Nanorust Used To Purify Water

eldavojohn writes "How do you remove arsenic from water? Well, a research team has discovered that adding and removing nanorust works well. From the article, 'The team added nanoscale iron oxide to contaminated water, where it clumped together with the arsenic. They then magnetized the nanoparticles with an electromagnet and pulled them out. "We only needed a surprisingly weak magnetic field," says Colvin. "In fact, we could pull then out with just a hand-held magnet, making this a very practical method.' Big news for developing nations that are plagued with non-potable drinking water."

Comments

Some potential, but there are better options

[Salvance]

This method sounds like it could eventually have some potential, but it's not like you'll be able to take water directly from the Ganges, add some nanorust, and have fresh sparkling drinking water. In developing nations, the key is ensuring factories and agriculture do not dump their waste into the drinking supply (one of the big problems in India), that the sewage and drinking systems are separated, and that modern filtration units are used. Implementing all of these would be far cheaper than having people boil their water, and would ensure that bacteria, lead, and other impurities are removed.

The article itself admits that nanorust is still too expensive to be used widely, while filtration units already exist that cheaply remove arsenic plus many other things cheaply. In the U.S., home filters (and even cheap Britas) remove 99% of all arsenic, along with similar levels of other chemicals and heavy metals ... so why spend tons of money making nanorust if something else already exists that is cheaper and just as effective?

Re:Some potential, but there are better options

[slughead]

In developing nations, the key is ensuring factories and agriculture do not dump their waste into the drinking supply (one of the big problems in India), that the sewage and drinking systems are separated, and that modern filtration units are used.

The main source of arsenic poisoning is and has always been from naturally-occurring sources in soil.

I remember when the international community paid millions of dollars to supply Bangladesh with wells to give them water. The problem was, the earth in that area is naturally rich in arsenic and it caused the single largest occurrence of arsenic poisoning in the history of man. Better than dying of thirst, I guess... or not.

Re:Some potential, but there are better options

[Salvance]

Arsenic is present naturally in the ground, but not nearly in the levels found in Bangladesh and India. All hypotheses that the well water pollution is a natural source have been discounted over the past 5-10 years, and all evidence (mostly gathered by British researchers) points to manmade arsenic sources (fertizer primirily) leaching into the ground water.

India and other countries have proposed massively expensive projects to contend with the disaster (which India still contends is not manmade, but that's because it's in their best interest to do so), but most of these do not address the issue that contaminated water is depositing arsenic into ground water stores and aquifers.

Re:Some potential, but there are better options

[Jeng]

quote: The article itself admits that nanorust is still too expensive to be used widely

Sounds like its not going to be long before an inexpensive method pops up.

quote: At the moment, the high cost of making nanoparticles means the trick is too expensive to be used widely. In principle, however, the nanoparticles are easy to make: the team created them by dissolving large pieces of rust in heated oleic acid, which can be found in ordinary olive oil.

"The temperatures needed are accessible in a frying pan," Colvin adds. "So we are now trying to develop a production method using ingredients and equipment that are available in poorer nations."

Re:Some potential, but there are better options

[reverseengineer]

Much of the arsenic contamination in South Asian water is of natural origin- a fact that a lot of well-meaning developmental organizations learned when they dug wells in Bangladesh. The options for water without arsenic in the region are getting it from rivers, which are becoming a much less attractive option as they are forced to support ever greater populations and industrialization, and from wells deep enough to get below arsenic-bearing sediments, which are much more expensive.

The problem with filtration is that it requires a level of centralized distribution that does not exist in many parts of the world. Either you do it from a central water treatment plant, which requires building an infrastructure of pipes and sewers, or you have to distribute filters directly to people. This makes those people dependent on their government (bad choice) or western aid agencies (really bad choice)for drinking water. The idea here is that a village could make these themselves.

I definitely agree, though, that acceptable waste disposal will become a necessity for clean water in developing nations, particularly as they become more developed. Stories of industrial waste dumped into rivers used for drinking and bathing, and of human waste trickling through open trenches down city streets sound primitive, sound foolish- until you note that the great cities of the West operated like that for centuries, and indeed the part about keeping agriculture and industrial waste out of drinking water is still an problem.

Re:Some potential, but there are better options

[Wills]

it's not like you'll be able to [...] add some nanorust, and have fresh sparkling drinking water. [...] the key is ensuring factories and agriculture do not dump their waste into the drinking supply (one of the big problems in India), that the sewage and drinking systems are separated, and that modern filtration units are used.

The history is that thousands of deep tube wells were constructed in Bangladesh with generous international funding and advice from various well-meaning organisations and governments around the world who wanted to help solve the problem of dangerous bacteriological contamination of drinking water supplies in the old shallow pit wells. For 10 years, lots of new tube wells were built all over the country at great expense. It was simply assumed that water supplies from these deep tube wells would automatically be safe to drink or use for irrigation because the water would be well filtered by the thick layers of sediments.

Unfortunately the deep sediments contained naturally occurring deposits of arsenic. Nobody realised this until local doctors noticed a large increase in arsenic-related health problems such as cancers, hair loss and skin lesions among young Bangladeshis. The drinking water from the tube wells was then tested and found to have dangerously high levels of arsenic. This arsenic contamination is caused by natural microbial degradation of peat, not by industrial pollution. Some people have unsuccessfully argued that the foreign experts involved in providing tube well advice in the 1990s were negligent in not having done any arsenic tests.

Because arsenic is cumulative and the local people have no alternative but to continue drinking the tube well water, the health problems from the arsenic are continuing to worsen and now affect over 13000 people. New more affordable arsenic filtration technologies are badly needed. Current technlogies are not practicable due to their very high maintenance costs.

Re:Some potential, but there are better options

[mnmn]

But you see its nice to know that on a camping trip, I can just scrape the rust off my car, put it in some water for some time, take it out with a magnet and drink it.

Anyone here knows if the body of a 93 Nissan Sentra has Mercury, Lead or anything bad?

Re:Some potential, but there are better options

[azhrei_fje]

Implementing all of these would be far cheaper than having people boil their water,

Not only that, but they might actually work. :) After all, boiling water isn't going to remove any of the heavy metals found in contaminated water. In fact, as the water boils off, the contaminates become more concentrated per measure of water.

Boiling water kills (most/some) germs and bacteria, but that's all.

Re:Some potential, but there are better options

[bmo]

"All hypotheses that the well water pollution is a natural source have been discounted over the past 5-10 years,"

Wrong.

Unless you've got a URL that disputes what this one says:

http://www.bgs.ac.uk/arsenic/bangladesh/reports.ht m

"13.1.4 Source of the arsenic

There is no doubt that the source of the As is natural, i.e., derived from 'ordinary' sediments by natural geochemical processes. The quantity of As present in groundwater (and adsorbed by the sediments) is simply too large to be derived from a discrete pollution source. Also its distribution across Bangladesh and West Bengal and with depth does not tally with a pollution source. There is also no need to postulate exceptional sources such as a particular mineralised area in the upstream catchment, as some workers have done for neighbouring West Bengal (Acharyya et al., 1999), although of course such areas may exist. This is one of the lessons that needs to be learned from the Bangladesh arsenic problem.

There is more than enough arsenic in most sediments to give rise to an As problem given the appropriate geochemical conditions for release and mobilisation. If all of the arsenic in a sediment containing 1mg As kg^-1 sediment dissolves in the groundwater, then the arsenic concentration would be 6000 micrograms/L or more, way above all drinking water standards. Both the average world and typical Bangladesh sediments contain several times this amount of arsenic. In other words, Bangladesh sediments do not appear to contain an exceptional amount of arsenic /in total/ yet give rise to exceptionally large groundwater arsenic concentrations. The high solid/solution ratio in aquifers and the great toxicity of arsenic mean that the contamination of groundwaters is sensitive to an imperceptible shift in the speciation of arsenic. A change of only a few percent in the partitioning of arsenic between sediment and water is sufficient to give rise to a significant groundwater arsenic problem."

So unless you've got some sort of documentation that trumps the British Geological Survey, I suggest you take a course in "rocks for jocks" (geology 101) instead of spewing your uninformed twaddle here.

--
BMO

Wonderful

[Anonymous Coward]

but you might get even more results with picorust.

Ounce of prevention?

[Mateo_LeFou]

question one should be How Did the Arsenic Get In There?

Is this a normal geological property or result of pollution?

Re:Ounce of prevention?

[k31bang]

ummmm perhaps it was there naturally? From http://www.nrdc.org/water/drinking/qarsenic.asp:

"5. How does arsenic get into water supplies?

Most arsenic enters water supplies either from natural deposits in the earth or from industrial and agricultural pollution. Arsenic is a natural element of the earth's crust. It is used in industry and agriculture, and for other purposes. It also is a byproduct of copper smelting, mining and coal burning. U.S. industries release thousands of pounds of arsenic into the environment every year."

Re:Ounce of prevention?

[Five Bucks!]

Arsenic is a common contaminant of surface water supplies that occurs naturally. Often times a source is so contaminated by natural arsenic that the source has to be abandoned.

Generally, arsenic is not the most important contaminant in drinking water. In fact, chlorination of surface water often results in contaminants that are worse than what's in the raw water. Trihalomethanes (THMs) http://en.wikipedia.org/wiki/Trihalomethane are formed from a reaction of free chlorine and organic compounds.

This nanorust process would probably have wider application in treatment of industrial wastewater rather than drinking water.

Re:Ounce of prevention?

[lawpoop]

It is a normal geologic property.

Re:Ounce of prevention?

[Salvance]

Many people (particularly those with an interest in hiding India's massive contamination crisis) will claim that it's natural. In India and Bangladest though, this just isn't true. In these countries, all evidence shows that it's because of manmade contamination. Prior to the 1960's, British researchers found no evidence of high arsenic levels in either shallow or deep wells. By 2000 though, there were very high deposits that had been left by industrial and agricultural runoff.

Re:Ounce of prevention?

[AB3A]

If you had actually read your very own link to Wikipedia, you'd see the following:

The THMs produced may have adverse health effects at high concentrations, and many governments set limits on the amount permissible in drinking water.

I'm sorry, THMs are not good for you, I'll agree with you there. However, compared to Arsenic, I'll take the THMs every time. Oh, and by the way, I work for a water utility. THMs are not easy to deal with. Chlorination works very well for sanitizing water. The alternatives are Ozone, and UV. Both have their downsides. Chlorine is cheap. Chlorine has a residual which can make it useful when the water may have to sit in the distribution system for a while. The other two methods are good for sanitizing the water, but not for keeping it fresh.

At some low, yet to be determined, level THMs are probably not a threat. Please don't spread FUD about it. The real problem is serious enough without misinformation such as you presented.

Re:Ounce of prevention?

[Five Bucks!]

Except for the fact that you're a vindictive water utility worker, you're also correct. THMs are likely less harmful than Arsenic in your water, if Arsenic is present in measurable quantities at all.

My argument is that it's like worrying about dieing from ebola virus when the common cold is much more likely to take your life. That's all. You may now dismount from your high horse.

*sigh*

[Ant P.]

So what's wrong with calling it something like "microscopically fine rust powder", or something else that doesn't reek of marketing buzzwords?

Re:*sigh*

[teknognome]

Nanorust is shorter ;)

Re:*sigh*

[scotch]

Don't you mean "nanoscopically fine rust powder"?

Re:*sigh*

[AWeishaupt]

That would be *milli*scopic, would it not?

Re:*sigh*

[Goldsmith]

Right!

Can we save the prefix "nano" for when it is scientifically appropriate? Nanorust is the kind of word you throw around at an internal group meeting to be cute, but it shouldn't find it's way into a publication.

I would be fine with iron-oxide nanoparticles, or even rust nanoparticles, but there are plenty of perfectly good non-scientifically-embarassing names for this stuff such as simply iron-oxide clusters.

Re:*sigh*

[Ant P.]

I suppose a better name for it would just be "rust ground up into molecules".

Re:*sigh*

[mspohr]

... because they are using nano-sized particles.

Re:*sigh*

[MBC1977]

Two reasons I can think of off the top of my head: (1) microscopically fine rust powder sounds geeky to the average reader, while nanorust sounds cool, and (2) who wants to actually spout microscopically fine rust powder, when it can be shortened to nanorust?

Granted it does sound like a buzzword, be even as a geek, I'd hate to have to say all of that, when ironically enough, nanorust actually would make sense to me. (disclaimer, I am a both a double major in business admin (marketing concentration) and computer science), so I can see both sides of the arguement here.

One other thing to think of, as it just came to mind... to capture (meaning get them interested) a venture capitalist or even the future generation of scientists (meaning the children), you gotta make it sound simple now days. A lot of smart people are turned off if it sounds too technical, (one of the reasons I believe a lot of children who are good at math -- I'm using my daughter for instance, is great at math, but gets frustrated because of the technical terminology (she always who came up with these stinking terms), whereas if its broken down to sound simple, then they understand it better and can do the work without complaint.

I didn't mean to go on diatribe, but I think that is the problem with a lot of professionals (be it computer geek, business geek, etc.) If its made simple, people will get interested enough to continue. Kinda like hammering a nail with w sledgehammer, its overkill.

Regards,

MBC1977,
(US Marine, College Student, and Proud Parent!)

Re:*sigh*

[Xiph1980]

Well, atleast they didn't call it iPurify thru the addition, and removal of iRust (which is achieved thru iOxygenating iIron)

Re:*sigh*

[nospam007]

>..Can these iron oxide particles be individually seen with a microscope?
Obviously only with a nanoscope, dummy!

Re:*sigh*

[slowbad]

Even a phrase as you suggested is going to be reduced to a marketing buzzword by way of acronymns -- in your case, MFRD.

Going to toxic areas is deserving of bomb squad status, "Move outta the way people; make way for the Heavy Metal Removal Unit!"

Re:*sigh*

[r3m0t]

No, he meant that nano was 10^-3 times smaller than microscopic.

Re:*sigh*

[noidentity]

Yeah, but will this nanoscope be visible under a microscope?

Re:*sigh*

[InadequateCamel]

Dumbing down scientific language does nothing to help the progression and advancement of science. Terms like "nanorust" make people think it is sonething really complicated and technological, but when they find out that it's just small rust pieces and that it ISN'T cool at all it just feeds the idea that scientists are liars and smart-asses. We chemists in particular have a bad enough public perception (despite the fact that without chemists our curent way of life simply would not exist...) without this buzzword nonsense. THere are many more interesting (and less dishonest) ways of making science appealing to others; chemistry is full of neat tricks and displays. Let's not make the scientific discourse dumber simply to attract a half-dozen more kids.

Re:*sigh*

[Vicsun]

The fact that it's not microscopically fine, which would imply particle sizes in the 'micro' range.

Re:*sigh*

[epine]

Why do we give credence to what Joe-average expects nano to convey? The fact of the matter is that there is a huge domain of biological phenomena operating at the micro scale, and another huge domain of physical chemistry operating at the nano scale, neither of which should evoke gasps of "Oh, cool!"

It's a mugs game to invest energy in controlling the impressions/reactions of the non-thinking masses. Why was nano cool in the first place? Because you could eat a small machine? Oh, cool.

Re:*sigh*

[dr. loser]

Because the nanoparticles are, in fact, nanoparticles. 12 nm in diameter, and 4 nm in diameter later in the paper. Indeed, that's critical for why this works.

Re:*sigh*

[LunaticTippy]

The ipod nano must really piss you off. It's totally visible with the naked eye!

A case of "nano" for its own sake...

[pla]

Removing arsenic from water does NOT require "nano" rust. Plain ordinary sand-grain-sized rust flakes will do just fine. Humans have used this "tech" for at least hundreds, if not thousands, of years, to purify water.

As the two biggest problems, though - Too much iron causes problems in humans (males in particular, and yes, for the obvious reason); and the non-water product of this technique consists of a rather toxic arsenic sludge which you occasionally need to dispose of somewhere that won't run right back into your water source.

Re:A case of "nano" for its own sake...

[Dilpo]

Read the article next time, no where in it does it say it requires nanorust, its just simply more efficient. From the article itself "One kilogram of nanorust has the same surface area as a football field," says Colvin. "Basically, you can treat a whole lot more arsenic with less material."

Re:A case of "nano" for its own sake...

[the eric conspiracy]

It's still not a particularly wonderful idea. The best way of handling this sort of process is use of a microporous material like zeolites, ion exchange resins and so on. You still get an extremely high specific surface area - zeolites typically have areas on the order of 50 m^2 / g, which is about 10x the area claimed for the nanorust. Ion exchange resins can get up to 500 m^2 per gm (100x the nanorust). These materials because of their size can be separated using physcal processes (less capital intensive) and regenerated for reuse. In some cases they can be used in flow through systems so separation is not needed.

Re:A case of "nano" for its own sake...

[John Hasler]

> The best way of handling this sort of process is use of a microporous material
> like zeolites, ion exchange resins and so on.

So tell me where to buy inexpensive zeolites, ion exchange resins and so on suitable for removing arsenic.

Re:A case of "nano" for its own sake...

[the eric conspiracy]

The same place you buy inexpensive nanorust.

i.e. nowhere.

Re:nanoscale

[Anonymous Coward]

wiki: "Iron(III) oxide is often used in magnetic storage, for example in the magnetic layer of floppy disks"
I should have known that. . .

Third World Countries?

[/dev/trash]

I know of 5 or 6 towns in my own COUNTY that need this.

Re:Third World Countries?

[dennison_uy]

If you read carefully, the parent poster is implying that he is living in the U.S. in an effort to point out that developed nations can also benefit from the technique and not just "developing nations" as the story suggests, which I agree with. I am not familiar with other purifying methods but the article seems to suggests that this is the "cheap" alternative which may be a good enough reason to switch if it provides comparable results to other methods.

Re:Third World Countries?

[cicadia]

If you read carefully, you'll see that the parent post to yours never said anything about a third world country :)

Re:nanoscale

[dapsychous]

Any random rusting object (abundant in most developing nations) and a REEEAAAAALLLYYYY tiny file.

Re:Activated carbon?

[Five Bucks!]

Activated Carbon is best utilized in removing large organic molecules.

Removing ions in water is best done through reverse osmosis. It can also be accomplished - to a small extent - using coagulants such as Ferrous Chloride or Aluminum Sulfate.

Please read before paste-bombing.

[Mateo_LeFou]

I don't mean to be a dick, but the first sentence there ("Most arsenic enters water supplies either from natural deposits in the earth or from industrial and agricultural pollution") can be summarized as "some is natural and some is from pollution", which gets us nowhere until some *ratio between the two is asserted...

Is Hawaii a third world?

[Anonymous Coward]

Arsenic occurs naturally in volcanic rocks in Hawaii. However arsenic compound was used by white man as a herbicide on sugar plantations. Now Hawaii has a 10x more arsenic than naturally occurring in rocks. In fact some of the new hosing developments have to remove topsoil to be within (Hawaii relaxed) EPA standards.

Arsenic is insoluble so it just stays in ground or gets washed away. That's why coral-reef fish and algae's are usually contaminated the most.

lined nanotubes

[realchimera]

This is not new technology at all. Some professors i know opened a company using the lined carbon nanotubes to do the same thing around 5 years ago.

r&r

[robinesque]

I think the really interesting part of this research is not what they say they are doing with it now--it's what could potentially come of this. I don't know what it might be useful for, but knowing that can we now do this might help us in some other area at some other point in time.

Re:Better Solution

[i kan reed]

While I agree with the principle of what you're stating, it's not like arsenic is being created in mesurable quantities. An element is an element and stays the same one as long as no nuclear reactions are involved. So unless it's being introduced into water supplies where before it was buried safely somewhere, it's just a natural contaminant.

The question becomes...

[camperdave]

Where are you going to get all the nano-cars needed to generate this rust?

that's simple ;) your trycorder is out of date!

[freaker_TuC]

Your version of your trycorder is just too big, telephones are smaller than ever, they already got small and micro dominated too. You better hail to your overlords defining what nano really is, else you won't get a nanostep further in this Star Trek universe where the primary directive might be a solution ....

Re:first world is no better

[Dr. Smeegee]

All too true. For years I had planned on making a couple of "bug-out bags" for my spouse and I to keep in our cars and one for the house. The bags would contain light sleeping bags, batteries, crank lights and radios, "Iron Rations" several rolls of quarters, some spending cash, bottle of bleach, "dog antibiotics", phone numbers of all and sundry and brace of water purification tablets and hiker-style filtration systems. When the planes hit the towers I was forcibly reminded and resolved to gather the needed items ... and again when Katrina hit ... and I have about half of it. :-/

I live in a flood zone (my house was in up to the second story in 1937), and yet without the terror looming over on me, the sensible, simple preparations keep getting pushed to the back of the burner.

I paid $6.00 for breakfast at Hardees this morning. I could have bought almost a weeks worth of water purification tablets for that.

Re:first world is no better

[Dr. Smeegee]

back of the burner == back burner. I should have done a read of the post, firstwise.

Arsenic -- is it really so bad?

[poochNik]

Of course it is, but in small doses it was used in the past as a stimulant. It was also used topically (way before Retin A) to clear up one's skin and to gain that dead white skin look that fashion sometimes decrees--usually, however, while still living.

Putting it into different units

[dbIII]

"One kilogram of nanorust has the same surface area as a football field,"

Not only that - you can make it out of Volkswagens!

Non-potable?

[liak12345]

Big news for developing nations that are plagued with non-potable drinking water."

All you need is a bucket or a sealable cup and you can carry it around. That's potable enough for me!

Re:Non-potable?

[Garrett Pennell]

You're thinking of "portable," noob.

Re:Non-potable?

[liak12345]

Well I thought it was funny.

Re:Non-potable?

[Garrett Pennell]

I know, I was just kidding. :)

Its a matter of taste, really:

[Upaut]

Personally, I always add an iodine tablet to my drinking water. Be it purified, distilled, distilled/deionized, treated with chlorine, you name it, I always add it. I grew use to the taste of iodine, and I associate the taste with safe water... Now I admit that this system seems great, and highly cool, but without that taste myself, and a lot of others, really will not trust the water....

Oh, if anyone knows if I am slowly killing myself by doing this, please tell me....

Re:Its a matter of taste, really:

[joto]

Uhmm, yes. You are slowly killing yourself by doing this. Iodine tablets are intended as a temporary solution, such as during a disaster, camping trip, etc... It's not considered healthy to use them all your life. One producer, potable aqua, recommends that "extended daily use should not exceed six weeks". This limit is of course totally arbitrary and highly conservative, and most likely safe to exceed, but I assume they put it in their brochures for a reason. Research is scarce, and it may turn out that iodine tablets is safe after all, but personally, I wouldn't take the risk. If I were you, and I lived somewhere where I needed to filter my water, I would probably search for a healthier long-term alternative than iodine tablets.

Re:There is an easier way..

[RobertLTux]

im sure you are just baiting folks but what happens if that "pure water source is a 4 day walk in 100+ heat?

answer you will be a rotting corpse a daya away from the water

Distillation

[Archeopteryx]

You can easily boil water with a few steel mirrors. Distillation removes not only organic but inorganic pollutants, and renders the water sterile.

The only thing that distillation cannot deal with is the few volatile organic molecules that have a boiling point near that of water, and a charcoal filtration step on the condensate will deal with those.

Where electricity is available, a gallon of distilled water can be prepared with two kilowatt hours of energy, at a cost in most places of under sixty cents.

You can even get stovetop distillers.

Re:Distillation

[joto]

No. You can't easily boil water with a few steel mirrors. It's possible, but it's not easy.

The "few volatile organic molecules" may contain such things as insect pesticide, oil and gasoline spill, etc...

In addition to the cost of electricity, you must also include the cost of water. To produce one liter distilled water, requires several liters of water (I've seen 5 liters claimed, although I haven't seen much justification for this number).

And finally, distilled water is not healthy. It's acidic and lacks minerals. Unless you really need to remove all inorganic pollutants, it would be better to just boil it.

Re:Distillation

[Archeopteryx]

Actually, you are incorrect about most of this;

1. Yes, it is easy if the boiling apparatus is designed correctly. I've done it. And you can distill water without actually boiling it, though it is a slower process. And it is under active development; http://www.solarconference.net/abstract_selection. php http://www.ecozen.com/steam1.htm http://www.epsea.org/stills.html http://www.solaqua.com/solwatdis1.html http://www.fsec.ucf.edu/pubs/EnergyNotes/en-3.htm
2. The volatiles that come out at water boiling temperature are usually relatively benign, and as I said, a coconut hull carbon stage removes them.
3. My home distillation device wastes only about 1% of the water you put into it. It uses air to cool and condense the steam, so no flow of cool water is required at all.
4. Distilled water is not acidic at all. I just tested mine. Totally neutral, pH 7. That is by definition, as distilled water is what is used to calibrate the middle of the scale. And the lack of minerals is not a deficit to the healthiness of the water at all. You would have to drink many gallons of water every day to get even 1% of any of the important minerals. In other words, you get these from your food, and the contribution of the water is insignificant. Add to that the fact that minerals can include things like Arsenic, Lead, Mercury, Uranium, and other things that are bad for you even in trace amounts.

Finally, some people say that distilled water tastes funny. But the taste of water is governed by the amount of oxygen in the water, and fresh distilled water very much lacks oxygen. This can be remedied by filling a container half full of water and shaking vigorously.

The technique has already been commercialized

[517714]

http://polymetallix.com/

They have far more details than the article.

Old method maybe?

[slidersv]

I think we used similar method around the end of the 80s, when we really couldn't trust the water authorities. I'm really not sure how it worked, but the method consisted of inserting two metal rods in the 5-liter canister, which then rusted and attracted rust particles between each other. The particles that didn't make it to the other rod fell onto the bottom. After about 2 days, the rods were pulled out, and the water was ready to drink, except for perhaps the last liter, which had a bit reddish color from rust.
I recall this mechanism was used by many, since the water quality was questionable, and no one wanted to get sick.

Nanotech Desalination?

[Garrett Fox]

Is there any knowledge out there about obtaining desalinated water using some sort of nanotech filter, other than the high-pressure blasting method used today?

Old wisdom, new application

[vogon jeltz]

"Rust" has been in use as a catalyser in chemical reactions for ages. One of the better known ones is probably the synthesis of ammonia on an industrial scale aka "Haber-Bosch-synthesis", developed in the early 20th century. And this new application has promise.

I don't want to get off on a rant here

[rantingkitten]

But god, do I ever hate the word "potable". It sounds like a hayseed trying to say "portable": "Them big ol' buckets uh water'r too heavy t'be po'table!"

The word has one and only one meaning: "drinkable". It has no distinction from this definition, either, unlike most other synonyms in the English language which at least have some nuance of meaning distinct from other words. So, would someone tell me why anyone would insist on using the word "potable" instead of "drinkable", particularly in such cases as this where both words are used?

Re:There is an easier way..

[kbox]

Right, Because poeple who live 4 days away from water have loads of nanorust....

The difference between potable and drinkable

[patio11]

Water from the Hudson may be drinkable, but it is not potable. Water from the Chicago River is neither. Honestly, when they dump the food coloring into the Chicago River on St. Patrick's Day and it goes radioactive green for miles around it looks more appetizing than it does at any other point in the year -- the color and consistency of lime jello!

Normally I'm all for Darwinism...

[Saikik]

IANAD(doctor) but..

" Excess iodine has symptoms similar to those of iodine deficiency. Commonly encountered symptoms are abnormal growth of the thyroid gland and disorders in functioning and growth of the organism as a whole. Elemental iodine, I2, is deadly poison if taken in larger amounts; if 2-3 grams of it is consumed, it is fatal to humans. Iodides are similar in toxicity to bromides."

Toxicity of Iodine

I always assumed the iodine they add to salts were good enough to cover the population base (US) from iodine deficiency.

Isn't that just rouge?

[RockModeNick]

Aren't nanoparticles of iron oxide simply jewler's rouge, the same stuff used for brightening gold and silver and in the final polish stages of harder materials?