Double-layer-based molecularly imprinted membranes for template-dependent recognition and separation: An imitated core-shell-based synergistic integration design

Extensive efforts have been made for research on the development of selective separation membranes, however, the simultaneous promotion of stable selectivity and high permselectivity still faces its challenges. For the first time, a subversive synthesis strategy with hierarchical structure was proposed for the preparation of double-layer-based molecularly imprinted nanocomposite membranes (DLMIMs). Herein, the polydopamine (PDA) based imprinting process was initially performed on the surfaces of SiO 2 and activated carbon nanoparticles (ACNPs) to obtain the first PDA-based tetracycline (TC) imprinted layers. After a phase inversion process, a sol-gel polymerization procedure was then conducted for the preparation of second TC-imprinted layers. The TC-imprinted PDA-ACNPs/SiO 2 -based nanocomposite could be applied as the imprinting-initiated factors during the sol-gel TC-imprinted process, which led to the formation of imitated core-shell structure in the as-prepared blended membranes. Importantly, attributing to the as-synthesized double-layer-based TC-imprinted multilevel domains, abundant TC-recognition sites with high stability could be successfully synthesized in DLMIMs. Therefore, it was no surprise that large rebinding capacity (115.5 mg g −1 ), fast adsorption kinetics and high permselectivity coefficients (more than 6.5) were successfully achieved. The results of optimization experiments showed that the PDA-based TC-imprinted layer and sol-gel-based TC-imprinted layer would both cause for largely enhancing the rebinding capacity of DLMIMs. In addition, DLMIMs were synthesized without complicated procedures and the whole preparation process was feasible and pollution-free. Finally, we believed that the as-designed synthetic technique of DLMIMs would hold great potential in selective separation field.