A dual regulation strategy for MXene-based composite membrane to achieve photocatalytic self-cleaning properties and multi-functional applications

Abstract

The development of two-dimensional (2D) membrane materials is limited by their relatively low antifouling performance. The high oxidation activity of photocatalytic technology can degrade the contaminants depositing on the membrane, which is expected to solve the problem of membrane fouling. Here, we reported a dual regulation strategy to construct a composite membrane, including chitosan modified MXene nanosheets as separation layer as well as g-C3N4 photocatalyst blended PVDF membrane as support layer. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) are used to verify the successful preparation of the dual interface composite membrane. Experimental results showed that the novel composite membrane exhibited high water permeability as well as achieved excellent rejection of anionic dyes and heavy metal ions (Congo red: over 98 % and Cr6+: 85.4%). Owing to photocatalytic activity, the composite membrane almost completely removed rhodamine B and tetracycline hydrochloride, and its self-cleaning ability improved the anti-fouling performance. Based on density functional theory, we further confirmed that the strong photocatalytic activity of the composite membrane was attributed to the efficient charge transfer between the photocatalytic support layer and the MXene separation layer. This work not only deepened the study of 2D-based materials in membrane preparation, but also provided a new dual regulation strategy to enhance multi-pollutants removal by composite membranes in wastewater treatment.