A membrane fitted with spinning turnstiles moves water 44% faster — and separates it ten times more precisely

Filters that separate one molecule from another face a stubborn trade-off: push molecules through faster and the sorting gets sloppier. A University of Queensland team led by chemical engineer Xiwang Zhang looked inside the filter itself, at channels less than a nanometre wide — about 100,000 times thinner than a human hair — and lined them with ammonium ions that keep rotating on their own. Like turnstiles in a busy station, the spinning ions keep traffic moving while still checking who gets through. In tests separating ethanol from water, reported in Science, the new membrane moved water about 44% faster, cut the ethanol slipping through by 90%, and sorted ten times more accurately than a standard membrane. If it scales up, the approach could cut the energy used in purifying chemicals, recovering valuable resources and making sustainable fuels.

SDG 9 · Industry, innovation and infrastructure — Mechanism: tech innovation