There is nothing trivial about ocean chemistry! Many a salt water
aquarium owner knows this all too well. Thanks for the link, Oliver.
On 08/02/2013 14:01, [email protected] wrote:
Dear Oliver,
I think it is not so trivial as you wrote - different steps of
reactions which you wrote are prefered at different pH.
Please for example see this web link and graph on the bottom of the
web page:
http://ion.chem.usu.edu/~sbialkow/Classes/3650/Carbonate/Carbonic%20Acid.html
<http://ion.chem.usu.edu/%7Esbialkow/Classes/3650/Carbonate/Carbonic%20Acid.html>
best wishes,
Lidija
On Friday, 8 February 2013 11:52:15 UTC, Oliver Tickell wrote:
Unfortunately my confusion is only deepening ...
There is more CO2 in the np system - but I thought it was meant to
be H2CO3, not CO2.
There is HCO3- on the nickel - but no bicarbonate in the system.
If the solution is acidic (ie, there is lots of H+ in the
solution), where is the acidity coming from if not from
dissociation of carbonic acid:
H2CO3 + H2O <=> H+, HCO3- <=> 2H+, CO3= ?
But you say only carbonic acid present.
Oliver.
On 07/02/2013 23:51, gaurav bhaduri wrote:
Dear all
Thank you for your interest in our work and your comments. To
clarify some of the misunderstanding in the process conditions
that I'd like to clarify. When we bubble CO2 in water with and
without the nanoparticles, we observed that there is more CO2 in
the nanoparticle system than in pure water. We also observed that
there was HCO3- ions on the surface of the Ni nanoparticles
surface, we thus explained that this enhancement could be due to
adsorption of the HCO3- (from the acid) onto the Ni surface. We
in no place claim the formation of CO3-- ions, to be clear on
this point the system we are addressing in this article is at a
acidic pH (<5). Thus there is only carbonic acid species present
no bicarbonate or carbonate system as they exist at higher pH values.
Now coming to the point of mineralization. We are currently
working on this (as explained by Dr Siller, previously) and would
like to use silicates as our metal source (Ca2+ or Mg2+).
Regarding the confusion of sea or oceanic system. We do not tend
to imply the use of Ni nanoparticles in the ocean or any thing
around it. The relation with sea urchin (or the marine
environment) is just that, the use of Ni to study the hydration
reaction we triggered by the studies done on the sea urchin by Dr
Siller and my other colleagues.
Our major application is to use this system as a satellite unit
(plant) to an operational point source emitter (for example a
power plant). The carbonate mineral thus produced would be used
as landfill or in any other useful application. As mentioned
above, we are working on the use of silicate sources
(terrestrial) for the source of the alkali earth metals (Ca2+ or
Mg2+), thus ruling out acidification of the ocean or any relation
to the ocean.
Hope I was able to explain the application of our technology. If
you still have any doubts, please feel free to ask. We will try
our level best to clarify any confusion.
Thanks to all
Kind regards
Gaurav
On Thursday, 7 February 2013 18:49:41 UTC, Greg Rau wrote:
Thanks for responding. I really don't follow this. If I have
a beaker of water fully equilibrated with air (CO2) and add
your Ni particles, you are saying that more HCO3-
and ultimately CO3s will spontaneously be produced. This
won't happen unless thermodynamically favored, and if that
water if fully equilibrated with air CO2 there is no
thermodynamic condition that will force a change in the C
chemistry. If your Ni particles are somehow consuming H+ or
producing OH- then you've got a driving force, but you still
need a source cations to make CaCO3s (am very interested to
learn how you cheaply extract cations from silicates.)
Otherwise, adding a catalyst to a system at thermodynamic
equilibrium does nothing. On the other hand, adding
something to seawater that overcomes the natural, chemical
inhibition of abiotic CaCO3s precipitation could really cause
some serious precipitation and CO2 injection into the
atmosphere. No?
-Greg
From: "[email protected]" <[email protected]>
Reply-To: "[email protected]" <[email protected]>
Date: Thursday, February 7, 2013 8:32 AM
To: geoengineering <[email protected]>
Subject: [geo] Re: Nickel nanoparticles catalyse reversible
hydration of carbon dioxide for mineralization carbon capture
and storage - Catalysis Science & Technology (RSC Publishing)
With presence of Ni we have increases at the same
time trapping of CO2 and increased the rates of conversion to
carbonic acid on room temperature and on the atmospheric
pressure.
We still working to find the best mineralisation pathway - we
will use silicates (magnesium calcium silicates) as a source
of Ca2+ or Mg2+.
While nickel nanoparticles are toxic as already mentioned in
the paper we do not propose to spread this around in the
enviroment but to have local disposal next to power plant or
industrial plant.
We made brief cost - 8$ per ton of CO2 if we can recover Ni
99% yield based on current price of nickel.
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