Plastic pollution is among the world’s most pressing environmental issues, threatening drinking water, wildlife, food supplies and more. To address this multifaceted problem, University at Buffalo researchers are developing a novel set of tools that aim to reduce plastic waste and decrease the production of plastic. This includes a robotic system that relies on machine learning and other technologies to autonomously improve its ability to sort plastics, as well as environmentally responsible solvents and new chemistries that breakdown plastics to make them easier to reuse.
“Not only is this work critically important to our planet, it also contributes to the country’s advanced manufacturing capabilities. It will help meet both consumer demand for and corporate commitments to incorporating recycled plastics into commercial products,” says Paschalis Alexandridis, UB Distinguished Professor in the Department of Chemical and Biological Engineering, who is leading the multidisciplinary effort.
The project is supported by a four-year, $2 million grant the U.S. National Science Foundation (NSF) awarded UB this fall. It aims to improve the nation’s plastic recycling efforts, which have been muddled since China curtailed plastic waste importing in 2017 with its “National Sword” policy. It also includes public outreach strategies, such as recruiting students underrepresented in STEM (science, technology, engineering and math) fields.
UB Chemistry Professors Luis Velarde and Javid Rzayev are two of five co-investigators leading this research effort. The Velarde group will be leading efforts in identifying plastics using spectroscopic methods, while the Rzayev group will develop chemical methods to upcycle polyolefin-based plastics into value-added products.
The robotic system under development will combine novel sensor technology that can register the molecular signature of each piece of plastic, and machine learning that, on the basis of these molecular signatures, identifies in real-time the specific type of each piece of plastic.
By integrating this system with existing technologies, researchers aim to create an advanced mixed waste sorting process that also captures and reuses other materials often found in plastic recycling streams, such as contaminants and non-polymeric waste, that make recycling difficult and expensive.
In addition to the robotic system, the research team is investigating how to use environmentally responsible solvents to recover desirable plastics from mixed plastic streams. The solvents would separate the plastic from additives or impurities, and render it suitable for reuse in new products. The approach, known as chemical recycling, has low greenhouse gas emissions compared to other recycling methods.
The research team also will develop new chemical ways for the controlled breakdown of plastic molecules into valuable raw materials. For example, there is a group of plastics called polyolefins that are used in food packaging, toys and other products. Recovered and purified polyolefins could be upcycled to produce waxes used in adhesives, coatings and printing inks. They can also serve as building blocks for additive manufacturing technologies.