Salt storage and induced crystallisation in porous asymmetric inorganic membranes

Weng Fu (1) , Julius Motuzas (1) , David Wang , Christelle Yacou , Anne Julbe (2) , James Vaughan (1) , João Diniz da Costa

1 UQ [All campuses : Brisbane, Dutton Park Gatton, Herston, St Lucia and other locations] - The University of Queensland
2 IEM - Institut Européen des membranes

Processing brines to recover strategic mineral salts using evaporation ponds requires large surface areas and are slow, even in arid climates. Here we show a novel membrane macropore storage mechanism that induces fast salt crystallisation in mesoporous top-layers in inorganic asymmetric membranes, stemming from 789 million nucleation points per metre square of surface area. During membrane pervaporation, dissolved salts are retained mainly in the macropores of the substrate which subsequently provide ideal conditions for crystal nucleation and growth on the membrane surface upon drying. This novel pore storage mechanism is attained owing to the solution flow modulation of the mesoporous titania and gamma-alumina layers that is counterbalanced by the flow of water during pervaporation. Therefore, pore size control is imperative to avoid flooding in the macroporous substrate. This work further shows the fundamental properties of the salt storage mechanism described by a single salt production coefficient, and a global salt production coefficient for metal chloride salts. This technology could potentially be considered for unlocking and process strategic global minerals from brines.

Mots clés: inorganic membranes; pore storage; pore size control; pervaporation; crystallisation

Domaines: Chimie; Sciences de l'ingénieur [physics]

Weng Fu, Julius Motuzas, David Wang, Christelle Yacou, Anne Julbe, et al.. Salt storage and induced crystallisation in porous asymmetric inorganic membranes. Journal of Membrane Science, 2022, 641, pp.119872. ⟨10.1016/j.memsci.2021.119872⟩. ⟨hal-03371555⟩