On the Anomalous Adsorption of [Pd(Edta)]**2- at the Water/Goethite Interface: Spectroscopic Evidence for Two Types of Surface Complexes
The structure of palladium(II) ethylenediaminetetraacetate (edta) in aqueous solutions and its adsorption on the surface of goethite ({alpha}-FeOOH) were studied using extended X-ray absorption fine structure spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy. The obtained results show that in aqueous solutions, Pd-edta exists as a 1:1 complex, [Pd(edta)]{sup 2-}, with edta acting as a quadridentate ligand. On the surface of goethite, [Pd(edta)]{sup 2-} forms two different types of complexes over a pH range of 3.40-8.12. At pH < 5, [Pd(edta)]{sup 2-} adsorbs as an outer-sphere species with possible hydrogen bonding. At higher pH values, the formation of inner-sphere complexes of the cation-type sets in after a cleavage of one glycinate ring and the formation of an (edta)Pd-O-Fe linkage.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 953140
- Report Number(s):
- SLAC-REPRINT-2009-144; LANGD5; TRN: US200914%%340
- Journal Information:
- Langmuir 24:483,2008, Vol. 24, Issue 2; ISSN 0743-7463
- Country of Publication:
- United States
- Language:
- English
Similar Records
Outer-sphere adsorption of Pb(II)EDTA on goethite
Outer Sphere Adsorption of Pb(II)EDTA on Goethite