This is a problem many of us can relate to, is the plastic recyclable and where do I put it for recycling? I have two stories about solutions to these recycling issues.
Northwestern University
A September 2, 2025 Northwestern University news release (also on EurekAlert) by Amanda Morris announces a new catalyst for plastic recycling, Note: Links have been removed,
The future of plastic recycling may soon get much less complicated, frustrating and tedious.
In a new study, Northwestern University chemists have introduced a new plastic upcycling process that can drastically reduce — or perhaps even fully bypass — the laborious chore of pre-sorting mixed plastic waste.
The process harnesses a new, inexpensive nickel-based catalyst that selectively breaks down polyolefin plastics consisting of polyethylenes and polypropylenes — the single-use kind that dominates nearly two-thirds of global plastic consumption. This means industrial users could apply the catalyst to large volumes of unsorted polyolefin waste.
When the catalyst breaks down polyolefins, the low-value solid plastics transform into liquid oils and waxes, which can be upcycled into higher-value products, including lubricants, fuels and candles. Not only can it be used multiple times, but the new catalyst can also break down plastics contaminated with polyvinyl chloride (PVC), a toxic polymer that notoriously makes plastics “unrecyclable.”
The study will be published on Tuesday (Sept. 2 [2025]) in the journal Nature Chemistry.
“One of the biggest hurdles in plastic recycling has always been the necessity of meticulously sorting plastic waste by type,” said Northwestern’s Tobin Marks, the study’s senior author. “Our new catalyst could bypass this costly and labor-intensive step for common polyolefin plastics, making recycling more efficient, practical and economically viable than current strategies.”
“When people think of plastic, they likely are thinking about polyolefins,” said Northwestern’s Yosi Kratish, a co-corresponding author on the paper. “Basically, almost everything in your refrigerator is polyolefin based — squeeze bottles for condiments and salad dressings, milk jugs, plastic wrap, trash bags, disposable utensils, juice cartons and much more. These plastics have a very short lifetime, so they are mostly single-use. If we don’t have an efficient way to recycle them, then they end up in landfills and in the environment, where they linger for decades before degrading into harmful microplastics.”
A world-renowned catalysis expert, Marks is the Vladimir N. Ipatieff Professor of Catalytic Chemistry at Northwestern’s Weinberg College of Arts and Sciences and a professor of chemical and biological engineering at Northwestern’s McCormick School of Engineering. He is also a faculty affiliate at the Paula M. Trienens Institute for Sustainability and Energy. Kratish is a research assistant professor in Marks’ group, and an affiliated faculty member at the Trienens Institute. Qingheng Lai, a research associate in Marks’ group, is the study’s first author. Marks, Kratish and Lai co-led the study with Jeffrey Miller, a professor of chemical engineering at Purdue University; Michael Wasielewski, Clare Hamilton Hall Professor of Chemistry at Weinberg; and Takeshi Kobayashi a research scientist at Ames National Laboratory.
The polyolefin predicament
From yogurt cups and snack wrappers to shampoo bottles and medical masks, most people interact with polyolefin plastics multiple times throughout the day. Because of its versatility, polyolefins are the most used plastic in the world. By some estimates, industry produces more than 220 million tons of polyolefin products globally each year. Yet, according to a 2023 report in the journal Nature, recycling rates for polyolefin plastics are alarmingly low, ranging from less than 1% to 10% worldwide.
The main reason for this disappointing recycling rate is polyolefin’s sturdy, stubborn composition. It contains small molecules linked together with carbon-carbon bonds, which are famously difficult to break.
“When we design catalysts, we target weak spots,” Kratish said. “But polyolefins don’t have any weak links. Every bond is incredibly strong and chemically unreactive.”
Problems with current processes
Currently, only a few, less-than-ideal processes exist that can recycle polyolefin. It can be shredded into flakes, which are then melted and downcycled to form low-quality plastic pellets. But because different types of plastics have different properties and melting points, the process requires workers to scrupulously separate various types of plastics. Even small amounts of other plastics, food residue or non-plastic materials can compromise an entire batch. And those compromised batches go straight into the landfill.
Another option involves heating plastics to incredibly high temperatures, reaching 400 to 700 degrees Celsius. Although this process degrades polyolefin plastics into a useful mixture of gases and liquids, it’s extremely energy intensive.
“Everything can be burned, of course,” Kratish said. “If you apply enough energy, you can convert anything to carbon dioxide and water. But we wanted to find an elegant way to add the minimum amount of energy to derive the maximum value product.”
Precision engineering
To uncover that elegant solution, Marks, Kratish and their team looked to hydrogenolysis, a process that uses hydrogen gas and a catalyst to break down polyolefin plastics into smaller, useful hydrocarbons. While hydrogenolysis approaches already exist, they typically require extremely high temperatures and expensive catalysts made from noble metals like platinum and palladium.
“The polyolefin production scale is huge, but the global noble metal reserves are very limited,” Lai said. “We cannot use the entire metal supply for chemistry. And, even if we did, there still would not be enough to address the plastic problem. That’s why we’re interested in Earth-abundant metals.”
For its polyolefin recycling catalyst, the Northwestern team pinpointed cationic nickel, which is synthesized from an abundant, inexpensive and commercially available nickel compound. While other nickel nanoparticle-based catalysts have multiple reaction sites, the team designed a single-site molecular catalyst.
The single-site design enables the catalyst to act like a highly specialized scalpel — preferentially cutting carbon-carbon bonds — rather than a less controlled blunt instrument that indiscriminately breaks down the plastic’s entire structure. As a result, the catalyst allows for the selective breakdown of branched polyolefins (such as isotactic polypropylene) when they are mixed with unbranched polyolefins — effectively separating them chemically.
“Compared to other nickel-based catalysts, our process uses a single-site catalyst that operates at a temperature 100 degrees lower and at half the hydrogen gas pressure,” Kratish said. “We also use 10 times less catalyst loading, and our activity is 10 times greater. So, we are winning across all categories.”
Accelerated by contamination
With its single, precisely defined and isolated active site, the nickel-based catalyst possesses unprecedented activity and stability. The catalyst is so thermally and chemically stable, in fact, that it maintains control even when exposed to contaminants like PVC. Used in pipes, flooring and medical devices, PVC is visually similar to other types of plastics but significantly less stable upon heating. Upon decomposition, PVC releases hydrogen chloride gas, a highly corrosive byproduct that typically deactivates catalysts and disrupts the recycling process.
Amazingly, not only did Northwestern’s catalyst withstand PVC contamination, PVC actually accelerated its activity. Even when the total weight of the waste mixture is made up of 25% PVC, the scientists found their catalyst still worked with improved performance. This unexpected result suggests the team’s method might overcome one of the biggest hurdles in mixed plastic recycling — breaking down waste currently deemed “unrecyclable” due to PVC contamination. The catalyst also can be regenerated over multiple cycles through a simple treatment with inexpensive alkylaluminium.
“Adding PVC to a recycling mixture has always been forbidden,” Kratish said. “But apparently, it makes our process even better. That is crazy. It’s definitely not something anybody expected.”
Here’s a link to and a citation for the paper,
Stable single-site organonickel catalyst preferentially hydrogenolyses branched polyolefin C–C bonds by Qingheng Lai, Xinrui Zhang, Shan Jiang, Matthew D. Krzyaniak, Selim Alayoglu, Amol Agarwal, Yukun Liu, Wilson C. Edenfield, Takeshi Kobayashi, Yuyang Wang, Vinayak Dravid, Michael R. Wasielewski, Jeffery T. Miller, Yosi Kratish & Tobin J. Marks. Nature Chemistry volume 17, pages 1488–1496 (2025) DOI: https://doi.org/10.1038/s41557-025-01892-y Published: 02 September 2025 Version of record: 02 September 2025 Issue date: October 2025
This paper is behind a paywall.
Pink box
While British Columbia (Canada) can’t yer avail itself of the solution (that situation changed, in Vancouver anyway, as of February 2026) offered by Northwestern University (Chicago, US), there is the ‘pink box solution’ as described in a September 11, 2025 article by Chad Pawson for the Canadian Broadcasting Corporation’s (CBC) news online website,
The organization behind B.C.’s recycling system wants residents to do more to keep plastics from going to landfills or ending up as litter — as only 45 per cent of plastic packaging used by residents is recovered for recycling.
“There’s been a lot of hesitancy around recycling, but our model proves that you can have a system that responsibly manages and recycles these plastics,” said Sam Baker, executive director of Recycle B.C.
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In 2024, residents either put into their blue boxes or took to depots 31,362 tonnes of plastic packaging — from Ziploc bags to yogurt containers — of which 98 per cent was recycled, according to Recycle B.C.’s latest annual report.
B.C.’s not-for-profit system, introduced 10 years ago, was the first in North America to require producers to pay for the packaging and paper they create to be recycled, lifting the burden from local governments.
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In 2024, Recycle B.C. recovered 100 per cent of glass made by producers and used by residents, and 92 per cent of paper.
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The recovery of plastic bags and wrapping trails far behind the recovery of things like plastic containers, even though in 2022 Merlin Plastics figured out for Recycle B.C. how to turn flexible plastics into pellets for new products, rather than be burned as fuel.
Baker said there are several reasons for this, ranging from a lack of understanding of how B.C.’s system works and possible distrust in it, to confusion over how to sort items and ultimately the need to take some items to special depots.
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Recycle B.C.’s goal is to raise the recovery rate of all plastics to at least 50 per cent. One way to make gains will be to improve the recovery of flexible plastics, such as bags and wrappers.
Currently most residents need to collect and keep those items and then take them to one of 227 depots spread across the province or one of 53 London Drugs locations, which has recycling kiosks for items not accepted in curbside or multi-unit building pickup.
“London Drugs recognizes that we put a lot of material out into the market,” said Raman Johal, sustainability manager at the retail chain. “So we only feel right that we are responsible for taking some of that material back.”
But the corporate responsibility only works if residents are willing to make the effort to bring in the materials.
Recycle B.C. has a plan to overcome that barrier. In January it launched a pink box, to be used in communities alongside residents’ blue boxes.
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Aubrey Smethurst, a West Vancouver resident who works in marketing, describes the pink box as a “game changer.”
The mother of two says she has long cared about recycling and would go out of her way [emphasis mine] to make sure things like the plastic bags her family used got to depots.
Now she diverts them to her pink box, which gets picked up once a month from her home.
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I’m glad to learn of the pink boxes and hope to see one for my building in the near future. (That day arrived a few weeks ago) and I have a message for Mr. Baker,
Dear Mr. Baker,
I appreciate the ‘pink box’ option but could do without your scolding tone. Depots for recyclables in difficult to reach locations if you don’t have a car/truck. It’s especially difficult if the items in questions are awkwardly shaped.
As for the communication strategies used by organization, those could do with a bit or work. How did you get the message across about the change regarding soft plastics? Life is busy for most of us and putting out a notice on your website and a few notices at London Drugs stores and at your recycling depots is not enough. An article in a newspaper or on a media website is not enough.
Given how ‘media rich’ most people’s environments are, once or twice is not enough.
I suggest you abandon the scolding and simply work on getting the message out.
Sincerely
As much as was possible, Baker’s scolding was removed from Pawson’s article.
