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Native plants and road salt pollution

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Applying salt to roadways lowers the freezing point of water and prevents slippery surfaces, which makes it safer for people to drive in wintry conditions.  In the U.S., more than 22 million tons of road salt is spread every year. 

But road salt harms infrastructure and the environment.   In fact, road salt damages cars and metal infrastructure by accelerating rust and corrosion.  Road salt can also leach into soil and waterways, disrupting ecosystems, degrading soil, contaminating water, and damaging vegetation. 

In cities and towns, road salts often wash into stormwater systems, posing health concerns and challenges for infrastructure.

A new study led by researchers from Virginia Tech looked at how salt affects plants and whether certain plants could mitigate salt pollution. The research team studied stormwater detention basins in Northern Virginia, examining the impacts of road salt on plants, soils, and water quality in green infrastructure systems.

The findings, which were recently published in the journal Science of the Total Environment, found that the amount of salt present in green infrastructure systems does reach levels that threaten plant communities.  However, the researchers found that relying on salt-tolerant plants for mitigation is unlikely to be effective because they simply don’t take in enough salt.

Certain plants, particularly cattails, absorbed substantial amounts of salt.  But even in a basin densely planted with salt-tolerant cattails, only up to 6% of the road salt applied during winter could be removed. 

Plants alone cannot solve our salt pollution problem.

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Researcher studies the power of native plants to combat road salt pollution

Photo, posted January 22, 2025, courtesy of the City of Greenville, North Carolina via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A better way to extract lithium

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Lithium is the critical component in the batteries that power phones and computers, electric cars, and the systems that store energy generated by solar and wind farms.  Lithium is not particularly rare, but it is difficult and often environmentally harmful to extract from where it is found.

Traditional ore sources are increasingly difficult and expensive to mine.  The largest known deposits of lithium are in natural brines – the salty water found in geothermal environments.  These brines also contain other ions like sodium, potassium, magnesium, and calcium, and efficiently separating out the lithium is extremely challenging.

Traditional separation techniques consume large amounts of energy and produce chemical waste, particularly hazardous chlorine gas.  These techniques typically suffer from poor selectivity; that is, the process is interfered with by the other ions present in natural brines.

A team of researchers at Rice University has developed a three-chamber electrochemical reactor that improves the selectivity and efficiency of lithium extraction from brines.  The middle chamber of the reactor contains a specialized membrane that acts as a barrier to chloride ions, preventing them from getting to the electrode area where they can form chlorine gas.

The new reactor has achieved a lithium purity rate of 97.5%, which means the setup can effectively separate lithium from other ions in the brine and allow the production of high-quality lithium hydroxide, the key material for battery manufacturing. 

The Rice University reactor design has the potential to be a game changer for lithium extraction from geothermal brines.

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‘Game changer’ in lithium extraction: Rice researchers develop novel electrochemical reactor

Photo, posted October 21, 2023, courtesy of Simaron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

New approaches to nuclear power

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The US is the world’s largest user of nuclear power.  Its 94 reactors supply nearly 19% of the country’s electricity. But the number of U.S. reactors has steadily fallen over the past 30 years and new nuclear power plants are a real rarity.  The reasons are a combination of perceived dangers following several nuclear accidents and the increasing costs associated with building plants that can meet a growing number of regulatory requirements.

There are recent developments associated with new advanced reactor technologies that may lead to a resurgence in the use of nuclear power.  Bill Gates’ energy company TerraPower is developing nuclear reactors that use sodium instead of water for cooling.  Such reactors operate at lower pressures and higher temperatures.  

Meanwhile, Kairos Power, a California-based energy company, has entered into an agreement with Google to build multiple small modular nuclear reactors that will supply electricity to that giant tech company.  The modular reactors use a molten-salt cooling system combined with a ceramic, pebble-type fuel in order to transport heat to a steam turbine to generate power.  The novel design of these reactors can reduce construction timelines, allow deployment in more places, and make final project delivery more predictable.

Surveys indicate that a majority of Americans favor the use of nuclear power, which has the advantages that it doesn’t create greenhouse gas emissions and can run 24-7.  But traditional nuclear power plants are too expensive and have too many potential problems.  These new nuclear power technologies may be the answer for allowing nuclear power to play an important role in the future energy system.

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New nuclear clean energy agreement with Kairos Power

Photo, posted May 16, 2016, courtesy of Steve Jurvetson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sodium-ion batteries

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The transition away from fossil fuels is driving a rapidly increasing need for batteries.  Both electric vehicles and energy storage for the electric grid are enormous consumers of batteries.  At present, lithium-ion batteries are almost universally used for these purposes.  They have been getting better all the time and cheaper all the time and are likely to be the answer for the foreseeable future.  But they are not perfect.

Lithium is only found in a relatively small number of places and mining and extracting it is fairly expensive and environmentally unfriendly.  Lithium-ion batteries also frequently contain cobalt, which has its own set of problems.  There are also safety issues related to the flammability of lithium-ion batteries. 

As a result, there continue to be numerous efforts to identify and develop alternative battery technologies.  One of these is sodium-ion batteries, which are similar in many ways to lithium-ion batteries but in which sodium replaces lithium as the cathode material.

Sodium is extremely common – it’s found in ordinary salt – and sodium-ion batteries have a high energy density and are easy to produce.  They should have a long lifetime and have a more benign environmental impact than lithium-ion.  Many companies and researchers are working on sodium-ion batteries and are making good progress.

A study by Chalmers University in Sweden looked at the potential for sodium-ion batteries and found that the batteries are particularly promising for use in energy storage even in their current state of development and could eventually be used in cars.  Whether sodium-ion batteries can be good enough and cheap enough quickly enough to give lithium-ion a run for its money remains to be seen.

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Resource-efficient and climate-friendly with sodium-ion batteries

Photo, posted March 12, 2013, courtesy of Chris Hunkeler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)