After earning his doctoral degree, Kanu started a postdoctoral fellowship at Washington State University. He worked alongside Herbert H. Hill, Jr. on the development of ion mobility mass spectrometry. He proposed that this work could be used to reduce false positives in airport screening for explosives and drugs, and also showed that it was possible to separate drugs using the drift gas selectivity of ion-mobility spectrometry–mass spectrometry, and this work has since been cited over 1000 times. He has applied ion-mobility spectrometry–mass spectrometry to identify environmental pollutants in both indoor air and contaminated water. He has created a novel sampling system that incorporates a polydimethylsiloxane (PDMS) membrane and nanoparticles for one-step sampling, isolation, separation and desorption of environmental pollutants. 
Alongside his academic research, Kanu works to improve the representation of minority students in science. He leads undergraduate research programmes and supports student chapters of the American Chemical Society and National Organization for the Professional Advancement of Black Chemists and Chemical Engineers. Kanu leads the annual Extreme Forensic Instrumentation Experience Lab at Winston-Salem State University, which sees high school seniors take part in a research project themed around a crime drama. He works with Chemists Without Borders to introduce young people in Sierra Leone to practical chemistry skills and help to rebuild the education system after the Civil War. As part of this work, Kanu created affordable green chemistry lab kits, which included materials and manuals.