烟气组分对低温等离子体协同TiO_2光催化工艺氧化Hg~0的影响

采用介质阻挡放电低温等离子体协同TiO2光催化工艺氧化烟气中Hg0,考察了烟气组分对氧化效果的影响。实验结果表明:低温等离子体放电会产生大量近紫外光;在6 k V电压下,低温等离子体协同TiO2光催化工艺时N2/Hg0氛围下Hg0的氧化率达86%,显著高于单一等离子体时的30%;O2和H2O产生的活性粒子会使Hg0氧化率进一步提高,在5 k V电压下,N2/Hg0氛围中添加5%(φ)O2或5%(φ)H2O,低温等离子体协同TiO2光催化工艺时可分别获得96%和94%的氧化率;NO与Hg0的竞争关系会导致作用于Hg0的活性粒子减少,抑制低温等离子体对Hg0的氧化,而在低温等离子体协同TiO2光催化时,抑制作用减弱;在复杂烟气氛围下,低温等离子体协同TiO2光催化对Hg0仍保持了较高的氧化率,3次重复实验的Hg0氧化率均接近92%。

Effects of Flue Gas Compositions on Oxidation of Hg0 by Low Temperature Plasma Assisted TiO2 Photocatalysis Process

Hg⁰ in flue gas was oxidized by low temperature plasma assisted TiO₂ photocatalysis process. The effects of flue gas compositions were studied. The experimental results show that: Near ultraviolet light can be produced by dielectric barrier discharge;When the voltage is 6 kV,the oxidation rate of Hg⁰ in N₂/Hg⁰ atmosphere is 86% by the low temperature plasma assisted TiO₂ photocatalysis process,which is much higher than that by the low temperature plasma process （30%）;Active particles generated by O₂ and H₂O can further enhance the oxidation,and when the voltage is 5 kV,the oxidation rate of Hg⁰ in N₂/Hg⁰ atmosphere with 5%（φ） O₂ or 5%（φ） H₂O are 96% and 94% respectively;The competition between NO and Hg⁰ will cause the decrease of active particle number,therefore the oxidation of Hg⁰ by low temperature plasma is inhibited,but the inhibition effect is weaken by the low temperature plasma assisted TiO₂ photocatalysis process;When Hg⁰ in complex flue gas atmosphere is oxidized by the low temperature plasma assisted TiO₂ photocatalysis process,the Hg⁰ oxidation rate is maintained in high level,and can reach nearly 92% in 3 repeated experiments.