Reimagining membranes from the ground up

Conventional organic membrane technologies, typically used in purification and separation processes, tend to be energy-intensive, which results in considerable operational costs. Over time, these organic membranes also require regeneration, while the filtered components require further treatment — all of which equate to more expenses.

“Such limitations have driven us to reconsider membranes in terms of what they’re made of, how they’re structured and what they can do,” says Prof Ho. “Membranes play an integral, and often enabling role in many industrial processes. Enhancing their energy efficiency is what we can do to reduce the overall power consumption and, consequently, the carbon emissions associated with these processes.”

With this goal in mind, Prof Ho’s research team developed a technique for creating ultrathin, free-standing inorganic membranes. Crucially, these membranes can operate without the need for a supporting substrate — a big plus for their flexibility and functionality.

“Our method involves taming chaotic, free-floating, inorganic building blocks in a liquid environment, coaxing them to self-assemble into the desired membrane structure,” explains Dr Zhang Chen, a postdoctoral fellow in the team and first author of the study. “From a structural perspective, the membranes have more geometric diversity than their conventional counterparts — this means we can design them for specific, customised applications. Furthermore, unique membrane structures with diverse topologies have been fabricated, including those formed by mixing two particle types, continuous patchwork of non-mixing particle domains, and vertically stacked membranes.”