Chlorine

BackgroundThe environment preferred by Acanthamoeba trophozoites and the mechanism by which the amebae enters the cornea are not yet fully understood. A better understanding of the pathogenesis of this disease may help with prevention and treatment.

In this work, the vibrational spectral analysis was carried out using Raman and infrared spectroscopy in the range 100-4000 cm(-1) and 50-4000 cm(-1), respectively, for the title molecules. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartee Fock (HF) and density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The effects due to the substitutions of methyl group and halogen bond were investigated. The results of the calculations were applied to simulated spectra of the title compounds, which show excellent agreement with observed spectra.

Chlorine (Cl(2)) is a reactive oxidant gas used extensively in industrial processes. Exposure of both humans and animals to high concentrations of Cl(2) results in acute lung injury, which may resolve spontaneously or progress to acute respiratory failure. Injury to airway and alveolar epithelium may result from chemical reactions of Cl(2), from HOCl (the hydrolysis product of Cl(2)), and/or from the various reaction products, such as chloramines, that are formed from the reactions of these chlorinating species with biological molecules. Subsequent reactions may initiate self-propagating reactions and induce the production of inflammatory mediators compounding injury to pulmonary surfactant, ion channels, and components of lung epithelial and airway cells. Low-molecular-weight antioxidants, such as ascorbate, glutathione, and urate, present in the lung epithelial lining fluid and tissue, remove Cl(2) and HOCl and thus decrease injury to critical target biological targets. However, l...

ABSTRACT We report scapolite in a melt inclusion in olivine in Nakhla, which is the first occurrence of Cl-scapolite found in a martian meteorite. Using terrestrial metamorphic experiments and modeling we constrain its origin. Cl-rich scapolite in Nakhla is consistent with formation from either a late stage Cl-rich, water-poor magma or magmatic Cl-rich hydrothermal brine at a minimum temperature of 700 °C. The temperature of hydrothermal activity recorded by the Cl-scapolite is significantly higher than the temperatures recorded by alteration minerals in Nakhla, and the fluid was Cl-rich, not CO2-rich. Our results demonstrate that high-temperature Cl-rich fluids were present within the martian crust, and any potential biologic activity would have to survive in these high temperatures and saline fluids. Halophiles can thrive in NaCl-rich systems but at significantly lower temperatures than those recorded by the scapolite. During cooling of the fluid, the system could have reached a habitable state for halophiles. Importantly, halophiles can survive the conditions of space if they are encased in salt crystals, and therefore chlorine-rich phases present an opportunity to investigate for extant life both on the surface of Mars and in martian meteorites.

PCDD/F homologue profiles and 2,3,7,8 chlorine-substituted congener patterns are studied using principal component analysis and hierarchical cluster analysis. Measurement data from different industrial metallurgical processes such as iron and steel manufacturing, copper smelters and aluminium plants are compared. It appears that the PCDD/F homologue profiles from industrial metallurgical processes are similar to those from municipal solid waste incinerators. The 2,3,7,8 chlorine-substituted congener pattern from copper smelters is also very similar to that of municipal solid waste incinerators. However, the 2,3,7,8 chlorine-substituted congener pattern from an aluminum plant is very different, 2,3,7,8-TCDF being by far the most important TCDF congener.

Water Safety Plans (WSPs), recommended by the World Health Organization since 2004, seek to proactively identify potential risks to drinking water supplies and implement preventive barriers that improve safety. To evaluate the outcomes of WSP application in large drinking water systems in France and Spain, we undertook analysis of water quality and compliance indicators between 2003 and 2015, in conjunction with an observational retrospective cohort study of acute gastroenteritis incidence, before and after WSPs were implemented at five locations. Measured water quality indicators included bacteria (E. coli, fecal streptococci, total coliform, heterotrophic plate count), disinfectants (residual free and total chlorine), disinfection by-products (trihalomethanes, bromate), aluminum, pH, turbidity, and total organic carbon, comprising about 240K manual samples and 1.2M automated sensor readings. We used multiple, Poisson, or Tobit regression models to evaluate water quality before and...

Синёв А.В., Девяшин Т.В., Кунакова А.М., Сайфутдинова Л.Р., Усманова Ф.Г., Крикун А.Н., Лестев А.Е. Образование легколетучих хлорорганических соединений при первичной перегонке нефти в результате разложения химических реагентов, содержащих соли четвертичных аммониевых соединений // PROнефть. Профессионально о нефти. № 4(14). 2019. С. 63-68. DOI: 10.24887/2587-7399-2019-4-63-69

Users and providers of recycled water in Queensland, Australia, were canvassed to ascertain concerns about recycled water quality and directions for applied research. Some 79% of respondents had concerns about recycled water quality including microbiological components, such as viruses, parasites and bacteria, salinity related components, aggregate components, such as pH and solids, nutrients, organic components, including pesticides and endocrine disruptors, as well as quality variability. Relative differences in the proportion of concern for some quality characteristics were observed between the areas of different population density with those from the low population areas being more concerned than those from medium or high areas. Some users and providers observed changes in recycled water quality during distribution including nutrients, chlorine, solids, colour and odour. Some 52% of providers and 19% of current users propose to expand their usage and 30% of non-users propose to ...

This report represents a concise account of the experience I acquired on the various machines, equipment’s and laboratory procedures together with plant process during this period of attachment at the Alscon Township water Treatment Plant Facility 78 in Ikot Abasi.

The aim of this study was to compare the antimicrobial properties of a slow release noncorrosive chlorine dioxide with those of sodium dichloroisocyanurate to establish their possible use in the dental settings. Disinfectant solutions were prepared according to manufacturers' instructions and tested against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853, Streptococcus mutans NCTC 1044, Candida albicans ATCC 90028, Bacillus subtilis ATCC 15244 spores, Mycobacterium tuberculosis ATCC 25177, Mycobacterium avium subsp. avium ATCC 25291 and Hepatitis B virus using the Standard quantitative suspension test. The shelf-lives of the disinfectants were also determined. Both disinfectants killed all the test organisms within 30 seconds. B. subtilis spores were killed in 2 and 2.5 minutes by chlorine dioxide and sodium dichloroisocya nurate respectively. When diluted solutions of these disinfectants were stored in screw cap bottles, they retained their activity for at l...

Atmospheric chemistry is an important discipline for understanding air pollution and its impacts. This mini-review gives a brief history of air pollution and presents an overview of some of the basic photochemistry involved in the production of ozone and other oxidants in the atmosphere. Urban air quality issues are reviewed with a specific focus on ozone and other oxidants, primary and secondary aerosols, alternative fuels, and the potential for chlorine releases to amplify oxidant chemistry in industrial areas. Regional air pollution issues such as acid rain, long-range transport of aerosols and visibility loss, and the connections of aerosols to ozone and peroxyacetyl nitrate chemistry are examined. Finally, the potential impacts of air pollutants on the global-scale radiative balances of gases and aerosols are discussed briefly.

Unsur-unsur halogen (golongan VIIA) dalam sistem periodik meliputi F (fluorin), Cl (klorin), Br (bromin), I (iodin), dan At (astatin). Halogen sangat reaktif, sehingga di alam hanya ditemukan dalam bentuk senyawanya. Halogen berasal dari bahasa Yunani dari kata halo yang berarti garam, karena umumnya ditemukan dalam bentuk garam anorganik. Kelimpahan unsur-unsur halogen ini banyak terdapat di lautan. Unsur-unsur halogen mempunyai 7 elektron valensi pada subkulit ns2 np5. Konfigurasi elektron yang demikian membuat unsur-unsur halogen bersifat sangat reaktif. Halogen cenderung menyerap satu elektron membentuk ion bermuatan negatif satu (Ambarsari, 2020).

A sample preparation method based on sintering, followed by analysis by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) for the simultaneous determination of chloride and bromide in diverse and mixed solid wastes, has been evaluated. Samples and reference materials of known composition were mixed with a sintering agent containing Na(2)CO(3) and ZnO and placed in an oven at 560 degrees C for 1h. After cooling, the residues were leached with water prior to a cation-exchange assisted clean-up. Alternatively, a simple microwave-assisted digestion using only nitric acid was applied for comparison. Thereafter the samples were prepared for quantitative analysis by ICP-SFMS. The sintering method was evaluated by analysis of certified reference materials (CRMs) and by comparison with US EPA Method 5050 and ion chromatography with good agreement. Median RSDs for the sintering method were determined to 10% for both chlorine and bromine, and median recovery to 96% and 97%, respectively. Limits of detection (LODs) were 200mg/kg for chlorine and 20mg/kg for bromine. It was concluded that the sintering method is suitable for chlorine and bromine determination in several matrices like sewage sludge, plastics, and edible waste, as well as for waste mixtures. The sintering method was also applied for determination of other elements present in anionic forms, such as sulfur, arsenic, selenium and iodine.