Goethite adsorption

The primary anion studied in both the titration calorimetry7 and CIR-FTIR experiments reported here was the salicylate (2-hydroxybenzoate) ion (SAL). Acidity constants for salicylic acid are pK = 3.0 and pK = 13 (12), and the aqueous solubility of salicylic acid is 2.4 g/L, while that of NaSAL is 975 g/L. SAL has been shown to adsorb on both iron oxides (13) and aluminum oxides (14). Several other anions were also studied, and results for these anions are given as needed to illuminate certain features of the salicylate-goethite adsorption process. [Pg.143]

Duff MC, Amrhein C (1996) Uranium (VI) adsorption on goethite and soil in carbonates solutions. Soil Sei Soc Am 160 1393-1400... [Pg.570]

Boron is adsorbed on Fe/Al oxides (goethite and gibbsite) via an inner-sphere mechanism with shifts in zero point of charge (Goldberg et al., 1993). Boron adsorption on Fe/Al oxides increases from pH 3 to 6,... [Pg.138]

Arsenate is readily adsorbed to Fe, Mn and Al hydrous oxides similarly to phosphorus. Arsenate adsorption is primarily chemisorption onto positively charged oxides. Sorption decreases with increasing pH. Phosphate competes with arsenate sorption, while Cl, N03 and S04 do not significantly suppress arsenate sorption. Hydroxide is the most effective extractant for desorption of As species (arsenate) from oxide (goethite and amorphous Fe oxide) surfaces, while 0.5 M P04 is an extractant for arsenite desorption at low pH (Jackson and Miller, 2000). [Pg.139]

Barrow N.J., Gerth J., Brnmmer G.W. Reaction kinetics of the adsorption and desorption of nickel, zinc and cadmium by goethite. II Modelling the extent and rate of reaction. J Soil Sci 1989 40 437M50. [Pg.331]

Liu F, De Cristofaro A, Violante A (2001) Effect of pH phosphate and oxalate on the adsorption/desorption of arsenate on/from goethite. Soil Sci 166 197-208 Livesey NT, Huang PM (1981) Adsorption of arsenate by soils and its relation to selected properties and anions. Soil Sci 131 88-94 Manceau A (1995) The mechanism of anion adsorption on iron oxides Evidence for the bonding of arsenate tetrahedra on free Fe(0, OH)6 edges. Geochim Cosmochim Acta 59 3647-3653. [Pg.66]

Sun X, Doner, HE (1996) An investigation of arsenate and arsenite bonding structures on goethite by FTIR. Soil Sci 161 865-872 Sun X, Doner HE (1998) Adsorption and oxidation of arsenite on goethite. Soil Sci 163 278-287... [Pg.68]

Violante A, Krishnamurti GSR, Pigna M (2008) Mobility of trace elements in soil environments. In Violante A, Huang PM and Gadd G (eds) Wiley-JUPAC series on biophysico-chemical processes of metals and metalloids in soil environments. John Wiley Sons, Hoboken, USA Waltham AC, Eick MJ (2002) Kinetic of arsenic adsorption on goethite in the presence of sorbed silicic acid. Soil Sci Soc Am J 66 818-825 Waychunas GA, Fuller CC, Rea BA, Davis J (1996) Wide angle X-ray scattering (WAXS) study of two-line ferrihydrite structure Effect of arsenate sorption and counterion variation and comparison with EXAFS results. Geochim Cos-mochim Acta 60 1765-1781... [Pg.68]

Gold, chloride, adsorption, magnetite, goethite, alumina, titanium dioxide, hydrometallurgy... [Pg.1]

Berrodier, I., Farges, F., Benedetti, M., Winterer, M., Brown Jr, G. E., Deveughele, M. (2004). Adsorption mechanisms of trivalent gold on iron- and aluminum-(oxy)hydroxides. Part 1 X-ray absorption and Raman scattering spectroscopic studies of Au(III) adsorbed on ferrihydrite, goethite, and boehmite. Geochimica et Cosmochimica Acta, 68(14), 3019-3042. doi 10.1016/j.gca.2004.02.009... [Pg.9]

Direct in situ X ray (from synchroton radiation) adsorption measurements (EXAFS) (Hayes et al., 1987, Brown et al., 1989) permit the determination of adsorbed species to neighboring ions and to central ions on oxide surfaces in the presence of water. Such investigations showed, for example, that selenite is inner-spherically and selenate is outer-spherically bound to the central Fe(lll) ions of a goethite surface. It was also shown by this technique that Pb(II) is inner-spherically bound to 5-AI2O3 (Chisholm-Brause et al., 1989). [Pg.24]

For example the adsorption of F on goethite induces a shift in the titration curve (Fig. 2.10b) (Sigg and Stumm, 1981). [Pg.37]

Hayes and Leckie (1986) postulate on the basis of their pressure jump relaxation experiments on the adsorption-desorption of Pb2+ at the goethite-water interface the following mechanism ... [Pg.127]

A representative result of their data on Pb adsorption on goethite is given in Table 4.4. [Pg.127]

Adsorption of heavy metal ions to the surface of goethite and of natural particles... [Pg.373]

Mechanisms of Sorption Processes. Kinetic studies are valuable for hypothesizing mechanisms of reactions in homogeneous solution, but the interpretation of kinetic data for sorption processes is more difficult. Recently it has been shown that the mechanisms of very fast adsorption reactions may be interpreted from the results of chemical relaxation studies (25-27). Yasunaga and Ikeda (Chapter 12) summarize recent studies that have utilized relaxation techniques to examine the adsorption of cations and anions on hydrous oxide and aluminosilicate surfaces. Hayes and Leckie (Chapter 7) present new interpretations for the mechanism of lead ion adsorption by goethite. In both papers it is concluded that the kinetic and equilibrium adsorption data are consistent with the rate relationships derived from an interfacial model in which metal ions are located nearer to the surface than adsorbed counterions. [Pg.6]

Spectroscopic techniques may provide the least ambiguous methods for verification of actual sorption mechanisms. Zeltner et al. (Chapter 8) have applied FTIR (Fourier Transform Infrared) spectroscopy and microcalorimetric titrations in a study of the adsorption of salicylic acid by goethite these techniques provide new information on the structure of organic acid complexes formed at the goethite-water interface. Ambe et al. (Chapter 19) present the results of an emission Mossbauer spectroscopic study of sorbed Co(II) and Sb(V). Although Mossbauer spectroscopy can only be used for a few chemical elements, the technique provides detailed information about the molecular bonding of sorbed species and may be used to differentiate between adsorption and surface precipitation. [Pg.7]

Mechanism of Lead Ion Adsorption at the Goethite-Water Interface... [Pg.114]

Due to the fast kinetics of adsorption/desorption reactions of inorganic ions at the oxide/aqueous interface, few mechanistic studies have been completed that allow a description of the elementary processes occurring (half lives < 1 sec). Over the past five years, relaxation techniques have been utilized in studying fast reactions taking place at electrified interfaces (1-7). In this paper we illustrate the type of information that can be obtained by the pressure-jump method, using as an example a study of Pb2+ adsorption/desorption at the goethite/water interface. [Pg.114]

Based on the pressure-jump relaxation results reported here, the following mechanism is postulated for the adsorption/desorption of Pb2+ ion at the goethite/water interface (8) ... [Pg.114]

Figure 3. The dependence of Pbil r adsorption on goethite as a function of background electrolyte concentration.

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