Reactive Transport¶
Reactive constituent transport in groundwater refers to the complex movement and transformation of dissolved substances as they migrate through the subsurface environment. This phenomenon is characterized by the interaction of these constituents with the surrounding geological materials and the potential for chemical reactions to occur, altering the composition of the groundwater. It plays a critical role in environmental processes, as it encompasses the transport of contaminants, nutrients, and other solutes, often involving reactions such as sorption, degradation, precipitation, and dissolution. Understanding reactive constituent transport is essential for managing and mitigating groundwater contamination, optimizing groundwater remediation strategies, and safeguarding the quality of groundwater resources.
Reactions¶
The figure below is a classification of different kinds of reactions (CITE source)
Some reaction “categories” important in groundwater include:
Adsorbtion - solute clings to surface due to various attractive forces - usually electrostatic.
Ion-Exchange - ions are attracted to mineral surfaces substitute themselves into the mineral structure. Zeolites are examples of natural ion-exchange materials.
Chemisorption - solute is incorporated into a sediment by chemical reaction.
Absorbtion - solute diffuses into solid matrix and clings to interior surfaces. (Notice the “b” replaces the “d” in adsorbtion)
All these reactions are controlled to a great extent by solution pH, EH, and salinity.