| Abstrakt: |
Rheology assessment is an important tool to understand membrane process formation as well as membrane morphology and properties. Hence, by varying the GRAFIM® content and adding silver nanoparticles, polysulfone composite membranes were prepared through the wet-phase inversion method with N-methyl-2-pyrrolidone as a solvent and water as a nonsolvent. Newtonian fluids were obtained, and silver nanoparticle dispersions presented the highest viscosities. Water diffusion was Fickian in both systems, and their coefficients decreased by increasing their viscosity. Dense surfaces characterized GRAFIM® membranes, whereas nanoporous surfaces were present in silver nanoparticle membranes due to their higher dispersion viscosity. Both thermodynamical favoring and rheological hindrance led to membrane formation. GRAFIM® and silver nanoparticles positively influenced water sorption, linear expansion, porosity, and hydrophilicity. Finally, these membranes presented high values of water permeability due to their high porosity, cutoff in the range of nanofiltration, which were lower for the membranes with only GRAFIM® and favorable values of saline rejection for four used salts (NaCl, Na2SO4, MgCl2, and MgSO4). [ABSTRACT FROM AUTHOR] |
