Novel Bio-Derived Nanocomposites Functionalized by 2D Materials for Enhancing Lithium Recovery from Aqueous Resources

Abstract

Lithium has emerged as a crucial element across the globe, with its center stage involvement in clean technology and electronics. Nevertheless, traditional methods of lithium extraction, which involve recrystallization, chemical precipitation, and mining, take their toll on energy consumption, the environment, and operational costs. Consequently, there is a pressing need for new, innovative, and sustainable extraction techniques from various aqueous sources, ranging from brine, wastewater, and seawater to geothermal fluids. This comprehensive research explores advanced materials and strategies for lithium recovery, focusing on nanocomposite-based materials. Initially, interfacial adsorption using sulfonated graphene oxide (SGO) and Ti₃C₂Tₓ MXene into alginate-based hydrogels showed spectacular lithium adsorptivity of 46 mg/g by synergistic ion exchange, chemisorption, and surface coordination mechanisms. These hydrogels showed regeneration stability and even enhanced selectivity when ionic liquid components were added, showing better performance compared to traditional adsorbents by favorably enhancing lithium separation from complicated saline solutions.
Building on this strategy, aerogel-based adsorbents made from modified sulfonated graphene oxide and carboxymethyl cellulose (SGO-CMC) exhibited outstanding lithium adsorptivity of 44.84 mg/g, chemical stability, and wide operation pH tolerance. Remarkably, the aerogel composition avoided the use of Ti₃C₂Tₓ MXene using cellulose, the most widely distributed naturally occurring polymer on the globe. This innovation gave analogous lithium adsorption efficiency and substantial cost savings compared to hydrogel-based routes, with enhanced environmental and financial sustainability for industrial scale applications. Standing on the shoulders of basic mechanisms proven on hydrogel-based separation schemes, membrane-based lithium separation was further enhanced by creating nanostructured lamellar membranes composed of stacked 2D SGO and MXene nanosheets. Fluidic experimental measurements verified that the membranes produce optimum Li⁺/Mg²⁺ ion selectivity due to inter-sheet interfacial spacing of SGO and MXene sheets, exhibiting efficient exclusion of larger divalent ions with selective lithium-ion transport facilitation.
Moreover, the research incorporated the use of computational screening (COSMO-RS) to develop innovative hydrophobic deep eutectic solvents (HDESs), specifically the TOPO:DecA (1:2) system, which surpassed 93% lithium extraction efficiency. Theoretical and experimental validation confirmed that the HDES had strong performance, scale-up capabilities, and suitability for real-world applications for extracting lithium from low-concentration aqueous streams. Subsequently, integrating the best performing HDES into previously optimized hydrogel and aerogel systems is expected to further enhance lithium selectivity, recalling successful prior work involving ionic liquids intand hydrogels. All these studies collectively adopt a comprehensive and multifaceted approach in recovering lithium by integrating new materials with computational design and integrating sustainable principles, which enhances the development of economically feasible and environmentally sustainable lithium extraction methods.

Date of Award	2025
Original language	American English
Supervisor	Faisal Almarzooqi (Supervisor)