Page 65 - Plastics News January 2023

TECHNOLOGY

Such charcoal captures carbon and activated with potassium hydroxide Peter Nguyen is a co-author and Ab-
could potentially be added to soil was able to absorb 98% of the pollut- dul-Aziz is the corresponding author.
to improve soil water retention ant vanillin from test water samples. “It could be a very useful biochar
and aeration of farmlands. It could In the follow-up study, Abdul-Aziz because it is a very high surface area
also fertilize the soil as it naturally and her colleagues wanted to know material,” Abdul-Aziz said. “So, if
breaks down. Abdul-Aziz, how- if activated charcoal made from a we just stop at the char and not
ever, cautioned that more work combination of corn stover and plas- make it in that turn into activated
needs to be done to substantiate tic also could be an effective wa- carbon, I think there are a lot of
the utility of such char in agriculture. ter treatment medium. If so, plastic useful ways that we can utilize it.”
The plastic-to-char process was de- waste could be repurposed to clean Plastic is essentially a solid form of
veloped at UC Riverside’s Marlan up water pollution. But the activat- petroleum that accumulates in the en-
and Rosemary Bourns College of En- ed charcoal made from the mix ab- vironment, where it pollutes, entan-
gineering. It involved mixing one of sorbed only about 45% of vanillin in gles, and chokes and kills fish, birds,
two common types of plastic with test water samples – making it inef- and other animals that inadvertently
corn waste — the leftover stalks, fective for water cleanups, she said. ingest it. Plastics also break down into
leaves, husks, and cobs — collec- The char and activated carbon mak- micro particles that can get into our
tively known as corn stover. The mix ing process. “We theorize that bodies and damage cells or induce
was then cooked with highly com- there could be still some residual inflammatory and immune reactions.
pressed hot water, a process known plastic on the surface of the materi-
as hydrothermal carbonization. als, which is preventing the absorp- Unfortunately, it costs more to re-
cycle used plastic than it costs to
The highly porous char was pro- tion of some of these (vanillin) mol- make new plastic from petroleum.
duced using polystyrene, the ecules on the surface,” she said.
plastic used for Styrofoam Still, the ability to make highly porous Abdul-Aziz’s laboratory takes a differ-
ent approach to recycling. It is devot-
packaging, and polyethylene tereph- charcoal by combining plastic and ed to putting pernicious waste prod-
thalate, or PET, the material com- plant biomass waste is an important ucts such as plastic and plant biomass
monly used to make water and soda discovery, as detailed in the paper, waste back into the economy by upcy-
bottles, among many other products. “Synergistic and Antagonistic Effects of cling them into valuable commodities.
The study followed an earlier suc- the Co-Pyrolysis of Plastics and Corn “I feel like we have more of an agnos-
cessful effort to use corn stover Stover to Produce Char and Activated tic approach to plastic recycling when
alone to make activated charcoal Carbon,” published in the journal ACS you can throw it in (with biomass) and
used to filter pollutants from drink- Omega. The lead author is Mark Gale, use the char to better the soil,” she
ing water. In the earlier study, char- a former UCR doctoral student who said. “That's what we're thinking.”
coal made from corn stover alone is now a lecturer at Harvey Mudd
College. UCR undergraduate student

January 2023 PLASTICS NEWS 65