Surface Chemistry of Oxides

Structure of Fumed Titania and Silica/Titania and Influence of the Nature of Surface Sites on Interaction with Water

“…This effect potential and the isoelectric point (IEP) values can depend can be caused by the influence of the B-site dissociation on a method of the sample production, e.g., IEP for rutile on the zeta potential and by the formation of agglomerates pH Å 7 (68), 5.4 (6), 5.6 (69) and for anatase pH Å 4.0 ( D ef above 15 mm) for SA in aqueous suspension ( Fig. 8 ) (68), 6.4 (6), 6.1 (69). Therefore, synthesis technique and as silica aggregates ( 0.1 -0.2 mm) can cover the alumina production conditions should be the same for correct comphases, which have different IEP and charge distribution parison of mixed and original oxides.…”

Fe3O4/multi-walled carbon nanotubes as an efficient catalyst for catalytic ozonation of p-hydroxybenzoic acid

“…It can be seen that p-HBA was slightly removed by adsorption at all tested pH conditions, and the absorption capacity decreased with increase in pH. The basic sites (Xing et al 2014) and charged surface (Yang et al 2014) have influence on chemisorption, and the charged surface can be determined by the pH of solution and pH pzc of catalyst (Parfiti 1976;Usharani et al 2012). According to our research, the pH pzc of prepared Fe 3 O 4 /MWCNTs was in acid range (3.43).…”

Interaction between carboxylic modifiers and nanodispersed aluminium

“…Using thermal desorption mass spectrometry, the presence of water and traces of hydrocarbons was revealed on the surface of ultradispersed aluminium, which being removed by heating of powder up to 100 • C. Intense evolution of water (M/z 18) at 30-400 • C is associated with the destruction of hydrating surface shell containing both physically and chemically adsorbed molecules whose acid-base properties depend on crystallographic features of metal surface [1,2]. The presence of hydrocarbon admixtures on the surface of aluminum synthesized in the arc discharge is probably related to the storage of freshly formed dispersion in benzine [17].…”

“…This results in the formation of oxide film on the metal surface and the physical and chemical binding of the water molecules to the surface [1,2]. Studies of the surface chemistry of aluminum and its oxide [1][2][3][4] made it possible to establish that the adsorption sites for various compounds are the coordination-unsaturated surface ions of aluminum, oxygen, and OH groups with various degree of acidity. In this connection, pure aluminum and its oxide can adsorb protic and aprotic acids and bases to form chemical and physical bonds [1][2][3][4][5][6].…”

“…Studies of the surface chemistry of aluminum and its oxide [1][2][3][4] made it possible to establish that the adsorption sites for various compounds are the coordination-unsaturated surface ions of aluminum, oxygen, and OH groups with various degree of acidity. In this connection, pure aluminum and its oxide can adsorb protic and aprotic acids and bases to form chemical and physical bonds [1][2][3][4][5][6]. It was revealed that short-and long-chain carboxylic acids with donor-acceptor properties can be chemisorbed on aprotic sites or OH groups of the surface or simultaneously on these both sites to form different carboxylates (monodentate, bidentate, and chelate forms) [4][5][6][7][8][9].…”