UK researchers create graphene-based sieve that can remove salt from seawater • Hacker News Board

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#11

Post by dijit » Mon, Apr 03, 2017, 10:59 PM UTC

ghaff wrote: post #4

dijit wrote: post #2

I hope this isn't Science being taken to a irrational extreme, as tends to happen with news and science. This has incredible potential not only for the developing world but also for sea travel and even the fact that we are running out of drinkable water in the west. Only 2.5% of the water on the planet is even potentially drinkable. If we were able to convert even 1%. Crazy.

Note that reverse osmosis desalination through membranes already exists as the article notes. (Not sure what the current state of the art is as I haven't worked in this area for a long time.) The question in whether this has advantages to the desalination systems used today.

My impression was that removing salt/saline from water is possible but it consumes a lot of energy to do so.

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#12

Post by johncolanduoni » Mon, Apr 03, 2017, 11:00 PM UTC

beatpanda wrote: post #7

M_Grey wrote: post #5

I swear I've heard about this before... is this one of those stories that emerges about a technology that never seems to enter the market? That "super slick" coating for condiment container interiors is another that springs to mind.

Yes, it is. My understanding is that there are still barriers to producing enough graphene at a large enough scale to make many of its uses commercially viable. http://www.azonano.com/article.aspx?ArticleID=3677

Production appears to be what they are improving here:

> But it has been difficult to produce large quantities of single-layer graphene using existing methods, such as chemical vapour deposition (CVD). Current production routes are also quite costly.

> On the other hand, said Dr Nair, "graphene oxide can be produced by simple oxidation in the lab".

> "In terms of scalability and the cost of the material, graphene oxide has a potential advantage over single-layered graphene."

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#13

Post by Keyframe » Mon, Apr 03, 2017, 11:09 PM UTC

M_Grey wrote: post #5

I swear I've heard about this before... is this one of those stories that emerges about a technology that never seems to enter the market? That "super slick" coating for condiment container interiors is another that springs to mind.

Graphene was re-discovered only in 2004. It takes time.

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#14

Post by johncolanduoni » Mon, Apr 03, 2017, 11:09 PM UTC

mgberlin wrote: post #10

tl;dr: A material was produced on a very small scale, which, with no regard to the energy required, might be able to remove 97% of the salinity. I.e. science-ey click-bait with a bullshit title.

Not really, their whole purpose was to find a way to produce suitable membranes with something much easier and cheaper to produce than traditional graphene sheets (i.e. graphene oxide). The article not only puts adequate focus on that issue, but even ends in a cautionary note about the future work required.

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#15

Post by jessriedel » Mon, Apr 03, 2017, 11:13 PM UTC

M_Grey wrote: post #5

I swear I've heard about this before... is this one of those stories that emerges about a technology that never seems to enter the market? That "super slick" coating for condiment container interiors is another that springs to mind.

Desalinization is already with about a factor of 2 or 3 of the thermodynamic optimum, so improvements can't be revolutionary. Desalinization mostly needs cheap clean energy.

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#16

Post by Alex3917 » Mon, Apr 03, 2017, 11:14 PM UTC

Keyframe wrote: post #13

M_Grey wrote: post #5

I swear I've heard about this before... is this one of those stories that emerges about a technology that never seems to enter the market? That "super slick" coating for condiment container interiors is another that springs to mind.

Graphene was re-discovered only in 2004. It takes time.

From the discovery of new basic science to commercialization usually takes 30 - 40 years. We're not even halfway there yet.

E.g. look at how long it took to develop digital cameras, flat screen TVs, etc.

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#17

Post by daveguy » Mon, Apr 03, 2017, 11:14 PM UTC

larsiusprime wrote: post #3

dijit wrote: post #2

I hope this isn't Science being taken to a irrational extreme, as tends to happen with news and science. This has incredible potential not only for the developing world but also for sea travel and even the fact that we are running out of drinkable water in the west. Only 2.5% of the water on the planet is even potentially drinkable. If we were able to convert even 1%. Crazy.

The question, as always, is how much energy it takes to do the filtering.

Yup. Sieve implies that the only energy required is that necessary to pump the water to a level above the filter. I highly doubt that is the case. Surely you need some significant pressure differential. Even with pores the size of proteins (100x+ larger) you need pressure.

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#18

Post by pthreads » Mon, Apr 03, 2017, 11:14 PM UTC

mgberlin wrote: post #10

tl;dr: A material was produced on a very small scale, which, with no regard to the energy required, might be able to remove 97% of the salinity. I.e. science-ey click-bait with a bullshit title.

Sorry, but that is a very misleading tl;dr.

I encourage other HN readers to actually read the article. I found it quite informative. Especially the use of graphene oxide instead of single-layer graphene.

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#19

Post by threeseed » Mon, Apr 03, 2017, 11:16 PM UTC

mgberlin wrote: post #10

tl;dr: A material was produced on a very small scale, which, with no regard to the energy required, might be able to remove 97% of the salinity. I.e. science-ey click-bait with a bullshit title.

1. This is the BBC. They aren't a clickbait site.

2. I count about 12 words you can fit into the title. How else can you adequately describe what the article was about ? Their choice seems completely reasonable.

3. The scale and energy required are irrelevant. The article wasn't describing a fully fledged product it was discussing a concept.

Re: UK researchers create graphene-based sieve that can remove salt from seawater

#20

Post by mmaunder » Mon, Apr 03, 2017, 11:18 PM UTC

Reverse osmosis has been around for a long time and is used on boats everywhere for desalination. This sounds like a new membrane that requires less pressure and thus energy? I guess sieve sounded better?