The University of Texas at Austin, Department of Geological Sciences, 2305 Speedway Stop C1160, Austin, TX 78712-1692, United States of America.
Karlsruher Institut für Technologie, Institut für Nukleare Entsorgung, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen 76344, Germany.
J Contam Hydrol. 2018 Sep;216:27-37. doi: 10.1016/j.jconhyd.2018.08.001. Epub 2018 Aug 14.
The effects of acidity and salinity on solute transport in porous media are important to a diverse range of fields from seawater intrusion to nuclear waste storage. Recent transport experiments in quartz sand show the difficulty in capturing the coupling of acidity and salinity under acidic conditions for this system. Here we study the ability of different surface complexation models to capture this coupling, through an analysis of the reactive transport equations in the limit of no diffusion. This chromatographic analysis leads to a graphical representation of the full set of solutions in the phase plane, thus allowing a comprehensive comparison of the transport behavior arising from different SCMs. The analysis shows that the predicted coupling is improved by including amphoteric behavior of the quartz surface. The inclusion of a secondary proton sorption reaction increases the magnitude of surface charge under acidic conditions strengthening the acidity-salinity coupling. This suggests that even though the overall surface is negative above the point of zero charge, positively charged sites play an important role in the reactive transport of acidity and salinity.
酸度和盐度对多孔介质中溶质运移的影响对于从海水入侵到核废料储存等各种领域都很重要。最近在石英砂中的输运实验表明，在该体系的酸性条件下，很难捕捉到酸度和盐度的耦合。在这里，我们通过分析无扩散条件下的反应输运方程，研究了不同表面络合模型捕捉这种耦合的能力。这种色谱分析导致在相平面上对整个解的集合进行图形表示，从而可以对不同 SCM 产生的输运行为进行全面比较。分析表明，通过包含石英表面的两性行为，可以改善预测的耦合。包含二次质子吸附反应增加了酸性条件下表面电荷的大小，从而增强了酸度-盐度的耦合。这表明，即使在零电荷点以上整个表面带负电，带正电荷的位点在酸度和盐度的反应输运中也起着重要作用。
