Meza Isabel, Jemison Noah, Gonzalez-Estrella Jorge, Burns Peter C, Rodriguez Virginia, Sigmon Ginger E, Szymanowski Jennifer E S, Ali Abdul-Mehdi S, Gagnon Kaelin, Cerrato José M, Lichtner Peter
Department of Civil, Construction & Environmental Engineering, MSC01 1070, University of New Mexico, Albuquerque, New Mexico 87131, USA.
Center for Water and the Environment, UNM, Albuquerque, NM, USA.
Chem Geol. 2023 Oct 5;636. doi: 10.1016/j.chemgeo.2023.121642. Epub 2023 Jul 26.
We integrated aqueous chemistry analyses with geochemical modeling to determine the kinetics of the dissolution of Na and K uranyl arsenate solids (UAs) at acidic pH. Improving our understanding of how UAs dissolve is essential to predict transport of U and As, such as in acid mine drainage. At pH 2, NaH(UO)(AsO)(HO) (NaUAs) and KH(UO)(AsO)(HO) (KUAs) both dissolve with a rate constant of 3.2 × 10 mol m s, which is faster than analogous uranyl phosphate solids. At pH 3, NaUAs (6.3 × 10 mol m s) and KUAs (2.0 × 10 mol m s) have smaller rate constants. Steady-state aqueous concentrations of U and As are similarly reached within the first several hours of reaction progress. This study provides dissolution rate constants for UAs, which may be integrated into reactive transport models for risk assessment and remediation of U and As contaminated waters.
我们将水相化学分析与地球化学建模相结合，以确定酸性pH条件下钠和钾的铀酰砷酸盐固体（UAs）的溶解动力学。加深我们对UAs如何溶解的理解对于预测铀和砷的迁移至关重要，例如在酸性矿山排水中。在pH值为2时，NaH(UO)(AsO)(HO)（NaUAs）和KH(UO)(AsO)(HO)（KUAs）的溶解速率常数均为3.2×10 mol m s，这比类似的铀酰磷酸盐固体更快。在pH值为3时，NaUAs（6.3×10 mol m s）和KUAs（2.0×10 mol m s）的速率常数较小。在反应进行的最初几个小时内，铀和砷的稳态水相浓度也会以类似的方式达到。这项研究提供了UAs的溶解速率常数，可将其纳入反应性传输模型中，用于对受铀和砷污染水体的风险评估和修复。
