Base exchange

As an adjective applied to metals base represents the opposite of noble, i.e. a base metal would be attacked by mineral acids, base exchange An old term used to describe the capacity of soils, zeolites, clays, etc. to exchange their cations (Na, K, Ca ) for an equivalent of other cations without undergoing structural change. An example of the general process of ion exchange. ... 

Base exchange The property of the trading of cations shown by certain in- soluble namrally occurring materials (zeolites) and developed to a high degree of specificity and efficiency in synthetic resin adsorbents. 

Voids The space between the resinous particles in an ion-exchange bed. Zeolite Naturally occurring hydrous silicates exhibiting limited base exchange. 

Indian Ion Exchange and Chemical Industries - Produces reverse osmosis and demineralization systems, base exchange softeners, clarifiers and filters, degassers and de-aerators, filtration and micro filtration systems, effluent treatment plant...http //www.indianionexchange.com. ... 

The base exchange process removes both the temporary and permanent hardness salts from the water by allowing the water to flow through resin beads containing sodium zeolite, Na2Z. 

In reverse osmosis, the osmotic pressure is increased manually to get the water to flow from a high-density area through a semipermeable membrane to the lower-density weaker solution. The water will pass through the membrane and leave the solids behind. A pressure of about 2.76 MPa will extract 90% or more of the dissolved absorbed solids further refinement may be achieved through a base exchange process. 

Boiler water treatment Base exchange Dealkylization Demineralization Demin, water tank Demin, water pump Bulk acid and alkali storage Neutralizing... 

Where the feed contains a large proportion of treated water, softening is a minimum requirement and the raw water quality dictates whether a more sophisticated form of external treatment would be preferable. If the water has a high alkalinity it calls for de-alkalization and base exchange. De-ionization is the ideal water treatment, but is usually avoided if possible because of its cost and use of corrosive chemicals. Membrane processes giving partial de-ionization are not normally installed at present, but are certain to become important in the future. 

The operation of a base exchanger is chemically inefficient, and the spent regenerant contains large amounts of excess salt which may occasionally be difficult to dispose of. Factory softeners make a major contribution to the chloride content of the UK s industrial rivers, and in the longer term there will be heavy pressure from environmentalists to reduce the amount of salt being discharged. 

Hardness breakthrough with ion-exchange (base exchange, BX) softening NOTE Caused by Fe/Mn fouling, resin breakdown/loss, or inadequate regeneration. Increased risk of carbonate scale or phosphate sludge Loss of alkalinity and hence an increased silica deposition risk... 

Sodium cycle softening (base-exchange softening) is used primarily to remove the risk of calcium- and magnesium-based crystalline scale formation and deposition. The general reaction is as shown in Figure 9.2. 

Replacement of positive ions of a soluble salt by passing sodium through a cation resin (softening or base exchange) or hydrogen through an acidic resin (as in one half of the demineralization process). 

AVT Barg BD BDHR BF BOF BOOM BOP BS W BSI BTA Btu/lb BW BWR BX CA CANDUR CDI CFH CFR CHA CHF CHZ Cl CIP CMC CMC CMC COC All-Volatile treatment bar (pressure), gravity blowdown blowdown and heat recovery system blast furnace basic oxygen furnace boiler build, own, operate, maintain balance of plant basic sediment and water British Standards Institution benzotriazole British thermal unit(s) per pound boiler water boiling water reactor base-exchange water softener cellulose acetate Canadian deuterium reactor continuous deionization critical heat flux Code of Federal Regulations cyclohexylamine critical heat-flux carbohydrazide cast iron boiler clean-in-place carboxymethylcellulose (sodium) carboxy-methylcellulose critical miscelle concentration cycle of concentration... 

This is usually prepared by either a base-exchange method using sodium zeolite, by a lime-soda ash process, or by the addition of sodium hexametaphosphate. In addition to the bacteria derived from fhe mains water, additional flora of Bacillus spp. and Staphylococcus aureus may be introduced into systems which use brine for regeneration and from the chemical filter beds which, unless treated, can act as a reservoir for bacteria. 

In agreement with the resuhs obtained by other authors, CoM was active for SCR ofNO with CH (3,5). In 6ct, Co with 42% ofB.E.C. (Base Exchange Capacity) presented a maximumNOto Nj conversion of 31 % at 450°C (Fig. 1), the selectivity at this tenqrerature being 0.74. When the sample was reduced at 350° and 500°C a decrease ofNO conversion was observed (Table 2). 

All these methods have in common that the receptor is not detected so that no size limit applies. Relaxation-based exchange-transferred experiments actually show best performance for longest correlation times, i.e. very large receptors. 

If an amphiprotic solvent contains an acid and base that are neither mutually conjugate nor are conjugated with the solvent, a protolytic reaction occurs between these dissolved components. Four possible situations can arise. If both the acid and base are strong, then neutralization occurs between the lyonium ions and the lyate ions. If the acid is weak and the base strong, the acid reacts with the lyate ions produced by the strong base. The opposite case is analogous. A weak acid and a weak base exchange protons ... 

Increasing KC1 concentration lowers inhibition as shown in Table II. The fact that damage increased with KC1 concentration is consistant with the ionic ratio hypothesis and suggests a base exchange mechanism whereby calcium ions are more easily extracted from the clay and replaced by potassium ions as the potassium concentration increases. 

It is worth looking at the various base sequences with the help of the genetic code. All the pairs of codon units which are linked by arrows in Table 8.2 differ by only one single base exchange. 

Table 5.2 Equilibrium and rate constants for VO(acac)2-Base exchange.

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