Two-dimensional materials in enhancement of membrane-based lithium recovery from metallic-ions-rich wastewaters: A review

The ubiquitous use and continuously growing demand for lithium (Li) in transportation and high-technology products have rendered Li+ recovery imperative for sustainable growth. Recently, particular emphasis has been placed on two-dimensional (2D) materials-based membranes due to their superior characteristics compared to ceramic or polymer membranes. This review focuses on the state-of-the-art progress in exploiting applications of newly-developed 2D nanomaterials in selective lithium recovery via membrane-based technology and design of filtration membranes, including selectivity improvement and adding new favorable functionalities like antibacterial, antifouling, and hydrophobicity. From the viewpoint of application, advances in selectivity enhancement via 2D materials, role of these materials as fillers, their benefits, separation, and the transport mechanism of each group are critically assessed, and their drawbacks and prospects of each classification are discussed in detail. In addition to the compendium of basics and reasons behind each ion separation route, experimental outcomes reported in the literature have been comprehensively summarized. Finally, future opportunities for lithium are highlighted to inspire subsequent research.