Small organic adsorbates, effect

It is necessary to install air filters in the rimning nuclear power plants with the special aim to adsorb effectively radioactive iodine vapors emitted upon malfunctions of the nuclear power plants. The normal or minor malfunction of nuclear power plants may result in the generation of considerable amounts of radioactive elemental and small amoimts of organic iodine vapor or dust. The iodine waste, due to being fission intermediates, is the primary target for effective entrapment and immobilization to prevent the spreading of nuclear contaminants. If iodine can be effectively immobilized, then the majority of radioactivity remains localized. 

EMIRS has been successfully applied to many systems. Briefly it can be mentioned the study of adsorbates at the electrode surface [10], the detection of adsorbed reaction intermediates for the oxidation of small organic molecules [12], and the determination of the water structure in the double layer [13]. However, the potential modulation in EMIRS is its drawback, since it prevents the study of irreversible processes as the system must return to the same conditions each time the potential is changed. Other important limitations of EMIRS are related to both the electrical and chemical relaxation effects caused by the potential modulation at 12 Hz. The electrical relaxation is due to the high ohmic drop of the electrolyte confined in the thin solution layer required for the in situ measurements. The chemical relaxation is due to ion migration induced by the change in solution composition caused by the electrode potential change. These aspects have been discussed in detail in the following text [14-16] (see Sect. 3.4.2.3). 

On the other hand, carbon-supported Pt catalysts for the electrooxidation of formic acid are severely poisoned by the adsorbed CO intermediate of the reaction [14—16], although platinum is at present the best-known catalyst for the dissociative adsorption of small organic molecules. It has been demonstrated [17, 18] that PtRu and PtPd alloys can diminish this CO poisoning effect to some extent. 

The AIREs have a higher surface selectivity and sensitivity thus, the interface/surface reactions can be selectively monitored with less interference from the bulk solution. Generally, in situ FTIRS studies are concerned with the dissociative adsorption and oxidation of organic molecules, the formation, adsorption and oxidation of intermediates, the nature of adsorbed species and their interaction with catalysts, the determination of reaction selectivity, and also effects of catalyst composition, size, and morphology. The dual-path mechanism and active/poisoning intermediates in the electrooxidation of small organic molecules (SOMs) have been well characterized by in situ FTIRS methods. ... 

As is well known (Morse and Berner, 1972) even very small concentrations of HPO (and some organic solutes) inhibit nucleation of CaC03, most likely because these adsorbates block essential surface sites on the substrate or on the mineral clusters. Mg2+ is known to inhibit many nucleation processes, especially also the nucleation of Mg bearing minerals. The water exchange rate of Mg2+ is slower than that of many cations, such as Pb2+, Cu2+, Zn2+, Cd2+, Ca2+. The inhibition effect of Mg2+ may be due to its sluggishness to (partial) dehydration. (Mg2+ has among the bivalent ions a very large enthalpy (-AHj,) of hydration.)... 

The Tenax-silica gel combination trap utilizes the adsorptive properties of two materials to provide a trap that effectively adsorbs and desorbs a wide variety of organic compounds. The small amount of OV-1 on glass wool at the trap inlet (Figure 2) is to insure that all the Tenax adsorbent is within the heated zone and is efficiently heated to the desorption temperature. A metal fitting at the trap inlet could act as a heat sink and create a cool spot on the Tenax if this spacer is not used. 

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