多孔材料与微生物结合去除废水中重金属的研究

发布时间：2018-01-04 01:16

本文关键词：多孔材料与微生物结合去除废水中重金属的研究　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国工业的快速发展,重金属污染的速度已日趋加重。如重金属镉、汞、铅等具有较强的生物毒性,而这些重金属在正常环境下较为稳定,短时间内难以被降解。这些重金属能长期蓄积在生物体内,不易排出可通过食物链对人体健康造成更大的潜在危害。因此,如何有效的处理工业重金属污染废水已成为环境工程领域一个亟需解决的问题。在全面综述生物吸附材料在吸附重金属的理论和技术基础上,本文对多孔材料和酵母工程菌在吸附和联合吸附镉、汞、铅等重金属离子的能力进行多组研究。首先用多孔材料活性炭、天然沸石、蒙脱石来分别对含不同浓度的镉、铅、汞重金属废水进行吸附试验,通过对吸附结果进行分析发现：活性炭对汞的吸附效果最好,天然沸石对铅的吸附效果最好,蒙脱石对镉的吸附效果最好,并确定在试验浓度范围内,多孔材料对镉、铅、汞离子的吸附都能符合Langmuir和Freundlich等温吸附方程式,吸附拟合性很好。其次,本试验选用对重金属具有较强吸附能力的酵母工程菌,通过试验确定出酵母工程菌对镉、铅、汞重金属混合废水的吸附的最佳条件参数：初始pH值、吸附时间、重金属离子初始浓度、酵母工程菌用量等。实验结果表明：pH值为4.0时对镉、铅、汞重金属离子的去除效果最佳,在30分钟左右均达到吸附平衡状态；酵母工程菌在用量为4g时对重金属废水的吸附效果最佳。且酵母工程菌的吸附过程符合准二级动力学模式,有很好的拟合效果。由于游离的菌种处理重金属废水的稳定性较差,且处理周期较短、效果并不理想,因此,本文运用固定化微生物技术,将酵母工程菌与多孔材料结合共同处理含镉、铅、汞的重金属废水。试验以后,我们发现蒙脱石与酵母工程菌结合去除废水中重金属的效果最佳,对汞和铅的去除效率可达到95%以上。比单独运用多孔材料吸附和酵母工程菌去除重金属的效率提高了很多。并用准二级动力学模式对联合吸附过程进行分析,建立了准二级动力学模型,经验证在一定时间范围内,此模型能够满足蒙脱石与酵母工程菌结合去除重金属废水的模拟预测要求。
[Abstract]:With the rapid development of industry in China, the pollution rate of heavy metals has become increasingly serious, such as cadmium, mercury, lead and other heavy metals have strong biological toxicity, and these heavy metals in the normal environment is more stable. These heavy metals can be accumulated in organisms for a long time and can not easily be excreted through the food chain to cause greater potential harm to human health. How to effectively treat industrial heavy metal polluted wastewater has become an urgent problem in the field of environmental engineering. On the basis of a comprehensive review of the theory and technology of adsorption of heavy metals by biosorption materials. In this paper, the ability of porous materials and yeast engineering bacteria to adsorb cadmium, mercury, lead and other heavy metal ions was studied. Firstly, activated carbon and natural zeolite were used as porous materials. Montmorillonite respectively contains different concentrations of cadmium, lead, mercury heavy metal wastewater adsorption experiments, through the analysis of adsorption results found: activated carbon adsorption of mercury is the best. The adsorption effect of natural zeolite to lead is the best, and that of montmorillonite to cadmium is the best, and it is determined that the porous material can adsorb cadmium and lead in the range of experimental concentration. The adsorption of mercury ions can accord with the isothermal adsorption equations of Langmuir and Freundlich, and the adsorption fit is very good. Secondly. In this experiment, yeast engineering bacteria with strong adsorption capacity for heavy metals were selected, and the optimal conditions for the adsorption of cadmium, lead and mercury heavy metal wastewater by yeast engineering bacteria were determined: initial pH value. The adsorption time, the initial concentration of heavy metal ions, the amount of yeast engineering bacteria and so on. The experimental results show that the removal efficiency of cadmium, lead and mercury heavy metal ions is the best when the pH value is 4.0. The adsorption equilibrium was reached at about 30 minutes. The adsorption effect of yeast engineering bacteria on heavy metal wastewater was the best when the dosage was 4 g, and the adsorption process of yeast engineering bacteria was in accordance with the quasi-second-order kinetic model. Because the stability of the free bacteria treatment of heavy metal wastewater is poor, and the treatment period is short, the effect is not ideal, so the immobilized microorganism technology is used in this paper. Yeast engineering bacteria combined with porous materials to treat heavy metal wastewater containing cadmium lead mercury. After the experiment we found that montmorillonite combined with yeast engineering bacteria removal of heavy metals in wastewater is the best. The removal efficiency of mercury and lead can reach more than 95%, which is much higher than that of using porous materials alone and yeast engineering bacteria to remove heavy metals. The combined adsorption process is analyzed by quasi-second-order kinetic model. . A quasi-second-order kinetic model was established. It was proved that the model could meet the requirements of simulation and prediction of montmorillonite combined with yeast engineering bacteria in the removal of heavy metal wastewater.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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