Why can't we just recycle polluted air?

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In summary, the conversation discusses the idea of using filters to separate harmful gases from the air, specifically carbon dioxide, as a solution to pollution caused by burning trash. However, it is mentioned that this process is energy-intensive and there is no place to store the separated gases. Instead, the conversation suggests using carbon capture programs, such as algae systems, to remove CO2 from the air and potentially use it as a feedstock. Additionally, reforestation is mentioned as a possible solution. The conversation also acknowledges the challenges of finding a practical and economical way to manage CO2 emissions.
  • #1
ayami123
just a question,

I mean, burning trash causes polluted air.
then
why can't we just filter the polluted air, separating the oxygen and other harmful gas and release only oxygen in the air?

thus solving trash and polluted air at the same time.
 
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  • #2
It's difficult/energy intensive and we don't have a place to put the harmful gasses. The atmosphere is big!

Also, these days the "harmful gas" is mainly carbon dioxide. Anti-pollution regulations have mostly curtailed the emissions of other harmful gases.
 
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  • #3
russ_watters said:
It's difficult/energy intensive and we don't have a place to put the harmful gasses. The atmosphere is big!

Also, these days the "harmful gas" is mainly carbon dioxide. Anti-pollution regulations have mostly curtailed the emissions of other harmful gases.
no, I mean, gas is basically a combination of chemical formulas right,

and just like carbon is CO2
why not just split the C and O2
thus will be able to give the air the O2 it needs,
while the C will be used as well carbon metal ?
 
  • #4
ayami123 said:
no, I mean, gas is basically a combination of chemical formulas right,

and just like carbon is CO2
why not just split the C and O2
thus will be able to give the air the O2 it needs,
while the C will be used as well carbon metal ?
It takes exactly the same amount of energy to split CO2 as you got from making it. You're talking about burning and then unburning it.
 
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  • #5
russ_watters said:
It takes exactly the same amount of energy to split CO2 as you got from making it. You're talking about burning and then unburning it.
oh, I mean what's the purpose of the filters then ?
don't the filters also kind of block the carbon in the CO2 ?

I have seen some Factories like have some sort of filters in their chimney.
 
  • #6
ayami123 said:
oh, I mean what's the purpose of the filters then ?
don't the filters also kind of block the carbon in the CO2 ?

I have seen some Factories like have some sort of filters in their chimney.
Filters can block particulate pollution like soot, but can't filter gases. But these days there isn't much soot - that's caused by incomplete burning.
 
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  • #7
so the challenge today is to,
somehow be able to burn and unburn a gas.

I mean I hear the news complaining about carbon emission.
I kind of think that separating C from CO2 is easy,

didn't know the current technology for that is requires a lot of energy.
 
  • #8
ayami123 said:
so the challenge today is to,
somehow be able to burn and unburn a gas.

I mean I hear the news complaining about carbon emission.
I kind of think that separating C from CO2 is easy,

didn't know the current technology for that is requires a lot of energy.
It's not a technology issue, it is a chemistry/conservation of energy issue. Running a reaction forwards and backwards creates/requires the same amount of energy. It has to - it's the same reaction.
 
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  • #9
ayami123 said:
oh, I mean what's the purpose of the filters then ?
don't the filters also kind of block the carbon in the CO2 ?

I have seen some Factories like have some sort of filters in their chimney.
Filters typical trap 'particulate' matter, which can be a combination of ash, or unburned metal oxides leftover from coal or oil, and carbonaceous products. Gases would pass through the filter.

ayami123 said:
so the challenge today is to,
somehow be able to burn and unburn a gas.

I mean I hear the news complaining about carbon emission.
I kind of think that separating C from CO2 is easy,

didn't know the current technology for that is requires a lot of energy.
There are various so-called 'carbon capture' programs in which CO2 is captured at the source, i.e., at the exit of the combustion system. For example,

https://energyfactor.exxonmobil.com/reducing-emissions/carbon-capture-and-storage/
https://www.battelle.org/government...esource-management/carbon-management-services

https://en.wikipedia.org/wiki/Carbon_capture_and_storage

In the air, CO2 is about 400 to 500 ppm, and it takes energy to compress the air and separate into constituent gases. Then what does one do with the CO2? Or rather, to what process can it be used as a feedstock? Fischer-Tropsch synthesis is one possibility, but it would be more economical to capture CO2 at the source.

Algal systems are a possibility as are reforestation, or use of forests, both inland and coastal.

https://en.wikipedia.org/wiki/Biosequestration

https://qz.com/1718988/algae-might-be-a-secret-weapon-to-combatting-climate-change/
https://www.frontiersin.org/articles/10.3389/fmars.2019.00029/full

https://www.energy.gov/fe/articles/...ects-develop-algae-based-technologies-capture

Integrating Algae with Bioenergy Carbon Capture and Storage (ABECCS) Increases Sustainability
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017EF000704
 
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  • #10
Astronuc said:
Filters typical trap 'particulate' matter, which can be a combination of ash, or unburned metal oxides leftover from coal or oil, and carbonaceous products. Gases would pass through the filter.There are various so-called 'carbon capture' programs in which CO2 is captured at the source, i.e., at the exit of the combustion system. For example,

https://energyfactor.exxonmobil.com/reducing-emissions/carbon-capture-and-storage/
https://www.battelle.org/government...esource-management/carbon-management-services

https://en.wikipedia.org/wiki/Carbon_capture_and_storage

In the air, CO2 is about 400 to 500 ppm, and it takes energy to compress the air and separate into constituent gases. Then what does one do with the CO2? Or rather, to what process can it be used as a feedstock? Fischer-Tropsch synthesis is one possibility, but it would be more economical to capture CO2 at the source.

Algal systems are a possibility as are reforestation, or use of forests, both inland and coastal.

https://en.wikipedia.org/wiki/Biosequestration

https://qz.com/1718988/algae-might-be-a-secret-weapon-to-combatting-climate-change/
https://www.frontiersin.org/articles/10.3389/fmars.2019.00029/full

https://www.energy.gov/fe/articles/...ects-develop-algae-based-technologies-capture

Integrating Algae with Bioenergy Carbon Capture and Storage (ABECCS) Increases Sustainability
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017EF000704
it's sad that the only way to actually manage CO2 is to capture it and put it underground.

I though we could use the carbon element in the air as carbon resource =_=

wish there is a way to just split the chemical compound so we can just reuse the elements.

oh well, it's just a fantasy then.so the real options are Economical or Geological factors.

reduce the Factories - highly unlikely as this might affect the economic output of the country.
reduce the Use of Fossil Fuels or Coal = Highly Unlikely as the world need more Energy as I can understand right now ?

add more forest - semi probable?
or just have algae farms ?
 
  • #11
ayami123 said:
or just have algae farms ?
Is there an "e-e-c-h-c-o-h-o" in here?
 
  • #12
Yes, unburning fuel is roundabout vs reducing/stopping burning fuel. It's a lot easier to stop burning fuel than it is to burn it then unburn it.
ayami123 said:
reduce the Factories - highly unlikely as this might affect the economic output of the country.
reduce the Use of Fossil Fuels or Coal = Highly Unlikely as the world need more Energy as I can understand right now ?
It wouldn't be difficult to reduce the fossil fuel usage for electricity to near zero in a couple of decades if we wanted to do it. But unfortunately there is more political capital in saying we want to do it than in actually doing it, so we won't.
add more forest - semi probable?
Yes that would be good but unfortunately it is currently accepted (again as a political choice) that burning down forests is "carbon neutral" so we're going in the wrong direction with that.
 
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  • #13
ayami123 said:
it's sad that the only way to actually manage CO2 is to capture it and put it underground.

I though we could use the carbon element in the air as carbon resource =_=

wish there is a way to just split the chemical compound so we can just reuse the elements.

oh well, it's just a fantasy then.so the real options are Economical or Geological factors.

reduce the Factories - highly unlikely as this might affect the economic output of the country.
reduce the Use of Fossil Fuels or Coal = Highly Unlikely as the world need more Energy as I can understand right now ?

add more forest - semi probable?
or just have algae farms ?
Well, to add to what Astronuc said, there are some potentials in CO2 dissociation through solar energy. In my field (Photochemistry and Coordination Chemistry), this seems to be one of the bigger projects out there.
However, I have yet to see a scalable report; it can sound good at laboratory levels but it gets impractical at industrial level. For example, to bring it to an industrial level, it usually require a synthetic method that is usually quite different from laboratory level synthesis. Whether that method is available or not depends on what exactly is going to be synthesized, but a tremendous chemical engineering would be required. Not to mention that we are also neglecting the energy and resource costs in producing the compounds.
 
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  • #14
I think any carbon capture is actually immensely impractical, due to the enormous scale we would need to achieve in order to adequately deal with the problem. It would need to exceed the current size of the oil industry, in just a decade or two.
 
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  • #15
HAYAO said:
Well, to add to what Astronuc said, there are some potentials in CO2 dissociation through solar energy. In my field (Photochemistry and Coordination Chemistry), this seems to be one of the bigger projects out there.
However, I have yet to see a scalable report; it can sound good at laboratory levels but it gets impractical at industrial level. For example, to bring it to an industrial level, it usually require a synthetic method that is usually quite different from laboratory level synthesis. Whether that method is available or not depends on what exactly is going to be synthesized, but a tremendous chemical engineering would be required. Not to mention that we are also neglecting the energy and resource costs in producing the compounds.

green slime said:
I think any carbon capture is actually immensely impractical, due to the enormous scale we would need to achieve in order to adequately deal with the problem. It would need to exceed the current size of the oil industry, in just a decade or two.
I kind of saw this in the youtube,
I thought, only I came to think of this method haha,
There are other companies doing it already hehe.

But from the looks of it,
Looks like it's quite expensive.

Reference article: From BBC
 
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  • #16
russ_watters said:
Yes, unburning fuel is roundabout vs reducing/stopping burning fuel. It's a lot easier to stop burning fuel than it is to burn it then unburn it.

It wouldn't be difficult to reduce the fossil fuel usage for electricity to near zero in a couple of decades if we wanted to do it. But unfortunately there is more political capital in saying we want to do it than in actually doing it, so we won't.

Yes that would be good but unfortunately it is currently accepted (again as a political choice) that burning down forests is "carbon neutral" so we're going in the wrong direction with that.
You probably, and most people do not, is that N.American earthworms, or at least quite a lot of them, are an invasive species bought in with the European settlers..

The last ice age pushed the native ones south and they are slowly creeping northwards, but the ones actually further north are the invasive species type.
( and most people would say that they are great for gardening )

But undergrowth is affected, and a consequence is less carbon capture for the forest.
Rather than being a carbon sink, the Boreal forests of Canada do become a carbon source as the earthworms move in.
https://laidbackgardener.blog/2021/01/04/earthworms-are-bad-news-for-north-american-forests/

Tree planting, as you say, is slightly political.
 
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  • #17
Circling back to the original post idea of burning trash
ayami123 said:
thus solving trash and polluted air at the same time
The company I work for sold a few "trash-burners" back in the late 1980s to generate electricity using municipal trash as fuel. This seemed a good idea, as many cities suffer with ever-growing landfills. I don't know if any of these power plants are still operating. Combustion generates CO2, so maybe these units have been retired.

I had a friend who worked at one of the trash burners, and he related the biggest problem operationally was the fuel stream. Municipal trash is not uniform like nat gas or coal; the trash stream is not all combustible and contains all kinds of unexpected items. The conveyor system that brings the trash to the burner was frequently jammed by stuff like grocery carts, shutting down the unit until the system could be un-jammed. Hard to believe that people toss grocery carts into dumpsters, but my friend said it happened all the time.
 
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  • #18
ayami123 said:
burning trash causes polluted air.
then
why can't we just filter the polluted air
Kind of that what happens. But 'polluted air' is a bit broad term, and can mean very different things depending on the context. Since you brought up burning trash, the release of CO2 and H2O is acceptable, and the focus is on everything else. Trash can contain a very wide variety of materials, so you have to filter against NOx, complex organic materials: even volatile metals and Sulfur.
They are removed by scrubbing. (Source is random google find, but I've found it acceptable starting point for further digging.)

Removing the CO2 is a different topic, as the turns of the topic already proved it.
 

1. Why can't we just recycle polluted air?

The process of recycling polluted air is not as simple as recycling other materials such as plastics or paper. The air is a complex mixture of gases, pollutants, and other particles that cannot be easily separated and recycled. Additionally, some pollutants cannot be removed from the air through recycling methods.

2. Can't we just use air filters to clean the polluted air?

Air filters can help to reduce the amount of pollutants in the air, but they are not a long-term solution for recycling polluted air. Filters can only capture certain types of pollutants and they need to be replaced regularly, which can be costly and time-consuming. Plus, they do not address the root cause of the pollution.

3. Is there a technology that can recycle polluted air?

There are various technologies being developed to address air pollution, such as air purifiers and scrubbers. However, these technologies are not yet advanced enough to fully recycle polluted air. They can help to reduce pollution levels, but they are not able to completely remove all pollutants from the air.

4. Why can't we just plant more trees to recycle polluted air?

Trees are known for their ability to absorb carbon dioxide and produce oxygen, but they are not a solution for recycling polluted air. Trees cannot remove all types of pollutants from the air and they require a significant amount of time and space to have a noticeable impact on air quality. Additionally, planting more trees does not address the sources of pollution.

5. If we can't recycle polluted air, what can we do to improve air quality?

While we may not be able to recycle polluted air, there are several steps we can take to improve air quality. These include reducing our use of fossil fuels, using alternative modes of transportation, and supporting policies and regulations that aim to reduce pollution. It is also important to educate ourselves and others about the sources and impacts of air pollution and make small changes in our daily habits to reduce our own contributions to air pollution.

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