Selective lithium extraction employing lithium manganese oxide-loaded polymeric membranes at natural brine pH and room temperature

EVA CAROLINA ARRUA; GISELLE BEDOGNI; CLAUDIO J SALOMON; VICTORIA FLEXER

DESALINATION

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2024

0011-9164

The current technology for lithium extraction from brines is recognized both for its techno-economic disadvantages and its environmental impacts. We have synthesized, characterized, and evaluated nanoparticles based on lithium manganese oxide towards selective lithium recovery from complex media. A solid-state synthesis and a hydrothermal method produced nanoparticles that showed diameters of 252.93 nm and 154.16 nm, respectively, both with very low polydispersity. 23.7 mgLi/gHMO and 30.7 mgLi/gHMO adsorption capacity values were obtained with solid-state synthetic and hydrothermal oxides. The hydrothermally synthesized nanoparticles were incorporated into polymeric membranes aiming at the development of a straightforward technological application. Membranes were prepared from polyacrylonitrile and polyethylene-glycol, and the affinity to lithium was once again evaluated. Membranes showed a high adsorption capacity for lithium (32.7 mgLi/gHMO) with almost identical kinetics and cyclability as the free nanoparticles in solution. An excellent selectivity for lithium was confirmed in experiments with a natural lithium-rich brine from the Lithium Triangle. All adsorption experiments were performed at neutral pH and room temperature. An undeniable advantage of membranes vs. nanoparticles is that the former does not require centrifugation after successful adsorption/desorption. These three characteristics are fundamental in the perspective of technology scale-up to minimize operational costs.