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研究论文

白国梁,陶海兵,蔡思敏,秦伟,毛德棋,王钧伟,董彦杰,张先龙.凹凸棒石(PG)负载V₂O₅催化剂脱除气态Hg⁰的研究[J].环境科学学报,2019,39(7):2369-2376

基金项目：国家自然科学基金（No.21203003，51404014）；安徽省自然科学基金面上项目（No.1708085MB49）；安徽省高校优秀青年人才支持计划重点项目（No.gxyqZD2017062）

摘要：利用凹凸棒石（PG）负载V₂O₅制得V₂O₅/PG催化剂并将其用于脱除烟气中的Hg⁰.在固定床反应器上研究了V₂O₅/PG催化剂脱除Hg⁰的性能，考察了反应温度、汞浓度、空速、烟气成分等对V₂O₅/PG脱除Hg⁰的影响，并利用傅里叶红外光谱、逐级化学提取和程序升温脱附实验分析了V₂O₅/PG上吸附Hg的形态.实验结果表明，V₂O₅/PG催化剂在120~210℃范围内、电厂烟气净化空速和所含汞浓度条件下具有良好的脱除Hg⁰的能力.烟气成分对V₂O₅/PG脱除Hg⁰的影响不同，O₂具有显著的促进作用，而SO₂和H₂O具有一定的抑制作用，NO和CO₂的作用不明显.O₂、SO₂和H₂O共同存在时，促进了Hg⁰的脱除.傅里叶红外光谱、逐级化学提取和程序升温脱附实验的结果证实，V₂O₅/PG上吸附的汞存在不同形态，主要是Hg²⁺的化合物，表明Hg⁰在V₂O₅/PG上的脱除是吸附和催化氧化的共同作用，V₂O₅在V₂O₅/PG脱除Hg⁰的过程中起到了关键作用.

Abstract：A V₂O₅/PG catalyst, which was prepared by supporting V₂O₅ onto palygorskite (PG), was used to remove Hg⁰ from flue gas in a fixed-bed reactor. The effects of temperature, Hg⁰ concentration, space velocity and flue gas components on Hg⁰ removal over V₂O₅/PG were studied. Furthermore, the speciation of Hg adsorbed over V₂O₅/PG catalyst was also characterized by FT-IR, sequential chemical extraction (SCE) and temperature programmed desorption (TPD) experiments. The results showed that V₂O₅/PG catalyst had a high Hg⁰ removal capability in the temperature range of 120~210℃ within a space velocity and the Hg⁰ concentration in flue gas of coal combustion power plant. O₂ showed a promotion effect on Hg⁰ removal over V₂O₅/PG while SO₂ and H₂O showed an inhibition effect, NO and CO₂ showed no obvious effect. The co-effect of O₂, SO₂ and H₂O promoted Hg⁰ removal by V₂O₅/PG. The results of FT-IR, SCE and TPD showed that there were different speciation of Hg over V₂O₅/PG and the main form was Hg²⁺ compounds. These confirmed that Hg⁰ removal over V₂O₅/PG was the co-effect of adsorption and oxidation, in which the catalytic oxidation activity of V₂O₅ played a critical role, i.e. oxidizing Hg⁰ to form Hg²⁺ compound.