Surface charge determination

The physicochemical characterization of a colloidal carrier is necessary because important characteristics, such as particle size, hydrophobicity, and surface charge, determine the biodistribution after administration [129-132]. Preparation conditions, such as the pH of the polymerization medium, monomer concentration, and surfactant concentration, can influence the physicochemical characteristics of the particles [60, 62, 64]. It is, therefore, essential to perform a comprehensive physicochemical characterization of nanoparticles, which has been reviewed by Magenheim and Benita [133]. 

Procedure. The solid used is a Merck alumina gel. The product is predominantly amorphous but its X-ray diffraction pattern exhibits small peaks characteristics of gibbsite. Its surface charge determined by counter-ions adsorption is reported in Fig. 4. Batch experiments were performed using 5 g/L solid contacted with ltr4 m uranyl carbonated solutions at pH 7... 

The interaction of a cation with a neutral oxide group results in the release of a proton, while the association of an anion results in the adsorption of a proton. Accordingly, the formation of a negative site from a neutral site involves the release of a proton and the formation of a positive site involves the adsorption of a proton. Therefore, the titratable surface charge determined by potentiometric titration is a measure of both the formation of surface-ion complexes and the ionization of surface functional groups, and... 

For surface charge determination, ARSL dispersions are diluted with filtered PBS pH 7.40 and their electrophoretic mobility is measured at 25°C by Photon Correlation Spectroscopy [PCS] (Zetasizer 5000, Malvern Instruments, UK). Finally, the zeta potential values of the dispersions are calculated by the instrument from their electrophoretic mobility, by application of the Smolowkovski equation. 

Zhang, Z. et al.. Electrodeposition of Ni-SiC nanocomposite coatings based on the surface charge determination of SiC nanoparticles. Bull. Electrochem., 22, 189, 2006. 

As an illustration of the direct surface charge determination, the results obtained on precipitated silica are shown in Eigure 19.1, where is plotted versus pH at four... 

The methods described above for the study of TCE are representative of the methods we are currently using to study the adsorption of a variety of organic molecules by clay mineral surfaces. We shall briefly summarize the results obtained so far in two other cases, one dealing with the adsorption of methylene blue to clays and the other dealing with a recalibration of the alkyl ammonium ion method for surface charge determination. In both of these studies, essentially the same computational techniques as those described above were used. 

Surface charge determination is of high importance in the study of oxide minerals. These materials usually show a strong dependence of the charge on pH, as already discussed in Chapter 5. Most oxide minerals present amphoteric surface OH groups able to undergo acid-base reactions, which can be represented as... 

Surface properties Surface charge affects the state of dispersion of the particles and is pH dependent Close to the iso-electric point, aggregation tends to occur. Surface charge determines adsorption of flocculants and dispersants. Surface hydrophobicity/philicity can be modified to make particles respond to flotation. 

In the considered model, electrostatic interaction between protons and metal surface charge determines the distributions of protons and electrostatic potential in the pore. These phenomena distinguish the present pore model from the gas- and electrolyte-filled single pore models pioneered by Srinivasan et al. (1967), Srinivasan and Hurwitz (1967) and De Levie (Levie, 1967). With the explicit consideration of the pore wall surface charge, the potential of zero charge of the catalyst material... 

Surface Charge Determines the Aggregation of Hemoglobin Subunits as Predicted by the Surface Free Energy M. Blank... 

SURFACE CHARGE DETERMINES THE AGGREGATION OF HEMOGLOBIN SUBUNITS AS PREDICTED BY THE SURFACE FREE ENERGY... 

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