Deep eutectic solvent as novel additive for PES membrane with improved performance

Abstract For the first time, deep eutectic solvent (DES) is used as an efficient pore-forming additive to tailor the morphology and performance of polyethersulfone (PES) ultrafiltration (UF) membrane. The ultrafiltration experiments indicated that the water flux of membrane was significantly increased while the rejection ratio of membrane slightly increased by adding suitable amounts of synthesized DES (decanoic acid: N 4444 -Cl (2:1)) into the casting solution. When the concentration of DES was 2 wt%, the water flux of the membrane reached a maximum value of 142.84 L/(m 2 ·h), which was 4.65 times that of pure PES membrane. Meanwhile, the rejection ratios of pepsin, egg albumin and bovine serum albumin were as high as 91.5%, 97.3% and 99.0%, respectively. Moreover, the role of the DES in the formation process of PES membrane was investigated by viscosity measurement, scanning electron microscope (SEM), Fourier transform infrared spectra (FTIR), and thermogravimetric analyzer (TGA). It was concluded that component decanoic acid and component N 4444 -Cl in DES worked synergistically to improve membrane performance during the phase inversion process. Compared with other additives, the synthesized DES was a superior pore former. DES might provide new possibilities as the pore-forming agent for membrane formation.