Efficient Separation of Organic Dyes using Polyvinylidene Fluoride/Polyethylene Glycol-Tin Oxide (PVDF/PEG-SnO2) Nanoparticles Ultrafiltration Membrane

This work studies developing ultrafiltration (UF) membranes using organic and inorganic additives to remove organic dyes at UF conditions with high effectiveness. Flat sheet (18 wt%) polyvinylidene fluoride (PVDF) membranes were prepared via phase inversion and then developed by adding 6 wt% polyethylene glycol (PEG) as a pore former. Furthermore, the PVDF/PEG membranes were developed by embedding tin oxide nanoparticles (SnO2 NPs) with different contents of 0.3, 0.6, and 0.9 wt%. The prepared membranes were examined for their performance in the dye removal before being characterized using the field emission scanning electron microscope, atomic force microscopy, contact angle, Fourier-transform infrared spectroscopy, surface charge, porosity, mean pore size, tensile strength, and elongation at break. The performance was tested regarding pure water flux (PWF), permeate flux, and dye removal (R%). The effect of dye concentration and pH of the feed solution on the permeate flux and R% was also investigated. In addition, the antifouling features in terms of flux recovery ratio, reversible fouling, irreversible fouling, total fouling, and the R% were studied using the PVDF/PEG membrane and the membrane containing 0.3 wt% of SnO2 NPs. The contact angle decreased from 78.85° to 51.88°, and the PWF rose from 7.16 to 135.71 L/m2.h for PVDF and PVDF/PEG-SnO2 (0.3 wt%) membranes, respectively. The R% of rhodamine B (RhB) slightly decreased from 93.08 to 91.26, and 87.71% for PVDF, PVDF/PEG, and PVDF/PEG-SnO2 (0.3 wt%) membranes, respectively. Then, it increased with increasing NPs concentration up to 90.17 and 92.23% for PVDF/PEG-SnO2 (0.6 wt%) and PVDF/PEG-SnO2 (0.9 wt%) membranes, respectively. Also, the molecular weight cutoff was calculated using RhB as a cationic dye, acid orange 10, and congo red as an anionic dye and it was 520 Da.