Liljenzin made early contributions to the understanding of the influence of chemistry on core melt accidents[2][3] and participated in international research about iodine chemistry and how to mitigate radioactive releases from nuclear accidents.[4] He also investigated various methods of treatment and separation of spent radioactive fuel as well as chemical aspects of final repository for radioactive waste.[5][6]
Liljenzin was a co-author to Radiochemistry and nuclear chemistry[7] which 2013 was issued in its 4:th edition. He was a co-author to a number of scientific papers[8] about nuclear chemistry with applications to separation of nuclear waste and chemical processes during severe nuclear accidents. His publications has (2023) an h-index of 26.[9]