Metal ions, sorption

Hayes, K. F. Katz, L. E. 1996. Application of X-ray absorption spectroscopy for surface complexation modelling of metal ion sorption. In Brady, P. V. (ed) Physics and Chemistry of Mineral Surfaces. CRC Press, Boca Raton, 147-223. 

Polyphosphates also play a role in the chemistry of natural metal oxides. For example, if the concentration of polyphosphates is smaller than that needed to saturate the available sites of a solid oxide surface, their presence enhances the sorption of surrounding metal ions by contrast, if their concentration exceeds that needed to saturate the surface, their presence decreases metal ion sorption due to two effects ... 

Cecchi, T., Pucciarelli, F., and Passamonti, P. Influence of metal ions sorption onto a styrene-divinylbenzene CIS stationary phase on the HPLC of metal chelating analytes. J. Liq. Chwmatogr. Rel. Technol. 1999, 22, 2467-2481. 

Lamb, J.D. and Nazarenko, A.Y., Selective metal ion sorption and transport using polymer inclusion membrane containing dicyclo-hexano 18-crown-6. Sep. Sci. Tech., 1997, 32 2749-2764. 

L]o is known for solution studies, and as regards the surface the information on the amount and nature of adsorption sites is mostly absent. The methods for determining of their number by interaction with certain substances including a titration and evaluation of capacity by metal ion sorption are also based finally on surface equilibria and hence require account of equilibrium (1) and an equation of a type (3). For example, in the case of proton adsorption Eq. (3) has the following form ... 

Hayes and Katz [47] reviewed application of X-ray absorption spectroscopy in studies of metal ion sorption. 

Chin, Ch.J.. Yiacoumi. S.. and Tsoui is. C., Influence of metal ion sorption on colloidal surface forces measured by atomic force microscopy. Environ. Sci. Technol., 36, 343, 2002. 

Guibal, E. et al., Apphcation of silica gel to metal ion sorption Static and dynamic removal of uranyl ions, Environ.TechnoL, 16, 101, 1995. 

Inoue, Y. et al.. Mechanism of metal-ion sorption on hydrous metal oxides, J. Radioanal. Nucl. Chem., 124, 361, 1988,... 

Konishi S. Binary metal-ion sorption during permeation through chelating porous membranes. J Membr Sci 1996 111 1-6. 

Table 7-2. TLM parameters and potential metal ion sorption reactions.

A number of different surface complexation models have been applied to describe and predict divalent metal ion sorption data over the past 20 to 30 yr. All of Ihe models incorporate surface acidity and the formation of metal ion complexes with surface hydroxyl groups via equilibrium mass law expressions such at those presented in Tabic 7-2. In addition, each model employs a description of the elec-Irical double layer lo correcl for electrostatic effects at the mineral/water interface (as shown in Fig. 7 4 lor (he triple layer model and described in Table 7-3). These... 

Modeling divalent metal ion sorption requires estimation of the proton stoichiometry (the number of protons released per metal ion sorbed), the type of surface complex (inner or outer sphere) formed, and the formation constants for each reaction selected. Table 7-2 presents a list of various reactions that may be incorporated into the TLM. Because a variety of combinations of different sorption reactions and constants may fit various aspects of the sorption data equally well (see, e.g., Westall Hohl, 1980 Hayes et al., 1991 Katz Hayes, 1995a), protocols are needed to insure the best choice of reactions and a more universally accepted set of guidelines to allow reproducibility from one laboratory to another. The strategy used in modeling Co(II) sorption to a-Al203 involved ... 

Analysis of the predictive capabilities of the ionic-strength dependence for valid sets of surface acidity parameters determined in step 1, and selection of optimal SCM parameters sets based on metal ion sorption data fits. 

FITEQL (Westall. IW2), a least-squares, fitting program, was used to lind optimum SCM parameter values f rom sets of titration or metal ion sorption data. 

What are some of the most important findings from these XAFS studies of metal ion sorption processes One is the discovery that metal ion complexes at mineral/water interfaces are often different from those in bulk aqueous solutions. These differences include higher degrees of hydrolysis and different first-shell coordination environments (e.g., ( ) surface complexes Bargar et al. 1997a), and a higher proportion of multinuclear complexes (e.g., ( ) and ( ) surface complexes on alumina Chisholm-Brause et al. 1990a Fitts et al. 2000) for surface complexes vs. solution complexes. These differences are likely related to differences in the properties of water at interfaces vs. in bulk solutions (see earlier... 

S. Konishi, K. Saito, S. Furusaki and T. Sugo, Binary Metal-Ion Sorption during Permeation through Chelating Porous Membranes, J. Membrane Sci.,... 

In the case of chitosan derivatives, noble metal ions are sorbed according to several kinetic models based on pure sorption, pure reduction and dual sorption-reduction mechanisms [149, 150]. Moreover, the optimum acid pH for noble metal ions sorption depends on the metal. For platinum and palladium, it was equal to 2. For CS cross-linked by glutaraldehyde (CS-GA) for... 

Efendiev, A.A. Kabanov, V.A. Selective polymer complexons prearranged for metal ions sorption. Pure Appl. Chem. 1982, 54, 2077-2092. 

B Singh et al, Metal ion sorption and swelling studies of psyllium and acrylic acid based hydrogels , Carbohydrate Polymers, 2006 64 50-56. 

Metal ions sorption by 2-pyridine carboxaldehyde phe-nylhydrazone supported by chemical binding on a silica surface were confirmed to the Langmuir isotherm. The modified phase was used and applied as a metal-ion extractant for determination of trace amounts of iron, cobalt, nickel, and copper. The relative orders of the Langmuir constants K and the column retention capacity factors K for the four transition metal ions are the same as the natural order of the stabihty constants for their metal chelates Fe(II) < Co(II) < Ni(II) < Cu(II). The structure is given in Scheme 5. 

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