Earth Wise

A look at our changing environment.

You are here: Home / Archives for capture

capture

Removing microplastics from water

By 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.

**********

Web Links

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

A new way to help purify water

By Leave a Comment

Engineers at the University of Michigan and Rice University have developed a new technology for removing boron from seawater, an important step in turning seawater into safe drinking water.

Boron is a natural component of seawater that remains a toxic contaminant in drinking water after conventional filters remove salts from seawater.  The boron levels in seawater are about twice as high as the World Health Organization’s most lenient limits for safe drinking water and 5 to 12 times higher than what many agricultural plants can tolerate.

Boron passes through the reverse osmosis membranes used in desalination plants in the form of boric acid.  To remove it, the desalination plants normally add a base to the treated water that causes the boric acid to become negatively charged.  An additional membrane then removes the charged boron, and an acid is then added to neutralize the water.  All of this is expensive and complicated.

The new technology uses electrodes that remove boron by trapping it inside pores studded with oxygen-containing structures that bind with boron but let other ions pass through.  Capturing boron with electrodes enables treatment plants to avoid the need for a second stage of reverse osmosis.

Global desalination capacity reached 95 million cubic meters a day in 2019.  The new membranes could save nearly $7 billion a year.  Such savings could make seawater a more accessible source of drinking water for a thirsty world.  Freshwater supplies are expected to meet only 40% of the world’s demand by 2030.

**********

Web Links

New water purification technology helps turn seawater into drinking water without tons of chemicals

Photo, posted August 21, 2018, courtesy of Alachua County via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Engineering plants to consume more carbon dioxide

By Leave a Comment

The most abundant protein on the planet is an enzyme called ribulose-1,5-bisphosphate carboxylase/oxygenase, better known as RuBisCO.  Its critical role in photosynthesis makes life as we know it on earth possible.  What it does is convert carbon dioxide from the atmosphere into the organic matter contained in plants.

Getting plants to take up more carbon dioxide from the atmosphere is a key strategy for mitigating climate change.  Planting lots of trees is one way to do it.  Another is to get individual plants to capture more carbon dioxide.

Scientists at the University of Illinois have focused on getting plants to produce more RuBisCO which allows them to grow faster, consuming more carbon dioxide in the process.

Some plants are better than others at taking advantage of the earth’s rising carbon dioxide levels.  Among these are food crops like corn, sugarcane, and sorghum.  Such plants’ growth is not primarily limited by how much carbon dioxide is in the atmosphere but rather by how much RuBisCO is in their leaves.  The Illinois scientists tweaked genes in corn and sorghum to produce plants containing more RuBisCO.  Laboratory experiments on corn demonstrated faster corn growth.  Recent outdoor field experiments on sorghum demonstrated a 16% boost in its growth rate. 

Improving photosynthesis in this way is not only a potential strategy for increasing plants’ ability to combat climate change.  It is also a way to cope with the world’s increasing demand for food by producing crops that can grow larger and more quickly.

**********

Web Links

Scientists Engineer Crops to Consume More Carbon Dioxide

Photo, posted April 12, 2016, courtesy of K-State Research and Extension via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Capturing hot carbon dioxide

By Leave a Comment

Decarbonizing industries like steel and cement is a difficult challenge.  Both involve emitting large amounts of carbon dioxide both from burning fossil fuels and from intrinsic chemical reactions taking place.  A potential solution is to capture the carbon dioxide emissions and either use them or store them away.  But this sort of carbon capture is not easy and can be quite expensive.

The most common method for capturing carbon dioxide emissions from industrial plants uses chemicals called liquid amines which absorb the gas.  But the chemical reaction by which this occurs only works well at temperatures between 100 and 140 degrees Fahrenheit.  Cement manufacturing and steelmaking plants produce exhaust that exceeds 400 degrees and other industrial processes produce exhaust as hot as 930 degrees.

Costly infrastructure is necessary to cool down these exhaust streams so that amine-based carbon capture technology can work. 

Chemists at the University of California, Berkeley, have developed a porous material – a type of metal-organic framework – that can act like a sponge to capture CO2 at temperatures close to those of many industrial exhaust streams.  The molecular metal hydride structures have demonstrated rapid, reversible, high-capacity capture of carbon dioxide that can be accomplished at high temperatures.

Removing carbon dioxide from industrial and power plant emissions is a key strategy for reducing greenhouse gases that are warming the Earth and altering the global climate.  The captured CO2 can be used to produce value-added chemicals or can be stored underground or chemically-reacted into stable substances.

**********

Web Links

Breakthrough in capturing ‘hot’ CO2 from industrial exhaust

Photo, posted March 3, 2010, courtesy of Eli Duke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing emissions from cement

By Leave a Comment

Cement production accounts for about 7% of global carbon emissions.  It is one of the most difficult challenges for emissions reduction.  The emissions associated with producing cement come from both the energy used to provide heat for the process and from the chemical reactions that take place in the formation of cement.  Cement is an essential building block of society, and its use is not expected to decline over time.

A German company called Heidelberg Materials is embarking on an ambitious project to reduce carbon emissions from a cement plant in Norway.  They are building a facility to use absorbent chemicals to capture large quantities of carbon dioxide emitted through cement production.  More than half a ton of carbon dioxide arises from every ton of cement produced at the plant.

Once the carbon dioxide is captured it will be chilled to a liquid, loaded onto ships, and carried to a terminal farther up the Norwegian coast.  From there, it will be pumped into undersea rocks located 70 miles offshore and a mile and a half below the bottom of the North Sea.

With all of this complicated process going on, cement from the plant is likely to be quite expensive.  It might even be two or three times the price of ordinary cement.  Heidelberg Materials is counting on customers’ willingness to pay much more for cement that comes with green credentials. 

Can this be economically viable?  Heidelberg estimates that cement accounts for only about 2% of the cost of a large building project but as much as 50% of the emissions.  As a result, using carbon-free cement could be a relatively inexpensive way for builders to reduce emissions.

**********

Web Links

Cement Is a Big Polluter. A Plant in Norway Hopes to Clean It Up.

Photo, posted May 7, 2016, courtesy of Phillip Pessar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A giant solar plus storage facility

By Leave a Comment

One of the country’s largest co-located solar and battery energy storage projects is now fully operational.  The Gemini Solar+Storage project is located in Clark County, Nevada, about 30 minutes outside of Las Vegas.

The project’s 1.8 million solar panels can generate up to 690 megawatts of electricity, which is enough to supply about 10% of Nevada’s peak demand.  The facility is co-located with 380 megawatts of 4-hour battery storage, which is enough to supply Nevadans with 1,400 MWh of power after sundown.

The project makes use of a unique storage configuration that allows the storage system to be charged directly from the solar panels, resulting in increased efficiency and maximizing the capture and storage of solar energy.

The project has minimized the environmental impacts to the nearly 5,000-acre site.  Primergy, the project developer, took measures to leave vegetation in place, installed solar panels to follow the ground’s natural contours, and reduced the overall footprint by more than 20% through careful design.  The project created 1,300 union and prevailing wage jobs and contributed $483 million to Nevada’s economy.

Solar facilities are increasingly co-located with battery storage plants.  There is a huge project in Kern County California that includes 1.9 million solar panels capable of generating 875 megawatts of solar power and storing 3,287 megawatt-hours of energy.  The deserts of the southwest are prime locations for such facilities.

**********

Web Links

The house always wins: Massive Gemini solar + storage outside of Las Vegas reaches commercial operations

Photo courtesy of Quinbrook Infrastructure Partners.

Earth Wise is a production of WAMC Northeast Public Radio

The largest carbon removal plant

By Leave a Comment

Direct air capture (DAC) is process that removes carbon dioxide out of the air and stores it away where it can no longer trap heat in the atmosphere.  It is intended to be a way of getting rid of the greenhouse gases that have built up in the atmosphere.  In principle, it’s a great idea.  In practice, it is a huge challenge.

In 2017, a company called Climeworks became the first company to take carbon dioxide out of the air and sell it as a product for use in carbonated drinks and in greenhouses.  In 2021, the company opened a DAC plant called Orca in Iceland that captures CO2 and permanently stores it underground.  Clients like Microsoft pay Climeworks for doing this as a way of offsetting their own emissions.

Recently, Climeworks has started operating a new plant called Mammoth – also in Iceland – that will be able to capture about 10 times more carbon dioxide than Orca.  Iceland is a prime location for DAC technology because its abundant geothermal energy makes powering it cheap and environmentally friendly.

Mammoth, when fully operational, will remove about 36,000 tons of carbon dioxide a year, the largest DAC system in the world.  But there is a long, long way to go.  Microsoft alone emits nearly 13 million tons of carbon dioxide a year.

There are multiple DAC projects in development including several in the United States being funded by the Bipartisan Infrastructure Law.  The four DAC hubs being developed under the program are each supposed to have the capacity to capture at least a million metric tons of CO2 a year.

Whether DAC can make a real difference remains to be seen.

**********

Web Links

The world’s largest carbon removal plant is here, and bigger ones are on the way

Photo credit: Climeworks

Earth Wise is a production of WAMC Northeast Public Radio

Marine carbon dioxide removal

By Leave a Comment

About 30% of the carbon dioxide emitted by human activity is absorbed by the oceans.  As a result, they are getting warmer and more acidic, and the currents that help shape global weather are shifting.  To try to reduce global warming, people want to be able to store even more carbon dioxide in the oceans without the negative effects of doing so.

There are multiple efforts across the globe to achieve effective marine carbon dioxide removal.  Some are based on sinking carbon-rich materials to the bottom of the sea.  This is the marine equivalent of capturing CO2 from the air and storing it underground.  Other efforts involve increasing the alkalinity of the ocean, which increases its ability to chemically react with carbon dioxide as well as lowers its acidity, which is desirable in many ways.

Running Tide, a U.S.-based company, has been dumping thousands of tons of wood-industry waste 190 miles off the coast of Iceland.  The company has also been experimenting with dumping algae and kelp and sinking it deep below the ocean.  Such materials on land either get burned or decay, in both cases releasing CO2 into the atmosphere.  On the deep-sea bottom, the carbon is trapped.

Other efforts involve pumping seawater through electrodialysis filter systems to remove excess acidity or adding alkaline rocks to increase water alkalinity.

All of these efforts are a form of geoengineering, and like proposed ideas to cool the atmosphere, pose potential risks.  There is no silver bullet to solve the climate crisis.  It will take a combination of many solutions to address the issue of excess carbon dioxide in the atmosphere.  Marine carbon dioxide removal is one of the solutions that may play a role.

**********

Web Links

Scientists Are Trying to Coax the Ocean to Absorb More CO2

Photo, posted February 22, 2018, courtesy of Bobbie Halchishak/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Where not to plant trees

By Leave a Comment

Planting huge numbers of trees is often proposed as a way to reduce the severity of climate change.  Studies have looked at the potential for Earth‘s ecosystems to support large additional areas of forest and have found that it would be possible to have at least 25% more forested area than we do now.  This in turn could capture large amounts of carbon and substantially reduce the amount in the atmosphere.

A recent study by researchers at Clark University in Massachusetts and The Nature Conservancy mapped the climate impact of tree planting across the globe, identifying where it would be most and also least beneficial.  The study, published in Nature Communications, found that trees planted in arid, desert regions or in snowy places like the Arctic would, on balance, worsen warming rather than reduce it.

Trees take up carbon dioxide from the atmosphere, which helps to keep warming in check.  But trees with dark, green leaves also absorb heat from sunlight.   Snow and desert sand, on the other hand, are light-colored and reflect more sunlight back into space.  For this reason, trees planted in snowy areas or in the desert will absorb more sunlight than their surroundings.  This can negate the climate benefits of soaking up carbon dioxide.

Previous studies only looked at how much carbon dioxide would be removed by planting trees in order to determine how much warming would be prevented.  The new study finds that it matters where the trees are planted.

Fortunately, the new study also shows that tree planting projects that are currently underway or that are in the pipeline are largely concentrated in regions where they will indeed help slow global warming.

**********

Web Links

This Map Shows Where Planting Trees Would Make Climate Change Worse

Photo, posted April 5, 2022, courtesy of UC Davis Arboretum and Public Garden via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Moisture swing carbon capture

By Leave a Comment

As the world grapples with limiting the amount of carbon dioxide in the atmosphere, there is a growing need to capture the carbon dioxide that is emitted as well as preventing it from being emitted in the first place.  Carbon capture can be accomplished at the source of emissions (such as power plants) or it can be done by taking it out of the atmosphere.  The latter is called “direct air capture”.

It is not at all clear whether direct air capture can be accomplished on a scale that would really make a difference and at an acceptable cost either in dollars or energy expended.  But if it can be done that way, it would be a major tool in combatting climate change.

Direct air capture technology generally makes use of sorbent materials whose capacity to capture carbon dioxide and later release it is a function of temperature.  The process requires significant amounts of energy to release the carbon dioxide that has been captured. 

New research from Northwestern University makes use of the “moisture-swing” technique which uses materials whose ability to capture and release carbon dioxide depends on humidity rather than temperature.  While it takes some amount of energy to humidify the volume of air containing the sorbent material, it is very small compared to temperature-driven systems. 

There are many groups working with moisture-swing technology, but the Northwestern Group has identified a number of new sorbent materials with superior properties.

The fundamental questions of scalability and cost remain, but moisture-swing is a promising approach to direct air capture.  If carbon dioxide can be pulled out of the atmosphere in large volumes, it can be concentrated and stored or converted into useful products.

*********

Web Links

Pulling carbon dioxide right out of the air

Photo, posted May 15, 2020, courtesy of James Watt via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Planting Rocks To Capture Carbon | Earth Wise

By Leave a Comment

Getting humanity to stop dumping carbon dioxide into the atmosphere continues to be very challenging regardless of how increasingly apparent the need to do so becomes.  For this reason, climate change mitigation strategies increasingly include interventions in the form of removing carbon dioxide that is already there.  There are a variety of ways to draw carbon dioxide out of the atmosphere, but they face a host of technological, economic, and even environmental difficulties.

A new study at Yale University evaluated a type of climate intervention called enhanced rock weathering.  Rock weathering is a natural chemical process by which certain minerals absorb carbon dioxide over time.  Enhanced rock weathering is simply speeding up weathering such so it can have beneficial results soon enough to make a difference.

The study explored the potential of applying crushed basalt, which is a fast-weathering rock that forms when lava cools, to agricultural fields around the world.  Basically, the idea is for farmers to mix the crushed rocks into their fields. There is no real downside to doing this.  In fact, adding crushed basalt to fields rejuvenates depleted soils and helps counter ocean acidification.

The study simulated the results of enhanced rock weathering on 1,000 agricultural sites around the world.  Over a 75-year period, these sites would remove 64 billion tons of carbon dioxide from the atmosphere.  This is roughly the amount climate scientists believe is needed to take out of the atmosphere. 

Enhanced rock weathering has been used on a small scale on farms around the world.  Perhaps it is time to ramp up its use.

**********

Web Links

‘Planting’ rocks in farms, along with emissions reductions, could help meet key IPCC carbon removal goal

Photo, posted January 14, 2023, courtesy of Ron Reiring via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Storing Carbon Dioxide In The Ocean | Earth Wise

By 2 Comments

Reducing the amount of carbon dioxide entering the atmosphere means either shutting down emission sources (primarily curbing the use of fossil fuels) or capturing the CO2 as it is emitted.  Capturing carbon dioxide from smokestacks and other point sources with high concentrations is relatively efficient and can make economic sense.  Removing it from the air, which even at today’s dangerously high levels contains only 400 parts per million, is difficult and energy intensive.  And even when it is removed, it then must be stored somewhere.

Researchers at Lehigh University have developed a novel way to capture carbon dioxide from the air and store it in what is effectively the infinite sink of the ocean.  The approach uses an innovative copper-containing filter that essentially converts CO2 into sodium bicarbonate (better known as baking soda.)  The bicarbonate can be released harmlessly into the ocean.

This technique has produced a 300 percent increase in the amount of carbon dioxide captured compared with existing direct air capture methods.   It does not require any specific level of carbon dioxide to work.  The filter becomes saturated with the gas molecules as air is blown through it.  Once this occurs, seawater is passed through the filter and the CO2 is converted to dissolved bicarbonate.  Dumping it into the ocean has no adverse effect on the ocean.  It doesn’t change the salinity at all, and the stuff is slightly alkaline, which will help reduce ocean acidification.

Reusing the filter requires cleaning it with a sodium hydroxide solution, which can be created from seawater using electricity generated by waves, wind, or sun.

The filter, called DeCarbonHIX, is attracting interest from companies based in countries around the world.

**********

Web Links

Path to net-zero carbon capture and storage may lead to ocean

Photo, posted March 10, 2007, courtesy of Gail via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cheaper Carbon Capture | Earth Wise

By Leave a Comment

As the years roll by without sufficient progress in reducing carbon dioxide emissions, the need for technologies that can capture CO2 from its sources or remove it from the air becomes stronger and stronger.  People have developed various ways to capture carbon dioxide, but to date, they generally suffer from some combination of being too costly or not being able to scale up to the necessary magnitude.

Scientists at the Pacific Northwest National Laboratory in Richland, Washington recently announced the creation of a new system that they claim is the least costly to date that captures carbon dioxide and turns it into a widely-used chemical: methanol.

Technologies that simply capture carbon dioxide that then needs to be stored in some secure location are difficult to implement from a cost perspective.  The PNNL researchers believe that turning CO2 into methanol can provide the financial incentive for widespread implementation.   Methanol can be used as a fuel, a solvent, or an important ingredient in plastics, paint, construction materials, and car parts.

The system is designed to be installed in fossil fuel-fired power plants as well as cement and steel plants.  Using a capture solvent developed by PNNL, the system grabs carbon dioxide molecules before they are emitted and converts them into methanol. Creating methanol from CO2 is nothing new, but capturing the carbon dioxide and converting into methanol in one continuously flowing system is new.

More work is needed to optimize and scale the process and it may be several years before it is ready for commercial deployment.

**********

Web Links

Scientists Unveil Least Costly Carbon Capture System to Date

Photo, posted November 25, 2022, courtesy of Massachusetts Department of Environmental Conservation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon Capture In Wyoming | Earth Wise

By Leave a Comment

Wyoming produces about 40% of our country’s coal and many towns in the state were built because of and make their living from it.  With coal’s plummeting share in the nation’s electricity, there is a great deal of anxiety among residents of those towns.

As carbon dioxide levels in the atmosphere continue to climb, there is a growing sense that cutting emissions will not happen quickly enough and it will be necessary to pull the greenhouse gas out of the atmosphere.  The current long-term government climate strategy assumes that carbon removal will account for 6 to 8 percent of the nation’s greenhouse gas reductions by 2050.

The Inflation Reduction Act passed in August provides $3.5 billion to help build “direct air capture hubs” around the country, with an emphasis on fossil fuel-dependent communities such as many in Wyoming. 

The town of Rock Springs, Wyoming is home to the Jim Bridger Coal Plant. A company called CarbonCapture, Inc., is launching Project Bison, which will build a direct air capture facility outside of town that is set to begin operations next year.  It will initially capture 10,000 metric tons of CO2 per year but plans to expand that to 5 million tons a year by 2030. 

That would be far more than any current carbon capture plant can do. The largest plant in the world, located in Iceland, pulls in only about 4,000 metric tons a year.

There are many problems associated with carbon capture.  It uses up very large amounts of energy, possibly presents environmental problems, and is very expensive.  In short, the technology has a long way to go before becoming viable.  However, this may ultimately be another example where necessity is the mother of invention.

**********

Web Links

Carbon Removal Is Coming to Fossil Fuel Country. Can It Bring Jobs and Climate Action?

Photo, posted July 22, 2012, courtesy of Max Phillips via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon Capture Booming | Earth Wise

By Leave a Comment

For the world to reach a state of net-zero emissions, it is going to require more than the ongoing transition to renewable energy sources.  There will also need to be efforts to capture the emissions from sources that can’t easily eliminate their pollution.  These include steel mills, cement plants, and other industrial sites.  At least for the foreseeable future,  a number of essential industries have no other viable path to deep decarbonization, and carbon capture and storage projects are the only promising strategy on hand.

Companies use CCS to filter emissions from fossil fuel power plants and industrial facilities and then bury the captured carbon underground, often in deep caverns.

Over the past 12 months, the pipeline for carbon capture and storage projects has grown by 44%.  This year, firms have announced 61 new CCS projects, bringing the total number of commercial projects in the global pipeline to 196, which includes about 30 that are already in operation.  Another 11 are under construction, and 153 are in development.

When all of these projects are completed, they will have the capacity to capture a total of about 270 million tons of carbon dioxide per year.  Estimates are that there need to be 1,400 million tons locked away each year to reach zero-emissions.  So, the existing project pipeline constitutes about 20% of what is ultimately needed.

The recently passed Inflation Reduction Act boosts tax incentives for carbon capture.  Analysts believe this could multiply U.S. deployment of the technology more than 10-fold.  Globally, it is expected that CCS will continue its rapid growth as countries ramp up investments in the technology.

**********

Web Links

Carbon Capture Projects See Meteoric Growth in 2022

Photo, posted August 22, 2022, courtesy of Nenad Stojkovic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Cheap Material For Carbon Capture | Earth Wise

By Leave a Comment

The recently passed Inflation Reduction Act includes significant support for carbon capture technologies. Eliminating fossil fuel burning is essential for halting climate change, but in the interim, methods for capturing emissions of carbon dioxide and either storing it or turning it into usable products are increasingly necessary.

There are a variety of techniques being developed for carbon capture but at this point, none of them are commercially viable.  The best technique in use today involves piping flue gases through chemicals called liquid amines, which bind CO2.  The process requires large amounts of energy to release the bound carbon dioxide so it can be concentrated and stored.  As a result, it is complicated and expensive.

Researchers at UC Berkeley, Stanford, and Texas A&M University have developed a carbon capture method using melamine, which is an inexpensive polymer used to make Formica, as well as low-cost dinnerware, industrial coatings, and other plastics.  Porous melamine itself adsorbs CO2 to a limited extent.  But the researchers discovered that adsorption could be much improved by adding the chemical DETA (diethylenetriamine) to bind the CO2.  In addition, adding cyanuric acid increased the melamine pore size and radically improved CO2 capture efficiency even more.

The result is a material that is more efficient even than exotic carbon capture materials like metalorganic frameworks and is much cheaper and easier to make. The researchers aim to design equipment that can used in industrial facilities, attached to buildings and other structures, or even to the tailpipes of gas-powered vehicles.

**********

Web Links

A simple, cheap material for carbon capture, perhaps from tailpipes

Photo, posted June 10, 2006, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mangrove Forests And Climate Change | Earth Wise

By Leave a Comment

Mangrove forests play a vital role in the health of our planet.  These coastal forests are the second most carbon rich ecosystems in the world.  A patch of mangrove forest the size of a soccer field can store more than 1,000 tons of carbon. It does this by capturing carbon from the air and storing it in leaves, branches, trunks, and roots.

Mangrove forests only grow at tropical and subtropical latitudes near the equator because they cannot withstand freezing temperatures.  These forests can be recognized by their dense tangle of prop roots that make the trees look like they are standing on stilts above the water.  These roots allow the trees to handle the daily rise and fall of tides.  Most mangroves get flooded at least twice a day.  The roots also slow the movement of tidal waters, which allows sediments to settle out of the water and build up on the muddy bottom.  Mangrove forests stabilize coastlines, reducing erosion from storms, currents, waves, and tides.

A new study by the University of Portsmouth in the UK looked at the effects of climate change on how carbon is stored in mangrove forests.  In mangrove ecosystems, a variety of organisms break down fallen wood.  These include fungi, beetle larvae, and termites.  Closer to the ocean, clams known as shipworms degrade organic material.

Climate change is disrupting these processes in at least two ways.  Rising sea levels are changing the way sediments build up and increased ocean acidity is dissolving the shells of marine organisms like shipworms.

Mangrove forests are crucial to mitigating climate change, and changes to the functioning of the carbon cycle of those ecosystems are a threat to their ability to perform that function.

**********

Web Links

Study Reveals How Climate Change Can Significantly Impact Carbon-Rich Ecosystem

Photo, posted March 24, 2014, courtesy of Daniel Hartwig via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Assessing Human-Caused Wildlife Mortality | Earth Wise

By Leave a Comment

Bycatch is the fishing industry term used to describe the deaths of non-target fish and ocean wildlife during the fishing process.  Some bycatch species are thrown away because regulations prohibit them from being kept.  Others are thrown out because they won’t fetch high enough prices.  According to some estimates, global bycatch amounts to about 10% of the world’s total catch. 

Approximately half of global bycatch is a result of trawling.  Trawling is a method of commercial fishing that involves pulling or dragging a fishing net – called a trawl – through the water or across the seabed in hopes of catching fish.  Commercial fishing companies favor towing trawl nets because large quantities of fish can be caught.  But the method is destructive to the seafloor and leads to the indiscriminate catch of all sorts of species, including whales, dolphins, porpoises, sharks, seals, rays, turtles, and seabirds. 

Researchers have developed a new method to assess the sustainable levels of human-caused wildlife mortality.  When this method is applied to a trawl fishery in Australia, it shows that the dolphin capture is not sustainable.  The study, led by scientists at the University of Bristol in the U.K. and United Arab Emirates University, modeled different levels of dolphin capture, including those reported in logbooks and those reported by independent observers.  According to the findings, which were recently published in the journal Conservation Biology, even the lowest recorded dolphin capture rates are not sustainable. 

The new approach is extremely adept at assessing human-caused mortality to wildlife, and can be applied to fisheries bycatch, hunting, lethal control measures, or even wind turbine collisions.

**********

Web Links

Wasted Catch

Dolphin bycatch from fishing practices unsustainable, study finds

Photo, posted May 18, 2011, courtesy of Pete Markham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Capturing Carbon Dioxide With Plastic | Earth Wise

By 2 Comments

The world is awash in both waste plastic and in carbon dioxide emissions.   Researchers at Rice University have discovered a chemical technique for making waste plastic into an effective carbon dioxide absorbent for industry.

Chemists at Rice reported in the journal ACS Nano that heating plastic waste in the presence of potassium acetate produces particles with nanometer-scale pores that trap carbon dioxide molecules.   According to the researchers, these particles could be used to remove CO2 from the flue gas streams of power plants.

Significant sources of CO2 emissions like power plant exhaust stacks could be fitted with this waste-plastic-derived material to absorb large amounts of carbon dioxide that would otherwise enter the atmosphere. 

The Rice University process is an enhancement to the current process of pyrolyzing waste plastic – that is, breaking it down in the presence of heat.  By pyrolyzing plastic in the presence of potassium acetate, porous particles are formed that can hold up to 18% of their own weight in carbon dioxide.

According to the researchers, the cost of capturing carbon from a power plant would be $21 a ton, which is far less expensive than existing energy-intensive processes used to pull carbon dioxide from natural gas feeds.

The sorbent material can be reused.  Heating it to about 167 degrees Fahrenheit releases trapped carbon dioxide from the pores and regenerates about 90% of the material’s binding sites.

The Rice process may represent a much better way to capture carbon dioxide from power plant exhaust stacks.  It could be a way to make use of one environmental problem – waste plastic – to deal with another one.

**********

Web Links

Treated plastic waste good at grabbing carbon dioxide

Photo, posted April 19, 2021, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Pollution Into Cash | Earth Wise     

By Leave a Comment

Power plants and other industrial facilities are a major source of carbon emissions.  There are a variety of techniques under development to prevent those emissions by capturing them rather than releasing them into the atmosphere.  All of them add costs to the functioning of the facility.  A good way to offset those costs is to convert the emissions into useful products, ideally making it profitable to capture emissions.

Engineers at the University of Cincinnati have developed an electrochemical system that converts carbon dioxide into ethylene, which is a chemical used in a wide range of manufacturing.  Ethylene has sometimes been called “the world’s most important chemical”.  It is used in many kinds of plastics, textiles, and the rubber found in tires and insulation. It is also used in heavy industry such as steel and cement plants as well as in the oil and gas industry.

The Cincinnati process is a two-stage cascade reaction that converts carbon dioxide to carbon monoxide and then into ethylene.  It is based on the underlying principle of the plug-flow reactor that is used for variety of production applications.  The study, published in the journal Nature Catalysis, demonstrates that the process has high ethylene selectivity – meaning that it effectively isolates the desired compound – as well as high productivity – meaning that it makes a lot of it.  The system will take more time to become truly economical, but the researchers are continuing to make progress on that front with improved catalysts.

The researchers believe that this technique can reduce carbon emissions and make a profit doing it.  Power plants and other facilities emit a lot of carbon dioxide.  With this process, it may be possible to capture it and produce a valuable chemical.

**********

Web Links

Conversion process turns pollution into cash

Photo, posted February 27, 2018, courtesy of Cyprien Hauser 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...)