Constructing imprinted reticular structure in molecularly imprinted hybrid membranes for highly selective separation of acteoside

Acteoside (ACT) is an active component of Cistanche tubulosa with rare content and complex structure. The development of ACT-based molecularly imprinted hybrid membranes (A-MIHMs) with high rebinding capabilities and selectivity remains a challenge to obtain high purity of ACT. Here a series of A-MIHMs was designed for highly selective separation of ACT. The A-MIHMs were fabricated by incorporating imprinted nanofillers made of ACT-imprinted surface molecularly imprinted polymers and polyethylenimine modified mesoporous silica (SMIP-PEI/MCM-41) into polyvinylidene fluoride (PVDF) powders. The as-prepared optimum A-MIHMs-400 exhibited the highest rebinding capabilities of 96.24 mg/g, an excellent rebinding selectivity of 4.48, and permselectivity of 6.37 for the ACT. The following reasons were attributed to the results: first, the incorporated SMIP-PEI/MCM-41 nanofillers were distributed homogeneously into the A-MIHMs, and the pores of the membrane were tailored to form the interconnected imprinted reticular structure, and it can capture abundant ACT, resulting in highly selective separation of ACT. Second, the formed imprinted cavities and sites on the imprinted reticular structure can uniquely recognize ACT, enhancing A-MIHMs selectivity for ACT. Third, the amino groups of PEI acted as affinity sites with a high-affinity for the hydrophilic molecule of ACT, allowing A-MIHMs to bind the ACT with high rebinding capabilities and selectivity. After eight cycles, the regeneration rate approached 90%, indicating that A-MIHMs were highly renewable. The design of MIHMs with an imprinted reticular structure would provide a new strategy for the highly selective separation of active components from natural products.