Kabbadj S, Rongy L, De Wit A
Nonlinear Physical Chemistry Unit, Université libre de Bruxelles, CP231, Boulevard du Triomphe, 1050 Bruxelles, Belgium.
Phys Rev E. 2023 Jun;107(6-2):065109. doi: 10.1103/PhysRevE.107.065109.
When two partially miscible systems are put in contact, one phase, A, can dissolve into the other one with a given solubility. Chemical reactions in the host phase can impact this dissolution by consuming A and by generating products that impact the solubility of A. Here, we study theoretically the optimal conditions for transfer of a reactant A in a host phase containing a species B when a bimolecular A + B → C reaction generates a product C that linearly decreases the solubility of A. We have quantified numerically the influence of this variable solubility on the reaction-diffusion (RD) concentration profiles of all species in the host phase, on the temporal evolution of the position of the reaction front, and on the flux of A through the interface. We have also computed the analytical asymptotic concentration profiles, solutions at long times of the RD governing equations. For a fixed negative effect of C on the solubility of A, an increase in the initial concentration of reactant B or an increase in the diffusion rate of species B and C results in a larger flux of A and hence a larger amount of A dissolved in the host solution at a given time. However, when the influence of C on the solubility increases, the mass transfer decreases. Our results help understand to what extent a chemical reaction can optimize the reactive transfer of a solute to a host phase with application to, among other things, the geological sequestration of carbon dioxide in an aquifer.
当两个部分互溶的体系接触时，一相（A）能以给定的溶解度溶解到另一相中。主相中的化学反应可通过消耗A以及生成影响A溶解度的产物来影响这种溶解过程。在此，我们从理论上研究了在含有物种B的主相中反应物A转移的最佳条件，此时双分子反应A + B → C生成产物C，该产物会使A的溶解度线性降低。我们已通过数值方法量化了这种可变溶解度对主相中所有物种的反应扩散（RD）浓度分布、反应前沿位置的时间演化以及A通过界面的通量的影响。我们还计算了分析渐近浓度分布，即RD控制方程在长时间下的解。对于C对A溶解度的固定负效应，反应物B初始浓度的增加或物种B和C扩散速率的增加会导致A的通量更大，从而在给定时间内有更多的A溶解在主溶液中。然而，当C的影响增加时，传质会减少。我们的结果有助于理解化学反应在何种程度上可以优化溶质向主相的反应性转移，这在诸如含水层中二氧化碳的地质封存等方面有应用。
