Water chlorinationWater chlorination is the process of adding chlorine or chlorine compounds such as sodium hypochlorite to water. This method is used to kill bacteria, viruses and other microbes in water. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, and typhoid. In a paper published in 1894, it was formally proposed to add chlorine to water to render it "germ-free". Two other authorities endorsed this proposal and published it in many other papers in 1895.
BromideA bromide ion is the negatively charged form (Br−) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retardant materials, and cell stains. Although uncommon, chronic toxicity from bromide can result in bromism, a syndrome with multiple neurological symptoms. Bromide toxicity can also cause a type of skin eruption, see potassium bromide. The bromide ion has an ionic radius of 196 pm.
Disinfection by-productDisinfection by-products (DBPs) are organic and inorganic compounds resulting from chemical reactions between organic and inorganic substances such as contaminates and chemical treatment disinfection agents, respectively, in water during water disinfection processes. Chlorinated disinfection agents such as chlorine and monochloramine are strong oxidizing agents introduced into water in order to destroy pathogenic microbes, to oxidize taste/odor-forming compounds, and to form a disinfectant residual so water can reach the consumer tap safe from microbial contamination.
ChlorineChlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.
Sodium hypochloriteSodium hypochlorite, commonly known in a dilute solution as (chlorine) bleach, is an inorganic chemical compound with the formula NaOCl (or NaClO), consisting of a sodium cation (Na+) and a hypochlorite anion (OCl-or ClO-). It may also be viewed as the sodium salt of hypochlorous acid. The anhydrous compound is unstable and may decompose explosively. It can be crystallized as a pentahydrate NaOCl·5H2O, a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated.
Water purificationWater purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for human consumption (drinking water), but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The history of water purification includes a wide variety of methods.
Potassium bromidePotassium bromide (KBr) is a salt, widely used as an anticonvulsant and a sedative in the late 19th and early 20th centuries, with over-the-counter use extending to 1975 in the US. Its action is due to the bromide ion (sodium bromide is equally effective). Potassium bromide is used as a veterinary drug, as an antiepileptic medication for dogs. Under standard conditions, potassium bromide is a white crystalline powder. It is freely soluble in water; it is not soluble in acetonitrile.
Chlorine dioxideChlorine dioxide is a chemical compound with the formula ClO2 that exists as yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is usually handled as an aqueous solution. It is commonly used as a bleach. More recent developments have extended its applications in food processing and as a disinfectant. The molecule ClO2 has an odd number of valence electrons, and therefore, it is a paramagnetic radical.
Chlorine-releasing compoundsChlorine-releasing compounds, also known as chlorine base compounds, is jargon to describe certain chlorine-containing substances that are used as disinfectants and bleaches. They include the following chemicals: sodium hypochlorite (active agent in bleach), chloramine, halazone, and sodium dichloroisocyanurate. They are widely used to disinfect water and medical equipment, and surface areas as well as bleaching materials such as cloth. The presence of organic matter can make them less effective as disinfectants.
BromomethaneBromomethane, commonly known as methyl bromide, is an organobromine compound with formula CH3Br. This colorless, odorless, nonflammable gas is produced both industrially and biologically. It has a tetrahedral shape and it is a recognized ozone-depleting chemical. It was used extensively as a pesticide until being phased out by most countries in the early 2000s. Bromomethane originates from both natural and human sources. In the ocean, marine organisms are estimated to produce 56,000 tonnes annually.
