离子液体萃取电镀废水中铅的研究

Study on Extraction of Lead in Electroplating Wastewater with Ionic Liquid

制备了三种不同阳离子侧链长度的离子液体[C_nMIM]PF_6(其中n=4、6、8),以它们为萃取剂,以双硫腙为螯合剂,构建了离子液体[C_nMIM]PF_6-双硫腙萃取体系。研究了该萃取体系对含铅废水中Pb^(2+)的萃取性能。研究发现,阳离子侧链增加有利于提高Pb^(2+)的萃取效果。另外,考察了萃取时间、萃取温度、pH值、含铅废水与离子液体的体积比对Pb^(2+)萃取率的影响。结果表明:[C_8MIM]PF_6-双硫腙萃取体系对含铅废水中Pb^(2+)的萃取率可达93.5%,并且Pb^(2+)萃取率受pH值影响很大。

Three kinds of acid polymeric ionic liquid [CnMIM]PF6 （n=4,6,8） were prepared. Ionic liquid [-CnMIM]PF6-dithizone extraction system was built with [CnMIM]PF6 as extractant and dithizone as chelating agent. The extraction performance of Pb^2＋ in lead-containing wastewater with this extraction system was studied. The research found that the increase of cationic carbon chain was helpful to improve the extraction efficiency of Pb^2＋. Furthermore, the influences of extraction time, extraction temperature, pH value, the volume ratio of ionic liquid [C8MIM]PF6 and water phase on the extraction rate of Pb^2＋ were investigated. Results showed that the extraction rate of Pb^2＋ in lead-containing wastewater could reach 93. 5% with this extraction system, and the extraction rate of Pb^2＋ was greatly affected by pH value.