via Cornell University
Styrofoam egg cartons, hard plastic compact disc cases, red drinking cups and many other common products are composed of polystyrene, a type of plastic that makes up a third of landfill waste worldwide.
“In terms of plastic production and end-of-life waste streams, we are on the road to an unsustainable future,” said Erin Stache, assistant professor of chemistry and chemical biology in the College of Arts and Sciences.
But there’s good news: Stache has discovered a new path for polystyrene waste that includes being upcycled into benzoic acid, a chemical with wide commercial demand, through a mild process that uses light, an oxygen-rich environment and an abundant iron-based catalyst. The reaction can even take place in a sunny window.
The paper, “Chemical Upcycling of Commercial Polystyrene via Catalyst-Controlled Photooxidation” published March 23 in the Journal of the American Chemical Society. Doctoral candidate Sewon Oh is the lead author.
In line with her lab’s mission to tackle environmental concerns through interesting chemistry, the new process is mild, climate-friendly and scalable to commercial waste streams, Stache said. It efficiently produces benzoic acid, a product stocked in undergraduate and high school chemistry labs and also used in fragrances, food preservatives, and other ubiquitous products.
Moreover, the process is tolerant of additives inherent in a flow of consumer waste, including dirt, dyes and other types of plastics.
Polystyrene (PS) plastics vary widely in form, use and texture – from light, airy Styrofoam to hard CD cases, and many forms in between. All these products are similar in chemical composition, Stache said.
“The difference is in how they are processed,” she said. “Polystyrene foam, or Styrofoam, is filled with air, like a meringue, whereas a hard plastic CD case is solid polystyrene.”
At the molecular level, polymers (plastics) are composed of hundreds of small molecules called monomers assembled into long molecular chains through complicated processes, Stache said. Breaking down a polymer can be similarly intricate.
The researchers found that optimized conditions require a PS sample in acetone exposed to LED light in an oxygen-rich environment, using an iron chloride catalyst for 20 hours. In the optimized process, PS broke down to 23% benzoic acid. Other products included smaller plastic molecules that can be repurposed in other ways.
Last summer, Stache’s lab ran some degradation experiments in a sunny window; in a place with strong year-round sunlight, the reaction could be done outdoors.
“The advantage of using light is you can get exquisite control over the chemical process based on some of the catalysts we’ve developed to harness the white light. If we can use sunlight to drive the process, that’s a win-win,” Stache said, noting that many existing polymer recycling require heating a polymer for melting and processing, which usually requires fossil fuel.
To test the tolerance of the process to other materials mixed with the PS plastic, the researchers used several products, ranging from packaging materials to coffee cup lids.
They found that three items – a white coffee cup lid, Styrofoam and a clear lid – degraded efficiently. A black coffee cup lid degraded less efficiently, possibly because the black dyes inhibit light penetration, Stache said.
“These results signify that our system could efficiently break down commercial samples of PS, even with additional composite and insoluble material,” she said.
To demonstrate scalability and potential commercial application, the researchers created a setup with two syringe pumps and two LED lamps in a 3D-printed photoreactor. The efficiency of the breakdown process at the large scale was similar to that in small batches.
“If we can make the process even more efficient, we can think about how to commercialize it and use it to address waste streams,” Stache said.
Original Article: Light, oxygen turn waste plastics into useful benzoic acid
More from: Cornell University
The Latest Updates from Bing News & Google News
Go deeper with Bing News on:
Polystyrene waste
- A Styrofoam Ban Is Now In Effect In The City Of LA, But How Much Bite Would It Really Have?
No more Styrofoam container for your Chinese takeout or that Diet Coke you ordered — at least not in Los Angeles.
- With recent grant, Avon to become first Colorado municipality to offer Styrofoam recycling
The town of Avon is soon to become the first municipality in Colorado to implement a Styrofoam recycling program. On March 19, Avon sustainability staff received notice that the town’s application for ...
- Texas A&M University-Corpus Christi students tackle food waste for Earth Day
The Texas A&M University-Corpus Christi dining hall doesn't use Styrofoam or plastic bags ... the Islander Green Team had its eye on another sustainability goal — food waste. The student group, which ...
- San Diego's Ban on Single-Use Plastics and Polystyrene Shapes Eco-Friendly Future
San Diego marks one year since its ban on single-use plastics and polystyrene, positively impacting local businesses and the environment.
- Largest recycling collection event held in Ingham County
The event allowed people to dispose of difficult-to-recycle items such as electronics, dehumidifiers, scrap metal, and Styrofoam.
Go deeper with Google Headlines on:
Polystyrene waste
[google_news title=”” keyword=”polystyrene waste” num_posts=”5″ blurb_length=”0″ show_thumb=”left”]
Go deeper with Bing News on:
Upcycling polystyrene waste
- Who needs extra credit? Our 2024 recycling report card
Some products that have suffered from super-low recycling rates — bags, film, polystyrene, PVC — had big setbacks in 2023 and early 2024. I'm seeing progress in polypropylene and thermoformed PET, but ...
- What Those Plastic Recycling Numbers and Symbols Really Mean
Recycling can be confusing enough as it is. To help, here's what those little numbers in recycling symbols actually mean.
- How a coffee grinder and some old tyres led to the creation of sulphur-free light oil
Using a coffee grinder, a freezer and a furnace, researchers have discovered a chemical synergy between scrap tyres and polystyrene can be harnessed to create sulphur-free, light oil.
- Coffee grinder, old tires spur creation of sulfur-free oil
Using a coffee grinder, a freezer and a furnace, researchers have discovered a chemical synergy between scrap tires and polystyrene can be harnessed to create sulfur-free, light oil.
- Is Styrofoam Recyclable? Here’s What Experts Have to Say
Learn more about Styrofoam recycling and what recycling or upcycling options you have The post Is Styrofoam Recyclable? Here’s What Experts Have to Say appeared first on Reader's Digest.
Go deeper with Google Headlines on:
Upcycling polystyrene waste
[google_news title=”” keyword=”upcycling polystyrene waste” num_posts=”5″ blurb_length=”0″ show_thumb=”left”]