protein solution for 48 h (2 g/l of bovine seroalbumin or BSA). The effect of protein adsorption on electrochemical parameters was determined by comparing the values obtained with clean and BSA-fouled samples. Results show reduction in diffusional permeability and increase in the electrical resistance (around 20%), but cation transport number hardly depends on membrane fouling.