bromine

A green battery from industrial waste

February 11, 2025 By EarthWise Leave a Comment

Flow batteries are rechargeable batteries in which liquid electrolytes flow through one or more chemical cells from one or more tanks. The electrolytes are redox pairs, that is, chemical compounds that can reversibly undergo reduction and oxidation reactions. The most common redox electrolytes include elements like vanadium, chromium, iron, zinc, and bromine. Flow batteries can provide large amounts of both electrical power and stored energy based on the size of the electrolyte tanks. As a result, they can be scaled up far more readily than other battery technologies.

Flow batteries are safe, stable, long-lasting, and their electrolytes can easily be refilled. They have significant potential for use in utility-scale storage for renewable energy systems.

Researchers at Northwestern University have developed a redox flow battery based on an organic industrial-scale waste product. The material – triphenylphosphine oxide or TPPO – is produced in the thousands of tons each year. It is byproduct of producing a variety of substances including some vitamins, pharmaceuticals, agrochemicals, and other bulk chemicals. For the most part, TPPO is of little use and must be carefully discarded.

The current market for redox flow batteries is very small but is expected to grow over time as the need for utility-scale energy storage continues to expand. A battery technology based on a waste material that is already produced in high volume and that must otherwise be disposed of with caution would have significant advantages.

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Green battery discovery turns trash into treasure

Photo, posted January 12, 2015, courtesy of California Energy Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lithium in Arkansas

April 11, 2024 By EarthWise Leave a Comment

There are more and more electric cars on the road and utilities are installing record amounts of battery storage to back up solar and wind power generation. Both of these things currently use lithium-ion batteries so the need for them keeps growing.

There is actually plenty of lithium in the world. Sources of more than 100 million tons have been identified, which is enough to meet the projected needs for decades. But lithium is not easy, cheap, or environmentally friendly to extract. It is either blasted out of rocks that are then roasted at 2000-degree temperatures, or it is extracted from brine in places like the high Andes where it leaves behind toxic residues. Ramping up lithium production could greatly diminish the environmental benefits derived from green technologies.

A technique called direct lithium extraction, or DLE, may be a possible solution. The lithium is pulled out of brine while leaving other dissolved compounds behind. It is being tested in many places around the world and appears to offer the lowest negative impacts of available extraction technologies.

The Salton Sea area in California has rich deposits of lithium and is a good candidate for DLE. But conditions may be even better in Arkansas whose Smackover Formation is a brine-rich expanse of limestone.

The area was a productive oil field a hundred years ago and then undertook brine-processing in the 1950s to extract bromine. So, the area already has industrial infrastructure and no new land would need to be cleared.

The former oil fields of Arkansas may become an important domestic source of lithium.

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In Rush for Lithium, Miners Turn to the Oil Fields of Arkansas

Photo, posted February 26, 2021, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Safer Disposal Of Printed Circuit Boards | Earth Wise

March 4, 2020 By EarthWise Leave a Comment

Printed circuit boards are key elements of modern electronic devices that support and connect all of their electronic components. On average, they are composed of 30% metallic and 70% nonmetallic substances.

Once the circuit boards have served their purpose, they are often burned or buried in landfills, and can pollute the air, soil, and water. The biggest problem is that they have brominated flame retardants added to them in order to keep them from catching fire. Compounds in brominated flame retardants have been linked to endocrine disorders and fetal tissue damage.

Many circuit boards are recycled to recover valuable materials – generally the metals they contain. But recycling has its own problems. Metallic components can be recovered from crushed circuit boards by magnetic and high-voltage electrostatic separations. When the metals are removed, what remains are resins, reinforcing materials, brominated flame retardants, and other additives, which are of little value and present various dangers.

Researchers at Sun Yat-sen University in China have developed a ball-milling method to break down these potentially harmful compounds, enabling safe disposal. A ball mill is a rotating machine that uses small agate balls to grind up materials. The researchers also added iron powder, which helps remove bromine from organic compounds by breaking the carbon-bromine bonds in the flame retardants. The result was particles with half of their bromine content removed as well as decomposition of phenolic resin compounds.

The ever-increasing proliferation of device technology had led to a new set of pollution and waste challenges facing society. Research on ways to reduce the impact of high-tech garbage is an important need for society.

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Toward safer disposal of printed circuit boards

Photo, posted February 18, 2018, courtesy of Diego Torres Silvestre via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.