EHEHPA萃取Co(II)的动力学和机理的研究
文献类型：学位论文
| 作者 | 陈长庆 |
| 学位类别 | 硕士 |
| 答辩日期 | 1986-06-30 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 陈家镛 |
| 中文摘要 | 本工作研究了2－乙基已基膦酸单2－乙基已基酯（即P507）从醋酸醋酸钠缓冲介质中萃取Co(II)的动力学和机理。萃取反应在改进的恒界面池中进行，并建立了连续、自动测量萃取动力学数据的实验体系。在动力学坪区测定了一系列初始萃取速率和反萃速率：比界面积和表面活性剂对萃取速率的影响表明化学反应发生在液液界面；低于30℃时的表观活化能为82 kJ mol~(-1)，高于30℃时为31 KJ mol~(-1)，组分浓度的大幅度变化也会引起传质控制过程的转变，由此可以认为：EHEHPA萃取Co(II)的动力学过程在萃取速率较低时为化学反应控制，随着反应速率的加快转变为组分在界面膜的扩散控制。在假定萃取剂界面吸附浓度不同于界面膜扩散浓度的前提下，提出了下列反应机理：(HA)i <-> (HA)ad (1) (HA)ad + (M)i <-> (MA)i + (H)i (2) (MA)i + (HA)i <-> (MA_2)i + (H)i (3) 其中（1）为萃取利剂界面吸附快速平衡过程，结合组分在界面膜的稳态扩散，推导得到的动力学模型，能够比较满意，合理地解释整个萃取过程。 |
| 英文摘要 | The Kinetics and mechanism of cobalt(II) extraction with 2-ethylhexyl-phosphoric acid mono-2-ethylhexyl ester(HA) in n-hexane from acetic acid-sodium acetate baffle solutions has been investigated in an improved Lewis type cell. A new technique has been developed in which metal concentrations in organic phase can be measured continuously by a flow cell in a double beam spectrophotometer and the output signal is transfered into a microcomputer through an AD-DA converter to collect experimental data. The experiments were carried out at the plateau region of the curve of extraction rates vs. stirring speeds. The effects of the special area and surfactant on the initial extraction rates showed that the chemical reaction may occur at the interface. The apparent activty energy is respectively 82 KJ mol~(-1) and 31 KJ mol~(-1) at the temperature higher and loweer then 30 ℃. It was also found that changing the species concentrations the extraction processes can shift from reaction regime to diffusion regime. It was presumed that extractant concentraction adsorbed at interface is different from at the stagnant diffusion films and a mechanism has been put forward: (HA)i = (HA)ad (1) (HA)ad + (M)i = (MA)i + (H)i (2) (MA)i + (HA)i = (MA2)I + (H)i (3) where (1) is the fast adsorbion equilibrium. Correlating with those species diffusion in above equations at the interfacial films, a mathematical model was developed and fitted the experimental results quite well. |
| 语种 | 中文 |
| 公开日期 | 2013-09-27 |
| 页码 | 79 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/2052]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 陈长庆. EHEHPA萃取Co(II)的动力学和机理的研究[D]. 中国科学院研究生院. 1986. |
入库方式： OAI收割
来源：过程工程研究所
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