Multivalent ion

The flow can be radial, that is, in or out through a hole in the center of one of the plates [75] the relationship between E and f (Eq. V-46) is independent of geometry. As an example, a streaming potential of 8 mV was measured for 2-cm-radius mica disks (one with a 3-mm exit hole) under an applied pressure of 20 cm H2 on QT M KCl at 21°C [75]. The i potentials of mica measured from the streaming potential correspond well to those obtained from force balance measurements (see Section V-6 and Chapter VI) for some univalent electrolytes however, important discrepancies arise for some monovalent and all multivalent ions. The streaming potential results generally support a single-site dissociation model for mica with Oo, Uff, and at defined by the surface site equilibrium [76]. 

New factors for tlie establislmient of multilayer stmctures are, for example, tire replacement of tire hydrocarbon chain by a perfluorinated chain and tire use of a subphase containing multivalent ions [29]. The latter can become incoriDorated into an LB film during deposition. The amount depends on tire pH of tire subphase and tire individual ion. The replacement of tire hydrocarbon by a rodlike fluorocarbon chain is one way to increase van der Waals interaction and tlierefore enlrance order and stability in molecular assemblies [431. 

CMC/PAC sodium carboxy-methyl cellulose anionic 140 filtration control, viscosity builder sensitive to salinity, multivalent ions... 

Monovalent vs Multivalent Cation Selectivity 2.1 Multivalent Ion Exclusion... 

Though solid electrolytes for multivalent ions offer the advantage of a larger charge transfer, their conductivities are much lower than those of monovalent ions at ambient temperature because of a higher activation enthalpy for the ionic motion... 

The swelling behavior of hydrogels in solutions of multivalent ions capable to associate with the network-fixed charges, e.g., Cu2+, substantially differs from that described above, viz. the collapse of gels takes place [107]. As a result of this... 

The precipitation of polyelectrolytes by the addition of multivalent counterions may be explained in these terms. When there are no multivalent ions in solution there is a strong repulsive force between polyions and the osmotic pressure is large. The solubility of polyions is a result of these repulsive forces. 

Ion binding by reduction of repulsive forces also causes the attractive forces between polyions to increase, and the cement paste thickens. This interaction between polyions may be regarded as a kind of bridge formed by multivalent ions located between the polyions. At this stage the cement paste has the characteristic of a lyophilic sol - high viscosity. 

Physical crosslinking of carboxyl-functional polymers with multivalent ions... 

Besteman K, Zevenbergen MAG, Heering HA, Lemay SG. 2004. Direct observation of charge inversion by multivalent ions as a universal electrostatic phenomenon. Phys Rev Lett 93 170802/1-170802/4. 

Shklovskii BI. 1999. Screening of a macroion by multivalent ions Correlation-induced inversion of charge. Phys Rev E 60 5802-5811. 

Vourch et al49 studied the applicability of the RO process for the dairy industry wastewater. The treated wastewater total organic carbon (TOC) was <7 mg/L. It was found that in order to treat a flow of 100 m3/d, 540 m2 of the RO unit is required with 95% water recovery. Dead-end NF and RO were studied for the treatment of dairy wastewater.50 Permeate COD, monovalent ion rejection, and multivalent ion rejection for the dead-end NF were reported as 173-1095 mg/L, 50-84%, and 92.4-99.9%, respectively. When it comes to the dead-end RO membranes, the values for permeate COD, monovalent ion removal, and multivalent ion removal were 45-120 mg/L, >93.8%, and 99.6%, respectively. Membrane filtration technology can be better utilized as a tertiary treatment technology and the resultant effluent quality will be high. There can be situations where the treated effluents can be reused (especially if RO is used for the treatment). 

The behavior that we observed for the iodide ion is typical for the transfer of a univalent ion. For multivalent ions the situation is more complicated. Depending on the system under consideration and on the electrode potential a multivalent ion can either be transferred in one step, or its charge is first reduced by an electron-transfer reaction. Table 9.1 summarizes the different behavior of ion-transfer and electron-transfer reactions. 

The question of the importance of nonadditive corrections has been largely discussed and a growing body of results shows that many body effects can affect properties (specially for solutions of multivalent ions) in non-negligible ways [93- 104]. 

Equation (7) can be applied to interactions of multivalent ions of valence z dissolved in a dielectric by multiplying the right-hand side by (z2/Z>), where D is the dielectric constant of the medium. Equations (5) and (6) do not include ion-multipole and multipole-multipole interactions. A major part of these interactions may be represented by a pseudo dielectric constant which is relatively small and should not vary greatly from salt to salt in a given group.8... 

Based on these observations, in the composition of washing powders, multivalent phosphates are used, for instance, to keep the charged dirt particles from attaching to the fabrics after having been removed. Another example is wastewater treatment where, for coagulation purposes, multivalent ions are used. 

For multivalent ions, an equation representing the solute mobility must be derived that considers all the existing ionic species. For instance, the following equilibrium was established for an ampholyte, BH A ... 

Solarization is a photochemical reaction which leads to a change in color in glass. It is the result of long term exposure to the ultra violet radiation from sunlight. When certain multivalent ions or combinations of ions are present, their valence can be changed by the ionizing radiation. 

Generally, the reduction is achieved under deaerated conditions to avoid a competitive scavenging of Cjoiv and H atoms by oxygen. These atoms are as homogeneously distributed as the ions and the reducing species, and they are therefore produced at first as isolated entities. Similarly, multivalent ions are reduced by multistep reactions, including disproportionation of intermediate valencies. Such reduction reactions have been observed directly by pulse radiolysis for a variety of metal ions (Fig. 2), mostly in water [28], but also in other solvents where the ionic precursors are soluble. Most of their rate eonstants are known and the reactions are often diffusion controlled. 

Surfactant solutions used in cleaning processes are often alkaline. It is thus of some interest to study the dissolution of a mixture of a nonionic surfactant with an organic acid, which is converted to the corresponding soap in the alkaline solution. As soaps of multivalent ions such as calcium have low... 

It is known that double-layer effects are the most pronounced in the reaction of multivalent ions in a dilute solution. According to the calculation of Grahame, d°HP A3 potential region far from the pzc. Evaluate the cathodic and anodic Tafel slope values for the reaction... 

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