Tech Briefs Magazine - April 2021 - 56

SPINOFF

Spinoff is NASA's annual publication featuring
successfully commercialized NASA technology. This
commercialization has contributed to the development
of products and services in the fields of health and
medicine, consumer goods, transportation, public safety,
computer technology, and environmental resources.

Odor-Eliminating Shoe Inserts Rely on NASA-Tested
Activated Carbon Cloth
The inserts use a material that NASA has considered for spacecraft filters.

space-age insert for shoes
got its start when a graduate
student with smelly feet took off
her shoes and another tapped
into his aerospace experience to
solve the problem. The result
was Zorpads, shoe inserts that
use an extremely porous activated carbon cloth to absorb odor.
The inserts also work in gym
bags, trash cans, and other foulsmelling places.
Activated carbons are used in
all crewed spacecraft to condition the atmosphere for breath- To keep the air in the space station clean and safe for
ing and for odor control; for astronauts, NASA needs efficient methods of scrubbing
example, in toilet filters. Space- carbon dioxide and other harmful gases out of the
spacecraft's atmosphere. These " scrubbers " have been
craft cabins are relatively small, tested both in space and on the ground. (Credit:
enclosed spaces with equipment NASA/Anne McClain)
and people releasing a host of
contaminants that must be mitigated.
performed the cloths and became
Activated carbons are often part of stanNASA's choice for use aboard the ISS.
dard filtration systems, both on Earth
But the cloth Zorpads would use was
and in space. In most of its applications,
still shown to be extremely absorbent,
NASA uses granular activated carbons,
making it ideal in other situations
usually made from coconut shells
including as dressing for wounds. And
brought to very high temperatures withnow feet, too.
out oxygen to create a char - a process
Before attending Harvard Business
known as pyrolysis.
School, where he and four other classIn 2015, NASA compared a few difmates developed Zorpads as part of an
ferent cloths to several granular activatassignment, Taylor Wiegele had worked
ed carbon formulations as part of rewith activated carbons during stints at
search into removing contaminants
the water-purifying company Brita and
called siloxanes from the International
at SpaceX, where he consulted with
Space Station (ISS). Used in plastics,
NASA engineers on spacecraft atmoslike printed circuit boards, siloxanes
phere purification. " I came across a
are released into the atmosphere
number of really interesting materials
through offgassing.
and this one kept staying in my mind, "
In filtration systems, activated carbon
Wiegele said.
cloth can allow atmosphere to pass
" Later, when I started to develop the
more easily at high flow rates than
shoe insert, I realized this was the perpacked granular carbon. The NASA
fect material for that application, " he
team wanted to know if multiple layers
said. " NASA had done a lot of testing on
of activated carbon cloth, one on top of
it and those results helped us identify it
another, could absorb and filter siloxas the right material from the outset. "
anes as well as granular carbon without
To the business school study group's
causing more flow resistance. For that
surprise, the project won accolades.
application, the granular carbon outWiegele and one of the classmates,
56

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ToC

The makers of Zorpads shoe inserts used
NASA's research into activated carbon cloth to
determine that its filtering properties were
what they were looking for and began developing their odor-eliminating product around it.
(Credit: Zorpads)

Sierra Smith, incorporated the company in New York in 2016 and went on to
win a $150,000 investment on " Shark
Tank, " the business reality TV show
where entrepreneurs pitch their ideas
to investors.
The activated carbon cloth that
Zorpads uses is unique in that it is made
from a viscose rayon material derived
from wood pulp. Unlike some activated
carbon cloths, which are created by
applying carbon to a non-carbon cloth,
this material is 100% carbon.
Wiegele and Smith currently both
hold full-time jobs elsewhere but they
still promote and improve on Zorpads
as they can. They have developed more
effective adhesion to keep the inserts in
shoes, for instance, and determined better recommendations for where to place
the patches in different types of shoes.
Visit https://spinoff.nasa.gov/carboncloth-shoe-insert.
Tech Briefs, April 2021

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Tech Briefs Magazine - April 2021

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