Elemental Mercury Removal by MnO2 Nanoparticle-Decorated Carbon Nitride Nanosheet

Carbon nitride nanosheet (CNNS) is facilely synthesized via a two-step thermal oxidative etching approach and then decorated with MnO2 nanoparticles via incipient wetness impregnation method for Hg-0 removal at low temperature. Pristine CNNS exhibits a good Hg-0 adsorption performance associated with the optimal He removal efficiency of similar to 65.8% at 150 degrees C due to its two-dimensional planar structure and big surface area. MnO2 decoration can greatly enhance the Hg-0 removal performance of CNNS, presumably ascribed to the improved electron transfer at the interface of MnO2 and g-C3N4. 10MnO(2)/CNNS presents a superior Hg-0 oxidation ability with He removal efficiencies all above 91% within the temperature range of 90-240 degrees C. The long-term test and XPS analysis disclose that 10MnO(2)/CNNS is a cost-effective catalyst/sorbent for oxidation removal of elemental mercury. The gaseous He is oxidized into Hg-0 by the lattice oxygen of MnO2, which is the dominant active site for Hg-0 oxidation via redox couple of Mn4+/Mn3+.