Filtration efficiency of Pd and Ni loaded single-walled carbon nanotubes via the applicability of the adsorption process for the removal NNK, the tobacco-specific nitrosamines, from tobacco smoke were investigated using first-principles calculations. The thermal and mechanical stability of designed nanostructured filter could allow them to compete with typical commercially used. It is expected that the removal efficiency of the proposed nanostructured filter could also provide a promising adsorbent candidate in removing the environmental pollutant. The suggested separation mechanism in this study was discussed with frontier molecular orbital theory, natural bond orbital (NBO) analyses and the density of states in the density functional theory framework. Finally, by the Bader theory of atoms in molecules (AIM), the topological properties of the electron density contributions for intermolecular and intramolecular interactions has been analyzed. Calculations show that the transition metal-loaded SWCNT exhibit strong affinity toward the NNK molecules. (C) 2017 Elsevier B.V. All rights reserved.