The objective of this research is to reveal the mechanism of effective and inexpensive sorbent MnCl2 for elemental mercury (Hg-0) removal from the flue gas. The adsorption behavior of Hg-0 on MnCl2 (11 0) surface was investigated theoretically using Density Functional Theory. The geometry optimization and adsorption energy of Hg-0 on MnCl2 surface were calculated by generalized gradient approximation with Perdew Burke Emzerh functional (GGA/PBE) and DNP basis. Results showed that He adsorption on MnCl2 (1 1 0) surface is chemisorption with adsorption energy of -156.620 kJ/mol. According to Hirshfeld charge analysis, Hg-0 has active interaction with Cl atoms (CI-12, CI-32, CI-44) and Mn-40 atom on MnCl2 (110) surface. The partial density of states (PDOS) analysis further reveals that p- and d-orbitals of Cl atoms strongly hybridize with s- and d-orbitals of Hg-0 atom. The d-orbital of Mn-40 also has essential interaction with Hg-0 atom. Both of them contribute to the stable adsorption system of Hg-0 MnCl2. The equilibrium constant decreases with the increase of temperature, which coincides with data for exothermic adsorption system. For the first time, this study investigated the mechanism of Hg-0 adsorption on metal chloride surface using DFT method. It provides a significance theoretical support for metal chloride application in Hg-0 adsorption and removal. The results obtained in this research are in good agreement with previous experiment. This method can be used to reveal Hg-0 capture mechanism in some complex systems. (C) 2015 Elsevier B.V. All rights reserved.