饱和多孔介质中胶体沉淀释放过程的数值模拟

地下环境中可移动的胶体能够促进强烈吸附的污染物质的运移,而胶体自身在运移过程中也会伴随发生沉淀、释放。根据高岭石胶体的土柱出流实验,对不同离子强度条件下胶体在饱和多孔介质中的沉淀和释放行为进行分析,并采用不同模型对其过程进行数值模拟。结果表明,离子强度是影响胶体沉淀和释放过程的重要因素,随着离子强度的增加,胶体的出流峰值逐渐降低,即胶体在多孔介质中的沉淀量逐渐增大,且沉淀速率系数Kd与离子强度成正相关;模型拟合的释放系数与NaCl浓度显著相关,Grolimund模型可以很好地模拟胶体的沉淀过程(R20.95),但不能准确地模拟释放过程;而胶体运移方程耦合溶质运移方程能够模拟不同离子强度影响下胶体的释放过程(R20.9)。

Colloid Deposition and Release in Saturated Porous Media: Experiments and Simulations

Colloid transport has been shown to facilitate the transport of the contaminants in the subsurface and this process is affected by the attachment/detachment of the colloid. Two models were used in this study to simulate the colloid attachment/ detachment behavior, putting focus on colloid transport under different ionic strengths. To represent the colloid attachment/ detachment process, the kaolinite suspensions with different NaCl concentrations were applied to soil columns and then deionized water was use...