Chlorine Substances Research Articles

Reaction-induced headspace strategy toward efficient available chlorine analysis in bleaching water products

In this study, with reaction-induced headspace strategy, a novel and convenient method for quantifying available chlorine in bleaching water product was developed. The analytical technique relies on the detection of carbon dioxide generated from the oxidation–reduction reaction between available chlorine substances (i.e., hypochlorite) and oxalate in the presence of a strong acid. The formed carbon dioxide is accurately measured using gas chromatography (GC) in a closed headspace vial. The results demonstrated that this analytical technique has high precision and and accuracy in detecting available chlorine. Additionally, the method offers low detection limits (limit of quantification (LOQ) = 0.19 μg/mL), and the recoveries ranged from 98.78 to 101.20% for added standards. With its efficiency and automation, this proposed reaction-induced headspace technique offers a fast and simple method for the routine estimation of available chlorine in bleaching water products, making it suitable for a wide range of applications including processing and quality monitoring.

East Asian summer monsoon delivers large abundances of very short-lived organic chlorine substances to the lower stratosphere

Deep convection in the Asian summer monsoon is a significant transport process for lifting pollutants from the planetary boundary layer to the tropopause level. This process enables efficient injection into the stratosphere of reactive species such as chlorinated very-short-lived substances (Cl-VSLSs) that deplete ozone. Past studies of convective transport associated with the Asian summer monsoon have focused mostly on the south Asian summer monsoon. Airborne observations reported in this work identify the East Asian summer monsoon convection as an effective transport pathway that carried record-breaking levels of ozone-depleting Cl-VSLSs (mean organic chlorine from these VSLSs ~500 ppt) to the base of the stratosphere. These unique observations show total organic chlorine from VSLSs in the lower stratosphere over the Asian monsoon tropopause to be more than twice that previously reported over the tropical tropopause. Considering the recently observed increase in Cl-VSLS emissions and the ongoing strengthening of the East Asian summer monsoon under global warming, our results highlight that a reevaluation of the contribution of Cl-VSLS injection via the Asian monsoon to the total stratospheric chlorine budget is warranted.

Effects of microplastics on DBPs formation under the chlorination of natural organic matters

Microplastics have attracted extensive attention and concern because they inflict damage on human beings and the environment. When the microplastics enter the water system, they inevitably flow into the water treatment system and encounter disinfectants during the disinfection procedure. Chlorine can react with microplastics to form different kinds of disinfection byproducts (DBPs). O-containing functional groups on the surface of microplastics may play a major role in DBP formation. Without O-containing functional groups, microplastics can also form DBPs but with totally different mechanisms. Reactive oxygen species (ROS, i.e., •OH) and reactive chlorine substances (RCS, i.e., Cl• and ClO•) may attack the microplastics and form DBP precursors. With relatively low surface area and very little pore volume, microplastics cannot affect the DBP formation between Suwannee River fulvic acid (SRFA) and chlorine. When SRFA exists, microplastics with few O-containing functional groups can hardly form DBPs because of the inhibition of ROS and RCS.

Комбинации CHCL и СHCL с пропаном и хладонами 125, 227ea как перспективные негорючие хладагенты

В данной работе рассмотрена проблема пожарной опасности применяемых в настоящее время хладагентов, предложено решение - создание негорючих смесевых композиций органических хлоридов с пропаном и хладонами 125, 227еа. Показана возможность увеличения доли короткоживущих компонентов в негорючих смесевых хладагентах, содержащих парниковые газы, с помощью создания тройных смесей. According to existing international agreements production of greenhouse gases must be drastically reduced in all sectors including refrigeration. It is known that refrigerants having short atmospheric lifetime are combustible. One of the methods to solve the problem of combustibility of refrigerants is to create noncombustible mixtures of combustible substance with an inhibitor of combustion. Such mixtures of organic chlorides with propane and CFH or CFH are investigated in this paper both theoretically and experimentally. Experimental equipment was specially adjusted to the combustion properties of the used chlorinated substances. It was obtained that CHCl и CНCl are strong inhibitors of combustion processes including self-inhibition of combustion of these substances themselves. Fluorinated hydrocarbons CFH and CFH are effective in suppression of combustion of dichloromethane and 1, 2-dichloroethane in air. As it follows from the obtained results, it is possible to reduce the content of the greenhouse component in the mixed refrigerant by 93% mass by creating noncombustible mixtures of dichlorides with CFH or CFH which are greenhouse gases. It was also revealed that CFH and CFH are stronger suppressants for combustion of CHCl and CНCl than for combustion of propane. Creation of triple noncombustible mixtures between CH, CHCl and CFH is advisable only when it is necessary to optimize energy efficiency of the refrigerant.

Anodic oxidation produces active chlorine to treat oilfield wastewater and prepare ferrate(VI)

This report describes an electrochemical method that encompasses the formation of active chlorine species and the synthesis of ferrate(Ⅵ). This process applies anodic oxidation to degrade oilfield wastewater pollutants, while simultaneously generating active chlorine from NaCl in the electrolyte. Ferrate(Ⅵ) is produced by utilizing the oxidizing properties of the active chlorine species in the presence of ferric ions, which are added after the electrolysis. The advantages of this method include (i) the relatively short electrolysis time required, (ii) the use of low current density conditions to produce active chlorine substances, and (iii) the formation of ferric hydroxide colloids, which can enhance the degradation of petroleum wastewater. The residual active chlorine in the system is used to synthesize ferrate(Ⅵ), which can help recycle waste. Specifically, the system achieves 89.4 % TOC reduction after 50 min of electrolysis with a current intensity of 1 A. Under the optimal dosage conditions (NaOH = 10 g·L−1, Fe(NO3)3 = 10 g·L−1), the concentration of ferrate(Ⅵ) produced after three hours of reaction is 1.08 mmol·L−1. The strategy described in this article demonstrates high efficiency towards removing organic pollutants in oilfield wastewater, and provides a waste resource recycling strategy.

Application development for accidental pollution assessment on chemical manufacturers (pollution from chemical waste)

Considering that in recent decades there has been a dramatic increase in the amount of industrial disasters, among which accidents on chemical facilities retain a significant place, forecasting tasks and accident consequence assessment on hazardous chemical facilities are analyzed in this paper. The task of the emergency area size determination, as well as the determination of building destruction level, and the facility personnel and public expenses. The objective of the paper is to review the existing methodologies of forecasting and create a software system for accident consequence forecasting on hazardous chemical facilities. Methodology. The analysis of different methods of damage estimation, conducted by the author, allowed for the general scheme of damage from accidents on potentially hazardous facilities estimation to be made. Furthermore, the author analyzed potential objects of chemical pollution in the Saratov region. The paper demonstrates phases of theoretical development and implementation of software program for accident consequence assessment and modeling on hazardous chemical facilities. The developed software system has a connection with Google Maps GMap.NET, which allows to visualize the obtained assessment results. Results. The result of practical implementation of the application developed by the author is an accident model for a facility, using chlorine substances, the amount of pollution measurement and territory pollution determination. Conclusion. The paper shows that the implementation of the program system developed in the work of organizations will help the heads to minimize possible losses of working personnel, public and organization financial losses.. The author notes that the application developed is free from the main disadvantages of existing programs, more specifically, the absence of the possibility to estimate the physical damage caused by the accident.

Evaluation of Low Cost-Activated Carbon Produced from Waste Tyres Pyrolysis for Removal of 2-Chlorophenol

A low cost Activated Carbon (AC) was prepared by using waste tyres as raw material for the removal of 2-chlorophenol (2-CP). The AC adsorbent was prepared and activated by pyrolysis process at 900 ºC under constant nitrogen flow. The physical properties of the AC produced was characterized using X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), Field Emission Scanning Electron Microscopy (FESEM), and Fourier Transform Infra Red (FTIR). The influence of initial adsorbate concentration, pH and adsorbent dosage on the removal of 2-CP in the batch-operational mode at ambient temperature were also investigated. The results obtained showed the AC presence of an amorphous carbon with high BET surface area and a total pore volume of 208 m2.g-1 and 0.5817 cm3, respectively. The highest adsorption capacity of 2-CP by the AC absorbent was achieved at an initial concentration of 10 mg.L-1, pH 5, and adsorbent dosage of 0.5 g in the first 10 min of contact time. This finding proves that the low cost-AC produced from waste tyres can be utilized for an effective removal of chemical plant wastewater containing toxic chlorine substances. Copyright © 2019 BCREC Group. All rights reserved

Removal of chlorobenzene using a sequential adsorption–plasma catalytic system over Ag‐, Ce‐ and Mn‐modified activated carbon catalysts

AbstractBACKGROUNDA dielectric barrier discharge reactor coupled with a series of activated carbon (AC) catalysts was applied to remove low concentrations of chlorobenzene. The catalysts were prepared via an impregnation method and their adsorption capacity and plasma‐catalytic ability examined in a sequential adsorption–plasma oxidation process.RESULTSAg/AC had the longest breakthrough time and highest breakthrough capacity among the catalysts studied. At the discharge stage, the Ag/AC catalyst had the highest CO2 yield, chlorobenzene mineralization rate and carbon balance, and the lowest emission of chlorobenzene when compared with the other catalysts under the same conditions. However, the Ag/AC catalyst exhibited the worst reducing ozone generation performance, while the Mn/AC catalyst showed the best ozone decomposition ability. The organic intermediates produced using Ag/AC and Ce/AC were simpler and in lower concentrations than those formed using Mn/AC. The adsorption capacity and catalytic activity of the Ag/AC catalyst showed no obvious decrease after five cycles. Fourier transform infrared and scanning electron microscopy–energy dispersive spectroscopy analyses after the reaction showed that some nitrogen organic intermediates and chlorine substances produced via the degradation of chlorobenzene were adsorbed onto the catalyst surface.CONCLUSIONSAg/AC exhibited a longer breakthrough time, higher breakthrough capacity, higher CO2 yield, less chlorobenzene emission and better carbon balance when compared with the other catalysts. © 2019 Society of Chemical Industry

Reviewing Interventions against Enterobacteriaceae in Broiler Processing: Using Old Techniques for Meeting the New Challenges of ESBL E. coli?

Extended-spectrum beta-lactamase- (ESBL-) producing Enterobacteriaceae are frequently detected in poultry and fresh chicken meat. Due to the high prevalence, an impact on human colonization and the spread of antibiotic resistance into the environment is assumed. ESBL-producing Enterobacteriaceae can be transmitted along the broiler production chain but also their persistence is reported because of insufficient cleaning and disinfection. Processing of broiler chickens leads to a reduction of microbiological counts on the carcasses. However, processing steps like scalding, defeathering, and evisceration are critical concerning fecal contamination and, therefore, cross-contamination with bacterial strains. Respective intervention measures along the slaughter processing line aim at reducing the microbiological load on broiler carcasses as well as preventing cross-contamination. Published data on the impact of possible intervention measures against ESBL-producing Enterobacteriaceae are missing and, therefore, we focused on processing measures concerning Enterobacteriaceae, in particular E. coli or coliform counts, during processing of broiler chickens to identify possible hints for effective strategies to reduce these resistant bacteria. In total, 73 publications were analyzed and data on the quantitative reductions were extracted. Most investigations concentrated on scalding, postdefeathering washes, and improvements in the chilling process and were already published in and before 2008 (n=42, 58%). Therefore, certain measures may be already installed in slaughterhouse facilities today. The effect on eliminating ESBL-producing Enterobacteriaceae is questionable as there are still positive chicken meat samples found. A huge number of studies dealt with different applications of chlorine substances which are not approved in the European Union and the reduction level did not exceed 3 log10 values. None of the measures was able to totally eradicate Enterobacteriaceae from the broiler carcasses indicating the need to develop intervention measures to prevent contamination with ESBL-producing Enterobacteriaceae and, therefore, the exposure of humans and the further release of antibiotic resistances into the environment.

212 Conversion of Municipal Solid Waste into Fuel for Co-firing Application with Coal by Hydrothermal Treatment : Part I : Chlorine Removal

This paper describes the application of innovative hydrothermal technology on local municipal solid waste (MSW) to produce low chlorine content solid co-firing fuel with coal. Raw MSW was treated at temperatures ranging from 210 to 235℃ with 30 to 90 minutes holding period. The process yielded slump products which were then naturally dried to 5% moisture content, resulted in dry products with the heating value up to 24MJ/kg (dry base). Organic chlorine compound from plastic in MSW was converted to inorganic chlorine and reduced to 0.2% level. The inorganic chlorine substances were then removable by water washing at 1:8 product-water ratio (dry base) and vacuum filtration. With these features, the innovative hydrothermal treatment would then be a good alternative for MSW treatment and conversion into coal co-firing fuel.

The Structure of Water Induced by Specific Ceramics Treatment and Effects of Treated Water in View of Some Biological Aspects

The structure of water induced by a high-temperature sintered kaolinite ceramics treatment was studied in view of thermally stimulated depolarized current (J) and temperature profiles (TSDC analysis) on the iced treated water and 1H-Nuclear Magnetic Resonance (NMR) spectrometry on the treated water as well as some physical properties of the sintered ceramics. In addition, some biological effects of the treated water were examined to give indirect evidences for the proposed water structure. The treated water were positively charged based on essentially the formation of electric double layer interface between the ceramics surface and water flow, without any absorption-desorption phenomena to substances contained in water to be treated by the ceramics. The positive charge was indirectly affirmed by TSDC and 1H-NMR analyses on ionexchanged water and for the drinking water. The water structure derived by the existence of chlorine substances was apparently disappeared from 1H-NMR spectrum, probably by the apparent neutralization or accumulation of chlorine substances through interaction with positive charge. This phenomenon seemed to be closely related with the fact that absorption of chlorine ion through a vegetable root was greatly depressed when the treated water by the ceramics was used. The treated water was also proved to restrict the growth of E. coli in poor nutritional culture media and the production of bacterial cellulose by CFJ-002 (New bacterium cellulose-producing microorganism, an enterobacter) stock, and to suppress the oxidation action of hydrogen peroxide.

Scientific activities of Euro Chlor in monitoring and assessing naturally and man-made organohalogens

In this paper a review of the scientific activities and research programmes carried out by Euro Chlor, the European Federation of chlor-alkali producers is presented according to two main axes: marine risk assessments with statistical analysis of monitoring data, temporal trends of emission levels and environmental concentrations. The methodology applied in each field is briefly presented and then illustrated by several practical examples. As a large part of the uncertainties in assessing the risk of a chemical to a given species or ecosystem often comes from the difficulty in evaluating the exposure level, Euro Chlor has chosen to use a monitoring approach, the exposure level being estimated from a statistical analysis of measured concentrations levels in water and sediment from rivers, estuaries and coastal areas. As the modelling approach often used by the authorities to estimate the predicted environmental concentration value is starting from roughly estimated emission levels, Euro Chlor collated emissions data from about 80 production plants in order to reduce the uncertainty associated with the default values introduced in the modelling approach. A brief review of the European emission levels for chlorinated organic substances is given as well as the temporal trends of both emission and environmental levels. A methodology to quantify the trends in measured concentrations at local and regional scales is briefly described. The observed decreasing trends demonstrate the continuous progress made by the Euro Chlor member companies in protecting the environment. Finally, the problems linked to the simultaneous presence in the environment of naturally and man-made chlorinated substances are briefly reviewed. To stimulate further research in the field, two key questions are raised which have not yet found a satisfactory answer: how to quantify natural background levels and how to quantify global persistence in the environment?

Analysis of halogenated C1/C2-trace compounds in marine atmosphere.

Patterns of volatile ECD-active substances in marine air at the ultra trace level were investigated. The protocol used carbon based adsorbents, thermodesorption and thick film HRGC-ECD together with a second ECD in line with oxygen doped make-up gas. The latter ECD mode leads to an increased sensitivity for chloromethane. dichloromethane, and other important chlorinated substances with an otherwise low response at an ECD driven with oxygen-free nitrogen or argon/methane. The experimental set-up is easily to employ. Air samples were taken on two cruises of the German research vessel R/V "Polarstem" in the Atlantic Ocean to determine the background pattern of all volatile halocarbons from CF3Cl to CHI3 in marine air.

Combining SFA and LCA

SummaryThis article describes a method that combines substance flow analysis (SFA) and life‐cycle assessment (LCA). It was used to provide a focus in the heated Swedish polyvinylchloride (PVC) debate. For Sweden's PVC chain, all emissions related to PVC were inventoried and translated into LCA‐theme scores. The theme scores were compared with total theme scores for all Swedish processes and were benchmarked on the basis of PVC's contribution to Sweden's gross national product (GNP). Mass flows oftwo PVC additives, lead and organotin, were compared with the total use of these metals in Sweden. PVC's contribution to global warming, smog formation, and waste volume was equal to or less than the benchmark. After implementation of planned measures, emissions of the toxic substances dioxins, mercury, and lead will be below the benchmark. We recommend that the Swedish PVC debate concentrate on the uncertainties of the effects of phthalates, small process emissions of persistent chlorinated substances (PBTs), lead and organotin in landfilled PVC, and emissions from PVC in accidental fire

Activities of ligninolytic enzymes of the white rot fungus, phanerochaete chrysosporium and its recalcitrant substance degradability

The factors influencing the activities of extracellular ligninolytic enzymes synthesized by white rot fungus,Phanerochaete chrysosporium , were investigated by batch culture experiments. The LiP activity was maximal under the nitrogen-sufficient condition, compared with the activities under both conditions of the nitrogen-limited and nitrogen-excess. The manganese-dependent peroxidase (MnP) activity was highest under nitrogen-limited condition. Veratryl alcohol was found to be the most important substrate enhancing lignin peroxidase (LiP) activity in carbon-limited medium. The decolorization of azo dye (Reactive Red 22) by P. chrysosporium in the presence of both LiP and MnP under carbon-limited condition was greater than that in the presence of MnP under nitrogen-limited condition. Two chlorinated substances (2,6-DCP and MCPA) were degraded under conditions of nitrogen-limitation and notrogen-sufficiency. The azo dyes were also decolorized by the crude extracellular ligninolytic enzymes from P. chrysosporium.

Activities of ligninolytic enzymes of the white rot fungus, Phanerochaete chrysosporium and its recalcitrant substance degradability

The factors influencing the activities of extracellular ligninolytic enzymes synthesized by white rot fungus, Phanerochaete chrysosporium, were investigated by batch culture experiments. The LiP activity was maximal under the nitrogen-sufficient condition, compared with the activities under both conditions of the nitrogen-limited and nitrogen-excess. The manganese-dependent peroxidase (MnP) activity was highest under nitrogen-limited condition. Veratryl alcohol was found to be the most important substrate enhancing lignin peroxidase (LiP) activity in carbon-limited medium. The decolorization of azo dye (Reactive Red 22) by P. chrysosporium in the presence of both LiP and MnP under carbon-limited condition was greater than that in the presence of MnP under nitrogen-limited condition. Two chlorinated substances (2,6-DCP and MCPA) were degraded under conditions of nitrogen-limitation and notrogen-sufficiency, The azo dyes were also decolorized by the crude extracellular ligninolytic enzymes from P. chrysosporium.

Scientific Principles for Evaluating the Potential for Adverse Effects from Chlorinated Organic Chemicals in the Environment

The term chlorinated chemicals is used to describe diverse groups of chemicals of varying chemical structure, including those used in water disinfection, as well as numerous aliphatic, aromatic, and polycyclic chlorinated substances. This report elaborates a number of scientific principles that govern the evaluation of the potential for chlorinated organic chemicals to cause adverse effects on the environment and to human health. The purpose of the report is to demonstrate the importance of applying these scientific principles in the evaluation of potential adverse effects of chlorinated organic chemicals. The four major principles upon which such a scientific analysis must be based are: (1) the fate and biological activity of a compound are determined by the chemical properties of the compound; (2) compounds do not show adverse effects below certain threshold concentrations, and the magnitude of response is related to dose; (3) inherent metabolic processes allow organisms to accommodate low doses of chlorinated organic chemicals; (4) observations associated with the presence of a certain compound must be biologically plausible effects, based on the specificity of the compound's activity in experimental systems. With respect to the first of these principles, there is abundant scientific evidence that the physical and chemical properties of chlorinated organic chemicals govern their bioaccumulative potential, toxicological properties, and thus their potential behavior and effects in the environment. Chemicals that have low solubility in water are highly lipophilic and have low vapor pressure, tend to accumulate in biological systems, and degrade slowly in the environment. Chlorinated organic chemicals that possess these characteristics include those having a carbon ring structure and multiple chlorine substitution. Other chlorinated organic chemicals with lesser degrees of chlorine substitution, such as 2,4-dichlorophenoxyacetic acid (2,4-D), trichlorophenol, chloroform, and dichloroethane, do not share the physical and chemical properties of the high molecular weight, cyclic, polychlorinated compounds and, as such, do not have the same potential to bioaccumulate. These differences among chlorinated organic chemicals with respect to their physical and chemical properties and behavior in the environment preclude the generalization that all organic chemicals containing chlorine behave similarly in the environment and act as persistent, bioaccumulative chemicals. The reactivity of chlorinated organic chemicals and hence their potential to produce biological effects depends on their specific molecular features. The substitution of chlorine into an organic molecule may increase or may reduce its biological activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Bestimmung von flüchtigen chlorkohlenwasserstoffen mit reaktionsgaschromatographie

Determination of volatile chlorinated hydrocarbons by reaction gas chromatography A new method for the determination of volatile chlorinated hydrocarbons is described, which makes it possible to convert water quantitatively to acetylene after direct injection of aqueous samples onto a calcium carbide-precolumn. Acetylene produces a sharp peak which can be easily separated from the chlorinated hydrocarbons and the electron-capture detection is not affected by greater amounts of water. Different types of precolumns were tested and the most convenient conditions for a quantitative conversion of water were determined. The application of the method shows, that six important chlorinated substances can be analized simultaneously and detection limits (3 μg/l, except methylene chloride), standard deviation and recovery were satisfactory.