Wang Jun-wei, Yang Jian-li, Liu Zhen-yu
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China.
Huan Jing Ke Xue. 2009 Dec;30(12):3455-60.
The adsorption and removal behaviors of gas-phase Hg(0) over V2O5/AC and AC were studied under a simulated flue gas (containing N2, SO2, O2) in a fixed-bed reactor. The influences of the V2O5, loading, SO2 concentration and adsorption temperature on Hg0 adsorption were investigated. The speciation of mercury adsorbed was determined by X-ray photoelectron spectroscopy (XPS). It was found that the V2O5/AC catalyst has a much higher capability than AC for Hg(0) adsorption and removal, mainly because of the catalytic oxidation activity of V2O5. The Hg(0) adsorption capability depends on the V2O5 content of the V2O5/AC catalyst. The amounts of mercury adsorbed increase from 75.9 microg x g(-1) to 89.6 microg x g(-1) (in the absence of O2) and from 115.9 microg x g(-1) to 185.5 microg x g(-1) (in the presence of O2) as the V2O5 loading increases from 0.5% to 1.0%, which are much higher than those over AC under the same conditions (9.6 microg x g(-1) and 23.3 microg x g(-1)). SO2 in the flue gas enhances Hg(0) adsorption over the V2O5/AC catalyst, which is due to the reaction of SO2 and Hg(0) on V2O3/AC. But as the SO2 concentration increases from 500 x 10(-6) to 2000 x 10(-6), the amount of mercury adsorbed has only a slight increase. The optimal temperature for Hg(0) adsorption over the V2O5/AC catalyst is around 150 degrees C, at which the amounts of mercury adsorbed are up to 98.5 microg x g(-1) (in the absence of O2) and 187.7 microg x g(-1) (in the presence of O2). The XPS results indicate the formation of Hg(0) and HgSO4 on the surface of the V2O5/AC catalyst, which confirms the role of V2O5 and SO2.
在固定床反应器中，于模拟烟气（含有N₂、SO₂、O₂）条件下研究了V₂O₅/AC和AC对气相Hg(0)的吸附与脱除行为。考察了V₂O₅负载量、SO₂浓度和吸附温度对Hg⁰吸附的影响。通过X射线光电子能谱（XPS）确定吸附汞的形态。结果发现，V₂O₅/AC催化剂对Hg(0)的吸附和脱除能力远高于AC，这主要归因于V₂O₅的催化氧化活性。Hg(0)的吸附能力取决于V₂O₅/AC催化剂中V₂O₅的含量。当V₂O₅负载量从0.5%增加到1.0%时，汞的吸附量在无氧条件下从75.9 μg·g⁻¹增加到89.6 μg·g⁻¹，在有氧条件下从115.9 μg·g⁻¹增加到185.5 μg·g⁻¹，均远高于相同条件下AC的吸附量（9.6 μg·g⁻¹和23.3 μg·g⁻¹）。烟气中的SO₂增强了V₂O₅/AC催化剂对Hg(0)的吸附，这是由于SO₂与Hg(0)在V₂O₃/AC上发生了反应。但当SO₂浓度从500×10⁻⁶增加到2000×10⁻⁶时，汞的吸附量仅略有增加。V₂O₅/AC催化剂吸附Hg(0)的最佳温度约为150℃，在此温度下，汞的吸附量在无氧条件下可达98.5 μg·g⁻¹，在有氧条件下可达187.7 μg·g⁻¹。XPS结果表明在V₂O₅/AC催化剂表面形成了Hg(0)和HgSO₄，这证实了V₂O₅和SO₂的作用。
