Adsorption and Desorption Behaviors of Sr on Montmorillonite: A Triple Sr Isotope Perspective

Hou Chun Liu, Jia You Hsieh, Yen Hong Chen, Chen Feng You, Wei Teh Jiang, Hsin Yi Wen

研究成果: Article同行評審

2 引文 斯高帕斯(Scopus)

摘要

Montmorillonite is a widespread mineral, which affects the migration of Sr in the critical zone. Hydrochemical factors influencing Sr adsorption have been evaluated in the literature through laboratory batch experiments. Since those experiments were conducted using high-concentration and high-purity standard solutions, the influences of chemical matrices or element relative concentrations in water remain unclear. Here, we reassessed the adsorption and desorption behaviors of Sr on montmorillonite using natural waters with various chemical matrices and ionic strengths. Triple Sr isotopes (87Sr/86Sr and δ88/86Sr) were used to trace the exchange processes between the minerals and the waters. Adsorption and desorption occurred in all processed samples, but to varying degrees. These phenomena (especially desorption) were principally controlled by the ionic competition of divalent ions (i.e., Ca and Mg), rather than by ionic strength. Sr isotope fractionation occurred during adsorption. Isotopically lighter Sr was preferentially adsorbed: the mean Δ88/86Srmineral-water (a value independent from the clay type) was -0.17‰. Consequently, water δ88/86Sr depended on both the mixing of mineral-bound and initial water Sr and on the degree of Sr adsorption; moreover, the exchange process was a reversible reaction and reached its chemical and isotopic equilibrium within a short time.

原文English
頁(從 - 到)2250-2260
頁數11
期刊ACS Earth and Space Chemistry
6
發行號9
DOIs
出版狀態Published - 2022 9月 15

All Science Journal Classification (ASJC) codes

  • 地球化學與岩石學
  • 大氣科學
  • 空間與行星科學

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