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Available chlorine, definition

The total concentration or amount of chlorine-based oxidants is often expressed as available chorine or less frequendy as active chlorine. Available chlorine is the equivalent concentration or amount of Cl needed to make the oxidant according to equations 1—4. Active chlorine is the equivalent concentration or amount of Cl atoms that can accept two electrons. This is a convention, not a description of the reaction mechanism of the oxidant. Because Cl only accepts two electrons as does HOCl and monochloramines, it only has one active Cl atom according to the definition. Thus the active chlorine is always one-half of the available chlorine. The available chlorine is usually measured by iodomettic titration (7,8). The weight of available chlorine can also be calculated by equation 5. [Pg.142]

The % available chlorine from calcium hypochlorite by definition includes CI2, HCIO, and OCl (but not Cl ), is 99.2%, or nearly the same effectiveness on a weight for weight basis as treating with elemental chlorine [9]. As long as the residual chlorine level used with hypochlorite salt disinfections is the same as with chlorine gas, there is no difference in relative effectiveness. [Pg.143]

Depending on pH and products formed, the effective residual concentration of chlorine [free available chlorine (FAC)] HOCl or OCl is 0.1-0.2 mg/L. Higher concentrations tend to give water a definite taste. [Pg.266]

Rejection Rejection is defined in Background and Definitions. The highest-rejection membranes are those designed for single-pass production of potable water from the sea. The generally accepted criterion is 99.4 percent rejection of NaCl. Some membranes, notably cellulose triacetate fibers are rated even higher. A whole range of membranes is available as rejection requirements ease, and membranes with excellent chlorine resistance and hydrolytic stability can be made with salt rejection over 90 percent. [Pg.2036]

A limited number of pure substances are available from NIST, primarily clini-cally-relevant compounds such as cholesterol, urea, uric acid, creatinine, glucose, cortisol, tripalmitin, and bilirubin (NIST SRM website). These compounds are certified for purity (greater than 99 %) and are used as primary calibrants in definitive methods for these clinical analytes (see below). Several additional pure substances are available for specific applications such as microchemistry, i.e. elemental composition (acetanilide, anisic acid, cystine nicotinic acid, o-bromobenzoic acid, p-fluoro-benzoic acid, m-chlorobenzoic acid), polarimetric standards (sucrose and dextrose), acidimetric standard (benzoic acid and boric acid). Only three pure substance NIST RMs are available for environmental contaminants, namely the chlorinated pesticides, lindane, 4,4 -DDT, and 4,4 -DDE. [Pg.85]

Rubber Company Handbook (Weast, 1987) is one of the more commonly available sources. More complete sources, including some with data for a range of temperatures, are listed in the references at the end of the chapter. Note that many tabulations still represent these energy functions in calories and that it may be necessary to make the conversion to Joules (1 cal = 4.1840J). Because of the definition of the energy of formation, elements in their standard state (carbon as graphite, chlorine as CI2 gas at one bar, bromine as Br2 liquid, etc.) have free energies and enthalpies of formation equal to zero. If needed, the absolute entropies of substances (from which AS may be evaluated) are also available in standard sources. [Pg.74]

Application of this 1/100 safety factor to the NOAEL (1 ng/kg/day or 1000 pg/kg/day) defined in the lifetime rat study (30) that is considered most definitive by essentially all of the regulatory agencies was the basis for the Ontario MOE expert panel to recommend a Maximum Daily Intake for 2,3,7,8-TCDD (or its toxic equivalent of other chlorinated dioxins and furans) of 10 pg/kg B.W./day for humans (38). This more recent approach used by these four non-U.S. groups demonstrate the manner in which carcinogenicits based lifetime exposure control limit recommendations for humans can be realistically derived from the data available from the animal cancer bioassays when interpreted in concert with the data available regarding the likely mechanism of action by which the carcinogenic response occurred in the animal bioassays. [Pg.65]

Chlorine (CI2) is one of the more commonly produced chemicals in the United States, and chlorine gas is a potent oxidant that is very irritating and, potentially, corrosive (Wismer, 2007 Kikilo et al., 2008 Smith et al., 2008). Chlorine gas is used as a pulmonary and choking agent, and exposure is frequently associated with moderate to severe painful irritation of the eyes and respiratory tract (Wismer, 2007). Such stressful sublethal exposmes in late-gestational women or animals might be expected to be associated with the induction of premature parturition and, possibly, spontaneous abortion. Oxidative stress can definitely have adverse effects on reproductive function, but the chronic disease usually associated with chlorine gas exposme is primarily related to the ocular and respiratory systems (Smith et al., 2008). The limited information available regarding the reproductive effects of chlorine gas indicates that it is teratogenic (Wismer, 2007). [Pg.605]


See other pages where Available chlorine, definition is mentioned: [Pg.27]    [Pg.27]    [Pg.146]    [Pg.87]    [Pg.199]    [Pg.16]    [Pg.171]    [Pg.124]    [Pg.743]    [Pg.510]    [Pg.159]    [Pg.743]    [Pg.2858]    [Pg.5061]    [Pg.575]    [Pg.100]    [Pg.311]    [Pg.83]    [Pg.1659]    [Pg.423]    [Pg.623]    [Pg.278]    [Pg.394]    [Pg.203]    [Pg.592]    [Pg.524]    [Pg.36]    [Pg.116]   
See also in sourсe #XX -- [ Pg.7 ]




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