COMPARATIVE-STUDY OF THE BEHAVIOR OF EXPERIMENTAL POLYAMIDE UF MEMBRANES - THE EFFECT OF POLYVINYLPYRROLIDONE USED AS AN ADDITIVE

New polyamide membranes for ultrafiltration were obtained by employing two types of nonwoven support. The effect of some parameters on the structure and the ultrafiltration performance, and the influence of the type of support on the membranes were studied. The membranes were characterized by ultrafiltration tests and scanning electron microscopic observations. The effect of polyvinylpyrrolidone on the properties of the membranes as well as the influence of the pH of the protein solutions are discussed. The results show that an increase in support thickness causes a large decrease in flux and retention, while the addition of polyvinylpyrrolidone decreases permeability. The influence of pH is explained by conformational changes and charge effects in the solute deposited on the membrane.