Ethylenediamine-β-cyclodextrin modified graphene oxide nanocomposite membranes for highly efficient chiral separation of tryptophan and propranolol enantiomers

The separation of racemic drugs remains significance and challenge for pharmaceutical production. Recently, chiral drugs permeation separation based on membrane is a promising technology with advantages of energy efficient, continuous operation and cost-effectiveness. Herein, ethylenediamine-β-cyclodextrin (EDA-β-CD) mixed matrix membranes (EDA-β-CD MMMs) and EDA-β-CD modified graphene oxide thin-film nanocomposite membranes (GO/EDA-β-CD TFNMs) were fabricated via precipitation phase inversion and interfacial polymerization process, respectively. The corresponding membrane structure and GO nanosheets were characterized by SEM, TEM, ATR FT-IR, EA. Subsequently, the water flux, BSA rejection and stability of the membranes were studied. Moreover, enantioseparation performances of GO/EDA-β-CD TFNMs and EDA-β-CD MMMs toward (DL)-tryptophan (Trp) and (RS)-propranolol (Prop) were examined. Results showed that the GO/EDA-β-CD TFNMs exhibited extraordinary enantioselectivity, which remained high percent enantiomeric excess (ee.%) of Trp (100.00%) and Prop (75.34%). GO nanosheets with a multilayer structure and an interlayer spacing not only provided bonding site of EDA-β-CD but also improved permeation flux of the membrane. Finally, molecular docking technology was used to study the separation mechanism of the membranes. These findings demonstrate that GO/EDA-β-CD TFNMs might possess possibilities of high permeability and high enantioselectivity for chiral drugs separation.