Highly selective membrane for efficient separation of environmental determinands: Enhanced molecular imprinting in polydopamine-embedded porous sleeve

Abstract

• Highly selective MIM was approached for efficient separation of determinand. • Dopamine-embedded porous sleeve was proposed for enhanced molecular imprinting. • Homogeneous imprinted sites spread throughout interpenetrating-bicontinuous porous. • Stable selectivity in regeneration cycles ensures the long-term availability. • Insight of polymerization mechanisms were obtained by DFT calculations. The molecularly imprinted membrane has shown irreplaceable superiority in advanced water treatment, biochemical purification, and in most cases, pretreatment of environmental determinands. However, effective and controllable construction of imprinted sites in membrane-based interpenetrating pores is as yet the significant bottleneck. Herein, we proposed a thermally induced strategy on the polydopamine-embedded molecularly imprinted membrane (DEMIM) for enhanced selective separation of Ciprofloxacin (CIP). The porous sleeve was constructed with polyvinylidene fluoride (PVDF), together with the integrated β-cyclodextrin (β-CD) for hydrophilicity and anti-fouling requirements. Based on the thermally induced operation, polydopamine (PDA) embedded in the membrane matrix acted as a secondary reaction platform, effectively improving the interpenetrating-bicontinuous porous morphology and enhancing the availability of imprinted sites in microchannels. The imprinting polymerization was carried out by the efficient thiol-ene Click reaction, which was investigated in depth by density functional theory (DFT) calculations. The impressive relative separation factor (2.33–4.59) and permselectivity (9.50–12.50) indicated the superior availability of DEMIM for the selective separation. The remarkable regeneration performance (fluctuation in 8.4%∼10.8%) demonstrated the feasibility of the porous membrane-based sleeve for regeneration of molecular imprinting. The approach and methodologies achieved in this work will potentially promote the development of novel molecularly imprinted membranes for advanced applications.