Vapor disinfectants

Uses Organic synthesis disinfectant vapor sterilant. 

Room disinfection room air and surfaces can be disinfected by spraying or vaporizing of aldehydes, provided that germs are freely accessible. 

Uses. Vapor sterilant and disinfectant intermediate in the production of acrylic acid and... 

Chemical (vapor phase) Ethylene oxide Propylene oxide Formaldehyde (3 - Propiolactone Disinfection temperature Ethylene oxide also used as sterilizing agent Possible carcinogenic activity of p-propiolactone... 

For disinfection and oxidation purposes, UV-C radiation is normally used although the application of other types of UV radiation has also been reported in the literature [10]. For example, the use of UV-A or even visible radiation to treat natural organic matter present in surface water has been reported with and without the presence of catalysts [82,83]. Concerning the utilization of UV-C radiation, the most common use is 254-nm radiation due to the development of low-pressure vapor mercury lamps by Hewitt in 1901 [13]. For this reason, in this chapter the information presented mainly focuses on the use of 254-nm UV-C radiation. 

Exposures to solvents occur throughout life from conception to death. Solvent vapors inhaled by the mother often reach the fetus. The elderly often spend their last days in the hospital where the odor of the solvents, disinfectants often prevails. Exposures also occur in the course of daily living. Exposures may range from the inhalation of vapors from a newspaper freshly off the news stand, to the intake of the cleaning solvent by all routes of exposure being used. Effects from the exposure may range from simple objection to a low concentration odor, to death at high concentrations. In between, there is a whole spectrum of effects. 

Consider para-dichlorobenzene (DCB), which is used as a toilet disinfectant. The following data are available for DCB the molecular weight is 146 g/mol, the liquid vapor pressure is 1.3 Torr, and the saturated water solubility is 5.3 x 10-4 mol/L. In Lake Zurich, the measured concentration of DCB is lOng/L and the average wind speed is 2.3 m/s. What is this compound s flux into or out of Lake Zurich ... 

Most of the 300+ organic vapors that may be found in indoor pollution are derived from paints, paint strippers and other solvents, wood preservatives, aerosol sprays, cleansers and disinfectants, moth repellents, air fresheners, in addition to fuels and automotive products, and dry-cleaners. Many of these compounds are halogenated hydrocarbons, PAH, ketones and aldehydes, which exhibit different degrees of toxicity. 

Pesticides may be periodically inttoduced into indoor air by direct application (e.g. insect sprays and bombs, disinfectant sprays and room deodorizers). In addition, there are often sources that continually emit vapors into the living space (e.g. continuous evaporation of residues from crack and crevice treatments and emissions from pest-control strips or other devices). Whether used inside the home or office, or outside on the lawn or garden, pesticides accumulate on indoor surfaces, especially in carpet dust, and also in upholstery and in or on children s toys (Lewis et al 1994b, 1999 Simcox et al., 1995 Nishioka et al 1996, 1999 Gurunathan et al., 1998). 

Lamp bulbs are typically 0.75 m to 1.5 m in length and 15-20 mm in diameter. Mercury vapor is sealed inside this bulb. To produce the radiation, electric current, which generates an electric arc, is passed through the bulb. In actual use in the treatment of water and wastewater, the lamps are either suspended over the liquid to be disinfected or immersed in it. When immersed, the lamps are encased in quartz tube to prevent the cooling effect of the liquid on the lamps. The right-hand side portion of Figure 17.13 shows an ultraviolet lamp assembly the left-hand side shows an actual installation located below floor level. 

Free formaldehyde is used in cosmetics, especially in hair shampoos, and in many disinfectants and antiseptics. The solid paraformaldehyde is used as a source of formaldehyde vapor for the disinfection of rooms. Noxythiolin, polynoxyUn, hexamidine, and taurolidine act by slow release of formaldehyde. Formaldehyde solution contains 34—38% of formaldehyde methanol as a stabilizing agent to delay polymerization of the formaldehyde. Formaldehyde gel contains 0.75% of formaldehyde and is used to treat warts. 

Aldehydes such as glutaral, formaldehyde, and glyoxal are used as solutions and vapors for disinfection and sterilization. 

UV radiation has been used widely in water and air disinfection, as well as organic pollutant oxidation. The germicidal properties of UV radiation were first discovered in 1801. In 1877, the bactericidal effect of sun light (contaiiung UV fight with a wavelength more than 290 nm) was reported by Downes and Blunt. In 1901, the first mercury vapor lamp was commercialized as a method of UV generation (1). Nine years later, the... 

UV lamps are housed within the lamp sleeves. Quartz is often used to build lamp sleeves with open ends. The sleeve is used to protect, cool, and insulate the UV lamps. The most commonly used lamps in water and wastewater disinfection are low-pressure low-intensity mercury vapor lamps [also termed low-pressure low-output (LPLO) mercury vapor lamps], low-pressure high-intensity mercury vapor lamps (also termed as LPHO mercury vapor lamps), and medium-pressure mercury vapor lamps. Other lamps include electrode-less mercury vapor lamps, metal halide lamps, xenon lamps (pulsed UV), and eximer lamps. UV lamps may be oriented parallel, perpendicular, or diagonal to flow or ground. Orienting MP lamps horizontally relative to the ground prevents differential heating of the lamps and reduces the potential for lamp breakage. 

The water is treated with UV radiation for primary disinfection, then chlorinated for secondary disinfection. An applied chlorine dosage of only about 1 mg/L is necessary. The entire water treatment system is housed in a 2.97 m (32 fU) building. The UV disinfection system consists of six irradiation chambers, two control cabinets with alarms, chart recorders, relays, hour-run meters, lamp and power on-lights, six thermostats, electrical door interlocks, mimic diagrams, and six UV intensity monitors measuring the total UV output. Each irradiation chamber contains one 2.5-kW mercury vapor, medium-pressure arc tube, generating UV radiation at 253.7 nm. 

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