Multi-scale modelling of manufactured nanocomposite membranes with polymeric matrix

Polymeric membranes are widely used in water filtration applications due to their low cost and ease of fabrication. In this study, the changes in the properties and performance of PVDF/PVP membrane composed of polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) and PSf/PVP membrane composed of polysulfone (PSf) and PVP were investigated using cellulose nanocrystal (CNC) and cellulose nanofiber (CNF) reinforcement. PVDF/PVP and PSf/PVP based membranes were reinforced with 0.5 and 1 wt% CNC or CNF and the effect of the reinforcement ratio on the improvement of membrane properties and performance was demonstrated. All flat sheet membranes were fabricated by non-solvent (water) induced phase inversion method. Surface morphology, roughness, crystallinity, porosity, average pore size, water content, mechanical properties of the fabricated membranes were characterized. Pure water and surface water flux performance of the produced clean membranes were determined in a dead-end filtration setup at 3 bar. The pure water fluxes of fouled-cleaned membranes, which were physically cleaned with distilled water for 15 minutes after surface water filtration, were determined at 3 bar. Flux recovery ratio (FRR), total fouling ratio (Rt), irreversible fouling ratio (Rir) and reversible fouling ratio (Rr) of the membranes were determined to evaluate the fouling resistance performance of the membranes. The surfaces of the fouled-cleaned membranes were characterized by scanning electron microscopy (SEM) to further investigate the fouling resistance of the membranes. The difference between the morphological properties of PVDF/PVP-based and PSf/PVP-based membranes produced by phase inversion was explained by Hansen solubility parameters. In the last section of this study, the elasticity modulus of the nanocellulose reinforced nanocomposite membranes were estimated by various modelling techniques (Mori-Tanaka, Finite Element, Voigt-Reuss, Self-Consistent and Halpin Tsai). The results obtained from the modelling studies were compared with the experimental results (tensile test results) and the prediction success of the modeling methods was demonstrated. This is the first comprehensive study to investigate the effect of two nanocellulose types (CNC and CNF) and two reinforcement ratios (0.5 and 1 wt%) on improving the properties and performance of two polymeric membrane matrix (PVDF/PVP and PSf/PVP) commonly used in membrane production. The elasticity modulus of nanocellulose reinforced (CNC, CNF, CNC-CNF) PVDF/PVP and PSf/PVP membranes, which are planned to be used in water filtration applications, was predicted comparatively for the first time in this study with different modeling methods.