2024/11/25 by Xu Zhang, David J. Wilson, Maartje Hamers +4 · 1 voice
Chemistry · Engineering · Environmental Science · #Chemical Synthesis and Characterization #Extraction and Separation Processes #Radioactive element chemistry and processing
paper · pdf · doi:10.1021/acsearthspacechem.4c00205
openalex publication_date 2024/11/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/19
High Resolution Image Download MS PowerPoint Slide Chemical weathering processes play a key role in regulating the global climate over geological time scales. Lithium (Li) isotope compositions have proven to be a robust proxy for tracing weathering processes that produce secondary minerals, such as clays and oxides, with a focus often placed on Li adsorption to, or incorporation into, clay minerals. In addition, the interaction between Li and Fe-oxides has long been assumed and discussed based on field observations, but experimental constraints on this process are lacking. Here, we investigated the geochemical behavior of Li during its sorption onto individual Fe-oxides, including goethite, hematite, wüstite, and magnetite. With a point of zero charge at ∼7.7, poorly crystallized goethite nanoparticles take up ∼20% of dissolved Li over a pH range from ∼4 to ∼10, rising to ∼90% at pH ∼12. In contrast, the sorption of dissolved Li is insignificant for well-crystallized Fe-oxides (hematite, wüstite, magnetite, and goethite). This Li uptake by poorly crystallized goethite is likely attributed to dissolution and reprecipitation reactions at poorly crystalline goethite surfaces. The goethite particles preferentially take up light 6 Li isotopes, resulting in an isotope fractionation of Δ 7 Li oxide-fluid ∼ −16.7 to −20.1‰. Overall, our study provides valuable data to better understand the processes occurring in highly weathered soil and sediment profiles that are rich in Fe-oxides, such as laterites. This research also emphasizes the significance of chemistry at mineral surfaces during mineral–water interactions and illuminates the mechanisms of large-scale Li extraction for future applications.