纳米铁催化活化调节煤基活性炭孔结构及机制研究  

Effect and mechanism of regulating pore structure of coal based activated carbon by catalytic activation with nano iron

作　　者：刘娟 姚鑫 庄林生 吴迪 张建奎 王涛 苏显锐 朱文志 LIU Juan;YAO Xin;ZHUANG Linsheng;WU Di;ZHANG Jiankui;WANG Tao;SU Xianrui;ZHU Wenzhi(School of Chemistry and Chemical Engineering,Hefei University of Technology,Xuancheng,Anhui 242000,China;Ningxia Xiangtai New Material Technology Company Limited,Shizuishan,Ningxia 753000,China)

机构地区：[1]合肥工业大学化学与化工学院,安徽宣城242000 [2]宁夏翔泰新材料科技有限公司,宁夏石嘴山753000

出　　处：《中国矿业大学学报》2023年第4期822-830,共9页Journal of China University of Mining & Technology

基　　金：宁夏回族自治区重点研发计划资助项目(2021BEE02012)。

摘　　要：催化活化法调节活性炭孔结构的效果受催化剂分散状态的影响.本文分别采用球磨法、离子交换法和纳米颗粒原位合成法将Fe系化合物引入煤粉,经压块、炭化、CO_(2)活化制备活性炭;利用热重分析仪模拟煤的炭化过程和炭化料的活化过程,采用X射线衍射仪表征炭化料和活性炭的微晶结构、鉴别Fe系物质的存在形式,采用高分辨透射电子显微镜分析Fe系添加剂分布状态和对孔结构发育的影响,采用低温N2吸脱附表征了活性炭的孔结构,并测试了活性炭的亚甲蓝值和焦糖脱色率.结果表明:离子交换法对炭化料的活化反应性影响较小,但显著提高了活性炭的比表面积和微孔孔容,分别由对比样的890.96 m^(2)/g和0.269 cm^(3)/g提升至1071.17 m^(2)/g和0.323 cm^(3)/g,平均孔径由2.19 nm降低至1.40 nm;球磨法和原位合成法向活性炭中引入了30~40 nm的Fe_(3)O_(4)纳米颗粒,加速了活化反应,显著提高了中孔孔容和中孔率,其中原位合成法的Fe3O4纳米颗粒分布更加均匀,中孔孔容达到了0.513 cm^(3)/g;3种方法制备的活性炭吸附性能都达到了较高水平,其中采用离子交换法、微孔强化的活性炭亚甲蓝值达到287.98 mg/g,而球磨法和原位合成法制备的活性炭焦糖脱色率达到了96%以上;上述3种方法均能向低阶烟煤中引入Fe元素,Fe元素在炭化活化过程中均遵循Fe^(n+)→Fe→Fe_(3)O_(4)转变历程,且活化气体CO_(2)优先在Fe系颗粒周围发生选择性氧化反应.纳米颗粒分散状态的Fe可在一定程度上调控活性炭的孔结构.The effect of regulating pore structure of activated carbon by catalytic activation method is highly affected by the dispersion state of catalyst.In this paper,Fe-compounds were introduced into the coal powder by different methods like ball milling,ion exchange and in situ synthesis of nanoparticles to prepare activated carbon samples with different pore structure and adsorption capacities.The carbonization process of coal and the activation process of char were simulated by thermogravimetric analysis.The microcrystalline structure of chars and activated carbons and the existence of Fe element were analyzed by X-ray diffraction.The dispersion of Fe-compounds and its effect on the pore structure of activated carbon were revealed by high resolution transmission electron microscopy.The pore structure of activated carbon was characterized by N_(2)adsorption-desorption isotherms and the methylene blue value and the caramel decolorization rate of activated carbon were also tested.The results show that the reactivity of the char prepared by ion exchange method does not increase much while the derived activated carbon has a BET surface area of 1071.12 m^(2)/g,a micropore volume of 0.323 cm^(3)/g and a average diameter of 1.40 nm,comparing to the Fe-free sample whose values are 890.96 m^(2)/g,0.268 cm^(3)/g and 2.19 nm.Fe_(3)O_(4)nanoparticles of 30—40 nm are formed in the activated carbon prepared by ball milling or in situ synthesis,which accelerate activation reaction and contribute to mesopore development.The mesopore volume of the activated carbon prepared by in situ synthesis increases from 0.218 cm^(3)/g of the Fe-free sample to 0.513 cm^(3)/g.Activated carbon prepared by in situ synthesis has a methylene blue value of 287.98 mg/g while ball milling or in situ synthesis gives activated carbon a caramel decolorization of 96%.Fe element can be successfully introduced by the above three methods and Fe-compounds are transformed into ion and ferroferric oxide after carbonization process and activation process,respecti

关 键 词：活性炭 孔结构 催化活化 铁纳米颗粒 焦糖脱色率 

分 类 号：TQ53[化学工程—煤化学工程] TK114[动力工程及工程热物理—热能工程]