[Terrapreta] Fwd: ammonia and charcoal

[Brian Hans]

Gerald et al,
   
  Just a few comments here thats been running around in my head as of late. 
   
  As Ive said before, Charcoal is a strong hydrophobic. But when one water soaks the material for a good amount of time, it will take up a huge amount of water in the pores. Even tho the material feels dry on the outside, if you put the charcoal on a piece of sorptive paper, it will drain for hours (depending on surface area size?) in a slow drip until virtually bone dry. 
   
  A cool experiment would be to have 10 different size pore and/or surface area and/or density and/or Ash% and/or...charcoal material and measure uptake vs release of water.  
   
  Another comment here, charcoal doesnt seem to act in reverse. If you completely dry a piece of charcoal and then set it into a small puddle of water for a length of time, it will only uptake into the saturated material. 
   
  Brian
   
  
Gerald Van Koeverden <vnkvrdn at yahoo.ca> wrote:
  Fresh biochar exhibits strong hydrophobic properties.  But biochar that has been sitting around in the open exposed to rain is totally opposite.  When I dry this biochar out, and then re-expose to moisture, it soaks up water like blotting paper.    

  This change in physical property must be a reflection of chemical changes - at least on the surface of the pores.  Has anybody seen a study of how charcoal/biochar changes chemically over time, comparing the changes in wetted versus dry-stored.
  

  This could be important, eg in using it as an ammonia absorber in making compost.  Charcoal that has been soaked first in water, might have a very different ability to act as a nutrient "sponge."
  

  Gerrit
  
  
  Begin forwarded message:

    From: Gerald Van Koeverden <vnkvrdn at yahoo.ca>
  Date: February 7, 2008 10:41:00 PM EST (CA)
  To: terrapreta Preta <terrapreta at bioenergylists.org>
  Subject: Fwd: ammonia and charcoal
  

The nature and strength of the electrical charges inside the charcoal particle, might also be important for anchoring microorganisms in it as a microhabitat.  For example, bacteria tend to have a negative electrical charge.
  
  Begin forwarded message:

    From: Gerald Van Koeverden <vnkvrdn at yahoo.ca>
  Date: February 7, 2008 5:04:55 PM EST (CA)
  To: terrapreta Preta <terrapreta at bioenergylists.org>
  Subject: Fwd: ammonia and charcoal
  

to follow up on ammonia absorption in charcoal...  

  it's interesting to note that there is no direct relationship between charcoal porosity and ammonia absorption.  In fact, the absorption of low temperature-made (400 degrees) bamboo charcoal treated with a dilute sulfuric acid is twice that of activated charocal which has a pore surface area eight hundred times greater. 
  

  http://jhs.pharm.or.jp/data/52(5)/52_585.pdf
  

  Gerrit
  
  Begin forwarded message:

    From: Gerald Van Koeverden <vnkvrdn at yahoo.ca>
  Date: February 7, 2008 3:51:02 PM EST (CA)
  To: terrapreta Preta <terrapreta at bioenergylists.org>
  Subject: ammonia and charcoal
  

      Could chemical interactions between ammonia and charcoal be the initial key for how charcoal is gradually transformed into that found in terra preta?  

    "Australian researchers have discovered a cheap and simple way to make sheets of carbon just one atom thick.
  Their finding has implications for a range of developments from solar cells to bionic ears.
  The sheets, known as graphene, normally stack together to make the kind of graphite used in pencils.
  But when separated, graphene sheets have extraordinary electronic, thermal and mechanical characteristics, says Gordon Wallace from the University of Wollongong in New South Whales, Australia.
  "People have known that if you can separate sheets of graphene from graphite you can get some pretty interesting properties," he explained.
  Most researchers thought creating these sheets in a cost-effective way was an insurmountable challenge, due to their strong tendency to clump together. But in the journal Nature Nanotechnology this week, Wallace's team shows stopping the sheets from aggregating is actually a fairly simple matter.
  The Australian team did not use chemical stabilizers to keep the sheet apart. Instead, they used water with some ammonia added to increase its pH value, making it more alkaline.
  "It's actually a really simple discovery but with fairly significant implications," Wallace said.
  "It's a matter of understanding that simple chemistries can be applied to graphite sheets."
  Increasing the pH of the water raises the electrostatic charge on the graphene sheets, he explained, making sure they repel one another instead of clumping together.
  This low cost approach raises the possibility that scientists could produce large amounts of stable graphene that could be used in a range of settings.
  "The very unusual electronic properties of graphene sheets means they could be used in solar cells or new battery technology," he said. "Because of the biological affinity of carbon, they might also be useful as electrodes for a range of medical bionic devices such as cochlear implants."
  



    http://dsc.discovery.com/news/2008/01/29/nanotech-carbon.html
  

  Ammonia and water - being the main ingredients in urine - could easily have been added to charcoal by native Amazonians.
  

  It is apparent that ammonia changes the chemical nature of carbon molecules.  To effect charcoal, it would need transform only the innner pore surface area of the charcoal particle to dramatically change its CEC, without affecting its overall physical structure.
  

  This afternoon, I added a saturated solution of ammonium nitrate to biochar to compare with a control of pure water mix.  Once I let it sit for several days, I'll dry out the samples and then see if I can see any difference in how they re-mix with water.  
  

  Unfortunately, I don't have any lab equipment to then test to see if the CEC has changed.  I'm trying to think of simple tests I could do to find out what, if any, properties have changed, for example:
  

  a)  putting a large drop of water adjacent to the pile of char to see how quickly the char sucks it up as a test to see whether its hydrophobic properties have changed.
  

  b)  using the two samples as a filter for various aqueous solutions to see if there is any difference in what they filter out of them...
  








_______________________________________________
Terrapreta mailing list
Terrapreta at bioenergylists.org
http://tech.groups.yahoo.com/group/biochar/
http://terrapreta.bioenergylists.org
http://info.bioenergylists.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /attachments/20080209/96eceae4/attachment.html