Improvement of water permeance and scaling resistance of nanofiltration membranes with Fe(III) - tannic acid modified MoS2 interlayer for drinking water treatment

Nanofiltration membranes (NFMs) are promising candidates for advanced drinking water treatment due to their excellent retention capabilities, however, their widespread application is limited by low water permeance and susceptibility to inorganic scaling. In this study, Fe(III)-tannic acid‑molybdenum disulfide (Fe(III)-TA-MoS 2 ) nanosheets were synthesized and employed as an interlayer material for NFM fabrication. The resulting NFMs were then created through interfacial polymerization, labeled as MoS 2 -1.5, MoS 2 -3.0, and MoS 2 -4.5 based on varying materials loading. Experimental results indicated that the membrane morphology, surface roughness, electronegativity, amine group content, hydrophilicity, selectivity, and resistance to inorganic scaling were all affected by the amount of Fe(III)-TA-MoS 2 loading. The MoS 2 -3.0 NFM exhibited the highest roughness and uniformity (Ra: 111.25 ± 3.30 nm), along with enhanced hydrophilicity and the smallest pore size (0.39 nm) among the Fe(III)-TA-MoS 2 NFMs. These characteristics contributed to a high water permeance of 20.19 LMH/bar. Sulfate rejection decreased notably with increasing amine content, while calcium ion rejection showed a slight decline as surface electronegativity increased. Notably, the pore size of the Fe(III)-TA-MoS 2 NFMs remained largely unchanged at low and moderate loadings. Although the MoS 2 -4.5 NFM exhibited even higher water permeance and electronegativity, its surface structure underwent significant changes, leading to inferior performance in terms of scaling resistance and natural organic matter removal compared to the MoS 2 -3.0 membrane. Overall, this study provides a novel strategy for enhance both water permeability and anti-scaling performance of NFMs, offering potential cost reductions for drinking water treatment applications.