“Nanomagnet-inspired” design on molecularly imprinted nanofiber membrane: Mechanisms for improved transport selectivity of sufficient specific sites

Olive mill wastewater (OMW) is a major source of phenolic compounds (PCs) in the aquatic environment and terrestrial, growing concern over the health and environmental impacts of phenolic pollutants. Hereon, a “nanomagnet-inspired” molecularly imprinted nanofiber membranes (E-LMIMs) toward luteolin (LTL, a representative PC) were prepared by electrospinning method. Biosynthesized manganese nanoparticles (MnNPs, negatively charged) were uniformly blended in polyacrylonitrile (PAN) by electrostatic repulsion interaction. The -OH and -COOH groups on the surface of biomass MnNPs provided “signposts” for LTL to anchor at the designated sites during the imprinted polymerization, significantly improving the efficiency of imprinted sites. The positively charged chitosan (CS) was covered on nanofiber membranes to form a hydration layer for enhancing the high tensile strength and antifouling performance in extreme environments. The high matching effect of the MnNPs and the covalent/non-covalent interactions between rebinding sites and LTL greatly improved the transport selectivity. Isothermal and kinetic rebinding, permeation and transportation, and dynamic separation were investigated to propose the selective separation mechanism. As a consequence, optimized E-LMIMs with sufficient specific recognition sites contributed to greatly improving the selectivity coefficients (3.55 and 4.20), separation factors (4.04), and permselectivity coefficients (4.41 and 5.41). This study demonstrates that customized surface modification may serve as an effective approach for preparing high selectivity and permeability OMW treatment media.