L- chlorine

There has been considerable research on chlorine-resistant RO membranes (48—52). A poly(/n j -2,5 dimethyl)pipera2inthiofura2anainide used in the presence of low (3 mg/L) concentrations of chlorine resulted in a membrane life of three years (48). A copolyamide hoUow-fiber membrane for use in desalination has been developed that is resistant to 0.5 mg/L chlorine (49). Millipore Corporation has also developed a sulfonated polysulfone member that has desirable chlorine-resistance properties. 

Picer and Picer [357] investigated the recovery from fO litre samples of seawater of 0.1-1.0 xg/l chlorinated pesticides (DDT, DDE, TDE, and Dieldrin), and 1-2 xg/l PCB (Aroclor 1254). The recovery of Mirex during these steps varied between 80% and 90%. Losses of the investigated chlorinated hydrocarbons during these steps were 10-30% for about 10 ng pesticides. 

Use of the resins with samples containing free chlorine residual is not recommended. Cheh (35) suggested that chlorine may produce mutagenic artifacts on XAD-4. Our experiment with 2-mg/L chlorine residual appeared to promote the release of irreversibly adsorbed spiked standards Six model compounds were recovered at levels several times higher than those observed in normal blank runs. In addition, many resin artifacts were eluted after exposure to this chlorine level, primarily aromatic and aliphatic acids, aldehydes, and ketones. Stoichiometric dechlorination (ferrous ion) is therefore recommended in order to avoid cross contamination between samples and inclusion of undesirable resin artifacts in the residue to be bioassayed. 

Some elements—particularly the halogens—form more than two kinds of oxoanions. The name of the oxoanion with the smallest number of oxygen atoms is formed by adding the prefix hypo- to the -ite form of the name, as in the hypochlorite ion, CIO. The oxoanion with more oxygen atoms than the -ate oxoanion is named with the prefix per- added to the -ate form of the name. An example is the perchlorate ion, C104. As can be seen from Table D.l, chlorine forms oxoanions that span the range. The same is true for bromine. The rules for naming polyatomic ions are summarized in Appendix 3A. 

Chlorine Azide or Chloroazide A529 L Chlorine Azidodithiocarbonate A635-R... 

Chlorine was first used to disinfect water in Britain in 1904, after a typhoid epidemic. (Typhoid is a water-borne, contagious illness that is caused by a species of Salmonella bacteria.) Strict limits are necessary because chlorine is ineffective when its concentration is less than 0.1 mg/L. It gives water an unpleasant taste at concentrations above 1.0 mg/L. Chlorine has a disadvantage, however. It can react with other chemicals in the water to form poisonous compounds, such as chloroform, CHCI3. These chemicals may remain in solution even after the entire treatment process. 

G24. Grisham, M. B., Jefferson, M. M., Melton, D. F., and Thomas, E. L., Chlorination of endogenous amines by isolated neutrophils. Ammonia-dependent bactericidal, cytotoxic, and cytolytic activities of the chloramines. J. Biol. Chem, 259, 10404-10413 (1984). 

After the water treatment is finished a safety chlorination is cai ried out to prevent reinfection of the potable water in the distribution network. This is also necessary after prior ozonization. Potable water contains about 0.1 to 0.2 mg/L chlorine. 

Examine the daily disinfection log sheet for chlorine feed rates and chlorine residual patterns. Compare both contact time and chlorine residual with those required by the proper regulatory agency. As a general rule, residuals between 0.2 and 1.0 mg/L after 15-30 min contact times provide good disinfection. As shown in the example, the 27 min contact time and 1.0 mg/L chlorine residual should be generally sufficient. 

A good municipal raw water supply with a total organic carbon (TOC) content of 2.4 mg/L and bromide ion concentration of 20 JLg/L is disinfected with 1.5 mg/L chlorine. 

Poutsma, M. L., Chlorination Studies of Unsaturated Materials in Nonpolar Media. 3. Competition between Ionic and Free radical Reactions During Chlorination of Isomeric Butenes and Allyl Chloride, J. Am. Chem. Soc. 1965, 87, 2172 2183. 

TREATABILITY/REMOVABILITY Process, Removable Range (%), Avg. Achievable Cone. ( xg/L)) Gravity oil separation, not available, 15.5 Filtration, 0, negative removal Sedimentation, >70-98, <5.3 Sedimentation with chemical addition (lime, polymer)-, 0, negative removal Sedimentation with chemical addition (lime)-, 0, negative removal Aerated lagoons, 33, 2 Powdered activated carbon adsorption (based on synthetic wastewater) 98, 0.03 Ozonation-, >90, <0.02 chlorination, 6 mg/L chlorine for 6 hr, initial concentration 53.14 ppb 98% reduction may be removed by reaction with O3 (half-life 37 min), and NO2 (half-life 7 days)... 

TREATABILITY/REMOVABILITY Process, Removable Range (%), Avg. Achievable Cone. (pg/L)) Sedimentation, 83, 6 Aerated lagoons, 0.4, 97 Powdered activated carbon adsorption (based on synthetic wastewater), 68, 0.040 Ozonation, >80, <0.02 Chlorination 6 mg/L chlorine for 6 hr initial concentration 5.18 ppb 34% reduction... 

Ko, J. H. and Odegaard, L., Chlorine Free Blends for Flexible Medical Tubing, Med. Plast. 

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