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

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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2019

Author dc:creator

• Chen, Ai

Contributors dc:contributor

• Arai, Yuji

• phytic acid
• sorption
• ferrihydrite
• NMR
• XRD
• SEM

Statement dc:rights

• Copyright 2019 Ai Chen

Language dc:language

en

Handle dc:identifier

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

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/105146