An application of the microelectrophoresis method to the study of the surface properties of insoluble oxides

Abstract

The variation with pH of the electrophoretic mobility of suspended particles has been determined for Fe2O3, TiO2, SnO2, SiO2, Al2O3, and for a number of synthetic aluminosilicates. The properties of the natural substances have been compared with those of synthetic materials before and after ignition at high temperatures. In general, the dehydration and recrystallization caused by ignition of the precipitated materials tend to produce surfaces resembling those of the natural crystals.

Ultrasonic vibration potential and point of zero charge of some rare earth oxides in water

“…Table 1 summarizes the point of zero charge for a series of metal oxides. The value of Al 2 O 3 as reference seemed to be consistent with those of the previous reports [4][5][6][7][8]. The measured data of p.z.c.…”

“…The measured data of p.z.c. for Al 2 O 3 were 6.7 [4], 8.4 [5], 9.1 [6] and 9.4 [7], depending on the preparation of powder and colloid with electrolytes. Since Al 2 O 3 shows both acidic and basic properties on the surface site, a procedure such as pre-heat treatment can affect on resultant p.z.c.…”

Filtration-Rate Technique for Determining Zero Point of Charge of Iron Oxides

“…Electrokinetic methods include microelectrophoretic and streaming potential techniques (Johansen and Buchanan, 1957). Potentiometric titration is the equilibrium electrochemical technique most often used to determine the ZPC of oxides and other materials (Bolt, 1957;Parks and de Bruyn, 1962).…”

Inorganic particulates in removal of heavy metal toxic ions

“…On the other hand, tin oxide behaves both as a cation and an anion exchanger [18,39] in a wide pH range. Johansen and Buchanan reported that the pH at zero point charge (p zpc ) of tin oxide is 4.5 [40]. A systematic pH-dependence study made for the removal of Cr(IV) by tin oxide reports that the maximum uptake of Cr(IV) was observed at pH ca.…”