Сорбенти на основі оксидів мангану для селективного видалення іонів літію

• Date: 2025
• Main Authors: Kotynska, L. Y., Holdynsky, M., Fedoryshin, O. S., Zakutevsky, O. I., Romanova, I. V.
• Format: Article
• Language: English
• Published: Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2025
• Subjects: вилучення іонів літію; оксиди мангану; ·наноструктуровані матеріали; вплив методу синтезу
• Online Access: https://www.cpts.com.ua/index.php/cpts/article/view/779
• Journal Title: Chemistry, Physics and Technology of Surface

Two manganese oxide-based adsorbents were synthesized using a precipitation method followed by hydrothermal treatment of reagents. The templating method was employed to create the sorbents’ selectivity, ensuring efficient extraction of lithium ions from precursors using HCl solution. Physico-chemical properties of the synthesized samples were compared using methods of X-ray diffraction (XRD), low-temperature nitrogen adsorption/desorption analysis, and scanning electron microscopy (SEM) coupled with an energy dispersive X-ray system. XRD and EDS analyses revealed that the sample synthesized via single-step precipitation method consisted of a single pyrolusite phase (MnO2), whereas using the prior oxidation step resulted in material with a spinel structure. SEM images shown a nanoscale morphology both of the materials obtained, the first sample comprised nanorods with an average diameter of 35–90 nm, while the second sample consisted of spherical hollow particles ranging from 30 to 60 nm in diameter.  Porosity studies fixed mesopores with radii ranging from approximately 1.5 to 10 nm in all materials, sample with the spinel structure had the largest surface area, total pore volume, and a higher quantity of mesopores in the 1.5–3 nm range. It was defined this sample demonstrated a lithium ion uptake of 4.6 mmol/g (31.7 mg/g) from aqueous solutions, with minimal decrease observed in supporting electrolytes. The calculated removal efficiency for this material was reached 100 % at low concentrations of lithium ions (< 0.7 mmol/L) and it was fixed the good selectivity in adsorption from artificial seawater. The best conditions for the precipitation method were found, involving prior oxidation to manganese(III) oxide.