CuO/g-C3N4 nanocomposite for elemental mercury capture at low temperature

Graphitic carbon nitride (g-C3N4) with unique and versatile properties has gained increasing research concerns. Here, CuO/g-C3N4 nanocomposite is fabricated and employed for gas-phase mercury (Hg0) removal at low temperature. Pure g-C3N4 performs well toward Hg0 adsorption at 40–200 °C with the optimal Hg0 removal efficiency of ~ 54.5% at 120 °C. CuO-modification can significantly promote the Hg0 capture ability of g-C3N4, probably due to the intimate interface contact of CuO and g-C3N4. The Hg0 removal efficiency of g-C3N4 first increases and then decreases with rising temperature, while temperature shows a promotional effect on Hg0 removal efficiency of CuO/g-C3N4. Hg0 is oxidized into HgO by the chemisorbed oxygen originated from the O–C–N structure of g-C3N4 and the lattice oxygen of CuO. g-C3N4 can be efficiently activated by modifying with CuO toward enhanced Hg0 oxidation ability, presumably attributed to the electron transfer at the interface of CuO and g-C3N4.