Hydrothermal carbonization and other nano particle work

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  • Quick math. 
    All charged to five volts.
    farads: Joules:
    1000 12500
    2700 33750
    10000 125000
    100000 1250000
    etc.

    A normal cap you'd find in your computer:
    charged to typical 250v

    100microfarads 3.125 

    You can see that there's just an enormous amount of power potential there.
  • We're using mechanical/chemical exfoliation of graphene. So top down approach. Works well for what we need and is dirt cheap. Basically you throw graphite powder in a blender full of a mix of acetone and water. leave it running for a few hours and voilia big tub of graphene in solution
  • Are there any numbers in terms of the yield and purity?
  • It's very very high yeild. Don't have numbers off the top of my head and the purity is good since you only add the one starting material. We add the graphite to 30% hydrogen peroxide and that exfoliates it down to the size we need before the blender. There's no side reaction since it's not a reaction its actually a physical transformation as you're just separating the sheets of graphite to get the grephene 
  • I am curious, and please let me know if I should make a thread out of this, what is the speed at which a graphene supercap can store energy? TheGreyKnight mentioned up above that 1megafarrad equates to a small bolt of lightning and chironex you mention that there is a 3mF supercap. I had a discussion with my physics professor about the possibilities of finding a way of using lightning as a power source. There is a huge amount of energy in every lightning bolt and we do have the ability to attract them to specific locations. i.e. lightning rod. My professor said that one of the largest obstacles was the speed at which the transfer of energy would have to be and that there are no current transfer mechanism that can accommodate. Would a supercap be a viable possibility? 

  • @chironex I'd be very interested in getting hands on a sample of the supercaps. Even a tiny one would be a great experience to have as EE.
    What other specs do they have. Like ESR and self discharge characteristics, max pulse and ripple current, energy density (gravimetric and volumetric), max operating temperature, lifetime etc.
  • @Tellari not quiet. it's a massive amount of power but not quiet that much. A lightning bolt generates billions of joules. this can hold a few million. As to transfer speed that largly has to do with how much voltage is sed to charge it but you can get a good charge on it from 5 minutes at 5 volts. enough to power a light for probably 2 hours. I say probably cause the demo was stopped after over an hour cause they got bored. 

    @thomasegi unfortunatly I wont have that sort of data till we build one. For now I only have the other guys research to work on and he hasn't released that info. But it's mainly since it's such an important project and they don't want people stealing it before they can finish theirs. But I will certainly let ya know when i find out. So when we make the tiny ones assuming they aren't hell to make I may start offering them on the site for people to play with as we improve them. Or if they're stupid cheap then send out a few for testing. who knows.

    Also fun news! Just heard from awstin. We have confirmation, we successfullymade iron nanoparticles capped with carbon which can be removed from solution with a magnet. This is so cool. We'll be trying the quantum dot stuff tomorrow.
  • @chironex Thanks for the info. I understand that a lightning bolt is an amazing amount of energy. I mainly asked because capturing even a fraction of a bolt would not only be a step in the right direction but also it could potentially assist in solving energy problems. 

    How long do they take and how complex are they to build? 
  • The lightning bolt story isn't as easy as it sounds. You need more than just a giant capacitor. You need a giant ultra-high voltage capacitor with extreme current handling capabilities. Ranging in millions of volts and 6 digit ampere. Getting that into a cap requires more than just a 5V capable capacitor. You need extremly low resistances all the way from your lighting rod to the capacitor surface to prevent capacitor voltages from reaching dangerously high voltages and arcing. Otherwise you'd need a cap that can withstand millions of volts. Some quick math on dielectric strength and the used materials indicate rather thick insulation/spacing between the surfaces is required.
    Sounds discouraging but my EE-spidersenses are tingling. If anyone was to try this I'd recommend to put the cap into a blast-proof environment and yourself behind several cm of blast-proof glass/concrete.
    And even if you get 100% yield from a single strike you get electrical energy worth 280€. Put a 1.5kW Solar rig on your roof and you'll get the same.
    The idea is cool, but probably neither working nor worth the trouble.
    If you'd still manage to do it. I'd recommend to put it into an electric plane and power it by flying through thunderstorms.
  • edited June 2015
    So here it is folks a full write up of the process we used and a video of the particles. We're seeing if we can make friends with one of the professors so we can use their electron microscope. 

    write up (fair warning page formatting got a bit screwy. working to fix it. should be fixed shortly)


  • The lightning idea does not sound easy to me, more like interesting. I appreciate the insight into requirements needed. I am just starting into my EE/CE degree program. This will be something I keep in my sketch pad.

    @chironex glad you posted a write-up. Subject is really interesting and I look forward to reading about the development of your delivery system.
  • Oh and in addition to just the engineering challenges presented by the rig, there's another, more simple, statistical problem you need to overcome. Is the cost of building the rig going to be overcome by the power which might not be generated consistently(lightning isn't terribly predictable, and the tools we have to make it more predictable use more power than they create.
  • Please move all further lightning discussion to a new thread. It's really nota  feasible idea but if you'd like to delve deeper please do it elsewhere. this thread is for discussion of nanoparticles
  • watched the video. Those particles are mesmerizing. I wonder if they can be tricked to build a floating blob with multiple helmholtz coil pairs.
  • Link should be fixed now. I changed which blog plugin i was using so it screwed thing up. should be fixed now.
  • As to a floating blob i'd very much like to try something like that if possible. Also a preliminary online search point to the particles being safe for biological use but they'll need a fair bit of testing to prove it.
  • edited June 2015
    Made another quick video about the particles. I've got them in a nice vial now and we made a bunch more. Enough people asked me about it that I'm making a page on the site which I'll post a link to later for those who want a vial of these as a desk toy. Or if you'd like to try an experiment with some, whatever your reason. 

    Felt artsy and got a macro lense set up to see the particles in the water better. Made a neat video

  • How much do you think a vial will run?
  • Prices are listen on the site but for a fairly raw solution 6 bucks, if you want a vial of particles with a more consistent size and very few contaminants then it's 10. Plus the 5-6 bucks it'll cost to ship to you.
  • So, how'd you separate the bigger particles from the smaller ones? And is the consistency of the heat very important?
  • edited July 2015
    If you hold a strong magnet to the side, you can tip out the liquid while holding onto anything that's magnetic. So we do that, then refil with water, shake, repeat. Only the really magnetic particles stay behind and since particle size determines magnetic attraction, only the bigger particles which respond the fastest remain. 

    We're still exploring the various variable to see what effects them. We'll also be doing some chemistry with them tomrrow to see if we can make them hydrophobic or functional in some way. 
  • Would it be possible to substitute the iron chloride with another metallic chloride, like Gold Chloride, to produce carbon capped gold nano-particles, or a similar molecule? I believe I read something about black tea being used along those lines.
  • Well we tried copper chloride and tea and it seemingly did nothing but I'm gonna retry it tomorrow. We've been doing graphene oxide a lot lately which has been interesting. It's easy to do and forms such a perfect layer its neat. The only thing with other nano particles is, how do you test for them? what is their purpose? the iron makes sense since it's magnetic but what about copper? you can't use it's catalytic properties anymore. it can't react either since the shell prevents that, at least in theory. My only thought is maybe remove them from solution afterwards and compress and sinter them into an interesting material or use them as seeds for nanotubes or soemthing. I dunno. 
  • How about conductivity?
    Copper capped particles could be suspended in an ink medium and make a decent conductive ink, perhaps?
  • When we tried the copper, the solution was still blue. i'll have to try it again and see but the particles may be blue which if conductive could be interesting. A colored conductive ink. something not black would be cool. 
  • One possible way of removing the carbon caps would be to heat the nanoparticles in an oxygen-rich environment. Might strip the carbon off to form carbon dioxide or monoxide, leaving you with an oxide or... Somethin' else. I'm not a professional chemist, so I've not the slightest idea how the metal ions would react.
  • As for the usefulness of other nanoparticles, if nothing else, you could make some sick thermite. And from what I've read, copper nanoparticles are brown or black. Guessing a lot of the copper chloride remained unreacted. 
  • Probably. As to how they'll react, no clue. Probably burn off the carbon and reform the metal oxide. 
  • edited July 2015
    Well, if we added Ascorbic Acid (Robert Murray-Smith mentioned something about that in one of his videos) to the mix at this point, what do you suspect would result? Straight up metal nano-particles, perhaps?
  • Honestly I don't know. if you were to run it with just citric acid you'd end up with fluorescent blue nano dots. No clue what'll happen if you did it with a metal in there. That said in every run we've done i've found a small amount of magnetic material so it's possible that these particles are quite common. 
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