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Title: Phosphate and phytate adsorption and precipitation on ferrihydrite surfaces

Phosphorous (P) sorption on mineral surfaces largely controls P mobility and bioavailability, hence its pollution potential, but the sorption speciation and mechanism remain poorly understood. In this study, we have identified and quantified the speciation of both phosphate and phytate sorbed on ferrihydrite with various P loadings at pH 3–8 using differential atomic pair distribution function (d-PDF) analysis, synchrotron-based X-ray diffraction (XRD), and P and Fe K-edge X-ray absorption near edge structure (XANES) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. With increasing P sorption loading for both phosphate and phytate, the sorption mechanism transits from bidentate-binuclear surface complexation to unidentified ternary complexation and to precipitation of amorphous FePO 4 and amorphous Fe-phytate. At a given P sorption loading, phosphate precipitates more readily than phytate. Both phosphate and phytate promote ferrihydrite dissolution with phytate more intensively, but the dissolved FeIII concentration in the bulk solution is low because the majority of the released Fe III precipitate with the anions. Results also show that amorphous FePO 4 and amorphous Fe-phytate have similar PO 4 local coordination environment. In conclusion, these new insights into the P surface complexation and precipitation, and the ligand-promoted dissolution behavior improve our understanding of P fate inmore » soils, aquatic environment and water treatment systems as mediated by mineral-water interfacial reactions.« less
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ;  [1] ; ORCiD logo [3] ; ORCiD logo [4] ; ORCiD logo [1]
  1. Univ. of Wyoming, Laramie, WY (United States). Department of Ecosystem Science and Management
  2. University of Saskatchewan, Saskatoon (Canada). Canadian Light Source
  3. Huazhong Agricultural University, Wuhan (China). Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment
  4. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division, Advanced Photon Source
Publication Date:
Grant/Contract Number:
AC02-06CH11357; AC02-76SF00515
Accepted Manuscript
Journal Name:
Environmental Science: Nano
Additional Journal Information:
Journal Volume: 4; Journal Issue: 11; Journal ID: ISSN 2051-8153
Royal Society of Chemistry
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division; Canadian Light Source, Inc.; University of Wyoming; National Science Foundation of China
Country of Publication:
United States
OSTI Identifier: