Acids adsorption potentials

As shown in Figure 4, the increase in adsorption of acetic acid on Pt(lll) occurs in the potential range of 0.15 to 0.3 V, which roughly coincides with position of the current-potential peak of the voltammogram recorded in the same solution. An interdependence can thus be sought between acetic acid adsorption... 

Li et al. [278] have studied adsorption of L-phenylalanine at Au(lll) electrodes using electrochemical and subtractively normalized interfacial FTIR methods. It has been found that the adsorbed molecules change their orientation with the electrode potential. At a negatively charged surface, the compound was predominantly adsorbed in the neutral form of the amino acid. At potentials positive with respect to pzc, L-phenylalanine was adsorbed predominantly as zwitterion with —GOO ... 

Waszczuk etal. [173] have performed radiometric and voltammetric studies of benzoic acid adsorption on a pc-Ag electrode in contact with 0.1 M HCIO4 solution. The electrodes were obtained by electroplating Ag black onto a vacuum-deposited silver substrate. Benzoic acid appeared to be surface active in the entire range of potentials available at Ag in aqueous solutions. Adsorption of benzoic acid increased as the potential became more positive and this surface process was... 

Sander and Henze [50] have performed ac investigations of the adsorption potential of metal complexes at Hg electrode. Later, Sander etal. [51] have studied electrosorption of chromium - diethylenetriaminepentaacetic acid (DTPA) on mercury in 0.1 M acetate buffer at pH 6.2 using a drop-time method. The changes in the interfacial activity of the Cr(III)-DTPA complex with the bulk concentration obeyed the Frumkin adsorption isotherm. 

Fig. 6.117. Adsorption isotherms for various organic species on platinum in 0.01 N HCI solution, obtained with the radiotracer technique valeric acid (a), butanol ( ), benzoic acid (a), naphtoic acid ( ), naphtol (O). All the data are taken at the maximum adsorption potential. (Reprinted from J. Jeng, dissertation, Texas A M University, 1991.)...

Experimental Activation Energies 1 e Bond Energies of Atoms in the Reacting Molecules with the Catalyst Qak Adsorption Potentials q and the Heights of the Potential Barriers E kg. cat./mole on Chromias of Different Methods of Preparation-, the Subscripts Designate 1—Dehydrogenation of Hydrocarbons, II—Dehydrogenation of Alcohols and Acids, III—Dehydration of Alcohols ... 

Many industrial organic acids can be produced by fermentation, such as acetic, citric, and lactic acids. Succinic acid is a dicarboxylic acid of potential industrial interest as a platform chemical (1-3). Separation and purification of succinic acid by adsorption was tested to replace current precipitation methods and their associated waste disposal problems. Succinic acid is a valuable intermediate value chemical with a moderate market. For succinic acid to have an economic and energy impact, it will need to become a commodity chemical intermediate with a much lower price. This target price hasbeen estimated to be between 0.22 and 0.30 / lb ( 0.48- 0.66/kg) and is potentially achievable with advanced technology (1). At this price, succinic acid can be catalytically upgraded into other higher valued chemicals suchastetrahydrofuran, 1,4-butanediol, y-butyrolactone, 2-pyrrolidinone, and N-methylpyrrolidinone. 

At pH 0.23 only one strong negative band at 1055 cm is observed at low potentials. A second band centered at 1110cm is developed at more anodic potentials (Fig. 58 b). The data from Habib and Bockris [138] also show a small band at 1074 cm , for adsorbed phosphoric acid. The potential dependence of the band intensities fits very well to radiotracer results on the adsorption of phosphoric acid in strongly acidic medium [160]. 

The characteristic curves of zeolites Y exchanged with alkaline cations are shown in Figure 8. In these cases, the same concentration of cations exists in the zeolite but with quite different polarising power (i.e., ratio between charge and cation radius). It is observed that by increasing the polarising power of the cations (i.e., from K to Li ), which results in an increase of the acidity of the zeolites, the negative deviation of the characteristic curve starts at lower adsorption potentials. 

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