> The technology works by adding the compound diamine to saltwater. The type of diamine used is CO2-responsive, meaning that the substance’s behaviour can be controlled when it comes into contact with CO2. The diamine binds with the added CO2 and thereafter acts as a sponge to absorb the salt, which can then be separated. The entire process takes 1-10 minutes. Once the CO2 is removed, the salt is released again – allowing for the chemicals to be reused for several more rounds of desalination.
This article leaves a lot to be desired.
There is no compound called "diamine." Diamines are a class of compounds. Without knowing which one is being used, there's not much of a discussion to be had. We can say nothing about practicality or environmental impact, not to mention a host of other issues.
What may be happening here is the formation of a dicarboxamide, which then does something. That carboxamide formation is not likely to be reversible at room temperature.
The article has no link to the primary paper, where issues like this could readily be addressed, and there is absolutely no excuse to ever neglect to do so in 2020.
"Currently, the CowaTech technology is at technology readiness level (TRL) 2-3."
Which, for the uninitiated, means it is starting feasibility testing and are just barely starting development. I would bet they haven't solved that in any significant scale, that sort of issue wouldn't have come up yet at their development level.
Intuitively, I'm not a specialist, if water desalinization with there compound was more energy efficient than the current process, they would be on course to demonstrate it. They would not be working on "water bottles [...] for outdoor activities". Since they estimate a 50% efficiency gain would make it viable, it probably consumes about 125% energy compared to the current process.
Correcting my own mistake. If a 50% improvement is required to be more efficient than the current process, it means their process consumes up to twice, 200%, the energy.
Having worked on many R&D projects, I am nearly certain that any claims they make about efficiency are about as reliable as a startup telling early employees that their stock will be worth something. Sure, it could be true.
Frankly I doubt that they've done a detailed enough analysis to know these kinds of things at TRL 2-3, at best they've done a back of the envelope calculation based on lab results at small scale to show it's not obviously stupid, or if they're really on the ball they've got a license for Aspen and have some incredibly oversimplified model that shows it's not obviously stupid.
Really, at this development level, "not obviously stupid" is a pretty positive thing. If they're doing the work right, they are trying to demonstrate that it's stupid every day because that's how you avoid discovering it's stupid after five years of R&D and $50M.
Maybe you are in your area of expertise. I admit I am not.
In computer science, such efficiency gains are rather common. In physics, and thermodynamics in particular, a single 5% energy efficiency gain is huge.
Yes, this is very close to my area of expertise, my previous job title was director of chemical process development but I've got my degrees in materials science and physics so I think I mostly understand what they're doing in a broad sense if not the details at small scale. But yes, a 5% energy efficiency gain would be an enormous deal for some chemicals like ammonia. A 1% efficiency gain there is last I checked 2 power plants per year that could be taken offline in response to the lost demand.
But for most chemicals the energy efficiency is important while material efficiency is more important. Usually there are tradeoffs. For instance I have made a chemical to 99.8% purity without a ton of purification. If it were to 99% then I'd have to spend a lot more energy to reach 99.8% purity (which happened to be required to be useful as a product). But the process to reach 99% is simpler and uses less energy than the process to reach 99.8%. So really it's just an optimization problem where you definitely cannot assume that improving the yield or efficiency of one part of the system will result in an overall efficiency improvement unless you model it all.
The problem is that it is premature to talk about energy efficiency in any remotely meaningful way here because the "big box" you need to draw around your system is vastly bigger when you're talking about a complicated plant doing by my count at least a dozen (including heating, cooling, separations, etc) processes simultaneously.
I'm not saying that their idea wouldn't work in that context, I am simply saying that at TRL 2-3, if this were me doing the work, we would have noted the amine issue and deferred it until a later TRL level because it's theoretically a non-core technology to remove it. It doesn't tell you much about your throughput of your membrane or what salt gradients it works with or how to power it -- that's what I would expect them to be focusing on.
Removing the amine would be like TRL 3-4 maybe, if they're on the ball, but they have to attack the problems most likely to result in failure first. Amine contamination is way lower on a priority list than, say, the membrane rupturing every seventeen days. That's literally just more where I would guess they are at development-wise, regardless of whatever claims they make.
I just cannot trust claims made at that TRL level, at best they're extremely optimistic guesses extrapolated from a 1L benchtop apparatus they are trying to model a whole plant using data from. It's a good thing to do. It won't give a correct answer, but it will give you an idea of what's important at least.
I was unable to find the source. I searched the name "Ji-Woong Lee" of University of Copenhagen, I found his bibliography [0] and Twitter account [1], but I was unable to find any paper on CO2-enabled saltwater desalination. The only CO2-related paper was about its applications in organic synthesis, "CO2-Enabled Cyanohydrin Synthesis and Facile Homologation Reactions" [2].
But he did repost a press release on Twitter. Perhaps the paper is not published yet?
Yes. This is the source, I've seen the English version too [0]. But it's not the actual research paper (I should have said "paper", not "source"). The press release is too vague for any technical detail.
I tried to find a paper too, but couldn't find anything. I did find a little more information on CowaTech's site, but its not much more than what we already know: https://www.cowatech.dk/technology
A 5 dollar note says this Maxwell Daemon process has to be on par with reverse osmosis in terms of energy consumption, with the added complication of exotic chemicals.
All the dry regions are rather sunny, solar reverse osmosis sounds like a no-brainer.
Honestly the ideal contraption would be something that can harness the solar on the sea directly. That would be something especially if it is in the form of fishing nets at surface.
You don't need fresh water in the sea, you need it on shore.
The cost of maintaining anything in the sea is orders of magnitude above that on shore.
A cubic meter of fresh water costs about 3-4 kWh, desal plants are rather compact unlike the solar to power them and land tends to be expensive near shores so it makes no sense to combine solar and desal on the same site.
>Without knowing which one is being used, there's not much of a discussion to be had. We can say nothing about practicality or environmental impact, not to mention a host of other issues.
Wouldn't this information likely be patented, which could explain much of the press release secrecy?
A patent would mean it was publicly available information. You're thinking of a trade secret. In any case, this won't apply to an actual paper (and without a paper, what are we talking about?) because the paper is supposed to describe what is going on.
Possibly a trade secret as marvelous as the famous South Sea Bubble instance described by Charles Mackay:
But the most absurd and pre-posterous of all, and which shewed, more completely than any other, the utter madness of the people, was one started by an unknown ad-venturer, entitled "A company for carrying on an undertaking of great advantage, but nobody to know what it is." Were not the fact stated by scores of credible witnesses, it would be impossible to be-lieve that any person could have been duped by such a project. The man of genius who essayed this bold and successful inroad upon public credulity, merely stated in his prospectus that the required capital was half a million, in five thousand shares of £100. each, deposit £2 per share. Each subscriber, paying his deposit, would be entitled to £100 per annum per share. How this immense profit was to be ob-tained, he did not condescend to inform them at that time, but pro-mised that in a month full particulars should be duly announced, and a call made for the remaining £98 of the subscription. , Next morning, at nine o'clock, this great man opened an office in Cornhill. Crowds of people beset his door, and when he shut up at three o'clock, he found that no less than one thousand shares had been subscribed for, and the deposits paid. He was thus, in five hours, the winner of £2000. He was philosopher enough to be contented with his venture, and set off the same evening for the Continent. He was never heard of again.
This is pretty cool. I do organic synthesis in the lab right next to Jiwoong Lee, two of my good friends work on this project. It is not as amazing as the article makes it sound. Though low in energy it needs pressure and no one wants to drink the "diamine" compound, so added energy to remove this is needed. Give it 10-15 years.
How bio-active is the diamine, and how much remains in the potable water?
What happens to the CO2 afterward, if the salt is released? If this doesn't bind the CO2 permanently then its only about water desal. If it bound the CO2 it has dual-purpose.
You're asking the right questions! Even a few PPM of the diamine left in the water is going to be an issue either due to toxicity or if non-toxic, water quality (i.e. taste and perception of potability).
The "switchable" chelating agent is pretty interesting, but I haven't been close enough to know if this is groundbreaking or just an advancement of an exiting phenomenon.
I might be a major cynic here, but my guess is that this is really cool science and like a lot of cool, basic science, the researchers need to find a practical use for it. That helps translate "cool basic science" into "existing new technology".
My PI did it when I was in graduate school - we always talked about our new molecules as being potential cancer treatments when really the focus was on the basic organic chemistry. It's a lot easier to win grants saying you're developing "new anti-cancer compounds" than being honest and saying your research is focused on the development of "novel chalcogen compounds that undergo pericyclic rearrangements to form strained heterocycles".
A lot of deep groundwater (associated with gas, oil) is both salty, and gassy. If this technique is about converting mine waste to semi-potable for use in agriculture, or mining, and also uses the CO2 on-hand, and salt on-hand, its a virtuous industrial circle.
I'd hate it since it would be monetizing part of the mining industry I don't like, but it makes economic sense in the narrow. If diamine is bad, and gets into the food chain this wreaks longterm harm. If the liberated salt is bad, likewise.
I tend to "stop the mining" but understanding the pressure of water issues on mining and farming, there may be huge upsides here.
Most of water is used for technical purposes, not for drinking. Like washing hands, body or dishes. If it's safe for that, that would be huge achievement is this process is cheaper than conventional methods.
There's also other non-domestic uses that could greatly benefit from cheap large-scale desalination: Agriculture in arid regions. Sea water is not an option, but taste is not a primary concern.
We already have other methods of desalinating water, so not sure why this would be a step forward toward that idea. Also, a Stillsuit was not supposed to desalinate saltwater, but to purify urine and sweat, which contain many more chemicals than just NaCl.
I know I am way oversimplifying this. Last week I made a trip to sand hill road and had some fun. My most interesting takeaway from the trip wasn't any of those meetings, it was the many signs along I-5 between LA and SF. Yall need water, bad. I hope this is a potential solution.
I feel like this is the other way around. 95% of what I hear about California water shortage stuff has been from people outside of the state.
That and wildfires 500 miles away from me are about all people outside of the state ever seen to hear about. From the way they tell it it sounds like they're concerned that I'm going to die of thirst.
This article leaves a lot to be desired.
There is no compound called "diamine." Diamines are a class of compounds. Without knowing which one is being used, there's not much of a discussion to be had. We can say nothing about practicality or environmental impact, not to mention a host of other issues.
What may be happening here is the formation of a dicarboxamide, which then does something. That carboxamide formation is not likely to be reversible at room temperature.
The article has no link to the primary paper, where issues like this could readily be addressed, and there is absolutely no excuse to ever neglect to do so in 2020.