Grocery bags, used face masks, and food wrappers contain plenty of potentially useful raw materials. However, in the past, it has proven to be much more economical to keep manufacturing more of these single-use plastics than to recover and recycle them.
Now, an international team of researchers guided by the Department of Energy’s Pacific Northwest National Laboratory has cracked the code that stymied earlier attempts to break down these persistent plastics. The team has published their findings in the recent issue of the journal Science.
Low Temperature and Reaction Control
Typically, the process or recycling plastics has required the tough and stable bonds that also make them so persistent in the environment to be ‘cracked’ or split apart. This cracking step necessitates high temperatures, making it costly and energy demanding.
The novelty here is combining the cracking step with a second reaction step that immediately completes the conversion to a liquid gasoline-like fuel without unwanted byproducts.
The second reaction step makes use of alkylation catalysts. These catalysts offer a chemical reaction presently utilized by the petroleum sector to enhance the octane rating of gasoline.
Crucially in the current study, the alkylation reaction immediately follows the cracking step in a single reaction vessel near room temperature (70 °C/158 °F).
In their study, the research team, co-guided by researchers from the Technical University of Munich (TUM), Germany, highlighted separate and recent developments by the petroleum sector to commercialize the second step of the process stated here for crude oil processing.
In their research, the team notes a limitation in their results. The process is effective for low-density polyethylene products (LDPE, plastic resin code #4), such as squeezable bottles and plastic films, and polypropylene products (PP, plastic resin code #5) that are not normally collected in curb-side recycling programs.
High-density polyethylene (HPDE, plastic resin code #2) would necessitate a pretreatment to enable the catalyst access to the bonds it has to disintegrate.
Seeing Waste Plastic as Future Fuel and New Products
Petroleum-based plastic waste is an unexploited resource that can act as the starting material for beneficial durable materials as well as for fuels. Over half of the 360 million tons of plastics generated worldwide annually are the plastics explored in this study.
Yet, looking at a mountain of plastic and seeing its true value requires an innovator’s mindset, a chemist’s ingenuity, and a realist’s understanding of the economics involved. These researchers are attempting to alter the dynamic by applying their knowledge in efficiently breaking chemical bonds.
Polypeth Ekspor Indonesia is a supplier and export recycled plastic pellets (PET, HDPE, LDPE, PP & HIPS) based in Indonesia. We work with plastic recycling manufacturers with years of experience to provide and ensure high quality & the safety of our recycled plastic pellets. Together we reduce the use of virgin plastic resin and reduce the waste of virgin plastic pollution.
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