Zhao Yongxin, Mann Michael D, Olson Edwin S, Pavlish John H, Dunham Grant E
Department of Chemical Engineering, University of North Dakota, Grand Forks 58202-7101, USA.
J Air Waste Manag Assoc. 2006 May;56(5):628-35. doi: 10.1080/10473289.2006.10464483.
This paper is particularly related to elemental mercury (Hg0) oxidation and divalent mercury (Hg2+) reduction under simulated flue gas conditions in the presence of nitric oxide (NO) and sulfur dioxide (SO2). As a powerful oxidant and chlorinating reagent, Cl2 has the potential for Hg oxidation. However, the detailed mechanism for the interactions, especially among chlorine (Cl)-containing species, SO2, NO, as well as H2O, remains ambiguous. Research described in this paper therefore focused on the impacts of SO2 and NO on Hg0 oxidation and Hg2+ reduction with the intent of unraveling unrecognized interactions among Cl species, SO2, and NO most importantly in the presence of H2O. The experimental results demonstrated that SO2 and NO had pronounced inhibitory effects on Hg0 oxidation at high temperatures when H2O was also present in the gas blend. Such a demonstration was further confirmed by the reduction of Hg2+ back into its elemental form. Data revealed that SO2 and NO were capable of promoting homogeneous reduction of Hg2+ to Hg0 with H2O being present. However, the above inhibition or promotion disappeared under homogeneous conditions when H2O was removed from the gas blend.
本文特别涉及在模拟烟气条件下，一氧化氮（NO）和二氧化硫（SO2）存在时元素汞（Hg0）的氧化和二价汞（Hg2+）的还原。作为一种强氧化剂和氯化试剂，Cl2具有氧化汞的潜力。然而，相互作用的详细机制，特别是含氯（Cl）物种、SO2、NO以及H2O之间的相互作用机制仍不明确。因此，本文所述研究聚焦于SO2和NO对Hg0氧化及Hg2+还原的影响，旨在揭示含氯物种、SO2和NO之间尚未被认识的相互作用，最重要的是在有水存在的情况下。实验结果表明，当混合气中也存在H2O时，SO2和NO在高温下对Hg0氧化有显著抑制作用。Hg2+还原为元素汞形式进一步证实了这一现象。数据显示，在有水存在的情况下，SO2和NO能够促进Hg2+向Hg0的均相还原。然而，当从混合气中除去H2O时，上述抑制或促进作用在均相条件下消失。
