“Sandwich-like” electrospinning fiber-based molecularly imprinted membrane constructed with electrospun polyethyleneimine as the multifunction interlayer for the selective separation of shikimic acid

Electrospinning fiber with excellent structure is sharing the spotlight with molecularly imprinted membranes (MIMs) in the selective separation field. This work shows a teamed boronate affinity (TBA)-functionalized electrospinning fiber-based MIM with designed binding sites for shikimic acid (SA). Electrospun polyacrylonitrile (PAN) fiber is used as the supporting material. Specifically, polyethyleneimine (PEI)-PAN interlayer is constructed on the PAN substrate via electrospinning instead of chemical grafting. The role of PEI-PAN interlayer is compared with the PEI-grafting membrane as well as separation performance. The introduction of PEI via electrospinning enhances the adhesion between PAN substrate and imprinted layer, additionally, offers abundant reaction sites for more boronic acid moieties to decrease the pKa value of boronic acid. The "sandwich-like" SA molecular imprinted PAN membrane (S-MIPM) exhibits perfect integrity, excellent pore structure and enhanced selective adsorption performance. The adsorption amount of S-MIPM is 68.64 mg g−1 under neutral condition and 1413 L m−2h−1 bar−1 for the pure water flux. S-MIPM exhibits 3.1 times higher of adsorption capacity than that of the membrane prepared via chemical grafting, demonstrating the advantage of the proposed strategy. The membrane shows good selective permeation ability, which may give a better direction for the selective separation of 1,2-diols by boronate affinity.