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Empty colored carbonated drink bottles. Plastic waste
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Urban Mining: Turning Urban Waste Into Valuable Products

Renowned synthetic chemist Jim Tour shows how we can turn discarded plastics into graphene, a product useful in industry

There’s a gold mine, so to speak, in the garbage but it takes a gifted chemist to develop processes that turn the trash to valuable industrial materials. At COSM 2021, James Tour talked about his team’s work in developing such processes:

The Nanotech Revolution: Our Zero-Waste Energy Future (November 11, 2021)

Dr. Jim Tour, Professor of Chemistry at Rice University, gives a riveting tour of how waste products can be converted to graphene, an extremely valuable material with a host of useful applications—from medical applications to new strong and lightweight materials to an energy source for zero CO2 emissions.

Tour and his team have developed methods for turning carbon waste into graphene, an allotrope of carbon that can be stacked to form graphite (best known as the “lead” in pencils).

The “flash” part is that, via a “flash treatment,” electrodes induce a high voltage and high current into a sample of carbon-rich waste. Ten milliseconds and 3,300 degrees Kelvin later, you’ve created a usable form of graphene. At $30-35 in electricity costs per ton, the process is highly economical.

And then what? “Where are you going to put 8 billion tons of carbon?” Tour asked. Well, “You could put 8 billion tons of graphene in cement and concrete.”

Casey Luskin, “Born-again plastic is planet-friendly” at Mind Matters News (November 12, 2021)

It’s called “urban mining.” And our cities are — properly managed — not garbage generators but rich mines for chemical compounds and elements:

Waste food filling up landfills is an additional source of greenhouse gases — not just of CO2 but also of the more potent gas, methane (CH4). On top of that, three hundred million tons of plastic are thrown into landfills and hundreds of millions of tires are discarded each year. All this waste is full of carbon — carbon which most people assume is useless or harmful. Thus, if Tour succeeds in pioneering the conversion and recycling of much of that carbon into graphene, it won’t end up in the atmosphere.

Urban mining promises not only environmental benefits but geopolitical ones as well. Everyone needs REEs to build computers. But during my geology PhD in South Africa, I often heard about how China is trying to corner the world market on REE mining. China knows what it is doing: Control the supply of REEs and you control the ability of people to build all kinds of tech.

Tour said we’re currently dependent on China for 95% of our REEs. But we’ve already pulled tons of REEs and other tech-necessary elements out of the ground and put them into technology — which we then discarded when the next better thing came on the market. His team has figured out how to recover REEs from that e-waste, and also from other forms of waste such as fly ash and bauxite residue. With efficient and economical flash techniques, one man’s trash could literally become another man’s next-generation computer.

Casey Luskin, “Born-again plastic is planet-friendly” at Mind Matters News (November 12, 2021)

Here’s Tour’s lab at work:


You may also wish to read: Manipulating molecules: Combining info + nano for better medicine. At COSM 2021, scientists like Jim Tour and entrepreneurs like Matt Scholz offer a window into how we are learning to manipulate the building blocks of life. Designed information is the basis of biology so if you want to fix medical problems at the root, designing better information is the way to go. (Casey Luskin)

and

Flash graphene: Born again plastic is planet-friendly. Chemist James Tour outlined a new approach to carbon waste at COSM 2021: Use electricity to turn it into graphene, to be recycled as new materials. “Urban mining” both recovers rare earth elements from discarded computers and reduces our vulnerability to shortages that could cripple technology.


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Urban Mining: Turning Urban Waste Into Valuable Products