Plastic waste is a huge problem in the world. Because of its durability, plastic waste accumulated in landfills and oceans tends to be trapped for centuries, causing a global environmental crisis. Even though we produce about 300 million tons of plastic waste each year, only 9% is recycled. But why are we only recycling so little? The reason is the current inefficiency and high cost of recycling plastic waste, resulting in a lack of incentives. Recently, researchers from Washington State University discovered a more efficient method that can drastically improve the efficiency of chemically recycling plastic waste.
Currently, there are three types of plastic waste recycling: mechanical recycling, incineration, and chemical recycling. Mechanical recycling is the most widely used recycling option, and it involves mechanically grinding or compounding plastic waste for re-use in similar products. However, this process will result in poorer plastic quality, and thus these recycled products are not widely used by industries. Incineration can convert plastic waste into heat and electricity, but the process may result in the emission of toxic pollutants such as acid gases and heavy metals. Therefore, the last option, chemical recycling, where plastics are converted to fuels, is considered to be the most promising plastic waste recycling process with the least adverse effects. However, the current technology of chemical recycling requires extremely high temperatures (over 300°C), which is expensive and inefficient.
In order to improve this, these researchers investigated the effects of using different metals as catalysts, which are materials that can speed up the conversion process, while also varying other process conditions such as temperature and pressure. They discovered that, using a combination of ruthenium metal and carbon as the catalyst, they can convert 90% of plastic waste into fuel in just one hour, at a lower temperature of 220°C. This condition is significantly more efficient and cost-effective than the current chemical recycling standard.
If we continue our current rate of only recycling 9% of plastic waste, our ocean will contain more plastic than fish by 2050. This new discovery may provide a promising and more incentivized approach for ramping up the recycling process of plastics in the near future. These researchers are now working on trying to scale up and commercialize this process, which will be very useful in the global goal of reducing plastic waste.
The first author of the study, Chuhua Jia, is a PhD student in the Department of Chemical Engineering at Washington State University.
Managing Correspondent: Wei Li
Press Article: Plastic waste can now be turned into jet fuel in one hour, The Academic Times.
Original Article:Deconstruction of high-density polyethylene into liquid hydrocarbon fuels and lubricants by hydrogenolysis over Ru catalyst, Chem Catalysis.