This paper details the formulation and characterization of a novel nanoparticle system composed of polyethyleneimine (PEI) and dextran sulfate (DS) for direct lithium extraction (DLE) from bulk oilfield brines sourced from North America. Different mass ratios of solutions of PEI and DS at varied concentrations were prepared in the presence of 150-ppm lithium (Li) concentration to yield nanoparticle systems that entrap the Li ions in the solution electrostatically. Results indicated that the final pH, size, and charge of the nanoparticles were influenced by the mass ratio of PEI and DS. Integrating this innovative nanoparticle-based DLE method into existing lithium-treatment processes can enhance lithium recovery rates significantly.
Materials and Methods
Reagents. Polycationic branched PEI with a molecular weight of approximately 25 kDa was used without further purification. Anionic dextran sulfate—sodium salt with a molecular weight of approximately 500 kDa—was used as received.
