Construction of thin-film nanocomposite membranes by incorporating acyl chloride@MoS2 for enhanced nanofiltration performance

Incorporating suitable-sized nanoparticles into the organic phase of interfacial polymerization to form a nanomaterial-polyamide (PA) selective layer is a promising approach to enhancing membrane performance. In this work, we prepared novel thin-film nanocomposite (TFN) membranes by modifying the PA layer with acyl chloride@MoS2 nanoparticles. The nanoparticles added in the organic phase could obviously restrict the diffu-sion of piperazine monomers to the reaction zone during the interfacial polymerization process, demonstrated by both experiment results and molecular dynamics simulation. Compared to the thin-film composite (TFC) control membrane, the TFN membranes possessed a looser PA layer as well as a rougher and more hydrophilic surface with more negative charges, confirming the significant effects of the incorporated acyl chloride@MoS2 nano -particles on the PA layer formation. The optimal TFN membrane achieved a high Na2SO4 rejection of 98.6% and a satisfying water permeance of 27.1 L m- 2h-1 bar-1, over 2.9 times higher than that of the TFC membrane (9.3 L m- 2h-1 bar-1). Moreover, attributed to the chemical affinities (including covalent connection, hydrogen bonds, and electrostatic attraction) between acyl chloride groups of the nanoparticles and the PA matrix, the TFN membranes exhibited excellent long-term operation stability. The beneficial effect of grafting acyl chloride groups on the surface of MoS2 nanoparticles was verified by the more superior membrane performance enabled by acyl chloride@MoS2 than that achieved by original MoS2. This study offers a feasible strategy to improve the performance of TFN nanofiltration membranes by utilizing proper nanoparticles as organic phase additives.

Automated summary

Incorporating suitable-sized nanoparticles into the organic phase of interfacial polymerization can enhance membrane performance. In this study, novel thin-film nanocomposite (TFN) membranes were prepared by modifying the polyamide (PA) layer with acyl chloride@MoS2 nanoparticles. The added nanoparticles restricted the diffusion of piperazine monomers, resulting in a looser PA layer, a rougher and more hydrophilic surface, and improved membrane performance.