A way to make water potable using carbon dioxide • Hacker News Board

Re: A way to make water potable using carbon dioxide

#11

Post by ams6110 » Sun, May 21, 2017, 7:26 PM UTC

haneefmubarak wrote: post #6

> he imagines [the necessary CO2] would come from power stations and other industrial processes, such as cement-making, that produce the gas in large quantities as exhaust. IANAC, but it seems like that just exchanges one problem for another. I imagine that most, if not all, of the industrial processes that produce CO2 exhaust gases also result in other gases and particles getting into the exhaust stream, meaning tha…

You would, but more and more, CO2 is being regulated as a pollutant and there is going to have to be recovery from such waste gasses anyway.

Re: A way to make water potable using carbon dioxide

#12

Post by clort » Sun, May 21, 2017, 7:30 PM UTC

allannienhuis wrote: post #9

haneefmubarak wrote: post #6

> he imagines [the necessary CO2] would come from power stations and other industrial processes, such as cement-making, that produce the gas in large quantities as exhaust. IANAC, but it seems like that just exchanges one problem for another. I imagine that most, if not all, of the industrial processes that produce CO2 exhaust gases also result in other gases and particles getting into the exhaust stream, meaning tha…

I doubt they're suggesting they use the untreated flue gases as the gas in the apparatus. I think they're just pointing out that there are industrial sources of co2, n and that finding a use for the co2 helps with another pollution/waste issue

I don't think that this helps really with the pollution issue, since the CO2 is in effect being used as a catalyst and will be emitted afterwards just as it was before. What the article is saying though, is that a large consumer of cement (a high CO2 producing process) is also likely to be a large consumer of clean water.. so that leaves the process of cleaning the water CO2 neutral except for the small amount of power consumed

Re: A way to make water potable using carbon dioxide

#13

Post by grizzles » Sun, May 21, 2017, 7:31 PM UTC

haneefmubarak wrote: post #6

> he imagines [the necessary CO2] would come from power stations and other industrial processes, such as cement-making, that produce the gas in large quantities as exhaust. IANAC, but it seems like that just exchanges one problem for another. I imagine that most, if not all, of the industrial processes that produce CO2 exhaust gases also result in other gases and particles getting into the exhaust stream, meaning tha…

IANACE, but there are good reasons to sequester carbon emissions, and this scrubbing can be achieved with renewables (eg. solar thermal) for processes that involve heating the flue gas. The problem of course is that there isn't really an economic case for industry to do it, because the costs of implementing sequestration are quite capital intensive to polluters.

Re: A way to make water potable using carbon dioxide

#14

Post by mhb » Sun, May 21, 2017, 7:33 PM UTC

ChuckMcM wrote: post #10

Nice, other than the necessity of dumping CO2 into the air. I wonder if he tried creating an electric field across the water as some folks have done for desalination[1]. Any pollutant with a net positive or negative charge would be suitably diverted in that way. [1] https://cleantechnica.com/2013/06/30/desalination-with-small...

As to the necessary CO2, he imagines this would come from power stations and other industrial processes, such as cement-making, that produce the gas in large quantities as exhaust. This would restrict diffusiophoretic water plants to industrial cities—but, since such cities are huge sources of demand, that is hardly a problem.

Re: A way to make water potable using carbon dioxide

#15

Post by ChuckMcM » Sun, May 21, 2017, 7:49 PM UTC

mhb wrote: post #14

ChuckMcM wrote: post #10

Nice, other than the necessity of dumping CO2 into the air. I wonder if he tried creating an electric field across the water as some folks have done for desalination[1]. Any pollutant with a net positive or negative charge would be suitably diverted in that way. [1] https://cleantechnica.com/2013/06/30/desalination-with-small...

As to the necessary CO2, he imagines this would come from power stations and other industrial processes, such as cement-making, that produce the gas in large quantities as exhaust. This would restrict diffusiophoretic water plants to industrial cities—but, since such cities are huge sources of demand, that is hardly a problem.

I read that, but noted it suffers from 'scientist' blindness. These industrial processes, that are producing CO2 in large quantities, don't have an economical way to capture and cleanse that CO2 to allow for then shipping and selling it (or giving it) to this guy to clean water with it.

If they could capture the CO2 they could already resell it economically as there are lots of uses for it. There was some work in 2012 in Canada on that [1] but it hasn't gone well (here we are 5 years later and there aren't any products yet). There has been work on recapturing the CO2 in new plants, but that doesn't help our 'industrial cities' that are sitting on a bunch of existing infrastructure they cannot afford to refresh given they haven't fully depreciated the existing infrastructure.

[1] https://www.scientificamerican.com/article/can-co2-be-captur...

Re: A way to make water potable using carbon dioxide

#16

Post by mchannon » Sun, May 21, 2017, 8:07 PM UTC

Is this a breakthrough? Sure. But it's probably not a panacea.

* Getting actual salt particles out of flows of water is not what their experiment accomplished. They got larger particulates out of the water. The latter is quite easy to do, and the former quite difficult.

* Ionic charge is a very powerful driving force when what you're trying to move has a directionality to it, like a magnet picking up iron filings. This would work great for largely insoluble things like bacteria and mineral particles.

* When salts are dissolved, their constituent parts form ionic dipoles that will work far harder to stay together in solution. A little bit of ionic charge bias presents no challenge to a sodium chloride pair.

* CO2 use in this experiment may be close to zero. After CO2 is injected, it can be recovered and reused (at least in part). Finding a use for the petagrams of CO2 we're dumping in the air is a worthwhile goal but no matter how successful this technology may end up, it won't make a dent.

Re: A way to make water potable using carbon dioxide

#17

Post by ams6110 » Sun, May 21, 2017, 8:14 PM UTC

ChuckMcM wrote: post #15

mhb wrote: post #14

Earlier quoted context omitted.

As to the necessary CO2, he imagines this would come from power stations and other industrial processes, such as cement-making, that produce the gas in large quantities as exhaust. This would restrict diffusiophoretic water plants to industrial cities—but, since such cities are huge sources of demand, that is hardly a problem.

I read that, but noted it suffers from 'scientist' blindness. These industrial processes, that are producing CO2 in large quantities, don't have an economical way to capture and cleanse that CO2 to allow for then shipping and selling it (or giving it) to this guy to clean water with it. If they could capture the CO2 they could already resell it economically as there are lots of uses for it. There was some work in 201…

What is the current process for producing "pure" CO2 gas for sale e.g. as dry ice, or for use in food/beverage or for other industrial purposes? Unlike e.g. nitrogen or oxygen, concentrating it out of the atmosphere would seem to be inefficient as it's only roughly 0.04%.

Re: A way to make water potable using carbon dioxide

#18

Post by erikpukinskis » Sun, May 21, 2017, 9:15 PM UTC

mchannon wrote: post #16

Is this a breakthrough? Sure. But it's probably not a panacea. * Getting actual salt particles out of flows of water is not what their experiment accomplished. They got larger particulates out of the water. The latter is quite easy to do, and the former quite difficult. * Ionic charge is a very powerful driving force when what you're trying to move has a directionality to it, like a magnet picking up iron filings. Th…

Could you just use it on your sewer pipe? That would get us to a sustainable water system pretty fast.

Get off the grid: the sewer grid! Drink filtered shitwater, and top it off each week with a gallon of America's Best brand generic Spring Water Plus Shitwater Conditioner. Choose from Mountain Fresh, Country Home, and six other popular flavors!

(product may contain less than 1% of flourine, Nestlé brand product flavors, and other mind controlling food stuffs)

Re: A way to make water potable using carbon dioxide

#19

Post by hwillis » Sun, May 21, 2017, 9:41 PM UTC

ams6110 wrote: post #17

ChuckMcM wrote: post #15

Earlier quoted context omitted.

I read that, but noted it suffers from 'scientist' blindness. These industrial processes, that are producing CO2 in large quantities, don't have an economical way to capture and cleanse that CO2 to allow for then shipping and selling it (or giving it) to this guy to clean water with it. If they could capture the CO2 they could already resell it economically as there are lots of uses for it. There was some work in 201…

What is the current process for producing "pure" CO2 gas for sale e.g. as dry ice, or for use in food/beverage or for other industrial purposes? Unlike e.g. nitrogen or oxygen, concentrating it out of the atmosphere would seem to be inefficient as it's only roughly 0.04%.

Note that the gases coming out of a power plant are mostly nitrogen

Re: A way to make water potable using carbon dioxide

#20

Post by amelius » Sun, May 21, 2017, 9:55 PM UTC

mchannon wrote: post #16

Is this a breakthrough? Sure. But it's probably not a panacea. * Getting actual salt particles out of flows of water is not what their experiment accomplished. They got larger particulates out of the water. The latter is quite easy to do, and the former quite difficult. * Ionic charge is a very powerful driving force when what you're trying to move has a directionality to it, like a magnet picking up iron filings. Th…

> When salts are dissolved, their constituent parts form ionic dipoles that will work far harder to stay together in solution. A little bit of ionic charge bias presents no challenge to a sodium chloride pair.

An electric field of a few volts over a small channel seems to split this dipole just fine, [1].

[1] https://cleantechnica.com/2013/06/30/desalination-with-small...