90Sr在SuperLig®620固相萃取颗粒上的吸附性能研究

Adsorption of 90Sr on SuperLig®620 Solid Phase Extraction Beads

  • 摘要: 为了建立SuperLig®620分离水中90Sr的方法,研究了接触时间、硝酸酸度、柠檬酸铵浓度、干扰核素等对90Sr在SuperLig®620固相萃取颗粒上分配系数Kd的影响。在0.1 mol/L HNO3介质中,接触时间大于30 min时,Kd大于1 000 mL/g。在c(H+)>1 mmol/L时,SuperLig®620不吸附137Cs、239Pu、90Y,但可吸附133Ba。通过调节解吸时柠檬酸铵的浓度,可排除133Ba对90Sr分离的干扰。研究了SuperLig®620色层柱分离水中90Sr的方法,将样品调节至0.1 mol/L HNO3上柱,首先用10Vc(柱体积Vc=0.1 mL)0.1 mol/L HNO3洗涤杂质,然后依次用9Vc 0.1 mol/L柠檬酸铵、13Vc 1.8 mol/L柠檬酸铵解吸90Sr、133Ba。该流程对90Sr的回收率大于99%,对主要干扰核素的去污因子大于3×103,适用于环境水中90Sr的分析。

     

    Abstract: For setting a procedure of separating 90Sr in aqueous using SuperLig®620, the performance of SuperLig®620 solid phase extraction beads for the adsorption of strontium in aqueous solution was studied. The influences of contact time, nitric acid concentration, strontium carrier and ammonium citrate concentration on distribution coefficient Kd were studied. The Kd is more than 1 000 mL/g when contact time is longer than 30 min in 0.1 mol/L HNO3. The resin can not adsorb any other radionuclides except 133Ba when c(H+)>1 mmol/L. 90Sr and 133Ba can be eluted respectively using different concentrations of ammonium citrate. Based on the results, a separation procedure of 90Sr in environmental water samples using SuperLig®620 solid phase extraction beads was presented. The optimal separation was found using a 0.1 mol/L HNO3 load solution with a 10Vc 0.1 mol/L HNO3 to wash potential interferences. Then 90Sr was eluted using 9Vc 0.1 mol/L ammonium citrate. The yield of strontium is more than 99%, and the decontamination factor is more than 3×103.

     

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