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

In this work, a spinel single-crystalline Li(1.1)Mn(1.9)O(4) has been successfully synthesized using β-MnO(2) nanotubes as the self-sacrifice template. The tubular morphology was retained through solid-state reactions, attributed to a minimal structural reorganization from tetragonal β-MnO(2) to spinel Li(1.1)Mn(1.9)O(4). The materials were investigated as sorbents for lithium recovery from LiCl solutions, recycled using H(2)SO(4) and (NH(4))(2)S(2)O(8). Li(1.1)Mn(1.9)O(4) nanotubes exhibited favorable lithium extraction behavior due to tubular nanostructure, single-crystalline nature, and high crystallinity. (NH(4))(2)S(2)O(8) eluent ensures the structural stability of Li(1.1)Mn(1.9)O(4) 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 H(2)SO(4). 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 (NH(4))(2)S(2)O(8) eluent, can extract lithium ions at satisfactorily high degrees while effectively minimizing manganese dissolution.