Sequential ultrasonic leaching of strontium from sediments

Abstract

The effects of ultrasonic excitation on the sequential leaching of Sr from sediments have been investigated. The sequential leaching scheme of Tessier partitions metals in sediments into exchangeable, carbonate bound, oxide bound, organic bound, and residual binding fractions. The Sr in the leachates was determined by flame atomic absorption spectrometry. Leaching rate experiments using conventional and ultrasonic leaching showed that the ultrasonic leaching method (ULM) produces comparable results to the conventional procedure. In addition, this method reduces the time required for Tessier fractionation from 21 h to 1.7 h. Sequential ultrasonic leaching procedures were established as a result of the extraction rate experiments. The precision obtained from 21 replicate ULM yielded an average relative standard deviation % of 9.2, 10.3, 11.7, 8.6, and 12.8 for exchangeable, carbonate, oxide, organic, and residual fractions, respectively. The precision variance between the means of the two leaching methods was not significant at 0.05 probability for Sr. The recoveries of total Sr using NIES CRM-2 ranged from 75 % to 101 % for the conventional procedure and 84 % to 109 % for the ULM.