XJIPC OpenIR  > 环境科学与技术研究室
改性蛭石复合材料的制备及其重金属吸附性能研究
顾士庆
Thesis Advisor王传义
2018-05-25
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name硕士
Degree Discipline材料工程
Keyword蛭石 胺基功能化 表面改性 重金属吸附 Pb(Ii)有效吸附
Abstract

天然粘土矿物材料因具有离子交换能力、良好的化学稳定性和机械稳定性,在重金属污染物去除应用领域具有一定优势,但因其吸附容量较低、悬浮性和分散性等劣势都在一定程度上抑制了粘土的开发与利用。许多研究已经表明,天然粘土的重金属吸附容量随着改性的进行而增加。作为新疆优势资源的蛭石矿物,其比表面积大,阳离子交换容量高,对重金属离子、染料分子等的吸附性能好,能够作为表面改性的基体,从而获得性能优异的改性蛭石纳米复合材料。为此,本论文结合酸改性和有机改性技术,开展蛭石纳米复合重金属吸附材料的可控制备研究,采用热力学和动力学模拟方法探究蛭石复合材料对重金属离子的吸附过程,并根据模拟实验结果,设计系列改性蛭石纳米复合重金属吸附材料;并以环境中四种常见的重金属污染物Pb(II)、Cd(II)、Cu(II)和Hg(II)离子为代表研究其环境功能与作用机制。本论文的主要研究内容及结论如下:(1)通过结合酸改性和有机改性在蛭石的表面接枝了大量对铅离子具有吸附作用的功能性-NH2基团,得到了接枝-聚丙烯酰胺/蛭石复合材料(g-PAM/OVerm)。-NH2接枝过程主要包括丙烯酰胺的聚合反应和三乙烯四胺的Mannich接枝反应,这些改性反应明显地改善了蛭石对铅离子的吸附能力。同时,制备的g-PAM/OVerm相比于Zn(II)、Cd(II)和Cu(II)等离子,对Pb(II)具有明显的吸附选择性。SEM、EDS、热分析、FTIR和BET的分析表征技术可以联合说明-NH2基团被成功地接枝在蛭石的表面。同时准二级动力学模型和Langmuir模型分别可以很好地拟合g-PAM/OVerm吸附Pb(II)的动力学和热力学行为。同时热力学实验测得g-PAM/OVerm对Pb(II)的最大吸附容量为219.4 mg·g-1。g-PAM/OVerm具有可循环再生的性质,经过四次的吸附-脱附循环后的吸附效率仍然保持在90%以上。(2)先后采用酸改性和有机硅烷偶联剂改性方式制备了APTES-Verm吸附剂。实验结果表明无机酸改性在Verm的表面暴露了大量Si-OH基团,为有机改性中APTES接枝到Verm的表面提供桥梁基础,并且有机改性得到的APTES-Verm含有大量-NH2基团。同时相比于a-Verm,APTES-Verm对Cu(II)、Cd(II)、Pb(II)、Hg(II)的吸附量得到提升,并对Pb(II)的吸附具有特殊的吸附选择性,其吸附容量达到了210.865 mg/g,远远大于对Cu(II)、Cd(II)、Hg(II)的吸附容量。该材料不仅对未来重金属水处理方面有借鉴作用,也为蛭石等粘土矿物的合理开发和利用提供了理论指导和依据。(3)通过酸改性制备了酸化蛭石,并且运用有机改性反应在酸化蛭石的表面连接了对Pb(II)具有吸附作用的有机官能团,制备了三种蛭石复合材料吸附剂(Verm-NH2、Verm-COOH和Verm-SH)。SEM、EDS、热分析、FTIR和BET的分析表征技术可以说明-NH2、-COOH和-SH基团被成功地连接在蛭石的表面。三种蛭石复合材料吸附剂对单一Pb(II)的对比吸附实验发现,相比于Verm-COOH和Verm-SH复合材料,Verm-NH2对Pb(II)的吸附量最大,其吸附量大小顺序为Verm-NH2>Verm-SH>Verm-COOH,这说明相对于有机官能团-COOH和-SH,-NH2基团对Pb(II)的结合能力更强。同时准二级动力学模型和Langmuir模型可以分别很好地拟合Verm-NH2吸附Pb(II)的动力学和热力学行为。此章工作可以为有机基团改性无机吸附剂在重金属吸附领域的机理研究提供一定的借鉴,也为粘土矿物的合理开发和利用提供了理论指导和依据。

Other Abstract

Natural clay mineral materials have some advantages in the field of heavy metal pollutants removal because of their ability of ion exchange, good chemical stability and mechanical stability. However, the development and utilization of clay are restrained to some extent because of their low adsorption capacity, suspension and dispersion. The vermiculite minerals, which are the dominant resources of Xinjiang, have large specific surface area, high cation exchange capacity, good adsorption properties to heavy metal ions and dye molecules, and can be used as surface modified substrates to obtain modified vermiculite nanocomposites with excellent performance. Therefore, this thesis combines acid modification and organic modification technology to study the controllable preparation of vermiculite composites. The adsorption process of heavy metal ions by vermiculite composites is investigated by thermodynamic and kinetic simulation methods. Based on the simulated experimental results, a series of modified vermiculite composite for heavy metal removal are designed. The main contents and conclusions of this thesis are as follows:(1) Graft Polyacrylamide/vermiculite composite (g-PAM/OVerm) was obtained by grafting a large number of functional -NH2 groups on the surface of vermiculite by combining acid modification and organic modification on the vermiculite surface. The -NH2 grafting process mainly includes the polymerization of acrylamide and the Mannich grafting reaction of triethylene tetramine, which obviously improves the adsorption capacity of vermiculite to lead ions. At the same time, compared with Zn(II), Cd(II) and Cu(II) ions, g-PAM/OVerm has obvious adsorption selectivity for Pb(II). SEM, EDS, thermal analysis, FTIR and BET analysis techniques can be combined to show that -NH2 groups were successfully grafted on vermiculite surface. Meanwhile, the pseudo-second-order kinetic model and the Langmuir model can well simulate the kinetics and thermodynamics behaviors of g-PAM/OVerm for Pb(II) adsorption. At the same time, the maximum adsorption capacity of g-PAM/OVerm for Pb (II) was 219.4 mg g-1. The adsorbent g-PAM/OVerm is recyclable, and its adsorption efficiency is still over 90% in the fifth adsorption-desorption cycle.(2) APTES-Verm adsorbent was prepared by acid modification and organic silane coupling agent modification. The experimental results show that a large number of Si-OH groups are exposed on the surface of Verm by inorganic acid modification, which provides a bridge basis for the grafting of APTES onto the surface of Verm in organic modification, and the organic modified APTES-Verm contains a large number of -NH2 groups. At the same time, compared with a-Verm, the adsorption capacity of APTES-Verm for Cu(II), Cd(II), Pb(II) and Hg(II) is improved, and the adsorption for Pb(II) shows special adsorption selectivity; the adsorption capacity is 210.865 mg/g, which is much higher than Cu(II), Cd(II) and Hg(II) ions.(3) Acidified vermiculite is prepared on the basis of the 3rd chapter, and organic functional groups including -NH2, -COOH and -SH are connected to the surface of acidified vermiculite by organic modification reaction, and three kinds of vermiculite composite adsorbents are prepared respectively (Verm-NH2, Verm-COOH and Verm-SH). SEM, EDS, thermal analysis, FTIR and BET analysis techniques can be combined to show that -NH2, -COOH and -SH groups were successfully grafted on vermiculite surface, respectively. The adsorption experiments of three vermiculite composite adsorbent on single Pb (II) were compared. Compared with Verm-COOH and Verm-SH composites, Verm-NH2 has the largest adsorption capacity for Pb (II), and the order of adsorption capacity is Verm-NH2>Verm-SH>Verm-COOH, which indicates that the -NH2 group has stronger binding capacity with Pb(II) than -COOH and -SH. Meanwhile the pseudo-second-order kinetic model and Langmuir model can well simulate the kinetics and thermodynamics of Verm-NH2 for Pb(II) adsorption. This part of the work can provide some experience for the study of the mechanism of organic group modified adsorbents in the field of heavy metal adsorption, and provide theoretical guidance for the rational development and utilization of clay minerals.

Document Type学位论文
Identifierhttp://ir.xjipc.cas.cn/handle/365002/5482
Collection环境科学与技术研究室
Recommended Citation
GB/T 7714
顾士庆. 改性蛭石复合材料的制备及其重金属吸附性能研究[D]. 北京. 中国科学院大学,2018.
Files in This Item:
File Name/Size DocType Version Access License
改性蛭石复合材料的制备及其重金属吸附性能(5079KB)学位论文 开放获取CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[顾士庆]'s Articles
Baidu academic
Similar articles in Baidu academic
[顾士庆]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[顾士庆]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.