Researchers at the University of Illinois in Chicago have developed a new approach that is capable of converting captured carbon almost entirely to ethylene, a key component of many industrial goods, such as plastics and detergents.
While converting carbon dioxide into ethylene is not new, previous processes have had conversion rates as low as 10% and needed substantial energy to separate the ethylene from the remaining carbon dioxide. The new process is the first to have a near-100% conversion rate, and if it is powered by renewably generated electricity, it will be carbon negative, as explained by team leader Meenesh Singh:
“It’s a net negative. For every 1 ton of ethylene produced, you’re taking 6 tons of CO2 from point sources that otherwise would be released to the atmosphere.”
The new approach passes an electric current through a cell separated by a membrane into halves, one half with a water-based solution, and carbon dioxide for the other half. Hydrogen atoms are drawn from the water to the carbon dioxide, where they form ethylene once combined.
ExxonMobil, the maker of Mobil grease and fluid products, has invested heavily in carbon capture, but the usual approach is to permanently store the captured carbon, such as in disused oil and gas fields. The new process could instead mean transforming this captured carbon into a useful industrial feedstock. The global production of ethylene is currently responsible for about 260 million tons of CO2 emissions, making it the third biggest cause of chemical-production emissions after ammonia and cement.