Simultaneous deSOx and deNOx of marine vessels flue gas on ZnO-CuO/rGO: Photocatalytic oxidation kinetics

Marine Pollution Convention has been updated to prevent the excessive emissions from diesel machine. For high concentrated, large fluxed SO2 and NO photocatalytic oxidation, a novel dual stages oxidationscrubbing process was proposed. The p-n junction ZnO-CuO/rGO ternary catalysts were prepared via the co-precipitation route and supported on reduced graphene oxide (rGO). The UV-vis spectra showed that the bandgap E-g of ZnO-CuO/rGO was notably narrowed to 2.3-2.6 eV for facilitating electron transfer, and its flat band potential of was -0.54 V versus Ag/AgCl. The PL spectra and photocurrent curves revealed that the formation of heterojunctions and the introduction of graphene promoted an efficient separation of the photo-induced charge carriers. The photocatalytic activity of the ZnO-CuO/rGO with 5 wt% GO was evaluated for simultaneous DeSO(x) and DeNO(x), and 97% desulfurization rate and 64% denitration rate could be reached under GHSV 2000 h(-1) for 270 min. In seawater scrubber, ZnO-CuO/rGO(5%) addition made SO32- conversion was 80.72%. The radical scavenging experiments demonstrated that holes (h(+))(-) and superoxide radicals (center dot O-2(-)) contributed most to SO32- photocatalytic oxidation. Kinetic studies showed that SO32- oxidation on ZnO-CuO/rGO fitted the L-H model. The mechanism of photocatalytic oxidation in gas and liquid phases were also proposed to address the reaction pathway. (C) 2020 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.