Hardness ion

Sequestration forms the basis for detergent and water-treatment appHcations of polyphosphates. Sequestration of hardness ions by sodium tripolyphosphate used in detergent formulations prevents the precipitation of surfactants by the hardness ions. Sodium polyphosphate glass (SHMP) may be added to water system to prevent the formation of calcium or magnesium scales by reducing the activity of the hardness ions. However, if the ratio of cation to polyphosphate is too high at a given pH, insoluble precipitates such as may result instead of the soluble polyphosphate complexes. The... 

A Acylsarcosinates. Sodium A/-lautoylsarcosinate [7631-98-3] is a good soap-like surfactant. Table 4 gives trade names and properties. The amido group in the hydrophobe chain lessens the interaction with hardness ions. A/-Acylosarcosinates have been used in dentifrices (qv) where they ate claimed to inactivate enzymes that convert glucose to lactic acid in the mouth (57). They ate prepared from a fatty acid chloride and satcosine ... 

Ethoxylated andSulfatedAlkylphenols. Because these aLkylphenols degrade less readily than the sulfated alcohol ethoxylates, their anticipated expansion failed to materialize, although by 1965 they were widely used in retail detergent products. Sulfated alkylphenol ethoxylates are used in hospital cleaning products, textile processing, and emulsion polymerization. Sulfated alkyphenol ethoxylates are sold as colorless, odorless aqueous solutions at concentrations of >30%. The presence of ethylene oxide in the molecule increases resistance to hardness ions and reduces skin irritation. Representative commercial sulfated alkylphenol ethoxylates are given in Table 12. 

The regeneration of the resin bed is never complete. Some traces of calcium and magnesium remain in the bed and are present in the lower-bed level. In the service run, sodium ions exchanged from the top layers of the bed form a very dilute regenerant solution which passes through the resin bed to the lower portion of the bed. This solution tends to leach some of the hardness ions not removed by previous regeneration. 

These hardness ions appear in the effluent water as leakage. 

Hardness leakage is also dependent on the raw water characteristics. If the Na/Ca ratio and calcium hardness are very high in the raw water, leakage of the hardness ions will be higher. 

Also, basic factors such as the transport of materials, residual hardness, ion leakage, soluble iron, colloidal silica and clays, and other contaminants, which can produce scales and deposits in the FW lines and other parts of the pre-boiler section, may also produce similar detrimental effects in the boiler section. In the boiler itself, however, the buildup rate may be quicker and the results may be more devastating. 

The design is further claimed to fully treat full flows of water in a single pass when installed direct to mains supplies, and water treated magnetically maintains its state for up to five days. Treatment results in hardness ions being attracted to other ions (rather than to pipework), resulting in a larger neutral body that has no ability to adhere to pipe walls or other contact surfaces, so that no incrustations or hard scales form. ... 

This chapter deals with sodium a-olefinsulfonate (AOS) and with sodium internal olefmsulfonate (IOS). AOS is a well-established product and is being applied in many household and industrial formulations. IOS of a sufficiently high quality has only recently been made on laboratory scale and pilot plant scale and has not yet been applied in commercial formulations. AOS and IOS have not only good wetting and detergency properties, but also good tolerance toward water hardness ions, a combination not always observed for other anionic surfactants. 

In spite of the good calcium and magnesium tolerance of AOS systems, situations can arise whereby too many exchangeable hardness ions present themselves to the surfactant formulation. One way to overcome this is by blending AOS with a divalent cation-tolerant surfactant. A product which has been field-tested [87] is a blend of AOS and a disulfonated alkyldiphenyloxide (DPOS). Calcium and magnesium salts of DPOS are water-soluble and remain soluble even in solutions which are very concentrated in calcium and magnesium salts. 

We can exploit the new results for packing contributions to reconsider the outer shell contribution in Eq. (33). For ionic solutes, the outer shell term would represent the Born contribution because it describes a hard ion stripped of any inner shell ligands. A Born model based on a picture of a dielectric continuum solvent is reasonable (see Section III,B, and Fig. 9, color insert). With that motivation, we first separate the outer shell term into an initial packing contribution and an approximate electrostatic contribution as... 

If tight ion pairs (between two hard ions) are involved in the reaction the microwave-accelerating effect then becomes more important, because of enhancement of ionic dissociation during the course of the reaction as tight ion pairs (GS) are transformed into more polar loose ion pairs (TS). 

In the first of these reactions, I is softer than F and As is softer than P. Therefore, the exchange takes place to provide a more suitable match of hard-soft properties. In the second reaction, Mg2+ is a small, hard ion, whereas Ba2+ is much larger and softer. The O2- ion bonds better to Mg2+, whereas S2-bonds better with Ba2+. The hard-soft interaction principle predicts correctly the direction of many reactions of diverse types. 

Calcium binding capacity Builder s hard ions complexation constant, K Increases with increasing K... 

Smaller, hard cations, such as alkyltrimethylammonium salts and crown ether-cation complexes, will promote the elimination of dichlorocarbene to form a hard ion pair of type Q+C1 . 

Another difficulty exists. It has been found that in the gas phase or in dipolar aprotic solutions, small anions (cations) have higher HOMO s (lower LUMO s) than the larger one. It follows that interaction between two hard ions is then favoured by both charge control and frontier control. Therefore, the equivalences suggested by Klopman ... 

Pt(II)and Pt(IV) are both soft cations, showing low affinities for hard ions and atoms (F, O) and high affinities for softer ions and atoms (Cl, Br, I, S, N) and for ligands that can pi bond. Practically all compounds of Pt can be reduced to Pt metal by ignition or moderately strong reducing agents. 

The resulting structure must be one that is chemically plausible. For example, coordination polyhedra that share faces usually bring the cations too close together, and arrangements that are connected in only one or two dimensions need to be carefully examined since the columns or layers will be held together only by Van der Waals bonds. Such bonding can be found between softer ions such as Cl or Br but is generally rare between hard ions such as F or 0 . 

Recent work suggests that B may be significantly larger than 37 pm for bonds between soft and hard ions (Adams 2001). 

The most common method to treat hard water is through a process called ion-exchange water softening, in which the hardness ions, magnesium and caicium, are exchanged with either sodium or occasionally potassium ions. 

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