Scientists from the Sandia National Laboratories have discovered the mechanism to activate iron that is found in clay mineral structures. This activation can lead to an understanding of how to reactivate iron under an environment that does not have oxygen.
This discovery can help scientists to understand how contaminants like selenium, arsenic, and chromium can move through the environment and how they can enter waterways. These chemical principles can be used to create natural soil barriers that can remove the contaminants from water; this whole process can help improve our water filtration process.
According to the lead author of the research, Anastasia Ilgen, the main goal of geoscience is to recognize and understand how iron reacts; it is important for them to understand how contaminants move and transform in our environment.
The key constituent of the Earth's crust is iron, and it is also the fourth most common element. Minerals that contain iron make up a massive portion of our soil and sedimentary rocks. Chemical transformations and absorption on mineral surfaces that contains iron define the transport and fate of chemicals in our environment.
Adsorption is the attachment of contaminants onto mineral surfaces, and the chemical reactions on these minerals surfaces dictate how the chemicals move through our environment.
Ilgen also stated that iron in the soil could exist in two oxidation states: oxidized and reduced. This is crucial to the study because iron constantly circulates between these forms whenever there is a slight change in the condition of the soil.
She also said that clay minerals are very common in soils, and they usually contain iron in their structures. The surfaces of clay minerals are not reactive, and they only contain oxidized iron. Clay minerals absorb arsenic, but they do not transform it chemically. But these same surfaces become reactive as soon as a small amount of reduced iron is shown into the structure of the clay mineral.
Ilgen and her fellow researchers were able to discover the mechanism by which oxidized iron on clay mineral structures reacts under an environment without any oxygen and why amounts of reduced iron that can be traced are needed for the reactions to take place.
Being able to understand this mechanism can help explain the transport and fate of redox-sensitive contaminants and nutrients in the environment and why some of these nutrients and contaminants form even in the absence of oxygen.
Ilgen then said that her team would continue to research this topic, and they will explore the different conditions needed for iron to be reactive in sedimentary rocks and soil.
