改性粘土复合材料制备及其对重金属的吸附特性研究

发布时间：2018-06-30 00:08

本文选题：粘土 + 改性　；参考：《东华大学》2017年硕士论文

【摘要】：重金属与人类社会的发展和进步息息相关,并已广泛应用在电气、轻工、机械制造、建筑工业、国防工业等领域,同时也造成了越来越严重的重金属污染。被重金属污染的废水和地表水是全世界的环境难题。吸附法因其简单、方便和高的去除率被认为是一种最常用去除重金属的方法。本文以蒙脱土、埃洛石为材料,通过不同的改性方法,制备了一系列重金属离子吸附剂,并就其对水溶液中重金属离子的吸附行为进行了系统的研究,研究结果如下:(1)采用水热碳化法制得的蒙脱土@碳(MMT@C)复合材料,考察了不同碳源量对吸附效果的影响,并对吸附量最大的MMT/C进行氨基化、羧基化和羟基化改性。采用ATR-FTIR、XRD、比表面积与孔径分布、Zeta电位、SEM等分析方法比较蒙脱土改性前后的结构变化,表征结果证明蒙脱土被改性成功,同时也成功进行了吸附剂的官能团化。通过在相同条件下对溶液中Pb(II)的吸附,评价了不同吸附剂的吸附性能,其中羧基化MMT/C羟基化MMT/C氨基化MMT/CMMT/C。研究了溶液pH值,反应温度、时间、Pb(II)的初始浓度等参数对羧基化MMT/C吸附性能的影响,结果表明,吸附过程符合Langmuir等温线,最大吸附容量为247.85 mg/g;羧基化MMT/C对水中Pb(II)的吸附符合准二级动力学模型,吸附过程为化学吸附,同时热力学参数说明该过程属于自发的、放热反应。羧基化MMT/C表面的-COOH与Pb(II)的络合作用对Pb(II)的去除起主要作用。(2)通过原位生长法在埃洛石表面合成四氧化三铁颗粒,然后用四种不同的硅烷偶联剂对其改性得到新的吸附剂。制备的吸附剂通过TEM、XRD、TGA、ATR-FTIR光谱仪、BET、振动样品磁强计(VSM)和Zeta电位表征,结果表明Fe3O4纳米颗粒已经固定在了埃洛石管壁上,而且硅烷偶联剂也成功嫁接到了埃洛石表面。在四种吸附剂中,苯胺甲基三乙氧基硅烷(KH-42)改性的埃洛石/四氧化三铁(m-HNTs/Fe3O4)无论吸附单溶质的Cr(VI)溶液还是共吸附双溶质的Cr(VI)和Sb(V)溶液,都具有最好的吸附效果。而且在有Cr(VI)存在的情况下,吸附剂对Sb(V)去除率由单溶质系统的67.0%提高到双溶质系统中的98.9%,说明Cr(VI)的存在促进了吸附剂对Sb(V)的吸附。ATR-FTIR和XPS的结果表明:当吸附单溶质Cr(VI)时,N O Cr键被形成在吸附剂表面;而Cr O Sb存在于双溶质系统中,这有助于产生协同促进作用在同时吸附Cr(VI)和Sb(V)时。
[Abstract]:Heavy metals are closely related to the development and progress of human society, and have been widely used in electrical, light industry, mechanical manufacturing, construction industry, national defense industry and other fields, but also caused more and more serious heavy metal pollution. Wastewater and surface water polluted by heavy metals are environmental problems all over the world. Because of its simplicity, convenience and high removal efficiency, adsorption method is considered to be the most commonly used method to remove heavy metals. In this paper, a series of heavy metal ion adsorbents were prepared by using montmorillonite and aloxite as materials, and the adsorption behavior of heavy metal ions in aqueous solution was systematically studied. The results are as follows: (1) the effects of different carbon sources on the adsorption of MMT / C composites prepared by hydrothermal carbonization were investigated, and the most adsorbed MMT / C was modified by amination, carboxylation and hydroxylation. The structural changes of montmorillonite before and after modified montmorillonite were compared by means of ATR-FTIRN XRD, specific surface area and pore size distribution and Zeta potential SEM. The characterization results showed that montmorillonite was successfully modified and the functional groups of adsorbent were also successfully carried out. The adsorption properties of different adsorbents were evaluated by the adsorption of Pb (II) in solution under the same conditions, in which carboxyl MMT / C hydroxylated MMT / C amino MMT / CMMT / C was obtained. The effects of pH, reaction temperature and initial concentration of Pb (II) on the adsorption properties of carboxylated MMT / C were studied. The results showed that the adsorption process was in accordance with Langmuir isotherm. The maximum adsorption capacity is 247.85 mg / g. The adsorption of Pb (II) in water by carboxylated MMT / C accords with the quasi-second-order kinetic model. The adsorption process is chemisorbed, and the thermodynamic parameters indicate that the adsorption is spontaneous and exothermic. The complexation of -COOH and Pb (II) on the surface of carboxylated MMT-C plays a major role in the removal of Pb (II). (2) Fe _ 2O _ 3 particles were synthesized on the surface of Ellosite by in-situ growth, and then modified with four different silane coupling agents to obtain a new adsorbent. The prepared adsorbents were characterized by TGAATR-FTIR spectrometer, vibratory sample magnetometer (VSM) and Zeta potential. The results show that Fe _ 3O _ 4 nanoparticles have been immobilized on the wall of Elosterite tube, and the silane coupling agent has been successfully grafted onto the surface of Elosterite. Among the four adsorbents, aniline methyl triethoxy silane (KH-42) modified Elomite / ferric oxide (m-HNTs / Fe3O4) has the best adsorption effect, either in Cr (VI) solution of monosolute or in Cr (VI) and SB (V) solution of double solute. And in the presence of Cr (VI), The removal rate of SB (V) by adsorbent increased from 67.0% in monosolone system to 98.9% in double solute system, indicating that Cr (VI) promoted the adsorption of SB (V) by Cr (VI). The results of ATR-FTIR and XPS showed that the N O Cr bond was formed on the adsorbent surface when the adsorbent adsorbed Cr (VI). However, the presence of Cr O O Sb in the double solute system contributes to the synergistic effect when Cr (VI) and SB (V) are adsorbed at the same time.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33;X703

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