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limewater filter

 I don't remember the chemistry exactly, but...
 
(+1, -1) 		  [vote for,
against]

make it so that exhaust has to bubble up through a tube filled with limewater (aqueous calcium hydroxide).valves and pumps will prevent the water from filling the car. this way, carbon dioxide will be changed into calcium carbonate, which is chalk, i think. anyway, another valve could add really concentrated limewater paste as needed, and at the end of the day it gets scooped out and put in a bucket. The sidewalk chalk companys could offer a rate per pound if you bring it in, like a bottle depot. the point is, less co2 pollution=good.
—schematics, Jul 09 2004

Not original http://www.freerepu...s/news/664001/posts
[Madai, Oct 04 2004, last modified Oct 21 2004]

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       just out of curiousity, in England, is there such thing as pounds per pound? because that would be kinda funny. or have pounds been replaced by euros?
—schematics, Jul 09 2004
   

       Pounds Sterling have not been replaced by euros, and pounds avoirdupois have not been replaced by kilograms.
—angel, Jul 09 2004
   

       angel remember it would be an offence to sell anything by the pound, would be £ per kilo rather than £ per lb.
—engineer1, Jul 09 2004
   

       //it would be an offence to sell anything by the pound//
Actually, it's not, despite the fact that people have been prosecuted for it. The regulations that prohibit sales in Imperial measures are, themselves, illegal, but it's a complex and emotive issue, and this is not the place for it.
—angel, Jul 09 2004
   

       the aqueous calcium hydroxide reacts with the co2 and makes a precipitate that I can't remember. chemists, a little help here? I know I've done the experiment where you blow through a straw and the bubbles make white stuff form in the water because of the co2 in your breath. also, even tthough kilos are the standard unit of mass measurement in Canada, sometimes places sell stuff by the pound. Don't know why, though.
—schematics, Jul 09 2004
   

       calcium carbonate?
—po, Jul 09 2004
   

       without really checking, I believe calcium hydroxide [Ca(OH)2] and CO2 react to make water and calcium carbonate [CaCO3] which is chalk or limestone   

       ah, [po] beat me to it...
—luecke, Jul 09 2004
   

       perfect. I'm gonna edit that in. Thanks.
—schematics, Jul 09 2004
   

       So I'm not sure of the accuracy of this statement, but I found on the web that the average car (lets not even talk about SUV's) produces 5 tons of CO2 in a year... (whips out calculator)... so that means you would have to supply roughly 45 pounds of calcium hydroxide and remove 60 pounds of chalk PER DAY if you were to remove all of the CO2. Ouch. I suppose it wouldn't be 100% efficient anyways, but it looks like this might cause some problems.
—luecke, Jul 09 2004
   

       that's a lot of carbon, but I think that because of the bubbles, it wouldn't produce quite that much. If it does, good for the environment. maybe it could be put into cement blocks and stuff, or used as some otheer building material. gyprock or drywall, maybe.
—schematics, Jul 09 2004
   

       the chemical formula used by photosynthesis combines CO2 and H2O to make sugar which would be nice if we could do it!
—po, Jul 09 2004
   

       at normal air temperature the reaction works just fine, and if it's a cold day, it's probably close enough to the heat of the car. and exhaust is plenty warm anyway.
—schematics, Jul 09 2004
   

       good question, and for the answer we say.. Look! a distraction!   

       I really don't know I wonder where high school teachers get it.
—schematics, Jul 09 2004
   

       [schematics] - I think [Tabs] is implying that it will have to be produced, and that the process to make it will require energy. So where do you get that energy from? Probably from a process that creates CO2 as a by-product, which kinda negates the whole point of what you are doing...
—luecke, Jul 09 2004
   

       [schematics] and [Tabs] have a good point. Worse, there is more. Producing lime is a VERY energy intensive process. In fact, it is one of the most energy intensive industrial products on the planet.   

       Even worse: Greenhouse gases are released not only by the fuel used to produce it, but additional greenhouse gases are released from the raw material - limestone! CaCO3.   

       Even if renewable energy is used to produce the lime, there is a net increase in greenhouse gas emissions, so this would actually result in MORE CO2 being released into the atmosphere.   

       Lime is, however, used to remove sulfur dioxide from flue gases in coal fired power plants. If it were practical to use it for CO2 removal they would do that also, but it isn't. At best, it could be used to capture CO2 and to transport it to a facility where the carbonate is turned back into lime and the CO2 injected underground, or combined with silicate rocks, etc.   

       It would work, but it has a fatal flaw, you still need to sequester the gaseous CO2 produced during lime production somewhere, and that is not easy.
—anticyclone, Nov 07 2004
   

       [anticyclone]just use more calcium hydroxide....
—Cubical_View, Nov 08 2004
   
      
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