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
- Planning for rescuing Karachi from the solid waste crisison September 15, 2019 at 9:19 am
Also, simultaneous to evolving of policy for ‘managing’ solid waste, it is important to ban/disincentivises certain items like plastic bags, cigarettes, crackers, among others– as have been done by ...
- Brightmark changing plastic recyclingon September 14, 2019 at 9:14 pm
ASHLEY — Steve Christman has seen numerous proposals from entrepreneurs over the years aimed at waste reduction and recycling in the nearly three decades he’s been the executive director of the ...
- Single-use plastic ban to be enforced in Anchorageon September 14, 2019 at 1:08 pm
Single-use plastic bags currently can be recycled at a few drop-off locations in Anchorage, said Suzanna Caldwell, spokeswoman for the city's Solid Waste Services. After Sunday, the Anchorage ...
- 'Waste' Examines The Global And Local Afterlife of Recyclableson September 13, 2019 at 3:13 pm
So that was seen as a big problem. But also, what happened to the rest of the waste, it's hard to tell. I mean, China incinerates a lot of plastic and other kinds of solid waste. They've got a big ...
- How this startup is using laser mapping to tackle marine wasteon September 13, 2019 at 2:01 am
More than 150 million metric tons of plastic have already accumulated in the world's ... in maritime ports by automatically and remotely calculating the volumes of solid waste held in a container. Its ...
- Anchorage’s plastic bag ban takes effect Sunday. Here’s what to expect.on September 12, 2019 at 5:20 pm
That’s hard to say, said Suzanna Caldwell, spokeswoman for the city’s Solid Waste Services. No one has studied plastic bags’ contribution to landfill waste specifically, but all non-recyclable ...
- Assessment of status of solid waste management in Asella town, Ethiopiaon September 11, 2019 at 5:33 pm
(Table 1). Variety of solid waste was reported to be generated from the households included in to the study. Accordingly; 328, 296 and 285 households’ heads have reported that they generated plastic, ...
- China's solid waste imports fall due to foreign garbage banon September 8, 2019 at 9:45 am
The country's solid waste imports reached 9.7 million tonnes during the January-August period, down 29 percent year on year, according to the General Administration of Customs. In August alone, ...
- CU Boulder Replaces Plastic Cups with Aluminum at Football Stadiumon September 6, 2019 at 7:45 am
The university aims to become plastic-free for single-use beverages in sports venues by 2020. It’s also looking to increase campus-wide municipal solid waste diversion from 51% in 2018 to 90% in 2025.
- Ban on single-use plastic not enough, waste management equally criticalon September 4, 2019 at 11:03 pm
with 40 per cent plastic waste being uncollected and 60 million tonnes of solid waste generated in one year. Companies have already started issuing statements about their move in this direction.
via Google News and Bing News