非平衡等离子体诱导催化剂吸附单质汞

采用非平衡等离子体诱导γ-Al2O3催化剂吸附单质汞，分析了等离子体与催化剂之间的相互作用。结果表明，在放电区域填充催化剂和在气流中加入单质汞均可降低放电的起始放电电压，这是因为放电区域填充催化剂使气体空间放电转变成表面的微放电。催化剂表面可以被等离子放电直接活化，使本身不能吸附单质汞的催化剂产生很强的吸附单质汞的能力。在放电能量密度约为19 J·L-1时，等离子体诱导催化剂吸附单质汞的效率可达94.1%。O2对等离子体诱导催化剂吸附Hg0有促进作用，随着O2浓度的提高，吸附效率随之提高。当气流中含有5% O2时，单质汞的吸附效率可达到98.5%，这是因为气流中存在O2时，经放电生成的等离子体中含有活性氧物种O3和O等，这些活性物质因具有氧化单质汞的能力而增强了单质汞的吸附。此外，催化剂表面O3的分解过程也是强化单质汞的吸附的原因。

Adsorption of elemental mercury in flue gas using non-thermal plasma combined with catalyst

A plasma-catalyst system using a dielectric barrier discharge (DBD) reactor was applied for the adsorption of elemental mercury in flue gas at room temperature and atmospheric pressure. Packing the catalyst in the discharge zone and adding elemental mercury to the gas flow can reduce the initial voltage of the discharge. The packed catalyst in the discharge zone can lead to the generation of filamentary micro-discharges propagating along the pellet surface. The catalyst, which cannot adsorb elemental mercury in a pure N2 atmosphere, can be activated by the plasma discharge, allowing the elemental mercury to be efficiently adsorbed. With a specific energy density of 19 J·L-1, the adsorption efficiency of elemental mercury reached 94.1% in the plasma-catalyst system. The adsorption efficiency increased as O2 concentration in the gas flow increased. When the gas flow contained 5% O2, the adsorption efficiency of elemental mercury improved clearly, up to 98.5%. When O2 is contained in the gas flow, active species such as O3, O, etc., can be produced by plasma discharge and enhance the adsorption of mercury. Furthermore, the formation of active oxygen due to the decomposition of O3 on the surface of the catalyst also can accelerate the oxidation of Hg0. SED increased as Hg0 concentration increased, which may be attributed to the enhanced ionization by the addition of Hg0 and lead to the increase in the amount of adsorbed Hg0.