Lithium recovery using a spinel-type hydrogen manganese oxide (HMO)–SBA-15 nanocomposite†

In today's economy, lithium is a crucial material, especially for electric vehicles (EVs) and renewable energy storage systems, which highlights the need for a more efficient and sustainable extraction method. There are well-established traditional methods such as brine evaporation and mineral processing, but they are time consuming, resource-intensive, and environmentally damaging. To address these issues, numerous methods have been proposed, and adsorption has emerged as a promising alternative. In this study, we report the development of a novel nanocomposite material (HMO-SBA15) synthesized via a straightforward and scalable route, starting from Santa Barbara amorphous (SBA) mesoporous silica and hydrogen manganese oxide (HMO), for the selective capture of lithium. HMO–SBA15 was synthesized by incorporating Li₄Mn₅O₁₂ into SBA15_calc, followed by H⁺ exchange to form a lithium ion-sieve (LIS) to capture lithium from an aqueous solution. The material was characterized by SEM, TEM, nitrogen adsorption–desorption analysis, FTIR, XRD, and TGA. Adsorption was evaluated under different conditions, namely pH, initial lithium concentrations, and contact time. The maximum adsorption capacity of 14.2 mg g⁻¹ was achieved after 6 hours at pH ∼ 7 and C₀ = 350 mg L⁻¹. Through kinetic and isotherm studies it was shown that the adsorption process followed a pseudo-second-order model, and the Langmuir isotherm best described the adsorption behavior, indicating monolayer adsorption. We demonstrated that the HMO–SBA15 composite has the potential to recover lithium from an aqueous solution and, with high surface area, structural stability, and operating at near-neutral pH, may be a sustainable and environmentally friendly alternative to traditional lithium extraction materials.