Preparation of large layered MXene/Al(OH)3 composite membranes with porous structures and efficient separation performance

In this study, Ti3C2Tx layers with an average lateral size of approximately 8.3 μm were prepared. The LLM composite membranes synthesized from these layers not only possessed long and narrow mass transfer channels but also further prevented the generation of internal non-selective defects. Additionally, a strategy of compositing these Ti3C2Tx layers and Al(OH)3 was adopted. The strategy contributed to expanding the interlayer distances of the composite membranes and adjusting the in-plane stacking order, thereby facilitating the construction of mass transfer channels characterized by high permeance within the membranes. This resulted in the preparation of LLMA membranes. Among these LLMA membranes, the LLMA-1:7 composite membranes displayed outstanding performance in the sieving process. Their permeances were more than 10 times higher than those of the LLM membranes (with a thickness of 1 μm). Also, the rejection ratio for CV dye could even exceed 99 %, and the operational stability was also significantly improved. These advantages enabled them to avoid some of the shortcomings commonly found in two-dimensional (2D) separation membranes to a certain extent. In summary, the LLMA-1:7 composite membranes designed in this study demonstrated superior overall performance, compared to the majority of the previously reported 2D membranes. This research is expected to establish a solid foundation for the application of 2D MXene membranes in the field of water treatment.