Bioinspired Redox-Responsive Graphene Oxide Membrane Based on Supramolecular Host–Guest Interaction for Tunable Molecular Separation

Abstract

Intelligent and controllable water and molecule transport through a membrane is of crucial significance for broadening membrane applications in smart-gating filtration. Herein, inspired by the extensive redox reactions in living systems, we report a redox-responsive graphene oxide (GO) membrane assembled by introducing a supramolecular host−guest complex between ferrocene (Fc) and β-cyclodextrin (CD) into the interlayer of GO. The well-designed intelligent responsive membrane, which was composed of Fc-modified GO and CDmodified GO, possessed fascinating redox-response property. Utilizing the reversible deformation and restoration of the Fc/ CD complex, the size of the interlayer nanochannel between adjacent GO nanosheets was tunable by changing the membrane redox state. The water permeance and molecular separation performance of the membrane could be reversibly regulated with a high gating ratio (5.6) by virtue of the redox-responsive interlayer nanochannel. In addition, the obtained membrane also demonstrated superior cyclic response performance, excellent antifouling ability, and satisfactory stability in harsh environments. This work provides an innovative strategy for the fabrication of redox-responsive membranes, showing promising applications in intelligent and controllable gating and controllable water-contaminant removal process.

Recent advancements in supramolecular macrocycles for two-dimensional membranes for separations

“…68 Supramolecular macrocycles in 2D separation membranes are often charged by the nanosheet itself or by polar groups on the supermolecule host material. The electrostatic interactions between ions and the supramolecular 2D membranes can be used to separate charged substances, making this approach suitable for ions sieving, 69 enantiomer separation, 70 purification of dye wastewater, 71 among other applications. These separation processes are always impacted by charge effects ( e.g.…”

Surface Microstructure Drives Biofilm Formation and Biofouling of Graphene Oxide Membranes in Practical Water Treatment

“…This signified that tiny variations in the structures of GO membranes could trigger substantial biofouling. At present, most studies of GO membranes usually involve structure regulation during the fabrication process to optimize the membrane performance, − which will inevitably produce complex and diverse membrane surfaces, and thus are likely to induce the formation of different types of biofilms and unexpected biofouling when considering their practical applications. The investigation of the relationship between the structural properties of the GO membranes and biofilm formation, as well as the associated biofouling in real water environments, is essential for understanding biofilm formation and long-term antifouling mechanisms, biofouling control, and for providing guidance for the development of GO-based antibacterial/antibiofouling materials for specific environmental and biomedical applications, but relevant studies and mechanisms are rare and unclear.…”