ABSTRACT
Phase inversion is a suitable method for the preparing of polymeric membranes having all types of morphological structures. In this technique, a casting solution comprised of polymer and solvent is immersed into a non-solvent coagulation bath, and a polymer solution is phase separated into polymer rich and polymer lean phases in a controlled manner [1]. The solidification process is frequently started by the change from one liquid phase into two liquid phases (liquid-liquid demixing). At certain periods during de-mixing, the polymer rich phase solidifies so that a solid membrane matrix is formed [1,2]. Membrane morphologies, particularly the pore size distributions, can be controlled by selecting the different solvent, non-solvent, polymer, pore former, and fabrication parameters depending on the particular application [3–6]. Cellulose acetate is broadly applicable for the synthesis of membranes because of having tough, biocompatible, hydrophilic characteristics, good desalting nature, high flux, and relatively less expensive [7–9]. Cellulose acetate membranes with different polyvinylpyrrolidone (PVP) concentration and coagulation-bath-temperature were prepared by a group of researchers [10]. They have found that the addition of 0 wt.% to 3 wt.% of PVP to the polymer solution increased the macro-voids development and consequently the pure water flux was raised.
