Most of the 150 million tons of plastics produced around the world every year end up in landfills, the oceans and elsewhere. Less than 9 percent of plastics are recycled in the United States, rising to about 30 percent in Europe.
That’s a $176 billion problem, the potential energy savings scientists say could be achieved from recycling all global plastic solid waste. But new approaches can increase the amount of plastic waste that can be successfully recycled, researchers from the University of Houston and IBM report in a perspective published this week in Science.
That means developing new plastics that are more easily recycled, along with finding ways to more efficiently recycle existing plastics. These approaches can range from methods to recycle different types of plastics together in one waste stream, avoiding a costly and time-consuming sorting process, as well as methods to break down plastics in a more energy-efficient manner.
“Recent research points the way toward chemical recycling methods with lower energy requirements, compatibilization of mixed plastic wastes to avoid the need for sorting, and expanding recycling technologies to traditionally nonrecyclable polymers,” wrote the article authors, Megan L. Robertson, associate professor of chemical and biomolecular engineering at UH, and Jeannette M. Garcia, a polymer chemist at the IBM Almaden Research Center.
Improving methods to recycle existing plastic materials is a key priority. “New materials enter the market slowly, and thus the biggest impact is in developing more efficient methods to recycle the plastics that are produced in large quantities today,” said Robertson. “One the other hand, research advances can pave the way for more easily recyclable materials for the future.” One example is the category of polymers known as thermosets, which can’t be melted down for repurposing, preventing their recycling with traditional methods.
Robertson’s lab develops biorenewable components for thermosets, replacing hydrocarbon-based polymers with those made from vegetable oils or other plant-based materials. That could lead to new end-of-life options such as composting or chemical recycling for these materials, a huge leap forward.
The perspective is part of a series published by Science to explore issues related to the environmental impact of polymers, including their source (petroleum vs. biosources), advances in recycling and biodegradable polymers.
Robertson and Garcia note three key issues:
- Plastics must be sorted for recycling, which adds effort and expense. Plastics, or polymers, are comprised of large molecules, so most don’t mix when heated, similar to the interaction between oil and water. Research is focused on finding substances that can facilitate the mixing of different types of plastics, known as compatibilizers, allowing them to be recycled together. Finding a compatibilizer that works for all polymers would be ideal, but Robertson said current technology requires a tailored approach for each plastic mixture.
- Chemical recycling involves using a catalyst to break down plastics to produce lower-molecular-weight products, a process the researchers say has been hindered by high energy costs. Work to develop more efficient catalysts is underway.
- The majority of plastics currently recycled are composed of polyethylene terephthalate (PET), which is the component used in most water bottles, and polyethylene, the most highly produced plastic. Expanding recycling technologies to other plastics beyond PET and polyethylene is an ongoing area of research. Even more challenging is developing methods for recycling polymers that can’t be processed through melting at elevated temperatures, such as thermosets and elastomers (rubber materials).
With any potential solution, the researchers say it is critical that a material’s performance isn’t impacted in order to make it easier to recycle. Subjecting plastics to many use and recycling cycles without loss of performance is an open challenge for researchers.
“Enhancing plastics recycling beyond the current level has many potential societal advantages, such as reducing greenhouse gas emissions, avoiding waste buildup in the environment, decreasing the dependence on finite petroleum resources for its production, and recovering the economic value of plastic solid waste,” the researchers wrote.
That has begun, they say, pointing to start-up companies that have scaled up chemical recycling methods for polystyrene waste or developed sorting processes to separate materials into pure feedstocks.
That and other research, they wrote, “raise hope that before long, recycling rates for plastics will be much higher than today.”
The Latest on: Plastic solid waste
Plastic threat no small matter on Galapagos
on March 25, 2019 at 2:39 pm
Yet while those objects may appear solid to the naked eye ... has tightened its rules regarding plastic use in recent years. Most of the plastic waste washing up on shores are bottles of Peruvian, ... […]
Plastic microparticles threaten unique Galapagos fauna
on March 25, 2019 at 1:37 pm
Tons of plastic waste wash up on the shores of the Galapagos islands where ... Yet while those objects may appear solid to the naked eye, when battered against rocks or by the force of waves, ... […]
China seizes 11.4 tonnes of adult diapers imported from US in crackdown on foreign waste
on March 25, 2019 at 9:56 am
But as part of efforts to clean up the environment, Beijing banned the import of 24 types of solid waste – including plastic, paper and textiles – from January 2018. It has since blocked another 16 ... […]
Urban Transformations: In Pune, India, Waste Pickers Go from Trash to Treasure
on March 25, 2019 at 9:55 am
She’d join her mother in pulling plastic bottles, cans and cardboard from roadside ... Pune isn’t the only city that has struggled to contain its waste. Municipal solid waste went largely unmanaged in ... […]
SANDALS FOUNDATION/UNEP ASSESS SOLID WASTE REDUCTION PROJECT
on March 25, 2019 at 8:42 am
The programme, which has been rolled out in some 40 locations in Whitehouse and Bluefields primarily, has provided over 200 bins for the separation of plastic bottles, compost and regular solid waste. ... […]
Rockland Lawmakers Pass Plastic Bag Ban
on March 25, 2019 at 6:40 am
"Plastic bags not only make Rockland County look terrible, they cause problems for our solid waste facility and pose a significant threat to the environment," Legislator Santulli said. "A simple ... […]
Roncesvalles resident trying to make 'a good deal for nature' by cutting plastic waste
on March 22, 2019 at 12:12 am
City holding consultations for single-use plastic Charlotte Ueta, with the City of Toronto's Solid Waste Management Services, says the city encourages neighbourhood-level action. "It's all about ... […]
Solid waste board eyes costlier contract to recycle glass
on March 20, 2019 at 9:56 pm
The Santa Fe Solid Waste Management Agency Joint Powers Board is considering ... the recycling of other materials like plastic and paper is increasing. The decrease in glass recycling since 2016 means ... […]
Utah city tables vote on plastic bag ban for 6 months
on March 20, 2019 at 1:10 pm
He says he thinks more will be accomplished if there is intermunicipality cooperation on reducing plastic. The Solid Waste Advisory Board will continue to develop the plastic reduction plan. […]
Logan City Council shelves vote to ban plastic bags
on March 19, 2019 at 8:13 pm
The decision to hold off on banning grocery stores and other retailers from distributing disposable plastic bags at the point of sale came after a vigorous debate. The ordinance would've gone into ... […]
via Google News and Bing News