Our current understanding of Earth's core formation is limited by the fact that this profound event is far removed from us physically and temporally. The composition of the iron metal in the core was a result of the conditions of its formation, which has important implications for our planet's geochemical evolution and physical history. We present experimental and theoretical evidence for the effect of pressure on iron isotopic composition, which we found to vary according to the alloy tested (FeO, FeH(x), or Fe3C versus pure Fe). These results suggest that hydrogen or carbon is not the major light-element component in the core. The pressure dependence of iron isotopic composition provides an independent constraint on Earth's core composition.
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http://dx.doi.org/10.1126/science.aad9945 | DOI Listing |
Environ Sci Technol
January 2025
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China.
Cadmium (Cd) isotopes have recently emerged as novel tracers of Cd sources and geochemical processes. Widespread clay minerals play a key role in Cd migration due to their strong adsorption capacity, but the mechanism of Cd isotope fractionation during adsorption onto clay minerals is poorly understood. Here, we experimentally investigated the adsorption mechanisms of Cd on montmorillonite (2:1) and kaolinite (1:1) by using extended X-ray absorption fine structure (EXAFS) spectroscopy.
View Article and Find Full Text PDFSci Rep
January 2025
Northwest Oilfield Company, SINOPEC, Ürümqi, 830011, China.
Deep oil reservoirs are becoming increasingly significant fields of hydrocarbon exploration in recent decades. Hydrothermal fluid flow is deemed as a potentially crucial factor affecting the occurrence of deep oil reservoirs, such as enhancing porosity/permeability of reservoirs, accelerating oil generation and thermal cracking, and modifying organic properties of crude oils. Understanding the interplay between hydrothermal fluids and crude oils would provide useful constraints for reconstructing hydrocarbon accumulation processes and predicting the distribution patterns of crude oils.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, PR China; Key Laboratory of Optic-Electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China. Electronic address:
Background: The excessive application of enrofloxacin (ENR) results in residues contaminating both food and the environment. Consequently, developing robust analytical methods for the selective detection of ENR is crucial. The photoelectrochemical (PEC) sensor has emerged as a highly sensitive analytical technique that has seen rapid development in recent years.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, 0179, Tbilisi, Georgia. Electronic address:
Background: Isotopologues resulting from the labelling of molecules with deuterium have attracted interest due to the isotope effect observed in chemistry and biosciences. Isotope effect may also play out in noncovalent interactions and mechanisms leading to intermolecular recognition. In chromatography, differences in retention time between isotopologues, as well as between isotopomers have been observed resulting in two different elution sequences (isotope effects): the normal isotope effect when heavier isotopologues retain longer than lighter analogues, and the inverse isotope effect featuring the opposite elution order.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany; Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany. Electronic address:
Ecological impacts of tire wear particles (TWPs) on microbial communities and biogeochemical cycles in freshwater remain largely unknown. Here, we conducted a microcosm experiment to investigate interactions between the overlying water and sediment without and with TWPs addition in a rural vs. urban lake system.
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