Polycations inclusion to simultaneously boost permeation and selectivity of two-dimensional TaS2 membranes for acid recovery

Two dimensional (2D) TaS 2 laminates have highly regular and ordered transfer mass channels, thus being promising acid recovery membrane candidates for diffusion dialysis (DD) applications to discern H + and metallic ions. However, it remains a daunting task to get access to high-performance 2D acid recycling membranes made from single TaS 2 nanosheets . Here, we report manipulation of the chemical environments of TaS 2 channels to develop excellent acid recycling 2D membranes. As demonstration projects, positively charged poly(diallyldimethylammonium chloride) (PDDA) and poly(4-vinylpyridine) (P4VP) in acid solution were chosen as polycation intercalators to modify the TaS 2 2D channels. Under the DD mode, the TaS 2 membrane exhibits a H + dialysis coefficient (U H + ) of 3.72 × 10 −3 m h −1 and separation factor (S) of 9 towards the simulated acid pickle. In contrast, the U H + and S value of the PDDA@TaS 2 membrane improve to 12.7 × 10 −3 m h −1 and 34.4 respectively. Those of the P4VP@TaS 2 membrane increase to 12.5 × 10 −3 m h −1 and 29.1 respectively. The reported acid recovery properties of PDDA@TaS 2 and P4VP@TaS 2 membranes exceed the commercial DF-120 acid recovery membranes. The experiment and simulation results reveal that the synergistical enhancements of U H + and S originate from the incorporating polycations in PDDA@TaS 2 and P4VP@TaS 2 composite channels.