Elucidating the binding configuration of uranium at the biotite-water interface.

Understanding the binding configuration of uranium on biotite is crucial for elucidating the environmental behavior of U(VI) and addressing emergency scenarios in disposal repositories. This investigation demonstrated that U(VI) adsorption on biotite was significantly affected by pH, while a lesser impact from ionic strength. Moreover, the presence of phosphate and humic acid (HA) exerted a substantial enhancing influence on U(VI) adsorption (adsorption rate increased by over 20%). X-ray photoelectron spectroscopy (XPS) analysis revealed that elevated Fe(II) contents within biotite structures facilitated the reduction of partial U(VI) to form U(V/IV)/U(IV), i.e., mineralization products, under both aerobic and anaerobic conditions. [ABSTRACT FROM AUTHOR]