【摘要】 以乙醇为改性剂,超临界CO2络合萃取乳酸钙中痕量重金属离子。考察了络合剂种类及用量、乙醇用量、温度、压力、萃取时间等对萃取效果的影响。结果表明,不同络合剂对不同金属离子的萃取效果有明显差异;乙醇用量对金属离子的萃取效果影响不明显;温度在50℃时,金属离子总萃取率可达80%以上;萃取时间比萃取压力的影响更为显著,表明络合反应控制着该过程。确定优化的萃取工艺条件如下:10 mL乙醇作改性剂、温度50℃、CO2流速13 L.h-1、压力20 MPa、萃取时间90 min、二乙基二硫代氨基甲酸钠与四丁基溴化铵复配物用量为样品质量的2%。更多还原

【Abstract】 This paper investigates the effects of chelating agent,modifier(ethanol) amount,temperature,pressure and extraction time on supercritical CO2 chelating-extraction of trace heavy metal ions from calcium lactate.The results indicate that different chelating agents give remarkable different efficiencies in extraction;Increasing the modifier amount in the supercritical CO2,the extraction efficiencies for Pb,As and Hg do not increase noticeably;The total removal rate is above 80% when the temperature is 50℃;And the extraction time has more obvious influence on the process than the pressure,so that the chelating reaction is a rate-control step.The optimum extraction conditions are as follows: 10 mL ethanol,temperature 50℃,flow rate of CO2 13 L·h-1,pressure 20 MPa,extraction time 90 min,the mass ratio of the mixture of tetrabutyl bromide and sodium diethyldithiocarbamate to sample is 2%.更多还原