Instant water cleaning method ‘millions of times’ better: study • Hacker News Board

Re: Instant water cleaning method ‘millions of times’ better: study

#111

Post by Cthulhu_ » Wed, Jul 07, 2021, 7:17 AM UTC

55555 wrote: post #92

wolverine876 wrote: post #90

Earlier quoted context omitted.

Thanks for the insights, though let's remember that research is just a first step. This isn't a product being announced for the market. If we looked at the original research behind a lot of mature technology, we'd find the state of the technology to be similarly far from from production. Now others can try to reproduce it, refine it, find other methods of producing the same reactive oxygen species, find substitutes t…

> This isn't a product being announced for the market. The press release makes bold implications tbh

They always do; it's a marketing statement.

Re: Instant water cleaning method ‘millions of times’ better: study

#112

Post by sschueller » Wed, Jul 07, 2021, 7:25 AM UTC

Funny, there was a report on Swiss TV[1] just yesterday where they were talking about how concentrating water cleaning systems is more effective. The went from 11 to 2 large water cleaning facilities in the Kanton of Uri as it is a lot easier to keep those using the latest standard than to maintain 11 separate facilities. They now pump the dirty water at hight pressure to the 2 facilities because of the large altitude drop the the pressure needs to be reduced so electricity is also generated from the waste water. The pipeline last around 70 years while a cleaning facility needs an overhaul every 25 years.

[1] https://www.srf.ch/play/tv/sendung/schweiz-aktuell?id=cb28dd...

Re: Instant water cleaning method ‘millions of times’ better: study

#113

Post by rocqua » Wed, Jul 07, 2021, 8:09 AM UTC

grenoire wrote: post #2

It seems that for both desalination and sanitation (as discussed in the article) of water is now an energy issue. What are some other basic problems (food, water, temperature management, etc.) we're facing that are primarily energy-bottlenecked?

I feel that, once you have reduced the consumables of something to energy, that doesn't tend to make it energy limited. Instead, it becomes capital limited. You need to be able to pay for the upfront capital costs of installing the thing.

Add to that the fact that, once these developments have happened, they tend to improve a lot, quickly. That means anything you build will, soon, be outdated and stop producing as much yield. Hence, you don't want to invest too much.

Re: Instant water cleaning method ‘millions of times’ better: study

#114

Post by krige » Wed, Jul 07, 2021, 8:27 AM UTC

gentleman11 wrote: post #19

gundmc wrote: post #8

How much gold and palladium are required? Those are massively expensive catalysts and it feels borderline disingenuous to talk about how this will bring clean drinking water to the masses without so much as mentioning cost.

> The catalyst-based method was shown to be 10,000,000 times more potent at killing the bacteria than an equivalent amount of the industrial hydrogen peroxide Even if it required a fair bit, 10M is a really big number. Long term savings would be huge since the catalysts aren’t consumed in the reactions

The "equivalent amount" of H2O2 is actually a really pathetic amount (0,01%) and potency is not linear with concentration. Actual concentration of H2O2 that's used for these purposes is only 60 times higher (0,6%) and achieves similar 10^8 times better results as 0,01%.

Plus they only tested vs E. Coli which is not very durable as far as nasty microbes in your water go.

Re: Instant water cleaning method ‘millions of times’ better: study

#115

Post by elihu » Wed, Jul 07, 2021, 8:31 AM UTC

> The team showed that as the catalyst brought the hydrogen and oxygen together to form hydrogen peroxide, it simultaneously produced a number of highly reactive compounds, known as reactive oxygen species (ROS), which the team demonstrated were responsible for the antibacterial and antiviral effect, and not the hydrogen peroxide itself.

Interesting. I hope those aren't harmful to humans (or plants, or other animals). Also, from the high reactivity I suppose they might not stick around very long, which could be a good thing or a bad thing depending. It might be useful to be able to treat a large amount of water without leaving any long-lasting impurities, but on the other hand you might have to treat the water again if you want to store it any length of time... On the other hand, if a reactive thing doesn't have anything to react with, maybe it does persist for a long while?

Re: Instant water cleaning method ‘millions of times’ better: study

#116

Post by KSteffensen » Wed, Jul 07, 2021, 9:16 AM UTC

yxhuvud wrote: post #104

jcranmer wrote: post #83

Oh dear. After reading the notes in the study itself about the scale this was done at, scaling up might be an issue: > A typical H₂O₂ synthesis reaction was carried out using 120 mg of 1% AuPd/TiO₂ [...] The reactor system was then pressurized, typically to 10 bar. The reactor was then cooled by a water bath to 2 °C. When the reactor had reached the required pressure and the flow through the system had stabilized, th…

I wonder if it could replace clorinated water in swimming pools though.

This can already be done using UV light possibly combined with ozone treatment.

I'm not sure what the hydrogen peroxide method brings to the table compared with UV/ozone (besides a university press release).

[0]: https://www.espwaterproducts.com/ultraviolet-uv-systems/

[1]: https://www.socotec.co.uk/media/faqs/faqs-ozone-water-treatm...

Re: Instant water cleaning method ‘millions of times’ better: study

#117

Post by rightbyte » Wed, Jul 07, 2021, 9:16 AM UTC

elif wrote: post #95

wouldn't 1,000,000x improvement in bacteria killing be actually lethal to gut flora?

I mean, just spit in the water if that is a problem.

Re: Instant water cleaning method ‘millions of times’ better: study

#118

Post by yesenadam » Wed, Jul 07, 2021, 9:47 AM UTC

azalemeth wrote: post #106

jcranmer wrote: post #83

Oh dear. After reading the notes in the study itself about the scale this was done at, scaling up might be an issue: > A typical H₂O₂ synthesis reaction was carried out using 120 mg of 1% AuPd/TiO₂ [...] The reactor system was then pressurized, typically to 10 bar. The reactor was then cooled by a water bath to 2 °C. When the reactor had reached the required pressure and the flow through the system had stabilized, th…

What does MGD mean, and what is it in SI units? Million gallons per day? US gal or Imperial ones? (I'm not being facetious -- I genuinely don't know and it's my understanding that the US mix parts of the old British Imperial system, e.g. BTU, together with their own)

A minute's googling revealed that, yes, it's million gallons/day, and it seems both Imperial and US gallons are commonly used, so depends on author's nationality which is meant, I suppose.

Re: Instant water cleaning method ‘millions of times’ better: study

#119

Post by honie » Wed, Jul 07, 2021, 10:09 AM UTC

neltnerb wrote: post #108

honie wrote: post #102

Earlier quoted context omitted.

> Seriously though, couldn't they just use far less catalyst and not have to deal with the prices you've calculated? The flow rate is likely positively correlated with catalyst loading (in the part that we care about) and the calculation is already based on the flow rate of 0.2 ml min¯¹ they reported in the paper. The reported flow rate is also likely already optimised for the Nature Communications paper.

It is very unlikely that they could have even explored the full parameter space if they wanted to, it's such a huge undertaking. It's probably optimized under some constraints, but there's a huge number of things involved -- support material, surface area, catalyst metal, alloying, promoters, pretreatment, temperature, pressure, flow rate -- my experience has been that you can take any catalyst and make it work a lot…

> It is very unlikely that they could have even explored the full parameter space if they wanted to, it's such a huge undertaking...

Absolutely agree and no arguments whatsoever. In fact, one of the first things that I joked to myself was that we will soon see papers on MOF-suppoorted version of the catalyst -- well before we see any DoE.

In any case, I just want to note that I made the comment in response to the following:

> $190 million -> 190 bucks ;)

Which appears to be a misunderstanding, as the calculation in question has implicitly taken into account the "millions of times" increase in disinfection efficacy.

> I think it'd be a bigger deal if it didn't require pressurization to 10 bar personally, pumps are expensive to operate and catalysts are a one-time-cost (if you're lucky).

I felt uncomfortable about the pressure, too, but it was just a hunch. Thank you for putting this into context. :)

Edit: clarity, typo.

Re: Instant water cleaning method ‘millions of times’ better: study

#120

Post by nico_h » Wed, Jul 07, 2021, 10:19 AM UTC

wolverine876 wrote: post #90

jcranmer wrote: post #83

Oh dear. After reading the notes in the study itself about the scale this was done at, scaling up might be an issue: > A typical H₂O₂ synthesis reaction was carried out using 120 mg of 1% AuPd/TiO₂ [...] The reactor system was then pressurized, typically to 10 bar. The reactor was then cooled by a water bath to 2 °C. When the reactor had reached the required pressure and the flow through the system had stabilized, th…

Thanks for the insights, though let's remember that research is just a first step. This isn't a product being announced for the market. If we looked at the original research behind a lot of mature technology, we'd find the state of the technology to be similarly far from from production. Now others can try to reproduce it, refine it, find other methods of producing the same reactive oxygen species, find substitutes t…

Maybe they can use metallic foam to increase the surface area of the catalyst and increase the flow rate without scaling the noble metal usage at the same rate as the flow!