Characterization of an Improved Extraction Chromatographic Material for the Separation and Preconcentration of Strontium from Acidic Media

Abstract

The determination of radiostrontium in biological and environmental samples generally requires its preliminary separation and preconcentration, both to remove radionuclides that may interfere with subsequent b-counting and to free it from the large quantities of inactive substances present (e.g., calcium). Extraction chromatography employing an inert support impregnated with a solution of a crown ether in an oxygenated, aliphatic solvent (e.g., 1-octanol) has previously been demonstrated to provide a simple and effective method for the isolation of strontium from a variety of samples for subsequent determination. In this work, it is shown that a chromatographic resin capable of retaining strontium efficiently and selectively from acidic media can be prepared simply by dispersing a crown ether alone on an appropriate support. This "solventless" resin is demonstrated to offer several advantages over its conventional analog, in particular, good physical stability, higher capacity, and improved metal ion retention. In addition, extended X-ray absorption fine structure measurements are shown to provide insight into the coordination environment of metal ions sorbed by the resin.This article is not subject to U.S. copyright law.

Evaluation of solid-supported room-temperature ionic liquids containing crown ethers as media for metal ion separation and preconcentration

“…As shown, in contrast to the results obtained by Makote (34) for DCH18C6, the sorbent incorporating only DtBuCH18C6 displays significant retention of radiostrontium, yielding a D w of nearly 80 at the highest acidities examined. Similar strontium ion retention behavior is seen for the sorbent incorporating a solution of DtBuCH18C6 in 1octanol, although a decline in the acid dependency is seen at sufficiently high aqueous acidities.This observation is consistent with previous results for polymer-based EXC resins, for which little effect on strontium ion retention by a crown ether-loaded support was noted upon introduction of 1-octanol(4). Again in contrast to the results of Makote(34), however, much the same strontium ion uptake is observed for the sorbent incorporating a solution of the crown ether in the ionic liquid.…”

“…Extraction chromatography, a type of liquid chromatography in which the stationary phase comprises a metal ion extractant or a solution of the extractant in an appropriate diluent sorbed on an inert (often, polymeric) support, has proven to be of extraordinary utility in the development of methodology for the determination of a variety of radionuclides in environmental (e.g., soil) and biological (e.g., bioassay) samples (1)(2)(3). Despite its many advantages, however, extraction chromatography suffers from several significant limitations (2)(3)(4). First, because the extractant is sorbed rather than covalently bonded to the support, the physical stability of extraction chromatographic (EXC) resins can be inadequate for many applications.…”

Efficiency of combining limestone, sawdust and microorganisms to treat Zinc and Manganese in AMD in Mao Khe, Quang Ninh

“…Using ionic exchange method to separate heavy metal ions from solution, simultaneously, an equivalent amount of other ions in solution. Ionic exchange method is used primarily in the treatment of hardness and salt removal in waste water and they can also be used for the removal and recovery of heavy metals in wastewater (Acheampong et al, 2010;Bahlo & Wach, 1992;Blume, 2001; Dietz et al, 2005). Although the use of ionexchange method is simple, but the material need to be frequently treated and recycled or storage of waste, so it can be an additional cost.…”