Modified Polyethersulfone ultrafiltration membranes modified with citric acid crosslinked β-cyclodextrin for enhanced performance and azo dyes removal efficiency

Abstract Polyethersulfone (PES) polymer-based membranes with enhanced properties and performance were fabricated. A hydrophilic β-cyclodextrin (β-CD) crosslinked with citric acid (CA), was used as an additive and polyethylene glycol 400 (PEG 400) was used as the pore former. The membrane properties and performance were characterized using SEM, FT-IR, contact angle goniometer, SurPASS electro kinetic analyzer, dead end cell, and UV/Vis. Molecular weight cut off (MWCO) experiments, fouling studies, bovine serum albumin (BSA) and dyes (methylene blue, congo red and rhodamine B) rejection studies were also conducted. The results showed that addition of β-CD polymer improved properties and performance of the membranes. FTIR confirmed the presence of β-CD polymer in the membrane structure. SEM showed that increasing the ratio of β-CD influenced the structure of the membrane by reducing the presence of macrovoids while forming a spongy structure. The MWCO of the membranes ranged from 70 KDa to 92 KDa, classifying the membranes under ultrafiltration. Pure water flux and membrane performance increased with the increase of β-CD content. The best performing membrane with the highest β-CD polymer recorded a water flux 232.6 L.m-2.h-1 of at operating pressure of 2 bar and a flux recovery of 96.51 %. Furthermore, increasing β-CD polymer content decreased the contact angle from 78.60 to 57.81, which indicated an increase in membrane hydrophilicity. The maximum removal efficiencies of BSA, methylene blue, rhodamine B and congo red were found to be 100%, 80.32 %, 84.07 %, and 89.88 %, respectively. Evidently, β-CD improved the properties and performance of the PES membranes. β-CD can be utilized in improving hydrophilicity and antifouling properties of membranes. Moreover, β-CD enhance the application properties of PES membranes in removing dyes from water.