填充粒子对电化学除氨氮影响机制研究

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填充粒子对电化学除氨氮影响

机制研究

摘要

随着人口增长以及社会经济的快速发展，氨氮排放量日趋增加。 2013 年国家

环境质量公报公布氨氮的排放量已经达到 245.7 万吨/年。氨氮作为一种水体中常

见的污染物，其硝化过程消耗水体中溶解氧为 4.6 g O2/g NH3。研究表明，在水产

养殖过程中，氨对鱼类有一定的毒害作用。此外，作为一种营养元素，氨氮能促

进天然水体中藻类的生长与繁殖，造成水体的富营养化，严重时会形成“水华”

或者“赤潮”。

在现有氨氮的处理技术中，生物法以其处理水量大、成本低等优点占据主要

地位。但是该工艺对温度敏感，冬季低温条件下常不能达到预期效果。此外，工

业废水中某些有毒有机物会影响微生物的硝化过程，造成出水中氨氮超标。随着

国标对氨氮排放要求越来越严格，电化学法以其出水氨氮浓度低、不受温度影响

有毒物质影响小、无剩余污泥、易于自动化控制、主产物氮气环境友好等优点受

到研究者的广泛关注。本文在二维电极电化学氧化法深度去除水中氨氮基础之上

选取不锈钢及 RuO2/Ti 为阴阳两极，研究活性炭与蛭石对电化学除氨氮机理与速

率的影响，在间歇流与连续流两种模式下探讨了极性与非极性两类填充粒子对工

艺过程的影响。

研究结果表明，在间歇流模式下，32.0 mg N/L 氨氮在 300 mg/L 氯离子及中

性条件下，经过 2.0 A 电流电解 2.5 h 后下降到 1.3 mg N/L。同等条件下，填充活

性炭后，30.0 mg N/L 氨氮经过 2.0 h 电解后下降至 0.3 mg N/L，氨氮平均去除速

率高于二维电极。产物分析结果表明，亚硝酸盐为 0.004 mg N/L，硝酸盐为 5.1

mg N/L，总氮为 6.8 mg N/L，产物以气态氮为主。单因素实验结果表明高氯离子

浓度和电流对氨氮去除有利，pH 值对工艺影响比较小。实际废水的处理结果表明，

28.0 mg N/L 氨氮在 300 mg/L 氯离子、2.0 A 电流及中性 pH 值下，经过 2.5 h 电解

后下降至 0.3 mg N/L，同时总氮从 31.5 mg N/L 下降至 6.1 mg N/L，去除率为

80%，可以达到城镇污水排放标准（GB 18918-2002）一级A的要求。

其次，同等间歇流条件下，填充蛭石后，30.0 mg N/L 氨氮经过 1.75 h 电解后

即可下降至 0.1 mg N/L，氨氮平均去除速率比填充活性炭高。产物分析结果表明，

亚硝酸盐为 0.008 mg N/L，硝酸盐为 3.5 mg N/L，总氮为 8.9 mg N/L，产物以气

态氮为主。高氯离子浓度和电流对氨氮去除有利，pH 值对工艺影响比较小。实际

废水的处理结果表明，30.0 mg N/L 氨氮经过 2.0 h 电解后下降至 0.3 mg N/L，同

时总氮从 32.2 mg N/L 下降至 6.3 mg N/L，去除率为 81%，同等条件下氨氮和总氮

去除率均比填充活性炭高。

再者，在连续流模式下，24.4 mg N/L 氨氮在 300 mg/L 氯离子、水力停留时

间10.0 min 及中性条件下，经过 2.0 A 电流电解后出水浓度稳定在 8.9 mg N/L，氨

氮去除率为 64%。同等条件下填充活性炭后，30.0 mg N/L 氨氮电解后出水浓度为

1.4 mg N/L，氨氮去除率比二维电极提高31%。产物分析结果表明，亚硝酸盐为

0.004 mg N/L，硝酸盐为 3.2 mg N/L，总氮为 7.4 mg N/L，产物以气态氮为主。单

因素实验结果表明，增加水力停留时间、氯离子浓度和电流有利于氨氮的去除，

pH 值对氨氮去除影响较小。实际废水的处理结果表明， 28.0 mg N/L 氨氮在 300

mg/L 氯离子、2.0 A 电流及中性 pH 值条件下，经同样水力停留时间电解后出水氨

氮浓度为 0 mg N/L ，同时总氮从 31.5 mg N/L 下降至 3.5 mg N/L ，去除率为

89%，可以达到城镇污水排放标准（GB8978-1996）一级A的要求。

最后研究了同等连续流条件下，填充蛭石对电化学除氨氮过程影响。30.0 mg

N/L 氨氮在水力停留时间为 6.0 min 条件下电解出水浓度为 3.4 mg N/L，达到相似

效果所需处理时间比填充活性炭要低 40%。产物分析结果表明，亚硝酸盐为

0.004 mg N/L，硝酸盐为 4.4 mg N/L，总氮为 11.2 mg N/L，产物以气态氮为主。

单因素实验结果表明，增加水力停留时间、氯离子浓度和电流有利于氨氮的去除

pH 值对氨氮去除影响较小。实际废水的处理结果表明， 30.0 mg N/L 氨氮在 300

mg/L 氯离子、2.0 A 电流及中性 pH 值条件下，经水力停留时间 6.0 min 电解后出

水氨氮浓度为 4.6 mg N/L，同时总氮从 31.3 mg N/L 下降至 8.9 mg N/L，去除率为

72%，达到相似效果所需处理时间比填充活性炭要低 40%。

研究结果表明，在间歇流和连续流两种模式下，电化学方法均可以深度去除

水体中的氨氮，合适条件下出水浓度达到 1 mg N/L 以下。填充活性炭与蛭石两种

粒子可以有效的增强电化学除氨氮的速率，且极性吸附剂蛭石要优于非极性吸附

剂活性炭，达到相似的效果所需水力停留时间更短。这可能是由于蛭石对氨氮的

选择性吸附有效的延长了氨氮在反应器中的停留时间，增强氨氮与电生成活性物

种（如活性氯）的反应几率，加快了氨氮的去除速率。实际废水在间歇流和连续

流两种模式下，经过活性炭/蛭石填充电解反应器电解后均可以达到城镇污水排放

标准一级A的要求。氨氮去除速率要略低于配水，这可能是由于实际废水中的有

机物或还原性物质引起的。

关键词：氨氮电解活性炭蛭石

ABSTRACT

With the rapid growth of population and development of social economy, the

discharge of ammonia is increasing year by year. According to the Chinese

Environmental Quality Bulletin in 2013, the ammonia emission has reached 2,457,000

tons per year. As a common contaminant, the nitrification of ammonia consumes 4.6 g

O2/g NH3 by microorganisms in natural water. Many research shows that ammonia has a

toxic effect on fish in aquaculture industry. Moreover, as a nutrient, ammonia can

promote the growth and propagation of algae, leading to the eutrophication of natural

water bodies. Green or red tide will form in serious situation.

Among all the ammonia removal techniques, biological treatment plays an

important role due to merits such as high treatment capacity, low cost etc. However,

biological process is usually sensitive to temperature, and thus cannot reach the desired

results under cold temperature in winter. Moreover, the toxic components in industrial

wastewater can affect the nitrification process, which leads to the exceeding of

ammonia in the effluent. Since the discharge standard for ammonia is becoming more

and more strict in wastewater, electrochemical method has attracted more and more

attention due to its low ammonia concentration in effluent, less sensitive to temperature

and toxic components, no extra sludge, easy automatic control and environmental

friendly product of nitrogen. Based on previous research on electrolytic removal of

ammonia by conventional two-dimensional electrolysis reactor, this research focused on

the enhanced ammonia removal by using stainless steel as cathode, RuO2/Ti as anode

and activated carbon/vermiculite as packing particle under batch or continuous mode.

Research results showed that under batch mode and neutral pH, 32.0 mg N/L

ammonia with 300 mg/L chloride decreased to 1.3 mg N/L after 2.5 h electrolysis at 2.0

A current. After packing with activated carbon, 30.0 mg N/L can decrease to 0.3 mg

N/L after 2.0 h electrolysis under similar conditions, resulting in a higher ammonia

removal rate. Product analysis revealed that, nitrite, nitrate and total nitrogen were

0.004, 5.1, and 6.8 mg N/L, respectively, which indicated that ammonia was mainly

converted to gaseous nitrogen. High chloride concentration and current were beneficial

for ammonia removal, while pH had little impact by using single factor test. Treatment

of actual wastewater showed that, 28.0 mg N/L ammonia can be reduced to 0.3 mg N/L

after 2.5 h electrolysis under the conditions of 300 mg/L chloride, 2.0 A current and

neutral pH. Total nitrogen decreased from 31.5 mg N/L to 6.1 mg N/L, which can reach

the level 1 grade A discharge standard of municipal wastewater.

Similarly, when packing with vermiculite, 30.0 mg N/L can decrease to 0.1 mg

N/L after 1.75 h electrolysis under similar conditions, resulting in a higher ammonia

removal rate than packing with activated carbon. Product analysis revealed that, nitrite,

nitrate and total nitrogen were 0.008, 3.5, and 8.9 mg N/L, respectively, which indicated

that ammonia was mainly converted to gaseous nitrogen. High chloride concentration

and current were beneficial for ammonia removal, while pH had little impact by using

single factor test. Treatment of actual wastewater showed that, 30.0 mg N/L ammonia

can be reduced to 0.3 mg N/L after 2.0 h electrolysis under the conditions of 300 mg/L

chloride, 2.0 A current and neutral pH. Total nitrogen decreased from 32.2 mg N/L to

6.3 mg N/L. Enhanced removal of both ammonia and total nitrogen was observed than

packing with activated carbon.

Under continuous mode with 300 mg/L chloride, 24.4 mg N/L ammonia can be

reduced to 8.9 mg N/L at a current of 2.0 A and hydraulic retention time of 10.0 min by

using conventional two dimensional electrode. After packing with activated carbon,

30.0 mg N/L ammonia can be reduced to 1.4 mg N/L under similar conditions, leading

to a higher ammonia removal. Product analysis revealed that, nitrite, nitrate and total

nitrogen were 0.004, 3.2, and 7.4 mg N/L, respectively, which indicated that ammonia

was mainly converted to gaseous nitrogen. Single factor experiments shows that longer

HRT, higher chloride concentration and current were beneficial for ammonia removal,

and pH had little effect. Treatment of actual wastewater revealed that 28.0 mg N/L

ammonia can be reduced to 0 mg N/L, together with a removal of total nitrogen from

31.5 mg N/L to 3.5 mg N/L which can reach the level 1 grade A discharge standard of

municipal wastewater.

Finally, electrolysis were performed by packing with vermiculite under continuous

mode. 30.0 mg N/L ammonia can be reduced to 3.4 mg N/L under similar conditions

with a HRT of 6.0 min, which indicated 40% less time were required compared with

activated carbon. Product analysis revealed that, nitrite, nitrate and total nitrogen were

0.004, 4.4, and 11.2 mg N/L, respectively, which indicated that ammonia was mainly

converted to gaseous nitrogen. Single factor experiments shows that longer HRT, higher

chloride concentration and current were beneficial for ammonia removal, and pH had

little effect. Treatment of actual wastewater revealed that 30.0 mg N/L ammonia can be

reduced to 4.6 mg N/L, together with a removal of total nitrogen from 31.3 mg N/L to

8.9 mg N/L. Similarly, 40% less time were required to reach similar treatment effect by

packing vermiculite.

Research results showed that electrochemical method can deeply remove ammonia

to less than 1 mg N/L under both batch and continuous mode. Enhanced removal of

ammonia was observed by packing with activated carbon or vermiculite. Vermiculite

was better than activated carbon due to its adsorption for ammonia, which can increase

the ammonia retention time in the electrolysis reactor, and thus accelerate the reaction

between ammonia and electro-generated activated species (such as active chlorine).

Treatment of actual wastewater under batch and continuous mode showed that ammonia

can be reduced to less that level 1 grade A standard for discharge of municipal

wastewater under suitable conditions. The ammonia removal rate was lower than

synthetic wastewater, which might be caused by the organics or other reducing matters

in municipal wastewater.

Key Word: ammonia, electrolysis, activated carbon, vermiculite

目 录
摘  要
ABSTRACT
第一章 绪 论...................................................................................................................1
1 研究背景.................................................................................................................1
1.1 氨氮的来源及危害...........................................................................................1
1.2 深度降解氨氮的意义.......................................................................................2
2 国内外研究现状.....................................................................................................2
2.1 生物法...............................................................................................................2
2.2 氨吹脱汽提法...................................................................................................3
2.3 离子交换法.......................................................................................................4
2.4 折点加氯法.......................................................................................................5
2.5 电化学氧化法...................................................................................................5
3 电化学氧化概述.....................................................................................................6
3.1 电化学方法原理...............................................................................................6
3.2 二维电化学氧化法研究现状...........................................................................7
3.3 三维电化学氧化法研究现状...........................................................................8
3.4 电极材料的确定...............................................................................................9
4 课题研究的意义与内容.......................................................................................11
4.1 研究目的.........................................................................................................11
4.2 研究意义.........................................................................................................11
4.3 研究内容.........................................................................................................12
第二章 材料与方法.......................................................................................................13
1 实验装置...............................................................................................................13
1.1 间歇流实验装置.............................................................................................13
1.2 连续流实验装置.............................................................................................13
2 实验试剂及材料...................................................................................................14
3 实验仪器...............................................................................................................14
4 实验方法...............................................................................................................14
5 计算方法...............................................................................................................15
第三章 连续流条件下填充活性炭对电化学去除氨氮影响研究...............................16
1 与未填充粒子对氨氮处理效果比较...................................................................16
2 氨氮去除机理研究...............................................................................................16

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摘要：

填充粒子对电化学除氨氮影响机制研究摘要随着人口增长以及社会经济的快速发展，氨氮排放量日趋增加。2013年国家环境质量公报公布氨氮的排放量已经达到245.7万吨/年。氨氮作为一种水体中常见的污染物，其硝化过程消耗水体中溶解氧为4.6gO2/gNH3。研究表明，在水产养殖过程中，氨对鱼类有一定的毒害作用。此外，作为一种营养元素，氨氮能促进天然水体中藻类的生长与繁殖，造成水体的富营养化，严重时会形成“水华”或者“赤潮”。在现有氨氮的处理技术中，生物法以其处理水量大、成本低等优点占据主要地位。但是该工艺对温度敏感，冬季低温条件下常不能达到预期效果。此外，工业废水中某些有毒有机物会影响微生物的硝化过程，...

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