活性炭负载纳米零价铁的合成及对六氯苯的吸附研究

VIP免费

3.0 侯斌 2024-11-19 4 4 6.59MB 80 页 15积分

侵权投诉

活性炭负载纳米零价铁的合成及对六

氯苯的吸附研究

摘要

六氯苯（HCB）是 12 种持久性有机污染物之一，具有致癌、致畸和致突变

效应，损伤肝脏，造成生长发育停滞，甚至可遗传性。治理含 HCB 的污染水体

对环境保护和人类安全维护有重要意义。活性炭和纳米零价铁（nZVI）应用广泛，

并能高效吸附降解有机物，降低或消除其毒性。本研究分别采用浸渍法和还原法

合成活性炭负载 nZVI（nZVI/AC），确定其最佳合成条件，并探讨该复合材料对

以HCB 为代表的有机物的去除效果及机理。表征和吸附平衡实验结果表明铁碳

质量比、加热时间和乙醇投加量等因素对铁的负载过程有重要影响。活性炭负载

纳米零价铁后，其比表面积和孔体积下降，降低程度与铁负载量有关。但高铁负

载量并不一定有助于 HCB 降解。浸渍法合成材料时，取铁碳比为 0.84:1，加热 5

h（命名 nZVI/AC-I），对 HCB 的去除效率最高，最大吸附量为 4.87 mg/g；而吸

附法合成的复合材料则在铁碳比 0.42:1，乙醇含量 26.78%时（命名 nZVI/AC-

A），HCB 去除效果最佳，最大吸附量可达 10.22 mg/g。与未改性活性炭相比，

nZVI/AC 对HCB 的吸附能力显著提高。

经过优化实验确定两种方法的最佳合成条件后，进行批式实验探讨不同环境

条件因素如反应时间、溶液 pH 以及水中阴阳离子的存在等对 HCB 去除的影响。

结果表明 nZVI/AC 能快速有效地降低水中 HCB 浓度，动力学过程符合准二级动

力学模型。pH 影响实验表明，由于铁负载量不同，nZVI/AC-I 在pH 5-7 时，效果

最佳，而 nZVI/AC-A 在酸性条件吸附效果更佳。水中 HCO3-、Cl-、SO42-和Mg2+

在不同程度上促进 nZVI/AC 降解 HCB，NO3-抑制 nZVI/AC-A 吸附 HCB，促进

nZVI/AC-I 的吸附反应；而一定浓度的 Fe2+和Cu2+提高 nZVI/AC-A 对HCB 的去除

率，降低 nZVI/AC-I 的反应能力。

另外，研究还探讨了 HCB 的降解产物和途径。HCB 的降解为逐级脱氯过程，

由于 nZVI/AC 的高效性，可将 HCB 降解为一氯苯（MCB）。但由于四氯苯

（TeCB）和二氯苯（DCB）的对称结构，性质稳定，为主要产物。两种反应路

径相似，但 nZVI/AC-A 的活性更强，对 HCB 的反应更彻底，吸附效率更高。

关键词：活性炭纳米零价铁合成条件六氯苯吸附

ABSTRACT

Hexachlorbenzene (HCB), one of the 12 persistent organic pollutions, has

carcinogenic, teratogenic and mutagenic effects. It could lead to kidney and liver

damage, stagnant growth, and even be genetic. It is important to environmental

protection and human safety maintenance for the HCB reduction in wastewater.

Activated carbon and nano zero-valent iron (nZVI) are widely used as the effective

dehalogenation ability to lower or eliminate the organic matters’ toxity. In this research,

impregnation method and adsorption method were adopted to synthesis activated carbon

supported nZVI (nZVI/AC), determining the optimal synthesis condition. And the HCB

removal efficiency, representing organic matters, and mechanism by composite

materials were investigated. Characterization and adsorption equilibrium experiment

results showed Fe:C mass ratio, heat time and ethanol additive amount had significant

effect on the iron loading. That specific surface area and pore volume of activated

carbon have decreased after nZVI loading, and the reduction range is related to iron

content. But high iron contend does not necessarily contribute to HCB degradation. For

nZVI/AC-I prepared by impregnation method, when Fe:C ratio at 0.84:1 and heat time

at 5 h was selected, the HCB removal efficiency was highest and maximum adsorption

capacity reached 4.87 mg/g. But to adsorption method, nZVI/AC-A particle with Fe:C

ratio at 0.42:1 and ethanol dosage at 26.78% had the optimal HCB removal efficiency

and maximum HCB adsorption capacity 10.22 mg/g. Comparing with virgin activated

carbon, the HCB removal efficiency by nZVI/AC was greatly improved.

By optimizing the synthesis conditions of two methods, batch experiments were

conducted to discuss the effects of different environmental conditions on HCB removal,

such as reaction time, solution pH and the presence of cation and anion in water. The

results illustrated nZVI/AC particles were capable of reducing the HCB concentration

quickly and effectively, and that adsorption kinetics was consistent with pseudo second

reaction model. The pH experiment showed as the different iron content, nZVI/AC-I

had the best efficiency at pH 5~7, but it was best at acidic condition for nZVI/AC-A.

The HCO3-, Cl-, SO42- and Mg2+ in water enhanced the HCB removal by nZVI/AC to a

variable extent; but NO3- inhibited the HCB adsorption reaction of nZVI/AC-A, and

improved that of nZVI/AC-I; And Fe2+ and Cu2+ improve the removal efficiency of

nZVI/AC-A, but decreased that of nZVI/AC-I.

In addition, this study also investigated the HCB degradation products and

pathway. It was a clear stepwise dechlorination pattern. Due to the high efficiency of

nZVI/AC, HCB could be degraded to monochlorobenzene (MCB). But as the

symmetric structure of tetrachlorobenzene (TeCB) and dichlorobenzene (DCB), stable

nature, they were main products. The two reaction pathways were similar, but the

activity of nZVI/AC-A was stronger, so the HCB reaction was more thoroughly and

removal efficiency was higher.

Key Word: activate carbon, nano zero-valent iron, synthesis condition,

hexachlorobenzene, adsorption

目

录
摘  要
ABSTRACT
第一章 绪 论...................................................................................................................1
1.1 研究背景和现状......................................................................................................1
1.1.1 六氯苯（HCB）的性质及危害.......................................................................1
1.1.2 HCB 的污染现状..............................................................................................2
1.1.3 HCB 的去除技术..............................................................................................3
1.2 纳米零价铁（nZVI）.............................................................................................6
1.2.1 nZVI 的性质及应用.........................................................................................6
1.2.2 nZVI 的改性.....................................................................................................8
1.3 活性炭.....................................................................................................................9
1.3.1 活性炭的性质...................................................................................................9
1.3.2 活性炭的应用.................................................................................................10
1.4 活性炭负载纳米零价铁（nZVI/AC）................................................................12
1.4.1 nZVI/AC 的性质.............................................................................................12
1.4.2 nZVI/AC 的制备方法.....................................................................................13
1.5 研究意义与内容...................................................................................................14
1.5.1 研究意义.........................................................................................................14
1.5.2 课题研究内容.................................................................................................15
第二章 浸渍法合成材料的影响因素及 HCB 去除.....................................................16
2.1 概述.......................................................................................................................16
2.2 实验材料和方法...................................................................................................17
2.2.1 实验材料.........................................................................................................17
2.2.2 实验方法.........................................................................................................17
(1) 浸渍法合成 nZVI/AC....................................................................................17
(2) nZVI/AC 对HCB 的吸附实验......................................................................18
(3) HCB 的检测...................................................................................................18
(4) 铁负载量的检测............................................................................................18
(5) nZVI/AC 材料表征........................................................................................19
2.3 结果与讨论...........................................................................................................20

2.3.1 铁碳比对 nZVI/AC 材料性质的影响............................................................20
(1) 铁碳比对 nZVI/AC 铁负载量、比表面积和孔体积的影响.......................20
(2) 铁碳比对 nZVI/AC 晶体结构的影响（XRD 分析）..................................20
(3) 铁碳比对 nZVI/AC 形貌的影响（TEM 分析）..........................................21
(4) 铁碳比对合成 nZVI/AC 吸附 HCB 的影响..................................................22
2.3.2 加热时间对 nZVI/AC 性质的影响................................................................24
(1) 加热时间对 nZVI/AC 铁负载量和比表面积的影响...................................24
(3) 加热时间对 nZVI/AC 形貌的影响（TEM 分析）......................................25
(4) 加热时间对合成 nZVI/AC 吸附 HCB 的影响..............................................26
2.4 本章小结...............................................................................................................27
第三章 吸附法合成材料的影响因素及 HCB 去除.....................................................29
3.1 概述.......................................................................................................................29
3.2 实验材料和方法...................................................................................................30
3.2.1 实验材料.........................................................................................................30
3.2.2 实验方法.........................................................................................................30
(1) 吸附法合成 nZVI/AC....................................................................................30
(2) nZVI/AC 对HCB 的吸附实验......................................................................31
(3) HCB 检测.......................................................................................................31
(4) 铁负载量测定................................................................................................31
(5) nZVI/AC 材料表征........................................................................................32
3.3 结果与讨论...........................................................................................................32
3.3.1 铁碳比对 nZVI/AC 的材料性质的影响........................................................32
(1) 铁碳比对 nZVI/AC 铁负载量、比表面积和孔体积的影响.......................32
(2) 铁碳比对 nZVI/AC 晶体结构的影响（XRD 分析）..................................33
(3) 铁碳比对 nZVI/AC 微观形貌的影响（TEM 分析）..................................34
(4) 铁碳比对合成 nZVI/AC 吸附 HCB 的影响..................................................34
3.3.2 乙醇投加量对 nZVI/AC 材料性质的影响....................................................36
(1) 乙醇投加量对 nZVI/AC 铁负载量、比表面积和孔体积的影响...............36
(2) 乙醇投加量对 nZVI/AC 晶体结构的影响（XRD 分析）..........................36
(3) 乙醇投加量对 nZVI/AC 微观形貌的影响（TEM 分析）..........................37
(4) 乙醇投加量对合成 nZVI/AC 吸附 HCB 的影响..........................................38
3.4 本章小结...............................................................................................................39

第四章 比较浸渍法和还原法合成材料 nZVI/AC 去除 HCB 的影响因素及机理....41
4.1 概述.......................................................................................................................41
4.2 实验材料...............................................................................................................42
4.3 实验方法...............................................................................................................42
4.3.1 nZVI 制备.......................................................................................................42
4.3.2 反应时间对 HCB 去除效果的影响...............................................................42
4.3.3 溶液 pH 值对HCB 去除效果的影响............................................................42
4.3.4 水中常见阴阳离子的存在对 HCB 去除效果的影响...................................42
4.4 结果与讨论...........................................................................................................43
4.4.1 反应时间对 HCB 去除效果的影响...............................................................43
4.4.2 溶液的初始 pH 对HCB 去除效果的影响....................................................45
4.4.3 阴离子对 HCB 去除效果的影响...................................................................46
(1) HCO3-的影响..................................................................................................46
(2) Cl-的影响........................................................................................................47
(3) NO3-的影响.....................................................................................................48
(4) SO42-的影响....................................................................................................49
4.4.4 阳离子对 HCB 去除效果的影响...................................................................50
(1) Mg2+的影响....................................................................................................50
(2) Fe2+的影响......................................................................................................51
(3) Cu2+的影响.....................................................................................................52
4.4.5 HCB 降解途径的分析....................................................................................53
4.5 本章小节...............................................................................................................56
第五章 结论与展望.......................................................................................................58
5.1 结论.......................................................................................................................58
5.2 展望.......................................................................................................................59
参考文献.........................................................................................................................60

文档加载中……请稍候！
如果长时间未打开，您也可以点击刷新试试。

下载文档到电脑，查找使用更方便

15 积分 4人已下载

立即下载 VIP免费下载

摘要：

活性炭负载纳米零价铁的合成及对六氯苯的吸附研究摘要六氯苯（HCB）是12种持久性有机污染物之一，具有致癌、致畸和致突变效应，损伤肝脏，造成生长发育停滞，甚至可遗传性。治理含HCB的污染水体对环境保护和人类安全维护有重要意义。活性炭和纳米零价铁（nZVI）应用广泛，并能高效吸附降解有机物，降低或消除其毒性。本研究分别采用浸渍法和还原法合成活性炭负载nZVI（nZVI/AC），确定其最佳合成条件，并探讨该复合材料对以HCB为代表的有机物的去除效果及机理。表征和吸附平衡实验结果表明铁碳质量比、加热时间和乙醇投加量等因素对铁的负载过程有重要影响。活性炭负载纳米零价铁后，其比表面积和孔体积下降，降低程度...

展开>> 收起<<

活性炭负载纳米零价铁的合成及对六氯苯的吸附研究.doc

共80页,预览8页

还剩页未读，继续阅读

活性炭负载纳米零价铁的合成及对六氯苯的吸附研究

相关推荐

开通VIP享超值会员特权

作者详情

相关内容

推荐作者

热门标签

举报选择: