Scientists in Germany recently published a study in which they took a new approach to analyzing nanofiltration membranes. They used a methodology called “Thinking in terms of Structure-Activity-Relationships” (AKA T-SAR) that was first introduced in 2003 to determine the properties and the effects of different substance classes on biological systems. T-SAR was applied here to see if it could provide them with a better understanding of the NF membrane as well as predict the membrane’s performance for the recovery of ionic fluids.
T-SAR analysis makes it possible to analyze a chemical compound using only its three-dimensional chemical structure, but the process is made more difficult and complex as the size of the molecule increases. This characteristic of T-SAR creates a problem for NF materials. In order to overcome it, the researchers combined T-SAR methods with traditional membrane characterization procedures to gather more conclusive evidence on the importance of chemical structure for separation performance. The algorithm to conduct the T-SAR analysis of a chemical compound includes 17 steps in the areas of: Chemical Structure, Stereochemistry, Molecular Interaction Potentials, and Reactivity.
T-SAR Description
The Components of T-SAR Analysis (Click to Make Larger)

The materials involved for this experiment included two NF polyamide membranes (FilmTec NF-90 and NF-270) and three ionic liquids. In order to prep these membranes for T-SAR analysis, they were first subjected to some baseline analysis such as confirming their composition through spectroscopy and determining their pure water capability with an HP4750 stirred cell. The ionic fluids were tempered with deionized water to reduce the influence of additional ions and then cycled through the HP4750 to make samples of the feed, retentate, and permeate for ion-chromatography analysis.
After this preparation and traditional analysis, the materials were then subject to the full T-SAR analysis procedure to determine if it really can be used to understand NF membranes and predict their performance. You’ll have to look at the full report for all of the detailed results of the T-SAR analysis.
After all this work, the authors concluded that, “the experimental values obtained for the filtration of such ionic liquids are in good agreement with the predictions.” So it looks like T-SAR methodology might be used more often in NF membrane experiments! Sehr gut!
Read the complete report here.