趋磁细菌培养及用于吸附分离贵重金属离子

Cultivation of Magnetotactic Bacteria and Use for Biosorption of Heavy and Precious Metal Ions

摘要:

生物吸附是有效处理含较低浓度重金属离子废水的廉价方法之一。本文通过对污水处理厂活性污泥的富集和培养, 经过分离、纯化活性污泥中的细菌, 最终得到了趋磁细菌MTB-11s。通过16S rDNA鉴定, 菌株MTB-11s属于代尔夫特菌属。对趋磁细菌的生物吸附性能进行了研究, 实验结果表明, 趋磁细菌MTB-11s对不同金属离子具有选择吸附特性, 其对银离子的吸附表现为快速过程, 温度对其吸附性能的影响较小, pH值为4?8时吸附率较高; 随着干菌浓度的增加, 吸附率不断升高, 最终趋于平稳; 随着银离子初始浓度的增加, 吸附率呈现先升高后降低的趋势。在菌量充足或金属离子浓度较低时, 铜、钴离子的存在能促进银离子的吸附, 其他范围则表现为竞争吸附。

Abstract:

Biosorption is one of the high performance and low cost methods for treating wastewater contained low concentration of heavy metal ions. In this paper, the activated sludge from sewage treatment plant was treated by enrichment and cultivation in first step, and then magnetotactic bacteria MTB-11s were obtained by separating and purifying the bacteria obtained in former step. The 16S rDNA analysis showed that the strain of the MTB-11s belonged to Delftia. The results of batch adsorption experiments over magnetotactic bacteria indicated that the magnetotactic bacteria MTB-11s had significant selective adsorption to different metal ions, the adsorption of Ag (I) was a rapid process and almost independence on the temperature. The optimal pH for the adsorption of Ag (I) was 4?8, and the adsorption rate increased with the increase of dry cell concentration and approached to stable finally. With the increase of the initial concentration of Ag (I), the adsorption rate increased to a maxium and then decreased. The Cu (II) or Co (II) coexisted with Ag (I) could promote the adsorption of Ag (I) in the condition of adequate bacteria or low initial concentration of metal ions, otherwise competitive adsorption was found.