Papers by Keyword: Ion Sieve

Abstract: This paper chose LiMn2O4 as ion-sieve. In the ion-sieve precursor pickling experiment, the elution effects of hydrochloride, nitric acid and sulfate were compared and hydrochloride was proved the suitable eluent. By changing the acidity of pickling time, the lithium evacuation rate and the manganese solution loss rate basically achieved balance after pickling for 5 h. The static adsorption experiment suggested that when the pH was 12.5 and adsorption time was 30 h, the equilibrium adsorption capacity was 19.71 mg/g.

Abstract: To meet increasing demand for lithium, it is very essential for exploiting the lithium resources dissolved in seawater, groundwater and brine. It’s prospected that extracting lithium from solution with lithium ion-sieve, that is, spinel lithium magnesium oxides. Preparing high effective lithium ion-sieve is the heart of the technology. Magnesium oxide (MnOOH), the precursor (Li1.6Mn1.6O4) and the lithium ion-sieve were prepared successively, and their structure and properties were characterized with AAS, XRD and SEM. The results show that fibrous MnOOH is synthesized via hydrothermal reaction of KMnO4 and ethanol at 120°C for 24 h, and brown Li1.6Mn1.6O4 with little impurity is prepared with the Li/Mn mole ratio 4 after hydrothermal reaction of MnOOH and 4 mol/L LiOH at 120°C for 24 h and roast 4 h at 400°C, then lithium ion-sieve is obtained after washing 24 h with 0.5 mol/L HCl solutions and its adsorption capacity for Li+ reaches 38.26 mg/g, which has considerable potentiality comparing to its theory value. All these suggested that synthesis of single phase Li1.6Mn1.6O4 should be essential for next study on extraction lithium with lithium ion-sieve from seawater, groundwater and brine.

Abstract: Mesoporous titania nanoribbons are synthesized via an optimized soft hydrothermal process and the derived titania ion-sieves with lithium selective adsorption property are accordingly prepared via a simple solid-phase reaction between Li2CO3 and TiO2 nanomaterials followed by the acid treatment process to extract lithium from the Li2TiO3 ternary oxide precursors. The physical chemistry structure are characterized by XRD, TEM/HRTEM, SAED and N2 adsorption-desorption analysis; and the lithium selective adsorption properties are tested by the adsorption isotherm measurement and demonstrated with the distribution coefficient of a series of alkaline and alkaline-earth metal ions. Though the high temperature calcinations and lithium insertion-extraction process resulted in the agglomeration of nanostructure to large bulky particles, it implied that that the low-dimensional titania nanoribbons might be functionalized to lithium ion-sieves with remarkable adsorption capacity and selectivity, promising in the utilization of lithium extraction from aqueous resources including brine or seawater.

Abstract: Ion-sieve type manganese oxide spinels for the selective adsorption of lithium(Li) from seawater were prepared and their properties were examined. LiM0.5Mn1.5O4 (M=Mg, Zn) precursors, in which part of manganese(Mn) was substituted with magnesium(Mg) or zinc(Zn), were synthesized through the solid-state reaction. The adsorbents, HM0.5Mn1.5O4 (M=Mg, Zn) were derived from LiM0.5Mn1.5O4 (M=Mg, Zn) by acid treatment. The optimum acid treatment was obtained at hydrochloric acid concentration of 0.5M and 0.3M for LiMg0.5Mn1.5O4 and LiZn0.5Mn1.5O4 precursors, respectively. Both cases required thrice-conducted acid treatments for the best results. The adsorption of Li by HMg0.5Mn1.5O4 and HZn0.5Mn1.5O4 adsorbents followed the Freundlich equation and the maximum adsorption of Li in artificial seawater was 30.3 mg/g and 33.1 mg/g, respectively. The adsorption efficiency of Li by HMg0.5Mn1.5O4 and HZn0.5Mn1.5O4 adsorbents in artificial seawater, in which Li concentration was adjusted to 0.2 mg/L, was as high as 88% and 89%.

Abstract: Adsorbing and salvaging extremely small quantities of lithium ion, high-performance ion-exchange type lithium ion adsorbent was prepared through the ion-sieve formation method. The method uses acid treatment after the synthesis of spinel-structured nano-Li_1.33Mn_1.67O₄ precursor through the tartaric acid gel process. It has good selectivity and high efficiency in adsorbing lithium ion in seawater. The generated adsorbent showed a 28.2 mg/g lithium uptake from artificial seawater. This adsorbent further showed a difference reproducibility that was lower than 10% when subjected to five cycles of adsorption and desorption experiments.