Slashdot Mirror
Revolutionary Scuba Mask Creates Breathable Oxygen Underwater On Its Own
schwit1 writes "With the Triton Oxygen Respirator, it might be possible to breathe beneath the surface of the water as if you were a fish. Requiring no bulky tank to keep your lungs pumping properly. The regulator comprises a plastic mouthpiece that requires you to simply bite down. There are two arms that branch out to the sides of the scuba mask that have been developed to function like the efficient gills of a marine creature. The scaly texture conceals small holes in the material where water is sucked in. Chambers inside separate the oxygen and release the liquid so that you can breath comfortably in the ocean."
Too good to be true.
So if it actually separates the oxygen what about the hydrogen? That's fuel.
If this is real it's more than just a breathing device, it's a low cost way to separate water into 2 Hydrogen atoms and 1 Oxygen atom. That is a much more significant breakthrough... then again that's a big IF.
Evidence please.
Revolutionary 3D render, more like.
also, breathing pure oxygen isn't so healty, so i'm wondering how they solve that without an external tank.
An artificial gill system for a human would have to be huge, and you'd have to move at a pretty good clip, too. There just isn't enough oxygen per cc to keep a human alive. This guy worked some numbers. http://deepseanews.com/2014/01/triton-not-dive-or-dive-not-there-is-no-triton/
Pretty sure fish gills work with dissolved oxygen, that's why the tanks need splashy things, to get the oxygen back in).
If fish were cracking apart water to breathe, we'd be researching it for energy use, like we do with plants and photosynthesis. Additionally, it'd eliminate advantage of aerobic respiration to split the water apart.
Wow, sent an e-mail as suggested when clicking on "use classic" banner, and got a fast response that addressed my msg
It doesn't sound like it's separating the hydrogen and oxygen atoms, more extracting dissolved oxygen. Fish do this, so it's within the realms of possibility.
I suppose it would be about oxygen dissolved in water.
just in case you were wondering, this is not a real device. Interesting concept but this would need to be considerably more bulky to drive enough water through the filters. About 200litres of water needs to be flowed through the device per minute. For a working prototype for comparison see: http://www.youtube.com/watch?v=D23HLDZvX2w which works with a compressor. The poster should make it clear that the device mentioned is not an actual device, nor likely to be feasible without a relatively large pump and power supply.
The scaly texture conceals small holes in the material where water is sucked in.
Good thing Ocean water is free of any particulate matter that might clog these tiny little holes.
It must have been something you assimilated. . . .
Perhaps you should read the linked arrticle instead of making a fool of yourself. ... sea water is H2O + dissolved gases. ...
Water is H2O
An artificial gill is used to fetch those gases out of the water.
So: it has nothing to do with your H2O - nitrogen equation.
The question if those "dissolved gases" are similar to air, or if it is indeed relatively pure oxigen and your concern applies, is still open.
Some people here already posted that this is only a concept and the gill is to small to support the needs of a human
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Fish don't split water into hydrogen and oxygen. Rather they extract oxygen dissolved in water. However it seems like there are significant theoretical barriers to such a device because humans need a lot of O2 and seawater only has 7ppm. So you'd need to pass 192 litres of water per minute over the gill surface to get 1 litre or oxygen.
http://en.wikipedia.org/wiki/Artificial_gills_(human)
As sea water contains 7 ppm oxygen, 1,000,000 kg (1,000 tonnes) of sea water holds 7 kg (1,000 short tons holds 14 lb) of O2, the equivalent of 5,350 litres (1,410 US gal) of oxygen gas at atmospheric pressure.
An average diver with a fully closed-circuit rebreather needs 1 liter (roughly 1 quart) of oxygen per minute.[8] As a result, at least 192 litres (51 US gal) of sea water per minute would have to be passed through the system, and this system would not work in anoxic water.
On the other hand
Another potential source of oxygen generation is plastron respiration.[10] A foam with hydrophobic surfaces immersed in water becomes superhydrophobic, which provides a water-air interface across which oxygen can diffuse into the foam. In nature, this method is used by some aquatic insects (such as water boatman, Notonecta) and spiders (such as Dolomedes triton) to breathe underwater without a gill. This method was experimentally proven by professor Ed Cussler on his dog
They don't say how big the apparatus was or what the flow rate was. There's an interview with Cussler here.
http://www.naturesraincoats.com/Experiments_Plastron%20Respiration.html
If you look here it seems like artificial gills do need a high flow rate.
There's an interesting New Scientist article about artificial gills here
http://s3.amazonaws.com/lcp/artedi/myfiles/Breathing%20in%20oceans.pdf
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
Very good point. Pure oxygen becomes toxic below 6 meters.
Also, looking at TFA and following the links, this looks like premium-class bullshit. No actual science, no pictures of the proposed device (just 3D renderings), this is just science-fiction.
for i in `facebook friends "=bday" 2>/dev/null | cut -d " " -f 3-`; do facebook wallpost $i "Happy birthday!"; done
Did anyone notice the poor English throughout the article?
The micro compressor operates through micro battery.
try
The micro compressor operates using a micro battery.
Nothing goes through the battery.
The micro battery is a next-generation technology with a size 30 times smaller than current battery that can quickly charge 1,000 times faster.
try
The micro battery is a next-generation technology with a size 30 times smaller than current battery and can quickly charge 1,000 times faster.
The original sounds like the current batter can charge 1,000 times faster.
I may be jaded but every time I see "Korean scientist" I am skeptical.
The one killer for the device is that we need to empty and re-fill our lungs to breath. There is no re-breather bag in the device to facilitate that and no way to get a proper air mixture from the device.
It is a hoax.
Most divers use compressed air. Nothing else.
Oxygen becomes quite a problem after 1.6 bar (or 1.6 atm) partial pressure. Exposure to 1.0 bar partial pressure O2 can be tollerated up to 5 hours. With 1.6 bar partial pressure O2 circa 15 min. There are also cumulative exposures limits to be followed. Divers doing deep dives or dives using compressed air with enriched O2 (Nitrox) use tables to find out their exposure limit to oxygen.
The maximum exposure limit for non-professional divers is commonly given to be 1.4 bar partial pressure O2, with short excursions to 1.6 bar in case of emergencies. If you are having 100% oxygen, you have 1 bar partial pressure at the surface, 2 bar partial pressure at a depth of 10 m (33 feet).
Deep/Long divers use special (and expensive) gas mixes with reduced nitrogen (replaced with helium) to reduce N2 narcosis effects. Very deep divers could go towards leaner O2 mixes to reduce the partial pressure. But when your are doing those types of diving your are not a sport diver anymore (at least not a typical one) and you will tune the gas mixture specifically for the dives. Technical and professional divers often du 100% O2 decompression at 6 m, which would be a 1.6 bar partial pressure decompression.
The scaly texture conceals small holes in the material where water is sucked in.
I think the /. editors have been sucked in.
nothing happens, its NOT a product, its a pretty 3D render and a VC bait,
Who logs in to gdm? Not I, said the duck.
Nitrox is oxygen-enriched for longer dive times - you can breathe less volume, and less nitrogen means you can go a little longer without decompression sickness. It's commonly used by recreational divers.
You might be confusing it with heliox, which is a bloody-expensive helium-oxygen mix. No nitrogen means no nitrogen narcosis and greatly reduced decompression issues, and a below-atmospheric oxygen concentration solves the oxygen toxicity problem. It's rarely used by recreational divers because it's hard to swim after you've sold an arm and a leg to buy some. Heliox is the domain of deep commercial/industrial divers.
No. If you breathe hyperbaric O2 for too long you will convulse. If you convulse under water you will drown.
There are rebreathers that involve a counter lung and maintain the breathing gas by scrubbing CO2 and adding pure O2 (and submarines do that as well), but the 'concept' device shown has none of those features.
... you get to dive for the 10 minutes that the "micro-battery" can provide power?
Seriously we go through this every time one of these artificial gills is announced, you need too high a flow rate for a battery to realistically be able to provide power for, so you end up with a system that lasts for far less time than a simple air tank could provide.
Seriously, this is a hoax. It's purely a design concept. Pure oxygen at dive pressures can kill. And there is no guarantee that dissolved gases will NOT be pure oxygen. Or you might be in an oxygen depleted area.
Read the comments on the design website by real divers concerning partial pressure, etc.
http://www.yankodesign.com/2014/01/03/scuba-breath/#comments
There's nitrogen dissolved in the water too.
It's still bogus though. A device like that couldn't pull enough oxygen from the water to sustain a human. Not even close. A functional one would have to be far, far larger.
Too good to be true.
Not at all:
Using a very small but powerful micro compressor, it compresses oxygen and stores the extracted oxygen in storage tank.
The micro compressor operates through micro battery.
No-one said it was a free lunch.
So if it actually separates the oxygen...
It doesn't. There's plenty of molecular oxygen dissolved in seawater. The fish know.
systemd is Roko's Basilisk.
Apart from the fact that the numbers just don't add up and you'd have to flow enormous amounts of seawater through the device, there are a couple of other problems:
- Breathing pure oxygen is fine at surface pressure, but it quickly becomes toxic when submerged
- You want the rest of your breathing air (21% oxygen or less, as you descend) to be made up of an inertial gas
- Lungs need to inhale and exhale to get the gas exchange in the alveoli to work, so you need a full lung volume of gas available at any time, not just the amount of oxygen required to run your body
- To get rid of CO2, you either have to release gas into the surrounding water, or scrub the CO2 using something such as soda lime
- Apart from the scrubber, you need to have these additional parts for it all to work:
1) some kind of counter-lung to allow for breathing movement
2) some kind of pressurized gas to increase the amount of gas in your lungs/counter-lung to compensate for the compression of it all at depth and to dilute the O2 content of the breathing gas
So, great idea. You have to lug a full rebreather system with you for it all to work, but luckily you can leave the 2 liter oxygen tank at home and use these fantastic gills instead - until the not-yet-invented next-generation battery powering the extremely powerful "Micro-Compressor" runs out of juice.
The only way this could work out to be something useful would be to hook up a major blood vessel to the device, allowing for gas exchange O2 CO2 between the water flow and the blood through the device, bypassing the lungs altogether. As an alternative, fill the lungs with a liquid (as in liquid breathing) and do the gas exchange between the breathing liquid and the water. Less messy that surgery.
A battery that is 1000x better than current technology would be even bigger news.
As others have said the device appears to be extracting dissolved oxygen, using filters that pass the oxygen but not water, so there wouldn't be much hydrogen present.
As it happens though I actually built a prototype electrolytic breathing device in middle school. There's no really cheap way to separate water molecules - at 100% efficiency it requires exactly as much energy as you would get from burning the H2 again, anything else would let you build perpetual motion machines. But with enough power something like electrolysis can be used to fragment the molecules, and it's easy enough to capture the gasses separately. The real problem is that pure oxygen is really nasty stuff at the pressures necessary for you to operate your lungs underwater, so you need to mix it with an inert gas to bring the partial pressure down to safe levels. And it would seem to me a filter process would have similar problems, though perhaps it can also extract other dissolved gasses along with the oxygen. If that's the case though it seems like you would want to monitor the gas mixture very carefully - swimming through a particularly oxygen rich or poor region of water could have nasty effects as your breathe-gas ratios change. Especially since we're not wired to be able to detect oxygen deprivation - only CO2 buildup. So long as our lungs can expel CO2 our first warning of oxygen deprivation is impaired cognitive abilities, which can easily pass unnoticed, followed IIRC by, giddiness and extreme judgement impairment, headache, and death. Oxygen toxicity is even more dangerous, it can cause seizures without any prior warning, resulting in near-certain death given the hostile environment.
You also can't really burn the H2 to recapture any energy, you need oxygen to do that. And you just gave the oxygen to that human you're keeping alive. You could possibly get some reaction going with the waste CO2, but I think there aren't a lot of candidate reactions to actually produce energy, CO2 seems to consistently be one of the end-products of efficient combustion. That leaves any O2 that passed through the diver's lungs unused, which may indeed be more efficient than trying to separate it from the CO2 for re-use, but after factoring in generating electricity from combustion you're talking maybe 30% of whatever percentage of oxygen was left unused, that could easily be such a small percentage of the initial energy that it's not worth considering.
My own red flag was
"- The micro battery is a next-generation technology with a size 30 times smaller than current battery that can quickly charge 1,000 times faster.”
So you're building a life-support device unlike anything seriously attempted before, and you choose to use an unproven next-gen battery system that's dramatically better than anything in use, but not so much dramatically better that hauling around a soda-can sized battery based on tried-and true tech couldn't deliver pretty much the same thing? This thing is, at best, a tech demo. And given the apparent total disregard for oxygen toxicity if it actually exists it's also a death trap.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
I make no comment on idiots posting ignorant tosh when they bloody well should know better if they've ever eg. seen a fish and wondered how it breathes.
But how the fucking hell did this get modded insightful?
I mean, I could understand interesting. After all, morons can be interesting if their stupidity reaches the right sort of rarefied heights. They become a curiosity and we can peer at them through the bars of the cage and be reassured that, no matter what we've done to the world and each other, nature can still have its way and throw up the sort of laughable dunce who really ought to have entered the Darwin award nominations long ago. We can meditate on the extreme tail of any probability distribution that keeps such a person alive for this long and reflect that life is like a box of chocolates.
But insightful? I can only suppose that we are meant to learn that no moderation system is perfect and the award of mod points does not automatically bestow wisdom.
Slashdot - News for Nerds, Stuff that Matters, in ISO-8859-1 Has just realised that beta makes this signature redundant
Well besides the fact that when you get a leak somewhere with a tank you still have time left (hopefully) to get to safety (depending on the size of the leak). A problem with the gills results in having no air whatsoever instantly. Dunno, I think I prefer tried and true technology in this case :)
One of the deeper linked articles has what looks like real photo's.
But still, the specs sound like a typical design student project; cool-looking device using fantasy technology.
"Oh, the tech boys will work out the tiny details like the battery that's 30x smaller and 1000x faster to recharge than current batteries."
I really want this thing to be real, but I'm missing the "fugly prototype" stage.
Slashdot social media options: AIM, ICQ, Yahoo, Jabber and Mobile Text. Why no MySpace?
I don't think you're going much deeper than that with this thing. The gas from the tank won't be able to keep your lungs open so you won't be able to breath. OK, there is a tank filled with compressed gas, but how much power would that micro compressor get from a tiny battery?
Anyway, the tank could have some N2 in it to start with so the problem could be mitigated.
Too good to be true.
Not at all:
That is to say, there are plenty of reasons why this thing is too good to be true, but GP's complaints are not among them.
systemd is Roko's Basilisk.
However it seems like there are significant theoretical barriers to such a device because humans need a lot of O2 and seawater only has 7ppm.
Indeed; fish deal with this by being low metabolism 'cold blooded' creatures. Humans, on the other hand, are mammals with a much higher metabolic rate and correspondingly higher oxygen use to support that.
Every time a sci-fi series has added 'gills' to a human to let them swim underwater I have laughed, the traditional make up for this, three flaps on each side of the neck, would not suffice for a fish.. let alone a human.
"Oops, I always forget the purpose of competition is to divide people into winners and losers." - Hobbes
Two miniature gas tanks a regulator and a vibrating device would simulate a working third generation underwater breather and would fool a few speculators into handing over the money.
What makes you assume the goggles have anything to do with the SCUBA mask? They're more a standard accessory, they certainly have precious little to do with breathing, that's done by the mouthpiece part of the mask. More importantly while it is a mouth-covering mask, it's not SCUBA
SCUBA = Self Contained Underwater Breathing Apparatus
A breathing apparatus that extracts oxygen from the surrounding water is by definition not self contained - swim into low-oxygen water and you're in for a world of hurt. It may be an UBA, but it's not SCUBA.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Breathing only oxygen is dangerous. Oxygen is toxic at high pressure.
With the device described here you'd still need a tank with nitrogen or helium and then you're back to having a device similar to a rebreather where you have to carry and mix your own gasses, which is extremely dangerous and even experienced divers get killed by it.
Now this technology is not completely useless and could enhance a rebreather by allowing more bottom time if it can be used to refill the oxygen tank or something on that line.
Why is this marked insightful? Mod this down! Fish gills separate oxygen that's been dissolved in water. They do not separate oxygen from the water molecule!
... and in the DRM, bind them.
Blog-based sources, poor grammar, CG images, and dodgy science apart, one of the sources identifies this as a project from SADI - Samsung Art & Design Institute. http://www.sadi.net/web/eng/home There's no sign of it (or anything) on their website, but it would make sense.
I'm pretty sure some people were telling Jesus the same thing when he was 33 years old or so. ;-)
Ezekiel 23:20
Haha what are you even talking about? It separates dissolved O2, not chemically bound O2. That is, assuming it works.
These types of devices have existed in the SCUBA community for quite a while -- they are known as rebreathers http://en.wikipedia.org/wiki/Rebreather . Usual rebreathers add O2 from an external tank and replenish (as oppose to air/nitrox from a regular scuba tank). This device is supposed to extract o2 from the water using an osmosis type of approach. Should be doable, but I don't know how it could keep up based on the design.
But dude, the micro compressor operates through micro battery! Seems legit.
After looking around the internet a bit, it looks like this is more of a design students wet dream project. His website details how was learning to scuba dive, and he found normal dive equipment 'bulky' and 'difficult to use', So he designed this device. There are no technical specs anywhere to be found only vague references to 'advanced batteries' and whatnot.
Finally, I ended up on a scuba diving board, where a kind soul who actually knew something posted the following (from wikipedia)
Artificial gills (human) - Wikipedia, the free encyclopedia
"They are generally thought to be unwieldy and bulky, because of the massive amount of water that would have to be processed to extract enough oxygen to supply an active diver, as an alternative to a scuba set.
As sea water contains 7 ppm oxygen, 1,000,000 kg (1,000 tonnes) of sea water holds 7 kg (1,000 short tons holds 14 lb) of O2, the equivalent of 5,350 litres (1,410 US gal) of oxygen gas at atmospheric pressure.
An average diver with a fully closed-circuit rebreather needs 1 liter (roughly 1 quart) of oxygen per minute. As a result, at least 192 litres (51 US gal) of sea water per minute would have to be passed through the system, and this system would not work in anoxic water.
These calculations are based on the dissolved oxygen content of water."
Another person noted that these figures are at 100% efficiency, and that is an improbable expectation meaning that the which means this system would have to be able to pull the output of a fire hose through itself. This means that you could probably use the thing to propel yourself through the water at a high rate of speed. Also, I don't want to put a 'revolutionary new battery' with that much potential energy *practically in my mouth*. Now, even if you managed 100% efficiency, and kept the water flow to that 'paltry' 51 gpm, and devised some way to make it not jet you off into the deep, your left with one more problem. The damn thing is electric. And even with the best batteries on the market, your going to get mere minutes of use out of the thing at that size. Compare that to the hours a diver can stay down (with proper mixture and training) and this device is obviously wishful thinking. Well done /. editors, you trolled yourselves.
I've decided to Diversify my Holdings. I've divided my cash between my left and right pockets, instead of all in one.
This doesn't electrolyze water into H and O. It acts as a semipermeable membrane that allows gas exchange between the air inside and the water outside. So you don't get "pure" O2, you get more-or-less normal air.
You have a higher partial pressure of CO2 inside, so it selectively moves out; Similarly, you have a lower partial pressure of O2 inside, so it moves in. Only the inconvenience of having enough surface area prevented something like this before - You need on the order of 70m^2, with sufficient movement of both the water and air to make something like this viable. Apparently nanotech has advanced to the point where we can pack that into a pair of 2x8 inch tubes.
90 liters of water per minute, at 100% efficiency, at the surface where oxygen is most abundant. So, at 50% efficiency, at 30 feet, yes probably 400 lpm. Minimum 1/4 HP pump and probably more like 4 HP just to handle O2 extraction. From a battery about the size of your cell phone battery? But thats just one of a hundred things wrong with the idea. Its complete BS.
I'd like an interview with his dog
Wow
such breathing
so wet
However, a pool builder who might want to put a technician below the surface of pool water for 5 - 15 minutes to work on a repair might not want to pay for the SCUBA training and maintenance.
I'd look at a snorkel, personally.
This product might also work.
Very good point. Pure oxygen becomes toxic below 6 meters.
Also, looking at TFA and following the links, this looks like premium-class bullshit. No actual science, no pictures of the proposed device (just 3D renderings), this is just science-fiction.
While I don't know if the device exists, we've been researching similar techniques since the 60s to help cystic fibrosis patients. The major obstacle I would see is not can the dissolved oxygen in the water be extracted, we already know it can, but can it be extracted fast enough and in enough quantity to enable a person to use it in lieu of a scuba tank?
Importantly, if there's little to no dissolved air in the water, there's no air to breathe as there's nothing to extract. Sea conditions that kill fish and other marine life would be just as deadly to someone using this technology.
Do not look into laser with remaining eye.
Is anyone else suspicious of this announcement? Every article I can find is very vague on exactly how this is supposed to work. The one article I found that has a hint was it mentioning a filter with pores smaller than a water molecule. This infers they are extracting oxygen dissolved in the water. I wonder how much water one would need to pass through. Fish are cold blooded, and therefore have a lower metabolism than mammals. So we would need to filter a lot more water than a typical fish to make this work.
That was my thought too, but, it should be possible to detect such conditions. The better question is where the threshold is. There may be conditions that fish and marine life would survive where this device may not produce enough air for a human.
I imagine more of a hybrid system where this provides the normal breathing, and a backup tank only for emergency or low oxygen conditions. Even in a condition where it only provides half the oxygen you need, it could still reduce demand on the air tank allowing you to have a smaller tank than you would need otherwise.
"I opened my eyes, and everything went dark again"
Sure there's video. Haven't you seen Star Wars: The Phantom Menace? The device is the same thing Qui-Gon and Obi-Wan used to get to the underwater city. So it must be real.
Here's a nice analysis:
http://deepseanews.com/2014/01/triton-not-dive-or-dive-not-there-is-no-triton/
Basically, it would take processing 24 gallons of water per minute with 100% efficiency (unlikely) to provide a human with enough oxygen. No way can this work as described.
However it might possibly be a start. When humans breath they don't use all the oxygen in the air up. so one could reprocess that air (as rebreathers do) and then supplement that using this device to make a better rebreather.
Some drink at the fountain of knowledge. Others just gargle.
I'm pretty sure Mary said the same to Jesus...when he was 14 years old. It probably didn't mean the same thing back then.
Hey, that had to be a rough time for him. A teenager that can turn water to wine is automatically banned from all swim meets... nothing funnier than seeing the whole team floundering about in 40,000 gallons of chardonnay!
Being disqualified from the Science Fair for telling people that God was your Dad... and then bringing corpses back to life as proof.
Asking Joseph if you can borrow the camel for junior prom and being told to "Go ask your REAL Dad!"
No, not an easy time at all...
You have the right to remain sentient. If you give up the right to remain sentient, you will be elected to public office
(patent pending, so don't even think about it)
"Anyway, the tank could have some N2 in it to start with so the problem could be mitigated."
You don't want to be breathing any N2 at depth. Ever heard of the bends.
They used to use a Helium mixture for deep dives, I am not sure what they do these days
According to one of the sources in the article this is still just a concept, not an actual product that exists. When it's a real product then we can get excited, but for now it only exists in photoshop.
my karma will be here long after I'm gone
Very good point. Pure oxygen becomes toxic below 6 meters.
A simple solution is to start with the air already in the diver's lungs, with will be 80% nitrogen, then recycle it while stripping out the CO2, and adding in the O2 from the "gills". Humans typically inhale 21% O2 and exhale 16% O2. So if you don't recycle the exhaled air, and just vent it instead, you are wasting most of the O2. For deep dives, start with a breath of argon instead of nitrogen.
Yup.
Just looking at the design, other than saying "micro" a few times like waving a magic unobtanium wand, they made the impossible into a photoshopped picture.
It's a neat idea, and does have some scientific basis, but it leaves an awful lot to the imagination of the person who made the photos. I guess that's the fun of concept science. Maybe someday someone will make it real.
I did a little searching, and found "Like-A-Fish", which does appear to have something. The wiki page has more details. It requires a 1Kg battery, which lasts for one hour.
http://en.wikipedia.org/wiki/Artificial_gills_%28human%29
http://www.likeafish.biz/
So, the whole thing is made from unobtanium and unicorn farts.
Serious? Seriousness is well above my pay grade.
Fortunately most divers take up the sport because we like to look at fish, not because we enjoy bathing in agricultural runoff and/or sewage. Ergo, not a lot of recreational diving in oceanic "dead zones".
"Anyway, the tank could have some N2 in it to start with so the problem could be mitigated."
You don't want to be breathing any N2 at depth. Ever heard of the bends.
They used to use a Helium mixture for deep dives, I am not sure what they do these days
Outside of specialized mixtures for deep dives (well beyond the usual recreational dive limit of 130 feet), divers breathe either ordinary compressed surface air (80% nitrogen), or nitrox/EAN, which is a mix with increased oxygen content. Interestingly, the increased oxygen in nitrox is not there for its own sake (i.e. with healthy lungs there is no physiological benefit to breathing an increased fraction of oxygen), but rather as a cheap way to displace some of the nitrogen, allowing longer bottom times before having to worry about decompression stops or getting the bends.
Dive organizations love to push nitrox since it is another certification and an upcharge on fills from a dive shop, but in my experience it is used by less than 10% of the divers I have seen.
The dives Ive seen rebreathers used on were the Great Blue Hole and Terneffe Reef in Belize. If you dive, they should both be on your bucket list! And, they are both dives that taunt you with the bottom rows of the recreational dive limits. I spent 7 minutes at 145 feet, where my dive computer gave up beeping warnings at me and just sulked for the remainder of the dive. It was a great opportunity to experience nitrogen narcosis in a fairly well supervised trip. This page here shows the dive profiles; escorted trips dive the south grotto which pushes the 110' limit just getting there. Rebreathers give you a lot more flexibility to explore, with better bottom times.
A problem using Triton here is all the water is anaerobic, there is no oxygen and thus no sea life below the thermocline, and nothing for the Triton or LikeAFish to extract. Conditions like that can happen unexpectedly anywhere on medium depth dives. Thermoclines shift and below them there is little interaction with oxygenated surface water. So Triton et al would presumably just shut down suddenly and without warning or any reserve even during shallow dives. Not good. Carrying a pony bottle would be mandatory.
Thanks for the link on other dissolved gasses. Nitrogen is available then at ~150% by volume of oxygen. Lets make some assumptions: Troton could use the same membrane for both oxygen and nitrogen; that they both extract 50% efficiency. You need 12L to get a breath of O2 but 40L to get the nitrogen. At 15 bpm we're up to 600 lpm to process. at surface pressure. At 60 foot depth thats 3 atmospheres, so 1800 liters per minute! A sump pump at 1/4 HP does about 80 lpm at no head/pressure, so 5 HP if the triton needs no pressure for the membrane, which I guess is does (reverse osmosis needs about 50psi) so we are probably close to 20HP to run it. Thats a gas-burning outboard motor, not a pair of Duracell AA's and a few CC's of motor.
You and I between us have almost assuredly done more real work on the Triton than the clown that "invented" it; a college sophomore with no engineering background except a working knowledge of Solidworks and access to a 3D printer, and a single escorted rec dive to his credit.