scispace - formally typeset


About: Chlorine is a(n) research topic. Over the lifetime, 20879 publication(s) have been published within this topic receiving 254775 citation(s). The topic is also known as: Cl & element 17. more

More filters

Journal ArticleDOI
01 Jan 2008-Water Research
TL;DR: Comparison of chlorine to ozone reactivity towards aromatic compounds (electrophilic attack) shows a good correlation, with chlorine rate constants being about four orders of magnitude smaller than those for ozone. more

Abstract: Numerous inorganic and organic micropollutants can undergo reactions with chlorine. However, for certain compounds, the expected chlorine reactivity is low and only small modifications in the parent compound's structure are expected under typical water treatment conditions. To better understand/predict chlorine reactions with micropollutants, the kinetic and mechanistic information on chlorine reactivity available in literature was critically reviewed. For most micropollutants, HOCl is the major reactive chlorine species during chlorination processes. In the case of inorganic compounds, a fast reaction of ammonia, halides (Br(-) and I(-)), SO(3)(2-), CN(-), NO(2)(-), As(III) and Fe(II) with HOCl is reported (10(3)-10(9)M(-1)s(-1)) whereas low chlorine reaction rates with Mn(II) were shown in homogeneous systems. Chlorine reactivity usually results from an initial electrophilic attack of HOCl on inorganic compounds. In the case of organic compounds, second-order rate constants for chlorination vary over 10 orders of magnitude (i.e. <0.1-10(9)M(-1)s(-1)). Oxidation, addition and electrophilic substitution reactions with organic compounds are possible pathways. However, from a kinetic point of view, usually only electrophilic attack is significant. Chlorine reactivity limited to particular sites (mainly amines, reduced sulfur moieties or activated aromatic systems) is commonly observed during chlorination processes and small modifications in the parent compound's structure are expected for the primary attack. Linear structure-activity relationships can be used to make predictions/estimates of the reactivity of functional groups based on structural analogy. Furthermore, comparison of chlorine to ozone reactivity towards aromatic compounds (electrophilic attack) shows a good correlation, with chlorine rate constants being about four orders of magnitude smaller than those for ozone. more

1,280 citations

Journal ArticleDOI
Urs von Gunten1Institutions (1)
01 Apr 2003-Water Research
Abstract: Ozone is an excellent disinfectant and can even be used to inactivate microorganisms such as protozoa which are very resistant to conventional disinfectants. Proper rate constants for the inactivation of microorganisms are only available for six species (E. coli, Bacillus subtilis spores, Rotavirus, Giardia lamblia cysts, Giardia muris cysts, Cryptosporidium parvum oocysts). The apparent activation energy for the inactivation of bacteria is in the same order as most chemical reactions (35–50 kJ mol � 1 ), whereas it is much higher for the inactivation of protozoa (80 kJ mol � 1 ). This requires significantly higher ozone exposures at low temperatures to get a similar inactivation for protozoa. Even for the inactivation of resistant microorganisms, OH radicals only play a minor role. Numerous organic and inorganic ozonation disinfection/oxidation by-products have been identified. The by-product of main concern is bromate, which is formed in bromide-containingwaters. A low drinkingwater standard of 10 m gl � 1 has been set for bromate. Therefore, disinfection and oxidation processes have to be evaluated to fulfil these criteria. In certain cases, when bromide concentrations are above about 50m gl � 1 , it may be necessary to use control measures to lower bromate formation (loweringof pH, ammonia addition). Iodate is the main by-product formed duringozonation of iodidecontainingwaters. The reactions involved are direct ozone oxidations. Iodate is considered non-problematic because it is transformed back to iodide endogenically. Chloride cannot be oxidized during ozonation processes under drinking water conditions. Chlorate is only formed if a preoxidation by chlorine and/or chlorine dioxide has occured. r 2002 Elsevier Science Ltd. All rights reserved. more

1,023 citations

15 Aug 1992-
Abstract: Chlorine: History, Manufacture, Properties, Hazards, and Uses Hypochlorination On-Site Generation of Chlorine Chemistry of Chlorination Determination of Chlorine Residuals in Water and Wastewater Treatment Chlorination of Potable Water Chlorination of Wastewater Disinfection of Wastewater Chlorine Facilities Design Dechlorination Operation and Maintenance of Chlorination and Dechlorination Equipment Chlorine Dioxide Ozone Ozone, Peroxone, and AO x Ps Ozone Facility Design Bromine, Bromine Chloride, and Iodine Ultraviolet Radiation and AO x Ps Appendices Index. more

759 citations

Journal ArticleDOI
01 May 1957-Plant and Soil
Abstract: Recognition of chlorine as a plant micronutrient has been extended to include ten species. Acute chlorine deficiencies or decreased yields were produced with lettuce, tomato, cabbage, carrot, sugar beet, barley, alfalfa, buckwheat, corn, and beans. Squash plants showed neither loss in yield nor other deficiency symptoms when cultured at the same time and under the same conditions as the aforementioned species. All plants acquired more chlorine during their growth than can be accounted for from seeds, inorganic salts, or water used in the experiments. Plant species least susceptible to injury when cultured upon low chlorine salt solutions were also the ones most capable of acquiring extrinsic chlorine. Of the species studied, lettuce was the most sensitive to “minus chlorine” culture solutions and squash, the least sensitive. However, the concentration of chlorine in all of the species cultured under limited chlorine supply was not greatly different. It is inferred that plants such as corn, beans, and squash survived the “minus chlorine” cultures by reason of greater accretion of extrinsic chlorine from the atmosphere. The form of the atmospherically borne chlorine is not known. more

746 citations

Network Information
Related Topics (5)

5K papers, 70K citations

88% related

16.2K papers, 271.9K citations

88% related

39.9K papers, 759.2K citations

88% related

20.7K papers, 495.8K citations

87% related
Oxidizing agent

30.8K papers, 296.4K citations

87% related
No. of papers in the topic in previous years

Top Attributes

Show by:

Topic's top 5 most impactful authors

Chii Shang

31 papers, 1.8K citations

Gilbert Gordon

16 papers, 336 citations

Barbara J. Finlayson-Pitts

13 papers, 2.1K citations

Sukeo Onodera

13 papers, 181 citations

Leslaw Mleczko

13 papers, 52 citations