CIESC Journal ›› 2019, Vol. 70 ›› Issue (11): 4457-4468.DOI: 10.11949/0438-1157.20190331

• Material science and engineering, nanotechnology • Previous Articles     Next Articles

Preparation of mesoporous peat-based activated carbon with peak distribution of 2—5 nm pores

Feng DENG1,2(),Qiang XIE1(),Deqian LIU1,Chaoran WAN1,Xiaoqing HUANG1,Xuemei GU2   

  1. 1. School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing)), Beijing 100083, China
    2. The Coal Chemical Engineering Collaborative Innovation Center of Guizhou Province, Guizhou University of Engineering Science, Bijie 551700, Guizhou, China
  • Received:2019-04-01 Revised:2019-07-24 Online:2019-11-05 Published:2019-11-05
  • Contact: Qiang XIE

2~5 nm孔集中分布泥炭基中孔活性炭的制备

邓锋1,2(),解强1(),刘德钱1,万超然1,黄小晴1,顾雪梅2   

  1. 1. 中国矿业大学(北京)化学与环境工程学院,北京 100083
    2. 贵州工程应用技术学院贵州省煤化工工程协同创新中心,贵州 毕节 551700
  • 通讯作者: 解强
  • 作者简介:邓锋(1986—),男,博士研究生,副教授,dfengkd@126.com
  • 基金资助:
    贵州省教育厅青年科技人才成长项目(黔教合KY字[2018]392);贵州省科学技术基金项目(黔科合LH字[2014]7524号)

Abstract:

Peat was sampled, crushed, ground, impregnated with H3PO4, briquetted and re-crushed, then a series of activated carbon samples were prepared by activation in tube furnace at different temperature and time. Thermogravimetric analysis of H3PO4 impregnated peat samples were performed in a nitrogen environment. The adsorption capacity indexes including iodine value, methylene blue value and caramel decolorization rate were determined, and pore structure, carbonaceous structure, surface chemistry and micro morphology of activated carbon samples were characterized by gas adsorption instrument, Raman spectroscopy, infrared spectrum and scanning electron microscope, respectively. The results show that peat is cross-linked during phosphoric acid activation, and the maximum mass-loss temperature of carbonization/activation drops from around 300℃ to ca. 200℃. With the increase of H3PO4 impregnation ratio and activation temperature, content of irregular graphitic layers in activated carbon increases, and hydroxyls groups on surface of activated carbon decreases. The increase of H3PO4 impregnation ratio results in gradual increase of pore development, absorption performance and volume of 2—5 nm pores. And the increase of activation temperature results in shrink firstly (at 400—550℃) and then destroy ( at 600℃) of pore structure , decrease of absorption performance and volume of 2—5 nm pores. With the increase of activation time, the content of hydroxyl groups on surface of activated carbon firstly reduces greatly (during 120—150 min) and then undergoes irregular changes, meanwhile, the pores firstly expand (during 120—180 min) and then shrink (>180 min), and the absorption performance reduce rapidly after 180 min, at the same time the carbon structure and the volume of 2—5 nm pore section don t show significant change. An activated carbon with a specific surface area of 678.52m2·g-1, volume of 2—5 nm pores of 0.1475 cm3·g-1, accounting for 31.04% of the total pore volume and 70.24% of the mesopore volume, can be derived under the conditions of H3PO4 impregnation ratio 1.5, activation temperature 500℃, and activation time 180 min.

Key words: peat, activated carbon, phosphoric acid, activation, dioxin, flue gas

摘要:

将泥炭破碎、粉磨、浸渍磷酸后,压块成型、再破碎,置于管式炉经不同活化温度、活化时间制得活性炭。对浸渍磷酸后的泥炭样品在氮气下进行热重分析;测定活性炭样品的碘吸附值、亚甲蓝吸附值和焦糖脱色率,利用气体吸附仪、激光拉曼光谱、傅里叶变换红外光谱和扫描电子显微镜分别表征其孔结构、碳结构、表面化学和微观形貌。结果表明:泥炭在磷酸活化过程中发生了交联反应,炭化/活化最大失重温度从300℃附近降低至200℃附近;随着磷酸浸渍比和活化温度的升高,活性炭中的无规则石墨层增多、羟基含量减少;磷酸浸渍比增加时,孔隙逐渐发达、吸附性能增强、2~5 nm孔段孔容增大;活化温度升高时,孔隙先收缩(400~550℃)后发生破坏(600℃)、吸附性能下降、2~5 nm孔段孔容减小;随着活化时间延长,活性炭的羟基含量先大幅减小(120~150 min)后无规律变化,孔隙先扩大(120~180 min)后收缩(>180 min),吸附性能>180 min后迅速下降,碳结构和2~5 nm孔段孔容无显著变化。在磷酸浸渍比1.5、活化温度500℃、活化时间180 min条件下,制得活性炭的比表面积为678.52m2·g-1,2~5 nm孔段的孔容达0.1475 cm3·g-1、占总孔容比率为31.04%、占中孔容比率为70.24%。

关键词: 泥炭, 活性炭, 磷酸, 活化作用, 二英, 烟道气

CLC Number: