高等学校化学学报 ›› 2020, Vol. 41 ›› Issue (2): 284-292.doi: 10.7503/cjcu20190496

• 物理化学 • 上一篇    下一篇

碱活化多孔碳用于分离甲苯及活化/吸附机理

李博文,汪若蘅,黎丽,肖杨()   

  1. 催化转化与能源材料化学教育部重点实验室/催化材料科学湖北省重点实验室, 中南民族大学化学与材料科学学院, 武汉 430070
  • 收稿日期:2019-09-19 出版日期:2020-02-10 发布日期:2019-10-29
  • 通讯作者: 肖杨 E-mail:xiaoyang@scuec.edu.cn
  • 基金资助:
    湖北省自然科学基金资助(BZY16022)

Adsorption of Toluene by Alkali Activated Porous Carbons and Activation/Adsorption Mechanism

LI Bowen,WANG Ruoheng,LI Li,XIAO Yang()   

  1. Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science, College of Chemistry & Material Science, South-Central University for Nationalities, Wuhan 430074, China
  • Received:2019-09-19 Online:2020-02-10 Published:2019-10-29
  • Contact: Yang XIAO E-mail:xiaoyang@scuec.edu.cn
  • Supported by:
    ? Supported by the Natural Science Foundation of Hubei Province, China(BZY16022)

摘要:

采用生物质木质素磺酸钠(SLS)为碳源, 先与硬模板NaCl混合预碳化, 再加入活化剂NaOH在氮气保护下升温至850 ℃碳化, 得到SLS基碱活化的多孔碳吸附剂(SPCN). 将SPCN用于吸附液体石蜡中芳香烃甲苯, 对比研究了不同活化剂加入量对SPCN结构、 性质及吸附效果的影响. 结果表明, SPCN表面具有丰富的官能团和发达的微/介孔结构, 活化剂加入量对比表面积的影响为先增大后减小, 碱/碳质量比为1∶1时比表面积达到最大值(710.4 m 2/g); 吸附量与比表面积呈正相关, 样品SPCN-1的最大吸附量为2875.17 mg/g, 远高于商业吸附剂, 经5次吸附-解吸循环后仍保持92.5%的吸附效率. 探究了活化机理, NaOH、 碳质和气体发生氧化还原反应释放气体留下孔隙, 经充分酸洗、 水洗后得到永久孔道. 最后, 结合扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 拉曼光谱(Raman)、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)和比表面积分析等结果证明了吸附机理主要是孔隙填充效应、 范德华力、 π-π相互作用及电子供/受体作用的共同作用. 首次报道了SPCN应用的新方向并探究了活化与吸附机理, 制备方法简易、 经济, 产品循环稳定性好、 无污染, 有望用于工业化生产.

关键词: 多孔碳, 液体石蜡, 甲苯吸附, 活化机理, 吸附机理

Abstract:

The removal of aromatic compounds have attracted more and more attentions recently due to their toxicity and carcinogenicity. Accordingly, the applications of paraffin liquid on industries, cosmetics, drugs and food are limited for its high aromatic compounds content. A novel adsorbent was conveniently prepared by chemical activation of pre-carbonation sodium lignin sulfonate(SLS), namely, SLS based porous carbon with NaOH activation(SPCN). For the first time we reported that SPCN as adsorbent removed the aromatic compounds from paraffin liquid, in which we took toluene as an example. In this study, the effect of alkali dosage in the range of 0∶1 to 4∶1(the mass ratio of NaOH to carbon) was investigated. The results showed the specific surface area(SSA) and porous structure could be tuned by adjusting the mass ratio of NaOH to carbon, which suggested the tendency of increasing first and then decreasing. The optimum mass ratio of NaOH to carbon was proved to be 1∶1 and SPCN-1 had a large SSA of 710.4 m 2/g compared to 316.2 m 2/g of 0∶1 and 518.3 m 2/g of 4∶1. Adsorption capacity was proportional to specific surface area and was calculated as 1684.74, 2875.17 and 1729.64 mg/g corresponding to 0∶1, 1∶1 and 4∶1, respectively. SPCN-1 not only had a better adsorption capacity than several commercial adsorbents but also maintained 92.5% adsorption efficiency after five adsorption and desorption cycles. In addition, the activation and adsorption mechanism were deeply discussed. Overall, we proposed a facile and cheap method to remove the toluene from paraffin liquid with high cyclic stability and low pollution firstly, which provided a promising strategy for industrialization.

Key words: Porous carbon, Paraffin liquid, Toluene adsorption, Activation mechanism, Adsorption mechanism

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