Researchers first to demonstrate use of metal-organic frameworks to degrade plastics
What if the life cycle of the plastic bottle was circular? Where a used plastic bottle was returned to its original components, ready to be made into a new plastic bottle instead of possibly ending up in a landfill.
A Northwestern University research team is the first to demonstrate that a material called a metal-organic framework (MOF) is a stable and selective catalyst for breaking down polyester-based plastic into its component parts.
Only three things are needed: plastic, hydrogen and the catalyst. An important bonus is that one of the component parts the plastic is broken down into is terephthalic acid, a chemical used to produce plastic. With the Northwestern method, it isn’t necessary to go all the way back to oil and the expensive and energy-intensive production and separation of xylenes.
“We can do a lot better than starting from scratch when making plastic bottles,” said Omar Farha, a professor of chemistry in the Weinberg College of Arts and Sciences. He is the corresponding author of the study. “Our process is much cleaner.”
The work was published recently in the journal Angewandte Chemie.
The researchers chose a zirconium-basedMOF called UiO-66 because it is easy to make, scalable and inexpensive. Yufang Wu, the study’s first author and a visiting graduate student in Farha’s group, used the plastic that was most handy: the plastic water bottles her colleagues in the lab had discarded. She chopped them up, heated the plastic and applied the catalyst.
“The MOF performed even better than we anticipated,” Farha said. “We found the catalyst to be very selective and robust. Neither the color of the plastic bottle or the different plastic the bottle caps were made from affected the efficiency of the catalyst. And the method doesn’t require organic solvents, which is a plus.”
What are MOFs?
A class of nano-sized materials, MOFs have been widely investigated because of their highly ordered structures. Farha has studied MOFs for more than a decade and previously showed they can be used to destroy toxic nerve agents. In the current study, Farha said, MOFs act in much the same way — breaking an ester bond to degrade polyethylene terephthalate (PET). This plastic is one of the most popular consumer plastics worldwide.
“We’ve been using zirconium MOFs to degrade nerve agents for years,” Farha said. “The team then wondered if these MOFs could also degrade plastic even though the reactions and mechanism are different. That curiosity led to our recent findings.”
“This research helps to address long-standing challenges associated with plastic waste and opens up new areas and applications for MOFs,” Farha said.
MOFs are made of organic molecules and metal ions or clusters which self-assemble to form multidimensional, highly crystalline, porous frameworks. To picture the structure of a MOF, Farha said, envision a set of Tinkertoys in which the metal ions or clusters are the circular or square nodes and the organic molecules are the rods holding the nodes together.
In addition to being easy to make, scalable and inexpensive, another advantage of UiO-66 is that the MOF’s organic linker, terephthalic acid (TA), is what you get when breaking down plastic.
Structural characterization studies revealed that during the degradation process, UiO-66 undergoes an interesting transformation into another zirconium-based MOF called MIL-140A. This MOF also showed great catalytic activity toward PET degradation.
Original Article: Method efficiently breaks down plastic bottles into component parts
More from: Northwestern University
The Latest on: Degrading plastics
- A New Alternative To Single Use Plastic Water Bottleson December 6, 2022 at 6:15 am
Single use plastic water bottles are a major component of overall plastic waste with 50 billion purchased each year in the US. A company called Cove has just launched the first biobased, fully biodegr ...
- Plastics Recycling Misses the Point. Here's What We Have to Try Nexton December 6, 2022 at 5:00 am
There's no "silver bullet" for the plastics recycling problem. But here's what could help. Odds are, the next soda bottle you buy will be on this planet long after you're gone. That can be a jarring ...
- Engineering Plastics Are Becoming Sustainable, Attaining Circularityon December 4, 2022 at 1:55 pm
Renewable and recycled engineering plastics with mechanical performance as good as fossil-based polymers are now real. But they may represent only a drop in the ocean of global plastic waste.
- We need to stop using plastic bags | PennLive letterson December 3, 2022 at 8:51 am
Worldwide, 460 million tons of plastic are produced per year. It increases waste management expenses and accounts for 11.18% of plastic pollution. Plastic bags are the most common “single use plastic” ...
- The Other Sideon November 30, 2022 at 9:48 pm
In earth's battle with pollution caused by hard-to-degrade plastics, the tiny living things have demonstrated mighty power. Deep pockets, big appetite and a fierce focus on overseas expansion.
- Accelerating plastic degradation in the environment: Study researches heat resistance of enzymeson November 30, 2022 at 3:15 pm
Numerous plastics are principally biodegradable, but are only degraded very slowly in the open air, wastewater, or composting plants. Known enzymes with the ability to degrade plastics could solve ...
- Is there a way to respond to the plastics pandemic?on November 29, 2022 at 3:55 am
The conveniences plastics offer and that too at a low price have led to a throw-away culture. Today, single-use plastics account for 40 percent of the plastics produced yearly. Many of these products, ...
- Plastic pollution: Three problems that a global treaty could solveon November 28, 2022 at 2:24 pm
Plastic is one of the fastest growing materials and production is on course to double, to more than one billion tonnes a year, by 2050. With that, will come more pollution. This week, delegates from ...
- We Need a Global Treaty More Powerful Than the Plastics Industryon November 28, 2022 at 11:54 am
In the Philippines – one of the biggest recipients of plastic waste from all over the world – our communities disproportionately bear the brunt of environmental degradation caused by pollution with ...
- How micro(nano)plastics interact with human gut microbiotaon November 27, 2022 at 8:53 pm
Designed using elements by ©Canva via Canva.com (access date: May 2022, version used Canva 2.0) Gut microbiota is a major driving factor of MNP/plastic degradation, with insect larvae receiving ...
via Bing News
The Latest on: Degrading plastics
[google_news title=”” keyword=”degrading plastics” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
via Google News