Putting a soda bottle or takeout container into the recycling bin is far from a guarantee it will be turned into something new. Scientists at Rice University are trying to address this problem by making the process profitable. The amount of plastic waste produced globally has doubled over the past two decades. Furthermore, plastic production is expected to triple again by 2050 with most of it ending up in landfills, incinerated or otherwise mismanaged, according to the OECD.
Some estimates suggest that only 5% or less is actually being recycled. Waste plastic is rarely recycled because it costs a lot of money to do all the washing, sorting and melting down of the plastics to turn it into a material that can be used by a factory. But maybe that will change thank to nano-tech genius James Tour whose team is using their “flash Joule heating technique” to turn plastic into valuable carbon nanotubes and hybrid nanomaterials. Already, they’ve been able to make a hybrid carbon nanomaterial that outperformed both graphene and commercially available carbon nanotubes.
Graphene, carbon nanotubes and other carbon-based nanomaterials are generally strong and chemically robust, have low density and lots of surface area, and possess conductivity and broadband electromagnetic absorption abilities. This makes them useful in a variety of industrial, medical and electronics applications such as composites, coatings, sensors, electrochemical energy storage and more. What was really interesting about these results that they were able to make these carbon nanotubes with bits of graphene attached on the ends.
You can think of the structure of this new hybrid nanomaterial as similar to bean sprouts or lollipops. These are normally really hard to make, and the fact that the Rice team was able to make them out of waste plastic is really special. The plastic, which does not need to be sorted or washed as in traditional recycling, is “flashed” at temperatures about 5,120 degrees Fahrenheit. Beforehand, the material is ground into small, confetti-sized pieces, adding a bit of iron plus small amount of a charcoal for conductivity.
The concept of upcycling or turning low-value waste materials into something with a higher monetary or use value could be a real game-changer for the environment. If we can turn waste plastic into something more valuable, then people can make money off of being responsible in how they deal with discarded plastics.” A life cycle analysis of the production process revealed that flash Joule heating was considerably more energy-efficient and environmentally friendly than existing nanotube production processes. Compared to commercial methods for carbon nanotube production that are being used right now, this technique uses about 90% less energy and generates 90%-94% less carbon dioxide.