Efforts to remove aqueous lithium ion using Octolig® and methylated derivatives

ABSTRACT

Aqueous Li⁺ – containing samples (in DI water or well water) were eluted over Octolig®, a polyethylenediimine covalently attached to a high- surface-area silica gel, and only slight removal, if any, could be claimed. However, when using tetrahydrofuran (THF) as a solvent we quantitatively removed lithium ion with Octolig® or with alkylated Octolig®, demonstrating the efficacy of Octolig® and lack of advantage of a N, N′-dialkylated Octolig®. In addition, the removal of alkali metal ions (lithium, sodium, and potassium) in THF by Octolig® was partially selective: While being quantitative for lithium it was only about 40% for potassium. The study has potential implications for using geothermal brines not only as a heat source, but as a source of lithium as well.

KEYWORDS:

• Alkylation
• geothermal brines
• ion selectivity
• lithium removal
• Octolig®

Acknowledgments

We are grateful for the generous donation of Octolig® from Metre-General, Inc. We are also grateful to Mr. Ryan Jahn for selecting the analytical unit and to Dr. Wayne Guida, professor and chair, for authorizing its purchase. Rights to Octolig® were purchased by Frank Berry, President, Emden Environmental.