β-Cyclodextrin covalent organic framework modified-cellulose acetate membranes for enantioseparation of chiral drugs

• Published in: Separation and purification technology Vol. 285; p. 120336
• Main Authors: Luo, Huan, Bai, Xiaoping, Liu, Huixian, Qiu, Xin, Chen, Jianqiu, Ji, Yibing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2022
• Subjects: Chiral recognition mechanism; Enantioseparation; Mixed matrix membrane; Thin film nanocomposite membrane; β-cyclodextrin covalent organic framework; Mixed matrix membrane; Chiral recognition mechanism; β-cyclodextrin covalent organic framework; Enantioseparation; Thin film nanocomposite membrane
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2021.120336

[Display omitted] •β-CD COF membranes perform high permeability and high enantioselectivity.•β-CD COF membranes achieve enantioseparation for four chiral drugs.•β-CD COF contributes to improving membrane stability.•Molecular docking is applied to reveal the enantioseparation mechanism. Membrane-based chiral separation has attracted widespread research attention. However, traditional chiral membranes remain an unbridgeable trade-off between permeability and selectivity. Chiral covalent organic frameworks (CCOFs) with inherently high porosity and intrinsic chirality are highly promising solutions. Herein we report novel CCOF membranes for enantioseparation of chiral drugs. A β-cyclodextrin covalent organic framework (β-CD COF) was used as the chiral selector to fabricate two types of β-CD COF membranes by physically and chemically modifying cellulose acetate substrates, including a β-CD COF mixed matrix membrane (β-CD COF MMM) and a β-CD COF thin film nanocomposite membrane (β-CD COF TFN). In particular, the β-CD COF TFN was the first reported interfacial polymerized COF membrane for enantioseparation and performed more preferentially than β-CD COF MMM. The optimal enantioselectivities of d, l-tryptophan (e.e% = 100%), (RS)-mandelic acid (e.e% = 58.1%), d, l-phenylalanine (e.e% = 36.3%), and (RS)-propranolol (e.e% = 18.0%) and comparable solute flux (Flux = 1.9–5.4 nmol·cm−2·h−1) were achieved using β-CD COF TFN. Benefiting from the remarkable chemical stability of β-CD COF, such membranes also had excellent thermal stability, acid resistance, and long-term storage stability. Moreover, the chiral recognition mechanism was investigated using molecular docking simulations. Fabricated membranes with high enantioseparation performance and stability provide a new perspective on establishing chiral membranes and show potential for industrial application.