Chemical Engineering April 2020 - 10

tainer. During discharge,
the heat from the PCM
is transferred, via heattransfer
fluid, to a sterling
engine that drives a
generator. The PCM is
based on recycled aluminum,
contains no rare
minerals, and suffers no
reduced capacity over
time, says the company.
The system is scalable
from 100 kW to 100 MW,
says the company.
TRI-METAL CATALYST
Last month, BASF SE
(Ludwigshafen, Germany;
www.basf.com) announced
that it had successfully
developed and
tested its Tri-Metal Catalyst
technology, which enables
partial substitution
of high-priced palladium
with lower-priced platinum
in light-duty gasoline
vehicles without compromising
emissions standards,
according to BASF.
Adoption of the Tri-Metal
Catalyst can reduce catalytic-converter
costs for
automakers and partially
rebalance market demand
for platinum group metals
(PGMs), thereby enhancing
PGM market sustainability,
the company adds.
The technology was developed
in collaboration
with, and support from,
Sibanye-Stillwater (www.
sibanyestillwater.com) and
Impala Platinum Ltd. (both
Johannesburg, South Aftrica;
www.implats.za).
SINGLE ATOM CATS
Single atom catalysts
(SACs) have attracted
significant attention because
they exhibit unique
catalytic performance due
to their ideal structure.
However, maintaining
atomically dispersed metal
under high temperature,
while achieving high catalytic
activity remains a formidable
challenge. Now,
the research group of professor
Hideo Hosono at
the Tokyo Institute of Technology
(TiTech; Japan;
www.titech.ac.jp) has de(Continues
on p. 11)
10
A desalination process that
pumps ions instead of water
R
esearchers from Indonesia's
Bogor Agricultural
University
(Bogor, Indonesia;
www.ipb.ac.id), the University
of Bath (U.K.; www.bath.
ac.uk), and the University of
Johannesburg (Johannesburg,
South Africa; www.
Accumulation
V
L
L
V
C+ = Cations
Film
Open
uj.ac.za), led by Budi Riza Putra, have developed
a low-cost, low-energy and low-maintenance,
solar-powered desalination system
that can be operated in mobile units. The system
could service a small number of households,
or homesteads in
remote locations
where freshwater is scarce.
The prototype desalination unit is a 3Dprinted
system with two internal chambers
designed to extract or accumulate salt (diagram).
When power is applied, salt cations
(positively
charged
ions) and salt
anions
(negatively charged ions) flow between chambers
through arrays of micro-holes in a thin,
negatively charged, membrane. The system
combines the membrane with an anionic resistor
that only allows the flow of negative ions
when power is applied. As a result of this oneway
flow, salt is pumped out of seawater. This
R
esearchers from the
Korea Advanced
Institute of Science
and Technology
(KAIST; Daejeon; www.
kaist.ac.kr) have developed
a three-dimensional (3D)
hierarchically porous nanostructured
catalyst that is
said to have a CO2-to-CO conversion rate
up to 3.96 times higher than that of conventional
nanoporous gold catalysts. Described
in the March 4 issue of the Proceedings of
the National Academy of Sciences, this new
catalyst is expected to help overcome the
existing mass-transport limitations that have
hampered existing electrocatalysts.
Gold is one of the most commonly used
catalysts in CO2 reduction reactions, but the
high cost and scarcity of Au pose obstacles
for mass commercial applications. The development
of nanostructures has been extensively
studied as a potential approach to improving
the selectivity for target products and
maximizing the number of active stable sites,
thus enhancing the energy efficiency. However,
the nanopores of previously reported
complex nanostructures were easily blocked
by gaseous CO bubbles during aqueous re3
µm
Depletion
Film
Closed
contrasts with the classical desalination process,
where water rather than salt is pumped
though a membrane.
The proof-of-concept prototype is currently
able to remove 50% of the salt from saltwater,
but to make seawater drinkable, the salt
content needs to be reduced by 90%. Another
benefit of the unit is that it also allows for the
opposite process - the up-concentration of
salt - minimizing waste. The separated salt
can be crystallized and then used either as a
food supplement or as a de-icer. Most other
desalination processes pump salt back into the
sea, which could upset the marine ecosystem.
" We need to find new and better porous materials
capable of pumping ions. Membrane thickness,
pore number and pore diameter must all
be optimized, " says Putra. " We hope to find materials
experts who can help us with this. "
This gold catalyst improves CO2 reduction
Professors Seokwoo Jeon and Jihun Oh, KAIST
actions. The CO bubbles
hindered mass transport of
the
reactants
through the
electrolyte, resulting in low
CO2 conversion rates.
The KAIST research
group, led by professors
Seokwoo Jeon and Jihun
Oh from the Dept. of Materials
Science and Engineering, designed
a 3D hierarchically porous Au nanostructure
with two different sizes of macropores
and nanopores (see scanning electron microscope
image). The team used proximityfield
nanopatterning (PnP) and electroplating
techniques that are effective for fabricating
the 3D well-ordered nanostructures.
The proposed nanostructure, composed of
interconnected macroporous channels 200
to 300 nm wide and 10 nm nanopores, induces
efficient mass transport through the interconnected
macroporous channels as well
as high selectivity by producing highly active
stable sites from numerous nanopores. As a
result, its electrodes show a high CO selectivity
of 85.8% at a low overpotential of 0.264 V
and efficient mass activity that is up to 3.96
times higher than that of de-alloyed nanoporous
Au electrodes, according to KAIST.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
APRIL 2020
http://www.ipb.ac.id http://www.bath http://www.ac.uk http://uj.ac.za http://www.basf.com http://kaist.ac.kr http://www.sibanyestillwater.com http://www.implats.za http://www.titech.ac.jp http://WWW.CHEMENGONLINE.COM
Chemical Engineering April 2020

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