离子液体对有机染料的萃取行为

Extraction behavior of dyes with hydrophobic ionic liquid

以疏水性离子液体1-甲基-3-丁基咪唑六氟磷酸盐([bmim]PF6)为萃取剂,液-液体系中对6种常见有机染料结晶紫、孔雀绿、罗丹明B、亚甲基蓝、铬天青S以及偶氮氯膦Ⅲ的萃取行为进行了研究,考察了溶液pH、萃取时间、离子液体浓度以及盐的含量对萃取率的影响.结果表明,离子液体对水中不同结构染料的萃取能力有很大差异:在pH 3—9的条件下,离子液体对结晶紫和亚甲基蓝的萃取能力很强,萃取率均在90%以上;在pH值3—5的条件下,对孔雀绿的萃取率在86%以上;在pH值为3的条件下,对罗丹明B的萃取率为94%,且酸度减小时萃取率下降;在pH 7—11时对铬天青S和偶氮氯膦Ⅲ的萃取率分别小于36%和29%,且酸度增大时萃取率下降.对各种染料均可在5—10 min内完成萃取,萃取后分相迅速,相界面清晰,无浑浊或第三相形成,有着传统有机溶剂无法比拟的优点.本研究对采用离子液体萃取净化染料废水和回收废弃燃料具有一定的参考价值.

Using a hydrophobic ionic liquid, 1-methyl-3-butyl imidazole six hexailuomphosphoric acid （[ bmim]PF6）, as an extractant, the extraction performance of six common organic dyes such as crystal violet, malachite green, rhodamine B, methylene blue, chrome azurol S, and chlorophosphonazo HI in the liquid-liquid extraction system were studied. The effect of the pH value of solution, extraction time, concentration of [ bmim ] PF6, and salt content on the extraction rates of dyes were examined. It is shown that the extraction potential of different dyes by [ bmim ] PF6 was different. The extraction potential of crystal violet and methylene blue in the condition of pH 3 9 were very high and the rates above 90%. The extraction rate of malachite green in pH 3--5 was above 86%. The rate of rhodamine B in pH 3 was 94% and decreased with decreasing acidity. The rates of chrome azurol S and chlorophosphonazo ]II in pH 7-11 were below than 36% and 29%, respectively and decreased with increasing acidity. Furthermore, the extraction of various dyes was completed in 5-10 min and the phase splitting was rapid and clear after the extraction. No muddy phase or formation of the third phase occured, which is superior to for the traditional organic solvents. The obtained results have reference values for the purification of dye wastewaters and reuse of scrap dyes using the ionic liquids.