I got an opinion on the story on the link I am replying to from and oil engineer. He knows more about "What is in the ground" than anybody I know. Here it is>>>
from OakesCS
I wouldn't hold my breath for graphene becoming a cheap means of converting seawater to potable water. Cheaper means already exist. Graphene has apparently become a scientific and commercial fad where funding has become easily available so any yahoo can dabble in their own niche topical area. I know a bunch of guys who set up a graphene focused company and none of them know anything about chemistry but apparently some VC funders were swayed.
just in case it matters: in the case you posted, graphene/graphite-oxide sheets are stacked with the plane of the sheets parallel to the direction of flow (if i knew how to paste images, this would be clearer). The distance between the stacks is just large enough to pass water molecules while electrical repulsion effects between solute ions an localized charges at the channel entrances preclude passage of the solute ions thru the channels (the authors appear to claim that it's an ion hydration sphere size effect but that's bunk cuz the hydrating H2O molecules are not statically associated with individual ions). This ends up making the water on one side of the graphene 'filter' very salty while the other side is nearly pure water. As a consequence of that situation there is a progressively greater osmotic gradient which opposes the mechanical pressure applied to force water thru the 'filter'. Reverse osmosis water purifiers have the same problem which can obviously be dealt with but if osmotic water purification systems can do the same job for lower cost, why bother with graphene?
For a good chunk of the world, the biggest problem with water is not lack of quantity or dissolved salts but the nasty biologics in or associated with the available water. Of course, if those problems are slain the cure begets additional problems.
In the US there is simply enormous waste. If more people in the US (I'd focus on California) had to occasionally carry their daily useage from a well or spring i suspect there would be a lot less waste and fewer stupid regulations. A few less golf courses in places where there shouldnt be golf courses wouldnt be missed.
from OakesCS
I wouldn't hold my breath for graphene becoming a cheap means of converting seawater to potable water. Cheaper means already exist. Graphene has apparently become a scientific and commercial fad where funding has become easily available so any yahoo can dabble in their own niche topical area. I know a bunch of guys who set up a graphene focused company and none of them know anything about chemistry but apparently some VC funders were swayed.
just in case it matters: in the case you posted, graphene/graphite-oxide sheets are stacked with the plane of the sheets parallel to the direction of flow (if i knew how to paste images, this would be clearer). The distance between the stacks is just large enough to pass water molecules while electrical repulsion effects between solute ions an localized charges at the channel entrances preclude passage of the solute ions thru the channels (the authors appear to claim that it's an ion hydration sphere size effect but that's bunk cuz the hydrating H2O molecules are not statically associated with individual ions). This ends up making the water on one side of the graphene 'filter' very salty while the other side is nearly pure water. As a consequence of that situation there is a progressively greater osmotic gradient which opposes the mechanical pressure applied to force water thru the 'filter'. Reverse osmosis water purifiers have the same problem which can obviously be dealt with but if osmotic water purification systems can do the same job for lower cost, why bother with graphene?
For a good chunk of the world, the biggest problem with water is not lack of quantity or dissolved salts but the nasty biologics in or associated with the available water. Of course, if those problems are slain the cure begets additional problems.
In the US there is simply enormous waste. If more people in the US (I'd focus on California) had to occasionally carry their daily useage from a well or spring i suspect there would be a lot less waste and fewer stupid regulations. A few less golf courses in places where there shouldnt be golf courses wouldnt be missed.
