LITHIUM EXTRACTION FROM OILFIELD BRINES
North America has vast petroleum hydrocarbon reserves, and nearly a million producing oil and gas wells. A byproduct of this production is wastewater brines, which contain considerable concentrations of valuable metals, including lithium. Lithium is traditionally used in the manufacture of glass, ceramics, and lubricants, and increasingly in lithium ion batteries (LIB). With the continued growth of the LIB market, the extraction of lithium from oilfield brines is a potentially promising new industry.
The Alessi group is developing novel methods of extracting lithium from brines that can exceed 200,000 parts per million in total dissolved solids. A novel metal oxide sorbent developed in this research program is routinely yielding >95% extraction efficiency, with little co-extraction of other metals.
Pyrogenic Carbon
Pyrogenic carbon is essentially charcoal - a solid byproduct created by the heating wastes as by-product (farming, oil and gas production, etc.) in an oxygen-limited environment. As a stable, high surface area, carbon-rich product, they can be effective in the removal of a wide range organics and metals, including chlorinated ethenes, PAHs, and other hydrophobic organic contaminants, from water. Char is also produced naturally as the product of forest fires.
Our work investigates the surface reactivity and metal adsorption mechanisms of pyrogenic carbon, focusing (1) on the role of wildfire in mobilizing metals and nutrients now and in the geologic past, and (2) the production, reactivity, and toxicity of carbonaceous nanoparticles derived from pyrogenic carbon.
FE(II)-BEARING MATERIALS
X-ray absorption spectra showing the redox transformation of Cr(VI) on nanomaghemite (Komárek et al., 2015).
Iron-bearing minerals can control the adsorption, precipitation, and redox transformations of trace metals in aquifers, soils, and the ocean. In many environments, nanoparticulate iron phases form as precursors to well-ordered minerals, which may be far more soluble and reactive toward trace metals. We are exploring the thermodynamics and reactivity of freshly-precipitated green rusts, solid phases important in both reducing terrestrial environments and in the chemistry of the early oceans. In a second line of research, we are exploring the doping of biochar with iron to increase its electrical conductivity, thereby enhancing its ability to immobilize certain redox-active metals, such as hexavalent chromium in contaminated waters.