Abstract
In this study, natural illite is introduced to support nanoscale zero valent iron (NZVI). The chemical composition and the physical properties of illite supported nanoscale zero valent iron (I-NZVI) are systematically investigated, and I-NZVI is found to significantly reduce the agglomeration of the NZVI particles. A comparison of the U removal capacity between I-NZVI and NZVI over various reaction times is then conducted. With an initial concentration of U at 200 μg/L, the I-NZVI removal capacity of U is as high as 3.41 mg U/g Fe, in contrast to 2.01 mg U/g Fe by NZVI at a dosage of 0.1 g/L. The initial pH of the reaction system determines the U removal capacity of I-NZVI, since it controls the speciation of U and the electron transfer processes during the reaction. Overall, based on the comprehensive understandings of the morphological change, variations in the crystalline structure, and the valence states of U and Fe, the removal mechanisms of U by I-NZVI can be concluded as the following processes: (1) the adsorption and incorporation of U(VI) onto the surface of I-NZVI, (2) the incorporation and reduction of U(V) into Fe(II), and (3) the reduction and precipitation of U(IV) with iron.
Published Version
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