Modified cellulose acetate ultrafiltration composite membranes for enhanced dye removal

A series of cellulose acetate (CA) ultrafiltration membrane blended with poly(acrylic acid) (PAA) and iron oxide (Fe₂O₃) was prepared by phase inversion technique. Fe₂O₃ was varied from 0-3 wt% in the casting solution composition to study its effect on the blend membranes. Prepared membranes were analyzed for their morphology, ultrafiltration (UF) features and dye rejection performance. Surface pore studies revealed the increase in the number of pores as well as pore size due to the addition of Fe₂O₃ to CA. Surface roughness was increased drastically for high concentration Fe₂O₃ composite membranes. Surface hydrophilicity was improved due to the addition of Fe₂O₃ in the composite membranes. Porosity measurements confirmed the enhanced porous nature of CA/PAA/Fe₂O₃ blend membranes than the pristine PES membrane. Pure water flux of the Fe₂O₃ composite membranes was improved to a maximum of four times as compared with pure PES membrane. Dye rejection studies revealed that the blend membranes had almost the same rejection as that of the pristine membrane with a largely enhanced flux rate. Results obtained clearly indicated the better performance of 1 wt% Fe₂O₃ blend membrane among the synthesized UF membranes.