Understanding the behavior of radioactive nuclide elements in different environmental conditions is an active area of research. In this work, we have investigated the possible interaction mechanism between carbon nanotubes and uranyl using density functional theory. It is shown that functionalized carbon nanotubes can be used to bind uranyl ions much more efficiently as compared to their unfunctionalized counterpart. The uranyl binding energies are sensitive to the nature of the functional groups rather than the carbon nanotube itself. The binding takes place preferably at the functionalized sites, although pH could determine the strength of uranyl binding. Our predicted results correlate well with the recent experimental uranyl sorption studies on carbon nanotubes. These finding are new and can open up a new era for actinide speciation and separation chemistry using carbon nanotubes.