Goethite characterization

Zeitner, W. A., E. C. Yost, M. L. Machesky, M. I. Tejedor-Tejedor, and M. A. Anderson (1986), "Characterization of Anion Binding on Goethite Using Titration Calorimetry and Cylindrical Internal Reflec-tion-Fourier Transform Infrared Spectroscopy", in J. A. Davis and K. F. Hayes, Eds., Geochemical Processes at Mineral Surfaces, Am. Chem. Soc., Washington, 142-161. 

Characterization of Anion Binding on Goethite Using Titration Calorimetry and Cylindrical Internal Reflection-Fourier Transform Infrared Spectroscopy... 

Schwertmann, 1993). Such soils are characterized by a hydraulic conductivity somewhere in the profile which is too low to cope with the high rainfall, so that all pores will be filled with water for certain periods of time (see above). In this case, the oxygen supply is limited by the low level of O2 dissolved in the soil water (46 mg O2 at 25 °C) and reduction of Mn-oxides, nitrate and Fe oxides sets in. Soils containing Fe oxides are, therefore, redox-buffered (poised). The redox titration curve (Fig. 16.14) of a soil with 23 g kg Fe as Fe oxides shows buffering at two different pe -1- pH levels, one at ca. 11 and another at ca. 9, which indicate the presence of a more reducible (e. g. ferrihydrite) and a less reducible (e. g. goethite) Fe oxide, respectively, in accordance with their different solubilities (see Chap. 9). 

Outer-sphere adsorption of Pb(ll)EDTA on goethite. Geochim. Cosmochim. Acta 63(19/20) 2957-2969 Bargar, J.R. Reitmeyer, R. Davis, J.A. (1999) Spectroscopic confirmation of uranium(Vl)-carbonato adsorption complexes on hematite. Environ. Sci. Techn. 33 2481-2483 Bargar, J.R. Reitmeyer, R. Lenhart, J.J. Davis, J.A. (2000) Characterization of U(Vl)-car-bonato ternary complexes on hematite EX-AFS and electrophoretic mobility measurements. Geochim. Cosmochim. Acta 64 ... 

Goodman, B.A. Cheshire, M.V. (1987) Characterization of iron-fulvic acid complexes using Mossbauer and FPR spectroscopy. Sci. Total Fnviron. 62 229-240 Goodman, B.A. Lewis, D.G. (1981) Mossbauer spectra of aluminous goethites (a-FeOOH). J. Soil Sci. 32 351-363 Goodman, B.A. (1988) An introduction to physical and chemical principles. In Studd, J.W. Goodman, B.A. Schwertmann, U. (eds.) Iron in soils and day minerals. D. Reidel Publ. Co., Dordrecht, Holland, NATO ASI Sen 217 19-36... 

Tejedor-Tejedor, M.L Yost, E.C. Anderson, M.C. (1990a) Characterization of benzoic acid and phenolic complexes at the goethite/ aqueous solution interface using cylindrical internal reflectance Fourier transform infrared spectroscopy. Part 5 Methodology. Langmuir 6 979-987... 

Zeltner,W.A. Yost, E.C. Machesky M.L. Teje-dor-Tejedor, M.I. Anderson, M.A. (1986) Characterization of anion adsorption on goethite using titration calorimetry and CIR-ETIR. In Davis, J.A. Hayes, K.E. (eds.) Geochemical processes at mineral surfaces. 

Yost, E. C.,Tejedor-Tejedor, M. I., and Anderson, M. A. (1990). In situ CIR-FTIR characterization of salicylate complexes at the goethite/aqueous solution interface. Environ. Sci. Technol. 24,822-828. 

The conversion of goethite or iron hydroxides into hematite has been investigated experimentally in a great number of works, and the results obtained are rather diverse. Even at room temperature hematite often forms along with goethite, especially in acid and neutral environments. Apparently both these phases are characterized by similar thermodynamic properties and the AGj value of the reaction of dehydration of a-FeOOH at moderate temperatures is not large. 

Surface analytical techniques. A variety of spectroscopic methods have been used to characterize the nature of adsorbed species at the solid-water interface in natural and experimental systems (Brown et al, 1999). Surface spectroscopy techniques such as extended X-ray absorption fine structure spectroscopy (EXAFS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) have been used to characterize complexes of fission products, thorium, uranium, plutonium, and uranium sorbed onto silicates, goethite, clays, and microbes (Chisholm-Brause et al, 1992, 1994 Dent et al, 1992 Combes et al, 1992 Bargar et al, 2000 Brown and Sturchio, 2002). A recent overview of the theory and applications of synchrotron radiation to the analysis of the surfaces of soils, amorphous materials, rocks, and organic matter in low-temperature geochemistry and environmental science can be found in Fenter et al (2002). 

Lepidocrocite is generally less widespread than its polymorph, goethite, but it does occur frequently as orange accumulations in certain environments. These are characterized by the presence of Fe from which lepidocrocite forms by oxidation. The presence of this mineral, therefore, in-... 

Figure 10 illustrates that Crw effectively inhibits the proton-promoted dissolution of goethite. Cr(III) adsorbs even at low pH and, as bi- or polynuclear surface complexes, blocks surface sites from being protonated. Furthermore, isomorphically substituted Cr3+ ions, characterized by an extremely low water-exchange rate, impart inertness to the surface lattice bonds. 

Kosmulski, M. et al.. Synthesis and characterization of goethite and goethite-hematite, composite Experimental study and literature survey, Adv. Colloid Interf. Sci. 103, 57, 2003. 

Zeltner, W.A. et al.. Characterization of anion binding on goethite using titration calorimetry and cylindrical internal reflection-Fourier transform infrared spectroscopy, ACS Symp. Ser., 323, 142, 1986. 

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