研究报告
李骞,刘海波,陈天虎,邹雪华,陈冬,庆承松.煅烧菱铁矿制备纳米结构化α-Fe2O3及其NH3-SCR脱硝活性研究[J].环境科学学报,2017,37(7):2482-2489
煅烧菱铁矿制备纳米结构化α-Fe2O3及其NH3-SCR脱硝活性研究
- NH3-SCR performance of nano-α-Fe2O3 derived from thermally treated siderite
- 基金项目：国家自然科学基金（No.41672040,41572029,41472047）；中国博士后科学基金（No.2014M551794）；安徽省自然科学基金（No.1708085MD87）；中央高校基本科研业务费专项资金（No.2014HGCH0007,JZ2017HGTB0196）
- 作者
- 单位
- 李骞
- 合肥工业大学资源与环境工程学院, 纳米矿物与环境材料实验室, 合肥 230009
- 刘海波
- 合肥工业大学资源与环境工程学院, 纳米矿物与环境材料实验室, 合肥 230009
- 陈天虎
- 合肥工业大学资源与环境工程学院, 纳米矿物与环境材料实验室, 合肥 230009
- 邹雪华
- 合肥工业大学资源与环境工程学院, 纳米矿物与环境材料实验室, 合肥 230009
- 陈冬
- 合肥工业大学资源与环境工程学院, 纳米矿物与环境材料实验室, 合肥 230009
- 庆承松
- 1 合肥工业大学资源与环境工程学院, 纳米矿物与环境材料实验室, 合肥 230009;2 滁州学院材料与化学工程学院, 滁州 239000
- 摘要：利用菱铁矿的热分解特性,在空气中不同温度下（400、500、600、700、800 ℃）煅烧天然菱铁矿制备具有纳米尺寸形貌特征的α-Fe2O3,作为NH3选择性催化还原（NH3-SCR）脱硝的催化剂.采用X射线衍射（XRD）、程序升温脱附（NH3-TPD）、X射线光电子能谱（XPS）、紫外-可见漫反射吸收光谱（UV-Vis DRS）等手段对催化剂结构进行表征,并利用气固相催化反应系统对催化剂的NH3-SCR脱硝活性和N2选择性进行评价,同时考察其抗水抗硫及稳定性.结果表明,天然菱铁矿于空气中500 ℃煅烧相变为α-Fe2O3,具有最低的晶体尺寸（约10 nm）、最高的比表面积（39.68 m2·g-1）和最优的脱硝活性；500 ℃煅烧菱铁矿制备的催化剂在250~400 ℃温度窗口内脱硝效率达到100%,并能保持较高的N2选择性,这主要归因于其具有的纳米多孔结构特性和较大的比表面积,以及表面丰富的酸性位点和吸附态氧.当同时存在5% H2O和0.04% SO2时,α-Fe2O3在250~400 ℃区间的脱硝效率高于88%,且在300 ℃下持续反应360 min,脱硝效率维持在75%以上,表明500 ℃煅烧菱铁矿制备的催化剂具有良好的抗水抗硫和稳定性.
- Abstract：Nano-α-Fe2O3 was prepared by annealing siderite in air atmosphere at different temperatures (400, 500, 600, 700, 800 ℃) and used as catalysts for selective catalytic reduction (SCR) of NO by ammonia. The catalytic performance of nano-α-Fe2O3 was evaluated in a laboratory-scale catalytic system and the effect of SO2 and H2O on the catalytic reduction activity was also investigated. The catalysts were characterized by X-ray diffraction (XRD), NH3 temperature programmed desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS), UV Vis diffuse reflectance spectroscopy (UV Vis-DRS), etc. The results showed that natural siderite was transformed into α-Fe2O3 after annealing at 500 ℃ in air atmosphere. The newly formed α-Fe2O3 at 500 ℃ had the lowest crystal size (about 10 nm) and highest specific surface area (39.68 m2·g-1) compared with those of α-Fe2O3 prepared at other temperatures. Meanwhile, the α-Fe2O3 formed at 500 ℃ exhibited a high N2 selectivity and de-NOx performance (100%) at middle-low temperature (250~400 ℃). The nano-porous microstructure, large surface area, plenty acidity sites, and adsorbed oxygen on the surface of the catalyst were responsible for the excellent performance. Besides, the conversion of NO was higher than 88% at 250~400 ℃ and was maintained above 75% at 300 ℃ for 360 min in the presence of 5% H2O and 0.04% SO2. This indicated that this kind of nano-α-Fe2O3 had a good resistance to H2O and SO2 at the experimental conditions.
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