Quantitative assessment of structure-performance relationship of loose nanofiltration membranes with TA-MoS2 interlayer for effective dye/salt separation

Abstract

The novel strategy of thin-film nanocomposite loose nanofiltration (LNF) membranes incorporating an interlayer of nanomaterials has raised growing interests for the high-performance membrane design. Although the effects of membrane structure on separation performance have been elucidated for a long time, however, the quantitative structure-performance relationship of interlayer-based LNF membranes has not been established. In this study, we established the structure-performance relationship of TA-MoS₂ interlayer based LNF membranes from a quantitative level for the first time. The correlation heat map analysis identified four key structural parameters (e.g. selective layer thickness, crosslinking degree, water contact angle, and zeta potential) for water permeability as well as dye rejection, and three key structural parameters (e.g. selective layer thickness, crosslinking degree, and zeta potential) for salts rejection, respectively. Furthermore, the multiple linear regression analysis revealed the rigorous mathematic modeling of key structural parameters-separation performance relationships with all R² values above 0.899, and determined the contributions of each key structural parameter to the separation performance in a quantitative level. Finally, the optimal TA-MoS₂ interlayer based LNF membrane exhibited a high water permeability of 80.2 LMH·bar⁻¹, effective separation of dye/salts (rejection rate: congo red (99.0%), methyl blue (95.1%), Na₂SO₄ (1.5%) and NaCl (0.5%)), good stability and antifouling properties (i.e. water flux recovery rate (FRR) of 96% for humic acid). This study can pave the way of quantitatively design of interlayer-based LNF membrane with targeted performance.