Effect of lipid nanoparticles inclusion on transport parameters through regenerated cellulose membranes

Two highly hydrophilic regenerated cellulose planar sheets (RC-6 and RC-MD) with different morphological, structural and transport parameters were used as supports of lipid (lecithin-triestearine) nanoparticles (RC-6/LNPs and RC-MD/LNPs samples), which were embedded by immersion in a water dispersion of LNPs. Salt and ions transport (salt diffusion, ion transport numbers and effective fixed charge) were determined from measurements carried out with the samples in contact with NaCl solutions at different concentration and, consequently, osmotic pressures. Results do not show differences in the small fixed charge of the membranes as a result of nanoparticles inclusion (−0.012 M and −0.008 M for RC-6 and RC-MD, respectively) and stability of the LPNs-modified membranes for osmotic pressure up to 5 bars was established. TEM images shows the presence of LNPs in the RC-supports and Raman spectroscopy analysis was used for physic-chemical characterization of the RC-supports and RC/LNPs-modified membranes but also to determine the stability of modified samples under flow conditions. Different transport behaviour depending on the RC-support was obtained, and results seem to indicate the maintenance of nanoparticles into the dense RC-support structure till a concentration gradient of 0.1 M.

Research highlights▶ Hydrophilic RC membranes were modified by inclusion of lipid nanoparticles (LNPs). ▶ The presence of LNPs does not modify the RC-supports electrical parameters. ▶ LNPs cause a certain compaction of the membrane structure affecting mass transport. ▶ Stability of RC/LNPs-membranes for osmotic pressure up to 5 bars was established.