In solving a scientific mystery, researchers from the University of Houston and the nation’s national laboratories also discovered a new avenue for clearing toxins from water, including wastewater produced by hydraulic fracturing.
The findings, described in a paper published this week in the Proceedings of the National Academy of Sciences, address the paradox of why the mineral barite – often laced with the chemical element strontium – is widely present in seawater.
Seawater is undersaturated with respect to barite, that is, the concentrations of barium and sulfate ions are too low to form barite precipitates, said Yandi Hu, assistant professor of civil and environmental engineering at the University of Houston and corresponding author on the paper. Strontium sulfate is much more water-soluble than barium sulfate, so thermodynamic levels of strontium in barium sulfate precipitates should be low, as well, she said.
But barite is often found in seawater, as is strontium-laced barite. Based on field-site findings that the presence of barite and high strontium levels in barite are associated with the presence of organic matter, she and colleagues began their study.
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Image: Yandi Hu, assistant professor of civil and environmental engineering at the University of Houston, led a team of researchers in developing a better understanding of the presence of strontium-rich barite in seawater. (Credit: University of Houston)