Geun-Sik Choi

Separation and Preconcentration of Strontium from Calcium in Aqueous Samples by Supported Liquid Membrane Containing Crown Ether

Supported liquid membrane containing crown ether (DC18C6) and dinonylnaphthalenesulfonic acid (DNNS) is proposed for separation and preconcentration of strontium in an aqueous environmental sample. The effects of carriers in membrane on permeability and selectivity of Sr2+ were characterized. Crown ether has a key role in the selective transport of strontium ion while DNNS facilitates the transport of both Sr2+ and Ca2+. A strontium ion can be selectively transported to an acidic strip solution against its concentration gradient across the membrane. This SLM can be used as an efficient method for separation and preconcentration of strontium in a neutral aqueous sample.

Application of a high-temperature tube furnace and liquid scintillation counter for radioactivity determination of 14C and 3H in solid waste samples

This study reports the method for measuring 3H and 14C in sludge samples from the National Physical Laboratory (NPL) proficiency program (Environmental Radioactivity Proficiency Test Exercise 2012). The samples were combusted by a high-temperature furnace and trapped beta-emitting nuclides, especially 3H and 14C, were measured by LSC. The validation of method was checked by using initial calibration verification (ICV) samples and laboratory control sample (LCS). The results were in agreement with assigned radioactivity concentration for 3H and 14C. Thus, reliable and accurate method for 3H and 14C was developed using high-temperature tube furnace and LSC.