Inorganic Chlorine Compounds Research Articles

Low-temperature dechlorination methods for pyrolysis oil of municipal plastic waste

Pyrolysis oil produced from municipal plastic waste can be utilized as fuel and various valuable chemicals as an alternative to petroleum. However, pyrolysis oil usually contains a relatively high concentration of chlorinated compounds, obstructing its utilization in the chemical industry. The present research reveals that pyrolysis oil contains inorganic chlorine and organochlorine compounds, and differentiated approaches should be considered to remove Cl from covalent and ionic chlorine linkages. Transition metal-based ZSM-5 catalysts showed remarkable dechlorination performance via mild C-Cl cracking of 1-chlorooctane and 4-chlorotoluene at 180 °C or below. The neutralization method of mixing pyrolysis oil with an alkaline solution quickly eliminated ionic chlorine from inorganic chlorine compounds, reducing Cl concentrations by up to 70 % at temperature below 40 °C. Based on the different dechlorinating pathways, an ideal combination of these two methods was suggested to enhance chlorine removal efficiency from pyrolysis oil.

Evaluation of phytotoxicity of disinfectants used for manure disinfection

Manure as an organic fertilizer in practice of agriculture is allowed to use only if it does not contain pathogenic microorganisms. Upon detection in manure and chicken droppings of pathogens of infectious diseases is carried out their disinfection. Choosing method of disinfection is carried out at the direction of veterinary service taking into account danger of arising of epizootic situation, type of pathogen of disease, presence and type of chemical reagents and technical means. For disinfection of animal by-products by chemical method we use a large number of disinfecting agents potentially hazardous for the environment which is associated with the content in their composition of xenobiotics, in particular aldehydes, chlorine, phenols, etc. The paper presents results of biotesting of soils polluted by disinfecting agents used for disinfection animal by-products, in particular, bioethanol, Novochlor-Extra (contain such active substances how inorganic chlorine compounds and alkali) and Dezaktin (organic chlorine compounds, anion SAS and sodium tripolyphosphate). The assessment was carried out under laboratory conditions through biotesting with the use of spring barley (Hordeum vulgare L.). It is established, that after five-day cultivation of barley seeds in soils containing 1.0, 10.0 and 100.0 mg/kg of such agents as bioethanol, Novochlor-Extra and Dezaktin there was gradual reduction of mass of stem to 10.2% compared to a control. When the content in soils was 1.0, 10.0 and 100.0 mg/kg of investigated disinfectants gradual reduction of length of stem of barley by an average of 12.2% was observed. At pollution of soil investigated agents in the number of 1.0, 10.0 and 100.0 mg/kg we observed the small increase of length of longest of root by an average of 7.8%, which indicates to stimulating influence on the growth of root system and absence of phytotoxicity. When the content of disinfectants bioethanol and Novochlor-Extra in soils was in a quantity of 1000 mg/kg, there was reduction of mass, length of stem and longest root of an average of 19.1, 30.5 and 16.8%, respectively. At pollution of soil at the level of 1000 mg/kg agent of Dezactin we observed reduction of mass of stem to 61.8%, its length on 72.0% and length of longest of root to 67.4% that demonstrated to phytotoxic influence. At the hit of disinfectants with disinfected animal by-products in soils in a quantity of ≥1000 mg/kg it is possible to predict negative impact on morphometric indicators of plant what probably will lead to worsen of their development. The method of determination of pollution of soils by delay growth of root of plants is informative express method for ecological assessment of content in them the disinfectants used for disinfection of animal by-products.

Validation of SMILES HCl profiles over a wide range from the stratosphere to the lower thermosphere

Abstract. Hydrogen chloride (HCl) is the most abundant (more than 95 %) among inorganic chlorine compounds Cly in the upper stratosphere. The HCl molecule is observed to obtain long-term quantitative estimations of the total budget of the stratospheric chlorine compounds. In this study, we provided HCl vertical profiles at altitudes of 16–100 km using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) from space. The HCl vertical profile from the upper troposphere to the lower thermosphere is reported for the first time from SMILES observations; the data quality is quantified by comparison with other measurements and via theoretical error analysis. We used the SMILES level-2 research product version 3.0.0. The period of the SMILES HCl observation was from 12 October 2009 to 21 April 2010, and the latitude coverage was 40∘ S–65∘ N. The average HCl vertical profile showed an increase with altitude up to the stratopause (∼ 45 km), approximately constant values between the stratopause and the upper mesosphere (∼ 80 km), and a decrease from the mesopause to the lower thermosphere (∼ 100 km). This behavior was observed in all latitude regions and reproduced by the Whole Atmosphere Community Climate Model in the specified dynamics configuration (SD-WACCM). We compared the SMILES HCl vertical profiles in the stratosphere and lower mesosphere with HCl profiles from Microwave Limb Sounder (MLS) on the Aura satellite, as well as from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) on SCISAT and the TErahertz and submillimeter LImb Sounder (TELIS) (balloon borne). The TELIS observations were performed using the superconductive limb emission technique, as used by SMILES. The globally averaged vertical HCl profiles of SMILES agreed well with those of MLS and ACE-FTS within 0.25 and 0.2 ppbv between 20 and 40 km (within 10 % between 30 and 40 km; there is a larger discrepancy below 30 km), respectively. The SMILES HCl concentration was smaller than those of MLS and ACE-FTS as the altitude increased from 40 km, and the difference was approximately 0.4–0.5 ppbv (12 %–15 %) at 50–60 km. The difference between SMILES and TELIS HCl observations was about 0.3 ppbv in the polar winter region between 20 and 34 km, except near 26 km. SMILES HCl error sources that may cause discrepancies with the other observations are investigated by a theoretical error analysis. We calculated errors caused by the uncertainties of spectroscopic parameters, instrument functions, and atmospheric temperature profiles. The Jacobian for the temperature explains the negative bias of the SMILES HCl concentrations at 50–60 km.

Chloride-mediated co-formation of 3-monochloropropanediol esters and glycidyl esters in both model vegetable oils and chemical model systems

3-Monochloropropanediol esters (3-MCPDEs) and glycidyl esters (GEs) with high toxicity have drawn global concerns due to their widespread occurrence in refined oils and oil-based foods. The effect mechanisms of organic chlorine compound lindane, inorganic chlorine compounds tetra-n-butylammonium chloride (TBAC) and sodium chloride (NaCl) on the formation of 3-MCPDEs and GEs were investigated in model oils and chemical models at 240 °C. Results showed that 3-MCPDEs contents increased with the addition of lindane and TBAC, whereas, surprisingly, GEs presented the same tendency as the results of 3-MCPDEs. This suggested that although chlorine compounds were not involved in the formation reaction of GEs, they could also promote GEs formation. Chemical model experiments confirmed that the presence of chlorine compounds led to the transformation of GEs to 3-MCPDEs and conversely 3-MCPDEs could also transform to GEs. The latter transformation rate from 3-MCPDEs to GEs was higher than the former, which might account for the fact that chlorine compounds promoted GEs formation. Additionally, it was also observed that solid NaCl did not induce the increase of 3-MCPDEs and GEs levels in chemical models, suggesting that the chlorine in NaCl, different from lindane and TBAC, was not available for 3-MCPDEs formation. The present findings give novel insights into the interactions between 3-MCPDEs and GEs formation mechanisms, which offer the theoretical basis for efficient and simultaneous inhibition of 3-MCPDEs and GEs.

Microbial Synthesis and Transformation of Inorganic and Organic Chlorine Compounds.

Organic and inorganic chlorine compounds are formed by a broad range of natural geochemical, photochemical and biological processes. In addition, chlorine compounds are produced in large quantities for industrial, agricultural and pharmaceutical purposes, which has led to widespread environmental pollution. Abiotic transformations and microbial metabolism of inorganic and organic chlorine compounds combined with human activities constitute the chlorine cycle on Earth. Naturally occurring organochlorines compounds are synthesized and transformed by diverse groups of (micro)organisms in the presence or absence of oxygen. In turn, anthropogenic chlorine contaminants may be degraded under natural or stimulated conditions. Here, we review phylogeny, biochemistry and ecology of microorganisms mediating chlorination and dechlorination processes. In addition, the co-occurrence and potential interdependency of catabolic and anabolic transformations of natural and synthetic chlorine compounds are discussed for selected microorganisms and particular ecosystems.

On the Environmental Hazard of Burning Organic Waste in the Presence of Chlorine Compounds

The problems of formation of toxic chlororganic compounds during waste incineration in the presence of organic and inorganic chlorine compounds are considered. It is shown that the radical mechanism of pyrolysis leads to different products with different composition of the initial substances. It was found that the greatest environmental danger is the joint burning of chlororganic and aromatic compounds. When burning polyvinyl chloride together with other polymeric materials, especially the aromatic structure, not only light chlororganic compounds are formed, but also highly toxic carbonyl chloride and chlor-furan. The formation of the above compounds represents a potential danger of further chemical conversions and the production of chlorinated dioxin compounds. It is proposed to prevent the formation of highly toxic compounds from the burning of polyvinyl chloride, its mandatory separation from the solid municipal waste stream and its separate processing by flameless methods.

Distribution and Identification of Chlorides in Distillates from YS Crude Oil

This study investigated the distribution and identification of chlorides in distillates from YS crude oil on the basis of true boiling point (TBP) distillation technology. YS crude oil was categorized into low-acid light crude oil with total chlorine content of 10.019 mg/L, in which the inorganic chlorine and organochlorine contents were determined as 5.870 and 4.419 mg/L, respectively. A total of 21 distillates and one residual oil (>500 °C) were obtained by TBP distillation. The organochlorine compounds were observed as predominant one among all distillates instead of inorganic chlorine compounds. The organochlorine content of 141.1 mg/L within the boiling range of 39.2 °C (initial boiling point, IBP) to 60 °C was the maximum when compared with that in other distillates. However, the organochlorine content in distillates gradually decreased with increasing boiling range from IBP to 260 °C. Meanwhile, low-boiling chlorides, such as carbon tetrachloride and trichloroethylene, were identified from the distillates (<300 °C) via gas chromatography with electron capture detection (ECD). Accordingly, these low-boiling chlorides coexisted in almost all distillates (<300 °C). By contrast, high boiling components with electronegativity were observed only in the boiling range of 220 to 300 °C, and these species increased with the increasing boiling range of distillates.

Decontamination by ultrasound application in fresh fruits and vegetables

Changes in consumer eating habits, health concerns, and convenient and practical foods have led to an increased demand for fruit and vegetable products. Food safety is essential considering that there are reports of outbreaks involving the consumption of fruits and vegetables contaminated with pathogens. Washing associated with sanitizer procedure is considered as a critical step to satisfy hygienic and sanitary requirements and maintain the sensory and nutritional characteristics of fruits and vegetables. Chemical compounds are widely applied to clean and sanitize fresh fruits and vegetables, and some of these chemicals, such as the inorganic chlorine compounds, produce by-products that are dangerous to human health. The use of ultrasound is a technology that is gaining ground in the food industry. Ultrasound is a form of energy generated by sound waves at frequencies that are too high to be detected by the human ear. In ultrasound, the removal of dirt and food residues from surfaces and the inactivation of microorganisms occur as a consequence of cavitation, which is the formation, growth and collapse of bubbles that generate a localized mechanical and chemical energy. There are indications that this technology can be used in the food industry, alone or associated with chemical sanitizers. In this paper, we discuss the principles, mechanisms and effects of ultrasound on fruits and vegetables as a sanitization technology.

Data analysis of the flue gas emissions in the thermal-power plant firing fuel oil and natural gas

The thermal-power plant with combined heat and power (CHP) production located in the city of Zrenjanin (Serbia) is powered by two steam boilers with nominal power of 280 MW each. Considering the problem of increasing pollutant emissions that occur during fossil-fuel combustion process, which is recognized as an arising problem in the CHP Zrenjanin, the accredited Laboratory has been carrying out monitoring and control of the emission production. The emissions have been measured during winter season on boiler B1 for five working regimes of burners, by adjusting the fuel ratio between natural gas and fuel oil. The measurement has been done regarding carbon monoxide, sulphur dioxide, nitrogen oxides (NOx), particulate matter (PM), gaseous inorganic chlorine compounds denoted as hydrogen chloride, and gaseous inorganic fluoride compounds denoted as hydrogen fluoride. Data acquired from those measurements have shown that all parameters except NOx and PM did not exceed emission limits defined under current regulatory statute. According to data analysis of the flue gas emissions, first preventive actions are recommended, then possible actions that could be taken during combustion process, and as last but not least, actions that have to be applied in case when emission problems appears. Regarding CHP control and management problems, some advices are given emphasizing an integral approach to the analysis and optimization of the CHP as the best solution.

Effects of inorganic chlorine source on dioxin formation using fly ash from a fluidized bed incinerator

Chlorine source is indispensable for polychlorinated dibenzo- p-dioxin and furan (PCDD/F) formation during municipal solid waste (MSW) incineration. Inorganic chlorine compounds were employed in this study to investigate their effects on PCDD/F formation through heterogeneous synthesis on fly ash surfaces. A fly ash sample obtained from a fluidized bed incinerator was sieved to different size fractions which served as the PCDD/F formation sources. The capability of different metal chlorides which facilitate the formation of PCDDs/Fs was found to follow the trends: Na < Mg < K < Al < Ca, when two particle fractions of >177 μm and 104–125 μm were used in the experiments. However, the capability of NaCl, MgCl 2 and KCl did not seem much different from each other, whereas CaCl 2and AlCl 3 were much more active in PCDD/F formation. NaCl and MgCl 2 were relatively effective to produce more PCDDs, while KCl, AlCl 3 and CaCl 2 generated more PCDFs during heterogeneous reactions occurring on fly ash. 2,3,7,8-TCDF was the most significant contributor to the toxicity of the PCDDs/Fs formed from inorganic chlorine sources. Decreasing the sizes of fly ash particles led to more active formation of PCDDs/Fs when NaCl was used as inorganic chlorine in the experiment. The highest PCDDs/Fs produced from particles with size <37 μm, while the lowest PCDDs/Fs produced from particles with size >177 μm. The toxicity generally increased with decreasing size of the fly ash particles. The formation of PCDDs was mainly facilitated by the two size fractions, 104–125 μm and <37 μm, while the formation of PCDFs was favored by the two other size fractions, >177 μm and 53–104 μm.

Water-based chlorination treatment of SBS rubber soles to improve their adhesion to waterborne polyurethane adhesives in the footwear industry

Solutions of trichloroisocyanuric acid (TCI) in different organic solvents are commonly employed in the footwear industry to improve the adhesion of SBS (styrene-butadiene-styrene) rubber soles to polyurethane adhesive. To avoid the use of organic solvents in the chlorinating solutions, several water-based chlorinating treatments were investigated in this study: (i) inorganic chlorine compounds (HCl-acidified sodium hypochlorite solution; free active chlorine (FAC) = 47.8 g/l); (ii) organic chlorine donors (aqueous solution of 3 wt% TCI/H2O, and ethanol solutions of 3 wt% HD (1,3-dichloro-5,5-dimethylhydantoine), or NCS (N-chlorosuccinimide); (iii) organic chlorine donor salts (aqueous solutions containing 3 wt% DCI (sodium dichloro isocyanurate), CB (chloramine B, N-chloro-sodium-phenylsulphenamide), or CT (chloramine T, N-chloro-sodium-p-toluenesulphenamide). The surface modifications produced by treatment of SBS rubber with the aqueous chlorinating agents were compared with those obtained by using the current solvent-based chlorinating treatment (3 wt% TCI/MEK). The FAC concentration and the chlorine stability in the solutions were determined by iodine titration, and the SBS rubber surface pH was determined with a flat pH probe. The surface modifications on the SBS rubber were analyzed by ATR-IR spectroscopy, XPS, contact-angle measurements and SEM. The adhesion properties were evaluated by T-peel strength tests on treated SBS rubber/waterborne polyurethane adhesive/roughened leather joints. The failed surfaces obtained after peel tests were analyzed by ATR-IR spectroscopy to precisely assess the locus of failure of the adhesive joints. The nature of the modifications produced on the SBS rubber surface depended on the chlorinating system used, the SBS rubber surface pH value, and the free active chlorine concentration of the chlorinating solution. The most effective chlorinating agents were TCI/H2O and HD/EtOH, but they were not stable over time due to quick chlorine evolution. Treatment with NaClO/HCl and DCI/H2O provided acceptable adhesive strength values although there was fast chlorine evolution in the NaClO/HCl solution; the free active chlorine concentration in the DCI/H2O solution was stable for at least 4 days after preparation. Finally, the treatment with NCS/EtOH, CB/H2O and CT/H2O did not chemically modify the SBS rubber surface, so the adhesion to polyurethane adhesive was not improved.

Simulation of ozone depletion in spring 2000 with the Chemical Lagrangian Model of the Stratosphere (CLaMS)

Simulations of the development of the chemical composition of the Arctic stratosphere for spring 2000 are made with the Chemical Lagrangian Model of the Stratosphere (CLaMS). The simulations are performed for the entire Northern Hemisphere on four isentropic levels (400–475 K). The initialization in early February is based on observations made from satellite, balloon and ER‐2 aircraft platforms. Tracer‐tracer correlations from balloon‐borne cryosampler (Triple) and ER‐2 measurements, as well as tracer‐PV correlations, are used to derive a comprehensive hemispherical initialization of all relevant chemical trace species. Since significant denitrification has been observed on the ER‐2 flights, a parameterization of the denitrification is derived from NOy and N2O observations on board the ER‐2 aircraft and the temperature history of the air masses under consideration. Over the simulation period from 10 February to 20 March, a chemical ozone depletion of up to 60% was derived for 425–450 K potential temperature. Maximum vortex‐averaged chemical ozone loss rates of 50 ppb d−1 or 4 ppb per sunlight hour were simulated in early March 2000 at the 425 and 450 K potential temperature levels. We show comparisons between the measurements and the simulations for the location of the ER‐2 flight paths in late February and March and the location of the Triple balloon flight. The simulated tracer mixing ratios are in good agreement with the measurements. It was not possible to reproduce the exact details of the inorganic chlorine compounds. The simulation agrees with ClOx observations on the Triple balloon flight but overestimates for the ER‐2 flights. The simulated ozone depletion agrees with estimates from other observations in the 425 and 450 K levels, but is underestimated on the 475 K level.

Unexpectedly high concentrations of molecular chlorine in coastal air

The fate of many atmospheric trace species, including pollutants such as nitrogen oxides and some volatile organic compounds, is controlled by oxidation reactions. In the daytime troposphere, these reactions are dominated by photochemically produced OH radicals; at night and in polluted environments, NO3 radicals are an important oxidant1. Ozone can contribute to the oxidation of atmospheric species during both day and night1. In recent years, laboratory investigations2,3,4, modelling studies5,6,7, measured Cl deficits in marine aerosols8 and species-nonspecific observations9,10,11 of gaseous inorganic chlorine compounds other than HCl have suggested that reactive halogen species may contribute significantly to—or even locally dominate—the oxidative capacity of the lower marine troposphere. Here we report night-time observations of molecular chlorine concentrations at a North American coastal site during onshore wind flow conditions that cannot be explained using known chlorine chemistry. The measured Cl2 mixing ratios range from <10 to 150 parts per 1012 (p.p.t.), exceeding those predicted5 for marine air by more than an order of magnitude. Using the observed chlorine concentrations and a simple photochemical box model, we estimate that a hitherto unrecognized chlorine source must exist that produces up to 330 p.p.t. Cl2 per day. The model also indicates that early-morning photolysis of molecular chlorine can yield sufficiently high concentrations of chlorine atoms to render the oxidation of common gaseous compounds by this species 100 times faster than the analogous oxidation reactions involving the OH radical, thus emphasizing the locally significant effect of chlorine atoms on the concentrations and lifetimes of atmospheric trace species in both the remote marine boundary layer and coastal urban areas.

The importance of heterogeneous bromine chemistry in the lower stratosphere

Heterogeneous conversion of bromine reservoirs (BrONO2, HOBr) on the surface of aerosol particles in the lower stratosphere has limited effect on the concentrations of reactive bromine radicals (Br, BrO). However, the heterogeneous hydrolysis of BrONO2 on sulfate aerosol particles, which produces HOBr, leads to the enhancement of the abundance of hydroxyl radicals, and consequently modifies the partitioning between inorganic chlorine compounds. Further, because of the enhanced abundance of HOBr, the heterogeneous reaction between HOBr and HCl(s) converts significant amounts of inactive chlorine (HCl) into reactive chlorine (ClO), especially during post‐volcanic periods. These processes could partially explain the unexpected high ClO/HCl and ClONO2/HCl concentration ratios at 20 km reported after the eruption of Mt. Pinatubo (1991), and could have contributed to the substantial ozone depletion observed after the large volcanic eruptions of the 1980's and 1990's. Our model simulations suggest that, owing to the heterogeneous hydrolysis of BrONO2 and the reaction HOBr+HCl(s) on sulfate aerosols, the increase in total bromine loading from 1960 (12 pptv) to 1990 (21 pptv) has led to enhanced concentrations of ClO, and consequently to an ozone depletion of 2–3% in the lower stratosphere at mid and high latitudes under post‐volcanic conditions.

Development of a Laboratory Method for Estimation of Hydrogen Chloride Emission Potential of Incinerator Feed Materials

ABSTRACT A laboratory method was developed to provide an estimate of the amount of hydrogen chloride (HCl) gas formed during waste incineration. The method involves heating the waste sample to 900 °C in a tube furnace, removing particles from the resulting gases by filtration, collecting HCl gas in a water-filled impinger, and measuring the collected HCl as chloride using ion chromatography. The original goal of this project was to develop and evaluate a method that would allow determining, in the laboratory, the amount of HC1 formed upon full-scale incineration of a given hazardous waste feed material. Although the laboratory equipment and procedures performed as designed, the data show that results are very sensitive to materials of construction of the furnace zone, availability of hydrogen, and probably other factors that are difficult to translate accurately from laboratory to full-scale equipment. In particular, the incomplete and variable conversion of inorganic chlorine compounds during incineratio...

Differentiation between organic and inorganic chlorine by electrothermal vaporization inductively coupled plasma mass spectrometry: application to the determination of polychlorinated biphenyls in waste oils

Inductively coupled plasma mass spectrometry (ICP-MS) can be used as a screening test for chlorinated organic compounds such as polychlorinated biphenyls (PCBs) in oils. An upper limit for the PCB concentration can be deduced form the chlorine concentration. Owing to the contamination of oils with inorganic chlorine, a differentiation between ‘organic’ chlorine (PCB-chlorine) and inorganic chlorine is necessary. Electrothermal vaporization ICP-MS achieves this using a temperature programme having one step at 400 °C, for the vaporization of the PCBs, and a second at 2650 °C, for the vaporization of the inorganic chlorine compounds. The detection limits are between 0.5 and 10 µg of PCB per gram of oil depending on the nature of the oil and the degree of chlorination of the PCB.

Kinetic investigations of reactions between inorganic chlorine compounds and luminol

The kinetics of chemiluminescent reactions between chlorine (acidic chlorine and alkaline hypochlorite solutions), chlorine dioxide and luminol have been investigated using stopped-flow techniques. The time course of light decay could be properly analyzed using first-order kinetics. The light emission during the analysis of chlorine solutions continued for a considerably longer period of time than during analysis of chlorine dioxide. Acidic chlorine solutions containing extra chloride produced two different luminescent profiles. The results have been interpreted as indicating that the active species in chlorine solutions which react with luminol are HClO and Cl 2(aq).

The determination of inorganic chlorine compounds by chemiluminescence reactions

A method is described for the determination of chlorine, chlorine dioxide and hypochlorite in aqueous solutions, involving measurement of the chemiluminescence produced during alkaline oxidation of luminol in the presence of hydrogen peroxide. Two different analytical procedures are employed, one based on a pulse technique and the other on continuous flow. Micromolar or submicromolar quantities can be detected.

The vertical distribution of soluble gases in the troposphere

The thermodynamic properties of several water‐soluble gases are reviewed to determine the likely effect of the atmospheric water cycle on their vertical profiles. We find that gaseous HCl, HNO3, and HBr are sufficiently soluble in water to suggest that their vertical profiles in the troposphere have a similar shape to that of water vapor. Thus we predict that HCl, HNO3, and HBr exhibit a steep negative gradient with altitude roughly equal to the altitude gradient of water vapor. Therefore, ground‐based sources of inorganic chlorine, odd nitrogen, and inorganic bromine compounds are not likely to directly affect the stratosphere in the mean. Calculations also show that while SO2 and NH3 are significantly affected by the atmospheric water cycle, their abundances may not decrease with altitude as rapidly as does water vapor.