Preparation and adsorption performance of multi-morphology H1.6Mn1.6O4 for lithium extraction

In this paper, a lithium-ion sieve (LIS) with different morphologies, such as rod-like (LIS-R), spherical (LIS-S), flower-like (LIS-F), and three-dimensional macroporous-mesoporous (LIS-3D), was prepared by hydrothermal synthesis, solid reaction, and hard-template synthesis. The results showed that the LIS with different morphologies presented great differences in specific surface area, pore volume, adsorption selectivity, and structure stability. LIS-3D with highest specific surface area and pore volume displayed the maximum adsorption capacity and adsorption rate, but the stability of LIS-3D was poor because of the manganese dissolution. By comparison, LIS-S has the best structural stability while maintaining a satisfactory adsorption capacity (35.02 mg·g−1) and adsorption rate. The LIS-S remained about 90% of the original adsorption capacity after five cycles of adsorption–desorption process. In addition, in the simulated brine system (the magnesium to lithium ratio of 400), the LIS-S exhibited the highest selectivity (αLiMg) of 425.14. In sum, the LIS-S with good morphology is a potential adsorbent for lithium extraction from brine.