Abstract: Citric acid is an important organic acid and one of the largest amounts of fermentation products in the world. In the paper，it is comprehensively synopsized for the principles，advantages and disadvantages about the liquid-liquid extraction and liquid membrane extraction. The current development of two systems and problems need to be solved now are discussed in detail. They have little pollution，high extraction efficiency and low cost，but they are all easy to emulsify due to emulsifiers，proteins，polysaccharides contained in fermentation broth，meanwhile liquid membrane extraction method is complicated. Based on these shortages，ionic liquid applied to the citric acid extraction system is proposed. And the idea ensures the extraction keep its advantages，but also overcome its emulsification，while ion liquid can be recycled，which will increase its energy-efficiency，and reduce the cost of separation.

Key words: citric acid, extraction method, separation, extraction

摘要： 柠檬酸是世界上产量最大发酵产品之一，是一种重要的有机酸。本文较全面地总结了近年来液-液萃取法和液膜萃取法分离纯化柠檬酸的原理和优缺点，详细讨论了这两种体系的发展现状况以及亟待解决的问题，这两种方法均具有污染小、萃取率高、成本低等优点，但是由于发酵液中含有蛋白质、多糖等乳化剂，使得这两种均有易乳化的缺点，并且液膜萃取法操作复杂。基于这两种方法的不足之处，提出了将离子液体运用到柠檬酸的萃取体系中，具有很大的发展空间，既保证了萃取法本身的优势，又克服了易乳化的缺点，同时离子液体可以循环使用，能源效率高，分离成本低。

关键词: 柠檬酸, 萃取法, 分离, 提取