论文总字数：17202字

摘 要

随着现代化工业，尤其是电子工业和矿业的高速发展，大量含氟废水的排放对环境造成了越来越严重的危害。大气、土壤、水体的氟污染在潜移默化中会对人们生活的各个方面产生消极影响。高浓度含氟废水除氟一直是环保领域的重要研究课题。吸附法因其简单高效且无二次污染的优点一直是各类废水废气处理的首选方法，但也因其吸附剂成本的高昂制约了其应用。考虑到我国是农业生产大国，每年农作物生产必定产生大量秸秆废物，其处理也是一大难题。而秸秆本身具有大量纤维、微孔结构和丰富的表面官能团等各种特性使其成为一种天然吸附剂。如何通过改性使其吸附能力得到提升从而达到廉价资源废物利用是本文的研究思路。本实验采用小麦秸秆为原材料，将其粉碎并在NaOH溶液中预处理后，使用环氧氯丙烷和三甲胺对其进行季铵化改性。实验结果表明吸附效果受温度的升降幅度变化不大，在pH为6左右时吸附率达到峰值。吸附速率很快，按1g/L

的投加量约30min即可达到吸附平衡。用NaCl溶液对吸附后的季铵基改性秸秆进行脱附再生，发现无论NaCl浓度高低，均能实现有效脱附，初次脱附率均在95%左右，但二次脱附和三次脱附脱附率均有整齐降低，分别在74%和60%左右，二次吸附率和三次吸附率也有显著降低。且其吸附氟离子效果受其他竞争离子浓度影响。

关键词：季铵基 秸秆 除氟 吸附

Study on the Adsorption of Fluoride Ion in Water by Quaternary Ammonium Modified Straw

Abstract

With the rapid development of modern industries, especially the electronics industry and mining industry, the discharge of large amounts of fluorine-containing wastewater has caused more and more seriousdamage to the environment. Fluorine pollution in the atmosphere, soil,and water will have a negative impact on people's lives in all itsaspects. The removal of fluorine from high-concentration fluorine-containing wastewater has been an important research topic in the fieldof environmental protection. Adsorption method is always the preferred method for waste water treatment because of its advantages of simple and efficient and no secondary pollution, but it also restricts its application due to the high cost of itsadsorbent. Considering that China is a big country in agricultural production, annual crop production will inevitably produce large amounts of straw waste, and its disposal is also a major problem. The straw itself has a large number of fibers, microporous structure and a wealth of surface functional groups and other characteristics make it anatural adsorbent. How to improve the adsorption capacity by means of modification so as to achieve the waste resource utilization of cheap resources is the research idea of this article. In this experiment,wheat straw was used as raw material, crushed and pretreated in NaOHsolution, and then quaternized by epichlorohydrin and trimethylamine.The experimental results show that the adsorption effect is not greatly changed by the temperature rise and fall, and the adsorption rate reachesa peak at a pH of about 6. Adsorption rate is fast,press 1g/L. The dosage of about 30min can reach the adsorption equilibrium. The desorption and regeneration of the quaternary ammonium-modified straw afteradsorption was performed with NaCl solution. The effective desorption was achieved regardless of the concentration of NaCl. The initial desorption rate was about 95%, but the secondary desorption and the desorption rate were three times. All had a neat reduction, which was around 74% and 60% respectively, and the secondary adsorption rate and tertiary adsorption rate also decreased significantly. And its adsorption fluoride ion effect is affected by other competing ion concentrations.

Keywords: Quaternary Ammonium；Straw；Fluoride removal；Adsorption

目 录

摘 要 I

Abstract II

目 录 III

第一章 绪论 1

1.1 秸秆简介及其危害 1

1.2 国外秸秆处理方向 1

1.3 国内秸秆处理方向 2

1.4 秸秆型吸附剂概念 2

1.5 秸秆型吸附剂研究现状 3

1.6 季铵基改性秸秆 3

1.7 氟离子的危害及处理现状 4

1.8 本课题的提出 5

第二章 实验方法 6

2.1 实验试剂与仪器 6

2.2 实验步骤 7

2.2.1 季铵基改性小麦秸秆阴离子吸附剂的制备 7

2.2.2 氟离子标准溶液的配制 8

2.2.3 氟离子缓冲溶液（TISAB）的配制 8

2.2.4 吸附等温实验 8

2.2.5 吸附pH实验 9

2.2.6 吸附动力学实验 9

2.2.7 竞争离子对吸附的影响 10

2.2.8 脱附和重吸实验 10

2.3 分析与计算 10

2.3.1 吸附剂的表征 10

2.3.2 氟离子浓度的测定 11

2.3.3 实验数据的计算 12

第三章 结果与讨论 13

3.1 吸附剂表征结果 13

3.2 等温吸附实验结果 14

3.3 pH实验结果 16

3.4 动力学实验结果 17

3.5 竞争离子吸附试验 20

3.6 吸附剂的脱附 22

3.7 吸附剂的重吸附 23

第四章 结论和展望 24

4.1 结论 24

4.2 展望 25

参考文献 26

致谢 29

第一章 绪论

1.1 秸秆简介及其危害

农作物的茎、叶、穗部分统称为秸秆，一般含有大量的微孔结构、丰富的纤维素、木质素等物质^[1]，其中含有碳、氢、氮等多种元素，是一种适用领域较广的可再生生物资源。由于人口条件以及相关历史原因，我国秸秆产量高居世界排行榜榜首。从05年起我国秸秆年产量已经稳定在8亿吨以上。秸秆又可细分为粮食作物秸秆、经济作物秸秆以及其他作物秸秆等主要三大类。其中粮食作物秸秆包括小麦秸秆、玉米秸秆、水稻秸秆等，按我国人口分布其分布也相对较广，占据我国大半版图；经济作物包括棉花秸秆、油料秸秆、糖料秸秆等，因其种植技术和地域限制的原因分布面积相对较少，但同时也较为集中。

长久以来，秸秆在我国的农业史上扮演着重要的角色。有关秸秆这样一种食之无味弃之可惜的农业材料的处理，在古代农业生产技术尚不发达时，秸秆除了部分用于饲料、垫圈、堆沤肥外，大部分都作为燃料燃烧掉了^[2-6]。随着科学的进步，人们发现燃烧秸秆的危害远超出想象，主要表现为

1. 引起严重的大气污染，漂浮颗粒物影响人体健康；

（2）引起土壤水分流失，降低土壤肥力，造成耕地枯竭；

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