Study on the preparation of magnetic attapulgite and its mercury removal performance
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摘要: 对自然界中广泛存在的凹凸棒土(Atp)进行磁改性,通过沉积-沉淀法制备出磁性氧化铁改性的磁性凹凸棒土(MAtp),采用BET、VSM、XRD以及SEM等手段对其理化性质加以分析,并在固定床实验台上进行模拟烟气脱汞性能测试,研究了铁氧化物含量、反应温度和烟气成分对其除汞能力的影响。结果表明,Atp与磁性物质的复合提高了其对Hg0的脱除能力,并且随铁氧化物含量升高,MAtp脱汞能力逐渐增强;在实验温度区间内,脱汞能力随温度的升高逐渐增强,MAtp对Hg0以化学吸附为主;O2、NO的添加有利于Hg0的脱除,但Hg0穿透率随浓度变化不显著;SO2抑制汞的脱除,并且随浓度的增加,其抑制效果更加明显,但是当NO和SO2共同存在时,NO能明显削弱SO2对脱汞的抑制作用。Abstract: The attapulgite (Atp) widely existed in nature could be modified by magnetism, and a magnetic attapulgite (MAtp) modified by magnetic iron oxide was prepared by deposition-precipitation method. The physical and chemical properties of the magnetic attapulgite were analyzed by BET, VSM, XRD and SEM, and the effects of iron oxide content, reaction temperature and flue gas composition on the mercury removal capacity were studied. The results show that the removal ability for Hg0 is enhanced by the combination of Atp and magnetic materials, and the removal ability of MAtp is gradually improved with the increase in iron oxide content. Moreover, the removal ability of Hg0 is enhanced with the increase of temperature in the test temperature range, and the chemical adsorption of Hg0 is a main factor for MAtp. The addition of O2 and NO is beneficial to the removal of Hg0, but the Hg0 penetration rate does not change significantly with the concentration; while SO2 inhibits the removal of mercury, and the inhibition effect is more obvious with the increase of concentration. However, when NO and SO2 coexist, NO can greatly weaken the inhibition effect of SO2 on mercury removal.
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Key words:
- attapulgite /
- magnetic /
- mercury removal
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表 1 吸附剂的表面结构性质
Table 1 Surface structure and property of the adsorbents
Sample BET surface area A/(m2·g-1) Pore volume v/(cm3·g-1) Average pore diameter d/nm Atp 138.98 0.603 17.35 Iron oxide 85.73 0.274 12.79 1M5Atp 156.51 0.511 13.07 1M2Atp 136.39 0.454 13.22 1M1Atp 111.47 0.450 16.29 -
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