含金属离子赖氨酸水溶液的萃取分离

采用二(2-乙基己基)磷酸(P204)作萃取剂,航空煤油作稀释剂,对含有钙、镁、钠、钾等金属离子的赖氨酸水溶液进行萃取,以蒸馏水作为反萃取剂对有机相进行反萃取分离实验.结果表明,原料液初始pH值在4～5、P204与煤油体积比为3:2、有机相与水相比为2:1、反应萃取时间大于30min、搅拌转速约200rpm时,能够取得较好的萃取效果.以初始pH值≥3.5的蒸馏水为反萃取剂,蒸馏水与有机相体积比4:1,在150rpm的转速下搅拌20min能够较为完全地分离出赖氨酸,然后在其它条件相同的情况下,用初始pH＜1的蒸馏水对有机相再次反萃取可分离出金属离子,从而实现萃取剂的重复利用.

Separation of metal ions with amino acids in aqueous solution

In this work,lysine aqueous solution containing metal ions,such as calcium,magnesium,sodium and potassium,was extracted by using of P204 as extractant.Then,the extracted phase with lysine and metal ions can be counter-extracted by using of distilled water as the stripping agent.Experimental results show that when the pH of aqueous solution is 4 to 5,the volume ratio of P204 and kerosene is 3:2,the volume ratio of organic phase and aqueous phase is 2:1,extraction time is longer than 30 minutes and stirring speed about 200 rpm,a good extraction efficiency can be achieved.The separation of lysine from metal ions in the extracted phase can be obtained under following conditions: the pH >3.5,phase ratio of distilled water and organic phase is 4:1,mixing time is longer than 20 minutes at 150 rpm.At last,the metal ions were separated from the extracted phase under almost same experimental conditions only by changing the pH value to less than 1.At the same time,the extractant can be recovered and reused.