疏水性离子液体为溶剂对Co^(2+)和Cd^(2+)废水的萃取性能  

Extraction of Co^(2+) and Cd^(2+) from Wastewater Using Hydrophobic Ionic Liquids as Solvents

作　　者：李长平[1] 辛宝平[2] 徐文国[1] 朱庆荣[2] 卢士香[1] 

机构地区：[1]北京理工大学理学院,北京100081 [2]北京理工大学化工与环境学院,北京100081

出　　处：《过程工程学报》2007年第4期674-678,共5页The Chinese Journal of Process Engineering

基　　金：国家自然科学基金资助项目(编号:20307002)

摘　　要：研究了疏水性离子液体[Bmim]PF6(1-丁基-3-甲基咪唑六氟磷酸盐)、[Hmim]PF6(1-己基-3-甲基咪唑六氟磷酸盐)和[Omim]PF6(1-辛基-3-甲基咪唑六氟磷酸盐)对Co2+和Cd2+的萃取性能.结果表明,未加入螯合剂时,离子液体对Co2+和Cd2+的萃取率都很低.螯合剂的加入大大提高了离子液体对重金属离子的萃取性能,Co2+和Cd2+的萃取率分别由原来的2.06%和1.82%提高到96.37%和93.68%.不同螯合剂对离子液体萃取Co2+和Cd2+有一定的影响.离子液体碳链长度的增加有利于Co2+和Cd2+的萃取.与传统有机溶剂相似,离子液体萃取重金属离子过程中具有很强的pH摆动效应,当pH<2时,Co2+和Cd2+的萃取率几乎为0,而当pH>6时,Co2+和Cd2+的萃取率均大于90%.运用萃取过程中的pH摆动效应对Cd2+进行反萃取,实现了离子液体的回用.Extraction of CO^2＋ and Cd^2＋ into hydrophobic ionic liquids of [Bmim]PF6, [Hmim]PF6 and [Omim]PF6 is investigated for examining their removal from wastewater. The results indicate that the extraction rates of both Co^2＋ and Cd^2＋ are very low without chelator. However, the extraction rates are greatly enhanced from 2.06% to 96.37% for Co^2＋ and 1.82% to 93.68% for Cd^2＋ after the addition of chelator. The addition of different chelators also has a certain impact on the removal rates of heavy metal ions. The longer carbon bond the ionic liquids have, the better the extraction is. Similar to traditional solvent n-butanol, pH has a great impact on the removal rates of Co^2＋ and Cd^2＋. When pH〈2, the extraction rates of Co^2＋ and Cd^2＋ are close to zero. While for pH〉6, the extraction rates are above 90%. The pH swing effect is used to strip the heavy metal ions from ionic liquids, and the reuse of ionic liquids is realized.

关 键 词：离子液体 萃取 CO^2+ CD^2+ 废水 

分 类 号：TQ028.32[化学工程]