工业水处理 ›› 2022, Vol. 42 ›› Issue (8): 142-148. doi: 10.19965/j.cnki.iwt.2021-1115

• 试验研究 • 上一篇    下一篇

不同晶型二氧化锰去除孔雀石绿的研究

肖勇1(), 郝慧茹2,3(), 李军1, 乐进1, 钟敏3, 张倩3   

  1. 1. 中交第二公路勘察设计研究院有限公司, 湖北 武汉 430056
    2. 武昌首义学院城市建设学院, 湖北 武汉 430064
    3. 武汉理工大学土木工程与建筑学院, 湖北 武汉 430070
  • 收稿日期:2022-07-16 出版日期:2022-08-20 发布日期:2022-09-05
  • 作者简介:

    肖勇(1982— ),高级工程师,硕士,E-mail:

    郝慧茹,助教,硕士,E-mail:

Study on the removal of malachite green by manganese dioxide with different crystalline forms

Yong XIAO1(), Huiru HAO2,3(), Jun LI1, Jin YUE1, Min ZHONG3, Qian ZHANG3   

  1. 1. CCCC Second Highway Survey and Design Research Institute Co. ,Ltd. ,Wuhan 430056,China
    2. School of Urban Construction,Wuchang Shouyi University,Wuhan 430064,China
    3. School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China
  • Received:2022-07-16 Online:2022-08-20 Published:2022-09-05

摘要:

采用水热合成法,通过控制K+浓度得到3种不同晶型的二氧化锰(α-MnO2β-MnO2δ-MnO2)。从微观结构来看,α-MnO2为线状结构,β-MnO2呈丝状结构,δ-MnO2呈二维层状花椰菜状,表面粗糙,比表面积较大。XRD晶型分析表明,β-MnO2显示出许多尖锐的窄峰,结晶度较好;α-MnO2的XRD谱图特征峰变宽变矮,表明存在较小的微晶;δ-MnO2的峰型宽化,结晶度较差,晶粒最小且晶面间距大,有利于催化反应的发生。3种晶型二氧化锰对孔雀石绿(MG)的去除率由高到低依次为δ-MnO2>β-MnO2>α-MnO2,表明δ-MnO2的形貌结构与晶型特征最有利于反应的进行。探究了δ-MnO2体系中pH及污染物初始质量浓度对MG去除效果的影响,结果表明,MG的去除率随pH的增加而增大,随MG初始质量浓度的提高而呈下降趋势。此外,δ-MnO2对孔雀石绿的吸附行为符合Langmuir模型和伪二级动力学模型,属于单层吸附,表面吸附位点分布均匀,吸附速度受化学吸附控制,理论吸附量为40.55 mg/g。

关键词: 二氧化锰, 晶型, 孔雀石绿, 吸附

Abstract:

Three different crystalline forms of manganese dioxide(α-MnO2β-MnO2 and δ-MnO2) were prepared through hydrothermal synthesis method by controlling K+ concentration. It could be observed that α-MnO2 had a linear structure, β-MnO2 had a filamentous structure, and δ-MnO2 had a two-dimensional layered cauliflower shape with rougher morphology and a large specific surface area. XRD analysis showed that β-MnO2 showed many sharp and narrow peaks with good crystallinity. The characteristic peaks of XRD spectra of α-MnO2 became wider and shorter, indicating the presence of smaller crystallites. The peaks of δ-MnO2 was broaden and had poor crystallinity, with the smallest grains and large interplanar spacing, which was favorable to the catalytic reaction. The removal rates of malachite green(MG) by the three manganese dioxide were δ-MnO2> β-MnO2> α-MnO2 in descending order, indicating that the morphological structure and characteristics of δ-MnO2 were most favorable to removal of MG. The effects of pH and the initial mass concentration of pollutants in δ-MnO2 system on the MG removal were investigated, and the results showed that the removal rate of MG increased with the increase of pH and decreased with the increase of initial mass concentration of MG. In addition, the adsorption behavior of δ-MnO2 on MG was in accordance with the Langmuir model and pseudo-secondary kinetic model, which belonged to monomolecular adsorption. The surface adsorption sites were uniformly distributed, and the adsorption rate was controlled by chemisorption with a theoretical adsorption capacity of 40.55 mg/g.

Key words: manganese dioxide, crystal structure, malachite green, adsorption

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