【作者】 武振华；

【导师】 孙津生；

【作者基本信息】 天津大学 ， 化学工程， 2007， 硕士

【摘要】 随着电子、信息和化工等领域的快速发展,贵金属的应用愈来愈广泛,其使用量逐年大幅度增加,含贵金属的废料量也随之快速增加。因此从废弃物中回收贵金属的研究具有深远的经济和社会效益。为了探索贵金属离子的生物吸附机理及其选择性富集机理,并为下一步从富集生物载体中回收贵金属打下基础,本文采用磁场-趋磁细菌复合工艺,对趋磁细菌处理含贵金属离子废液进行了深入研究。在研究过程中本文首次采用了两级复合工艺组合的形式对二元金属离子体系的竞争吸附进行了初步研究,为日后普通金属离子循环强化吸附贵金属离子工艺过程的开发和研究提供部分实验研究储备。研究过程中先对从污水处理厂取回的活性污泥按照趋磁细菌的培养基进行富集培养,再通过趋磁收集器收集,经实验验证收集到的菌中94.7%为趋磁细菌。利用所得到的趋磁细菌,对单一贵金属离子吸附过程进行了详细的实验研究。确定了趋磁细菌对Pd²⁺、Au³⁺、Pt⁴⁺、Ag⁺四种贵金属离子的最佳吸附条件,包括温度、pH值、菌量、初始贵金属离子浓度及吸附时间等。另外,研究表明各吸附过程均遵循准一级动力学方程和Langmuir吸附等温模型。在对趋磁细菌吸附单一贵金属离子过程的研究基础上,对Pd-Al、Au-Cu和Au-Cu-Ni多元贵金属离子体系进行了实验研究。研究结果表明,趋磁细菌对贵金属离子的吸附量远大于对其它普通金属离子的吸附量,说明在多元体系中,趋磁细菌对贵金属离子有良好的选择吸附性。在静态分离实验中,利用多悬丝分离器,主要考察了不同磁场强度和不同时间对分离过程的影响,研究表明,磁场强度越大,分离时间越长,对吸附了贵金属离子的趋磁细菌的分离效果越好。最后根据此前得到的最佳操作条件,应用复合工艺流程连续处理含贵金属离子废液。通过二次吸附、二次分离工艺,在实现分离器出水达到排放标准的同时,逐级分离出贵金属离子及普通金属离子,可对分离出的菌体作进一步金属回收处理。更多还原

【Abstract】 With the fast development of electronic engineering, information industry and chemical engineering, the scope and amount of precious metal employment are found expanding yearly. The risk pollution from waste materials of precious metals are uproaring as the result of the situation mentioned.As a try to remove and enrich the precious metals, lab research is performed, aiming at the theories of adsorption and its selectivity, which is also the first step of precious recovery. In this dissertation, a novel comprehensive technology is adopted, which involves magnetic field-magnetotactic bacteria system. The treatment is discussed and probed in detail, in which the precious metal ions in waste liquid can be adsorbed and then removed in magnetic field by magnetotactic bacteria, the carrier. During the research, a double stage flowsheet of the upper mention technology is put to use for the first time. In this flowsheet, competitive adsorption of double metal system is observed, which gives firsthand data supporting the consequent research of novel recycling normal metal reinforced process.In the research, the activated sludge taken from the wastewater treatment plant is cultivated in culture medium for magnetotactic bacteria. Then the bacteria are collected in magnetic field utilizing their direction finding feature. The result indicates that 94.7% of the collected are magnetotactic bacteria. Then, adsorption of single precious metal ion is probed in detail. The optimum adsorption conditions for the precious metal ions: Pd²⁺, Au³⁺, Pt⁴⁺, Ag⁺, such as pH, temperature, biomass concentration, initial concentration of precious metal ions and time, are confirmed.Math work finds that the adsorption process in accordance with the pseudo-first order kinetic model and Langmuir isotherm.Based on the above work, the adsorption of Pd-Al、Au-Cu、Au-Cu-Ni is studied. The result indicates that the magnetotactic bacteria have the property of selective adsorption. The adsorption quantity of magnetotactic bacteria on precious metal ions is much higher than that of co-exist counterparts.Separation of magnetotactic bacteria carrying precious metal ions from waste liquid is studied using separator with paralleled wires. The result indicates that the higher magnetic field strength and the longer duration, the better separation effect. At last, the waste liquid with precious metal ions is treated by the magnetic field-magnetotactic bacteria comprehensive technology continuously under the optimum operation condition. Through two adsorption and two separation processes, precious metal ions and other metal ions are separated in sequence. Simultaneously, the liquid is purified.更多还原