High pH waters

These data show that bromine works better than chlorine in high pH waters such as the ocean. Similarly, most industrial water is quite alkaline and therefore, a practical form of bromine is also preferred. The technical attributes of bromine antimicrobials are of value in water treatment and are apparently also worth the cost to many aquatic plants. Further observations of natural microbial fouling control systems reveal that animals also preferentially manufacture, in situ, certain bromine-based antimicrobials. 

However, if 10-min flotation treatments were used, oil recovery decreased drastically above a pH of 8. Further study revealed that low inter-facial tension develops in high pH water, given sufficient time. The 1-mm Strickland test did not allow enough time. 

Of all these products, sodium glucoheptonate has been the most widely used chelant in cooling water formulations. It shows a greater stability than sodium gluconate and retains the ability to chelate ions effectively in high pH water, which citrates and EDTA do not do so well. Sodium glucoheptonate is a sodium salt of polyhydroxymonocarboxylic acid (2,3,4,5,6,7-hexahydroxy-s-heptonic acid). It is a reaction product of sodium cyanide and sucrose. 

X 10 M at 25 °C). Lack of splitting of the H NMR signals of o- and m-phenyl protons of [TPPFeF2] supports the assumption of diaxial fluoride coordination with the metal in the plane of the porphyrin. In aqueous solution at high pH, water-soluble iron(III) porphyrins such as tetrakis(o-methylpyridinium)porphyrin, T(o-MPy)PFe , bind two hydroxide ions and give rise to a characteristic v no Fe H resonance Raman band at 447 cm ... 

The chosen reactants are then mixed together with a cation source, usually in a basic (high pH) water-based medium. 

Benzoates used on their own are not considered to be reliable corrosion inhibitors since, if insufiScient is added, corrosion is likely to remain ubiquitous. Benzoate has been used successfully to control corrosion of aluminium. The treatment however also included the simultaneous neutralisation of a high pH water, and it is possible, that the pH level could have been the controlling factor without which the benzoate may actually enhance corrosion [Neufeld etal 1987]. 

We have run experiments where only high pH water is supplied in the polishing machine and shown that without the presence of some colloidal silica, the removal rate goes to nil. This would imply that the aUcaU silicate salts from a somewhat protective skin over the siUcon surface. Likewise, the lower the pH, the lower the removal rate. One further proof that a chemical reaction is involved is the... 

Chem. Descrip 2-[(Hydroxymethyl)amino] ethanol CAS 34375-28-5 EINECS/ELINCS 251-974-0 Uses Presenrative for high pH water-based coatings Features May cause si. yellowing Prqterries Liq. 100% act. 

Chem. Descrip. 4,4-Dimethyloxazolidine CAS 51200-87-4 EINECS/ELINCS 257-048-2 Uses Preservative for high-pH water-based coatings, recirculating water systems... 

So Mono Lake is no garden spot, but neither is it dead. Local geology made the lakewater hard and basic, which shapes the local biology. Fish cannot survive in Mono Lake s high-pH water, but smaller, more nimble organisms can adapt and get everything they need. 

Carbon dioxide is used for pH adjustment. When added to water, it forms carbonic acid (a mild acid). It neutralizes high-pH water resulting from lime-soda softening (recarhonation) and adjusts alkalinity of naturally high-pH water. 

If either dry powders or inverse emulsions are not properly mixed with water, large lumps of polymer form that do not dissolve. This not only wastes material, but can also cause downstream problems. This is especially tme for paper where visible defects may be formed. Specialized equipment for dissolving both dry polymers and inverse emulsions on a continuous basis is available (22,23). Some care must be taken with regard to water quaUty when dissolving polyacrylamides. Anionic polymers can degrade rapidly in the presence of ferrous ion sometimes present in well water (24). Some cationic polymers can lose charge by hydrolysis at high pH (25). 

Metallic magnesium and water [7732-18-5] react. Under normal atmospheric conditions or in pure or chloride-free water of high pH, the reaction is suppressed by the formation of an insoluble magnesium hydroxide [1309-42-8] film. 

Some of the earlier BWR units had feedwater heaters having copper alloy tubes. The environment of high oxygen and neutral pH water led to high copper concentrations in the feedwater and to undesirable deposits on the fuel and inlet fuel nozzles (20). In some instances, the copper deposits resulted in an increase in core pressure drop and necessitated plant power reduction. The copper alloys were eliniinated from the feedwater system in subsequent plants and most existing plants. 

The second most common alkalinity control agent is lime [1305-78-8] normally in the form of calcium hydroxide [1303-62-0], used in both water and oH muds. In the latter, the lime reacts with added emulsifiers and fatty acids to stabHi2e water-in-oH emulsions. Lime is used in brine systems containing substantial quantities of soluble calcium and in high pH lime muds. Concentrations are ca 6—57 kg/m (2—20 lb /bbl) (see Lime AND LIMESTONE). 

The hydrolysis of phosphoms sulfides has been studied quantitatively. A number of products are formed (Table 6). Whereas phosphoms(V) sulfide reacts slowly with cold water, the reaction is more rapid upon heating, producing mainly hydrogen sulfide and orthophosphoric acid, H2PO4. At high pH, P4S Q hydroly2es to a mixture of products containing thiophosphates and sulfides. 

Commercial grades of socbum aluminate contain both waters of hycbation and excess socbum hycboxide. In solution, a high pH retards the reversion of socbum aluminate to insoluble aluminum hycboxide. The chemical identity of the soluble species in socbum aluminate solutions has been the focus of much work (1). Solutions of sodium aluminate appear to be totaby ionic. The aluminate ion is monovalent and the predominant species present is deterrnined by the Na20 concentration. The tetrahydroxyaluminate ion [14485-39-3], Al(OH) 4, exists in lower concentrations of caustic dehydration of Al(OH) 4, to the aluminate ion [20653-98-9], A10 2) is postulated at concentrations of Na20 above 25%. The formation of polymeric aluminate ions similar to the positively charged polymeric ions formed by hydrolysis of aluminum at low pH does not seem to occur. Al(OH) 4 has been identified as the predominant ion in dilute aluminate solutions (2). 

Neutral or alkaline salts, eg, KCl, K SO, K CO, or Na PO, are often present in synthetic latices in quantities of - <1%, based on the weight of the mbber. During emulsion polymerization the salts help control viscosity of the latex and, in the case of alkaline salts, the pH of the system. Many polymerizations are carried out at high pH, requiring the use of fixed alkaH, eg, KOH or NaOH. Very small amounts of ferrous salts can be employed as a component of the initiator system, in which case a sequesteriag agent, eg, ethyldiaminotetraacetic acid (EDTA) may be iacluded to complex the iron. Water-soluble shortstops, eg, potassium dithiocarbamate, may also be iacluded ia very small amounts (ca 0.1 parts). 

Hydrated amorphous silica dissolves more rapidly than does the anhydrous amorphous silica. The solubility in neutral dilute aqueous salt solutions is only slighdy less than in pure water. The presence of dissolved salts increases the rate of dissolution in neutral solution. Trace amounts of impurities, especially aluminum or iron (24,25), cause a decrease in solubility. Acid cleaning of impure silica to remove metal ions increases its solubility. The dissolution of amorphous silica is significantly accelerated by hydroxyl ion at high pH values and by hydrofluoric acid at low pH values (1). Dissolution follows first-order kinetic behavior and is dependent on the equilibria shown in equations 2 and 3. Below a pH value of 9, the solubility of amorphous silica is independent of pH. Above pH 9, the solubility of amorphous silica increases because of increased ionization of monosilicic acid. 

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