Adsorption and separation effects of typical metal nuclides on the WS2 surface: a DFT study

The fission products brought about by the growth of nuclear energy is increasing, and their radioactivity will seriously jeopardize human health and pollute the environment. The recycling of radioactive materials has become a problem that needs to be solved nowadays. In this paper, we simulate the adsorption behaviors of typical fission products Cs, Sr, and Co on the surface of WS2 based on first-principle study. 3 x 3 supercell is selected by convergence test and calculate and compare the parameters of adsorption sites, adsorption energy, and charge transfer. At the microelectronic level, we analyze the interactions of WS2 with the three nuclides in detail. In addition, the effect of temperature on the adsorption rate of each nuclide on the WS2 surface is further evaluated by empirical equations. The results show that fissionable metal nuclides tend to be located at the top of the metal atoms of two-dimensional transition metal sulfides (top site of the W atom of WS2), and Co, moreover, has a much larger adsorption energy than that of Cs and Sr due to its binding to W in a form similar to covalent bonds. Moreover, under high temperature conditions, WS2 is more favorable for selecting Co and separating it from Cs and Sr. WS2 is expected to be an excellent material for the separation and recovery of radionuclide Co.