zinc

Stretchy And Washable Batteries | Earth Wise

January 13, 2022 By EarthWise Leave a Comment

Wearable electronic devices are a big market but there are limitations created by the properties of the batteries that operate them. The ideal battery for wearable electronics would be soft and comfortable, stretchable, and washable. Researchers at the University of British Columbia have recently developed just such a battery. The work has been described in a new paper published in Advanced Energy Materials.

The battery encompasses a number of engineering advances. Traditional batteries are made from hard materials encased in a rigid external shell. The UBC battery is stretchable because its key components are ground into small pieces and then embedded in a rubbery polymer. Ultra-thin layers of these materials are then encased in the same polymer. This construction creates an airtight, waterproof seal.

The batteries survived 39 cycles in washing machines using both home and commercial-grade appliances. The batteries came out intact and functional.

The batteries use zinc and manganese dioxide chemistry which is safer than lithium-ion batteries in case they break while being worn.

The materials used are low-cost, so if the technology is commercialized, it will be cheap. When it is ready for consumers, it is likely to cost no more than existing batteries. Work is underway to increase the power output of the batteries and their cycle life. There is already commercial interest in the technology.

There are many potential applications for such batteries. Apart from watches and medical monitors, they might also be integrated with clothing that can actively change color or temperature. If the batteries are commercialized, they will make wearable power comfortable, convenient, and resilient.

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Stretchy, washable battery brings wearable devices closer to reality

Photo, posted April 15, 2021, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Metals In Western Water Supplies | Earth Wise

October 29, 2021 By EarthWise Leave a Comment

A new study published by the University of Colorado Boulder looked at the problem of rivers being contaminated by acid rock drainage. Rocks that include sulfide-based minerals, such as pyrite, oxidize when exposed to air and water. The resulting chemical reaction produces sulfuric acid which, when present in water, dissolves metals like lead, cadmium, and zinc. The recent study found that rare earth elements are also leached out of rock by this process.

Rock drainage occurs naturally throughout the western United States, but historic mines that disturbed large amounts of rocks and soil have dramatically increased this process and have led to growing downstream water pollution. Upwards of forty percent of the headwaters of major rivers in the West are contaminated by some form of acid mine or rock drainage.

The warming climate has brought longer summers and less snow in winters. Longer, lower stream flows make it easier for metals to leach into watersheds and concentrate the metals that would otherwise be diluted by snowmelt.

Rare earth elements are essential components of many high-tech devices such as computers, hard drives, and cell phones. There is not a long history of studying the hazards they might represent when they enter the environment.

The study looked at the Snake River watershed in Colorado and found that increasing amounts of rare earth elements are entering Colorado water supplies. Concentrations of rare earth elements are not ordinarily monitored and there are no water quality standards set for them.

According to the researchers, once rare earth elements get into water, they tend to stay there. Traditional treatment processes don’t remove them. It is a growing problem that needs to be addressed.

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Rare earth elements and old mines spell trouble for Western water supplies

Photo, posted October 27, 2007, courtesy of Dion Gillard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Metal From Plants | Earth Wise

March 31, 2020 By EarthWise 2 Comments

Large amounts of metal in soil are generally bad for plants. But there are about 700 species of plants that thrive in metal-rich soils. These plants don’t just tolerate minerals from soil in their bodies but actually seem to hoard them to ridiculous levels.

In areas where soils are naturally rich in nickel, typically in the tropics and Mediterranean basin, plants have either died off or have adapted to become nickel loving. Slicing open a tree with this adaptation produces a neon blue-green sap that is actually one-quarter nickel, which is far more concentrated than the ore that typically feeds commercial nickel smelters.

A group of researchers from the University of Melbourne and other institutions is investigating whether this phenomenon is not just interesting but might also be of real commercial value. They established a plot of land in a rural village in Borneo and have been harvesting growth from nickel-hyper accumulating plants. Every six to twelve months, a farmer shaves off one foot of growth from these plants and either burns or squeezes the metal out. After a short purification, they end up with about 500 pounds of nickel citrate, potentially worth thousands of dollars on international markets.

Phytomining – extracting minerals from hyper-accumulating plants – cannot fully replace traditional mining techniques. But the technology could enable areas with toxic soils to be made productive and might allow mining companies to use plants to clean up their former mines and waste while actually collecting some revenue.

There are other plants that suck up cobalt, zinc, and similarly crucial metals. With growing demand for metals, perhaps it is time to harvest them on the farm.

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Down on the Farm That Harvests Metal From Plants

Photo courtesy of the University of Queensland.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Nutrients

August 15, 2019 By EarthWise Leave a Comment

Ending hunger isn’t a question of producing enough food. Globally, enough food is produced to feed all 7.7 billion people on the planet. But despite this, approximately 1 in 9 people go hungry. Conflict, natural disasters, and extreme poverty are some of the main drivers of global hunger.

Climate change is another. The more frequent and intense extreme weather events increase food insecurity and malnutrition by destroying land, livestock, crops, and food supplies. Climate change makes growing crops harder every year, especially for those who lack the tools and technology to adapt.

But the challenge of reducing hunger and malnutrition is to not only produce foods that provide enough calories, but to also produce foods that make enough necessary nutrients widely available. According to new research, climate change is projected to significantly reduce the availability of critical nutrients such as protein, iron, and zinc over the next 30 years. The total impact of climate change could reduce global per capita nutrient availability of protein, iron, and zinc by 19.5%, 14.4%, and 14.6%, respectively.

While higher levels of carbon dioxide can boost growth in plants, wheat, rice, corn, barley, potatoes, soybeans, and vegetables are all projected to suffer nutrient losses of about 3% on average by 2050 due to the elevated CO2 levels.

The study, which was co-authored by an international group of researchers and published in the peer-reviewed journal, Lancet Planetary Health, represents the most comprehensive synthesis of the impacts of climate change on the availability of nutrients in the global food supply to date.

Climate change is complicating the quest to end global hunger and malnutrition.

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Rising CO2, climate change projected to reduce availability of nutrients worldwide

Photo, posted April 30, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Better Zinc-Air Batteries

September 26, 2017 By EarthWise Leave a Comment

Zinc-air batteries are metal-air batteries powered by oxidizing zinc with the oxygen from the air. They have high energy densities (as much as five times more energy than lithium-ion batteries) and are more environmentally friendly. Since they are based on abundant zinc, they are potentially much cheaper to produce than the lithium-ion batteries that are used in so many current applications. But because it is difficult and expensive to produce rechargeable versions of these batteries, they have only found limited use in hearing aids, in some film cameras, and in large form to power navigation instruments, oceanographic experiments and railway signals.