Aqueous surface chemistry of oxides

Parks, G. A. (1967), "Aqueous Surface Chemistry of Oxides and Complex Oxide Minerals Isoelectric Point and Zero Point of Charge," in Equilibrium Concepts in Natural Water Systems, Advances in Chemistry Series, No. 67, American Chemical Society, Washington, DC. 

Aqueous Surface Chemistry of Oxides and Complex Oxide Minerals... 

Parks, G.A. 1967. Aqueous surface chemistry of oxides and complex oxide minerals Isoelectric point and zero point of charge, p. 121-160. In R.F. Gould (ed.) Equilibrium concepts in natural water systems. Vol. 67. Advances in Chemistry Series, ACS, Washington, DC. 

In the present study the surface chemistry of birnessite and of birnessite following the interaction with aqueous solutions of cobalt(II) and cobalt(III) amine complexes as a function of pH has been investigated using two surface sensitive spectroscopic techniques. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The significant contribution that such an investigation can provide rests in the information obtained regarding the chemical nature of the neat metal oxide and of the metal oxide/metal ion adsorbate surfaces, within about the top 50 of the material surface. The chemical... 

Preparation of non-aqueous dispersions of colloidal silver by phase transfer has been described [51] and advantage has been taken to form monodisperse, 7.0-nm-diameter silver particles by simultaneously reducing Ag+ and partially oxidizing Agn particles (radiolytic push-pull reduction method) [52]. The surface chemistry of nanosized silver particles has continued to receive attention [53, 54],... 

They studied the chemistry of oxidized Si(lll) surfaces treated at two concentrations of the silane in trichloroethylene solution using angle-dependent X-ray photoelectron spectroscopy (XPS or ESCA). Although these are non-aqueous adsorption studies, sufficient surface silanol or adsorbed water is present for complete hydrolysis to occur because no trace of chlorine is seen in the XPS spectra. The two concentrations studied were 1% v/v, termed saturated, and <1/400% v/v, termed dilute. They lead to two distinct types of molecular bonding to the surface. C( 1 s) XPS spectra of these two situations are shown in Fig. 3. 

The majority of studies on surface chemistry of ion-bombarded samples are concerned with the oxidation arid corrosion of materials. One part of the experiments covers the corrosion and oxidation in gaseous atmosphere such as air or oxygen at normal or high temperatures. The other, smaller, part deals with aqueous corrosion, in particular with the dissolution of metals and the formation of passivating layers in aqueous solutions. The interest in this subject found its expression in two conferences in 1975 and in 1978 ... 

The phenomena presented in this book were discussed in many reviews. For example, Schwarz [13] discussed methods used to characterize the acid base properties of catalysts. The review on sorption on solid - aqueous solution interface by Parks [14] includes also principles of surface science. The book Environmental Chemistry of Aluminum edited by Sposito reviews the solution and surface chemistry of aluminum compounds. Chapter 3 [15] provides thermochemical data for aluminum compounds. Chapter 5 [16] lists the points of zero charge of aluminum oxides, oxohydroxides and hydroxides with many references on adsorption of metal cations and various anions on these materials. Unlike the present book, which is confined to sorption from solution at room temperature, publications on coprecipitation and adsorption from gas phase or at elevated temperatures are also cited there. Brown et al. [17] reviewed on dry and wet surface chemistry of metal oxides. Stumm [18] reviewed sorption of ions on iron and aluminum oxides. The review by Schindler and Stumm [19] is devoted to surface charging and specific adsorption on oxides. Schindler [19] published a review on similar topic in German. Many other reviews related to specific topics are cited in respective chapters. 

The second major aspect of the surface chemistry of chromia-alumina that has to be considered is the acidic nature of its surface. The exact chemical nature of the acid sites of solid oxide catalysts such as alumina or silica-alumina has been a subject of considerable research and speculation for a number of years, yet despite these efforts a fully satisfactory chemical description of catalyst acidity has not been obtained. Nevertheless, in the case of chromia-alumina, there is good evidence for the existence of acid sites of one kind or another on the surface. Voltz and Weller (29), for example, studied the chemisorption of quinoline on chromia-alumina, with and without potassium promotion, and at the same time measured their titrable acidities in aqueous suspensions. Both methods indicated that chromia-alumina was acidic, and that the addition of potassium decreased the acidity. This observation was supported by the fact that the double bond isomerization of 1-pentene, normally an acid-catalyzed reaction, proceeded quite readily over pure chromia-alumina, but less readily over a chromia-alumina treated with potassium. 

We have little direct in situ (microscopic) information on the specific adsorption of charged species (ions) at the oxide/aqueous solution interface in strong acid media despite the fact that the role of the surface chemistry of the metal (hydr)oxide/solution interface is well documented [12, 13, 14, 15, 16]. 

Casey WH (1991) On the relative dissolution rates of some oxide and orthosilicate minerals. J Colloid Interface Sci 146 586-589 Casey WH, Westrich HR (1992) Control of dissolution rates of orthosilicate minerals by local metal-oxygen bonds. Nature 355 157-159 Casey WH, Carr MJ, Graham RA (1988a) Crystal defects and the dissolution kinetics of rutile. Geochim Cosmochim Acta, 52 1545-1556 Casey WH, Westrich HR, Arnold GW (1988b) The surface chemistry of labradorite feldspar reacted with aqueous solutions at pH = 2, 3 and 12. Geochim Cosmochim Acta 52 2795-2807... 

Surface Oraanometallic Chemistry of Hvdroauinone. Previous studies (2) have established that the interaction of aqueous HQ with smooth polycrystalline Pt is concentration-dependent. Below 0.1 m M, HQ undergoes spontaneous oxidation to form a chemisorbed monolayer of flat-oriented (ne) benzoquinone (BQ) similar to that in the homogeneous coordination of benzoquinone to tris (triethylphosphine) Pt (0) (2) ... 

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