Scientists have created a way to convert plastic bags into carbon chips that could be used in batteries powering our smartphones and other devices. Plastic bag pollution has become a huge environmental problem, prompting some cities and countries to heavily tax or ban the sacks.
Many plastic bags are used only once and then disposed, ending up in landfills, oceans and elsewhere in the environment, where they can take hundreds of years to decompose. According to researchers from Purdue University in the US, polyethylene in plastic bags could be an inexpensive source of energy-storing carbon.
However, previous methods to upcycle polyethylene into pure carbon have been inefficient or required expensive, complex processes. The team wanted to develop a simpler yet efficient approach to convert plastic waste into useful carbon-containing materials.
The researchers immersed polyethylene plastic bags in sulphuric acid and sealed them inside a solvothermal reactor, which heated the sample to just below polyethylene’s melting temperature.
This treatment caused sulfonic acid groups to be added to the polyethylene carbon-carbon backbone so that the plastic could be heated to a much higher temperature without vapourising into hazardous gases.
Then, they removed the sulphonated polyethylene from the reactor and heated it in a furnace in an inert atmosphere to produce pure carbon. The team ground the carbon into a black powder and used it to make anodes for lithium-ion batteries. The resulting batteries performed comparably to commercial batteries.