pellets

Soda can hydrogen

August 15, 2025 By EarthWise Leave a Comment

Hydrogen is an ideal climate-friendly fuel because it doesn’t release carbon dioxide when it is used. But most hydrogen is produced in ways that result in significant carbon emissions. Thus, the search for green hydrogen goes on.

Last year, engineers at MIT developed a new process for making hydrogen that significantly reduces the carbon footprint of its production. The recipe uses seawater and recycled soda cans.

Pure aluminum reacts with water, breaking up the water molecules to produce aluminum oxide and pure hydrogen. But when aluminum is exposed to oxygen, it forms a shield-like layer that prevents the reaction.

The MIT researchers found that the shield can be removed by treating aluminum with a small amount of gallium-indium alloy. Mixing the pure aluminum with seawater not only produces hydrogen, but the salt in the seawater precipitates out the gallium-indium, making it available for reuse.

The research team carried out a “cradle-to-grave” life cycle assessment of the process, taking into account every step in using the hydrogen-production process at an industrial scale. They found that using recycled aluminum – chopped-up soda cans – is environmentally and economically superior to using “primary” aluminum, mined from the earth. The cans would be shredded into pellet and treated with the gallium-indium alloy. The pellets would be processed near a source of seawater where they would be combined to generate hydrogen on demand.

According to their analysis, the hydrogen produced would be at least competitive economically and environmentally with other potential methods of producing green hydrogen.

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Study shows making hydrogen with soda cans and seawater is scalable and sustainable

Photo, posted July 29, 2020, courtesy of Bruce Dupree via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Removing microplastics from water

April 23, 2025 By EarthWise Leave a Comment

Microplastics come from the breakdown of larger plastics in the environment as well as from direct use in various products such as certain cosmetics. They are found everywhere, from oceans and mountain peaks to the air and water, and alarmingly, in our bodies. They are ingested by all sorts of organisms, from tiny plankton to fish and marine mammals. Microplastics just don’t go away. They don’t biodegrade so they simply accumulate in the environment.

Researchers at North Carolina State University have recently demonstrated proof of concept for a system that actively removes microplastics from water. Such a system has the potential for helping to cleanse oceans and other bodies of water from the tiny plastic particles.

The system makes use of soft dendritic colloids, which are tiny particles that have the ability to stick to just about any surface. These sticky particles can attract microplastics and grab them, even in wet and salty conditions. The colloids are made from chitosan, a harmless and biodegradable polymer made from processed shellfish waste.

The researchers produced small pellets of the colloids that also contain small amounts of magnesium, which makes them bubble up and rise to the surface of water. The pellets are coated with a gelatin layer, which blocks the magnesium. As the gelatin gradually dissolves away, the pellets collect microplastics. Eventually, the result is a microplastic-laden scum that rises to the surface where it can be skimmed away.

The scum itself can be bioprocessed into more chitosan that can create more of these microcleaner pellets to then capture more microplastics. The researchers are investigating how the process can be scaled up to become a valuable tool in dealing with the microplastics problem.

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New Water Microcleaners Self-Disperse, Capture Microplastics and Float Up for Removal

Photo, posted January 17, 2018, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing methane from cattle

December 26, 2024 By EarthWise Leave a Comment

Livestock is responsible for almost 15% of global greenhouse gas emissions. Most of that is in the form of methane that cattle release when they burp. Grazing cattle produce more methane than feedlot cattle or dairy cows because they eat more fiber from grass. There are 9 million dairy cows in the U.S. but more than 64 million beef cattle.

Beef cattle spend most of their lives grazing in pastures and producing methane. Controlling the food of pasture-raised cattle is difficult because they often graze far from ranches for extended periods of time. During the winter and during times when grass is scarce, ranchers supplement the diet of cattle.

A new study by researchers at the University of California – Davis has found that feeding grazing cattle a seaweed supplement in pellet form reduced their methane emissions by nearly 40% without affecting their health or weight. There have been previous studies that showed seaweed cut methane emissions by 82% in feedlot cattle and over 50% in dairy cows. But this is the first study to test the effects of seaweed on grazing beef cattle.

The seaweed pellets were made available to grazing cattle and they ate the supplement voluntarily. Compared to a group of cattle who didn’t receive the supplements, the seaweed eaters had a 40% reduction in methane emissions.

Other research studies to reduce methane emissions using feed additives have taken place in controlled environments with daily supplements. This method provides a way to make a seaweed supplement easily available to grazing animals. It could even be introduced through a lick block for cattle.

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Feeding Grazing Cattle Seaweed Cuts Methane Emissions by Almost 40%

Photo, posted February 18, 2016, courtesy of Beverly Moseley/NRCS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing farm nutrient pollution

December 11, 2024 By EarthWise Leave a Comment

When farmers add nutrients to their fields in excess of their crops’ ability to utilize them, these excess nutrients can enter the surrounding environments and create environmental problems. The primary culprits are nitrogen and phosphorous. These fertilizer components emerge from fields and enter local waterways in surface runoff.

Researchers at the University of Illinois Urbana-Champaign have developed a form of designer biochar that can provide phosphorous in a time-released fashion and reduce the amount that escapes into the environment.

The researchers used sawdust and lime sludge, which are byproducts from milling and water treatment plants, respectively. They mixed the two ingredients and formed pellets which were then slow-burned in low-oxygen conditions to create phosphorous-laden designer biochar. Once the pellets bind all the phosphorous they can hold, they can be spread onto fields where the nutrient is slowly released over time.

They tested the pellets in working field conditions. The pellets are used to remove phosphorous from drainage water and then can be reused in the field to provide the nutrient to the plants.

The results were very encouraging. The biochar proved to be a very effective way to provide phosphorous to crops and then reduce how much phosphorous enters the environment. The cost of producing the biochar pellets was less than half that of alternative substances for phosphorous removal.

There is currently no regulation that requires farmers to remove phosphorous from drainage water but there are a growing number of conservation-minded farmers who want to reduce nitrogen and phosphorous losses from their fields. The idea that the recyclable pellets can both provide and control phosphorous is an attractive one.

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Scientists tackle farm nutrient pollution with sustainable, affordable designer biochar pellets

Photo, posted July 16, 2016, courtesy of Rick Obst via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Humans And Microplastics | Earth Wise

April 13, 2022 By EarthWise Leave a Comment

While plastic comes in all different shapes and sizes, those that are less than five millimeters in length are called microplastics. Primary sources of microplastics include microfibers from clothing, microbeads, and plastic pellets (known as nurdles). Secondary sources of microplastics come from larger plastic debris, like bottles and bags, that degrades into smaller bits over time.

Microplastic pollution can be found everywhere on earth, from the top of the tallest mountains to the bottom of the deepest oceans. Microplastics are in the food we eat, the water we drink, and the air we breathe.

According to research recently published in the journal Exposure & Health, humans ingest an average of five grams of plastic particles per week. This is roughly equivalent to the weight of a credit card. The plastic particles are trafficked in via food, such as seafood and salt in particular, as well as water. In fact, those who rely on plastic bottled water for their drinking needs ingest an additional 1,700 plastic particles each week.

Microplastics have also been detected in human blood for the first time. According to new research recently published in the journal Environment International, scientists detected microplastics in nearly 80% of the people they tested.

Half of the blood samples contained PET plastic, which is commonly used for drinking bottles. One third of the blood samples contained polystyrene plastic, which is often used for food packaging. One quarter of the blood samples contained polyethylene plastic, which is used to make things like shopping bags and detergent bottles.

With plastic production predicted to double by 2040, more research is urgently needed to understand how ingesting microplastics affects human health.

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Health risk due to micro- and nanoplastics in food

Microplastics found in human blood for first time

Discovery and quantification of plastic particle pollution in human blood

Photo, posted November 3, 2012, courtesy of Laura via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mercury In The Amazon Rainforest | Earth Wise

March 8, 2022 By EarthWise Leave a Comment

Recent research has found that some of the highest levels of mercury pollution ever recorded are in a patch of pristine Amazonian rainforest. The international team of researchers discovered that illegal goldmining in the Peruvian Amazon is the source of the pollution.

Illegal miners separate gold particles from river sediments using mercury. Mercury binds to gold, forming pellets large enough to be caught in a sieve. The pellets are then burned in open fire ovens, releasing the mercury to the atmosphere, leaving the gold behind. The mercury smoke ends up being washed into the soil by rainfall, deposited onto the surface of leaves, or directly absorbed into leaf tissues.

Deforested areas had low levels of mercury, while the areas with the largest, densest old-growth trees captured huge volumes of atmospheric mercury, more than any other ecosystem studied in the entire world. Mercury levels were directly related to leaf area index: the denser the canopy, the more mercury it holds. Birds from this area have up to twelve times more mercury in their systems than birds from less polluted areas. Such high concentrations of mercury could provoke a decline of up to 30% in these birds’ reproductive success.

Small-scale artisanal gold mining is an important livelihood for local communities. Eliminating it outright may not be a viable solution but coming up with ways to continue to provide a sustainable livelihood while protecting communities from poisonous pollution is essential.

In the meantime, the forests are doing an important service by capturing much of the mercury and preventing it from getting into the general atmosphere and endangering more people and animals. Burning or harvesting the mercury-ridden trees would release the mercury back into the atmosphere.

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Modern Day Gold Rush Turns Pristine Rainforests into Heavily Polluted Mercury Sinks

Photo, posted August 24, 2016, courtesy of Anna and Michal via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Threat From Nurdles

March 4, 2019 By EarthWise Leave a Comment

Just when we thought we knew all about the environmental threats caused by plastics, environmentalists have identified yet another problem. It is called a nurdle.

Nurdles are tiny pellets of plastic resin no bigger than a pencil eraser that manufacturers transform into packaging, plastic straws, water bottles and all the other things that are wreaking havoc on the environment.

It turns out that nurdles themselves are a problem because billions of them are lost from production and supply chains during handling, shipping and production every year, spilling or washing into waterways. There is limited information on the extent of this kind of plastic pollution and global researchers are still struggling to make an accurate assessment. A study last year estimated that 3 million to 36 million pellets escape every year from just one small industrial area in Sweden.

Eunomia, a British environmental consultancy, contends that nurdles are the second-largest source of microplastic pollution and estimated that the U.K. could be unwittingly losing billions of pellets into the environment every year.

New research is revealing the ubiquity of plastic pellets, from the bellies of fish caught in the South Pacific, to the digestive tracks of short-tailed albatross in the north and on the beaches of the Mediterranean.

A shareholder advocacy group called As You Sow has filed resolutions with Chevron, DowDupont, Exxon Mobil, and Phillips 66 asking them to disclose how many nurdles escape their production process each year and how they plan to address the issue. Several of the companies have responded with statements saying they are working to develop solutions that keep plastic out of our environment.

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There’s a Tiny Plastic Enemy Threatening the Planet’s Oceans

Photo, posted January 15, 2014, courtesy of Hillary Daniels via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Biomass: Renewable But Not Sustainable

July 23, 2018 By EarthWise 1 Comment

Biomass is often touted as a green energy source. Just recently, the US Environmental Protection Agency declared biomass energy to be carbon neutral – a policy already embraced by many European countries. However, burning forests for fuel has hard limitations and ecological consequences.