Scientists discover cheap material that can remove mercury from water | Hacker News Reader

Scientists discover cheap material that can remove mercury from water

thenewdaily.com.au

81 pointsantineutrino11 comments

The full paper is at http://onlinelibrary.wiley.com/doi/10.1002/anie.201508708/fu... and titled 'Sulfur-Limonene Polysulfide: A Material Synthesized Entirely from Industrial By-Products and Its Use in Removing Toxic Metals from Water and Soil'.

> In conclusion, we have explored the properties of a polysulfide synthesized entirely from the industrial by-products sulfur and limonene. The polysulfide is easy to synthesize on a large scale and requires no exogenous reagents or solvents. The polysulfide removes PdII and HgII from water and soil and turns yellow when exposed to mercury(II). This response is selective for mercury, a discovery that may find use in sensing applications. We plan to develop the sulfur-limonene polysulfide as an inexpensive material for environmental remediation, where it will be used to sequester toxic metals from complex mixtures. More generally, this research is part of a growing effort to identify new and useful properties of materials with high sulfur content6 and to synthesize them in an efficient and sustainable fashion.

If they can come up with a variant on this that is specific to arsenic, the implications for Pakistan are huge.

http://www.dawn.com/news/356241/lahore-high-arsenic-concentr...

If you can come up with ANY variants that remove ANY other heavy metals the implications for EVERYWHERE are huge.

Bangladesh more so

Huh, sulpher-containing food (garlic, onion, cabbage, etc) has long been recommended to aid in the flushing of heavy metals as it's believed that they aggressively bind together to make much more bio-mobile compounds.

While mention of that possibility appears in the literature, the only tests I can find are on animals, and they don't seem all that conclusive to me.

To be a useful recommendation, I would like to know the dose. That is, if the water has a 50% higher lead concentration, how much garlic (etc.) should I eat to mitigate the possible ill effects? Is a clove/week enough? 20 bulbs/day?

For example, if I go by http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4279617/ which tests "A. sativum extract (400 mg kg-1 ..." on rodents, then that's equivalent to someone weighing 100 kg eating 40 g of garlic. A clove is about 3 grams, so 40 grams is a bit over a head of garlic per day. Which is rather a lot.

I would think the garlic (etc.) growers would be all over this, since if they could convince the millions of people living in areas with high lead concentrations to eat an extra head or two of garlic (etc.) per day, then that's an economic boom for them.

I would also worry that it depends on the kind of food. Does it exclude Vidalia onions? What other onions should we avoid? How should they be labeled?

I also can't help but think of scurvy treatments. The British Navy first used limes. Quoting from https://en.wikipedia.org/wiki/Scurvy :

> West Indian limes replaced lemons because they were more easily obtained from Britain's Caribbean colonies[18] and were believed to be more effective because they were more acidic, and it was the acid, not the (then-unknown) Vitamin C that was believed to cure scurvy. In fact, the West Indian limes were significantly lower in Vitamin C than the previous lemons and further were not served fresh but rather as lime juice, which had been exposed to light and air and piped through copper tubing, all of which significantly reduced the Vitamin C.

That is, is it really the high sulfur in garlic (etc.) which helps, or is it something else?

I tried to find this information, but was overwhelmed by people saying they are traditional medicine, with pointers to others who then point to etc. I didn't find anything like a dose/response curve, even for rodents.

Well, the sulfur-limonene polysulfide compound worked on mercury (Hg) and palladium (Pd). So if you want to use it to remove lead (Pb), you might have to add dyslexide as a side-group to the polymer.~

EDTA will chelate almost any positively charged metal ion in the body, including arsenic and lead, but will also grab stuff like iron, zinc, calcium, and magnesium, which are rather important to keep. EDTA has two amine ligands and four carboxylic acid ligands. But the metals you really want to get rid of--like lead, mercury, cadmium, and arsenic--are attracted to amine, thiolate, and sulfhydryl groups.

So peptides containing multiple cysteine groups are often used in biology to bind and transport toxic heavy metals. Methionine, as another sulfur-containing amino acid, is also useful. So N-acetylcysteine and S-adenosylmethionine help clear heavy metals from the body without also sucking out the metals you would prefer to keep. If you can come up with a better, more selective chelation agent, you're likely to get a few prestigious prizes.

I don't think eating enormous quantities of garlic is likely to be a great solution. I'd probably just go with a N-acetylcysteine supplement--which also has the beneficial side effect of helping with hangovers--and use lead testing strips (if red, there's lead) to avoid chronic exposure. Also, no allium-halitosis.

Vidalia onions are mild and sweet because they are grown in low-sulfur soil. Tangy, pungent onions are the ones that will have higher levels of organosulfur compounds, so they're the ones you want if you're worried about heavy metals poisoning.

But then again, those organosulfur compounds can also help carry heavy metals into your body, so if the onions are grown in high-sulfur, high-arsenic soil, for instance, you're probably just making things worse.

I'm curious if this is common knowledge or not. A quick look at the wikipedia page for acetylcystine does not mention using it as a chelating agent, although it does seem to have a variety of other uses. Is this an oversight of the Wikipedia editors, or is this not a common recommendation?

It doesn't work very well by itself as a chelating agent. But it does have an amine group and a thiol group, and can form complexes with heavier metals. Having only two ligands, that aren't positioned very advantageously relative to each other, it just doesn't "stick" very well.

It's primary usefulness would be to replace the raw materials that the body uses to make the larger peptide molecules that it uses to detoxify heavy metals. Most of these require cysteine or glutathione, for the thiol.

I think NAC is mostly known to broscience as a hangover remedy, as it helps clear acetaldehyde in the liver.

I wonder if it's as simple as ensuring diet includes adequate & consistent sulpher intake optimizes glutathione? It's likely a lot more complicated than that though.

That's a useful result, I jokingly thought they were going to say Tuna since its been such a challenge in the Pacific. The next step I suppose would be to turn this stuff out in bulk and line drain pipes to see how well it works passively?

I didn't pick up if it was reversible, do you discard it after it has become saturated?

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