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    FeCl3添加剂作用下煤基压块活性炭的孔结构调控

    Pore structure control of coal based activated carbon prepared by briquetting method in the presence of FeCl_3

    • 摘要: 为了调节煤基压块破碎颗粒活性炭的孔结构,分别以大同烟煤和灵武烟煤为原料,FeCl3为金属添加剂,采用压块工艺制备活性炭,重点考察混合法、浸渍法和离子交换法引入Fe元素对活性炭孔结构和磁性能的影响。利用热重分析了煤的炭化过程和炭化料的活化过程,采用X射线衍射分析了炭化料样品的微晶结构和无机矿物质组成,采用振动样品磁强计和低温N2吸脱附表征了活性炭的磁性能和孔结构。结果表明:混合法和浸渍法引入Fe后,煤在350 ℃前的质量变化速率增大,350~600 ℃ 质量变化速率减小,形成的炭化料石墨化度降低,气化反应性增强,活性炭的比表面积增大,浸渍法使得大同煤基活性炭和灵武煤基活性炭的比表面积分别由672.4 m2/g和498.9 m2/g增至704.6 m2/g和774.1 m2/g。混合法和浸渍法会显著增强活性炭样品的磁性能,其中混合法使大同煤基活性炭和灵武煤基活性炭样品的饱和磁化强度分别由1.343 0 emu/g和2.639 9 emu/g增至4.417 5 emu/g和9.146 5 emu/g。由于原料煤较弱的离子交换能力,离子交换法未能成功引入Fe元素,反而由于溶液呈酸性,降低了原料煤中Ca、Fe系原生矿物质含量,限制了活性炭孔结构发育。

       

      Abstract: In order to adjust the pore structure of coal-based granular activated carbon,a series of activated carbon samples were prepared by briquetting method with Datong bituminous coal and Lingwu bituminous coal as raw materials,using FeCl_3 as the additive.The effects of different Fe introducing methods including mixing,impregnation and ion exchange on the porosity and the magnetic properties of AC samples were investigated.The carbonization process of coal samples and the activation process of carbonized materials were simulated by thermogravimetric analysis.The microcrystalline structure and mineral composition of the carbonized material samples were analyzed by X-ray diffraction.The pore structure and magnetic properties of AC samples were respectively characterized by N2 adsorption-desorption isotherms and vibrating sample magnetometer.The results show that the weight loss rate of coal samples increases before 350 ℃ and decreases between 350 ℃ and 600 ℃ after Fe is introduced into the coal by mixing method and impregnation method. And the graphitization degree of carbonized materials decreases,the gasification reactivity increases,and the specific surface area of activated carbon increases.The BET specific surface area of Datong coal-based activated carbon prepared through Fe-impregnation increases from 672.4 m~2/g to 704.6 m~2/g and the value for Lingwu samples increases from 498.9 m~2/g to 774.1 m~2/g.The magnetic properties of activated carbon samples can be significantly enhanced by mixing method and impregnation method.After Fe is introduced by mixing method,the saturation magnetization of Datong activated carbon and Lingwu activated carbon increases from 1.343 0 emu/g and 2.639 9 emu/g to 4.417 5 emu/g and 9.146 5 emu/g,respectively.Because of the weak ion exchange capacity of the raw coals,Fe is not introduced by ion exchange method.On the contrary,the content of Ca and Fe series primary minerals in raw coal is reduced due to the acidity of the solution,and the pore structure development of activated carbon is limited.

       

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