University of Michigan researchers treat wastewater while capturing CO2 and byproducts

In Michigan, a team of researchers from the University of Michigan is working on a new way to treat that wastewater while capturing CO₂ and creating useful products, like green fuels and chemicals. When biodiesel is made, fats from things like vegetable oil, animal fat, or used cooking grease are turned into fuel through a process called transesterification.

This process uses alcohol (usually methanol) and a catalyst to break fat molecules into two parts: fatty acid esters, which become biodiesel, and glycerol, a waste product. Glycerol ends up in the wastewater, and if left untreated, it can harm the environment by lowering oxygen in the water, which can kill fish and other wildlife.

Traditionally, treatment methods focus on removing the glycerol. But now, scientists are trying to recover valuable materials from the wastewater, which could help reduce the cost of making biodiesel. One method under development is called electrochemical CO₂ reduction (eCO₂R). It uses electricity to turn CO₂ into useful chemicals. However, this method typically requires very pure water and expensive materials like precious metals, making it hard to use on a large scale.

To make the process more affordable and energy-efficient, researchers are testing a different method: the electrochemical glycerol redox reaction (GOR).