Recent advances in membrane-based separations include chiral separations, nanofiltration, ion-permselectivity, gas separation and pervaporation. Novel chiral separations using enzymes and chiral surfactants as carrier have been achieved using facilitated-transport membranes. Graft-copolymeric membranes have been constructed that possess pH-controlled ion selectivity, and membranes have been made from gold nanotubules that exhibit electrochemically controlled permselectivity.