ATR–FTIR Spectroscopic Investigation on Phosphate Adsorption Mechanisms at the Ferrihydrite–Water Interface

2001 ◽  
Vol 241 (2) ◽  
pp. 317-326 ◽  
Author(s):  
Yuji Arai ◽  
D.L. Sparks
Keyword(s):  
Spectroscopic Investigation ◽  
Phosphate Adsorption ◽  
Water Interface ◽  
Adsorption Mechanisms

Arsenate Adsorption Mechanisms at the Allophane−Water Interface

2005 ◽  
Vol 39 (8) ◽  
pp. 2537-2544 ◽  
Author(s):  
Yuji Arai ◽  
D. L. Sparks ◽  
J. A Davis
Keyword(s):  
Water Interface ◽  
Adsorption Mechanisms ◽  
Arsenate Adsorption

A spectroscopic investigation of phosphate adsorption onto iron oxides

1996 ◽  
Vol 14 (3) ◽  
pp. 1357-1361 ◽  
Author(s):  
M. G. Nooney ◽  
T. S. Murrell ◽  
J. S. Corneille ◽  
E. I. Rusert ◽  
L. R. Hossner ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Spectroscopic Investigation ◽  
Phosphate Adsorption

scholarly journals Infrared Spectroscopic Characterization of Phosphate Binding at the Goethite-Water Interface

2018 ◽  
Author(s):  
Ashour Ahmed ◽  
Stella Gypser ◽  
Peter Leinweber ◽  
Dirk Freese ◽  
Oliver Kühn
Keyword(s):  
Ir Spectra ◽  
Interaction Energy ◽  
Phosphate Adsorption ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Water Interface ◽  
Binding Mechanism ◽  
Phosphate Binding ◽  
Covalent Bonds ◽  
Surface Plane

<div><div><div><p>The interaction between phosphates and soil mineral surfaces, such as Fe- and Al-(oxyhydr)oxides, plays a crucial role in the P immobilization and thus its availability for plants. The reactions of phosphates with Fe-hydroxides and especially goethite have been studied extensively. But a molecular-level picture about the phosphate binding mechanism at the goethite-water interface is still lacking. Therefore, in the current contribution we have explored the molecular binding mechanism for the adsorbed phosphate at the goethite–water interface by performing sorption kinetics experiments for orthophosphate and characterizing the adsorbed species by FT-IR spectroscopy. In parallel, periodic DFT calculations have been performed to explore the interaction mechanism as well as to calculate the IR spectra for monodentate (M) and bidentate (B) orthophosphate complexes at two different goethite surface planes (010 and 100) in the presence of water. In general, our interaction energy results give evidence that the mono-protonated B phosphate complex is more favored to be formed at the goethite–water interface although the M motif could exist as a minor fraction. Moreover, it was found that water plays an important role in controlling the phosphate adsorption process at the goethite surfaces. The interfacial water molecules form H-bonds (HBs) with the phosphate as well as with the goethite surface atoms. Further, some water molecules form covalent bonds with goethite Fe atoms while others dissociate at the surface to protons and hydroxyl groups. The present theoretical assignment of IR spectra introduces a benchmark for characterizing experimental IR data for the adsorbed KH2PO4 species at the goethite–water interface. In particular, IR spectra of the mono-protonated (2O+1Fe) B complex at the 010 goethite surface plane and the M complex at the 100 goethite surface plane were found to be consistent with the experimental data. In order to explore the role of different abundancies of surface planes and binding motifs, IR spectra obtained from weighted averages have been analyzed. Results confirmed the above conclusions drawn from interaction energy calculations.</p></div></div></div>

scholarly journals Infrared Spectroscopic Characterization of Phosphate Binding at the Goethite-Water InterfaceUntitled Item

2018 ◽  
Author(s):  
Ashour Ahmed ◽  
Stella Gypser ◽  
Peter Leinweber ◽  
Dirk Freese ◽  
Oliver Kühn
Keyword(s):  
Ir Spectra ◽  
Interaction Energy ◽  
Phosphate Adsorption ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Water Interface ◽  
Binding Mechanism ◽  
Phosphate Binding ◽  
Covalent Bonds ◽  
Surface Plane

<div><div><div><p>The interaction between phosphates and soil mineral surfaces, such as Fe- and Al-(oxyhydr)oxides, plays a crucial role in the P immobilization and thus its availability for plants. The reactions of phosphates with Fe-hydroxides and especially goethite have been studied extensively. But a molecular-level picture about the phosphate binding mechanism at the goethite-water interface is still lacking. Therefore, in the current contribution we have explored the molecular binding mechanism for the adsorbed phosphate at the goethite–water interface by performing sorption kinetics experiments for orthophosphate and characterizing the adsorbed species by FT-IR spectroscopy. In parallel, periodic DFT calculations have been performed to explore the interaction mechanism as well as to calculate the IR spectra for monodentate (M) and bidentate (B) orthophosphate complexes at two different goethite surface planes (010 and 100) in the presence of water. In general, our interaction energy results give evidence that the mono-protonated B phosphate complex is more favored to be formed at the goethite–water interface although the M motif could exist as a minor fraction. Moreover, it was found that water plays an important role in controlling the phosphate adsorption process at the goethite surfaces. The interfacial water molecules form H-bonds (HBs) with the phosphate as well as with the goethite surface atoms. Further, some water molecules form covalent bonds with goethite Fe atoms while others dissociate at the surface to protons and hydroxyl groups. The present theoretical assignment of IR spectra introduces a benchmark for characterizing experimental IR data for the adsorbed KH2PO4 species at the goethite–water interface. In particular, IR spectra of the mono-protonated (2O+1Fe) B complex at the 010 goethite surface plane and the M complex at the 100 goethite surface plane were found to be consistent with the experimental data. In order to explore the role of different abundancies of surface planes and binding motifs, IR spectra obtained from weighted averages have been analyzed. Results confirmed the above conclusions drawn from interaction energy calculations.</p></div></div></div>

scholarly journals FT–IR Studies on Langmuir–Blodgett Films of Novel Phosphorus Amphiphiles: Spontaneous Polycondensation at the Air/Water Interface

2005 ◽  
Vol 2005 (6) ◽  
pp. 385-387
Author(s):  
Hai-Yan Wang ◽  
Yan-Mei Li ◽  
Yi Xiao ◽  
Yu-Fen Zhao ◽  
Li-Xin Wu
Keyword(s):  
Spectroscopic Investigation ◽  
Water Interface ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Ir Studies ◽  
Air Water Interface ◽  
Langmuir Blodgett Films ◽  
Ft Ir ◽  
Ir Spectroscopic

A series of amphiphilic N-(O,O-dihexadecyl)phosphorylamino acids were designed and synthesised, and the transmission FT–IR spectroscopic investigation of their Langmuir–Blodgett films (LB films) on CaF2 substrates indicates the spontaneous polycondensation at the air/water interface before the deposition.

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