利用土壤微生物燃料电池去除土壤重金属的研究

论文总字数：30472字

摘 要

实验分别研究了土壤MFC处理难降解有机物六氯苯（HCB）和重金属铜的情况，简要探究了土壤MFC降解有机物同步产电的特性。并讨论了土壤MFC对五种形态的铜的迁移及去除机制。实验结果如下：

构建了用于去除六氯苯的土壤MFC，在30℃及以乙酸钠（COD浓度为2000mg/kg）作为共基质条件下，在56天实验期内形成4个产电周期，最大产电电压为105mV，电池内阻约为1008Ω。土壤MFC对HCB的去除率为63.36%，高于断路土壤MFC对照系的39.52%及不添加厌氧污泥的断路土壤MFC的29.67%。此差异显示了土壤MFC对土壤中难降解有机污染物HCB的净化效能具有显著促进作用。

在相同条件下构建添加重金属(600mg/kg)作为迁移去除目标的土壤MFC,添加鼠李糖脂脱附铜后运行装置，通过改进BCR法实验测定土壤重金属的迁移水平，发现作为参照组的断路装置并没有发生重金属的迁移，在整个实验土层（100mm）内重金属均明显向阴极迁移，在靠近阳极土层中重金属迁移去除率达到了56.36%,而在阴极，活性炭富集铜浓度为参照组的2.67倍。同时，土壤MFC的阴极明显发生铜的富集作用使铜在阴极得以去除。这证明了土壤MFC可以通过电场显著的对重金属进行迁移、去除。

关键词：土壤微生物燃料电池；生物电化学系统；难降解有机污染物；重金属；产电；净化

A Research on Destruction of Soil Pollutants

using Soil Microbial Fuel Cells

ABSTRACT:In This research，a soil microbial fuel cell (MFC) was constructed to study its property of electro-genisis and degradation of soil pollutants..

The research set Refractory organics (HCB), heavy metal（Copper） nitrate as the targeted pollutant. It explores the MFC soil destruction of refractory organics and its synchronous electro-genesis characteristics. Experiment had been made to make a trial in exploring the soil MFC’s migration and removal mechanisms of five forms of copper. Experimental results are as follows :

We successfully constructed Soil MFC with targeted soil pollutants added hexachlorobenzene. Temperature at 30 ℃ and sodium acetate (COD concentration of 2000 mg/kg) as co-substrates conditions, in a 56-day experimental period to form four electricity production cycle, the largest electricity voltage is 105 mv, battery internal resistance is about 1008 Ω. MFC of refractory organics soil removal rate was 63.36%, higher than the removal rate 39.52% of reference open circuits soil MFC, and the 29.67% of open circuits soil MFC without anaerobic sludge. The differences show the MFC and the anaerobic sludge inoculation obviously promote the purification efficiency for the difficult-to-degrade organic pollutants HCB.

Under the same condition, add copper nitrate with 600 mg/kg as a migration to remove target soil MFC, run the device after adding rhamnose glycolipid stripping copper, the experiment determinates soil water soluble copper level of migration, it shows that heavy metal migration does not happen in the open-curcuits device, the reference group. In the whole experiment soil (100 mm), migration were significantly occurred in the heavy metal to the cathode. Heavy metal migration and removal rate in the anode region is up to 56.36%, and at the cathode, activated carbon enriched in heavy metal concentration is 2.67 times larger than the reference group. At the same time, in the cathode region of soil MFC happens the enrichment of heavy metal ,thus in the cathode we can remove region heavy metal. This illustrates that soil MFC can considerablly migrate and remove heavy metal by means of electric migration .

Key words: Soil microbial fuel cell; Bioelectrochemistry; Refractory organics; Heavy metal; Electrogenesis; Purification

目 录

第一章 绪论 1

1.1 研究背景 1

1.2生物电化学系统基本原理 1

1.2.1微生物的电子传递机制及电极过程 1

1.2.2 MFC对典型污染物去除作用 2

1.3典型土壤污染物及其迁移转化规律 4

1.4研究内容 5

1.4.1研究内容 5

第二章 土壤MFC对难降解有机农药去除的研究 6

2.1材料与方法 6

2.1.1试验装置 6

2.1.2试验仪器、材料及药品 6

2.1.3样品的分析测定方法 7

2.1.4试验方法 8

2.2结果与讨论 9

2.2.1土壤难降解有机污染物污染条件下MFC的产电特性 9

2.2.2难降解有机污染物降解特性 10

2.3小结 13

第三章 土壤MFC对重金属去除的研究 15

3.1材料与方法 15

3.1.1试验装置 15

3.1.2试验仪器、材料及药品 15

3.1.3样品的分析测定方法 15

3.1.4试验方法 15

3.2结果与讨论 16

3.2.1重金属在土壤MFC中的迁移特性 16

3.3小结 18

第四章 结论与展望 19

4.1 研究结论 19

4.2 研究展望 19

致谢 20

参考文献 21

第一章 绪论

1.1 研究背景

土壤是人类赖以生存的要素，也是生态环境的重要组成部分，但土壤污染问题日趋恶化，土壤中的难降解有机物、重金属污染已成为全球性的研究热点^[1-3]。目前针对土壤污染的净化与修复方法主要有物化处理法、微生物净化法，植物修复法等^[4-7]。寻求一种高效、适用性广泛和对土壤生态及结构破坏较小的方法，一直是相关研究的重点内容。

微生物燃料电池（MFC）是一种利用微生物将有机物中的化学能直接转化成电能的装置。其基本工作原理是：在阳极室厌氧环境下，有机物在微生物作用下分解并释放出电子和质子，电子依靠合适的电子传递介体在生物组分和阳极之间进行有效传递，并通过外电路传递到阴极形成电流，而质子通过质子交换膜传递到阴极，氧化剂（一般为氧气）在阴极得到电子被还原与质子结合成水。

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