Fouling Mechanism Study of Nanoporous Membrane by Ultrafitration of Whey Proteins

One of the barriers during whey filtration using UF membrane is the fouling phenomenon of the membrane, which is caused by whey proteins. In this work, the UF membranes were prepared using polysufone (PSf), dimethyl formamide (DMF), 1 wt.% poly vinyl pyrrolidone (PVP) and different concentrations of LiCl via phase inversion induced by immersion precipitation. The prepared membranes were characterized using SEM, AFM, porosity and mean pore size measurements, ultrafiltration performance and fouling analysis. The roughness of the membrane surface increased after the addition of LiCl in the casting solution. The SEM images and the measured data of porosity and pore size showed that the porosity was significantly enhanced after modification with LiCl but the pore sizes of the membrane were reduced. The performance analysis of these membranes demonstrated that the modified membranes had higher pure water and whey flux in comparison to the neat membrane and all of the prepared membranes exhibited protein rejection higher than 90%. In order to evaluate the membrane fouling, the experimental fouling analyses were carried out and the Zedney's pore blockage and cake filtration model was employed. The membranes fouling in terms of pore-blocking slightly decreased after the addition of LiCl.