Inhaltszusammenfassung

Arsenite was effectively immobilized by 2-line ferrihydrite at different pH values (4.0, 5.5 and 7.4) and adsorbent dosages (0.4, 1, and 2 g/L) in the absence of oxygen, showing an initial surface diffusion-controlled period (Stage I, <2 h) and a second mixed intra-particle and surface diffusion-controlled period (Stage II, >2 h). Dissolved δ56Fe increased during Stage I and decreased during Stage II, resulting from aging of ferrihydrite and equilibrium isotopic exchange, respectively. The fe...Arsenite was effectively immobilized by 2-line ferrihydrite at different pH values (4.0, 5.5 and 7.4) and adsorbent dosages (0.4, 1, and 2 g/L) in the absence of oxygen, showing an initial surface diffusion-controlled period (Stage I, <2 h) and a second mixed intra-particle and surface diffusion-controlled period (Stage II, >2 h). Dissolved δ56Fe increased during Stage I and decreased during Stage II, resulting from aging of ferrihydrite and equilibrium isotopic exchange, respectively. The ferrihydrite aging was hampered by both high As concentrations and high pH values close to the pHzpc, due to inhibition of mineral dissolution as a prerequisite for mineral transformation. During Stage I, As was adsorbed by both bidentate binuclear corner-sharing (2C) and monodentate mononuclear corner-sharing complexes (1V), while 2C dominated during Stage II. At stage I, As stability was mainly controlled by As-complexation, by both mineral transformation and As complexation at stage II. It is suggested that adsorbed-As stability can be optimized by regulating As complexation and mineral phases, which are of great significance for remediation of As-contaminated groundwater.» weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
3.42 - Geologie und Paläontologie

DDC Sachgruppe:
Geowissenschaften