Water Softening Using a Light-Responsive, Spiropyran-Modified Nanofiltration Membrane.

A novel technique for the covalent attachment of a light-responsive spiropyran onto polyamide thin film composite nanofiltration (NF) membranes in a one-step reaction using low-energy electron beam technology is described. The effect of illumination of the immobilized spiropyran was studied, as well as the resulting membrane properties with respect to MgSO₄ retention, water permeability rate, and chlorine resistance. Electron beam irradiation showed a direct effect on the transformation of the rough PA NF membrane surface into a ridge-and-valley structure.

Charge Separating Microfiltration Membrane with pH-Dependent Selectivity.

Membrane filters are designed for selective separation of components from a mixture. While separation by size might be the most common approach, other characteristics like charge can also be used for separation as presented in this study. Here, a polyether sulfone membrane was modified to create a zwitterionic surface.