Sunlight-activated material turns PFAS in water into harmless fluoride | Hacker News Reader

Sunlight-activated material turns PFAS in water into harmless fluoride

phys.org

79 pointsbookofjoe30 comments

The Materials Science Gameplay Loop:

1. Invent fantastic new material that does a heretofore novel reaction or one with improved performance (chemical, photovoltaic, etc.)

2. Do #1 without lead, cadmium, mercury, or arsenic.

SociallyAwesomeAwkwardPenguinMeme("Turns PFAS to fluoride", "Contains Cadmium")

Alternative path, like with General Electric:

Invent seemingly fantastic new material. Discover it is harmful to humans and wildlife, accumulates in groundwater, etc. Bury that discovery.

Get caught after decades of wild profits, the occasional secret settlement, and spend a decade more fighting legal action before finally running out of appeals or the writing is on the wall, and accept it and pay out.

Start selling water filtration systems, thus profiting off people dealing with your pollution.

This is what I find so frustrating about "the fight against cancer." I'm convinced cancer is so prevalent because corporations are poisoning the shit out of our environment, and thus our water supply, our food, our air. Because we're not equipped with timestamping chemical detection systems, it's difficult to identify the exposure that caused it or increased the person's risk, so industry gets a "freebie" death nobody can pin to them. As long as the chemical isn't toxic enough to be obvious - the companies get away scott free, despite an extensive history of the chemical industry time and time again coming up with some major novel chemical that comes to be used all over society and turns out to be toxic.

Bill Moyers once submitted his blood to a lab and asked them to test for everything they could identify in terms of industrial chemicals, pesticides, etc. The blood was a veritable toxic soup (and some of the control sample containers were contaminated from the supplier, showing how pervasive the toxins are): https://www.pbs.org/tradesecrets/problem/popup_bb_02.html

You don't "fight cancer" doing walks and charity balls and cute-kid-starts-fundraiser-because-friend-dies-from-leukemia. You fight cancer by addressing the toxins being pumped into us in the name of profit and "bettering society", allowed to get away with it because of how difficult it is to show any particular chemical directly caused the cancer.

It's a bit disheartening to see that the Bill Moyer's documentary came out in 2001, and not much has changed to keep these corporations accountable.

If only the vaccine-autism energy could be directed in the right place

PS not to diminish GE's game but they certainly weren't the only player. This one always stuck with me: https://en.wikipedia.org/wiki/Minamata_disease#Wastewater_tr...

Sadly the goal of vaccine-autism energy has largely become to destabilize western nation states. But I share the sentiment!

Growth and consumption under all circumstances. And we’re fuelling it with our personal behavior.

3. Do #2 without platinum, palladium, rhodium, ruthenium to make it economically viable

Is that much of a problem for a catalyst? Presumably you do not need many of these: at water treatment plants and at the waste-stream for manufacturing processes which emit PFAS. You might not be able to justify the expense inside your home water purification system, but it could still be cost effective for large scale installations.

You would need a lot of catalyst because the water infrastructure to supply several hundred million people in the US is massive, let alone the rest of the world.

The problem with those catalysts is that the latter two are minor components of platinum and copper/nickel ores and despite how expensive they are, the extraction is only economically viable as part of other mining. Their supply can only grow as much as platinum extraction allows and demand is already pretty significant with environmental regulations often necessitating their use. Any more demand for them will cause their prices to rise dramatically and its a long way before they become profitable enough to mine on their own (flooding the platinum market in the process which has much higher yields from the ores).

it depends on the scale and the required amounts. If having a limited amount of catalyst wasn't such a big problem I suspect hydrogen power would have been much more economically viable.

I thought the point of catalysts was that they don't get used up in the reaction they promote.

The real world is messy - catalysts gradually need replacement over time in non lab conditions

https://en.m.wikipedia.org/wiki/Catalyst_poisoning

The issue with hydrogen is the source of hydrogen.

Activated carbon filtering removes up to about 75% of PFAS. Reverse-osmosis removes almost all.

Doesn't get rid of them, to be clear. It would still be better if a way could be found to chemically (and cheaply) convert them to something less harmful.

> Activated carbon filtering removes up to about 75% of PFAS

Common inexpensive non-RO filter systems come with independent test results showing 99% removal of PFOA/PFOS (see e.g https://www.brondell.com/content/UC300_Coral_PDS.pdf). Do we have reason to believe that other PFAS don't filter as easily?

AIHI the shorter PFAS molecules are not captured as effectively by activated carbon.

> Activated carbon filtering removes up to about 75%

Seems like the limitation must be more than reducing concentrations in fluid? Otherwise you'd just do multiple passes?

Yes, the key here is the degradation of the forever chemical, not the removal. Removal itself doesn't really change the environmental scale of it

Ignoring the cadmium problem, is fluoride really harmless? I don't know what concentration of fluoride you'd end up with from converting typical PFAS pollution, but if you get enough fluoride it is acutely poisonous, which might be worse than the carcinogenic PFAS. (Likewise, it might be worse for the environment)

Fluoride doesn't bio-accumulate like PFAS do, which has a strong affinity for proteins and fats in organisms. Constantly drinking water with 0.5-1 ppm fluoride may cause minor side effects like mild dental fluorosis, but you'll excrete almost all the excess as it's very water soluble. Drink water with any PFAS, and your body will strongly hold on to it all.

"0.5-1 ppm" covers what's considered the optimum level of fluoride in drinking water, so I doubt you'd get dental fluorosis from that. Coincidentally, if you calculate the equivalent dose that you'd give babies (via dissolved vitamin D + fluoride tablets), you also end up at about 0.3-0.5ppm.

Everything is toxic at a certain conentration, but as far as i know PFAS is a million times more toxic than flouride.

According to the EPA safe level for flouride for drinking water is up to 4 mg/L. The epa level for PFOS is 0.000004 mg/L, literally a million times lower.

I thought the EPA was deregulating everything except flouride which it was going to deem a poison.

Fair point. We should probably have some way to refer to US gov’t funded scientific orgs & their research/recommendations before vs after the 2nd Trump Administration.

Pre/post 47.

Fluoride?!!

Isn't that supposed to be some kind of demonic juice?

Why else is the government so intent on making sure that there's none in our water? I'm sure that they would much rather have the PFAS, produced by their nice, generous, industrialist bros.

And PFAS are used heavily in the manufacturing of microchips (photoresist and etching).

The PFAS are the mellowest chemicals they use.

I think they use this stuff: https://www.science.org/content/blog-post/sand-won-t-save-yo...

At least that will self-decompose, reactive chemicals aren't usually a problem

I'm a bit confused, are they suggesting that a cadnium coumpound to treat PFAS is a done deal?

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