Anions multivalent

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

With respect to the carrier mechanism, the phenomenology of the carrier transport of ions is discussed in terms of the criteria and kinetic scheme for the carrier mechanism the molecular structure of the Valinomycin-potassium ion complex is considered in terms of the polar core wherein the ion resides and comparison is made to the Enniatin B complexation of ions it is seen again that anion vs cation selectivity is the result of chemical structure and conformation lipid proximity and polar component of the polar core are discussed relative to monovalent vs multivalent cation selectivity and the dramatic monovalent cation selectivity of Valinomycin is demonstrated to be the result of the conformational energetics of forming polar cores of sizes suitable for different sized monovalent cations. 

Similar to tannins, the polycarboxylic acid group provides a chelating function that ties up metal ions. The anionic sulfonate group functionality confers both solubility and dispersing capability for multivalent cations (calcium, iron, etc.). 

Comparison of the concentrations of either the cation or the anion in the two phases thus has potential for evaluating the polyanion valence provided that estimates of the mean ion activity coefficient (y ) are available. Furthermore, as realized by Svensson [165], expression of the Donnan distribution of small ions in this manner has two advantages in that (i) Eq. 31 applies to each type of small ion in situations where the supporting electrolyte is not restricted to single cationic and anionic species and (ii) multivalence of a small ion is also accommodated. 

Nanofiltration membranes are negatively charged and reject multivalent anions at a much higher level than monovalent anions, an effect described as Donnan exclusion. Nanofiltration membranes have MgS04 retention and water permeability claims. 

Friedl, W., Reijenga, J. C., and Kenndler, E., Ionic strength and charge number correction for mobilities of multivalent organic anions in capillary electrophoresis, /. Chromatogr. A, 709, 163, 1995. 

It has been known for some years that gramicidin forms transmembrane ion channels in lipid bilayers and biological membranes and that these channels are assembled from two molecules of the polypeptide 213). The channels are permeable specifically to small monovalent cations [such as H+, Na+, K+, Rb+, Cs+, Tl+, NH4+, CHjNHj, but not (CH3)2NH2+J and small neutral molecules (such as water, but not urea). They do not allow passage of anions or multivalent cations 21 n. 

The retarding effect of electrolytes in the application of basic dyes to acrylic fibres increases with increasing concentration of salt up to a certain level. Increasing the concentration beyond this point has no further effect on exhaustion with certain univalent anions, whilst with multivalent types there is an increase in dye sorption (Figure 12.2)... 

These results have led to the conclusion that ionic mechanisms alone do not entirely explain the complex interactions that occur between basic dyes and acrylic fibres. Hydrophobic interaction also plays an important part and it has been demonstrated [55] that multivalent anions such as sulphate or phosphate can enhance the hydrophobic interaction, thereby also increasing dye sorption in some circumstances. Whilst such results are of interest in terms of dyeing theory, it is extremely doubtful whether there will ever be practical interest in exploiting the use of electrolytes at such high concentrations. 

The hydration of polyoxyethylene (POE) is dramatically affected by the anion present(J 0) in the aqueous phase. The adsorption of HEC (both 2.0 and 4.3 M.S.) was therefore studied in Na SO and Na PO, at equivalent normalities. The multivalent anions are more effective in precipitating POE than is the chloride ion. The amounts adsorbed and the interlayer expansions at normalities below precipitation conditions are given in Table III. The influence of multivalent anions on the intrinsic viscosity of variable M.S. HECs is illustrated in Figure 6. The increased amounts adsorbed are within experimental error, but the decrease in d. with the 4.3 M.S. HEC is notable. The d. changes in the absence of increased adsorption are not explainable in terms of solvation effects. 

HYDROXYETHYL CELLULOSE ADSORPTION BEHAVIOR IN MULTIVALENT ANION SOLUTIONS... 

Kvaerner Chemetics have developed a novel, patented process [1] for the removal of multivalent anions from concentrated brine solutions. The prime market for this process is the removal of sodium sulphate from chlor-alkali and sodium chlorate brine systems. The sulphate ion in a brine solution can have a detrimental effect on ion-exchange membranes used in the production of chlorine and sodium hydroxide consequently tight limits are imposed on the concentration of sulphate ions in brine. As brine is continuously recycled from the electrolysers back to the saturation area, progressively more and more sulphate ions are dissolved and build up quickly in concentration to exceed the allowable process limits. A number of processes have been designed to remove sulphate ions from brine. Most of these methods are either high in capital or operating cost [2] or have large effluent flows. 

Washing and Cleaning Action. The properties of alkyl ether sulfates, due to the good solubility and the special hydrophilic/hydrophobic properties of the molecule, are of particular practical interest. From the investigations described in sections 2 and 3, it can be concluded that, in addition to the decrease in the Krafft Point, favorable properties for practical applications can be expected as a result of the inclusion of the oxyethylene groups into the hydrophobic part of the molecule. As is true for other anionic surfactants, the electrical double layer will be compressed by the addition of multivalent cations. By this means, the adsorption at the interface is increased, the surface activity is raised, and, furthermore, the critical micelle concentration decreased. In the case of the alkyl ether sulfates, however these effects can be obtained without encountering undesirable salting out effects. 

Additional information <1, 7-9, 12-17, 21> (<7> inhibitory effect of phosphonate analogues of 1,3-diphosphoglycerate, overview [49] <21> no effect by glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-phosphate, pyruvate, phosphoenolpyruvate and lactate [70] <13> double-inhibition studies, kinetics, modeling of inhibitor binding, e.g. phosphate [55] <13> enzyme is regulated by multivalent anions, overview [55] <8> no inhibition by Hg [25] <1,7,9,12-17> yeast enzyme is insensitive to thiol reagents [17]) [17, 25, 49, 55, 70]... 

Additional information <13, 21> (<21> no effect by glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-phosphate, pyruvate, phosphoenolpyru-vate and lactate [70] <13> enzyme is regulated by multivalent anions, overview [55]) [55, 70]... 

The substances to which the rules apply are those in which the bonds are largely ionic in character rather than largely covalent, and in which all or most of the cations are small (with radius less than 0.8 A) and multivalent, the anions being large (greater than 1.35 A in radius) and univalent or bivalent. The anions that are most important are those of oxygen and fluorine. 

As already pointed out in the preceding section, diffusion may be treated in terms of either of the functions P(a) or D(C). The former function is much simpler and has been used in the case of glassy polymer-gas systems for this reason, as we have seen. Its application to the present systems is more recent83,84). Eqs. (13) and (14) or Eqs. (13 a) and (14a) are directly applicable to monovalent dye anions. The same equations may be applied to multivalent dye ions following the (empirical) treatment of Eq. (22), provided that Sq in Eqs. (13) or (14) is replaced by Sq/z. Fig. 9 shows that... 

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