An international team of scientists conducting basic research has discovered a way to use polyethylene waste (PE) as a raw material. They were able to convert it into a valuable chemical through a process called light-driven photocatalysis.
The University of Adelaide’s Professor Shizhang Qiao, Head of the Department of Nanotechnology in the School of Chemical Engineering and Director of the Center for Energy and Catalytic Materials, led the team and published the research results in an academic journal. scientific progress.
“We upcycled polyethylene plastic waste into ethylene and propionic acid. acid “High selectivity can be achieved by using atomically dispersed metal catalysts,” said Professor Qiao.
“We used an oxidatively coupled room-temperature photocatalytic method to convert waste into valuable products with high selectivity.As nearly 99% of the liquid product is propionic acid, the complexity associated with the product requiring separation problems are reduced. Renewable solar energy was used instead of industrial processes that consume fossil fuels and emit greenhouse gases. This waste-to-value strategy primarily focuses on plastic waste, water, solar It runs on four components, including a non-toxic photocatalyst that uses light, solar energy to accelerate the reaction. A typical photocatalyst is titanium dioxide with isolated palladium atoms on its surface.”
Tackling the issue of plastic waste
Most of the plastics currently used end up being thrown away and accumulating in landfills. PE is the most widely used plastic in the world. Everyday food packaging, shopping bags, reagent bottles, etc. are all made of PE. It also accounts for the largest proportion of all plastic waste and mainly ends up in landfills, posing a threat to the global environment and ecosystems.
“Plastic waste is an untapped resource that can be recycled and processed into new plastics and other products,” Professor Qiao said.
“Catalytic recycling of PE waste is still in the early stages of development and is difficult in practice due to side reactions resulting from the chemical inertness of the polymer and the structural complexity of the reacting molecules.”
Potential impact and future applications
Current chemical recycling of PE waste is carried out at high temperatures of over 400 degrees Celsius, producing complex product compositions.
Ethylene is an important chemical raw material that can be further processed into various industrial products and household items, while propionic acid is also in high demand due to its preservative and antibacterial properties.
The team’s efforts aim to address modern environmental and energy challenges and contribute to a circular economy. It will be useful for further scientific research, waste management and chemical manufacturing.
“Our basic research provides green and sustainable solutions that simultaneously reduce plastic pollution and produce valuable chemicals from waste for a circular economy,” said Professor Qiao. said.
“This will stimulate the rational design of high-performance photocatalysts for solar energy utilization and benefit the development of photovoltaic waste upcycling technologies.”
Reference: “Photocatalytic production of ethylene and propionic acid from plastic waste using titania-supported atomically dispersed Pd” seed” Shuai Zhang, Bingquan Xia, Yang Qu, Liqiang Jing, Mietek Jaroniec, Jingrun Ran, Shi-Zhang Qiao, December 8, 2023. scientific progress.
DOI: 10.1126/sciadv.adk2407