Tech Briefs Magazine - February 2022 - 39

Sustainable Technology
Cleaner Water Through Corn
Activated carbon made from corn stover filters 98 percent of a pollutant from water.
University of California, Riverside, CA
bout half the corn harvest -
stalks, leaves, husks, and cobs -
remains as waste after the kernels have
been stripped from the cobs. These
leftovers, known as corn stover, have
few commercial or industrial uses
aside from burning. Researchers developed
an energy-efficient way to put
corn stover back into the economy by
transforming it into activated carbon
for use in water treatment.
Activated carbon, also called activated
charcoal, is charred biological material
that has been treated to create millions
of microscopic pores that increase how
much the material can absorb. It has
many industrial uses, the most common
of which is for filtering pollutants out of
drinking water.
The researchers compared methods
for producing activated carbon from
charred corn stover and found that processing
the biomass with hot compressed
water - a process known as hydrothermal
carbonization - produced activated
carbon that absorbed 98 percent of the
water pollutant vanillin.
A
Corn
Stover
Direct Activation (KOH)
Wastewater
O
OH
KOH
HTC
Biochar
Vanillin
AC
O
SP
Clean Water
The method by which corn stover is turned to biochar, then to activated carbon for water filtration.
(Photo: Abdul-Aziz et. al., 2021)
Hydrothermal carbonization created a
biochar with higher surface area and
larger pores when compared to slow
pyrolysis - a process where corn stover is
charred at increasing temperatures over
a long period of time. When the
researchers filtered water into which
vanillin had been added through the
activated carbon, its combination of larger
surface area and bigger pores enabled
the carbon to absorb more vanillin.
Finding applications for resources
such as corn stover could help combat
climate change.
For more information, contact Holly Ober
at holly.ober@ucr.edu; 951-827-5893.
Chemistry Discovery Could Remove Micropollutants from
the Environment
This approach could result in developing chemical sensors that are sensitive at a very low
level to a specific chemical in the environment.
Army Research Laboratory, Research Triangle Park, NC, and Cornell University, Ithaca, NY
rmy-funded research identified a new
chemistry approach that could
remove micropollutants from the environment.
Micropollutants are biological or
chemical contaminants that make their
way into ground and surface waters in
trace quantities.
A
Using a pioneering imaging technique,
Cornell University researchers obtained a
high-resolution snapshot of how ligands
- molecules that bind to other molecules
or metals - interact with the surface of
nanoparticles. In doing so, they made an
unexpected discovery; by varying the conTech
Briefs, February 2022
Cov
centration of an individual ligand, they
could control the shape of the particle it
attached to. This approach could result in
developing chemical sensors that are sensitive
at a very low level to a specific chemical
in the environment.
The research studied interactions of ligands
and gained new understanding of
the strength, or affinity, of ligand adsorption
as well as how multiple ligands cooperate,
or don't, with each other. When the
molecule adsorbs on the surface of a
nanoscale material, it also protects the surface
and makes it more stable. This can be
www.techbriefs.com
ToC
utilized to control how nanoscale particles
grow and become their eventual shape.
Understanding how ligands interact
with the surface of nanoparticles has been
a challenge to study. Adsorbed ligands are
difficult to identify because there are other
molecules in the mix and nanoparticle
surfaces are uneven and multifaceted,
which means they require incredibly high
spatial resolution to be scrutinized.
A nanoparticle's size and surface structures,
or facets, are intrinsically tied to the
particle's potential applications. The larger
the particle, the more atoms fit inside it,
39

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Tech Briefs Magazine - February 2022

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