Kinetics of Cation and Oxyanion Adsorption and Desorption on Ferrihydrite: Roles of Ferrihydrite Binding Sites and a Unified Model

• DOI: 10.1021/acs.est.7b03249
• Publication Date: 2017-08-10T13:09:36Z
• Authors: Lei Tian; Zhenqing Shi; Yang Lu; Alice C. Dohnalkova; Zhang Lin; Zhi Dang
• Keywords: Ferrihydrite; Oxyanion

Quantitative understanding the kinetics of toxic ion reactions with various heterogeneous ferrihydrite binding sites is crucial for accurately predicting dynamic behavior contaminants in environment. In this study, As(V), Cr(VI), Cu(II), and Pb(II) adsorption desorption on was studied using a stirred-flow method, which showed that metal adsorption/desorption highly dependent reaction conditions varied significantly among four metals. High resolution scanning transmission electron microscopy coupled energy-dispersive X-ray spectroscopy all metals were distributed within aggregates homogeneously after reactions. Based equilibrium model CD-MUSIC, we developed novel unified applicable both cation oxyanion ferrihydrite, able to account heterogeneity sites, different properties cations oxyanions, variations solution chemistry. The described kinetic results well. We quantitatively elucidated how formation surface complexes controlled at time scales. Our study provided modeling method ferrihydrite.