On Jun 10, 2007, at 5:35 AM, Michel Jullian wrote:
The question is, won't it also produce nasty stuff considering the
carbon isn't as inert as platinum?
It may be the commercial problem is more along the lines of needing a
catalyst to produce the powerful MIOX combination. I don't think they
had to prove the device safe, merely effective. However, any
dissolved nitrogen or nitrates, present almost everywhere, could
indeed cause the formation of the toxic cyanide ion CN- if carbon
electrodes are used.
I've often thought an electrode free device might work even better
than the Pt ones. The idea is to capacitively couple to the
electrolyte. Switching polarity fast enough can avoid, momentarily,
the need to overcome the potential drop due to the 2 molecule thick
interface at the anode and cathode. The water plus dielectric covered
plates would provide (be) the capacitance in a resonant LC circuit.
Consider the vendor supplied reactions. Anode reactions:
2 Cl- = Cl2 + 2e-
2 H2O = O2 + 4H+ + 4e-
HOCl + H2O = ClO2 + 3H+ + 3e-
O2 + H2O = O3 + 2H+ + 2e-
The major reaction at the cathode is electrolysis of water:
2 H2O + 2e- = H2 (gas) + 2OH-
The electrolyte can undergo hydrolysis with no net charge transfer:
Cl2 + H2O = HOCl + Cl- + H+
HOCl = OCl- + H+
It is also notable that any chain of reactions that accomplish:
2 H2O + O2 = 2 H2O2
or:
2 H2O = 2 H2 + O2
need not involve a net electrolysis current, so these reactions
should be pushed. The major products should be HOCL and H2O2.
The anode and cathode reactions would still happen, but the electrons
would merely be transferred back and forth to the ceramic surface,
and thus the surface reactions would tend to reverse.
An AC cell might be driven at less potential and still achieve the
desired reactions if the frequency is high enough or at least the
potential reversal fast enough. The key to success may be finding a
ceramic with desirable catalytic effects, or at least which would not
be eaten up in the process. I expect cavitation might be a problem.
This is all pretty much a fantasy with regard to the pen. However,
for bulk sterilization in well houses, it seems to me the ability to
efficiently push enormous currents through the water, using
resonance, might make for effective sterilization. The biological
contaminates would even absorb power, and provide surfaces for
formation of the decontaminates. The low operating voltage would be
very safe, but it might be necessary to provide good electronic
filters on the mains to avoid sending electronic noise into
residences. It might even work efficiently for producing MIOX in a
brine cell. I don't know. Maybe this is all just idle dreaming.
Regards,
Horace Heffner
