A newly improved sorbent could offer an environmentally friendly way to get lithium from a relatively untapped resource in the U.S.: the brine produced by geothermal power plants (Environ. Sci. Technol. 2017, DOI: 10.1021/acs.est.7b03464). These plants pump hot water from deep geothermal deposits and use it to generate electricity, leaving behind a salty solution that can contain hundreds of parts per million lithium. Passing the brine through a sorbent that captures the lithium ions before pumping the brine back underground could collect the metal without the heavy environmental impacts of typical extraction methods.
Sorbents are a promising alternative for collecting lithium from sources where it is less abundant, like brines. The sorbent in the new study is made by intercalating aluminum hydroxide, or gibbsite, with lithium chloride to produce layers of [LiAl2(OH)6]+ with chloride ions and water in between them. Voids in the structure can fill with additional lithium ions, but …
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