Water filtration is indeed a key survival technology for humanity in the next 50-100 years, so seeing technology already providing possible solutions to the so-called "water wars" of the future is great!
I presume such a filter will also remove all bacteria/etc from the water. So basically, you could grab some water from the Thames, stick it through one of those filters, and drink it. It might lack some minerals, but it won't get you sick.
From the article, they are talking about filtering evaporated water through the membrane. It sounds like you will be waiting a long, long time for that drink of water filtered via its gaseous phase through this material.
Regarding bacterial contamination concerns that the posters below discussed, they are likely remedied if the filtration occurs in the gaseous phase of water, though some bacteria can climb substrate walls against gravity so it would be an interesting engineering design challenge.
But getting water into the gaseous state is quite easy, by adding heat, right? I realize that takes (quite a lot of) energy, but if all of the water that is heated past vaporization becomes 100% cleaned with no other energy input and no moving parts, that sounds like a rather nifty machine.
I'm sure there are engineering constraints that I'm not aware of, like the filtering clogging up and so on, of course. Still, it sounds almost magical with such a perfect filter.
The watercone is great for non-potable water that isn't contaminated with compounds that also boil below or near 100 °C and are either in A) high proportion or B) that bio-accumulate.
If the preliminary findings with the graphene oxide are hold true, you could stick a cap made of the stuff on a watercone evaporating a bunch of zombie blood and end up with ASTM Type I water to keep you hydrated after the zombie apocalypse.
In order for this statement to be relevant I think you must be of the opinion that zombie blood contains compounds that boil below or near 100°C. Otherwise you still wouldn't need graphene oxide cap.
So I'm wondering if zombie blood is known to have these type of compounds. But more importantly, how common is it for typically impotable water to have these type of compounds?
Ignoring the zombie blood for a second (because you're absolutely correct) I'll approach your last question.
> how common is it for typically impotable water to have these type of compounds?
My gut feeling is, "not very... right now." The "right now" is pretty much the problem with the speculated water wars (though a bunch of the water in the Gulf of Mexico does contain those compounds).
With landfill's "impermeable" barriers becoming permeated and cholesterol medications, caffeine, birth control, and various other drugs remaining in the treated effluent from waste water facilities coupled with humanity's generally reckless disregard for consequences to its actions there's a significantly non-zero chance that fresh, clean potable water will become scarce in multiple developed locations worldwide.
On the other hand, it could very well be that as our understanding of bio-remediation increases and our utilization of passive and active purification techniques and/or technologies increases we'll keep from having that be a problem. Potentially, we'll even stop actively polluting our water supplies with industrial, agricultural and residential wastes to "save a buck."
Anyway, the watercone is great. They've tackled usability issues present in other solar distillation devices and for areas with access to water with high salinity, or biologically contaminated water (though, there is risk of cross-contamination when harvesting your purified water). It's just that solar stills aren't always a replacement for filters.
You're right, which would explain why they experimented with vodka. It seems this filter is better at filtering water out of a substance, rather then filtering substances out of water.
Well, that presumes a perfect seal on the filter, because otherwise the bacteria can just take the long way around the filter and into your filtered water.
That's not a show-stopper, though, is it? I mean, you could get near-perfect just by making the filter the right shape and having several layers of filtering, thus reducing the chance of a bacteria getting through down to some infinitesimal probability...
I presume such a filter will also remove all bacteria/etc from the water. So basically, you could grab some water from the Thames, stick it through one of those filters, and drink it. It might lack some minerals, but it won't get you sick.