HONEYCOMB-LIKE MESOPOROUS g-C3N4 FOR ELEMENTAL MERCURY REMOVAL FROM SIMULATED FLUE GAS

Abstract

The [Formula: see text]-conjugated graphitic carbon nitride (g-C3N[Formula: see text] has gained increasing attention due to its unique electronic property, accessible nanoporous framework, chemical and thermal stability. The nanopore structure of g-C3N4 is believed to be favorable for adsorption process owing to the improved mass transfer process. Here, a honeycomb-like mesoporous g-C3N4 is synthesized by direct thermal polymerization of the mixture of urea and ammonium carbonate. It displays an excellent affinity with elemental mercury at reaction temperatures of 50–[Formula: see text]C. The optimal mass ratio of ammonium carbonate/urea is 2 with the highest Hg0 removal efficiency of 87.5% at [Formula: see text]C. NO has a negative effect on Hg0 removal, whereas SO2 slightly reinforces Hg0 adsorption in the presence of oxygen. The Hg0 is probably captured on the carbon atoms of g-C3N4 by producing a covalent carbon-mercury (C–Hg) bond via Lewis acid-base interactions.