氧化石墨烯驱动下渗透土层中重金属污染物的沉积-释放过程及净化机制

构建一个考虑沉积历史以及温度效应影响的非线性的悬浮物质静态吸附-解吸模型，进而建立渗透水流作用下能反映悬浮物质与多孔介质固体基质之间“吸附滞后”效应的沉积动力学模型。其中，引入“反应速率常数”的概念来体现多孔介质中悬浮物质沉积、释放和迁移的非平衡态水动力学过程，揭示悬浮物质浓度和渗透速度随时间变化情况下悬浮物质迁移过程的物理本质。利用土柱渗透迁移试验，研究氧化石墨烯驱动下已沉积重金属离子的释放过程（物理过程和化学过程），特别关注氧化石墨烯对重金属离子的吸附作用和络合作用。此外，还研究氧化石墨烯注入浓度和渗透速度的影响，分析氧化石墨烯与重金属离子相互作用过程的内在机制及其温度效应。理论上，建立氧化石墨烯与重金属离子耦合迁移过程的控制方程和求解方法以及全新的迁移参数试验标定方法。最终，发展一个利用氧化石墨烯来净化土层中已沉积重金属污染物的实用技术。

A nonlinear attachment-detachment model with adsorption hysteresis for the transport of suspension-colloidal particles in porous media is constructed by laboratory tests, which considers the influences of deposition history and temperature effect. This model can reflect the hysteretic effects between suspended particles and solid matrix in seepage water. Among these, a physical parameter of reaction rate constant is introduced to indicate the non-equilibrium hydrodynamic process of deposition, release and transport, which reveals the physical essence of transport process under the changes of contaminant concentration and seepage velocity with time. The release process (physical and chemical process) of heavy metal contaminants deposited in the solid matrix of porous media driven by graphene oxide is studied by means of soil column penetration test. Especially, the adsorption and complexation effects of heavy metal ions by graphene oxide, as well as the influence of injection concentration and water velocity, are studied systematically, which can reflect the internal mechanism of the coupling process. In theory, the governing equations and solution methods for the coupled transport of graphene oxide and heavy metal ions are established, and the new experimental calibration methods of transport parameters in the coupled transport process are also proposed. Finally, a practical technology using graphene oxide to purify heavy metal ions in contaminated soils will be developed, which provides a new way for the soil remediation after heavy metal pollution.