Notes About Video # 3 Link Below)
- Video 2 is 16 minutes long and shows the 2nd
Prototype HENSI Reactor immobilizing Golder &
Associates Iron/Palladium nano-catalyst for
subsequent on-line, flow-through uses in any
catalytic scenario. This catalyst was chosen
because it is especially effective for in the rapid
breakdown of any of ~39 recalcitrant chlorinated
hydrocarbon water pollutants ubiquitous to our
(often otherwise potable) groundwaters. As
such, when HENSI - immobilized on a large scale,
Fe/Pd nanocatalysts could be quite effective for
ex-situ, high-throughput, Point-Of-Distribution, on-
demand remediation-to-potable-quality of
hundreds of US aquifers.
- For initial loading into the HENSI reactor, the
nanocatalysts are added to 1 gal water (in a
sump bucket), which is then circulated through
the HENSI reactor and back into the bucket at
~1GPM
- As the HENSI reactor is energized, the
nanocatalysts (in solution) being pumped through
it are immediately immobilized in the unit
(removed from solution and captured in an
homogeneous distribution within the reactor), as
evidenced by the HENSI discharge stream
immediately becoming clear
- In the experiment, in order to keep the system
volume at 1 gallon (no water source or drain was
available) the clear discharge is sent back into
the sump bucket, and mixed with the turbid
nanocatalysts solution
- Therefore the solution in the bucket slowly
clarifies, asymptotically reaching the clarity of the
discharge stream, but note that the discharge
stream remains clear throughout the capture
process
- Once the bucket has reached a clarity under
about 1 NTU (about 3 minutes) the reactor is fully
charged, The system would be put into normal
operation: the (polluted) process fluid would them
be routed through the reactor, exposing it to the
immobilized nanocatalyst to achieve the desired
breakdown of carcinogens to benign species -
online remediation, often to potable quality water
in this one unit operation.
- The video, however, continues with the de-
energizing of the HENSI unit to release the
nanocatalysts from their immobilized state, back
into the flowing solution. This is done only to
demonstrate the reversibility of the process: In
actual practice, this step would only be carried
out after the catalyst was spent, or for catalyst
regeneration / recharge operations. The video
then repeats the entire process of capture and
release, just for good measure. The second
time, however, I actually route the reactor
discharge into a clear plastic container, that the
viewer might see that the reactor discharge
stream is unmistakably free of nano-catalyst,
indicating that the immobilization is thorough and
complete
- It is important to note that I have yet to approach
the actual capacity for this (yet-to-be-optimized)
HENSI unit: In the first video I immobilize 20
grams of nanocatalyst within the HENSI reactor.
In the second video I immobilize approximately
100 grams in the same reactor, for a 'Loading
Density' of [100 g catalyst x 30 m2/gram / 14in3
=~ 200 square meters of catalytic surface
area per cubic inch of reactor volume, and
much greater 'loading densities' may well be
attainable once the systems are optimized.
- The important point is that the combination
of this density of catalytic area per unit
reactor volume (with all the catalytic surface
area exposed to the bulk reactant), the
complete and thorough nature,and
reversibility of the immobilization at low
pressure drop, complete scalability and
modularity, and the low capital and
operating costs will allow HENSI to truly
usher in a new era in nano-catalysis for any
application which can benefit from ex-situ
processing.
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