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Mechanism in water

Inorganic salts of metals work by two mechanisms in water clarification. The positive charge of the metals serves to neutralize the negative charges on the turbidity particles. The metal salts also form insoluble metal hydroxides which are gelatinous and tend to agglomerate the neutralized particles. The most common coagulation reactions are as follows ... [Pg.307]

In the aim of a better understanding of paramagnetic relaxation mechanisms in water-soluble gadofullerenes, variable... [Pg.116]

Tapia, O., Lluch, J. M., Cardenas, R. and Andres, J. Theoretical study of solvation effects in chemical reactions. A combined quantum chemical/Monte Carlo study ofthe Meyer-Schuster reaction mechanism in water, J. Am. Chem.Soc., Ill (1989), 829-835... [Pg.356]

This mechanism is supported by identical dissociation and racemization rate constants. This further implies either that the bis species M(AA)2 is racemic as formed, or that it may racemize (by a cis-trans change, or by a dissociative or intramolecular path) more rapidly than it re-forms iris in the dynamic equilibrium (7.23). Identical activation parameters for the dissociation (to the bis species) and racemization in aqueous acid (Table 7.5) and other solvents of Nifphen) " and Ni(bpy)3 indicate that these ions racemize by an intermolecular mechanism. This is the only such example for an M(phen)"+ or M(bpy) + species (see Table 7.5) although recently it has been observed that Fe(bps)3 (bps is the disulfonated phenanthroline ligand shown in 13, Chap. 1) but not Fe(phen)3+ also racemizes predominantly by a dissociative mechanism in water. For the other tr/s-phenanthroline complexes (and for Fe(bps)3 in MeOH rich, MeOH/HjO mixtures ) an intramolecular mechanism pertains since the racemization rate constant is larger than that for complete dissociation of one ligand, Table 7.5. [Pg.344]

Figure 3. Proton conduction mechanism in iiquid imida-zoie, as revealed by a Car—Parrinello molecular dynamics (CPMD) simulation.3 Note the similarities with the proton conduction mechanism in water (see Figure 1). Figure 3. Proton conduction mechanism in iiquid imida-zoie, as revealed by a Car—Parrinello molecular dynamics (CPMD) simulation.3 Note the similarities with the proton conduction mechanism in water (see Figure 1).
Figure 3. Scheme of ozone decomposition mechanism in water. P = promoter (e.g. ozone, methanol), S = scavenger or inhibitor (e.g. /-butanol, carbonate ion), I = initiator (e.g. hydroxyl ion, perhydroxyl ion) (adapted by Beltran [35]). [Pg.30]

Advocat, T., Jollivet, P., Crovisier, J. L. del Nero, M. 2001. Long-term alteration mechanisms in water for SON68 radioactive borosilicate glass. Journal of Nuclear Materials, 298, 55-62. [Pg.118]

A re-investigation of the mechanism of the hydrolysis of acetic anhydrides in water was made by Bunton and Fendler4. They found that the hydrolysis of trimethylacetic anhydride follows an A-2 mechanism both in water and in aqueous dioxan and is slower than that of acetic anhydride. If acetic anhydride follows an A-l mechanism in water, both anhydrides should have the same mechanism and both should have similar reactivities in aqueous acids. If the A-2 mechanism is followed, steric effects should make trimethylacetic anhydride the less reactive compound. The entropy of activation of the hydrolysis catalysed by perchloric acid was re-estimated, taking into account the electrolyte effect of the perchlorate ions upon the rate of spontaneous hydrolysis, and a new value for A5 of—35 eu (for the spontaneous hydrolysis) and — 10 eu at 2 M HC104 for the acid-catalysed hydrolysis was obtained, compared with the value of + 2.2eu obtained previously. The new value is in the order of magnitude of A 5 for A-2 reactions but smaller than that observed for trimethylacetic anhydride under similar acidic conditions (— 26 eu). Plots... [Pg.283]

The solubility of small molecules like rare gases or CH4- -C q in water decreases with TM 116 but increases with Tin cyclohexane. This indicates too that the solubility mechanism in water depends on a special ordered structure forming of water. Benzene and derivatives show a minimum of the T-dependence of the solubility in water. In homologous series the solubility in water decreases with increasing radius of the solute87 (Fig. 18) and becomes very low at a radius of more than 6 A. This... [Pg.142]

Cermenati L, Pichat P, Guillard C, Albini A. Probing the Ti02 photocatalytic mechanisms in water purification by use of quinoline, photo-Fenton generated OH radicals and superoxide dismutase. J Phys Chem B 1997 101 2650-2658. [Pg.121]

In addition to the more usual application to solids, dielectric relaxation or dispersion measurements are also used on solutions (and pure liquids). Cook (425) related the relaxation mechanism in water-dioxane mixtures to the rupture of H bonds. Hasted and co-workers (890) found that water-dioxane mixtures had longer relaxation times as the dioxane proportion increased or the temperature was lowered. Both trends are explained by formation of a H bonded complex. Yasumi (2219) found similar effects when large amounts of hexane... [Pg.30]

In this chapter we will first discuss briefly the basic theory behind ab nitio methods. Then a discussion of transition state theory, in light of the ab initio capabilities, will be taken up. This discussion will be followed by an analysis of the molecular mechanisms in water-silicate reactions and the ab initio elucidation of the adsorption and kinetic barriers involved in the bulk chemical reactions occurring at mineral-water interfaces. [Pg.260]

Figure 23.3 Proton conduction mechanism in water. The protonic defect follows the center of symmet of the hydrogen-bond pattern, which diffuses by hydrogen-bond breaking and forming processes. Therefore, the mechanism is frequently termed structure diffusion . Note that the hydrogen bonds in the region of protonic excess charge are... Figure 23.3 Proton conduction mechanism in water. The protonic defect follows the center of symmet of the hydrogen-bond pattern, which diffuses by hydrogen-bond breaking and forming processes. Therefore, the mechanism is frequently termed structure diffusion . Note that the hydrogen bonds in the region of protonic excess charge are...
The buffer mechanism in water can also be induced by some heterogeneous systems where exchange reactions between the ions in water and bottom sediments or minerals occur, or dissolution and precipitation of some minerals take place. [Pg.107]

Adsorption is the physico-chemical interaction between solutes and the membrane. The adsorption of organics, or more specifically humic substances, is considered a major fouling mechanism in water treatment. NOM can either adsorb in the structure of the cake and give the cake cohesion, or in the bulk of the membrane. These interactions are strongly influenced by membrane solute affinities and the... [Pg.65]

G3(MP2)-RAD level calculations in the gas phase, in water using the CPMP solvation model, and in water with LinA or LinB enzyme catalysis have been used to investigate the decomposition of three hexachlorocyclohexane isomers. Although the a- and y-hexachlorocyclohexanes react by an E2 mechanism in the gas phase, in water and with LinA enzyme catalysis, the /3-hexachlorocyclohexane reacts by an 5 2 mechanism in the gas phase and with LinB enzyme catalysis, but by an ElcB mechanism in water. The reaction rates for all three isomers are enzyme water Th results are consistent with experimental observations. [Pg.330]

Beslu, P. Observations on recent application of high coolant pH in French PWRs and optimization of chemistry during shutdown. Report IAEA TECDOC-667 Coolant Technology of Water Cooled Reactors. Vol. 3, Activity Transport Mechanisms in Water Cooled Reactors, Vienna 1992, p. 61—65... [Pg.334]

Thornton, E. W. Activity transport mechanisms in water cooled reactors. Report IAEA TECDOC-667 Coolant Technology of Water Cooled Reactors, Vol. 3 Activity Transport Mechanisms in Water Cooled Reactors., Vienna, 1992, p. 9—51 Walker, S. M., Thornton, E. W. Reanalysis of oxide solubility data. Proc. 5. BNES Conf Water Chemistry of Nuclear Reactor Systems, Bournemouth, UK, 1989, Vol. 1, p. 89—95 Walton, G. N., Hesford, E. The migration of activated corrosion products in high-pressure water loops. Proc. Conf Corrosion of Reactor Materials, Salzburg 1962, Vol. 2, p. 547-556... [Pg.338]

Diffusion in pore and crack in rocks and minerals is generally more important as micro scale mass transfer mechanism in water-rock system rather than diffusion in solid phases and in free water. [Pg.83]

Disequilibria studies have been used to understand particle d)mamics and the fate and transport of particle-reactive systems in marine environments and in low salinity and freshwater systems. Waples et al. [99] described a procedure to measure Th/ U disequilibria to understand natural mechanisms in water systems. The main advantage of their methodology is the use of small samples and low-background gas flow proportional counters. [Pg.91]


See other pages where Mechanism in water is mentioned: [Pg.973]    [Pg.316]    [Pg.413]    [Pg.591]    [Pg.276]    [Pg.255]    [Pg.7]    [Pg.242]    [Pg.249]    [Pg.62]    [Pg.454]    [Pg.721]    [Pg.79]    [Pg.31]    [Pg.125]    [Pg.509]    [Pg.143]    [Pg.840]    [Pg.62]    [Pg.311]    [Pg.173]   
See also in sourсe #XX -- [ Pg.252 , Pg.253 , Pg.254 , Pg.255 ]




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Water mechanisms

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