Effect of wetting agent on the dye filtration performance of ultrafiltration membrane

In this study, the wet phase inversion method was used for fabrication of the flat sheet ultrafiltration (UF) membranes. Three different polymer types and two different wetting agents were used for the fabrication. The effect of polymer types and wetting agents were investigated on the structural and dye performance of casted membranes. Two different synthetic dyes, 100 ppm Setazol Red and 100 ppm Setazol Blue, were used for the performance test. Viscosity, contact angle, and molecular weight cut off (MWCO) of casted membranes were measured and an electro kinetic analyzer, dynamic mechanical analyzer (DMA) and scanning electron microscope (SEM) were used to determine the structural properties. While the highest water and dye permeability were obtained with PES-PEG membrane, PSf-plain membrane gave the highest removal efficiency for Setazol Red and Setazol Blue dyes, which was found to be 78.33% and 82.52%, respectively, in the conditions of neutral pH and ambient temperature. Addition of PVP and PEG wetting agents improved the structural properties and permeability of membranes, but the dye removal was decreased as against plain ones. As the retention of PEG and PVP-based PSf and PES membrane was calculated at an average of 50%, they could be used for dye retention separately or could be a candidate as a pretreatment membrane prior to nanofiltration or reverse osmosis to make their lifetime longer.