The ultimate solution to plastic pollution is to generate less of it. In the meantime, researchers are working on new ways to recycle it. One new promising area of research is under way at Purdue University. Last week, the school reported that a team of scientists at its Davidson School of Chemical Engineering has invented a system for converting plastic waste to liquid fuel and other products.
The new research provides a new pathway for both a bottom line and a sustainable business response to the plastic pollution crisis.
Companies have achieved some success with the plastic-to-plastic recycling model, in which old plastic is used to make new plastic items. However, the relatively narrow scope of that market leaves it open to disruption. That problem came to light last year, when China placed a ban on incoming trash for recycling.
Recycling plastic into liquid fuels and other new uses represents a significant step up from the conventional model. It spreads the recycled plastic supply chain out into the transportation fuel sector and other areas of application.
It is also a step up from the conventional approach to recycling plastic for fuel. Until now, the waste-to-energy operations typically involved incinerating plastic along with other trash to produce heat, and then converting that heat into electricity.
Converting plastic into liquid fuels is a more sophisticated approach, with the potential for a wider range of applications.
According to lead researcher Linda Wang, the Purdue team aims to incentivize plastic recycling by focusing on supply chain streams that add value, including “polymers, naphtha (a mixture of hydrocarbons), or clean fuels.”
Specifically, the research is focused on converting polyolefin. Polyolefin is a building block for plastics 2, 4 and 5, among other materials.
The ocean plastic pollution problem was Wang’s initial inspiration for the research project, but polyolefin covers much more ground. It is used for making fuel tanks and bottle caps as well as plastic bottles (#2), liquid containers, tubing and plastic wrap (#4), and various forms of piping, carpeting, roofing materials and auto parts (#5).
Polyolefin also factors into the nets and ropes used in fishing gear, which is a major source of ocean plastic pollution. By adding more value to the plastic recycling market, the Purdue innovation could stimulate efforts to harvest and recycle old fishing gear — or better yet, take more steps to prevent the loss of fishing gear.
Along with Wang, the new research is credited to an interdisciplinary team that includes the Purdue School of Engineering Technology, through its Fuel Laboratory of Renewable Energy of the School of Engineering Technology.
The team developed a two-step approach based on heating water past the boiling point. The first step of the process converts plastic into naphtha.
The rest is practically gravy, as described by the Purdue news team:
“Once the plastic is converted into naphtha, it can be used as a feedstock for other chemicals or further separated into specialty solvents or other products.”
According to Wang, the conversion rate of the new system could reach up to 90 percent, which indicates a promising pathway to commercialization.
In addition to the direct economic incentive, the system could attract investors who see value in creating a portfolio that addresses an existing problem — ocean plastic pollution — in addition to creating a sustainable supply chain.
The introduction to the team’s research paper, recently published in the journal Sustainable Chemistry & Engineering, emphasizes the benefits for companies and investors that value a solid sustainability profile:
“About five billion tons of plastic waste have accumulated in landfills and the natural environment over the past 50 years. Polypropylene [a common form of polyolefin] waste accounts for about 23 percent of the total plastic waste. Converting PP waste into useful products can reduce the accumulated waste and associated risks to the environment and human health.”
Aside from ocean plastic waste problem, the breakthrough could help solve some significant lifecycle issues in other areas.
One area that comes to minds is the plastic used in children’s toys and accessories, which can mean anything from palm-sized dolls to play sets and child-sized cars, play houses and furniture.
Most of these products have a severely limited lifespan, ranging from just a few months in the case of infants and toddlers to perhaps a few years for young children.
As with all plastic, the best solution is to use less. Absent any other incentive to change habits, though, a more efficient approach to recycling could provide businesses with incentive to reclaim more plastic for a broader span of uses.
Purdue is highlighting the new research as part of its “Giant Leaps” 150th anniversary celebration of global innovation.
It’s not all happy talk. In the sustainability field, for example, Purdue is also highlighting the here-and-now impacts of climate change, and discussing the effort it will take to scale up and accelerate climate solutions.
Climate change is forcing a structural change in the global economy. Businesses and investors who see opportunity in the sustainability field are the ones who will ride the next wave of economic expansion.
Image credit: Purdue University/stock photo
Tina writes frequently for TriplePundit and other websites, with a focus on military, government and corporate sustainability, clean tech research and emerging energy technologies. She is a former Deputy Director of Public Affairs of the New York City Department of Environmental Protection, and author of books and articles on recycling and other conservation themes. She is currently Deputy Director of Public Information for the County of Union, New Jersey. Views expressed here are her own and do not necessarily reflect agency policy.