Engineers created a new device to remove carbon dioxide from the air, which could be a new and significant way to fight against climate change. The new system can work on the gas at virtually any concentration level, even down to the roughly 400 parts per million currently found in the atmosphere.
Let’s understand the cycle of carbon dioxide
Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms.
Atmosphere carbon dioxide derives from multiple natural; volcanic outgassing, the combustion of organic matter, and the respiration processes of living aerobic organism.
The man-made the source of carbon dioxide come mainly from the burning of various fossil fuels for power generation and transport use.
It is also produced by various microorganisms from fermentation and cellular respiration. Plants convert carbon dioxide to oxygen during a process called photosynthesis, using both the carbon and the oxygen to construct carbohydrates.
In addition, plants also release oxygen to the atmosphere, which is subsequently used for respiration by heterotrophic organisms, forming a cycle.
It is often referred to by its formula CO2.
CO2 is present in the Earth’s atmosphere at a very high concentration and acts as a greenhouse gas. it's solid-state, it is called dry ice and it is a major component of the carbon cycle.
How harmful it is for Earth’s atmosphere?
Scientists say increased carbon dioxide in Earth’s atmosphere is causing global temperature to warm – sea-level rise – and storms, droughts, floods, and fires to become more severe.
This atmospheric layer prevents the earth from cooling at night. One result is a warming of ocean waters. Oceans absorb carbon dioxide from the atmosphere.
However, higher water temperatures compromise the oceans’ ability to absorb carbon diode. Over time, the effects of carbon dioxide are compounded.
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According to the National Oceanic Atmospheric Administration (NOAA). Another environmental effect of carbon dioxide on air pollution is climate change. The earth’s surface temperature has raised over the last 100 years.
Scientists believe carbon dioxide pollution is the primary culprit. The effect is highly complex. Evidence shows, however, that ocean water levels have increased, resulting in a loss of shoreline and coastal wetlands.
Carbon dioxide is a contributor to the environmental effect known as acid rain.
Emission released from fossil fuel-burning energy plants combines with moisture in the air. The result is precipitation with acid content. Documented evidence shows the physical damage to trees and other plant life.
Water and soil pollution occurs from the acidic precipitation. A complicating factor is the mobility of emissions. The effects of carbon dioxide can be seen and felt far from their sources, making their impacts on air pollution more serious.
Impact on human health
Carbon dioxide emission impact human health by displacing oxygen in the atmosphere, breathing becomes more difficult as carbon dioxide levels rise.
In closed areas, high levels of carbon dioxide can lead to health complaints such as headaches. Carbon dioxide levels may indicate high levels of the other harmful air pollutants such as volatile organic compounds that contribute to indoor air pollution.
How this new technique would help to wipe out carbon dioxide?
According to the researchers, most methods of removing carbon dioxide from a stream of gas require higher concentrations, such as those found in the flue emissions from fossil fuel-based power plants.
A few variations have been developed that can work with the low concentrations found in air, nut the new method is significantly less energy-intensive and expensive.
The device is essentially a large, specialized battery that absorbs carbon dioxide from the air (or another gas stream) passing over its electrodes as it is being charged up, and then released the has as it is being discharged.
In operation, the device would simply alternate between-charging and discharging, with fresh air or feed gas being blown through the system during the charging cycle, and then the pure, concentrated carbon dioxide being blown out during the discharging.
As the battery charges, an electrochemical reaction takes place at the surface of each of a stack of electrodes. These are coated with a compound called polyanthaquinone, which is composited with carbon nanotubes.
The electrodes have a natural affinity for carbon dioxide and readily react with its molecules in the airstream or feed gas, even when it is presented at very low concentrations.
The reverse reaction takes place when the battery discharged during which the device can provide part of the power needed for the whole system – and in the process ejects a stream of pure carbon dioxide.
The whole system operated at room temperature and normal air pressure.
Advantage of this amazing technology
The greatest advantage of this technology over most other carbon capture or carbon-absorbing technologies is the binary in nature of the adsorbent’s affinity to carbon dioxide.
In other words, the electrode material, but its nature, “has either a high affinity or an affinity whatsoever,” depending on the battery’s state of charging or discharging.
Other reactions used for carbon capture require intermediate chemical processing steps or the input of significant energy such as heat, or pressure differences.
"This binary affinity allows capture of carbon dioxide from any concentration, including 400 parts per million, and allows its release into any carrier stream, including 100 percent CO2,” as any gas flows through the stack of these flat electrochemical cells, during the release step the captured carbon dioxide will be carried along with it.
For example, if the desired end-product is pure carbon dioxide to be used in the carbonation of beverages, then a stream of the pure gas can be blown through the plates. The captured gas is then released from the plates and joins the stream.
For example, if the desired end-product is pure carbon dioxide to be used in the carbonation of beverages, then a stream of the pure gas can be blown through the plates. The captured gas is then released from the plates and joins the stream.
In some soft-drink bottling plants, fossil fuel is burned to generate the carbon dioxide needed to give the drinks their fizz. Similarly, some farmers burn natural gas to produce carbon dioxide to feed their plants in greenhouses.
The new system could eliminate the need for fossil fuels in these applications, and in the process actually, be taking the greenhouse gas right out of the air.
Alternatively, the pure carbon dioxide stream could be compressed and injected underground for long-term disposal, or even made into fuel through a series of chemical and electrochemical processes.
The process this system uses for capturing and releasing carbon dioxide "is revolutionary". "All of this is at ambient conditions -- there's no need for thermal, pressure, or chemical input. It's just these very thin sheets, with both surfaces active, that can be stacked in a box and connected to a source of electricity."The new system could eliminate the need for fossil fuels in these applications, and in the process actually, be taking the greenhouse gas right out of the air.
Alternatively, the pure carbon dioxide stream could be compressed and injected underground for long-term disposal, or even made into fuel through a series of chemical and electrochemical processes.
How much carbon can be captured from the technology?
Compared to other existing carbon capture technologies, this system is quite energy-efficient, using about one gigajoule of energy per ton of carbon dioxide captured, consistently. Other existing methods have energy consumption which varies between 1 to 10 gigajoules per ton, depending on the inlet carbon dioxide concentration.
Source
The researchers have set up a company called Verdox to commercialize the process, and hope to develop a pilot-scale plant within the next few years.
The technique, based on passing air through a stack of charged electrochemical plates, is described in a new paper in the journal Energy and Environmental Science, by MIT postdoc Sahag Voskian, who developed the work during his PhD, and T. Alan Hatton, the Ralph Landau Professor of Chemical Engineering.
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