Reactive Epoxy Nanofiltration Membranes with Disulfide Bonds for the Separation of Multicomponent Chemical Mixtures

This article reports the fabrication of organic solvent nanofiltration membranes containing a labile disulfide bond, which is broken by reaction with a chemical stimulus. These membranes are a new generation of smart membranes that have tailored selectivities and flux that can be altered by reacting with a chemical stimulus. The selectivity and flux of chemicals through the membranes was controlled by varying the concentration of disulfide bonds in the membrane. When the disulfide bonds were cleaved, the pores in the membrane became larger and yielded different separation properties. The membrane selectivity was changed by up to 70% and flux was increased up to 5×. The rapid change in selectivity of the membrane allowed for the separation of three-component mixtures. A three-component mixture of 33.3% m-dinitrobenzene, 33.3% triphenylmethane, and 33.3% 1,3,5-tris(diphenylamino)benzene (TDAB) was separated into three different fractions that were significantly enriched in one of the three molecules. The first fraction contained m-dinitrobenzene at 82% purity and 84% yield, the second fraction contained triphenylmethane at 67% purity and 49% yield, and the third fraction contained TDAB at 71% purity and 88% yield.