ADSORPTION-KINETICS OF VANADYL(IV) AND CHROMIUM(III) TO ALUMINUM-OXIDE - EVIDENCE FOR A 2-STEP MECHANISM

被引：54

作者：

WEHRLI, B

IBRIC, S

STUMM, W

机构：

[1] Institute for Water Resources and Water Pollution Control (EAWAG), Swiss Federal Institute of Technology (ETH), Zürich

来源：

COLLOIDS AND SURFACES | 1990年 / 51卷

关键词：

D O I：

10.1016/0166-6622(90)80133-O

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Adsorption of V (IV) and Cr (III) on δ-Al2O3 can be interpreted in terms of a surface complex formation model. The relative inertness of VO2+ and Cr3+ aqueous ions with regard to ligand exchange reactions is reflected in the adsorption kinetics of these ions. Adsorption occurs in two steps, a relatively fast one and a slow one. The slow step is characterized by a pH dependence of the adsorption of VO (OH)+ and Cr(OH)2+, respectively. The adsorption rates of these hydroxy species on a surface (3.1·10-3M surface OH ligands) are given by k*2=3.91·10-3s-1 for VO (OH)+ and k*2=1.75·10-6s-1 for Cr (OH)2+. (At pH 4, this corresponds to half-lifes of 4 and 110 h for VO (OH)+ and Cr (OH)2+, respectively). The adsorption rate of VO (OH)+ is, within a factor 3, equal to that predicted by considering the coulombic interaction, and an intrinsic adsorption rate estimated with the help of a linear free energy relation between adsorption rate and the rate of water exchange based on the data of Hachiya et al., J. Phys. Chem., 88 (1984) 27. © 1990.

引用

页码：77 / 88

页数：12

共 24 条

[1]

Astumian, Schelly, J. Am. Chem. Soc., 106, (1984)

[2]

Baes, Mesmer, The Hydrolysis of Cations, (1976)

[3]

Espenson, Inorg. Chem., 8, (1969)

[4]

Furrer, Stumm, The coordination chemistry of weathering: I. Dissolution kinetics of δ-Al2O3 and BeO, Geochimica et Cosmochimica Acta, 50, (1986)

[5]

Goncalves, Sigg, Stumm, Voltammetric methods for distinguishing between dissolved and particulate metal ion concentrations in the presence of hydrous oxides. A case study on lead(II), Environmental Science & Technology, 19, (1985)

[6]

Hachiya, Sasaki, Ikeda, Mikami, Yasunaga, J. Phys. Chem., 88, (1984)

[7]

Hunt, Friedman, Aquo Complexes of Metal Ions, Prog. Inorg. Chem., 30, (1983)

[8]

Kummert, Stumm, Colloid Interface Sci., 75, (1980)

[9]

Langford, Gray, Ligand Substitution Processes, (1966)

[10]

Leckie, Appleton, Ball, Hayes, Honeyman, Report 910.1 of the Electric Power Research Institute, (1984)

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