Enhancing organic solvent nanofiltration performance and impeding aging of PTMSP membrane via incorporation of p-DCX and SDBS-MoS2

Solvent-resistant nanofiltration membranes, capable of breaking "trade-off" between permeability and selectivity while resisting physical aging, hold crucial utility in developing advanced membrane materials and reducing energy consumption associated with solvent recovery. Herein, the development of scalable, mixed matrix membranes (MMMs) was presented based on polysulfone (PSf) substrate with ultra-high permeability and aging resistance. The upper selective layer was composed of poly-trimethylsilylpropyne (PTMSP) and two types of nano-fillers, namely poly-dichloroxylene (p-DCX) and sodium dodecylbenzene sulfonate-molybdenum sulfide (SDBS-MoS2). Under the influence of the additives, the redistribution of the free volume of the polymer as well as the internal spaces within additives creates additional pathways for solvent diffusion, thus increasing solvent permeance. Additionally, the combined effect of the two additives is likely to inhibit filler agglomeration and improve the overall effectiveness of the additives. Compared to pure PTMSP membranes, the p-DCX/SDBS-MoS2 PTMSP MMMs exhibited enhanced methanol permeance (10.58 vs. 3.14 L m- 2 h-1 bar-1) and RB rejection (99.23 vs. 96.13 %), which greatly exceeded that of current OSN MMMs. As anticipated, aging of the prepared membranes decelerated with the addition of the additives, and the methanol permeation loss rate decreased from 50.32 % to 13.23 % after 300 h. Molecular dynamics simulations explored by structural analysis revealed the mechanism for the significant improvement in methanol permeance and aging resistance. The membranes obtained were found to be highly industrially applicable, thereby offering the potential to reduce operation costs in energy-intensive separation processes.