Surface acidic functional groups

The surface area, the pore size, and the carbon yield are greatly influenced by oxidizing gas, heat-treatment temperature, and activation time. In addition, the oxidative activation introduced the surface acidic functional groups (SAFGs) on the pore surfaces of the carbon. The amounts of the SAFGs can be also controlled by... 

Yoshida and co-workers [161] studied the relationship between the EDL properties in an organic electrolyte solution and the concentration of surface acidic groups of phenolic resins-based activated carbon fibres. The authors reported that EDL capacitors with high capacitance and low leakage current were obtained with ACF that showed an extremely low concentration of surface acidic functional groups per unit surface ar ... 

Standard deviation of the distribution variables Surface acidic functional group Saturated calomel electrode Scanning electron microscopy Single-probe... 

Yoshida, A., I. Tanahashi, and A. Nishino. 1990. Effect of concentration of surface acidic functional groups on electric double-layer properties of activated carbon fibers. Carbon 28 611-615. 

Crocidolite In vitro Surface iron after reduction to Fe" and chelation by citrate Corresponding to decrements in surface F, thiobarbiturate-reactive products and HO. diminished. Deferoxamine provides similar results by chelating Fe. Ghio etal. 1992 Surface acidic functional groups... 

Once a metal surface has been conditioned by one of the above methods, a coupling agent composed of a bifimctional acid—methacrylate similar to a dentin adhesive is appHed. This coupling material is usually suppHed as a solvent solution that is painted over the conditioned metal surface. The acidic functional group of the coupling molecule interacts with the metal oxide surface while the methacrylate functional group of the molecule copolymerizes with the resin cement or restorative material placed over it (266,267). 

Generally, the interaction of polar analytes with the packing is rather weak due to the hydrophilic polyhydroxy functions on the surface of the packing. However, small amounts of acidic functional groups are present on the surface of the packing. The influence of these functional groups can be suppressed easily with the use of salts in the mobile phase. 

Abstracting from the complexity of the real systems, there is one common property of all natural particles. Their surfaces contain functional groups which can interact with H+, OH and metal ions and - if Lewis acid sites, e.g., =AI and =Fe, are available on the surface - with ligands. Many inorganic solids (oxidesQand silicates) contain hydroxo groups carbonates and sulfides expose -C-oh,-c oh, MeOH and -SH groups, respectively. While the interaction of alkaline and earth-alkaline ions... 

Electrostatic discrete functional group models. The development of charge on the surface of the humic macromolecule decreases the tendency to dissociate protons from the acid functional groups. To overcome this problem an electrostatic correction factor is introduced into the acid dissociation and complexation constants. This is similar to the approach adopted for the SCMs for inorganic surfaces. 

Oiganic colloids (mainly humic substances) also possess large specific surfaces and are generally negatively charged due to the acidic functional groups that tend to dissociate or polarize. Examples of such groups include carboxyls (R-COOH), quinones (-Ar=0), phenols (-Ar-OH), and enols (R-CH=CH-OH). (See Section 5.4.2 for a more complete discussion of humic substances.)... 

The measurement of acidity in paper documents with cold- and hot-water extraction frequently distorts and damages the paper fibers and printing inks. Many paper conservators and museum curators have long desired a reliable and rapid method for the detection of acidity of paper documents in a nondestructive manner so that they can determine the acidity routinely to screen out valuable book documents for deacidification or other necessary preservation treatments. The objective of this chapter is to introduce two spectroscopic techniques, namely, Fourier transform IR spectroscopy (FTIR) and electron spectroscopy for chemical analysis (ESCA), for chemical analysis of paper surfaces. The effectiveness of these techniques in analyzing and determining the presence of acidic functional groups on paper documents is demonstrated. 

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