【作者】 彭慧；

【导师】 刘云国；

【作者基本信息】 湖南大学 ， 环境工程， 2007， 硕士

【摘要】 水环境的重金属污染已经成为一个全球性的环境问题。从工业废水中去除有毒的重金属元素是环境保护领域中的难题之一。传统的重金属废水处理技术包括稀释换水法、化学沉淀法、电解法、离子交换法等,这些方法在遇到含重金属废水的处理量大且重金属浓度低的情况时,就会暴露成本高、效果差的缺点。用生物吸附技术吸附重金属离子是一项新的处理技术,能有效的去除和回收溶液中的重金属。本文通过分批式实验方法对非活性浮游颤藻（Oscillatoria planctonica）吸附Cu²⁺和Zn²⁺的吸附特性进行研究,并研究pH值、吸附剂与溶液的固液比、初始重金属离子浓度、温度和反应接触时间对吸附的作用。非活性浮游颤藻的吸附容量随溶液pH值的改变而变化,在pH=2的时候,对Cu²⁺和Zn²⁺吸附量均非常小,pH值从2上升到4时,吸附量急剧增加,pH=4～5.5之间,吸附量有渐渐平衡的趋势。吸附反应温度对吸附反应没有明显的影响。随着吸附剂与溶液固液比的升高,吸附剂的单位吸附量反而减少,但是Cu²⁺和Zn²⁺的去除率却随之上升,非活性颤藻的最大去除率分别达到79.62%和65.60%。随着重金属离子Cu²⁺和Zn²⁺初始浓度的增加,非活性颤藻的单位吸附量也增加,最后渐渐趋向平衡。Cu²⁺和Zn²⁺的等温吸附平衡均能用Langmuir等温吸附线和Freundlich等温吸附线来描述,拟合相关系数均在0.9以上,且Freundlich模型对吸附的拟合效果更好。实验表明,吸附反应的速度很快,在反应40分钟左右吸附量就达到了平衡吸附量的80%～90%,吸附反应1小时左右就基本达到了平衡,二级动力学方程对实验数据的拟合相关度非常好。0.1 mol/L的硝酸溶液能有效的将吸附在非活性浮游颤藻上的Cu²⁺和Zn²⁺解吸下来。为了提高非活性浮游颤藻（Oscillatoria planctonica）的吸附能力,本文还研究了预处理对浮游颤藻吸附Cu²⁺和Zn²⁺的作用,以及环境因素对预处理藻粉吸附Cu²⁺和Zn²⁺的影响。用0.2 mol/L的CaCl2对浮游颤藻进行的预处理能提高其对Cu²⁺和Zn²⁺的生物吸附量,经预处理的藻粉对Cu²⁺的理论最大吸附量为73.53 mg/g,对Zn²⁺的理论最大吸附量为59.52 mg/g。环境因素对预处理藻粉吸附Cu²⁺和Zn²⁺的影响与其对非活性浮游颤藻吸附的作用相似。红外光谱分析表明预处理藻粉对Cu²⁺和Zn²⁺的生物吸附机理主要归结于重金属离子与—OH、—CH2—和酰胺基的结合作用。更多还原

【Abstract】 Contamination of the aquatic environment by heavy metals has already become a worldwide environmental problem. The removal of toxic heavy metals from industrial wastewaters is one of the most important environmental issues. The conventional heavy metal treatment technologies such as dilute and exchange, chemical precipitaion, electrolytic technologies and ion-exchange, can be less effective and more expensive when situations involving high volumes and low metal concentrations are encountered. Biosorption of heavy metals ions is a relatively new technology, which is an effective process for the removal and recovery of heavy metal ions from aqueous solution.In this paper, the adsorption properties of nonliving Oscillatoria planctonica for Cu²⁺ and Zn²⁺ were investigated using the batch method as a function of pH, biosorbent to solution ratio, initial heavy metal ion concentration, temperature, and contact time. The biosorption capacities were solution pH dependent. At pH less than 2, the amount of biosorption was almost negligible for both Cu²⁺ and Zn²⁺, within the pH range of 2⁴, the biosorption capacity increased rapidly, and in the pH range of 4⁵.5, tended to a maximum value. But the biosorption wasn’t affected by temperature. The adsorption capacity decreased with increasing the biosorbent to solution ratio, while the removal ratios of Cu²⁺ and Zn²⁺ increased and the maximum removal ratios of nonliving Oscillatoria planctonica were 79.62% and 65.60% respectively. The sorption of Cu²⁺ or Zn²⁺ increased as the initial concentration increased. The adsorption equilibriums of Cu²⁺ and Zn²⁺ could be represented by Langmuir isotherms and Freundlich isotherms, R2>0.9. However, the Freundlich model exhibited a slightly better fit to the biosorption data than the Langmuir model. The biosorption kinetics was found to be fast, about 80%～90% of the total adsorbed heavy metal ions were removed from the solution within 40 min of agitation, and equilibrium reached in about 1 hour. Pseudo second-order described the sorption data very well. The adsorbed Cu²⁺ and Zn²⁺ could be desorbed effectively by 0.1 mol/L nitric acid.In order to enhance the adsorption capacity, the effects of pretreatment and environmental factors on biosorption of Cu²⁺ and Zn²⁺ were studied. The pre-treatment by 0.2 mol/L CaCl2 enhanced both Cu²⁺ and Zn²⁺ biosorption, the theoretic maximum capacity of pre-treated biomass was 73.53 mg/g for Cu²⁺ and 59.52 mg/g for Zn²⁺. The effects of environmental factors on Cu²⁺ and Zn²⁺ biosorption by pretreatment biomass were similar to the effects on the biosorption by nonliving biomass. The FTIR analysis showed that the mechanism involved in biosorption of Cu²⁺ and Zn²⁺ by pretreatment Oscillatoria planctonica was mainly attributed to binding of—OH,—CH2—and amide I.更多还原