Ensuring environmental protection in and around nuclear facilities is a matter of deep concern. Toward this, layered chalcogenide with CdI₂ crystal structure has been prepared. Structural characterizations of layered chalcogenide suggest ‘topotactic ionic substitution’ as the dominant mechanism behind uptake of different cations within its lattice structure. An equilibration time of 45 min and volume to mass ratio of 30:1 are found to absorb ²³³U, ²³⁹Pu, ¹⁰⁶Ru, ⁸⁵⁺⁸⁹Sr, ¹³⁷Cs and ²⁴¹Am radionuclides to the maximum extents.