An urgent need exists for the development of advanced water purification technologies to meet the increasing global demand being placed on freshwater resources. Membrane-based separation technologies for size-selective contaminant removal represent a promising approach to achieve this goal. Here, a novel thin film composite nanofiltration membrane is prepared via interfacial polymerization of α-cyclodextrin on a commercially available polyacrylonitrile substrate. Subsequent in-situ inclusion complexation of alkyne-functionalized poly(ethylene glycol) (PEG) is then used to tune the polyrotaxane-based pores for size-dependent filtration. The resultant membrane shows excellent size-selective rejection rates for organic dye (e.g. rhodamine B, >99%) as well as heavy-metal ions (e.g. Co(II), >90%), while crucially maintaining high water permeance (e.g. H2O: 7.1 L h−1 m−2 bar−1). The facile and straightforward synthetic approach to the fabrication of polyrotaxane nanofiltration membranes, combined with their strong nanofiltration separation performance, holds significant promise for membrane-based water purification applications.
- Poly(ethylene glycol)
- Thin film composite membrane