【作者】 孙辉；

【导师】 刘冬梅；

【作者基本信息】 哈尔滨工业大学 ， 环境工程（专业学位）， 2017， 硕士

【摘要】 随着近几十年社会经济的快速发展,环境问题受到了人们的关注,特别是近几年来,中央加大了对环境保护的力度。各种修复水体污染的方法被研制出来,其中利用藻类等生物修复水体重金属污染或者利用藻类生物吸附剂处理污水是一种具有广泛应用前景的技术。小球藻等绿藻广泛存在于水体中,并且生长繁殖速度快,很容易进行大规模养殖,同时对重金属具有一定的吸附能力,可以有效降低重金属的含量。但是,重金属对生活藻类的毒性作用影响了其的正常生长,在一定程度上抑制了藻类在水处理中的应用。同时,在重金属的胁迫下,藻细胞自身能够通过一系列生理活动来减轻重金属的毒害作用,这一特点对于活性藻体在重金属水体中的应用具有重要的实际意义。另外,死亡的藻体对重金属同样有一定的吸附能力。本研究采用静态实验的方法,选用水体中常见的绿藻(小球藻、斜生栅藻),对其毒理学进行研究。获得了Cd2+对两种藻的半数抑制浓度分别为5.94mg/L、4.13 mg/L。同时对不同镉胁迫下的小球藻和斜生栅藻的叶绿素a,胞内胞外可溶性糖和蛋白质的浓度变化进行了比较,获取了两种藻类对Cd2+的耐受性程度,结果显示小球藻对镉的耐受性更好。另外,镉的胁迫下,小球藻藻细胞本身的抗氧化酶发生了一系列的变化,如SOD随着镉浓度先升高后降低等,说明在此过程中,抗氧化酶确实起到了一定的解毒效果。在吸附实验中,研究了初始藻细胞密度,初始重金属浓度,酸碱性,以及温度对生活、死亡小球藻生物吸附效率的影响,结果显示小球藻对镉具有很好的吸附效能,且生活小球藻的吸附效率要高于死亡小球藻。同时采用批量平衡法研究了小球藻对镉的吸附动力学与热力学,并采用伪一级动力学方程、伪二级动力学方程、Langmuir等温线方程以及Freundlich等温线方程对实验数据进行了拟合。结果显示:在溶液中性偏酸性的条件下,吸附效果最好,在20-30℃温度范围内提高温度有利于吸附的发生,同时,藻的生物量及镉的初始浓度都在一定程度上影响到吸附效果。伪二级动力学方程、Langmuir等温线方程以及Freundlich等温线方程都可描述小球藻生物吸附镉的过程。通过红外光谱分析,发现了小球藻在吸附过程中是C-O、C=O、-COOH、-NH-等官能团发挥了重要的作用。更多还原

【Abstract】 With the rapid development of social economy in recent decades,environmental problems have attracted people’s attention,especially in recent years,the central government has increased the intensity of environmental protection.Various methods of remediation of water pollution have been developed,and the use of algae and other bioremediation of water heavy metal pollution or the use of biosorbent treatment of sewage is a widely used technology.Chlorella and other green algae widely exist in water bodies,and grow rapidly.They are easy to carry out large-scale breeding,and have a certain adsorption capacity of heavy metals,which can effectively reduce the content of heavy metals.However,the toxic effects of heavy metals on living algae affect their normal growth and,to some extent,inhibit the application of algae in water treatment.At the same time,under heavy metals stress,toxic algal cells can reduce heavy metals through a series of physiological activities,which has important practical significance for the application of the activity of algae in the heavy metal in the water.In addition,the dead algae also have a certain adsorption capacity for heavy metals.In this study,the method of static experiment was used to study the toxicology of common green algae(Chlorella vulgaris and Scenedesmus obliquus)in water.The inhibitory concentrations of Cd(II)on the two algae were 5.94 mg/L and 4.13mg/L,respectively.At the same time,under different Cadmium Stress,the Chlorella and Scenedesmus’ s chlorophyll a concentration;changes of extracellular soluble sugar and protein in cells were compared,and obtained two kinds of algae on Cd(II)tolerance,which showed better tolerance to cadmium in chlorella.In the adsorption experiment,the effects of different initial algal cell density,different initial heavy metal concentration,different acidity and alkalinity,and different temperature on the biosorption efficiency of live and killed Chlorella vulgaris were studied.The results showed that Chlorella had a good effect on cadmium And the adsorption efficiency of Chlorella vulgaris is higher than that of Chlorella.At the same time,the adsorption kinetics and thermodynamics of cadmium on chlorella were studied by batch balance method.The experimental data were analyzed by pseudo-first order kinetic equation,pseudo quadratic kinetic equation,Langmuir isotherm equation and Freundlich isotherm equation Together The results showed that the adsorption effect was the best under the condition of neutral acidity of solution,and the increase of temperature in a certain range was beneficial to the occurrence of adsorption.The biomass of algae and the initial concentration of cadmium all affected the adsorption effect to a certain extent.Pseudo-second-order kinetics equation,Langmuir isotherm equation and Freundlich isotherm equation can describe the process of adsorption from different aspects.The main functions of chlorella in this process are the functional groups such as C-O,C=O,-COOH and-NH-by infrared spectroscopy.更多还原