| 摘要 | 锑(Sb) 是一种典型的有毒有害重金属元素,在地壳中的含量很低, 但Sb矿石自然风化和采矿、冶炼、化石燃料的燃烧以及Sb化合物的广泛使用,增加了环境中Sb的含量,对大气、水体、土壤等造成了不同程度的Sb污染。Sb及其化合物通过食物链、呼吸、皮肤接触等方式进入体内并对人体产生毒害。在重金属废水的处理中除采用传统物理化学方法外，生物方法逐渐被引入重金属废水处理领域，在生物方法中，硫酸还原菌（SRB）的研究很多，但是运用SRB处理含Sb废水的研究很少。本文在分离SRB基础上,对SRB去除Sb废水的主要影响因素进行了初步研究,旨在发展新的Sb废水处理方法。 本文从阿哈湖支流淤泥中, 通过富集分离，筛选得到一株具有硫酸盐还原功能菌株SRB1，经形态学以及16SrDNA基因序列分析，初步鉴定菌株SRB1为梭菌属细菌（Clostridium sp）。对菌株 SRB1 生长特性进行了研究，菌株在20-40℃都能较好生长，最佳温度为35 ℃，属于中温菌。最佳生长 pH 为 7.0，当 pH 范围为 5.0-9.0 时，菌株都能较好的生长。 开展了SRB1对废水中Sb去除实验，研究不同pH、温度及初始Sb浓度对Sb去除的影响和不同实验时间内各因子（Sb、SO42-、H2S、pH、Eh及光密度OD）的动态变化情况。实验表明，利用硫酸盐还原菌去除水中的Sb是可行有效的，处理的最佳pH范围为6.0-7.0，最佳温度范围为30-35℃，在这一条件下对废水中Sb的去除可以达到90%以上。 SRB1异化硫酸根生成的H2S使Sb(V)还原为Sb(Ⅲ)，Sb(Ⅲ)与溶液中生成的H2S反应生成不溶于水的沉淀，结合SEM-EDS分析沉淀为Sb2S3，对Sb的去除贡献占到80%以上。另外， SRB1的死菌体对 Sb去除有积极作用，研究发现，相对于不加菌空白，死菌体细胞对溶液中 Sb(V) 的去除率为 33.3%；在相同浓度下，死菌体细胞对Sb(Ⅲ)的去除率为 13.3%。从而说明，形成硫化物沉淀是去除Sb的主要机制，同时死菌吸附对去除也有少量贡献。 溶液中Sb去除的基本过程可以概述为：随着SRB1繁殖， SO42-被还原为H2S， Sb(V)在H2S作用下先被还原为Sb(Ⅲ)， Sb(Ⅲ)再与H2S反应生成Sb2S3沉淀，使得溶液中的Sb被去除。 总之，通过采用SRB1对废水中Sb进行去除实验，研究不同pH、温度及初始Sb浓度对Sb去除的影响和不同实验时间内各因子（Sb、SO42-、H2S、pH、Eh及光密度OD）的动态变化情况，得到了最佳去除条件，为含Sb废水的治理提供了理论依据。 |
| 其他摘要 | Sb is a typical heavy element with high toxicity, Sb concentration in surface is low, but Sb and its compounds occur widely in the atmosphere, soil, water because of natural processes and human activities, and lead to increasing contamination of Sb. Sb and its compounds are toxic to human mainly through the food cycle, breathe and occupational exposure. Except for traditional physical-chemical technologies, the removal process of metals in wastewater by biological methods is gradually using , and sulfate-reducing bacteria is a popular technology. Based on purified bacteria, the effect of factors on the removal of Sb in wastewater by sulfate-reducing bacteria were evaluated, and result in a new method of removal of Sb. An anaerobic strain SRB1 which able to use sulfate as an electron acceptor and to form hydrogen sulfide was obtained. After the identifying of morphological and 16SrDNA show that the strain may belongs to Clostridium sp. Growth of SRB1 was fastest at 35℃and rapid at 20~40℃; The optimal pH was 7.0, which SRB1 could live ranging from 5.0 to 9.0. The removal of Sb in wastewater by sulfate-reducing bacteria was conducted. The effect of pH, temperature and the initial Sb concentration as well as the evolution of the reaction were evaluated. The results showed that the optimal pH range was 6.0~7.0,the optimal temperature was 30~35℃.The removal of Sb was more than 90%. Sb reacted with H2S and precipitated as Sb2S3 , and the removal of Sb was more than 80%, the precipitations created by SRB1 was conducted by SEM-EDS. In addition, dead SRB1 thalli may play a positive role in the removal of Sb in wastewater. The research result show that the removal of Sb(Ⅴ) and Sb(Ⅲ) was respectively 33.3% and 13.3% caused by the dead thalli compared with the control. Meanwhile, the result show that the sulfide precipitations was the main removal mechanism , and dead SRB1 thalli had a few contribution.The main reason of the produce of Sb(Ⅲ) is H2S. The removal mechanism of Sb in wastewater by SRB1 is as fellow:In the reaction, SO42- was reduced to H2S, resulting the decrease of SO42-. In the meantime, the initial Sb in wastewater was Sb(Ⅴ) ,Sb(Ⅴ) was reduced to Sb(Ⅲ) ,which reacted with H2S and precipitated as Sb2S3.This mechanism resulted in the removal of Sb in wastewater. In conclusion, the removal of Sb in wastewater by sulfate-reducing bacteria was conducted. The effect of pH, temperature and the initial Sb concentration as well as the evolution of the reaction were evaluated,and had the best factors of the removal of Sb that provide a theoretical basis of the removal of Sb. Key words: sulfate-reducing bacteria; wastewater; Sb; removal |
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