Extracting valuable chemical building blocks from discarded polystyrene

Polystyrene, a commonly used polymer in plastic tableware and insulating materials, presents recycling challenges. A team of researchers from Virginia Tech in Blacksburg, U.S., has now introduced a thermochemical approach, known as “Degradation Upcycling” (Deg-Up), which allows for the recovery of valuable chemicals from polystyrene waste through a simple two-step process. This breakthrough method could revolutionize the recycling of insulating and packaging materials, contributing to the creation of a truly circular plastics economy.

The Deg-Up method developed by Guoliang Liu and his team involves breaking down polystyrene to obtain benzene as the main degradation product in the first step. In the second step, the benzene product is chemically modified in the same reactor, resulting in the production of various highly valuable aromatic chemicals. These chemicals find applications in industries such as cosmetics and pharmaceuticals, making them essential in the development of value-added products.

Previous methods for breaking down polystyrene into benzene were either costly, energy-intensive, or produced complex mixtures of products. However, Liu and his colleagues’ thermochemical method offers several advantages. The use of inexpensive aluminum chloride catalysts, combined with a moderate operating temperature of 80°C (ca. 180°F), makes the process more accessible and efficient. Additionally, the clever utilization of the solvent, benzene, ensures that only the amount recovered from the polymer is converted into the desired chemical, allowing for the recycling of unused solvent to process more polymer feed.

To demonstrate the effectiveness of their approach, the researchers dissolved various types of polystyrene waste, such as packing peanuts and plastic utensils, in benzene. The mixture was then heated in a reactor under air-free conditions, with aluminum chloride as the only reagent. The resulting liquid product, primarily composed of benzene, could be directly used to obtain the desired value-added chemicals with high yield and selectivity. For instance, the addition of specific reagents allowed for the production of important chemicals like acetophenone and benzophenone, which find applications in cosmetics, pharmaceuticals, and sunscreen products.

The ultimate goal of the Deg-Up method is to enable the recycling of large volumes of polystyrene waste into valuable chemicals for various industrial processes. Unlike mechanical recycling methods, which face limitations due to the low density of polystyrene insulating materials, Deg-Up offers robustness, contamination tolerance, and the potential for chemical upcycling on a large scale. This paves the way for a more sustainable approach to dealing with polystyrene waste and contributes to the development of a circular economy for plastics.

Denial of responsibility! SamacharCentrl is an automatic aggregator of Global media. In each content, the hyperlink to the primary source is specified. All trademarks belong to their rightful owners, and all materials to their authors. For any complaint, please reach us at – [email protected]. We will take necessary action within 24 hours.