Adsorption peak

Kakiuehi et al. [84] studied the adsorption properties of two types of nonionic surfactants, sorbitan fatty acid esters and sucrose alkanoate, at the water-nitrobenzene interface. These surfactants lower the interfacial capacity in the range of the applied potential with no sign of desorption. On the other hand, the remarkable adsorption-desorption capacity peak analogous to the adsorption peak seen for organic molecules at the mercury-electrolyte interface can be observed in the presence of ionic surfactants, such as triazine dye ligands for proteins [85]. 

Reduction in charge under hydrogen adsorption peaks. 

The basicity of OLOA 1200 has been evidenced by its interaction with the oil-soluble acidic indicator dye, Brom Phenol Magenta E (EK 6810) which is normally yellow but turns blue and then magenta with increasing bacicity. The acidic form has an adsorption peak at 390 nm, the basic at 610 nm, and the isobestic point is at 460 nm. These spectra have be used to determine the concentration of OLOA 1200 in solution for adsorption isotherms. 

The separation between the adsorption peak (pre- or post-peak) and the peak due to the diffusive electron transfer can be taken as a qualitative... 

It is noted that on increasing the scan rate the intensity of the adsorption peak (which linearly increases with v) tends to become larger than that of the diffusive peak (which linearly increases with v1/2), such that at high scan rates the diffusive peak may completely disappear. 

Before addition of the benzyl halide, the only carbonyl adsorption peak is found at 1900 cm, indicative of the cobalt tetracarbonyl anion. After addition, this band immediately disappears and peaks at 2000 cm l are observed. These most likely represent the corresponding acyl complex. Reaction with methoxide yields the product and regenerates the cobalt anion. In the absence of sufficient methoxide, the reaction requires attack by the much... 

Figure 4.36 shows the UV absorbance spectra of diethyl dixanthogen (EX)2, diethyl monothiocarbonate (MTC ) and diethyl thiocarbonate (EPX). The UV adsorption peaks of (EX)2 lie in about 238 nm (strong) and 286 nm (weak). The ratio of adsorption intensity of two peaks is 2. UV peak of MTC lies in about 225 nm (strong), EPX lies in about 348 nm (strong) and 221 nth (weak). 

An AMl/ZINDO-CI approach was used to predict the optical adsorption spectra for a series of polybenzobisox-azoles such as 5. The calculations indicated that the adsorption peaks should become blue-shifted as the torsion angle increases <2004PLM8871>. 

When using the continuous flow method, however, some additional versatility is available in chemisorption measurements. For example, when data is required at an adsorbate pressure of 0.1 atm, a 10 % mixture of adsorbate, mixed with an inert carrier gas, is passed through the apparatus with the sample cooled to a temperature at which no chemisorption can occur. Upon warming the sample to the required temperature, adsorption occurs producing an adsorbate-deficient peak that is calibrated by injecting carrier gas into the flow stream. Equation (15.9) is then used to calculate the quantity adsorbed. This process is repeated for each concentration required. Caution must be exercised to avoid physical adsorption when the sample is cooled to prevent chemisorption. Should this occur, the adsorption peak due to chemisorption can be obscured by the desorption peak of physically bound adsorbate when the sample is heated. 

Since tailing effects were often observed with adsorption peaks, they were not used in the calculation of surface area (Figure 11.1). A comparison of the specific surface area of several materials obtained by the classical BET method and the N/E method is given in Table 11.1... 

The current-potential behavior shown in Figure 5.22 is claimed to be characteristic of a clean platinum surface in a clean test solution,99 and can be used as a criterion of solution and electrode cleanliness in aqueous 0.5 M H2S04. The presence of organic material generally will cause a decrease in the hydrogen adsorption peaks and the appearance of new peaks. 

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