Carbon recycling offers solution to plastic pollution

Carbon recycling offers solution to plastic pollution
by Clarence Oxford
Los Angeles CA (SPX) Nov 12, 2024

Plastics are an integral part of daily life, but the mounting plastic waste crisis presents significant environmental challenges. Researchers in Germany have introduced an innovative method for recycling polystyrene waste, detailed in *Angewandte Chemie*. This electrochemical process is powered by an iron catalyst, generates hydrogen as a byproduct, and can be sustained using solar energy.

Currently, less than 10% of global plastic is recycled, leaving a tremendous volume to accumulate in landfills and waterways. By 2025, global plastic waste is expected to surge to 40 billion tons. Polystyrene (PS), a common material in packaging and construction, comprises about 33% of landfill content but has a recycling rate of only 1%. In 2022, polystyrene production capacity reached 15.4 million tons, highlighting the urgent need for more effective recycling solutions. Methods that convert waste into valuable chemical components could contribute to a sustainable circular carbon economy.

Led by Lutz Ackermann, researchers at the Friedrich Wohler Research Institute for Sustainable Chemistry in Gottingen have developed an electrocatalytic method that efficiently breaks down polystyrene. This process yields monomeric benzoyl products, which can be used as raw materials for chemical manufacturing, along with shorter polymer chains.

The innovation relies on an iron-based catalyst, specifically an iron porphyrin complex resembling hemoglobin. Iron's advantages include its nontoxicity, affordability, and availability. During the process, the iron compound cycles through different oxidation states, facilitating the splitting of carbon-carbon bonds within the polymer backbone. The main products are benzoic acid and benzaldehyde, key components for synthesizing chemicals such as fragrances and preservatives. This robust method has been successfully tested on real-life polystyrene waste at a gram scale.

The electrocatalytic process can be powered entirely by solar electricity and includes hydrogen production as a beneficial side reaction. This makes the process not only efficient for recycling but also supportive of decentralized, sustainable hydrogen generation.

Research Report:Anodic Commodity Polymer Recycling: The Merger of Iron-Electrocatalysis with Scalable Hydrogen Evolution Reaction