FeN3-embedded carbon as an efficient sorbent for mercury adsorption: A theoretical study

The control of mercury (Hg-0) is one of the most important environmental problems but a long-standing challenge in environment. Current research efforts for mercury removal mainly focus on the development of economical, effective, and recyclable sorbents, while the carbon-based metal sorbents with magnetism have been rarely studied. Here, we proposed the FeN3-embedded carbon (FeN3-C) as the efficient sorbent for Hg-0 adsorption from first-principles computations. Our calculation results show that the incorporated FeN3 in carbon endows the carbon with magnetic and metallic properties and that the gas phase Hg-0 can be efficiently adsorbed on FeN3-C through the chemisorption mechanism with the adsorption energy of -66.27 kJ/mol. Moreover, the unoccupied d-orbital of Fe in FeN3-C can hybridize with the Hg s- and d-orbitals and accept electron density from the Hg sand d-orbitals, which is the "acceptance" process between Hg-0 and FeN3-C. Additionally, according to the equilibrium constant, Hg-0 adsorption on FeN3-C is beneficial at low temperature. Our theoretical study not only reveals that the nonprecious FeN3-embedded carbon possesses great promise to serve as an efficient sorbent for Hg-0 adsorption, but also provides a coordination-engineered strategy for searching more efficient carbon-based metal sorbents.