Dl Current Density Variation

The equations for the non-linear change in current density along the length of an ED cell with continuous and constant water flow were developed in Chapter 4. However, another, somewhat more detailed derivation is present below. For a better estimation of cell performance, we will treat the variation of current density along the flow path in closer approximation of reality. In Figure D.l the area current density is shown as the current conducted through an area of unit width and length, dx....

Electrolytic Conductivity

Bulk electrical properties of materials are conventionally defined as follows. The specific conductivity and resistivity of substances have the dimensional characteristics < 7 specific conductivity, mho-cm , or mho-in , and p - specific resistivity, ohm-cm (41) and, in the case of electrolytes, it is important to know the amount of electrically conducting components solutes present per unit volume of solution or liquid. This term is identified here as c concentration by weight of solutes, ppm...

Advantages of Electrodialysis

The method uses an entirely electrical process (electrochemical) that requires only a source of a.c. or d.c. power to operate. Some of the attendant advantages are outlined below. No mechanically moving parts Operates at standard temperature and pressure Low power consumption, efficient Self regulating, needs no on-off switching Made entirely of plastic - no corrosion or maintenance No vibration, sturdy and abuse resistant Not affected by impurities usually found in water Operates over wide...

F2 Capital Cost Analysis

Capital costs were developed from the major equipment lists and preliminary capital cost estimating techniques and factors. Installation labor costs were estimated based upon purchased equipment costs. Installed instrumentation and control costs were based upon equipment and process type 30 of the purchased equipment costs for the chlorination system and 20 of the purchased equipment costs for the bromination system. This cost difference is required when the safety precautions necessary in the...

Ion Exchange Resin Regeneration System 341 General

Of the various processes employed in water treatment, e.g. reverse osmosis, dialysis, ion-exchange, direct chemical treatment, filtration, etc., the ion-exchange process offers the highest purity water in terms of de-ionized content, especially the mixed bed version. Cation and anion exchange resins such as those produced by Rhom & Haas, Diamond Shamrock, and Dow are employed to remove the respective ions from solution. In a de-ionization apparatus there are either two separate beds of...

Free Energy and Equilibrium

The free energy change, AF in any process may also be represented as The equilibrium constant, K, for a process described between two reagents and two reactants The terms a , and b , etc. are concentrations of the respective components, or the expression employing activities may be used.

And RhG RohG

With these new generation terms equations (E.7) and (E.8) become, As before, we may now proceed to find the needed ninth and tenth equations. The first eight equations are (E.l) through (E.6) and (E.7a) and (E.9). Differentiation of equation (E.3) gives Equation (E.22) says dq J dt dqOH dt _ dq A dt and G irC + isL - ib A - icG + QA from the derivative of equation (E.5), we have by substitution into equation (E.22), irC (irC + isL - ibA - icG +QA) -isL - QA The tenth equation may be extracted...

Electrodialysis

Electrodialysis as a water processing mechanism has applications ranging from separation of ionic species in industrial processes to the production of potable water from sea water and demineralizing water sources. The principles of operation are quite simple and straightforward to comprehend, apply and manipulate for the purposes of achieving certain application criteria. In essence, a dialysis cell consists of four basic components two electrodes and two membranes. Electrodes are, of course,...

Bromination Process Description

It has been reported that bromine disinfection efficiency is lower than that achieved with chlorination. When tested under standard methods of disinfection evaluation, bromine, at 1.0 ppm was as effective as 0.6 ppm of available chlorine to control the bacteria (see E. Coli). This can be attributed to the higher oxidation potential of chlorine. However, one must be careful in its correlating ppm between chlorine and bromine by weight because the molecular weight of bromine is twice that of...