The importance of iodine to industry and humans cannot be overemphasized. It plays a crucial role in human metabolic processes. It is widely used for various applications in medicine, material sciences, environmental, and engineering sciences. During the deployment of nuclear technology, there is release of radioiodine in the environment through processes such as reprocessing of nuclear fuel and accidents. Thus, to safeguard the applications of iodine and prevent the leakage of radioiodine into the environment, the capturing and storage of radioiodine are very critical. In our work, ultrahigh radioiodine adsorption capacities of 454 wt% and 1508 mg g(-1) were achieved for iodine vapor and iodine in cyclohexane solution, respectively; using Zinc oxide and nitrogen-doped hierarchical porous carbon (ZnO@NCs), which has a surface area of 1983 m(2)g(-1) synthesized by ultra-sonication of ZIF-8 precursor. These ultrahigh adsorption capacities could be the result of large pore volume of the pores and area of the surface; as well as the electron donor groups such as OH- and O2-, which generated charge transfer between iodine and the adsorbent. The adsorption fits the Freundlich and pseudo-second-order models. These large surface area, ultrahigh adsorption capacity, easy preparation, and good regeneration are indicative of ZnO@NCs as a promising radioiodine adsorbent. [GRAPHICS] .