Preparation of polyethersulfone-based membrane containing ionic liquid and its application for removal of coomassie brilliant blue dye

The hydrophobic nature of most polymer membranes causes fouling and reduced permeability. Employing hydrophilic additives is one technique to minimize fouling and enhance membrane permeability. In this study, ionic liquid (IL) additive was employed for preparation of the nanofiltration membrane via phase-inversion method. The resulting IL w:as char:acterized using different methods such as 1H NMR and FT-IR. Nanofiltration membranes based on polyethersulfone (PES) containing IL additives at various weight percentages of 4, 4.5, 5, 6, and 7 wt.% were fabricated utilizing the phase-inversion method. Pure water flux test as well as separation of coomassie brilliant blue (CBB) with a concentration of 100 mg/L, were investigated. Flux measurement revealed that the membranes containing 5 wt.% of the IL  additive have the best surface qualitie, maximum pure water flux, and increased CBB separation. The net water flux of the membrane increased from 2.97 L/m2.h for the blank PES membrane to 33.63 L/m2.h for the PES/IL membrane with the additive content of 5 wt%. Based on the dye removal studies, all fabricated membranes rejected more than 94% of the dye solutions.