Synthesis of aluminum-doped ion-sieve manganese oxides powders with enhanced adsorption performance

Manganese-Titanium Mixed Ion Sieves for the Selective Adsorption of Lithium Ions from an Artificial Salt Lake Brine

Lithium recovery is imperative to accommodate the increase in lithium demand. Salt lake brine contains a large amount of lithium and is one of the most important sources of lithium metal. In this study, Li₂CO₃, MnO₂, and TiO₂ particles were mixed, and the precursor of a manganese-titanium mixed ion sieve (M-T-LIS) was prepared by a high-temperature solid-phase method. M-T-LISs were obtained by DL-malic acid pickling. The adsorption experiment results noted single-layer chemical adsorption and maximum lithium adsorption of 32.32 mg/g. From the Brunauer-Emmett-Teller and scanning electron microscopy results, the M-T-LIS provided adsorption sites after DL-malic acid pickling. In addition, X-ray photoelectron spectroscopy and Fourier transform infrared results showed the ion exchange mechanism of the M-T-LIS adsorption. From the results of the Li⁺ desorption experiment and recoverability experiment, DL-malic acid was used to desorb Li⁺ from the M-T-LIS with a desorption rate of more than 90%. During the fifth cycle, the Li⁺ adsorption capacity of the M-T-LIS was more than 20 mg/g (25.90 mg/g), and the recovery efficiency was higher than 80% (81.42%). According to the selectivity experiment, the M-T-LIS had good selectivity for Li⁺ (adsorption capacity of 25.85 mg/g in the artificial salt lake brine), which indicates its good application potential.

Improved adsorption performance and magnetic recovery capability of Al–Fe co-doped lithium ion sieves

Al–Fe co-doped H1.6(Al0.3Mn0.7)1.6Fe0.1O4 lithium-ion sieves exhibit magnetic recovery properties and excellent recycling performance.

Extraction of Lithium from Single-Crystalline Lithium Manganese Oxide Nanotubes Using Ammonium Peroxodisulfate

In this work, a spinel single-crystalline Li_1.1Mn_1.9O₄ has been successfully synthesized using β-MnO₂ nanotubes as the self-sacrifice template. The tubular morphology was retained through solid-state reactions, attributed to a minimal structural reorganization from tetragonal β-MnO₂ to spinel Li_1.1Mn_1.9O₄. The materials were investigated as sorbents for lithium recovery from LiCl solutions, recycled using H₂SO₄ and (NH₄)₂S₂O₈. Li_1.1Mn_1.9O₄ nanotubes exhibited favorable lithium extraction behavior due to tubular nanostructure, single-crystalline nature, and high crystallinity. (NH₄)₂S₂O₈ eluent ensures the structural stability of Li_1.1Mn_1.9O₄ nanotube, registering a Li⁺ adsorption capacity of 39.21 mg g⁻¹ (∼89.73% of the theoretical capacity) with only 0.08% manganese dissolution after eight adsorption/desorption cycles, compared to that of 1.21% for H₂SO₄. It reveals the degradation of sorbent involves with the volume change, Mn reduction, and Li/Mn ratio depletion. New strategies, based on nanotube adsorbent and (NH₄)₂S₂O₈ eluent, can extract lithium ions at satisfactorily high degrees while effectively minimizing manganese dissolution.

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Single-crystalline Li_1.1Mn_1.9O₄ nanotubes were developed for lithium extraction

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The sorbent showed Li/Mn ratio depletion over adsorption/desorption processes

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Acid-free extraction minimized the structural change and Mn reduction

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Acid-free extraction improved the chemical stability and reusability of the sorbent