An evaluation of hydrogen peroxide-mediated hydroxylation of titanium-based ion sieves for enhancing the performance of lithium capture from aqueous solutions

The increasing lithium demand for use in energy storage and other industrial applications necessitates efficient recovery from low-grade aqueous resources, such as subsurface and surface brines. This study presents a novel hydrogen peroxide pretreatment strategy to create hydrogen titanate lithium-ion sieves with enhanced surface hydroxylation and improved selectivity for lithium recovery over commonly found brine inorganic constituents. The Li 2 TiO 3 precursor was hydrothermally treated with alkaline H 2 O 2 and subsequently acid-leached to yield the modified lithium-ion sieve (HP-HTO). Spectroscopic analysis confirmed a higher density of surface–OH groups on the HP-HTO surfaces. X-ray diffractograms revealed enhanced ordering of the (002) crystal plane, facilitating improved lithium-ion (Li + ) diffusion through the titanate layers. Consequently, HP-HTO exhibited over 20 % higher Li + uptake across the entire isotherm range, with a maximum of 61.02 mg Li + /g compared to 49.73 mg Li + /g for conventional H 2 TiO 3 . The Li + uptake follows Avrami kinetics and best-fitted using the Freundlich isotherm model, indicating surface heterogeneity and a distribution of binding energies, consistent with the structural nature of titanate materials. The effects of pH were examined in buffered systems to maintain a constant chemical driving force and eliminate the confounding influence of pH drop during Li + uptake. Selectivity studies were conducted in binary-ion and mixed-ion systems at equimolar concentrations of Li + , Na + , K + , and Ca 2+ to isolate competitive effects and better reflect true ion selectivity. Selectivity factors for Li + over individual competing cations demonstrated 24–161 % improvement with the hydrogen peroxide treatment. This is the first reported application of oxidative treatment in lithium-ion sieve synthesis. The facile peroxide treatment offers a scalable and efficient strategy for optimizing lithium-ion sieves for enhanced lithium extraction from complex brines.