Tunable dextran retention of MXene-TiO ₂ mesoporous membranes by adjusting the 2D MXene content

Abstract MXene-TiO ₂ mesoporous membranes on α -Al ₂ O ₃ hollow fiber supports are prepared and regulated by adjusting the two-dimensional (2D) MXene content. The prepared MXene-TiO ₂ membranes are characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and x-ray diffraction. The results show that TiO ₂ nanoparticles (NPs) are uniformed deposited on 2D platforms and that the 2D structure of the original MXenes is still preserved in the film after calcination, thereby successfully inhibiting sol infiltration into the porous support. The obtained MXene-TiO ₂ layer with a controllable thickness exhibits ‘ideal’ pathways (longitudinal-lateral transport nanochannel) for dextran molecules between the TiO ₂ NPs and MXene nanosheets. Furthermore, the MXene-TiO ₂ membranes show higher rejection performance of dextran with increasing 2D MXene content. The optimal mesoporous MXene-TiO ₂ hollow fiber membranes exhibit a cut-off molecular weight (MWCO) of 14 854 Da and a high pure water flux of 102 l m ⁻² h ⁻¹ per bar, thereby showing good potential as high-performance interlayers for ceramic nanofiltration membranes.