Photo-crosslinked nanofibers of poly(ether amine) (PEA) for the ultrafast separation of dyes through molecular filtration

Abstract

Molecular filtration is very attractive in the industrial applications of separation and water treatment, but it is challenging to realize fast separation due to the low transport rates and filtrate loss within the membranes in commercial ultrafiltration. We here demonstrated a novel example that a nanofiber membrane of poly(ether amine) (PEA) can be used in the separation of hydrophilic dyes through fast molecular filtration. Two types of PEA nanofiber membrane (PEA-NF) were fabricated through the electrospinning process, which were further photo-crosslinked through the UV-induced dimerization of coumarin groups. Regardless of their charge state, the obtained PEA-NF membranes exhibited strong adsorption to Ponceau S (PS), Rose Bengal (RB), Orange G (OG), Ponceau SX (PSX), and Bismarck brown Y (BY), and with weak adsorption to Methylene Blue trihydrate (MB), and Rhodamine 6G (R6G). Based on the unique selective adsorption to the hydrophilic dyes, PEA-NF membranes can separate mixtures of PS/MB in aqueous solution through molecular filtration with a very high flux rate of 2870 L m⁻² h⁻¹. In addition, the PEA-NF membranes are easily regenerated and keep the high separation efficiency over ten adsorption–washing cycles. The integration of the fast separation, easy regeneration and low-cost give PEA-NF membranes potential applications such as separation and water purification.