Van Rooij is studying an alternative to the use of fossil energy in chemical processes. He hopes to contribute to the restoration of the energy balance by doing so. "This energy transition has driven all of my scientific work over the last 20 years," van Rooij explains.

The sustainable approach is known as plasma chemistry. The method heats molecules to exceptionally high temperatures using fossil-free electricity. The molecules become so hot that they disintegrate into pieces. These pieces can then recombine to generate novel molecules. As a result, plasma chemistry modifies existing chemical processes to use fewer raw fossil materials. More is feasible with plasma chemistry; for example, the technology may transform carbon dioxide from the air back into fuel, allowing for the availability of sustainable electrical energy in other forms.

Van Rooij's research is part of the Circular Chemical Engineering department at the Brightlands Chemelot Campus in Geleen. The campus houses the brand-new plasma laboratory, where the scientist conducts research and refines his plasma procedures. In addition, the department offers Maastricht University's new bachelor's degree in Circular Engineering. "We are literally and figuratively in the middle of our South Limburg process chemistry," he explains. "I say emphatically, "our" industry here." The South Limburg region understands industry and society better than anyone."