Chlorinated solvents such as trichloroethylene (TCE) are worldwide contaminants in soils and waters. They represent very troublesome pollutants due to their high density, mobility, volatility, toxicity, and persistence. Despite intensive research over the past several decades, major challenges to clean soils and water contaminated with these pollutants remain.
One of the clean-up approaches for remediation of contaminated groundwater is chemical reduction. Green rust (GR), layered iron(II)-iron(III) hydroxide, is one of the promising reductant materials because of high reducing reactivity and easy to manufacture. The reducing capacity of GR has shown for both inorganic and organic contaminants, e.g., nitrate, chromate, carbon tetrachloride and nitroaromatics. However, fast reduction of chlorinated ethylenes has not been seen with GR, which has significantly hindered its potential for broader application in pollutant degradation.
We have recently found that biochar is capable of catalyzing the reduction of chlorinated ethylenes by GR, resulting in an extremely fast reduction rate. The new finding of the surprising reactivity of the iron-biochar composite no doubt opens a new perspective of remediation of contaminated groundwater. However, it is not clear whether the groundwater solutes have negative impacts on the reactivity and how they influence the composite over time in a long term in terms of structure and reactivity. Figuring out these questions would be very useful to assess the longevity of the iron-biochar composite during subsurface remediation.
The main objective of this project is to investigate the effects of groundwater solutes on the transformation and reactivity of the iron-biochar composite. For this, you may
Measure the rate of TCE reduction by the composite that has been aged under different solute solutions for different time scales to investigate how the reactivity change with time and how the reactivity varies with the different solute solution.
Characterize the above-aged composite by using multiple approaches to figure out how GR (and even the iron-biochar composite) transform over time under different solute solutions.
Try to explain the mechanism of how the groundwater solutes impact the reactivity of the composite based on the above observations.
The project will be connected with the Innovation Foundation project, so you also have some opportunities to coordinate with Danish companies. The work will be carried out in the Section for Environmental Chemistry and Physics, Department for Plant and Environmental Sciences, Faculty of Science at Copenhagen University, under the supervision of postdoc Jing Ai (firstname.lastname@example.org) and prof. Hans Chr. Bruun Hansen (email@example.com).