Simultaneously enhanced permeability and anti-fouling performance of polyethersulfone ultrafiltration membranes by structural control and mixed carbon quantum dots

Assisted with a direct current (DC) electric field membrane forming device, the Polyethersulfone (PES) ultra filtration (UF) membrane was fabricated by non solvent induced phase inversion method. The membrane morphology and performance were simultaneously changed because the PES polymer chains were polarized by the DC electric field. As a result, the M-0-DC membrane showed a porous and thinner separation layer structure with a water permeability of 280.1 L m-(2) h(-1).bar(-1), which is similar to 55% higher than that of M-0. Further, a novel antifouling PES membrane containing carbon quantum dots (CQDs) with a concentration of 0.5 was prepared combined with the electric field. The water permeability (similar to 164% higher than M - 0) of M-0.5-DC was substantially improved and the rejection rate for BSA was 98.4%. The M-0.5-DC also exhibited excellent antifouling property, that is, its BSA flux recovery rate reached as high as 95.3%. Apart from, the Congo red self-cleaning ability investigation of M-0.5-DC showed that the membrane became clean again after the irradiation of ultraviolet light for 2 h. The simultaneously enhanced water permeability and improved anti-fouling property by DC electric field and CQDs are promising advances that may promote the applications of UF membranes in water treatment.