University of Illinois Urbana-Champaign

Effects of phytic acid sorption on iron polymerization and at the ferrihydrite-water interface

Chen, Ai

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CHEN-THESIS-2019.pdf

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https://hdl.handle.net/2142/105146

Description

Title
Effects of phytic acid sorption on iron polymerization and at the ferrihydrite-water interface
Author(s)
Chen, Ai
Issue Date
2019-03-25
Director of Research (if dissertation) or Advisor (if thesis)
Arai, Yuji
Department of Study
Natural Res & Env Sci
Discipline
Natural Res & Env Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2019-08-23T20:44:35Z
Keyword(s)
  • phytic acid
  • sorption
  • ferrihydrite
  • NMR
  • XRD
  • SEM
Abstract
Phytic acid is the most predominant organic phosphorus species in soils. Its stability in soils is mainly due to its high affinity for soil colloids, especially Fe (oxyhydr)oxides. They have been acknowledged as mobile/reactive adsorbents for P in soil-water environments. Although several sorption mechanisms were proposed, it is not clear how multi phosphate groups of phytic acid contribute to the surface complexation and/or precipitation processes. In this study, sorption behavior of phytic acid in ferrihydrite was examined using experimental geochemistry, solution 31P nuclear magnetic resonance spectroscopy, X-ray diffraction and scanning electron microscopy. The results indicated inner-sphere surface complexation via P1,3 and P2 functional groups under both pH 5 and 8.5. Under alkaline pH, an additional P5 functional group became active. Coprecipitation experiments showed evidence of the formation of Fe(III)-phytate-like bulk precipitates when the initial phytic acid/Fe(III) molar ratio was high (0.45-0.5). At the low phytic acid/Fe(III) (<0.1), the formation of ferrihydrite was unaffected, but further transformation was still inhibited. The study suggests a new role of phytic acid in the formation of Fe oxyhydroxide minerals.
Graduation Semester
2019-05
Type of Resource
text
Permalink
http://hdl.handle.net/2142/105146
Copyright and License Information
Copyright 2019 Ai Chen

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Graduate Theses and Dissertations at Illinois
Dissertations and Theses - Natural Resources and Environmental Sciences