Cation Controlled Properties of Vermiculite Membrane

Abstract

Hydrated ions at charged interface are ubiquitous and play a critical role in material’s surface properties. Vermiculite is one of the best examples of such a system. With high cation exchange and controllable swelling, vermiculite can be exfoliated into two dimensional (2D) nano-flakes and form free-standing membrane via self-assembly. In this work, we demonstrate how vermiculite membranes with different cation can be prepared. This approach enables us to intercalate specific cations into the free-standing vermiculite membranes, achieving tunable properties based on the cation species. By exploiting this mechanism, wetting properties of the vermiculite laminate can be adjusted from superhydrophilic to hydrophobic, thereby serving as a great candidate for fabricating microfiltration membranes to prevent fouling. In addition, the sub-micron vermiculite laminate is completely impermeable to gases, including helium, but allows permeation of relatively larger polar molecules such as water and ethanol. This unique selective semipermeable phenomenon is explained by presence of the interlayer cations which interacts preferably with the polar molecules. In this regard, our study lays a foundation for developing vermiculite-based membrane with tunable surface properties and selectivity for water purification and solvent separation applications.

Date of Award	31 Dec 2019
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Zhu Liu (Supervisor), Fabio Scenini (Supervisor) & Rahul Raveendran Nair (Supervisor)