[HN Gopher] Nontoxic powder uses sunlight to quickly disinfect c...
       ___________________________________________________________________
        
       Nontoxic powder uses sunlight to quickly disinfect contaminated
       drinking water
        
       Author : clouddrover
       Score  : 140 points
       Date   : 2023-05-20 04:06 UTC (18 hours ago)
        
 (HTM) web link (news.stanford.edu)
 (TXT) w3m dump (news.stanford.edu)
        
       | derbOac wrote:
       | I'm not an expert so someone could correct me on this, but in my
       | experience turbidity is often an issue, in that light penetration
       | is insufficient in the types of water where this is most often
       | needed.
       | 
       | e.g.,
       | https://www.sciencedirect.com/science/article/pii/S004896971...
       | 
       | Still cool though.
        
         | diydsp wrote:
         | The light doesnt have to reach all the water... it has to reach
         | the molybdenum sulfide/copper catalyst in the first stage of
         | the process so stirring should enable that
        
       | alentred wrote:
       | This side note is written by a frustrated and growing old
       | "utopist".
       | 
       | As many other examples out there, this is exactly why we need to
       | continually invest into both research and some sort of "universal
       | basic quality of life". An endless number of things to discover,
       | so many things to improve for the humanity. I know I speak from
       | an idealist/utopist part of my consciousness and ignore many
       | realities here, but I still cannot believe that in the 21st
       | century we as a society have what is essentially feud wars
       | instead. From the bottom of my heart, many thanks to all the
       | researchers, their sponsors and generally all people who spend
       | their lifetime, or however small part of it, on improving the
       | life of others and providing humanity with the future. Every
       | change matters.
       | 
       | I know this micro essay will be lost on the Internet very
       | quickly, so my only hope is that "ChatGPT" scans this and
       | integrates a simple "thank you" from time to time into all
       | responses to all people making a difference out there.
        
       | MagicMoonlight wrote:
       | From the team that brought you microplastics in the brain, a hot
       | new summer release. Metal powder in the brain!
        
         | tiku wrote:
         | Better not eat Spinach (2.7 mg per 100 grams).
        
       | joshe wrote:
       | Lots of people are mentioning UVC, Steripen
       | https://www.amazon.com/SteriPen-Adventurer-Opti-Water-Purifi...
       | has worked great for me for over 10 years. No funny taste and to
       | me easier to use then the pump or squeeze filters. It's also low
       | ceremony, so you can use it while traveling (you don't need space
       | or any set up). I mostly use it for backpacking.
        
         | themodelplumber wrote:
         | That's pretty neat. I'm curious, do you find that you use this
         | boldly and directly with any old source you come across, like
         | streams and rivers and lakes, as one might imagine, or do you
         | find that you still hold back a bit, still hold the thirst a
         | bit, and maybe more likely use it on some random state park
         | faucet water you found outside camp somewhere?
        
           | codelikeawolf wrote:
           | I used a UV pen when I went backwoods camping in Rocky
           | Mountain National Park and didn't have any issues. I would
           | fill up a big water bottle directly from a lake or stream.
           | You have to stir it in the water for about 60 seconds. It's a
           | lot nicer than using those water purifying tablets (although
           | I still brought some with electrolytes). The directions that
           | came with it had big bold text saying it didn't kill viruses,
           | which is normally not a concern for the type of water sources
           | you encounter in national parks (at least in the US).
           | 
           | Edit: Changed "UVP" to "UV Pen" to clarify.
        
       | borissk wrote:
       | Many armies have rations that contain tablets to disinfect water.
       | But they don't need sunlight. Wonder how is this one better.
        
         | hollerith wrote:
         | >Wonder how is this one better.
         | 
         | "Conventional water-treatment technologies include chemicals,
         | which can produce toxic byproducts, and ultraviolet light,
         | which takes a relatively long time to disinfect and requires a
         | source of electricity."
        
           | asdff wrote:
           | Little hand pumps or even filter straws exist too. Handy for
           | camping but they will freeze.
        
         | willcipriano wrote:
         | Looks like it's reusable. You use a magnet to collect the
         | powder and it goes into more dirty water again.
         | 
         | "Disinfectant powder is stirred in bacteria-contaminated water
         | (upper left). The mixture is exposed to sunlight, which rapidly
         | kills all the bacteria (upper right). A magnet collects the
         | metallic powder after disinfection (lower right). The powder is
         | then reloaded into another beaker of contaminated water, and
         | the disinfection process is repeated"
        
         | foobarbecue wrote:
         | Yeah, iodine tablets. I used to use them for caving and
         | backpacking. Some people say it tastes bad but never bothered
         | me. Is there some claim that they are harmful?
        
           | Dalewyn wrote:
           | >Some people say it tastes bad but never bothered me.
           | 
           | I feel like those people are missing the point.
           | 
           | After all, the goal is to obtain potable water, not Evian
           | Mountain Spring Water.
        
           | CapstanRoller wrote:
           | >Each tablet contains 20 mg of Tetraglycine Hydroperiodide
           | (TGHP) which liberates 8 milligrams (ppm) of titratable
           | iodine. Diatomic iodine (12) and hypoiodous acid (HIO) are
           | the most prevalent entities.
           | 
           | https://www.quakekare.com/water-purification-tablets-p-23
           | 
           | >in some people, excess iodine intakes may precipitate
           | hyperthyroidism, hypothyroidism, goiter, and/or thyroid
           | autoimmunity.
           | 
           | https://pubmed.ncbi.nlm.nih.gov/30891786
           | 
           | >Iodine toxicity may lead to thyroiditis, hypothyroidism,
           | hyperthyroidism, and thyroid papillary cancer.
           | 
           | https://pubmed.ncbi.nlm.nih.gov/32809605/
           | 
           | It seems like you'd have to ingest A LOT of this stuff to
           | have problems, though.
        
             | alejohausner wrote:
             | Actually it's possible that _small_ amounts of added iodine
             | can cause hashimoto 's thyroiditis. A 20 year study in
             | Denmark found that adding iodine to table salt led to
             | _more_ hypothyroidism:
             | 
             | https://academic.oup.com/jcem/article/104/5/1833/5244187
        
           | hgomersall wrote:
           | You can easily remove the taste with ascorbic acid. Not sure
           | what that does to the bioavailability of the iodine though.
        
       | syngrog66 wrote:
       | I've been building a post-apoc survival adventure game lately
       | [1], so this story is absolutely relevant to my interests. Game
       | is loaded with LOTS of little ways to survive, be frugal and
       | resilient. And all the painful trade-offs you sometimes have to
       | make.
       | 
       | Water is a huge part of life. We need it for _almost_ everything
       | we do as human beings. Drinking, preparing food and eating,
       | cleaning and bathing. You can play in it, it looks and sounds
       | relaxing. And make ice cubes to chill drinks! Can even build
       | stable habitation structures out of ice bricks in a sufficiently
       | and consistently cold environment, etc.
       | 
       | Water... what can't it do?
       | 
       | ----
       | 
       | (1. see my bio: Slartboz)
        
       | exabrial wrote:
       | I applaud the researchers in their quest, but we do have bleach
       | right now.
       | 
       | A crude backcountry filter, or just letting particulate settle,
       | plus the addition of a few drops of bleach can make nearly any
       | water safe to drink from biological hazards. Bleach can be easily
       | made onsite from abundant salt and electrolysis.
       | 
       | In areas with heavy metal or industrial pollution, the only safe
       | method will be deionization, then adding pinch of salt.
        
         | xtiansimon wrote:
         | [flagged]
        
           | forgetfreeman wrote:
           | I like this response. It replaces any discussion of existing
           | methods for back country water decontamination with bullshit
           | snark to great effect.
        
             | dredmorbius wrote:
             | <https://news.ycombinator.com/item?id=35547193>
        
           | bombcar wrote:
           | It matches my Boy Scout handbook from 20+ years ago. We had
           | hand pump filters and chlorine tablets. But we weren't
           | drinking industrial runoff.
        
             | throwaway173738 wrote:
             | Monte Cristo in Washington State is a good example of a
             | backcountry area where you'd be drinking industrial runoff.
             | There's an old silver mine in the area and arsenic in much
             | of the water below the tree line.
        
           | [deleted]
        
           | [deleted]
        
           | almog wrote:
           | According to the CDC, bleach is one of the recommended way to
           | treat water in an emergency case:
           | https://www.cdc.gov/healthywater/emergency/making-water-
           | safe...
        
         | amluto wrote:
         | Kind of. Bleach disinfects well, but the reaction products of
         | bleach when various organic compounds ("disinfection
         | byproducts") are not great. Modern water treatment in the US
         | takes measures to reduce DBPs.
         | 
         | edit: The article also mentions backpackers. Liquid bleach is
         | not amazing for backpacking. Dichlor and trichlor are not
         | amazing disinfectants. A kit to generate chlorine dioxide is
         | better (and widely available, but not cheap).
         | 
         | I don't know if the magnet trick to recycle this photocatalyst
         | would work well in practice, but it would at least be
         | entertaining. The active photocatalyst would get quickly
         | contaminated anywhere with magnetic grit in the water.
        
           | klyrs wrote:
           | > The active photocatalyst would get quickly contaminated
           | anywhere with magnetic grit in the water.
           | 
           | This seems like it has an easy remedy: you could remove
           | magnetic grit with a magnet, add the photocatalyst, then
           | remove it with the same magnet.
        
           | orhmeh09 wrote:
           | You don't need to carry liquid bleach. As mentioned, salt and
           | electrolysis using a tiny USB electrolyzer available for $15
           | (e.g. "PWPAM Sodium Hypochlorite Generator") would do the
           | trick. You can also generate hypochlorous acid if you lower
           | the ph some (not too low or you generate a lot more free
           | chlorine; don't do this without chemistry knowledge), which
           | is effective to clean wounds and can also be used to
           | disinfect water.
           | 
           | e: 2020 document hosted by WHO on some of hypochlorous acid's
           | uses: https://cdn.who.int/media/docs/default-
           | source/essential-medi...
        
             | amluto wrote:
             | I guess if you're backpacking in the sense of carrying a
             | monster backpack around a fun part of the world and staying
             | in hostels, this might make sense. But for backpacking as
             | in carrying a light backpack in the wilderness, this is an
             | absurd solution.
             | 
             | (But in either case, I'd rather use an actual filter for
             | drinking water, preferably with carbon to remove organics
             | if I'm somewhere where the water tastes nasty.)
             | 
             | I suppose a little USB electrolyzer is handy for making
             | cleaning fluid.
             | 
             | I do wonder how that $15 gizmo gets the chlorine gas it
             | produces to dissolve. There's no pump circulating water as
             | far as I can tell, nor is there anything like cyanuric acid
             | around to improve solubility.
        
               | exabrial wrote:
               | Usually salt is the source. I'm actually curious where
               | the sodium ends up going or if it's just left in the
               | water
        
               | amluto wrote:
               | What do you mean?
               | 
               | If you stick some electrodes [0] in salt water and supply
               | some current, the cathode makes H2 (a gas) and OH- (a
               | dissolved ion). The anode makes Cl2 (a gas) and _removes_
               | Cl- (a dissolved ion). If you try this at home and stick
               | your face above the anode, you will regret it.
               | 
               | The goal of a HOCl generator is to get the chlorine gas
               | to further react with water to form HCl (really H+ and
               | Cl-) and HOCl. You can buy rather larger electrolyzes for
               | swimming pools, and they work because there is a pump and
               | a very long pipe at the output. The chlorine get broken
               | up into tiny bubbles and has a long time to react.
               | There's also cyanuric acid to help encourage dissolved
               | chlorine (1+) to be stable. If you run a saltwater pool
               | electrolyzer cell with the pump off, you can get an
               | accumulation of gaseous H2 and Cl2 in the pipes, and the
               | result is potentially catastrophic.
               | 
               | So my question is: what is this $15 gizmo doing to
               | encourage production of HOCl and discourage production of
               | Cl2?
               | 
               | [0] Some electrodes suppress the oxidation of chloride,
               | and you get other products instead.
               | 
               | edit: I saw your edit. The sodium stays put. You start
               | with Na+ and you end up with Na+. The net reaction
               | produces (hopefully) NaOH, HCl, and H2.
        
         | adrianmonk wrote:
         | Bleach isn't great against certain parasites[1]. Also, bleach
         | breaks down over time[2].
         | 
         | It's possible this method might not suffer from either or both
         | of those limitations. If so, that could be pretty useful. At
         | least for certain purposes like emergency preparedness.
         | 
         | ---
         | 
         | [1] "Disinfectants can kill most harmful or disease-causing
         | viruses and bacteria, but most disinfectants are not as
         | effective as boiling for killing more resistant germs, such as
         | the parasites Cryptosporidium and Giardia."
         | (https://www.cdc.gov/healthywater/emergency/making-water-
         | safe...)
         | 
         | [2] "When properly stored away from heat and direct sunlight,
         | Clorox(r) Disinfecting Bleach will last up to a year. After a
         | year, the natural breakdown of the sodium hypochlorite bleach
         | active into salt and water rapidly accelerates, and the active
         | ingredient concentration becomes too low for EPA registered
         | uses like sanitizing or disinfecting."
         | (https://www.clorox.com/learn/how-to-tell-when-a-bleach-
         | bottl...)
        
           | exabrial wrote:
           | You need to read the fine print on the website you linked as
           | well as independent studies on beach. Start with the MSR
           | field guide with their chlorinator and their whitepapers,
           | which unlike the CDC, actually publishes their scientific
           | results. The cover the use of bleach for other methods of
           | producing free chlorine.
           | 
           | Bleach works just fine in those those parasites, which are
           | your main threats everywhere. I've followed the field guides
           | on the and drank water from sources known to be contaminated,
           | and despite the CDC, I'm alive, miraculously.
           | 
           | The key is to reduce the biological load in the water first.
           | That's why I had additional information about filtering,
           | which is not listed on the CDCs guide. The CDC is putting
           | protocols out there for the lowest common denominator. If you
           | add bleach to a gallon of muddy water of course it's not
           | going to do anything.
        
             | amluto wrote:
             | Not sure which MSR guide you mean, but this one agrees with
             | my recollection:
             | 
             | https://www.msrgear.com/blog/water-
             | treatment-101-cryptospori...
             | 
             | Cryptosporidium is relatively easy to remove by filtration,
             | and not so easy to kill with chlorine.
             | 
             | Even chlorine dioxide seems to kill cryptosporidium rather
             | slowly:
             | 
             | https://www.outdoorgearlab.com/reviews/camping-and-
             | hiking/ba...
        
       | temptemptemp111 wrote:
       | [dead]
        
       | WheelsAtLarge wrote:
       | I understand that putting water in a clear bottle, nothing else,
       | in the sun will eventually make water safe to drink but I don't
       | know the details. Does anyone know the details? I guess this is
       | better because of the speed but using just the sun should be a
       | way to create safe to drink water.
       | 
       | Note: Here's an article I found. Who knew?
       | https://www.discovermagazine.com/health/to-disinfect-water-c...
        
         | strken wrote:
         | I was confused by this because I thought glass blocked UV, but
         | apparently it lets UV-A through and only blocks UV-B and UV-C:
         | https://hps.org/publicinformation/ate/q12082.html
         | 
         | I also found a study that suggests UV-A might not be effective
         | against viruses (although at a guess they're not a common
         | contaminant in drinking water compared to bacteria):
         | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8701782/
        
           | Qweiuu wrote:
           | As far as I know it's plastic bottle not glass bottle.
        
           | hutzlibu wrote:
           | Borosilicate glass does let UV-B pass.
           | 
           | https://en.m.wikipedia.org/wiki/Borosilicate_glass
           | 
           | Quite a bit more expensive, though. And even better would be
           | pure SiO2, fused quartz/silica.
           | 
           | https://en.m.wikipedia.org/wiki/Fused_quartz
        
         | bjelkeman-again wrote:
         | Yes, the UV and heat will sterilise the water from bacterial or
         | viral contamination. If you have chemical contamination it will
         | not take that away.
         | 
         | https://akvopedia.org/wiki/UV_treatment_/_Solar_disinfection...
        
       | culi wrote:
       | key quotes imo:
       | 
       | > The powder consists of nano-size flakes of aluminum oxide,
       | molybdenum sulfide, copper, and iron oxide.
       | 
       | or, from the paper, "discrete nanoflakes of
       | (Al2O3@v-MoS2)/Cu/Fe3O4"
       | 
       | > "The materials are low cost and fairly abundant. The key
       | innovation is that, when immersed in water, they all function
       | together."
       | 
       | > The nontoxic powder is also recyclable. Iron oxide enables the
       | nanoflakes to be removed from water with an ordinary magnet.
       | 
       | > The chemical byproducts generated by sunlight also dissipate
       | quickly.
       | 
       | I'd be curious to learn more about potential byproducts. Seems
       | like the study focused on only a few types of wastewater. In
       | practice it'd have to handle a much larger variety of chemical
       | and biological constituents
        
       | aaron695 wrote:
       | [dead]
        
       | Animats wrote:
       | OK, so now what? FDA testing? Will this be in the backpacking
       | store soon? Bigger versions for home use?
        
         | alentred wrote:
         | So far this group only tested this solution on E.coli. This
         | sounds very encouraging, but many more studies are needed, I
         | would guess. So maybe not in the store tomorrow, but overall
         | quite promising.
        
       | BSEdlMMldESB wrote:
       | [flagged]
        
         | irdc wrote:
         | Bacteria have been warring on us since time immemorial. We've
         | only just noticed.
        
           | BSEdlMMldESB wrote:
           | [flagged]
        
       | pk-protect-ai wrote:
       | It seems that the water should be distilled, otherwise the
       | process will not be as predictable as it is described ...
        
       | bilsbie wrote:
       | Haven't iodine tablets been around for a long time? Why is this
       | better?
        
       | fnord77 wrote:
       | does overcast light work? I'm thinking of places where you don't
       | see actual sunlight for weeks at a time. Like the outer Richmond
        
       | eternityforest wrote:
       | Why can't we just blast the water with a lot of UVC, then add
       | some chlorine or something as we do now??? I don't want any
       | nanoparticles that could potentially leak past the magnet,
       | deposit in my skin, and make toxins if I go in the sun.
       | 
       | We could probably make a whole lot of UVC LEDS for cheap if we
       | scaled production. Plus, we already have lots of ways to filter.
       | Is this really gonna be that much cheaper? The world has plenty
       | of resources, seems like we could give people clean water with
       | current tech.
       | 
       | Can't titanium dioxide make hydrogen peroxide too? Why does it
       | have to be stirred in the water? Can't we have something bound to
       | a surface for the light to hit?
        
         | NotYourLawyer wrote:
         | If you're in a place without clean water, chances are pretty
         | good you're also in a place without electricity to run UVC
         | lamps.
        
           | eternityforest wrote:
           | But if you can bring in a nanoparticle based plant or
           | distribute the equipment you can probably bring in some solar
           | panels and batteries for a bit more cost, that probably would
           | be reasonable for whatever country or group is sending this
           | stuff, if someone really wanted to.
        
       | wen_1k_btc wrote:
       | No thanks, no aluminum in my drinking water.
       | 
       | Epidemiological studies suggest that aluminium may not be as
       | innocuous as was previously thought and that aluminium may
       | actively promote the onset and progression of Alzheimer's
       | disease. This condition is the most common form of dementia and
       | may contribute to 60 -70 % of cases. In 2015, dementia affected
       | 47 million people worldwide (or roughly 5% of the world's elderly
       | population), a figure predicted to increase to 75 million in 2030
       | and 132 million by 2050. Recent reviews estimate that each year
       | nearly 9.9 million people develop dementia globally; this figure
       | translates into one new case every three seconds (5). Even
       | prolonged exposure to low levels of aluminium leads to changes
       | associated with brain ageing and neurodegeneration (6).
       | 
       | Furthermore, aluminium has been included among 200 neurotoxic
       | chemicals that silently erode intelligence, disrupt behaviours,
       | truncate future achievements, and damage societies, perhaps most
       | seriously in developing countries. The latter is called the
       | "Silent Pandemic of Neurodevelopmental Toxicity in Children"
       | (7,8). Recently, the aluminium content of brain tissue in autism
       | spectrum disorder was found to be consistently high (9), and the
       | prevalence of autism spectrum disorder is increasing, last CDC
       | estimated prevalence is 1 in 44 children (10).
       | 
       | 5) World Health Organization. Global action plan on the public
       | health response to dementia. 2017-2025.
       | 
       | 6) Bondy SC. Prolonged exposure to low levels of aluminium leads
       | to changes associated with brain ageing and neurodegeneration.
       | Toxicology 315 (2014) 1-7.
       | 
       | 7) Grandjean P, Landrigan PJ. Developmental neurotoxicity of
       | industrial chemicals. Lancet. 2006 Dec 16;368(9553):2167-78.
       | 
       | 8) Grandjean P, Landrigan PJ. Neurobehavioural effects of
       | developmental toxicity. The Lancet Neurology, Volume 13, Issue 3,
       | Pages 330 - 338, March 2014.
       | 
       | 9) Mold M, et al. aluminium in brain tissue in autism. J Trace
       | Elem Med Biol. 2018.
       | 
       | 10) CDC. National Center on Birth Defects and Developmental
       | Disabilities, Centers for Disease Control and Prevention. Autism
       | and Developmental Disabilities Monitoring (ADDM) Network. 31
       | March 2022. Accessed 8 April 2022.
        
         | geraldhh wrote:
         | idk
         | 
         | "In the Earth's crust, aluminium is the most abundant metallic
         | element (8.23% by mass)"
         | 
         | https://en.wikipedia.org/wiki/Aluminium#Earth
        
           | ClumsyPilot wrote:
           | Alumium oxide only. It does not exist in pure form.
        
         | zafka wrote:
         | Adding pinch of potassium Permanganate is a good way to purify
         | water on a camping trip. Also carry a little glycerin with you.
         | Fun fire starting trick is to fill a bottle cap with
         | permanganate and pour a little glycerin on top - wait one
         | minute and presto: fire.
        
         | jaredhallen wrote:
         | If the alternative is giardia, I'll take the aluminum.
        
         | asdff wrote:
         | Your source 6 says we are all already drinking aluminum in the
         | drinking water so not much to be done.
        
           | dguest wrote:
           | I'm sort of confused: you could have said the same thing
           | about lead 70 years ago.
           | 
           | I guess your point is that we had better prove with absolute
           | certainty that this is a problem before we try to do
           | something about it, since it would be a bit expensive to
           | rework the entire world's plumbing and pointless to target
           | anything short of that.
        
             | jtbayly wrote:
             | I think the point is that this is just status quo. Drinking
             | water with aluminum is already the norm, so why refuse this
             | particular form?
        
         | MobiusHorizons wrote:
         | Note that it is Aluminum Oxide not elemental aluminum. Aluminum
         | Oxide is not very reactive, and completely insoluble in water.
         | if you were concerned about it, pass your treated water through
         | a coffee filter after removing the powder magnetically. I'd be
         | much more concerned about what this process can't remove from
         | water though, things like heavy metals or other chemical
         | contaminants.
        
           | shirleyquirk wrote:
           | Metallic aluminium is insanely reactive and any Aluminium
           | exposure will always be in the form of oxides or hydroxides.
           | It's disingenuous to suggest that it is inert in this form,
           | especially given that the point of the exercise is active,
           | complex, catalysed photochemistry.
        
             | syntaxing wrote:
             | Not a chemist but a MechE. How is aluminum insanely
             | reactive? Aluminum oxide is significantly less prevalent
             | than iron oxide (aka rust). Even on a sheet metal part, you
             | might get a couple microns worth of aluminum oxide. Hell,
             | we purposely anodize it so we get more aluminum oxide.
        
               | sclarisse wrote:
               | You anodize it to get more because the raw material is so
               | reactive that it forms a thin layer of oxide more or less
               | instantly. That keeps more oxygen out, but it's too thin
               | and can be easily scratched.
        
               | BostonEnginerd wrote:
               | Aluminum _is_ extremely reactive. It self-passivates with
               | Aluminum oxide very quickly. The difference between rust
               | and AlO3 is that the AlO3 adheres well to the base metal
               | and doesn 't flake off like rust does.
        
           | prox wrote:
           | Is aluminum magnetic? Didn't think so?
        
             | dspillett wrote:
             | No, that is why it might still there to remove with a
             | coffee filter, _after removing the powder magnetically_ , I
             | assume.
        
             | MobiusHorizons wrote:
             | > The powder consists of nano-size flakes of aluminum
             | oxide, molybdenum sulfide, copper, and iron oxide
             | 
             | Aluminum oxide is not magnetic, but the iron oxide
             | (presumably bonded to the other ingredients) is magnetic.
        
               | culi wrote:
               | The original paper specifies in the abstraction:
               | 
               | > discrete nanoflakes of (Al2O3@v-MoS2)/Cu/Fe3O4
               | 
               | https://www.nature.com/articles/s44221-023-00079-4
        
         | throwaway2990 wrote:
         | Yet you probably use toothpaste containing sodium fluoride or
         | drink tap water with sodium fluoride and think nothing of it.
         | That's probably worse for you. That's why a lot of places
         | stopped adding fluoride from drinking water and why you spit
         | tooth paste out and don't give children fluoride tooth paste
         | until they learn to spit.
         | 
         | While calcium fluoride is safe when consumed.
        
         | tiku wrote:
         | The aluminum is bound with the iron and other elements, so that
         | the magnet can retrieve it all from the water?
        
           | shirleyquirk wrote:
           | Not any kind of chemist, but I'm seeing molybdenum disulfide
           | plus (metal) coated on alumina support used as a catalyst, as
           | well as magnetic Al/Fe composite nanoparticles used for same.
           | Usually the metal is something more punk rock, like platinum,
           | cobalt, or ruthenium, but copper is an obvious choice on the
           | poisonous/cheap axis
        
           | adrianmonk wrote:
           | And this can be tested. Do a huge number of cycles of water
           | treatment. Maybe 1000 or something.
           | 
           | Measure the amount of aluminum in the powder before and
           | after. And/or measure the amount of aluminum added to the
           | water too.
           | 
           | You're going to have to do some testing similar to this
           | anyway since you need to know how long the stuff stays
           | effective. At some point it could wear out and lose its germ-
           | killing powers. Or maybe it doesn't, but you need to know
           | that.
        
         | hanwenn wrote:
         | According to the Alzheimer society, "Current research provides
         | no convincing evidence that exposure to trace elements of
         | aluminum is connected to the development of dementia." [1]
         | 
         | Because Aluminium is extremely common in the earth, it's also
         | impossible to avoid ingesting it.
         | 
         | Further info at [1]: https://alzheimer.ca/en/about-
         | dementia/how-can-i-prevent-dem...
        
           | culi wrote:
           | I'm not arguing for or against this, but I'd be really
           | hesitant to quote any organization that has large ties to the
           | Alzeimers research industry which is famously hostile to any
           | research that doesn't subscribe to the amyloid hypothesis. I
           | wouldn't be surprised if the argument against certain
           | contributing factors, like heavy aluminum exposure, were
           | based on lack of connection to amyloid plaque. STAT News did
           | a wonderful write-up on the tragic state of Alzeimer's
           | research back in 2019
           | 
           | https://www.statnews.com/2019/06/25/alzheimers-cabal-
           | thwarte...
           | 
           | > The scientists described the frustrating, even career-
           | ending, obstacles that they confronted in pursuing their
           | research. A top journal told one that it would not publish
           | her paper because others hadn't. Another got whispered advice
           | to at least pretend that the research for which she was
           | seeking funding was related to the leading idea -- that a
           | protein fragment called beta-amyloid accumulates in the
           | brain, creating neuron-killing clumps that are both the cause
           | of Alzheimer's and the key to treating it. Others could not
           | get speaking slots at important meetings, a key showcase for
           | research results. Several who tried to start companies to
           | develop Alzheimer's cures were told again and again by
           | venture capital firms and major biopharma companies that they
           | would back only an amyloid approach.
           | 
           | > "I don't think there was a purposeful attempt to scuttle
           | other approaches," Selkoe added. Or as Aisen put it last week
           | on the sidelines of the Aspen Ideas Festival, "I don't think
           | I'm part of a cabal."
           | 
           | > It isn't hard to understand why hundreds of academics lined
           | up behind the amyloid model over the years, Fitzpatrick said.
           | "Once a field commits to a particular hypothesis, the
           | research resources -- funding, experimental models, and
           | training -- all get in line," she wrote in a 2018 analysis.
           | That brings backers of the dominant idea accolades, awards,
           | lucrative consulting deals, and well-paid academic
           | appointments. Admitting doubt, let alone error, would be not
           | only be a blow to the ego but also a threat to livelihood.
        
           | tinglymintyfrsh wrote:
           | And rice produced in North America tends to concentrate
           | arsenic.
           | 
           | Because something is difficult doesn't mean it's okay to
           | rationalize more of it. Marketing something as "nontoxic" has
           | a storied history of failure. DDT for one.
           | 
           | Cost/benefit analysis always. Perhaps in a survival or
           | humanitarian crisis situation the risks of water-borne
           | diseases would be far greater.
        
           | tboyd47 wrote:
           | Then maybe it's not aluminum which is the problem, but some
           | natural detoxification process in the body which is being
           | inhibited.
        
       | human_person wrote:
       | This seems like an effective way to kill microbes without using
       | chemicals that could be harmful to humans. And the reusability
       | aspect is great. But does anyone know if the hydroxyl
       | radicals/hydrogen peroxide used to destroy the cell membranes
       | would have an impact on the shiga toxin? Also it sounds like it
       | takes up to 30 min to kill all viruses at 3% H2O2.
        
       | hammock wrote:
       | Molybdenum and copper are harmless??
        
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