
The char and activated carbon making process.
Turning plastic waste into a valuable soil additive
University of California, Riverside, scientists have moved a step closer to finding a use for the hundreds of millions of tons of plastic waste produced every year that often winds up clogging streams and rivers and polluting our oceans.
In a recent study, Kandis Leslie Abdul-Aziz, a UCR assistant professor of chemical and environmental engineering, and her colleagues detailed a method to convert plastic waste into a highly porous form of charcoal or char that has a whopping surface area of about 400 square meters per gram of mass.
Such charcoal captures carbon and could potentially be added to soil to improve soil water retention and aeration of farmlands. It could also fertilize the soil as it naturally breaks down. Abdul-Aziz, however, cautioned that more work needs to be done to substantiate the utility of such char in agriculture.
The plastic-to-char process was developed at UC Riverside’s Marlan and Rosemary Bourns College of Engineering. It involved mixing one of two common types of plastic with corn waste — the leftover stalks, leaves, husks, and cobs — collectively known as corn stover. The mix was then cooked with highly compressed hot water, a process known as hydrothermal carbonization.
The highly porous char was produced using polystyrene, the plastic used for Styrofoam packaging, and polyethylene terephthalate, or PET, the material commonly used to make water and soda bottles, among many other products.
The study followed an earlier successful effort to use corn stover alone to make activated charcoal used to filter pollutants from drinking water. In the earlier study, charcoal made from corn stover alone activated with potassium hydroxide was able to absorb 98% of the pollutant vanillin from test water samples.
In the follow-up study, Abdul-Aziz and her colleagues wanted to know if activated charcoal made from a combination of corn stover and plastic also could be an effective water treatment medium. If so, plastic waste could be repurposed to clean up water pollution. But the activated charcoal made from the mix absorbed only about 45% of vanillin in test water samples – making it ineffective for water cleanups, she said.
“We theorize that there could be still some residual plastic on the surface of the materials, which is preventing the absorption of some of these (vanillin) molecules on the surface,” she said.
Still, the ability to make highly porous charcoal by combining plastic and plant biomass waste is an important discovery, as detailed in the paper, “Synergistic and Antagonistic Effects of the Co-Pyrolysis of Plastics and Corn Stover to Produce Char and Activated Carbon,” published in the journal ACS Omega. The lead author is Mark Gale, a former UCR doctoral student who is now a lecturer at Harvey Mudd College. UCR undergraduate student Peter Nguyen is a co-author and Abdul-Aziz is the corresponding author.
“It could be a very useful biochar because it is a very high surface area material,” Abdul-Aziz said. “So, if we just stop at the char and not make it in that turn into activated carbon, I think there are a lot of useful ways that we can utilize it.”
Plastic is essentially a solid form of petroleum that accumulates in the environment, where it pollutes, entangles, and chokes and kills fish, birds, and other animals that inadvertently ingest it. Plastics also break down into micro particles that can get into our bodies and damage cells or induce inflammatory and immune reactions.
Unfortunately, it costs more to recycle used plastic than it costs to make new plastic from petroleum.
Abdul-Aziz’s laboratory takes a different approach to recycling. It is devoted to putting pernicious waste products such as plastic and plant biomass waste back into the economy by upcycling them into valuable commodities.
“I feel like we have more of an agnostic approach to plastic recycling when you can throw it in (with biomass) and use the char to better the soil,” she said. “That’s what we’re thinking.”
Original Article: Turning plastic waste into a valuable soil additive
More from: University of California Riverside
The Latest Updates from Bing News
Go deeper with Bing News on:
Plastic-to-char process
- Layers Of Fear Preview - A Definitive Edition Created Through "Death By A Thousand Cuts"
The upcoming horror game is billed as the "crowning work of the Layers of Fear universe." GameSpot may get a commission from retail offers. As I paced the weathered lighthouse hallways, anxiously ...
- Plastics recycling must do better by consumers to succeed, professor says
A Virginia Tech professor believes consumers are being left out of the recycling process and have the ability to do more with the proper knowledge.
- What happens to a plastic bottle that’s recycled in Raleigh? Watch the journey.
When a plastic soda or water bottle is recycled in ... down and spun into yarn to make brand new items. Take a look at the process in the video above. Find all of our coverage on recycling in ...
- In Uttarakhand, point and shoot plastic
The Uttarakhand government has chosen the Char Dham yatra route that includes ... Visitors will scan a QR code on each plastic bottle and multi-layer plastic bag (of chips or biscuits) and pay ...
- New Conversion Method Turns Plastic Into Fuel
Researchers at Pacific Northwest National Laboratory have discovered a novel, low-temperature way to convert waste plastic into a gasoline-like fuel and raw materials ...
Go deeper with Bing News on:
Plastics upcycling
- Bisleri International’s new campaign showcases its resolve to upcycle used plastic
Bisleri International has unveiled its sustainability campaign - Bisleri Greener Promise. The campaign highlights the role of Bisleri as a responsible corporate committed towards water security, ...
- Plastics: PETG
You’d be hard-pressed to walk down nearly any aisle of a modern food store without coming across something made of plastic. From jars of peanut butter to bottles of soda, along with the trays ...
- New catalyst helps turn plastic waste into useful organosilane compounds
The result is a reaction that requires less demanding conditions—a greener method for upcycling waste. The paper is published in the Journal of the American Chemical Society. Recycling is a big part ...
- Face Off: Should Hong Kong ban single-use plastic tableware?
Each week, two readers debate a hot topic in a showdown that doesn’t necessarily reflect their personal viewpoints. This round, they discuss whether the city should ban one-off plastic utensils.
- Biden sets US goal to replace 90% of plastics with biomaterials
A new report from the White House calls for rapid advancements over the next 20 years in bio-based plastics as part of a bigger government biotech strategy.