Osmotic pressure and transport coefficient in ultrafiltration: A Monte Carlo study using quantum surface charges

The calculation of the Osmotic Pressure and the Diffusion Coefficient, characterizing the cake layer developing during the Ultrafiltration (UF) of Bovine Serum Albumin (BSA), through a Multiscale Model based on Quantum Mechanics (QM) and Monte Carlo methods (MC) was the aim of this work. From the ab-initio results described in previous works, the distribution of the BSA surface charges was used. A home-made Metropolis MC algorithm, aimed at simulating the formation of BSA loose or concentrated layers during membrane operations, was also implemented. In such a MC algorithm, a DLVO energy calculation methodology of the adsorbed system was developed. Different MC simulations and Hypernetted Chain theory (HNC) calculations were performed so to determine both the Osmotic Pressure and the Diffusion Coefficient of BSA according to the Chun and Bowen approach, thus allowing a comparison between the calculated values of osmotic pressure and a set of experimental data taken from the literature. Such a comparison showed a good agreement between the simulated and the experimental results.