【Frontiers in HaiChuan Chemical Technology】New method for recycling waste polyolefin plastics developed by the Institute of Physics and Chemistry, Chinese Academy of Sciences

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New method for recycling waste polyolefin plastics March 11, 2025 Recently, Ma Wangjing and his team from the Oil and Gas Research Center at the Institute of Physics and Chemistry, Chinese Academy of Sciences, in collaboration with universities such as Oxford University and Tsinghua University, have made progress in the use of microwave-driven catalysis for the recycling of waste polyolefin plastics. 　　The upgrading and recycling strategies for waste mixed plastics are of great significance, as they enable such waste to be directly converted into olefin monomers and other high-value chemicals. However, existing methods suffer from issues such as high energy consumption, the use of precious metals, high pressure, and low catalyst stability; in particular, direct upgrading and recycling of mixed waste plastics containing high levels of impurities is not yet possible. Therefore, how to efficiently utilize untreated mixed plastic waste in an economical and resource-efficient manner has become a key challenge in addressing global white pollution, attracting widespread attention from scientists. 　　Starting from the unique synergistic catalytic effect of atomic clusters and oxides, the research team designed and synthesized inexpensive zinc cluster/zinc oxide composite catalysts with strong microwave absorption and high catalytic activity using a simple and cost-effective in-situ synthesis method. An effective \"selective\" directional transfer of microwave energy to the catalyst was achieved in a low-power microwave field, enabling the depolymerization and upgrading of mixed waste plastics and agricultural films from landfills into olefin monomers and precursors for basic lubricants. Thanks to the excellent chemical bond activation capability of zinc atomic clusters, the enhanced electric field at the metal sites of these clusters, and the synergistic catalytic effect between zinc clusters and zinc oxide, the researchers were able to achieve \"selective\" depolymerization of mixed plastic waste under mild conditions of 280°C, atmospheric pressure, and low energy consumption; the catalytic performance obtained was superior to that of most noble metal catalysts. 　　This research and its industrial application hold the potential to promote the recycling of mixed plastic waste, as well as the sorted collection of urban waste, as well as the direct recycling of plastic waste from landfills and difficult-to-process composite materials, offering potential economic value and social benefits.