Lignin-Based Hybrid Materials via Mechanochemistry for Sustainable Lithium Recovery from Geothermal Brines

The rapid growth in the use of Li-ion batteries in smartphones, laptops, portable electronic devices and electric vehicles has led to unmatched demand for lithium, making it essential to develop sustainable and efficient recovery strategies [1]. The exploitation of unconventional sources, such as geothermal brines, is attracting considerable attention; however, low lithium concentrations and the presence of competing ions hinder the selective extraction process. Against this backdrop, the development of hybrid materials as Li-adsorbents emerges as a promising approach to enhance selectivity, stability and process sustainability [2]. In this context, lignin-based hybrid systems offer a sustainable, circular solution by making use of an abundant waste biopolymer as a support and a functional component. In particular, this project focuses on the mechanochemical synthesis of lignin@MO materials, where MO is an oxygenated phase of a p- or d-block metal. Compared to conventional solution-based methods, the mechanochemical approach offers several advantages, including reduced reaction times, improved scalability and a lower environmental impact [3]. The resulting hybrid materials are expected to benefit from the interaction between the functional groups of lignin and the active sites of the metal oxides, which could enhance the adsorption of lithium in complex saline environments. Additionally, this strategy will exploit the potential of combining inorganic selectivity with biomass-derived functionality for the sustainable recovery of lithium. The proposed approach therefore aims to design hybrid systems by combining lignin with established and emerging inorganic adsorbents for scalable and low-impact applications. [1] Hou, J., et al., Advanced Functional Materials, 2021, 31 (46), 2105991. [2] Zhang, B., et al., Energies 2025, 18 (12), 3146. [3] Pagola, S., Crystals 2023, 13 (1), 124.