论文总字数：18845字

摘 要

氟元素是保障人类身体健康不能缺少的微量元素之一，但摄入体内过量的氟可能会身体的新陈代谢产生影响，从而导致健康问题。随着现代工业、农业生产的迅速发展，水体中氟污染的程度日益严重，带来了巨大的环境风险。

层状复合金属氢氧化物（LDHs）拥有优异的阴离子交换性能和良好的热稳定性，具有较高的除氟效率。其中作为制备Mg-Al LDH吸附剂的原料，MgCl₂以及AlCl₃具有来源广泛，成本低廉，经济实惠等特点本论文通过共沉淀法制备Mg-Al LDH，并对其去除氟离子的能力进行了研究。

通过批量吸附实验（pH、等温线、竞争性、动力学、脱附再生等实验）进行研究。等温线数据表明温度越高，Mg-Al LDH对溶液中氟离子的吸附效果越好，但吸附效果随温度升高的变化不显著，促进效果不明显。竞争性实验表示Mg-Al LDH去除氟离子较适宜在酸性环境中进行。氟离子的竞争离子氯离子一定程度上影响了Mg-Al LDH的吸附效果。动力学实验结果表示，Mg-Al LDH作为吸附剂具有较快的吸附效率，吸附达到平衡所需的时间约为300分钟，实验数据符合准二级动力学模型。脱附再生实验证明了该吸附剂脱附效率较高且具有良好的循环再生能力。本论文系统评价Mg/Al层状复合金属氢氧化物对模拟含氟废水的净化性能，从而为高效除氟吸附剂的研制提供参考。

关键词：吸附 Mg-Al LDH 氟

The preparation of Mg/Al layered double hydroxides for fluoride removal from water

Abstract

Fluorine is one of the indispensable trace elements that protect human health, but excessive fluoride is intook in the body may affect the body's metabolism, leading to health problems. With the rapid development of modern industry and agricultural production, the degree of fluorine pollution in water bodies has become increasingly serious and brought about huge environmental risks.
Lamellar composite metal hydroxides (LDHs) have excellent anion exchange performance and good thermal stability, and have a high efficiency of fluoride removal. As raw materials for preparing Mg-Al LDH adsorbents, MgCl₂ and AlCl₃ have a wide range of sources, low cost, and economic benefits. In this paper, Mg-Al LDH was prepared by co-precipitation method and its ability to remove fluoride ions was studied.

The results of batch adsorption experiments (pH, isotherm, kinetics, competition, desorption regeneration, etc.) showed that the higher the temperature, the better the adsorption effect, but the effect of temperature increase on the adsorption effect is not significant. Its removal of fluoride ions is more suitable in an acidic environment. The competitive ion chloride ion of fluoride ion affected the adsorption effect of Mg-Al LDH to some extent. The kinetic experimental results show that Mg-Al LDH as a sorbent has a fast adsorption efficiency, and the time required for adsorption to reach equilibrium is about 300 minutes. The experimental data is in line with the pseudo-second-order kinetic model. The desorption regeneration experiment has been proved that the desorption efficiency of the adsorbent is high and it has good recycling ability. This thesis systematically is evaluated that the purification performance of Mg/Al layered composite metal hydroxides on simulated fluorine-containing outlet water, thus providing references for the development of

highly efficient fluorine-removing adsorbents.
 

Key Words: Adsorption; Mg-Al LDH; fluorine

目 录

摘 要 Ⅰ

Abstract Ⅱ

第一章 绪论 1

1.1研究背景 1

1.1.1水体中氟的危害 1

1.1.2水体除氟技术研究现状 2

1.2层状复合金属氢氧化物吸附剂 3

1.3 Mg/Al LDH吸附剂 5

1.4研究思路和技术方法 5

第二章 实验材料与方法 7

2.1实验仪器及试剂 7

2.1.1实验仪器 7

2.1.2实验试剂 7

2.2实验方法 7

2.2.1氟标准曲线的测定 7

2.2.2吸附剂Mg-Al LDH的制备及表征 8

2.2.3初始浓度和温度对吸附效果的影响 8

2.2.4 pH对吸附效果的影响 9

2.2.5其他阴离子对吸附效果的影响 9

2.2.6吸附动力学实验 9

2.2.7脱附再生实验 10

第三章 实验结果与讨论 11

3.1吸附剂的外观及材料表征 11

3.2初始浓度和温度对吸附效果的影响 12

3.3 pH对吸附效果的影响 14

3.4其他阴离子对吸附效果的影响 15

3.5吸附动力学实验 16

3.6脱附再生实验 18

3.7小结 20

第四章 结论和展望 21

4.1结论 21

4.2展望 21

参考文献 23

致 谢 25

第一章 绪论

1.1 研究背景

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