CIESC Journal ›› 2015, Vol. 66 ›› Issue (S1): 228-236.DOI: 10.11949/j.issn.0438-1157.20150134

• 分离工程 • 上一篇    下一篇

热改性层状双氢氧化物吸附除Cr(Ⅵ)性能

张颖新, 周涛, 毛娟, 吴晓晖, 袁蓁   

  1. 华中科技大学环境科学与工程学院, 湖北 武汉 430074
  • 收稿日期:2015-01-27 修回日期:2015-02-03 出版日期:2015-06-30 发布日期:2015-06-30
  • 通讯作者: 周涛, 吴晓晖
  • 基金资助:
    国家自然科学基金项目(21407052);"十二五"国家科技支撑计划(2015BAB01B04)。

Efficient removal of Cr(Ⅵ) by thermal-modified layered double hydroxides (LDHs): adsorption behaviors, effect parameters and comparison with original LDHs

ZHANG Yingxin, ZHOU Tao, MAO Juan, WU Xiaohui, YUAN Zhen   

  1. School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
  • Received:2015-01-27 Revised:2015-02-03 Online:2015-06-30 Published:2015-06-30
  • Supported by:
    supported by the National Natural Science Foundation of China (21407052) and Key Project in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (2015BAB01B04).

摘要: 通过共沉淀法制备得到镁铝层状双氢氧化物(LDHs), 并在450℃高温下进行热改性处理(即C-LDHs)。系统性比较了上述两种材料除Cr(Ⅵ)的吸附动力学及等温线模型, 并考察温度、pH、Cr(Ⅵ)初始浓度等重要因素对吸附效果的影响。使用XRD、SEM、FT-IR和TG-DTG等对两种吸附材料进行了表面特性表征。结果表明, 热改性后C-LDHs的表面性质发生了巨大变化。但其吸附过程仍符合Langmuir吸附等温式。C-LDHs对Cr(Ⅵ)的最大吸附量为105.26 mg·g-1, 远大于LDHs的吸附量(20.66 mg·g-1)。本文结果表明, 对层状双氢氧化物进行经济方便的热改性可大幅度增强其对Cr(Ⅵ)的吸附性能, 对层状双氢氧化物的工业化应用具有重要的参考价值。

关键词: 镁铝层状双氢氧化物, 热处理, 六价铬, 纳米材料, 吸附, 废水

Abstract: The pollution of hexavalent chromium (Cr(Ⅵ)) is of particular environmental concern because of its toxicity and carcinogenic effect. In this study, Mg-Al layered double hydroxides (Mg-Al LDHs) were prepared by the co-precipitation method. It was found that a thermal modification process of the Mg-Al LDHs (calcined LDHs, C-LDHs) could improve obviously the adsorption capacity of Cr(Ⅵ). The equilibrium isotherms showed that the adsorption of Cr(Ⅵ) using either LDHs or C-LDHs could be well fitted with the Langmuir model. The maximum Cr(Ⅵ) uptake capacity of C-LDHs and original LDHs was 105.26 and 20.66 mg·g-1 at 30℃, respectively. The pseudo-second-order model could be used to describe the adsorption of Cr(Ⅵ) on both C-LDHs and LDHs. Effect of important parameters such as reaction temperature, pH and initial Cr(Ⅵ) concentration was also investigated, and it was found that the reaction temperature has slight effect on the adsorption capacity of the C-LDHs. This could be ascribed to the nature of the Cr(Ⅵ) adsorption reaction by the C-LDHs. Characterizations of the LDHs and C-LDHs by XRD, SEM, FT-IR and TG-DTG evidenced that the surface properties of LDHs particles could be successfully varied by the calcined treatment of LDHs.

Key words: Mg-Al layered double hydroxides (Mg-Al LDHs), calcined treatment, hexavalent chromium (Cr(Ⅵ)), nanomaterials, adsorption, waste water

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