Principles and Applications of Solid Polymer Electrolyte Reactors for Electrochemical Hydrodehalogenation of Organic Pollutants

NASA Astrophysics Data System (ADS)

Cheng, Hua; Scott, Keith

The ability to re-cycle halogenated liquid wastes, based on electrochemical hydrodehalogenation (EHDH), will provide a significant economic advantage and will reduce the environmental burden in a number of processes. The use of a solid polymer electrolyte (SPE) reactor is very attractive for this purpose. Principles and features of electrochemical HDH technology and SPE EHDH reactors are described. The SPE reactor enables selective dehalogenation of halogenated organic compounds in both aqueous and non-aqueous media with high current efficiency and low energy consumption. The influence of operating conditions, including cathode material, current density, reactant concentration and temperature on the HDH process and its stability are examined.

Recovery of fissile materials from nuclear wastes

DOEpatents

Forsberg, Charles W.

1999-01-01

A process for recovering fissile materials such as uranium, and plutonium, and rare earth elements, from complex waste feed material, and converting the remaining wastes into a waste glass suitable for storage or disposal. The waste feed is mixed with a dissolution glass formed of lead oxide and boron oxide resulting in oxidation, dehalogenation, and dissolution of metal oxides. Carbon is added to remove lead oxide, and a boron oxide fusion melt is produced. The fusion melt is essentially devoid of organic materials and halogens, and is easily and rapidly dissolved in nitric acid. After dissolution, uranium, plutonium and rare earth elements are separated from the acid and recovered by processes such as PUREX or ion exchange. The remaining acid waste stream is vitrified to produce a waste glass suitable for storage or disposal. Potential waste feed materials include plutonium scrap and residue, miscellaneous spent nuclear fuel, and uranium fissile wastes. The initial feed materials may contain mixtures of metals, ceramics, amorphous solids, halides, organic material and other carbon-containing material.

Pyrolysis and dehalogenation of plastics from waste electrical and electronic equipment (WEEE): a review.

PubMed

Yang, Xiaoning; Sun, Lushi; Xiang, Jun; Hu, Song; Su, Sheng

2013-02-01

Plastics from waste electrical and electronic equipment (WEEE) have been an important environmental problem because these plastics commonly contain toxic halogenated flame retardants which may cause serious environmental pollution, especially the formation of carcinogenic substances polybrominated dibenzo dioxins/furans (PBDD/Fs), during treat process of these plastics. Pyrolysis has been proposed as a viable processing route for recycling the organic compounds in WEEE plastics into fuels and chemical feedstock. However, dehalogenation procedures are also necessary during treat process, because the oils collected in single pyrolysis process may contain numerous halogenated organic compounds, which would detrimentally impact the reuse of these pyrolysis oils. Currently, dehalogenation has become a significant topic in recycling of WEEE plastics by pyrolysis. In order to fulfill the better resource utilization of the WEEE plastics, the compositions, characteristics and dehalogenation methods during the pyrolysis recycling process of WEEE plastics were reviewed in this paper. Dehalogenation and the decomposition or pyrolysis of WEEE plastics can be carried out simultaneously or successively. It could be 'dehalogenating prior to pyrolysing plastics', 'performing dehalogenation and pyrolysis at the same time' or 'pyrolysing plastics first then upgrading pyrolysis oils'. The first strategy essentially is the two-stage pyrolysis with the release of halogen hydrides at low pyrolysis temperature region which is separate from the decomposition of polymer matrixes, thus obtaining halogenated free oil products. The second strategy is the most common method. Zeolite or other type of catalyst can be used in the pyrolysis process for removing organohalogens. The third strategy separate pyrolysis and dehalogenation of WEEE plastics, which can, to some degree, avoid the problem of oil value decline due to the use of catalyst, but obviously, this strategy may increase the cost of whole recycling process. Copyright © 2012 Elsevier Ltd. All rights reserved.

Pilot-scale incineration of wastes with high content of chlorinated and non-halogenated organophosphorus flame retardants used as alternatives for PBDEs.

PubMed

Matsukami, Hidenori; Kose, Tomohiro; Watanabe, Mafumi; Takigami, Hidetaka

2014-09-15

Chlorinated and non-halogenated organophosphorus flame retardants (OPFRs) including tris(2-chloroisopropyl) phosphate (TCIPP), diethylene glycol bis(di(2-chloroisopropyl) phosphate) (DEG-BDCIPP), triphenyl phosphate (TPHP), and bisphenol A bis(diphenyl phosphate) (BPA-BDPP) have been used increasingly as alternatives to polybrominated diphenyl ethers and other brominated flame retardants. For this study, five batches of incineration experiments of wastes containing approximately 1% of TCIPP, DEG-BDCIPP, TPHP, and BPA-BDPP were conducted using a pilot-scale incinerator. Destruction and emission behaviors of OPFRs were investigated along with the effects on behaviors of unintentional persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), and pentachlorophenol (PCP). Incineration conditions were chosen according to current regulations for waste incinerators in Japan and UNEP. The OPFRs in the input materials were mainly destroyed in the primary combustion with destruction efficiencies greater than 99.999%. Concentrations of the OPFRs in the exhaust gases and ash were, respectively, <0.01-0.048 μg m(-3) and <0.5-68 μg kg(-1). Almost all of the total phosphorus in the input materials was partitioned into the ash, but less into final exit gases, indicating negligible emissions of volatile phosphorus compounds during incineration. Inputs of chlorinated OPFRs did not affect the formation markedly. Destruction and emission behaviors of unintentional POPs were investigated. Emissions of such POPs in exhaust gases and the ash were lower than the Japanese and international standards. Results show that even in wastes with high contents of chlorinated and non-halogenated OPFRs, waste incineration by the current regulations for the waste incinerators can control environmental emissions of OPFRs and unintentional POPs. Incineration is regarded as a best available technology (BAT) for waste management systems. Copyright © 2014 Elsevier B.V. All rights reserved.

Catalytic wet-oxidation of a mixed liquid waste: COD and AOX abatement.

PubMed

Goi, D; de Leitenburg, C; Trovarelli, A; Dolcetti, G

2004-12-01

A series of catalytic wet oxidation (CWO) reactions, at temperatures of 430-500 K and in a batch bench-top pressure vessel were carried out utilizing a strong wastewater composed of landfill leachate and heavily organic halogen polluted industrial wastewater. A CeO2-SiO2 mixed oxide catalyst with large surface area to assure optimal oxidation performance was prepared. The catalytic process was examined during batch reactions controlling Chemical Oxygen Demand (COD) and Adsorbable Organic Halogen (AOX) parameters, resulting AOX abatement to achieve better effect. Color and pH were also controlled during batch tests. A simple first order-two stage reaction behavior was supposed and verified with the considered parameters. Finally an OUR test was carried out to evaluate biodegradability changes of wastewater as a result of the catalytic reaction.

Process for removal of ammonia and acid gases from contaminated waters

DOEpatents

King, C. Judson; MacKenzie, Patricia D.

1985-01-01

Contaminating basic gases, i.e., ammonia, and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with steam, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

Process for removal of ammonia and acid gases from contaminated waters

DOEpatents

King, C.J.; Mackenzie, P.D.

1982-09-03

Contaminating basic gases, i.e., ammonia and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with stream, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

Mechanochemical pre-treatment for viable recycling of plastic waste containing haloorganics.

PubMed

Cagnetta, Giovanni; Zhang, Kunlun; Zhang, Qiwu; Huang, Jun; Yu, Gang

2018-05-01

Chemical recycling technologies are the most promising for a waste-to-energy/material recovery of plastic waste. However, 30% of such waste cannot be treated in this way due to the presence of halogenated organic compounds, which are often utilized as flame retardants. In fact, high quantities of hydrogen halides and dioxin would form. In order to enabling such huge amount of plastic waste as viable feedstock for recycling, an investigation on mechanochemical pre-treatment by high energy ball milling is carried out on polypropylene containing decabromodiphenyl ether. Results demonstrate that co-milling with zero valent iron and quartz sand ensures complete debromination and mineralization of the flame retardant. Furthermore, a comparative experiment demonstrates that the mechanochemical debromination kinetics is roughly proportional to the polymer-to-haloorganics mass ratio. Copyright © 2018 Elsevier Ltd. All rights reserved.

40 CFR 372.3 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., roasters, and foundry furnaces). (8) Titanium dioxide chloride process oxidation reactors. (9) Methane... sulfur values from spent sulfuric acid. (12) Halogen acid furnaces (HAFs) for the production of acid from halogenated hazardous waste generated by chemical production facilities where the furnace is located on the...

40 CFR 372.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., roasters, and foundry furnaces). (8) Titanium dioxide chloride process oxidation reactors. (9) Methane... sulfur values from spent sulfuric acid. (12) Halogen acid furnaces (HAFs) for the production of acid from halogenated hazardous waste generated by chemical production facilities where the furnace is located on the...

40 CFR 372.3 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... (9) Methane reforming furnaces. (10) Pulping liquor recovery furnaces. (11) Combustion devices used... production of acid from halogenated hazardous waste generated by chemical production facilities where the furnace is located on the site of a chemical production facility, the acid product has a halogen acid...

40 CFR 265.341 - Waste analysis.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Waste analysis. 265.341 Section 265... FACILITIES Incinerators § 265.341 Waste analysis. In addition to the waste analyses required by § 265.13, the... minimum, the analysis must determine: (a) Heating value of the waste; (b) Halogen content and sulfur...

40 CFR 265.341 - Waste analysis.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Waste analysis. 265.341 Section 265... FACILITIES Incinerators § 265.341 Waste analysis. In addition to the waste analyses required by § 265.13, the... minimum, the analysis must determine: (a) Heating value of the waste; (b) Halogen content and sulfur...

Method for halogenating or radiohalogenating a chemical compound

DOEpatents

Kabalka, George W.

2006-05-09

A method for obtaining a halogenated organic compound, whereby an organotrifluoroborate compound is reacted with a halide ion in the presence of an oxidizing agent to produce the corresponding halogenated organic compound. The method may be used for producing radiohalogenated organic compounds.

Catalytic destruction of groundwater contaminants in reactive extraction wells

DOEpatents

McNab, Jr., Walt W.; Reinhard, Martin

2002-01-01

A system for remediating groundwater contaminated with halogenated solvents, certain metals and other inorganic species based on catalytic reduction reactions within reactive well bores. The groundwater treatment uses dissolved hydrogen as a reducing agent in the presence of a metal catalyst, such a palladium, to reduce halogenated solvents (as well as other substituted organic compounds) to harmless species (e.g., ethane or methane) and immobilize certain metals to low valence states. The reactive wells function by removing water from a contaminated water-bearing zone, treating contaminants with a well bore using catalytic reduction, and then reinjecting the treated effluent into an adjacent water-bearing zone. This system offers the advantages of a compact design with a minimal surface footprint (surface facilities) and the destruction of a broad suite of contaminants without generating secondary waste streams.

Organic Halogen and Related Trace Gases in the Tropical Atmosphere: Results from Recent Airborne Campaigns Over the Pacific

NASA Astrophysics Data System (ADS)

Atlas, E. L.; Navarro, M. A.; Donets, V.; Schauffler, S.; Lueb, R.; Hendershot, R.; Gabbard, S.; Hornbrook, R. S.; Apel, E. C.; Riemer, D. D.; Pan, L.; Salawitch, R. J.; Nicely, J. M.; Montzka, S. A.; Miller, B.; Moore, F. L.; Elkins, J. W.; Hintsa, E. J.; Campos, T. L.; Quack, B.; Zhu, X.; Pope, L.

2014-12-01

Organic halogen gases, especially containing bromine and iodine, play a significant role as precursors to active halogen chemistry and ozone catalytic loss. Much of the reactive organic halogen originates from biological processes in the surface ocean, which can be quite variable by season and location. The tropics and coastal margins are potentially important sources that are being examined. The recent coordinated CONTRAST/ATTREX/CAST missions were conducted in the Western Tropical Pacific, a region that is a major transport pathway for tropospheric air entering the stratosphere. One of the goals of the missions was to identify sources, distributions, and transport of organic halogens from the ocean surface into the tropical lower stratosphere. The missions were conducted during the NH winter season, Jan-Feb, 2014. In this presentation, we will discuss the distributions and variability of organic halogen gases in the study region and will examine the input of organic halogen species into the Tropical Tropopause Layer (TTL). Comparison with other tracers, such as methyl nitrate and NMHC, will help identify source regions for these gases. We will focus on the measurements obtained in the CONTRAST and ATTREX missions with data from in-situ GC/MS measurements and whole air samples collected on the NSF GV and NASA Global Hawk aircraft. Comparisons with other recent airborne campaigns, such as HIPPO and TC4, and with several ship-based studies will provide an additional context for evaluating the variability of organic halogen species in the tropical atmosphere and their role in transporting reactive halogen compounds into the UT/LS.

40 CFR 721.8700 - Halogenated alkyl pyridine.

Code of Federal Regulations, 2011 CFR

2011-07-01

... tertiary waste treatment will occur, or treatment in a lined, self-contained solar evaporation pond where..., secondary, and tertiary waste treatment will occur, or treatment in a lined, self-contained solar...

40 CFR 721.8700 - Halogenated alkyl pyridine.

Code of Federal Regulations, 2010 CFR

2010-07-01

... tertiary waste treatment will occur, or treatment in a lined, self-contained solar evaporation pond where..., secondary, and tertiary waste treatment will occur, or treatment in a lined, self-contained solar...

Likelihood of atom-atom contacts in crystal structures of halogenated organic compounds.

PubMed

Jelsch, Christian; Soudani, Sarra; Ben Nasr, Cherif

2015-05-01

The likelihood of occurrence of intermolecular contacts in crystals of halogenated organic compounds has been analysed statistically using tools based on the Hirshfeld surface. Several families of small halogenated molecules (containing organic F, Cl, Br or I atoms) were analysed, based on chemical composition and aromatic or aliphatic character. The behaviour of crystal contacts was also probed for molecules containing O or N. So-called halogen bonding (a halogen making short interactions with O or N, or a π interaction with C) is generally disfavoured, except when H is scarce on the molecular surface. Similarly, halogen⋯halogen contacts are more rare than expected, except for molecules that are poor in H. In general, the H atom is found to be the preferred partner of organic halogen atoms in crystal structures. On the other hand, C⋯C interactions in parallel π-stacking have a high propensity to occur in halogenated aromatic molecules. The behaviour of the four different halogen species (F, Cl, Br, I) is compared in several chemical composition contexts. The analysis tool can be refined by distinguishing several types for a given chemical species, such as H atoms bound to O or C. Such distinction shows, for instance, that C-H⋯Cl and O-H⋯O are the preferred interactions in compounds containing both O and Cl.

Is halogen content the most important factor in the removal of halogenated trace organics by MBR treatment?

PubMed

Hai, Faisal I; Tadkaew, Nichanan; McDonald, James A; Khan, Stuart J; Nghiem, Long D

2011-05-01

This study investigated the relationship between physicochemical properties (namely halogen content and hydrophobicity) of halogenated trace organics and their removal efficiencies by a laboratory scale membrane bioreactor (MBR) under stable operating conditions. The reported results demonstrated a combined effect of halogen content and hydrophobicity on the removal. Compounds with high halogen content (>0.3) were well removed (>85%) when they possessed high hydrophobicity (Log D>3.2), while those with lower Log D values were also well removed if they had low halogen content (<0.1). General indices such as the BIOWIN index (which is based on only biodegradation) or a more specific index such as the halogen content (which captures a chemical aspect) appeared insufficient to predict the removal efficiency of halogenated compounds in MBR. Experimental data confirmed that the ratio of halogen content and Log D, which incorporates two important physico-chemical properties, is comparatively more suitable. Copyright © 2011 Elsevier Ltd. All rights reserved.

Halogen Chemistry in the CMAQ Model

EPA Science Inventory

Halogens (iodine and bromine) emitted from oceans alter atmospheric chemistry and influence atmospheric ozone mixing ratio. We previously incorporated a representation of detailed halogen chemistry and emissions of organic and inorganic halogen species into the hemispheric Commun...

Aerosol-halogen interaction: Change of physico-chemical properties of SOA by naturally released halogen species

NASA Astrophysics Data System (ADS)

Ofner, J.; Balzer, N.; Buxmann, J.; Grothe, H.; Krüger, H.; Platt, U.; Schmitt-Kopplin, P.; Zetzsch, C.

2011-12-01

Reactive halogen species are released by various sources like photo-activated sea-salt aerosol or salt pans and salt lakes. These heterogeneous release mechanisms have been overlooked so far, although their potential of interaction with organic aerosols like Secondary Organic Aerosol (SOA), Biomass Burning Organic Aerosol (BBOA) or Atmospheric Humic LIke Substances (HULIS) is completely unknown. Such reactions can constitute sources of gaseous organo-halogen compounds or halogenated organic particles in the atmospheric boundary layer. To study the interaction of organic aerosols with reactive halogen species (RHS), SOA was produced from α-pinene, catechol and guaiacol using an aerosol smog-chamber. The model SOAs were characterized in detail using a variety of physico-chemical methods (Ofner et al., 2011). Those aerosols were exposed to molecular halogens in the presence of UV/VIS irradiation and to halogens, released from simulated natural halogen sources like salt pans, in order to study the complex aerosol-halogen interaction. The heterogeneous reaction of RHS with those model aerosols leads to different gaseous species like CO2, CO and small reactive/toxic molecules like phosgene (COCl2). Hydrogen containing groups on the aerosol particles are destroyed to form HCl or HBr, and a significant formation of C-Br bonds could be verified in the particle phase. Carbonyl containing functional groups of the aerosol are strongly affected by the halogenation process. While changes of functional groups and gaseous species were visible using FTIR spectroscopy, optical properties were studied using Diffuse Reflectance UV/VIS spectroscopy. Overall, the optical properties of the processed organic aerosols are significantly changed. While chlorine causes a "bleaching" of the aerosol particles, bromine shifts the maximum of UV/VIS absorption to the red end of the UV/VIS spectrum. Further physico-chemical changes were recognized according to the aerosol size-distributions or the averaged carbon oxidation state (OSc). The heterogeneous reaction of SOA with molecular halogens released from the simulated salt-pan at different simulated environmental conditions leads to changes of several physico-chemical features of the aerosol. However, the halogen release mechanisms are also affected by the presence of organic aerosols. One order of magnitude less BrO was detected by an active Differential Optical Absorption Spectroscopy (DOAS) instrument in the presence of SOA compared to experiments without SOA. This work was supported by the German Research Foundation within the HALOPROC project. Ofner, J., Krüger, H.-U., Grothe, H., Schmitt-Kopplin, P., Whitmore, K., and Zetzsch, C. (2011), Atmos. Chem. Phys., 11, 1-15.

Geobacter strains that use alternate organic compounds, methods of making, and methods of use thereof

DOEpatents

Lovley, Derek R.; Summers, Zarath Morgan; Haveman, Shelley Annette; Izallalen, Mounir

2016-03-01

In preferred embodiments, the present invention provides new isolated strains of a Geobacter species that are capable of using a carbon source that is selected from C.sub.3 to C.sub.12 organic compounds selected from pyruvate or metabolic precursors of pyruvate as an electron donor in metabolism and in subsequent energy production. The wild type strain of the microorganisms has been shown to be unable to use these C.sub.3 to C.sub.12 organic compounds as electron donors. The inventive strains of microorganisms are useful for improving bioremediation applications, including in situ bioremediation (including uranium bioremediation and halogenated solvent bioremediation), microbial fuel cells, power generation from small and large-scale waste facilities (e.g., biomass waste from dairy, agriculture, food processing, brewery, or vintner industries, etc.) using microbial fuel cells, and other applications of microbial fuel cells, including, but not limited to, improved electrical power supplies for environmental sensors, electronic devices, and electric vehicles.

Process for removal of hydrogen halides or halogens from incinerator gas

DOEpatents

Huang, Hann S.; Sather, Norman F.

1988-01-01

A process for reducing the amount of halogens and halogen acids in high temperature combustion gases and through their removal, the formation of halogenated organics at lower temperatures, with the reduction being carried out electrochemically by contacting the combustion gas with the negative electrode of an electrochemical cell and with the halogen and/or halogen acid being recovered at the positive electrode.

Process for removal of hydrogen halides or halogens from incinerator gas

DOEpatents

Huang, H.S.; Sather, N.F.

1987-08-21

A process for reducing the amount of halogens and halogen acids in high temperature combustion gas and through their removal, the formation of halogenated organics at lower temperatures, with the reduction being carried out electrochemically by contacting the combustion gas with the negative electrode of an electrochemical cell and with the halogen and/or halogen acid being recovered at the positive electrode.

Spatial distribution and implications to sources of halogenated flame retardants in riverine sediments of Taizhou, an intense e-waste recycling area in eastern China.

PubMed

Zhou, Shanshan; Fu, Jie; He, Huan; Fu, Jianjie; Tang, Qiaozhi; Dong, Minfeng; Pan, Yongqiang; Li, An; Liu, Weiping; Zhang, Limin

2017-10-01

Concentrations and spatial distribution pattern of organohalogen flame retardants were investigated in the riverine surface sediments from Taizhou, an intensive e-waste recycling region in China. The analytes were syn- and anti- Dechlorane Plus (DP), Dechloranes 602, 603, and 604, a DP monoadduct, two dechlorinated DPs and 8 congeners of polybrominated diphenyl ethers (PBDEs). The concentrations of Σ 8 PBDEs, ΣDP, ΣDec600s, and ΣDP-degradates ranged from <100 to 172,000, 100 to 55,000, not detectable (nd) to 1600, and nd to 2800 pg/g dry weight, respectively. BDE-209 and DP, both have been manufactured in China, had similar spatial distribution patterns in the study area, featured by distinctly recognizable hotspots some of which are in proximity to known e-waste dumping or metal recycling facilities. Such patterns were largely shared by Dec602 and dechlorinated DP, although their concentration levels were much lower. These major flame retardants significantly correlate with each other, and cluster together in the loading plot of principle component analysis. In contrast, most non-deca PBDE congeners do not correlate with DPs. Dec604 stood out having distinctly different spatial distribution pattern, which could be linked to historical use of mirex. Organic matter content of the sediment was not the dominant factor in determining the spatial pattern of pollution by halogenated flame retardants in the rivers of this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Temporal dynamics of halogenated organic compounds in Marcellus Shale flowback.

PubMed

Luek, Jenna L; Harir, Mourad; Schmitt-Kopplin, Philippe; Mouser, Paula J; Gonsior, Michael

2018-06-01

The chemistry of hydraulic fracturing fluids and wastewaters is complex and is known to vary by operator, geologic formation, and fluid age. A time series of hydraulic fracturing fluids, flowback fluids, and produced waters was collected from two adjacent Marcellus Shale gas wells for organic chemical composition analyses using ultrahigh resolution mass spectrometry. Hierarchical clustering was used to compare and extract ions related to different fluid ages and many halogenated organic molecular ions were identified in flowback fluids and early produced waters based on exact mass. Iodinated organic compounds were the dominant halogen class in these clusters and were nearly undetectable in hydraulic fracturing fluid prior to injection. The iodinated ions increased in flowback and remained elevated after ten months of well production. We suggest that these trends are mainly driven by dissolved organic matter reacting with reactive halogen species formed abiotically through oxidizing chemical additives applied to the well and biotically via iodide-oxidizing bacteria. Understanding the implications of these identified halogenated organic compounds will require future investigation in to their structures and environmental fate. Copyright © 2018 Elsevier Ltd. All rights reserved.

Status of electronic waste recycling techniques: a review.

PubMed

Abdelbasir, Sabah M; Hassan, Saad S M; Kamel, Ayman H; El-Nasr, Rania Seif

2018-05-08

The increasing use of electrical and electronic equipment leads to a huge generation of electronic waste (e-waste). It is the fastest growing waste stream in the world. Almost all electrical and electronic equipment contain printed circuit boards as an essential part. Improper handling of these electronic wastes could bring serious risk to human health and the environment. On the other hand, proper handling of this waste requires a sound management strategy for awareness, collection, recycling, and reuse. Nowadays, the effective recycling of this type of waste has been considered as a main challenge for any society. Printed circuit boards (PCBs), which are the base of many electronic industries, are rich in valuable heavy metals and toxic halogenated organic substances. In this review, the composition of different PCBs and their harmful effects are discussed. Various techniques in common use for recycling the most important metals from the metallic fractions of e-waste are illustrated. The recovery of metals from e-waste material after physical separation through pyrometallurgical, hydrometallurgical, or biohydrometallurgical routes is also discussed, along with alternative uses of non-metallic fraction. The data are explained and compared with the current e-waste management efforts done in Egypt. Future perspectives and challenges facing Egypt for proper e-waste recycling are also discussed.

Enzymatic Halogenation and Dehalogenation Reactions: Pervasive and Mechanistically Diverse.

PubMed

Agarwal, Vinayak; Miles, Zachary D; Winter, Jaclyn M; Eustáquio, Alessandra S; El Gamal, Abrahim A; Moore, Bradley S

2017-04-26

Naturally produced halogenated compounds are ubiquitous across all domains of life where they perform a multitude of biological functions and adopt a diversity of chemical structures. Accordingly, a diverse collection of enzyme catalysts to install and remove halogens from organic scaffolds has evolved in nature. Accounting for the different chemical properties of the four halogen atoms (fluorine, chlorine, bromine, and iodine) and the diversity and chemical reactivity of their organic substrates, enzymes performing biosynthetic and degradative halogenation chemistry utilize numerous mechanistic strategies involving oxidation, reduction, and substitution. Biosynthetic halogenation reactions range from simple aromatic substitutions to stereoselective C-H functionalizations on remote carbon centers and can initiate the formation of simple to complex ring structures. Dehalogenating enzymes, on the other hand, are best known for removing halogen atoms from man-made organohalogens, yet also function naturally, albeit rarely, in metabolic pathways. This review details the scope and mechanism of nature's halogenation and dehalogenation enzymatic strategies, highlights gaps in our understanding, and posits where new advances in the field might arise in the near future.

Anaerobic degradation of polychlorinated biphenyls (PCBs) and polychlorinated biphenyls ethers (PBDEs), and microbial community dynamics of electronic waste-contaminated soil.

PubMed

Song, Mengke; Luo, Chunling; Li, Fangbai; Jiang, Longfei; Wang, Yan; Zhang, Dayi; Zhang, Gan

2015-01-01

Environmental contamination caused by electronic waste (e-waste) recycling is attracting increasing attention worldwide because of the threats posed to ecosystems and human safety. In the present study, we investigated the feasibility of in situ bioremediation of e-waste-contaminated soils. We found that, in the presence of lactate as an electron donor, higher halogenated congeners were converted to lower congeners via anaerobic halorespiration using ferrous ions in contaminated soil. The 16S rRNA gene sequences of terminal restriction fragments indicated that the three dominant strains were closely related to known dissimilatory iron-reducing bacteria (DIRB) and those able to perform dehalogenation upon respiration. The functional species performed the activities of ferrous oxidation to ferric ions and further ferrous reduction for dehalogenation. The present study links iron cycling to degradation of halogenated materials in natural e-waste-contaminated soil, and highlights the synergistic roles of soil bacteria and ferrous/ferric ion cycling in the dehalogenation of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs). Copyright © 2014 Elsevier B.V. All rights reserved.

Electrical and electronic plastics waste co-combustion with municipal solid waste for energy recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vehlow, J.; Mark, F.E.

1997-12-01

The recovery or disposal of end-of-life electrical and electronic (E+E) equipment is receiving considerable attention from industry organisations such as APME in order to supply factual information which can be used in the development of a clear industry strategy. It is hoped that such information will persuade EU member states to define the best management practices for this waste stream. One of the difficulties regarding the recovery or disposal of E+E waste is a lack of data regarding its behaviour when incinerated. This lack of data has led to unfounded conclusions by sonic parties that plastic wastes contain harmful halogenatedmore » species which are difficult to treat and remove, and when incinerated contribute to the emission of halogenated species and are responsible for the major portion of emissions. APME has a comprehensive testing program investigating the impact of plastics on municipal solid waste (MSW) incineration. APME`s previous work has demonstrated the positive, beneficial effects of mixed waste plastics in the MSW energy recovery process as well as studying halogen behaviour during the combustion of packaging plastics waste and construction foam from the building industry. The current study was designed to evaluate the incineration of MSW containing typical levels of electrical and electronic (E+E) plastic waste, as well as MSW containing E+E waste in amounts up to 12%.« less

Plant selective uptake of halogenated flame retardants at an e-waste recycling site in southern China.

PubMed

Wang, Shaorui; Wang, Yan; Luo, Chunling; Li, Jun; Yin, Hua; Zhang, Gan

2016-07-01

The concentrations and homolog patterns of halogenated flame retardants (HFRs) in vegetables grown at an e-waste contaminated site were investigated. Polybrominated diphenyl ethers (PBDEs) were the dominant HFRs in vegetable tissues, with concentrations ranging from 10.3 to 164 ng g(-1) and 1.16-107 ng g(-1) in shoots and roots, respectively, followed by novel brominated flame retardants (NBFRs) and dechlorane plus (DPs). This is an indication that PBDE contamination in vegetables grown around e-waste recycling sites may pose a risk to the local terrestrial ecosystem and residents. In addition, this is the first report on the concentrations and compositions of NBFRs in vegetables around e-waste recycling sites. The HFRs concentrations in vegetables varied greatly with the vegetable species, with the highest concentrations observed in Brassica oleracea var. capitata. Root concentration factors (RCF) decreased with increasing log Kow of HFRs, which indicated that the uptake of HFRs was controlled mainly by log Kow. Dissimilar HFRs profiles in shoots and roots suggested that the uptake and translocation of HFRs by plants were selective, with lower halogenated congeners prone to accumulation in vegetable tissues. Positive relationships between PBDEs and their substitutes were observed in vegetable tissues, suggesting that the replacement of PBDEs by NBFRs has not resulted in an obvious transition in plants within the study area. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation of halogenated aliphatic compounds by Xanthobacter autotrophicus GJ10.

PubMed Central

Janssen, D B; Scheper, A; Dijkhuizen, L; Witholt, B

1985-01-01

A bacterium that is able to utilize a number of halogenated short-chain hydrocarbons and halogenated carboxylic acids as sole carbon source for growth was identified as a strain of Xanthobacter autotrophicus. The organism constitutively produces two different dehalogenases. One enzyme is specific for halogenated alkanes, whereas the other, which is more heat stable and has a higher pH optimum, is specific for halogenated carboxylic acids. Haloalkanes were hydrolyzed in cell extracts to produce alcohols and halide ions, and a route for the metabolism of 1,2-dichlorethane is proposed. Both dehalogenases show a broad substrate specificity, allowing the degradation of bromine- and chlorine-substituted organic compounds. The results show that X. autotrophicus may play a role in the degradation of organochlorine compounds and that hydrolytic dehalogenases may be involved in the microbial metabolism of short-chain halogenated hydrocarbons in microorganisms. Images PMID:3994371

Competition between Halogen, Hydrogen and Dihydrogen Bonding in Brominated Carboranes.

PubMed

Fanfrlík, Jindřich; Holub, Josef; Růžičková, Zdeňka; Řezáč, Jan; Lane, Paul D; Wann, Derek A; Hnyk, Drahomír; Růžička, Aleš; Hobza, Pavel

2016-11-04

Halogen bonds are a subset of noncovalent interactions with rapidly expanding applications in materials and medicinal chemistry. While halogen bonding is well known in organic compounds, it is new in the field of boron cluster chemistry. We have synthesized and crystallized carboranes containing Br atoms in two different positions, namely, bound to C- and B-vertices. The Br atoms bound to the C-vertices have been found to form halogen bonds in the crystal structures. In contrast, Br atoms bound to B-vertices formed hydrogen bonds. Quantum chemical calculations have revealed that halogen bonding in carboranes can be much stronger than in organic architectures. These findings open new possibilities for applications of carboranes, both in materials and medicinal chemistry. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanochemical synthesis of small organic molecules

PubMed Central

Achar, Tapas Kumar; Bose, Anima

2017-01-01

With the growing interest in renewable energy and global warming, it is important to minimize the usage of hazardous chemicals in both academic and industrial research, elimination of waste, and possibly recycle them to obtain better results in greener fashion. The studies under the area of mechanochemistry which cover the grinding chemistry to ball milling, sonication, etc. are certainly of interest to the researchers working on the development of green methodologies. In this review, a collection of examples on recent developments in organic bond formation reactions like carbon–carbon (C–C), carbon–nitrogen (C–N), carbon–oxygen (C–O), carbon–halogen (C–X), etc. is documented. Mechanochemical syntheses of heterocyclic rings, multicomponent reactions and organometallic molecules including their catalytic applications are also highlighted. PMID:29062410

Method and apparatus for vapor detection

NASA Technical Reports Server (NTRS)

Lerner, Melvin (Inventor); Hood, Lyal V. (Inventor); Rommel, Marjorie A. (Inventor); Pettitt, Bruce C. (Inventor); Erikson, Charles M. (Inventor)

1980-01-01

The method disclosed herein may be practiced by passing the vapors to be sampled along a path with halogen vapor, preferably chlorine vapor, heating the mixed vapors to halogenate those of the sampled vapors subject to halogenation, removing unreacted halogen vapor, and then sensing the vapors for organic halogenated compounds. The apparatus disclosed herein comprises means for flowing the vapors, both sample and halogen vapors, into a common path, means for heating the mixed vapors to effect the halogenation reaction, means for removing unreacted halogen vapor, and a sensing device for sensing halogenated compounds. By such a method and means, the vapors of low molecular weight hydrocarbons, ketones and alcohols, when present, such as methane, ethane, acetone, ethanol, and the like are converted, at least in part, to halogenated compounds, then the excess halogen removed or trapped, and the resultant vapors of the halogenated compounds sensed or detected. The system is highly sensitive. For example, acetone in a concentration of 30 parts per billion (volume) is readily detected.

Photochemically and Thermally Driven Full-Color Reflection in a Self-Organized Helical Superstructure Enabled by a Halogen-Bonded Chiral Molecular Switch.

PubMed

Wang, Hao; Bisoyi, Hari Krishna; Wang, Ling; Urbas, Augustine M; Bunning, Timothy J; Li, Quan

2018-02-05

Supramolecular approaches toward the fabrication of functional materials and systems have been an enabling endeavor. Recently, halogen bonding has been harnessed as a promising supramolecular tool. Herein we report the synthesis and characterization of a novel halogen-bonded light-driven axially chiral molecular switch. The photoactive halogen-bonded chiral switch is able to induce a self-organized, tunable helical superstructure, that is, cholesteric liquid crystal (CLC), when doped into an achiral liquid crystal (LC) host. The halogen-bonded switch as a chiral dopant has a high helical twisting power (HTP) and shows a large change of its HTP upon photoisomerization. This light-driven dynamic modulation enables reversible selective reflection color tuning across the entire visible spectrum. The chiral switch also displays a temperature-dependent HTP change that enables thermally driven red, green, and blue (RGB) reflection colors in the self-organized helical superstructure. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Volatile Halogenated Organic Compounds Released to Seawater from Temperate Marine Macroalgae

NASA Astrophysics Data System (ADS)

Gschwend, Philip M.; Macfarlane, John K.; Newman, Kathleen A.

1985-03-01

Volatile halogenated organic compounds synthesized by various industrial processes are troublesome pollutants because they are persistent in terrestrial ecosystems and because they may be present in sufficient quantities to alter the natural atmospheric cycles of the halogens. Certain of these compounds, including polybromomethanes and several previously unobserved alkyl monohalides and dihalides, appear to be natural products of the marine environment. A variety of temperate marine macroalgae (the brown algae Ascophyllum nodosum and Fucus vesiculosis, the green algae Enteromorpha linza and Ulva lacta, and the red alga Gigartina stellata) not only contain volatile halogenated organic compounds but also release them to seawater at rates of nanograms to micrograms of each compound per gram of dry algae per day. The macroalgae may be an important source of bromine-containing material released to the atmosphere.

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

DOEpatents

Golden, Jeffry

2007-02-13

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

DOEpatents

Mincher, Bruce J.; Curry, Randy Dale; Clevenger, Thomas E.; Golden, Jeffry

2003-05-27

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

DOEpatents

Mincher, Bruce J.; Curry, Randy Dale; Clevenger, Thomas E.; Golden, Jeffry

2000-01-01

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacting a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Reversible capture and release of Cl 2 and Br 2 with a redox-active metal–organic framework

DOE PAGES

Tulchinsky, Yuri; Hendon, Christopher H.; Lomachenko, Kirill A.; ...

2017-03-28

Extreme toxicity, corrosiveness, and volatility pose serious challenges for the safe storage and transportation of elemental chlorine and bromine, which play critical roles in the chemical industry. Solid materials capable of forming stable nonvolatile compounds upon reaction with elemental halogens may partially mitigate these challenges by allowing safe halogen release on demand. Here we demonstrate that elemental halogens quantitatively oxidize coordinatively unsaturated Co(II) ions in a robust azolate metal-organic framework (MOF) to produce stable and safe-to-handle Co(III) materials featuring terminal Co(III)-halogen bonds. Thermal treatment of the oxidized MOF causes homolytic cleavage of the Co(III)-halogen bonds, reduction to Co(II), and concomitantmore » release of elemental halogens. The reversible chemical storage and thermal release of elemental halogens occur with no significant losses of structural integrity, as the parent cobaltous MOF retains its crystallinity and porosity even after three oxidation/reduction cycles. Finally, these results highlight a material operating via redox mechanism that may find utility in the storage and capture of other noxious and corrosive gases.« less

Preliminary evaluation of evaluation of the efficiency of aircraft liquid waste treatment using resolvable sanitizing liquid: a case study in Changchun.

PubMed

Xu, Jianling; Yang, Jiaqi; Zhao, Nan; Sheng, Lianxi; Zhao, Yuanhui; Tang, Zhanhui

2011-12-01

The physical, chemical, and biological indices of aircraft liquid wastes collected from multiple airplanes at Longjia Airport, Changchun, China were measured according to "Integrated Wastewater Discharge Standard," evaluating treatment efficiency of resolvable sanitizing liquid. The results indicate that, after being treated by the resolvable sanitizing liquid, the indices of all first-class pollutants met the requirements of the standard, while among the second-class pollutants, the suspension content, biochemical oxygen demand after 5 days, and chemical oxygen demand as well as the contents of amino nitrogen, total phosphorus, anionic surfactants, total copper, absorbable organic halogen, and phenolic compounds did not reach the discharge standard. Particularly, the level of fecal coliform bacteria in the aircraft liquid wastes can meet the standard specification by adding more than 1 mL/L resolvable sanitizing liquid. The aircraft wastewater treated by resolvable sanitizing liquid cannot be directly discharged back into the environment as well as urban drainage systems.

Halogen dependent symmetry change in two series of wheel cluster organic frameworks built from La18 tertiary building units.

PubMed

Fang, Wei-Hui; Zhang, Lei; Zhang, Jian; Yang, Guo-Yu

2016-01-25

Two series of wheel cluster organic frameworks (WCOFs) built from La18 tertiary building units are hydrothermally made, which show halogen-dependent structural symmetry, and demonstrate different chiral performances.

Iron Mineral Catalyzed C-H Activation As a Potential Pathway for Halogenation Processes

NASA Astrophysics Data System (ADS)

Tubbesing, C.; Schoeler, H. F.; Benzing, K.; Krause, T.; Lippe, S.; Rudloff, M.

2014-12-01

Due to increasing drinking water demand of mankind and an expected climate change the impact of salt lakes and salt deserts will increase within the next decades. Furthermore, a rising sea level influences coastal areas like salt marshes and abets processes which will lead to elevated organohalogen formation. An additional increase of the global warming potential, of particle formation and stratospheric ozone depletion is expected. Understanding these multifaceted processes is essential for mankind to be prepared for these alterations of the atmosphere. For example, Keppler et al. (2000) described the production of volatile halogenated organic compounds via oxidation of organic matter driven by ferric iron. However, the formation of long-chained alkyl halides in salt lakes is yet undisclosed. Despite the relative "inertness" of alkanes a direct halogenation of these compounds might be envisaged. In 2005 Vaillancourt et al. discovered a nonheme iron enzyme which is able to halogenate organic compounds via generating the high valent ferryl cation as reaction center. Based on various publications about C-H activation (Bergman, 2007) we postulate a halogenation process in which an iron containing minerals catalyse the C-H bond cleavage of organic compounds in soils. The generated organic radicals are highly reactive towards halides connected to the iron complex. We suggest that next to diagenetically altered iron containing enzymes, minerals such as oxides, hydroxides and sulfides are involved in abiotic halogenation processes. We applied the amino acid methionine as organic model compound and soluble iron species as reactants. All samples were incubated in aqueous phases containing various NaCl concentrations. As a result various halogenated ethanes and ethenes were identified as reaction products. References Bergman, R. G. (2007) Nature, 446(7134) 391-393 Keppler, F., et al. (2000) Nature, 403(6767) 298-301 Vaillancourt, F. H., et al. (2005) Nature, 436(7054) 1191-1194

Removal of Intermediate Aromatic Halogenated DBPs by Activated Carbon Adsorption: A New Approach to Controlling Halogenated DBPs in Chlorinated Drinking Water.

PubMed

Jiang, Jingyi; Zhang, Xiangru; Zhu, Xiaohu; Li, Yu

2017-03-21

During chlorine disinfection of drinking water, chlorine may react with natural organic matter (NOM) and bromide ion in raw water to generate halogenated disinfection byproducts (DBPs). To mitigate adverse effects from DBP exposure, granular activated carbon (GAC) adsorption has been considered as one of the best available technologies for removing NOM (DBP precursor) in drinking water treatment. Recently, we have found that many aromatic halogenated DBPs form in chlorination, and they act as intermediate DBPs to decompose and form commonly known DBPs including trihalomethanes and haloacetic acids. In this work, we proposed a new approach to controlling drinking water halogenated DBPs by GAC adsorption of intermediate aromatic halogenated DBPs during chlorination, rather than by GAC adsorption of NOM prior to chlorination (i.e., traditional approach). Rapid small-scale column tests were used to simulate GAC adsorption in the new and traditional approaches. Significant reductions of aromatic halogenated DBPs were observed in the effluents with the new approach; the removals of total organic halogen, trihalomethanes, and haloacetic acids by the new approach always exceeded those by the traditional approach; and the effluents with the new approach were considerably less developmentally toxic than those with the traditional approach. Our findings indicate that the new approach is substantially more effective in controlling halogenated DBPs than the traditional approach.

Organic halogenated contaminants in mother-fetus pairs of harbor seals (Phoca vitulina richardii) from Alaska, 2000-2002

USDA-ARS?s Scientific Manuscript database

Environmental stressors may interfere with foraging, survival and reproduction of marine mammals resulting in marine mammal population decline. In this study, organic halogenated pollutants [OHs, including organochlorine pesticides, polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCN...

Efficiency of inductively torch plasma operating at atmospheric pressure on destruction of chlorinated liquid wastes- A path to the treatment of radioactive organic halogen liquid wastes

NASA Astrophysics Data System (ADS)

Kamgang-Youbi, G.; Poizot, K.; Lemont, F.

2012-12-01

The performance of a plasma reactor for the degradation of chlorinated hydrocarbon waste is reported. Chloroform was used as a target for a recently patented destruction process based using an inductive plasma torch. Liquid waste was directly injected axially into the argon plasma with a supplied power of ~4 kW in the presence of oxygen as oxidant and carrier gas. Decomposition was performed at CHCl3 feed rates up to 400 g·h-1 with different oxygen/waste molar ratios, chloroform destruction was obtained with at least 99% efficiency and the energy efficiency reached 100 g·kWh-1. The conversion end products were identified and assayed by online FTIR spectroscopy (CO2, HCl and H2O) and redox titration (Cl2). Considering phosgene as representative of toxic compounds, only very small quantities of toxics were released (< 1 g·h-1) even with high waste feed rates. The experimental results were very close to the equilibrium composition predicted by thermodynamic calculations. At the bottom of the reactor, the chlorinated acids were successfully trapped in a scrubber and transformed into mineral salts, hence, only CO2 and H2O have been found in the final off-gases composition.

40 CFR 63.8000 - What are my general requirements for complying with this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... atoms, and you use a combustion-based control device (excluding a flare) to meet an organic HAP emission... calculating the concentration of each organic compound that contains halogen atoms using the procedures specified in § 63.115(d)(2)(v), multiplying each concentration by the number of halogen atoms in the organic...

40 CFR 63.8000 - What are my general requirements for complying with this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... atoms, and you use a combustion-based control device (excluding a flare) to meet an organic HAP emission... calculating the concentration of each organic compound that contains halogen atoms using the procedures specified in § 63.115(d)(2)(v), multiplying each concentration by the number of halogen atoms in the organic...

40 CFR 63.8000 - What are my general requirements for complying with this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... atoms, and you use a combustion-based control device (excluding a flare) to meet an organic HAP emission... calculating the concentration of each organic compound that contains halogen atoms using the procedures specified in § 63.115(d)(2)(v), multiplying each concentration by the number of halogen atoms in the organic...

40 CFR 63.8000 - What are my general requirements for complying with this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... atoms, and you use a combustion-based control device (excluding a flare) to meet an organic HAP emission... calculating the concentration of each organic compound that contains halogen atoms using the procedures specified in § 63.115(d)(2)(v), multiplying each concentration by the number of halogen atoms in the organic...

40 CFR 63.8000 - What are my general requirements for complying with this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... atoms, and you use a combustion-based control device (excluding a flare) to meet an organic HAP emission... calculating the concentration of each organic compound that contains halogen atoms using the procedures specified in § 63.115(d)(2)(v), multiplying each concentration by the number of halogen atoms in the organic...

Electroreduction of Halogenated Organic Compounds

NASA Astrophysics Data System (ADS)

Rondinini, Sandra; Vertova, Alberto

The electroreductive cleavage of the carbon-halogen bond in halogenated organic compounds has been extensively studied for more than 70 years, since it is prodromal to a large variety of synthetic applications in organic electrochemistry. Over the years the research interest have progressively included the environmental applications, since several organic halocompounds are known to have (or have had) a serious environmental impact because of their (present or past) wide use as cleaning agents, herbicides, cryogenic fluids, reagents (e.g. allyl and vinyl monomers) for large production materials, etc. Recent studies have also demonstrated the wide spread out- and in-door-presence of volatile organic halides, although at low level, in connexion with residential and non-residential (e.g. stores, restaurants and transportation) activities. In this context, the detoxification of emissions to air, water and land by the selective removal of the halogen group represents a valid treatment route, which, although not leading to the complete mineralization of the pollutants, produces less harmful streams to be easily treated by electrochemical or conventional techniques. The electroreduction process is analysed and discussed in terms of electrode material, reaction medium, cell design and operation, and of substrate classification.

Geobacter strains that use alternate organic compounds, methods of making, and methods of use thereof

DOEpatents

Lovley, Derek R; Summers, Zarath Morgan; Haveman, Shelley Annette; Izallalen, Mounir

2013-12-03

In preferred embodiments, the present invention provides new isolated strains of Geobacter species that are capable of using a carbon source that is selected from C.sub.3 to C.sub.12 organic compounds selected from pyruvate or metabolic precursors of pyruvate as an electron donor in metabolism and in subsequent energy production. In other aspects, other preferred embodiments of the present invention include methods of making such strains and methods of using such strains. In general, the wild type strain of the microorganisms has been shown to be unable to use these C.sub.3 to C.sub.12 organic compounds as electron donors in metabolic steps such as the reduction of metallic ions. The inventive strains of microorganisms are useful improving bioremediation applications, including in situ bioremediation (including uranium bioremediation and halogenated solvent bioremediation), microbial fuel cells, power generation from small and large-scale waste facilities (e.g., biomass waste from dairy, agriculture, food processing, brewery, or vintner industries, etc.) using microbial fuel cells, and other applications of microbial fuel cells, including, but not limited to, improved electrical power supplies for environmental sensors, electronic sensors, and electric vehicles.

Halogenated volatile organic compounds from the use of chlorine-bleach-containing household products.

PubMed

Odabasi, Mustafa

2008-03-01

Sodium hypochlorite (NaOCl) and many organic chemicals contained in household cleaning products may react to generate halogenated volatile organic compounds (VOCs). Halogenated VOC emissions from eight different chlorine bleach containing household products (pure and diluted) were investigated by headspace experiments. Chloroform and carbon tetrachloride were the leading compounds along with several halogenated compounds in the headspace of chlorine bleach products. One of the most surprising results was the presence of carbon tetrachloride (a probable human carcinogen and a powerful greenhouse gas that was banned for household use by the U.S. Food and Drug Administration) in very high concentrations (up to 101 mg m(-3)). By mixing surfactants or soap with NaOCl, it was shown that the formation of carbon tetrachloride and several other halogenated VOCs is possible. In addition to quantitatively determined halogenated VOCs (n = 15), several nitrogen-containing (n = 4), chlorinated (n = 10), oxygenated compounds (n = 22), and hydrocarbons (n = 14) were identified in the headspace of bleach products. Among these, 1,1-dichlorobutane and 2-chloro-2-nitropropane were the most abundant chlorinated VOCs, whereas trichloronitromethane and hexachloroethane were the most frequently detected ones. Indoor air halogenated VOC concentrations resulting from the use of four selected household products were also measured before, during, and 30 min after bathroom, kitchen, and floor cleaning applications. Chloroform (2.9-24.6 microg m(-3)) and carbon tetrachloride (0.25-459 microg m(-3)) concentrations significantly increased during the use of bleach containing products. During/ before concentration ratios ranged between 8 and 52 (25 +/- 14, average +/- SD) for chloroform and 1-1170 (146 +/- 367, average +/- SD) for carbon tetrachloride, respectively. These results indicated that the bleach use can be important in terms of inhalation exposure to carbon tetrachloride, chloroform and several other halogenated VOCs.

40 CFR 721.8675 - Halogenated pyridines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... treatment will occur, or treatment in a lined, self-contained solar evaporation pond where UV light will... tertiary waste treatment will occur, or treatment in a lined, self-contained solar evaporation pond where...

40 CFR 721.8675 - Halogenated pyridines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... treatment will occur, or treatment in a lined, self-contained solar evaporation pond where UV light will... tertiary waste treatment will occur, or treatment in a lined, self-contained solar evaporation pond where...

Selection criteria for oxidation method in total organic carbon measurement.

PubMed

Yoon, GeunSeok; Park, Sang-Min; Yang, Heuiwon; Tsang, Daniel C W; Alessi, Daniel S; Baek, Kitae

2018-05-01

During the measurement of total organic carbon (TOC), dissolved organic carbon is converted into CO 2 by using high temperature combustion (HTC) or wet chemical oxidation (WCO). However, the criteria for selecting the oxidation methods are not clear. In this study, the chemical structures of organic material were considered as a key factor to select the oxidation method used. Most non-degradable organic compounds showed a similar oxidation efficiency in both methods, including natural organic compounds, dyes, and pharmaceuticals, and thus both methods are appropriate to measure TOC in waters containing these compounds. However, only a fraction of the carbon in the halogenated compounds (perfluorooctanoic acid and trifluoroacetic acid) were oxidized using WCO, resulting in measured TOC values that are considerably lower than those determined by HTC. This result is likely due to the electronegativity of halogen elements which inhibits the approach of electron-rich sulfate radicals in the WCO, and the higher bond strength of carbon-halogen pairs as compared to carbon-hydrogen bonds, which results in a lower degree of oxidation of the compounds. Our results indicate that WCO could be used to oxidize most organic compounds, but may not be appropriate to quantify TOC in organic carbon pools that contain certain halogenated compounds. Copyright © 2018 Elsevier Ltd. All rights reserved.

Halogenated Organic Compounds Identified in Hydraulic Fracturing Wastewaters Using Ultrahigh Resolution Mass Spectrometry.

PubMed

Luek, Jenna L; Schmitt-Kopplin, Philippe; Mouser, Paula J; Petty, William Tyler; Richardson, Susan D; Gonsior, Michael

2017-05-16

Large volumes of water return to the surface following hydraulic fracturing of deep shale formations to retrieve oil and natural gas. Current understanding of the specific organic constituents in these hydraulic fracturing wastewaters is limited to hydrocarbons and a fraction of known chemical additives. In this study, we analyzed hydraulic fracturing wastewater samples using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) as a nontargeted technique to assign unambiguous molecular formulas to singly charged molecular ions. Halogenated molecular formulas were identified and confirmed using isotopic simulation and MS-MS fragmentation spectra. The abundance of halogenated organic compounds in flowback fluids rather than older wastewaters suggested that the observed molecular ions might have been related to hydraulic fracturing additives and related subsurface reactions, such as through the reaction of shale-extracted chloride, bromide, and iodide with strong oxidant additives (e.g., hypochlorite, persulfate, hydrogen peroxide) and subsequently with diverse dissolved organic matter. Some molecular ions matched the exact masses of known disinfection byproducts including diiodoacetic acid, dibromobenzoic acid, and diiodobenzoic acid. The identified halogenated organic compounds, particularly iodinated organic molecules, are absent from inland natural systems and these compounds could therefore play an important role as environmental tracers.

What’s New in Enzymatic Halogenations

PubMed Central

Fujimori, Danica Galoniæ; Walsh, Christopher T.

2007-01-01

Summary The halogenation of thousands of natural products occurs during biosynthesis and often confers important functional properties. While haloperoxidases had been the default paradigm for enzymatic incorporation of halogens, via X+ equivalents into organic scaffolds, a combination of microbial genome sequencing, enzymatic studies and structural biology have provided deep new insights into enzymatic transfer of halide equivalents in three oxidation states. These are: (1) the halide ions (X−) abundant in nature, (2) halogen atoms (X•), and (3) the X+ equivalents. The mechanism of halogen incorporation is tailored to the electronic demands of specific substrates and involves enzymes with distinct redox coenzyme requirements. PMID:17881282

Volatile organic compound emissions from green waste composting: Characterization and ozone formation

NASA Astrophysics Data System (ADS)

Kumar, Anuj; Alaimo, Christopher P.; Horowitz, Robert; Mitloehner, Frank M.; Kleeman, Michael J.; Green, Peter G.

2011-04-01

Composting of green waste separated from the disposed solid waste stream reduces biodegradable inputs into landfills, and contributes valuable soil amendments to agriculture. Agencies in regions with severe air quality challenges, such as California's San Joaquin Valley (SJV), have raised concerns about gases emitted during the composting process, which are suspected to contribute to persistent high levels of ground-level ozone formation. The goal of the current study is to thoroughly characterize volatile organic compound (VOC) emissions from green waste compost piles of different ages (fresh tipped piles, 3-6 day old windrows, and 2-3 week old windrows). Multiple sampling and analytical approaches were applied to ensure the detection of most gaseous organic components emitted. More than 100 VOCs were detected and quantified in this study, including aliphatic alkanes, alkenes, aromatic hydrocarbons, biogenic organics, aldehydes, ketones, alcohols, furans, acids, esters, ether, halogenated hydrocarbons and dimethyl disulfide (DMDS). Alcohols were found to be the dominating VOC in the emissions from a compost pile regardless of age, with fluxes ranging from 2.6 to 13.0 mg m -2 min -1 with the highest emissions coming from the younger composting windrows (3-6 days). Average VOC emissions other than alcohols were determined to be 2.3 mg m -2 min -1 from younger windows, which was roughly two times higher than either the fresh tipping pile (1.2 mg m -2 min -1) or the older windrows (1.4 mg m -2 min -1). It was also observed that the older windrows emit a slightly larger proportion of more reactive compounds. Approximately 90% of the total VOCs were found to have maximum incremental reactivity of less than 2. Net ozone formation potential of the emissions was also assessed.

Microwave assisted pyrolysis of halogenated plastics recovered from waste computers.

PubMed

Rosi, Luca; Bartoli, Mattia; Frediani, Marco

2018-03-01

Microwave Assisted Pyrolysis (MAP) of the plastic fraction of Waste from Electric and Electronic Equipment (WEEE) from end-life computers was run with different absorbers and set-ups in a multimode batch reactor. A large amount of various different liquid fractions (up to 76.6wt%) were formed together with a remarkable reduction of the solid residue (up to 14.2wt%). The liquid fractions were characterized using the following different techniques: FT-IR ATR, 1 H NMR and a quantitative GC-MS analysis. The liquid fractions showed low density and viscosity, together with a high concentration of useful chemicals such as styrene (up to 117.7mg/mL), xylenes (up to 25.6mg/mL for p-xylene) whereas halogenated compounds were absent or present in a very low amounts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Co-combustion of E+E waste plastics in the TAMARA test plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vehlow, J.; Wanke, T.; Bergfeldt, B.

1997-12-01

The co-combustion of different amounts of various plastic fractions of electrical and electronic (E+E) waste together with municipal solid waste has been tested in the Karlsruhe test incinerator TAMARA. The tests revealed no negative influences upon the combustion process. In general the increased heating value of the fuel causes an improved burnout in all residue streams. The halogens Cl and Br added with the plastics are mainly transferred as HCl or HBr into the flue gas. An influence upon the formation of chlorinated dioxins and furans could not be observed. With increasing Br feed bromine containing homologues were detected inmore » the raw gas. The furans formed easier than the dioxins and those homologues carrying one Br atom were by far prevailing. Even at high Br input the total amount of mixed halogenated species was limited to approximately 30% of the total load of such compounds which did not leave the typical operation window for PCDD/PCDF in TAMARA. The co-combustion tests demonstrated that MSW combustion is an ecologically acceptable and economically sound disposal route for limited amounts of specific E+E waste.« less

Hydrodechlorination of polychlorinated biphenyls in contaminated soil from an e-waste recycling area, using nanoscale zerovalent iron and Pd/Fe bimetallic nanoparticles.

PubMed

Chen, Xi; Yao, Xiaoyan; Yu, Chunna; Su, Xiaomei; Shen, Chaofeng; Chen, Chen; Huang, Ronglang; Xu, Xinhua

2014-04-01

Soil pollution by polychlorinated biphenyls (PCBs) arising from the crude disposal and recycling of electronic and electrical waste (e-waste) is a serious issue, and effective remediation technologies are urgently needed. Nanoscale zerovalent iron (nZVI) and bimetallic systems have been shown to promote successfully the destruction of halogenated organic compounds. In the present study, nZVI and Pd/Fe bimetallic nanoparticles synthesized by chemical deposition were used to remove 2,2',4,4',5,5'-hexachlorobiphenyl from deionized water, and then applied to PCBs contaminated soil collected from an e-waste recycling area. The results indicated that the hydrodechlorination of 2,2',4,4',5,5'-hexachlorobiphenyl by nZVI and Pd/Fe bimetallic nanoparticles followed pseudo-first-order kinetics and Pd loading was beneficial to the hydrodechlorination process. It was also found that the removal efficiencies of PCBs from soil achieved using Pd/Fe bimetallic nanoparticles were higher than that achieved using nZVI and that PCBs degradation might be affected by the soil properties. Finally, the potential challenges of nZVI application to in situ remediation were explored.

Impact of bromide on halogen incorporation into organic moieties in chlorinated drinking water treatment and distribution systems.

PubMed

Tan, J; Allard, S; Gruchlik, Y; McDonald, S; Joll, C A; Heitz, A

2016-01-15

The impact of elevated bromide concentrations (399 to 750 μg/L) on the formation of halogenated disinfection by-products (DBPs), namely trihalomethanes, haloacetic acids, haloacetonitriles, and adsorbable organic halogen (AOX), in two drinking water systems was investigated. Bromine was the main halogen incorporated into all of the DBP classes and into organic carbon, even though chlorine was present in large excess to maintain a disinfectant residual. Due to the higher reactivity of bromine compared to chlorine, brominated DBPs were rapidly formed, followed by a slower increase in chlorinated DBPs. Higher bromine substitution and incorporation factors for individual DBP classes were observed for the chlorinated water from the groundwater source (lower concentration of dissolved organic carbon (DOC)), which contained a higher concentration of bromide, than for the surface water source (higher DOC). The molar distribution of adsorbable organic bromine to chlorine (AOBr/AOCl) for AOX in the groundwater distribution system was 1.5:1 and almost 1:1 for the surface water system. The measured (regulated) DBPs only accounted for 16 to 33% of the total organic halogen, demonstrating that AOX measurements are essential to provide a full understanding of the formation of halogenated DBPs in drinking waters. In addition, the study demonstrated that a significant proportion (up to 94%) of the bromide in source waters can be converted AOBr. An evaluation of AOBr and AOCl through a second groundwater treatment plant that uses conventional treatment processes for DOC removal produced 70% of AOX as AOBr, with 69% of the initial source water bromide converted to AOBr. Exposure to organobromine compounds is suspected to result in greater adverse health consequences than their chlorinated analogues. Therefore, this study highlights the need for improved methods to selectively reduce the bromide content in source waters. Copyright © 2015 Elsevier B.V. All rights reserved.

Environmental Compliance Assessment Army Reserve (ECAAR)

DTIC Science & Technology

1993-09-01

and water Spent mixed acid Spent caustic Spent sulfuric acid Potential Consequences: Heat generation, violent reaction. Group 2-A Group 2-B Aluminum Any...methane reforming furnaces, pulping liquor recovery furnaces, combustion devices used in the recovery of sulfur values from spent sulfuric acid...Industry and USEPA Hazardous Waste Hazard No. Hazardous Waste Code* Generic FOO1 The spent halogenated solvents used in degreasing: Trichloroethylene, (t

Process for removing halogenated aliphatic and aromatic compounds from petroleum products

DOEpatents

Googin, J.M.; Napier, J.M.; Travaglini, M.A.

1983-09-20

A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.

Process for removing halogenated aliphatic and aromatic compounds from petroleum products

DOEpatents

Googin, John M.; Napier, John M.; Travaglini, Michael A.

1983-01-01

A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced.

Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene

DOEpatents

Googin, J.M.; Napier, J.M.; Travaglini, M.A.

1982-03-31

A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.

Determination of heavy metals and halogens in plastics from electric and electronic waste.

PubMed

Dimitrakakis, Emmanouil; Janz, Alexander; Bilitewski, Bernd; Gidarakos, Evangelos

2009-10-01

The presence of hazardous substances and preparations in small waste electrical and electronic equipment (sWEEE) found in the residual household waste stream of the city of Dresden, Germany has been investigated. The content of sWEEE plastics in heavy metals and halogens is determined using handheld X-ray fluorescence analysis (HXRF), elemental analysis by means of atomic absorption spectrometry (AAS) and ion exchange chromatography (IEC). Mean value of results for heavy metals in samples (n=51) by AAS are 17.4 mg/kg for Pb, 5.7 mg/kg for Cd, 8.4 mg/kg for Cr. The mass fraction of an additive as shown by HXRF (n=161) can vary over a wide range. Precise deductions as regards sWEEE plastics content in hazardous substances and preparations cannot be made. Additional research would be expedient regarding the influence of hazardous substances to recycling processes, in particular regarding the contamination of clean fractions in the exit streams of a WEEE treatment plant. Suitable standards for calibrating HXRF for use on EEE plastics or complex electr(on)ic components do not exist and should be developed.

Interactions between volatile organic compounds and reactive halogen in the tropical marine atmosphere using WRF-Chem

NASA Astrophysics Data System (ADS)

Badia, Alba; Reeves, Claire E.; Baker, Alex; Volkamer, Rainer; von Glasow, Roland

2016-04-01

Halogen species (chlorine, bromine and iodine) are known to play an important role in the chemistry and oxidizing capacity of the troposphere, particularly in the marine boundary layer (MBL). Reactive halogens cause ozone (O3) destruction, change the HOx and NOX partitioning, affect the oxidation of volatile organic compounds (VOCs) and mercury, reduce the lifetime of methane, and take part in new particle formation. Numerical models predicted that reactive halogen compounds account for 30% of O3 destruction in the MBL and 5-20% globally. There are indications that the chemistry of reactive halogens and oxygenated VOCs (OVOCs) in the tropics are inter-related. Moreover, the presence of aldehydes, such as glyoxal (CHOCHO), has a potential impact on radical cycling and secondary organic aerosol (SOA) formation in the MBL and free troposphere (FT). Model calculations suggest aldehydes to be an important sink for bromine atoms and hence competition for their reaction with O3 forming BrO and so illustrating a link between the cycles of halogens and OVOCs in the marine atmosphere. The main objective of this contribution is to investigate the atmospheric chemistry in the tropical East Pacific with a focus on reactive halogens and OVOCs and their links using the latest version of the Weather Research and Forecasting (WRF) model coupled with Chemistry (WRF-Chem) and field data from the TORERO campaign. WRF-Chem is a highly flexible community model for atmospheric research where aerosol-radiation-cloud feedback processes are taken into account. Our current reaction mechanism in WRF-Chem is based on the MOZART mechanism and has been extended to include bromine, chlorine and iodine chemistry. The MOZART mechanism includes detailed gas-phase chemistry of CHOCHO formation as well as state-of-the-science pathways to form SOA. Oceanic emissions of aldehydes, including CHOCHO, and of organic halogens based on measurements from the TORERO campaign have been added into the model. Sea surface emissions of inorganic iodine are calculated using the parameterisation of Carpenter et al., 2013. Focusing on TORERO observations from the ships and a selected number of flights we present an evaluation of the relevant tropospheric gas-phase chemistry (O3, H2O), inorganic halogen species (BrO, IO), aldehydes (CH3CHO, CHOCHO) and Very Short Lived Halocarbons (VSLH).

A box model study on photochemical interactions between VOCs and reactive halogen species in the marine boundary layer

NASA Astrophysics Data System (ADS)

Toyota, K.; Kanaya, Y.; Takahashi, M.; Akimoto, H.

2003-09-01

A new chemical scheme is developed for the multiphase photochemical box model SEAMAC (size-SEgregated Aerosol model for Marine Air Chemistry) to investigate photochemical interactions between volatile organic compounds (VOCs) and reactive halogen species in the marine boundary layer (MBL). Based primarily on critically evaluated kinetic and photochemical rate parameters as well as a protocol for chemical mechanism development, the new scheme has achieved a near-explicit treatment of oxidative degradation of up to C3-hydrocarbons CH4, C2H6, C3H8, C2H4, C3H6, and C2H2) initiated by reactions with OH radicals, Cl- and Br-atoms, and O3. Rate constants and product yields for reactions involving halogen species are taken from the literature where available, but the majority of them need to be estimated. In particular, addition reactions of halogen atoms with alkenes will result in the formation of halogenated organic intermediates, whose photochemical loss rates are carefully evaluated in the present work. Model calculations with the new chemical scheme reveal that the oceanic emissions of acetaldehyde (CH3CHO) and alkenes (especially C3H6) are important factors for regulating reactive halogen chemistry in the MBL by promoting the conversion of Br atoms into HBr or more stable brominated intermediates in the organic form. The latter include brominated hydroperoxides, bromoacetaldehyde, and bromoacetone, which sequester bromine from reactive inorganic pool. The total mixing ratio of brominated organic species thus produced is likely to reach 10-20% or more of that of inorganic gaseous bromine species over wide regions over the ocean. On the other hand, the reaction between Br atoms and C2H2 is unimportant for determining the degree of bromine activation in the remote MBL. It is suggested that peroxyacetic acid formed via CH3CHO oxidation is one of the important chemical agents for triggering autocatalytic halogen release from sea-salt aerosols. These results imply that reactive halogen chemistry can mediate a link between the oceanic emissions of VOCs and the behaviors of compounds that are sensitive to halogen chemistry such as dimethyl sulfide, NOx, and O3 in the MBL.

A box model study on photochemical interactions between VOCs and reactive halogen species in the marine boundary layer

NASA Astrophysics Data System (ADS)

Toyota, K.; Kanaya, Y.; Takahashi, M.; Akimoto, H.

2004-09-01

A new chemical scheme is developed for the multiphase photochemical box model SEAMAC (size-SEgregated Aerosol model for Marine Air Chemistry) to investigate photochemical interactions between volatile organic compounds (VOCs) and reactive halogen species in the marine boundary layer (MBL). Based primarily on critically evaluated kinetic and photochemical rate parameters as well as a protocol for chemical mechanism development, the new scheme has achieved a near-explicit description of oxidative degradation of up to C3-hydrocarbons (CH4, C2H6, C3H8, C2H4, C3H6, and C2H2) initiated by reactions with OH radicals, Cl- and Br-atoms, and O3. Rate constants and product yields for reactions involving halogen species are taken from the literature where available, but the majority of them need to be estimated. In particular, addition reactions of halogen atoms with alkenes will result in forming halogenated organic intermediates, whose photochemical loss rates are carefully evaluated in the present work. Model calculations with the new chemical scheme reveal that the oceanic emissions of acetaldehyde (CH3CHO) and alkenes (especially C3H6) are important factors for regulating reactive halogen chemistry in the MBL by promoting the conversion of Br atoms into HBr or more stable brominated intermediates in the organic form. The latter include brominated hydroperoxides, bromoacetaldehyde, and bromoacetone, which sequester bromine from a reactive inorganic pool. The total mixing ratio of brominated organic species thus produced is likely to reach 10-20% or more of that of inorganic gaseous bromine species over wide regions over the ocean. The reaction between Br atoms and C2H2 is shown to be unimportant for determining the degree of bromine activation in the remote MBL. These results imply that reactive halogen chemistry can mediate a link between the oceanic emissions of VOCs and the behaviors of compounds that are sensitive to halogen chemistry such as dimethyl sulfide, NOx, and O3 in the MBL.

Experimental and computational evidence of halogen bonds involving astatine

NASA Astrophysics Data System (ADS)

Guo, Ning; Maurice, Rémi; Teze, David; Graton, Jérôme; Champion, Julie; Montavon, Gilles; Galland, Nicolas

2018-03-01

The importance of halogen bonds—highly directional interactions between an electron-deficient σ-hole moiety in a halogenated compound and an acceptor such as a Lewis base—is being increasingly recognized in a wide variety of fields from biomedicinal chemistry to materials science. The heaviest halogens are known to form stronger halogen bonds, implying that if this trend continues down the periodic table, astatine should exhibit the highest halogen-bond donating ability. This may be mitigated, however, by the relativistic effects undergone by heavy elements, as illustrated by the metallic character of astatine. Here, the occurrence of halogen-bonding interactions involving astatine is experimentally evidenced. The complexation constants of astatine monoiodide with a series of organic ligands in cyclohexane solution were derived from distribution coefficient measurements and supported by relativistic quantum mechanical calculations. Taken together, the results show that astatine indeed behaves as a halogen-bond donor—a stronger one than iodine—owing to its much more electrophilic σ-hole.

How technology transfer issues are managed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sink, C.H.; Easley, K.R.

1991-12-31

In 1989, Secretary of Energy James Watkins made a commitment to accelerate DOE compliance with all applicable laws and standards aimed at protecting human health and the environment. At a minimum, this pledge requires the remediation of the 1989 inventory of chemical, radioactive, and mixed wastes at DOE production sites by 2019. The 1989 Complex inventory consisted of more than 3,700 sites, encompassing more than 26,000 acres contaminated with radioactive, hazardous, and mixed wastes. In addition, over 500 surplus sites are awaiting decontamination and decommissioning (D and D), and approximately 5,000 peripheral properties have contaminated soils (e.g., uranium tailings). Moreover,more » these problems exist at both inactive sites, where the primary focus is on environmental restoration, and at active sites, where the major emphasis is on improved waste management techniques. Although some of DOE`s problems are considered unique due to radioactivity, most forms of contamination resident in the Complex are not; rather, contaminants such as waste chemicals (e.g., inorganics), organics (e.g., fuels and solvents), halogenated organics (e.g., PCBs) and heavy metals commonly result in conventional industrial processes. Although certain other forms of contamination are more unique to DOE operations (e.g., radioactive materials, explosives, and pyrophorics), they are not exclusive to DOE. As DOE develops innovative solutions to these and related waste problems, it is imperative that technology systems and lessons learned be transferred from DOE sites and its R and D laboratories to private industry to maximize the nation`s return on environmental management technology investments.« less

Headspace GC-MS Analysis of Halogenated Volatile Organic Compounds in Aqueous Samples: An Experiment for General Chemistry Laboratory

ERIC Educational Resources Information Center

Keller, John W.; Fabbri, Cindy E.

2012-01-01

Analysis of halogenated volatile organic compounds (HVOCs) by GC-MS demonstrates the use of instrumentation in the environmental analysis of pollutant molecules and enhances student understanding of stable isotopes in nature. In this experiment, students separated and identified several HVOCs that have been implicated as industrial groundwater…

Environmental and human exposure to persistent halogenated compounds derived from e-waste in China.

PubMed

Ni, Hong-Gang; Zeng, Hui; Tao, Shu; Zeng, Eddy Y

2010-06-01

Various classes of persistent halogenated compounds (PHCs) can be released into the environment due to improper handling and disposal of electronic waste (e-waste), which creates severe environmental problems and poses hazards to human health as well. In this review, polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), tetrabromobisphenol A (TBBPA), polybrominated phenols (PBPs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and chlorinated polycyclic aromatic hydrocarbons (ClPAHs) are the main target contaminants for examination. As the world's largest importer and recycler of e-waste, China has been under tremendous pressure to deal with this huge e-waste situation. This review assesses the magnitude of the e-waste problems in China based on data obtained from the last several years, during which many significant investigations have been conducted. Comparative analyses of the concentrations of several classes of toxic compounds, in which e-waste recycling sites are compared with reference sites in China, have indicated that improper e-waste handling affects the environment of dismantling sites more than that of control sites. An assessment of the annual mass loadings of PBDEs, PBBs, TBBPA, PBPs, PCDD/Fs, and ClPAHs from e-waste in China has shown that PBDEs are the dominant components of PHCs in e-waste, followed by ClPAHs and PCDD/Fs. The annual loadings of PBDEs, ClPAHs, and PCDD/Fs emission were estimated to range from 76,200 to 182,000, 900 to 2,000 and 3 to 8 kg/year, respectively. However, PCDD/Fs and ClPAHs should not be neglected because they are also primarily released from e-waste recycling processes. Overall, the magnitude of human exposure to these toxics in e-waste sites in China is at the high end of the global range. Copyright 2010 SETAC.

Methods of Responsibly Managing End-of-Life Foams and Plastics Containing Flame Retardants: Part II.

PubMed

Lucas, Donald; Petty, Sara M; Keen, Olya; Luedeka, Bob; Schlummer, Martin; Weber, Roland; Yazdani, Ramin; Riise, Brian; Rhodes, James; Nightingale, Dave; Diamond, Miriam L; Vijgen, John; Lindeman, Avery; Blum, Arlene; Koshland, Catherine P

2018-06-01

This is Part II of a review covering the wide range of issues associated with all aspects of the use and responsible disposal of foam and plastic wastes containing toxic or potentially toxic flame retardants. We identify basic and applied research needs in the areas of responsible collection, pretreatment, processing, and management of these wastes. In Part II, we explore alternative technologies for the management of halogenated flame retardant (HFR) containing wastes, including chemical, mechanical, and thermal processes for recycling, treatment, and disposal.

Halogen radicals contribute to photooxidation in coastal and estuarine waters

PubMed Central

Parker, Kimberly M.; Mitch, William A.

2016-01-01

Although halogen radicals are recognized to form as products of hydroxyl radical (•OH) scavenging by halides, their contribution to the phototransformation of marine organic compounds has received little attention. We demonstrate that, relative to freshwater conditions, seawater halides can increase photodegradation rates of domoic acid, a marine algal toxin, and dimethyl sulfide, a volatile precursor to cloud condensation nuclei, up to fivefold. Using synthetic seawater solutions, we show that the increased photodegradation is specific to dissolved organic matter (DOM) and halides, rather than other seawater salt constituents (e.g., carbonates) or photoactive species (e.g., iron and nitrate). Experiments in synthetic and natural coastal and estuarine water samples demonstrate that the halide-specific increase in photodegradation could be attributed to photochemically generated halogen radicals rather than other photoproduced reactive intermediates [e.g., excited-state triplet DOM (3DOM*), reactive oxygen species]. Computational kinetic modeling indicates that seawater halogen radical concentrations are two to three orders of magnitude greater than freshwater •OH concentrations and sufficient to account for the observed halide-specific increase in photodegradation. Dark •OH generation by gamma radiolysis demonstrates that halogen radical production via •OH scavenging by halides is insufficient to explain the observed effect. Using sensitizer models for DOM chromophores, we show that halogen radicals are formed predominantly by direct oxidation of Cl− and Br− by 3DOM*, an •OH-independent pathway. Our results indicate that halogen radicals significantly contribute to the phototransformation of algal products in coastal or estuarine surface waters. PMID:27162335

Dual mechanochemical immobilization of heavy metals and decomposition of halogenated compounds in automobile shredder residue using a nano-sized metallic calcium reagent.

PubMed

Mallampati, Srinivasa Reddy; Lee, Byoung Ho; Mitoma, Yoshiharu; Simion, Cristian

2016-11-01

Simultaneous immobilization of heavy metals and decomposition of halogenated organic compounds in different fractions of automobile shredder residue (ASR) were achieved with a nano-sized metallic calcium through a 60-min ball milling treatment. Heavy metal (HM) immobilization and chlorinated/brominated compound (CBC) decomposition efficiencies both reached 90-100 %, after ball milling with nanometallic calcium/calcium oxide (Ca/CaO) dispersion, regardless of ASR particle size (1.0, 0.45-1.0, and 0.250 mm). Concentrations of leachable HMs substantially decreased to a level lower than the regulatory standard limits (Co and Cd 0.3 mg L -1 ; Cr 1.5 mg L -1 ; Fe, Pb, and Zn 3.0 mg L -1 ; Mn and Ni 1 mg L -1 ) proposed by the Korean hazardous waste elution standard regulatory threshold. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) element maps/spectra showed that while the amounts of HMs and CBCs detectable in ASR significantly decreased, the calcium mass percentage increased. X-ray powder diffraction (XRD) patterns indicate that the main fraction of enclosed/bound materials on ASR includes Ca-associated crystalline complexes that remarkably inhibit HM desorption and simultaneously transform dangerous CBCs into harmless compounds. The use of a nanometallic Ca/CaO mixture in a mechanochemical process to treat hazardous ASR (dry conditions) is an innovative approach to remediate cross-contaminated residues with heavy metals and halogenated compounds.

Release of chlorinated, brominated and mixed halogenated dioxin-related compounds to soils from open burning of e-waste in Agbogbloshie (Accra, Ghana).

PubMed

Tue, Nguyen Minh; Goto, Akitoshi; Takahashi, Shin; Itai, Takaaki; Asante, Kwadwo Ansong; Kunisue, Tatsuya; Tanabe, Shinsuke

2016-01-25

Although complex mixtures of dioxin-related compounds (DRCs) can be released from informal e-waste recycling, DRC contamination in African e-waste recycling sites has not been investigated. This study examined the concentrations of DRCs including chlorinated, brominated, mixed halogenated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs, PBDD/Fs, PXDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in surface soil samples from the Agbogbloshie e-waste recycling site in Ghana. PCDD/F and PBDD/F concentrations in open burning areas (18-520 and 83-3800 ng/g dry, respectively) were among the highest reported in soils from informal e-waste sites. The concentrations of PCDFs and PBDFs were higher than those of the respective dibenzo-p-dioxins, suggesting combustion and PBDE-containing plastics as principal sources. PXDFs were found as more abundant than PCDFs, and higher brominated analogues occurred at higher concentrations. The median total WHO toxic equivalent (TEQ) concentration in open burning soils was 7 times higher than the U.S. action level (1000 pg/g), with TEQ contributors in the order of PBDFs>PCDD/Fs>PXDFs. DRC emission to soils over the e-waste site as of 2010 was estimated, from surface soil lightness based on the correlations between concentrations and lightness, at 200mg (95% confidence interval 93-540 mg) WHO-TEQ over three years. People living in Agbogbloshie are potentially exposed to high levels of not only chlorinated but also brominated DRCs, and human health implications need to be assessed in future studies. Copyright © 2015 Elsevier B.V. All rights reserved.

SUBSTITUTION REACTIONS FOR THE DETOXIFICATION OF HAZARDOUS CHEMICALS

EPA Science Inventory

Chemical Treatment is one of several treatment techniques used for the remediation of toxic and hazardous chemicals. Chemical treatment in this report is defined as substitution of halogens by hydrogens for the conversion of halogenated organic toxicant into its native hydrocarb...

Photolytic dehalogenation of disinfection byproducts in water by natural sunlight irradiation.

PubMed

Abusallout, Ibrahim; Hua, Guanghui

2016-09-01

The aqueous photolysis of halogenated disinfection byproducts (DBPs) by natural sunlight irradiation was studied to determine their photolytic dehalogenation kinetics. Total organic halogen analysis was used to quantify the dehalogenation extents of DBPs during outdoor photolysis experiments. Dichloroacetamide, chloral hydrate, chloroform, dichloroacetonitrile, monochloro-, monobromo-, dichloro-, dibromo-, and trichloroacetic acids were generally resistant to photolytic dehalogenation and showed less than 10% reduction after 6 h sunlight irradiation. Monoiodoacetic acid, tribromoacetic acid, bromoform, dibromoacetonitrile, and trichloronitromethane showed moderate to high dehalogenation degrees with half-lives of 4.0-19.3 h. Diiodoacetic acid, triiodoacetic acid, and iodoform degraded rapidly under the sunlight irradiation and exhibited half-lives of 5.3-10.2 min. In general, the photosensitive cleavage of carbon-halogen bonds of DBPs increased with increasing number of halogens (tri- > di- > mono-halogenated) and size of the substituted halogens (I > Br > Cl). Nitrate, nitrite, and pH had little impact on the photodehalogenation of DBPs under typical levels in surface waters. The presence of natural organic matter (NOM) inhibited the photodehalogenation of DBPs by light screening. The NOM inhibiting effects were more pronounced for the fast degrading iodinated DBPs. The results of this study improve our understanding about the photolytic dehalogenation of wastewater-derived DBPs in surface waters during water reuse. Published by Elsevier Ltd.

The Halogen Bond in the Design of Functional Supramolecular Materials: Recent Advances

PubMed Central

2013-01-01

Halogen bonding is an emerging noncovalent interaction for constructing supramolecular assemblies. Though similar to the more familiar hydrogen bonding, four primary differences between these two interactions make halogen bonding a unique tool for molecular recognition and the design of functional materials. First, halogen bonds tend to be much more directional than (single) hydrogen bonds. Second, the interaction strength scales with the polarizability of the bond-donor atom, a feature that researchers can tune through single-atom mutation. In addition, halogen bonds are hydrophobic whereas hydrogen bonds are hydrophilic. Lastly, the size of the bond-donor atom (halogen) is significantly larger than hydrogen. As a result, halogen bonding provides supramolecular chemists with design tools that cannot be easily met with other types of noncovalent interactions and opens up unprecedented possibilities in the design of smart functional materials. This Account highlights the recent advances in the design of halogen-bond-based functional materials. Each of the unique features of halogen bonding, directionality, tunable interaction strength, hydrophobicity, and large donor atom size, makes a difference. Taking advantage of the hydrophobicity, researchers have designed small-size ion transporters. The large halogen atom size provided a platform for constructing all-organic light-emitting crystals that efficiently generate triplet electrons and have a high phosphorescence quantum yield. The tunable interaction strengths provide tools for understanding light-induced macroscopic motions in photoresponsive azobenzene-containing polymers, and the directionality renders halogen bonding useful in the design on functional supramolecular liquid crystals and gel-phase materials. Although halogen bond based functional materials design is still in its infancy, we foresee a bright future for this field. We expect that materials designed based on halogen bonding could lead to applications in biomimetics, optics/photonics, functional surfaces, and photoswitchable supramolecules. PMID:23805801

TRANSFORMATION OF HALOGENATED PBTS WITH NANOSCALE BIMETALLIC PARTICLES

EPA Science Inventory

Formation of halogen-induced secondary organic aerosol (XOA)

NASA Astrophysics Data System (ADS)

Kamilli, Katharina; Ofner, Johannes; Zetzsch, Cornelius; Held, Andreas

2013-04-01

Reactive halogen species (RHS) are very important due to their potential of stratospheric ozone depletion and surface ozone destruction. RHS seem to interact with precursors of secondary organic aerosol (SOA) similarly to common atmospheric oxidants like OH radicals and ozone. The potential interaction of RHS with preformed SOA has recently been studied (Ofner et al., 2012). Although aerosol formation from reaction of RHS with typical SOA precursors was previously studied (e.g. Cai et al., 2006), no data are available on bromine-induced aerosol formation from organic precursors yet. An aerosol smog-chamber was used to examine the halogen-induced secondary organic aerosol (XOA) formation under atmospheric conditions using simulated sunlight. With a concentration of 10 ppb for the organic precursor, 2 ppb for molecular chlorine, and 10 ppb for molecular bromine, the experimental setup is close to ambient conditions. By combined measurements of the aerosol size distribution, ozone and NOx mixing ratios, as well as the decay of the organic precursor, aerosol yields and aerosol growth rates were determined. The decay of the organic precursor was analyzed by capillary gas chromatography coupled with flame-ionization detection (GC-FID) and the aerosol size distribution was measured using a Scanning Mobility Particle Sizer (SMPS). Additionally, with the decay rate of the precursor and the calculated photolysis rates of molecular halogen species, based on the well-known spectrum of the solar simulator, mechanistic details on the XOA formation pathways can be determined. We observed XOA formation even at very low precursor and RHS concentrations with a diameter mode at 10-20 nm and a number concentration up to 1000000 particles cm-3. While the XOA formation from chlorine is very rapid, the interaction of bromine with the organic precursors is about five times slower. The aerosol yield reached maximum values of 0.01 for the reaction of chlorine with α-pinene and 0.0004 for bromine with α-pinene. This work was funded by German Research Foundation (DFG) under grants HE 5214/5-1 and ZE792/5-2. References: Cai, X., and Griffin, R. J.: Secondary aerosol formation from the oxidation of biogenic hydrocarbons by chlorine atoms, J. Geophys. Res., 111, D14206/14201-D14206/14214, 2006. Ofner, J. Balzer, N., Buxmann, J., Grothe, H., Schmitt-Kopplin, Ph., Platt, U., and Zetzsch, C., Halogenation processes of secondary organic aerosol and implications on halogen release mechanisms, Atmos. Chem. Phys. Discuss. 12, 2975-3017, 2012.

Impact of enhanced ozone deposition and halogen chemistry on model performance

EPA Science Inventory

In this study, an enhanced ozone deposition scheme due to the interaction of iodide in sea-water and atmospheric ozone and the detailed chemical reactions of organic and inorganic halogen species are incorporated into the hemispheric Community Multiscale Air Quality model. Prelim...

Remarkable effect of halogenation of aromatic compounds on efficiency of nanowire formation through polymerization/crosslinking by high-energy single particle irradiation

NASA Astrophysics Data System (ADS)

Horio, Akifumi; Sakurai, Tsuneaki; Kayama, Kazuto; Lakshmi, G. B. V. S.; Kumar Avasthi, Devesh; Sugimoto, Masaki; Yamaki, Tetsuya; Chiba, Atsuya; Saito, Yuichi; Seki, Shu

2018-01-01

Irradiation of high-energy ion particles on organic films induced solid-state polymerization and crosslinking reactions of the materials along the ion trajectories, resulting in the formation of insoluble uniform nanowires with a precise diameter. The nanowires were isolated by the development process i.e. the irradiated film was immersed in organic solvents, and their morphology was visualized by atomic force microscopy. The target organic materials are 4-vinyltriphenylamine, poly(4-vinyltriphenylamine), and polystyrene derivatives with/without the partial substitutions by halogen atoms. It was found that 4-vinyltriphenylamines, in spite of their small molecular sizes, afforded nanowires more clearly than poly(4-vinyltriphenylamine)s. Moreover, the efficiency of demonstrated polymerization/crosslinking reactions obviously depends on the substituted halogen atom species. The averaged diameters of nanowires from bromo- or iodo- substituted 4-vinyltriphenylamine (9.3 and 9.4 nm, respectively) were larger than that obtained from simple 4-vinyltriphenylamine (6.8 nm). The remarkable effect of halogenation of aromatic compounds on the efficiency of the radiation-induced reactions was also observed for polystyrene derivatives. This contrast was considered to originate from the sum of the efficiency of elementary reactions including dissociative electron attachment.

C–H bond halogenation catalyzed or mediated by copper: an overview

PubMed Central

Hao, Wenyan

2015-01-01

Summary Carbon–halogen (C–X) bonds are amongst the most fundamental groups in organic synthesis, they are frequently and widely employed in the synthesis of numerous organic products. The generation of a C–X bond, therefore, constitutes an issue of universal interest. Herein, the research advances on the copper-catalyzed and mediated C–X (X = F, Cl, Br, I) bond formation via direct C–H bond transformation is reviewed. PMID:26664634

Halogen-bonding-triggered supramolecular gel formation

NASA Astrophysics Data System (ADS)

Meazza, Lorenzo; Foster, Jonathan A.; Fucke, Katharina; Metrangolo, Pierangelo; Resnati, Giuseppe; Steed, Jonathan W.

2013-01-01

Supramolecular gels are topical soft materials involving the reversible formation of fibrous aggregates using non-covalent interactions. There is significant interest in controlling the properties of such materials by the formation of multicomponent systems, which exhibit non-additive properties emerging from interaction of the components. The use of hydrogen bonding to assemble supramolecular gels in organic solvents is well established. In contrast, the use of halogen bonding to trigger supramolecular gel formation in a two-component gel (‘co-gel’) is essentially unexplored, and forms the basis for this study. Here, we show that halogen bonding between a pyridyl substituent in a bis(pyridyl urea) and 1,4-diiodotetrafluorobenzene brings about gelation, even in polar media such as aqueous methanol and aqueous dimethylsulfoxide. This demonstrates that halogen bonding is sufficiently strong to interfere with competing gel-inhibitory interactions and create a ‘tipping point’ in gel assembly. Using this concept, we have prepared a halogen bond donor bis(urea) gelator that forms co-gels with halogen bond acceptors.

Design and verification of halogen-bonding system at the complex interface of human fertilization-related MUP PDZ5 domain with CAMK's C-terminal peptide.

PubMed

Wang, Juan; Guo, Yunjie; Zhang, Xue

2018-02-01

Calmodulin-dependent protein kinase (CAMK) is physiologically activated in fertilized human oocytes and is involved in the Ca 2+ response pathways that link the fertilization calmodulin signal to meiosis resumption and cortical granule exocytosis. The kinase has an unstructured C-terminal tail that can be recognized and bound by the PDZ5 domain of its cognate partner, the multi-PDZ domain protein (MUP). In the current study, we reported a rational biomolecular design of halogen-bonding system at the complex interface of CAMK's C-terminal peptide with MUP PDZ5 domain by using high-level computational approaches. Four organic halogens were employed as atom probes to explore the structural geometry and energetic property of designed halogen bonds in the PDZ5-peptide complex. It was found that the heavier halogen elements such as bromine Br and iodine I can confer stronger halogen bond but would cause bad atomic contacts and overlaps at the complex interface, while fluorine F cannot form effective halogen bond in the complex. In addition, the halogen substitution at different positions of peptide's aromatic ring would result in distinct effects on the halogen-bonding system. The computational findings were then verified by using fluorescence analysis; it is indicated that the halogen type and substitution position play critical role in the interaction strength of halogen bonds, and thus the PDZ5-peptide binding affinity can be improved considerably by optimizing their combination. Copyright © 2017 Elsevier Ltd. All rights reserved.

Exhaled human breath measurement method for assessing exposure to halogenated volatile organic compounds.

PubMed

Pleil, J D; Lindstrom, A B

1997-05-01

The organic constituents of exhaled human breath are representative of blood-borne concentrations through gas exchange in the blood/breath interface in the lungs. The presence of specific compounds can be an indicator of recent exposure or represent a biological response of the subject. For volatile organic compounds (VOCs), sampling and analysis of breath is preferred to direct measurement from blood samples because breath collection is noninvasive, potentially infectious waste is avoided, and the measurement of gas-phase analytes is much simpler in a gas matrix rather than in a complex biological tissue such as blood. To exploit these advantages, we have developed the "single breath canister" (SBC) technique, a simple direct collection method for individual alveolar breath samples, and adapted conventional gas chromatography-mass spectrometry analytical methods for trace-concentration VOC analysis. The focus of this paper is to describe briefly the techniques for making VOC measurements in breath, to present some specific applications for which these methods are relevant, and to demonstrate how to estimate exposure to example VOCs on the basis of breath elimination. We present data from three different exposure scenarios: (a) vinyl chloride and cis-1,2-dichloroethene from showering with contaminated water from a private well, (b) chloroform and bromodichloromethane from high-intensity swimming in chlorinated pool water, and (c) trichloroethene from a controlled exposure chamber experiment. In all cases, for all subjects, the experiment is the same: preexposure breath measurement, exposure to halogenated VOC, and a postexposure time-dependent series of breath measurements. Data are presented only to demonstrate the use of the method and how to interpret the analytical results.

Biodegradation of Trihalomethanes and Other Halogenated Aliphatic Compounds

NASA Technical Reports Server (NTRS)

Smith, G. B.

1996-01-01

The biological dehalogenation of common water pollutants such as trichloromethane (chloroform) and other halogenated aliphatic compounds was the subject of this project. Samples from diverse water environments such as from groundwater contaminated with halogenated compounds and wastewaters from regional treatment plants were studied to identify conditions that favor certain dehalogenation reactions over others. Gene probe analyses of DNA extracted from the dichlormethane-degrading wastewater indicated the presence of the gene coding for dichloromethane dehalogenase, indicating the genetic basis for the dechlorination activity observed. These studies indicate that methanogenic bacteria are the organisms responsible for the chloroform dechlorination. Dechlorination of a common chlorofluorocarbon (CFC-11) was identified in samples taken from a regional aquifer contaminated with halogenated aliphatic compounds.

A simple and automated sample preparation system for subsequent halogens determination: Combustion followed by pyrohydrolysis.

PubMed

Pereira, L S F; Pedrotti, M F; Vecchia, P Dalla; Pereira, J S F; Flores, E M M

2018-06-20

A simple and automated system based on combustion followed by a pyrohydrolysis reaction was proposed for further halogens determination. This system was applied for digestion of soils containing high (90%) and also low (10%) organic matter content for further halogens determination. The following parameters were evaluated: sample mass, use of microcrystalline cellulose and heating time. For analytes absorption, a diluted alkaline solution (6 mL of 25 mmol L -1  NH 4 OH) was used in all experiments. Up to 400 mg of soil with high organic matter content and 100 mg of soil with low organic matter content (mixed with 400 mg of cellulose) could be completely digested using the proposed system. Quantitative results for all halogens were obtained using less than 12 min of sample preparation step (about 1.8 min for sample combustion and 10 min for pyrohydrolysis). The accuracy was evaluated using a certified reference material of coal and spiked samples. No statistical difference was observed between the certified values and results obtained by the proposed method. Additionally, the recoveries obtained using spiked samples were in the range of 98-103% with relative standard deviation values lower than 5%. The limits of quantification obtained for F, Cl, Br and I for soil with high (400 mg of soil) and low (100 mg of soil) organic matter were in the range of 0.01-2 μg g -1 and 0.07-59 μg g -1 , respectively. The proposed system was considered as a simple and suitable alternative for soils digestion for further halogens determination by ion chromatography and inductively coupled plasma mass spectrometry techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

A marine sink for chlorine in natural organic matter [Natural chlorination of marine organic matter

DOE PAGES

Leri, Alessandra C.; Northrup, Paul A.; Mayer, Lawrence M.; ...

2015-07-06

Chloride, Cl –, is the most abundant solute in seawater, amounting to 55% of ions by weight. Cl – is more difficult to oxidize than bromide, and marine halogenating enzymes tend to be bromoperoxidases that are incapable of forming organochlorines. Consequently, most halogenated natural products identified in the marine environment are organobromines. Known exceptions include small quantities of volatile chlorocarbons emitted by marine algae and dissolved chlorinated benzoic acids.

Remedial Investigation/Feasibility Study/Interim Response Actions

DTIC Science & Technology

1988-03-25

organosulfur compounds (CC/FP), organophosphorus compounds (CC/FPD), hydrocarbons (CC/FID), volatile aromatic compounds (GC/ PID ), volatile halogenated...ICP metals, mercury and arsenic (AA). Water samples are being analyzed for volatile halogenated organics (GC/CON), volatile aromatic organics (GC/ PID ...Feb Mar Apr May Jun Jul Aug SepSI - I I I I I • .. I I I ----+----- 685 27-90 so ONSITE DISPOSAL FACILITY .i * 686 27-01 Prep FLUE Plan Fz=m8u> 6e7

Waste dumps in local communities in developing countries and hidden danger to health.

PubMed

Anetor, Gloria O

2016-07-01

The rapid industrialisation and urbanisation fuelled by a fast-growing population has led to the generation of a huge amount of waste in most communities in developing countries. The hidden disorders and health dangers in waste dumps are often ignored. The waste generated in local communities is usually of a mixed type consisting of domestic waste and waste from small-scale industrial activities. Among these wastes are toxic metals, lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), halogenated organic compounds, plastics, remnants of paints that are themselves mixtures of hazardous substances, hydrocarbons and petroleum product-contaminated devices. Therefore, there is the urgent need to create an awareness of the harmful health effect of toxic wastes in developing countries, especially Nigeria. This is a review aimed at creating awareness on the hidden dangers of waste dumps to health in local communities in developing countries. Many publications in standard outlets use the following keywords: cancer, chemical toxicity, modern environmental health hazards, waste management and waste speciation in PubMed, ISI, Toxbase environmental digest, related base journals, and some standard textbooks, as well as the observation of the researcher between 1959 and 2014. Studies revealed the preponderance of toxic chemicals such as Pb, Cd, As and Hg in dump sites that have the risk of entering food chain and groundwater supplies, and these can give rise to endemic malnutrition and may also increase susceptibility to mutagenic substances, thereby increasing the incidence of cancer in developing countries. Industrialisation and urbanisation have brought about a change in the waste that is generated in contemporary communities in developing countries. Therefore, there is the need to embrace speciation and sound management of waste, probably including bioremediation. The populations in the local communities need regulatory agencies who are health educators as positive change agents. © Royal Society for Public Health 2016.

40 CFR 63.1326 - Batch process vents-recordkeeping provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

...): (i) For an incinerator or non-combustion control device, the percent reduction of organic HAP or TOC... introduced with combustion air or used as a secondary fuel and is not mixed with the primary fuel, the... scrubber or other halogen reduction device following a combustion device to control halogenated batch...

Polychlorinated biphenyls and their hydroxylated metabolites in the serum of e-waste dismantling workers from eastern China.

PubMed

Ma, Shengtao; Ren, Guofa; Zeng, Xiangying; Yu, Zhiqiang; Sheng, Guoying; Fu, Jiamo

2017-05-05

A number of studies have reported on the exposure of e-waste dismantling workers to significantly high concentrations of halogenated organic pollutants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers. Such exposure can have adverse health effects. However, little information on the metabolites of these contaminants exists. In this study, we investigated PCBs levels and their hydroxylated metabolites (OH-PCB) in the serum of e-waste workers in Taizhou in eastern China. Our results indicate elevated PCB and OH-PCB levels in the serum of the workers, with medians of 443.7 and 133.9 ng/g lw, respectively. Tri- to hexachlorinated PCB congeners were the dominant homologue groups in all of the samples. 4-OH-CB107 was the predominant homologue among the hydroxylated metabolites, accounting for 88.9% of the total OH-PCB concentrations. While dietary sources (e.g., fish) appear to be an important route for PCB accumulation in non-occupational exposure groups, exposure via ingestion of house dust and inhalation of pollutants derived from the recycling of PCB-containing e-wastes may primarily contribute to the high body burden observed in the occupational groups. Since we found concentrations of metabolites higher than those of their parent compounds, further studies need to pay more attention to their bioaccumulation and toxicity.

The gas-chromatographic and gas-chromatographic-mass-spectrometric identification of halogen-containing organic compounds

NASA Astrophysics Data System (ADS)

Gidaspov, B. V.; Zenkevich, I. G.; Rodin, A. A.

1989-09-01

The problem of identifying halogen-containing organic compounds in their gas-chromatographic and gas-chromatographic-mass-spectrometric (GC-MS) determination in different materials has been examined. Particular attention has been paid not to the complete characterisation of methods for carrying out this analysis but to the most important problem of increasing the selectivity at the stages of sampling, separation, and interpretation of the gas-chromatographic and GC-MS information. The bibliography contains 292 references.

40 CFR 63.491 - Batch front-end process vents-recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (b)(2): (i) For an incinerator or non-combustion control device, the percent reduction of organic HAP... the process vent stream is introduced with combustion air or is used as a secondary fuel and is not... combustion device to control halogenated batch front-end process vents or halogenated aggregate batch vent...

40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for the... substance may cause internal organ effects (kidney and blood). The requirements of this section do not apply... processors of this substance as specified in § 721.125 (a), (b), (c), (d), (f), (g), (h), and (i). (2...

Health assessment for Cemetery Industrial Waste Dump, Rose Township, Michigan, Region 5. CERCLIS No. MID980794663. Preliminary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-06-24

The Cemetery Industrial Waste Dump National Priorities List Site is located in Rose Township, Oakland County, Michigan. Contamination at the site consists of an unknown quantity of buried drums which, when sampled, indicated the presence of metals, polychlorinated biphenyls (PCBs), and halogenated organic compounds. The site is approximately 2-4 acres. In the late 1960s 300 to 600 drums, which contained unknown industrial waste, were illegally buried at the site. Sampling of the drums on-site indicated the presence of several contaminants including: benzene, chlorobenzene, PCBs, arsenic, cadmium, lead, and others. Lead was detected in one monitoring well at 96 micro g/Lmore » and one residential well at a concentration of 61 micro g/L, both are above the Maximum Contaminant Level of 50 micro g/L. Arsenic was detected in the soil at a concentration of 12 mg/Kg. The site is of potential public health concern because of the risk to human health that could result from possible exposure to hazardous substances at levels that may result in adverse health effects. Potential human exposure pathways include direct dermal contact with the soil, the buried drums, and/or ground water; and ingestion of ground water.« less

Formation of halogenated organics during waste-water disinfection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, P.C.; Brown, R.A.; Wiseman, J.F.

The research examined the formation of trihalomethanes (THMs) and total organic halides (TOX) during wastewater chlorination at three wastewater treatment plants in the central Piedmont of North Carolina. Secondary effluent samples were collected before and after the addition of chlorine at each of the three treatment facilities; chlorinated samples were taken from various locations within the chlorine contact chambers and at the plant discharge. Water samples were also collected upstream and downstream from two of the plant outfalls to determine the increase and persistence of THMs and TOX below each plant. TOX and THM formation was evaluated in terms ofmore » effluent wastewater quality (e.g., residual chemical oxygen demand, total organic carbon and ammonia concentration), chlorine dose, chlorine contacting system, methods of chlorine addition, and chlorine-to-ammonia ratio. The results showed that TOX was present in the unchlorinated wastewater and that additional TOX was formed immediately after chlorine addition. Small to insignificant amounts of THMS were detected. TOX formation did not increase with increasing contact time, due to the rapid depletion of free chlorine and the formation of combined chlorine in the chlorine contact chamber.« less

Behaviour of antimony during thermal treatment of Sb-rich halogenated waste.

PubMed

Klein, J; Dorge, S; Trouvé, G; Venditti, D; Durécu, S

2009-07-30

Antimony compounds have a wide range of industrial applications, particularly as additives in flame retardants. To ensure environmentally friendly waste incineration of Sb-rich wastes, it is essential to strengthen the knowledge about the fate of antimony and the potential formation of harmful species. Investigations should be conducted particularly in relation with the main operational parameters controlling the process, chiefly temperature, residence time and air supply in the oven and in the post-combustion zone, prior final adapted cleaning of the flue-gas stream. Experimental studies focusing on antimony behaviour were undertaken through laboratory-scale thermal treatment at 850 degrees C and 1100 degrees C of a Sb-rich halogenated waste, originating from the sector of flame retardants formulation. The configuration of our laboratory experimental device allowed to achieve only low oxidative conditions in the waste bed, but high oxidative strength coupled with high temperature and sufficient gas residence time in the post-combustion zone, as prescribed during the incineration of hazardous wastes. Atomic absorption spectroscopy was used to assess the partition of antimony in the different compartments of the process. The oxidation degree of antimony in the gas-phase was determined by the use of electrochemical techniques, namely polarography coupled with anodic stripping voltamperometry. The partition of antimony between the residual ash and the gas-phase under moderate oxidative conditions in the waste bed was constant, whatever the temperature: the volatilization rate for antimony was approximately 64%, while a approximately 36% fraction remained in the residual bottom ashes. But interestingly, while at 850 degrees C, antimony was mainly present in the gas-phase at a +III oxidation degree, an increase in temperature of 250 degrees C favoured the presence of antimony to its highest oxidation degree +V in the flue-gas stream, a valence known to be involved in less toxic species.

Impact of Enhanced Ozone Deposition and Halogen Chemistry on Tropospheric Ozone over the Northern Hemisphere.

PubMed

Sarwar, Golam; Gantt, Brett; Schwede, Donna; Foley, Kristen; Mathur, Rohit; Saiz-Lopez, Alfonso

2015-08-04

Fate of ozone in marine environments has been receiving increased attention due to the tightening of ambient air quality standards. The role of deposition and halogen chemistry is examined through incorporation of an enhanced ozone deposition algorithm and inclusion of halogen chemistry in a comprehensive atmospheric modeling system. The enhanced ozone deposition treatment accounts for the interaction of iodide in seawater with ozone and increases deposition velocities by 1 order of magnitude. Halogen chemistry includes detailed chemical reactions of organic and inorganic bromine and iodine species. Two different simulations are completed with the halogen chemistry: without and with photochemical reactions of higher iodine oxides. Enhanced deposition reduces mean summer-time surface ozone by ∼3% over marine regions in the Northern Hemisphere. Halogen chemistry without the photochemical reactions of higher iodine oxides reduces surface ozone by ∼15% whereas simulations with the photochemical reactions of higher iodine oxides indicate ozone reductions of ∼48%. The model without these processes overpredicts ozone compared to observations whereas the inclusion of these processes improves predictions. The inclusion of photochemical reactions for higher iodine oxides leads to ozone predictions that are lower than observations, underscoring the need for further refinement of the halogen emissions and chemistry scheme in the model.

GC-MS Study of Mono- and Bishaloethylphosphonates Related to Schedule 2.B.04 of the Chemical Weapons Convention: The Discovery of a New Intramolecular Halogen Transfer

NASA Astrophysics Data System (ADS)

Picazas-Márquez, Nerea; Sierra, María; Nova, Clara; Moreno, Juan Manuel; Aboitiz, Nuria; de Rivas, Gema; Sierra, Miguel A.; Martínez-Álvarez, Roberto; Gómez-Caballero, Esther

2016-09-01

A new class of compounds, mono- and bis-haloethylphosphonates (HAPs and bisHAPs, respectively), listed in Schedule 2.B.04 of the Chemical Weapons Convention (CWC), has been synthesized and studied by GC-MS with two aims. First, to improve the identification of this type of chemicals by the Organization for the Prohibition of Chemical Weapons, (OPCW). Second, to study the synergistic effect of halogen and silicon atoms in molecules undergoing mass spectrometry. Fragmentation patterns of trimethylsilyl derivatives of HAPs were found to depend on the nature of the halogen atom; this was in agreement with DFT-calculations. The data suggest that a novel intramolecular halogen transfer takes place during the fragmentation process.

GC-MS Study of Mono- and Bishaloethylphosphonates Related to Schedule 2.B.04 of the Chemical Weapons Convention: The Discovery of a New Intramolecular Halogen Transfer.

PubMed

Picazas-Márquez, Nerea; Sierra, María; Nova, Clara; Moreno, Juan Manuel; Aboitiz, Nuria; de Rivas, Gema; Sierra, Miguel A; Martínez-Álvarez, Roberto; Gómez-Caballero, Esther

2016-09-01

A new class of compounds, mono- and bis-haloethylphosphonates (HAPs and bisHAPs, respectively), listed in Schedule 2.B.04 of the Chemical Weapons Convention (CWC), has been synthesized and studied by GC-MS with two aims. First, to improve the identification of this type of chemicals by the Organization for the Prohibition of Chemical Weapons, (OPCW). Second, to study the synergistic effect of halogen and silicon atoms in molecules undergoing mass spectrometry. Fragmentation patterns of trimethylsilyl derivatives of HAPs were found to depend on the nature of the halogen atom; this was in agreement with DFT-calculations. The data suggest that a novel intramolecular halogen transfer takes place during the fragmentation process. Graphical Abstract ᅟ.

HYDRODEHALOGENATION OF 1- TO 3-CARBON HALOGENATED ORGANIC COMPOUNDS IN WATER USING A PALLADIUM CATALYST AND HYDROGEN GAS. (R825421)

EPA Science Inventory

Supported palladium (Pd) metal catalysts along with H₂ gas show
significant potential as a technology which can provide rapid, on-site
destruction of halogenated groundwater contaminants. Pd catalyzes the rapid
hydrodehalogenation of nine 1- to 3-carbon ...

75 FR 34673 - Approval of the Clean Air Act, Section 112(l), Authority for Hazardous Air Pollutants: Air...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-18

... Halogenated Solvent Cleaning Machines: State of Rhode Island Department of Environmental Management AGENCY... machines in Rhode Island, except for continuous web cleaning machines. This approval would grant RI DEM the... Halogenated Solvent NESHAP for organic solvent cleaning machines and would make the Rhode Island Department of...

Organohalogen pollutants in surface particulates from workshop floors of four major e-waste recycling sites in China and implications for emission lists.

PubMed

Zeng, Yan-Hong; Tang, Bin; Luo, Xiao-Jun; Zheng, Xiao-Bo; Peng, Ping-An; Mai, Bi-Xian

2016-11-01

To examine the environmental pollution associated with e-waste recycling activities, the concentrations of organohologenated pollutants (OHPs), i.e., short- and medium-chain chlorinated paraffins (SCCPs and MCCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and several other halogenated flame retardants (OHFRs), were investigated in surface particulates from the workshop floors of four major e-waste recycling sites (Taizhou, Guiyu, Dali and Qingyuan) in China. The mean levels of SCCPs, MCCPs, PCBs, PBDEs and OHFRs in surface particulates ranged from 30,000-61,000, 170,000-890,000, 2700-27,000, 52,000-240,000, and 62,000-140,000ng/g dry weight (dw), respectively. OHFRs, including decabromodiphenyl ethane, dechlorane plus, 1,2-bis(2,4,6-tribromophenoxy)ethane, tetrabromobisphenol A, hexabromocyclododecanes, polybrominated biphenyls, hexabromobenzene, pentabromotoluene, and pentabromoethylbenzene, were frequently (>50% detection frequency) detected in surface particulates with mean concentration ranges of 39,000-63,000, 310-2700, 98-16,000, 21,000-56,000, 55-5700, 1700-27,000, 42-1600, 3.2-220, and 5.8-12ng/g dw, respectively. The composition of OHPs varied depend on the e-waste items processing in different regions. Guiyu and Dali were typical sites contaminated by halogenated flame retardants (HFRs) and CPs, respectively, while Qingyuan, and Taizhou were representative PCB-polluted regions. The evidence produced by this preliminary study indicated that electronic devices and plastics may account for the high content of HFRs and the metal products are likely the major source of CPs in these e-waste sites. Copyright © 2016. Published by Elsevier B.V.

Real-time measurement and control of waste anesthetic gases during veterinary surgeries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burkhart, J.E.; Stobbe, T.J.

1990-12-01

Veterinary clinics are typically small businesses without access to sophisticated occupational safety and health programs that may exist for larger firms or hospitals. Exposures to waste anesthetic gases have been linked to a myriad of adverse health-related conditions. Excessive exposures to anesthetic agents are possible because many of the clinics use portable gas delivery carts that are not designed to capture waste gases. While scavenging systems are available to remove waste anesthetic gases, the cost may be prohibitive for smaller clinics and the effectiveness of these systems has not been fully established in veterinary clinics. The National Institute for Occupationalmore » Safety and Health (NIOSH) recommends limiting exposures to nitrous oxide (N2O) to a time-weighted average (TWA) concentration of 25 ppm and halogenated agents to 2 ppm. The NIOSH TWA is based on the weight of the agent collected from a 45-L air sample by charcoal adsorption over a sampling period not to exceed 1 hr. The NIOSH criteria state that, in most situations, control of N2O to the TWA as defined will result in levels of approximately 0.5 ppm of the halogenated agent. At present, no Occupational Safety and Health Administration (OSHA) permissible exposure level (PEL) exists for exposure to anesthetic agents; nor do specific recommendations exist for veterinary scavenging systems. Waste anesthetic gas exposures were determined using a modified MIRAN 1A at five veterinary clinics operating within the Morgantown, West Virginia, vicinity. For unscavenged systems of methoxyflurane and halothane, 1-hr time-weighted average exposures ranged from 0.5 to 45.5 ppm and 0.2 to 105.4 ppm, respectively.« less

Modeling the formation of TOCl, TOBr and TOI during chlor(am)ination of drinking water.

PubMed

Zhu, Xiaohu; Zhang, Xiangru

2016-06-01

The use of chlorine and chloramines in drinking water disinfection may produce innumerable halogenated disinfection byproducts (DBPs). Because of the impossibility of measuring the concentration and evaluating the toxicity of each individual halogenated DBP in a water sample, total organic halogen (TOX) as a collective parameter and a toxicity indicator for all the halogenated DBPs has been gaining popularity in recent years. TOX can be divided into total organic chlorine (TOCl), total organic bromine (TOBr), and total organic iodine (TOI). Previously, the authors' group studied the formation kinetics of TOCl and TOBr in chlor(am)ination using two models. In this study, we further explored the formation kinetics of TOI as well as TOCl and TOBr during chlor(am)ination by carefully selecting a series of iodine-related reactions and incorporating them into the two kinetic models. The models well predicted the levels of TOCl, TOBr, TOI, and total chlorine residual during chlorination and chloramination of simulated raw waters. According to the modeling results, 57.1-73.6% of the total generated iodinated DBPs in chlorination was converted to their chlorinated and brominated analogues by the substitution with hypochlorous acid and hypobromous acid; while in chloramination, with the presence of excessive monochloramine, the formed hypoiodous acid might react with monochloramine to form an iodine-substituted intermediate (proposed as chloroiodamine), which was responsible for 41.4-49.8% of the total generated iodinated DBPs, and meantime 51.9-52.6% of the total generated iodinated DBPs underwent deiodination via the base-catalyzed hydrolysis. The models were successfully applied in determining the lag time between the dosages of chlorine and ammonia, a challenging issue in chlorine-chloramine sequential treatment. This study provided important insights into kinetic reactions that control the formation of overall halogenated DBPs in chlor(am)ination. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of halogenated aromatics/aliphatics and nitrogen(N)-heterocyclic aromatics on estimating the persistence of future pharmaceutical compounds using a modified QSAR model.

PubMed

Lim, Seung Joo; Fox, Peter

2014-02-01

The effects of halogenated aromatics/aliphatics and nitrogen(N)-heterocyclic aromatics on estimating the persistence of future pharmaceutical compounds were investigated using a modified half life equation. The potential future pharmaceutical compounds investigated were approximately 2000 pharmaceutical drugs currently undergoing the United States Food and Drug Administration (US FDA) testing. EPI Suite (BIOWIN) model estimates the fates of compounds based on the biodegradability under aerobic conditions. While BIOWIN considered the biodegradability of a compound only, the half life equation used in this study was modified by biodegradability, sorption and cometabolic oxidation. It was possible that the potential future pharmaceutical compounds were more accurately estimated using the modified half life equation. The modified half life equation considered sorption and cometabolic oxidation of halogenated aromatic/aliphatics and nitrogen(N)-heterocyclic aromatics in the sub-surface, while EPI Suite (BIOWIN) did not. Halogenated aliphatics in chemicals were more persistent than halogenated aromatics in the sub-surface. In addition, in the sub-surface environment, the fates of organic chemicals were much more affected by halogenation in chemicals than by nitrogen(N)-heterocyclic aromatics. © 2013.

Halogenated 17ß-estradiol surrogates: synthesis, estrogenic activity, and initial investigations of fate in soil/water systems

USDA-ARS?s Scientific Manuscript database

17ß-Estradiol (E2) is a natural, endocrine-disrupting, steroid hormone excreted by all vertebrates that can enter the environment from domestic animal and wildlife wastes. Multiple field studies using food animal manures as E2 sources suggest significant background concentrations of E2 (e.g., wildli...

Observations and modeling of bromine induced mercury oxidation in the tropical free troposphere during TORERO

NASA Astrophysics Data System (ADS)

Coburn, Sean; Wang, Siyuan; terSchure, Arnout; Evans, Matt; Volkamer, Rainer

2013-04-01

The Tropical Ocean tRoposphere Exchange experiment TORERO (Jan/Feb 2012) probed air-sea exchange of very short lived halogens and organic carbon species over the full tropospheric air column above the eastern tropical Pacific Ocean. It is well known that halogens influence the oxidative capacity in the marine boundary layer, but their distribution and abundance is less clear in the tropical free troposphere, where most of tropospheric ozone mass resides, and about 80% of the global methane destruction occurs. The oxidation of elemental mercury (GEM) by halogens (i.e., bromine) further forms gaseous oxidized mercury (GOM), and this oxidation is accelerated at the low temperatures in the free troposphere compared to the boundary layer. Free tropospheric halogen radical abundances are thus of particular importance to understand the entry pathways for GOM deposition from the free troposphere to ecosystem, and the subsequent bio-accumulation of this neurotoxin. This presentation summarizes new observational evidence for halogen vertical distributions over the full tropospheric air column, and their abundance in the tropical troposphere, at mid-latitudes in the Northern and Southern hemisphere. BrO and IO were measured simultaneously by the CU Airborne MAX-DOAS instrument, and organic halogen precursors were measured by online GC-MS (TOGA) during 22 research flights aboard the NSF/NCAR GV aircraft. We employ atmospheric box modeling constrained by observations of gas-phase hydrocarbons, aerosols, photolysis frequencies, and meterological parameters measured aboard the plane to test the observed BrO and IO abundances, and evaluate the rate of GEM oxidation in light of recent updates about the stability of the Hg-Br adduct, and it's fate (Goodsite et al., 2012; Dibble et al., 2012). Finally, we compare our measurements with output from the GEOS-Chem model for selected case studies.

Effectiveness of Halogen-Based Disinfectants Against Acinetobacter Baumannii: Wound Care and Environmental Decontamination

DTIC Science & Technology

2006-11-01

EFFECTIVENESS OF HALOGEN-BASED DISINFECTANTS AGAINST Acinetobacter baumannii: WOUND CARE AND ENVIROMENTAL DECONTAMINATION James...a standard E. coli comparator, in a novel bacterial culture system that incorporated a three log range of organic growth media concentrations. We...report the highest dilutions of stock disinfectant able to inhibit replication or kill the bacteria , denoted as the maximum inhibitory dilution

Room-Temperature Phosphorescence in Pure Organic Materials: Halogen Bonding Switching Effects.

PubMed

Xiao, Lu; Wu, Yishi; Yu, Zhenyi; Xu, Zhenzhen; Li, Jinbiao; Liu, Yanping; Yao, Jiannian; Fu, Hongbing

2018-02-06

Organic room-temperature phosphorescence (ORTP), when combined with external stimuli-responsive capability, is very attractive for sensors and bio-imaging devices, but remains challenging. Herein, by doping two β-iminoenamine-BF 2 derivatives (S-2CN and S-2I) into a 4-iodoaniline (I-Ph-NH 2 ) crystalline matrix, the formation of S-2CN⋅⋅⋅I-Ph-NH 2 and S-2I⋅⋅⋅I-Ph-NH 2 halogen bonds leads to bright-red RTP emissions from these two host-guest doped crystals (hgDCs) with quantum efficiencies up to 13.43 % and 15.96 %, respectively. Upon treatment with HCl, the competition of I-Ph-NH 2 ⋅HCl formation against S-2I⋅⋅⋅I-Ph-NH 2 halogen bonding switches off the red RTP from S-2I/I-Ph-NH 2 hgDCs, whereas the stable halogen-bonded S-2CN⋅⋅⋅I-Ph-NH 2 ensures red RTP from S-2CN/I-Ph-NH 2 hgDCs remains unchanged. A security protection luminescence pattern by using these different HCl-responsive RTP behaviors was designed. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Post-synthetic halide conversion and selective halogen capture in hybrid perovskites† †Electronic supplementary information (ESI) available. CCDC 1048945–1048947. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5sc01135c

PubMed Central

Solis-Ibarra, D.; Smith, I. C.

2015-01-01

Reaction with halogen vapor allows us to post-synthetically exchange halides in both three- (3D) and two-dimensional (2D) organic–inorganic metal-halide perovskites. Films of 3D Pb–I perovskites cleanly convert to films of Pb–Br or Pb–Cl perovskites upon exposure to Br2 or Cl2 gas, respectively. This gas–solid reaction provides a simple method to produce the high-quality Pb–Br or Pb–Cl perovskite films required for optoelectronic applications. Reactivity with halogens can be extended to the organic layers in 2D metal-halide perovskites. Here, terminal alkene groups placed between the inorganic layers can capture Br2 gas through chemisorption to form dibromoalkanes. This reaction's selectivity for Br2 over I2 allows us to scrub Br2 to obtain high-purity I2 gas streams. We also observe unusual halogen transfer between the inorganic and organic layers within a single perovskite structure. Remarkably, the perovskite's crystallinity is retained during these massive structural rearrangements. PMID:29218171

Chemoselective Hydrodehalogenation of Organic Halides Utilizing Two-Dimensional Anionic Electrons of Inorganic Electride [Ca2N]+·e^.

PubMed

Kim, Ye Ji; Kim, Sun Min; Yu, Chunghyeon; Yoo, YoungMin; Cho, Eun Jin; Yang, Jung Woon; Kim, Sung Wng

2017-01-31

Halogenated organic compounds are important anthropogenic chemicals widely used in chemical industry, biology, and pharmacology; however, the persistence and inertness of organic halides cause human health problems and considerable environmental pollution. Thus, the elimination or replacement of halogen atoms with organic halides has been considered a central task in synthetic chemistry. In dehalogenation reactions, the consecutive single-electron transfer from reducing agents generates the radical and corresponding carbanion and thus removes the halogen atom as the leaving group. Herein, we report a new strategy for an efficient chemoselective hydrodehalogenation through the formation of stable carbanion intermediates, which are simply achieved by using highly mobile two-dimensional electrons of inorganic electride [Ca 2 N] + ·e - with effective electron transfer ability. The consecutive single-electron transfer from inorganic electride [Ca 2 N] + ·e - stabilized free carbanions, which is a key step in achieving the selective reaction. Furthermore, a determinant more important than leaving group ability is the stability control of free carbanions according to the s character determined by the backbone structure. We anticipate that this approach may provide new insight into selective chemical formation, including hydrodehalogenation.

Four groups of new aromatic halogenated disinfection byproducts: effect of bromide concentration on their formation and speciation in chlorinated drinking water.

PubMed

Pan, Yang; Zhang, Xiangru

2013-02-05

Bromide is naturally present in source waters worldwide. Chlorination of drinking water can generate a variety of chlorinated and brominated disinfection byproducts (DBPs). Although substantial efforts have been made to examine the effect of bromide concentration on the formation and speciation of halogenated DBPs, almost all previous studies have focused on trihalomethanes and haloacetic acids. Given that about 50% of total organic halogen formed in chlorination remains unknown, it is still unclear how bromide concentration affects the formation and speciation of the new/unknown halogenated DBPs. In this study, chlorinated drinking water samples with different bromide concentrations were prepared, and a novel approach-precursor ion scan using ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry-was adopted for the detection and identification of polar halogenated DBPs in these water samples. With this approach, 11 new putative aromatic halogenated DBPs were identified, and they were classified into four groups: dihalo-4-hydroxybenzaldehydes, dihalo-4-hydroxybenzoic acids, dihalo-salicylic acids, and trihalo-phenols. A mechanism for the formation of the four groups of new aromatic halogenated DBPs was proposed. It was found that increasing the bromide concentration shifted the entire polar halogenated DBPs as well as the four groups of new DBPs from being less brominated to being more brominated; these new aromatic halogenated DBPs might be important intermediate DBPs formed in drinking water chlorination. Moreover, the speciation of the four groups of new DBPs was modeled: the speciation patterns of the four groups of new DBPs well matched those determined from the model equations, and the reactivity differences between HOBr and HOCl in reactions forming the four groups of new DBPs were larger than those in reactions forming trihalomethanes and haloacetic acids.

Health risk characterization for resident inhalation exposure to particle-bound halogenated flame retardants in a typical e-waste recycling zone.

PubMed

Luo, Pei; Bao, Lian-Jun; Wu, Feng-Chang; Li, Shao-Meng; Zeng, Eddy Y

2014-01-01

Inhalation of pollutants is an important exposure route for causing human health hazards, and inhalation exposure assessment must take into account particle size distribution because particle-bound pollutants are size-dependent. Such information is scarce, particularly for residents dwelling within e-waste recycling zones where abundant atmospheric halogenated flame retardants (HFRs) commonly used in electronic/electrical devices have been widely reported. Atmospheric size-fractioned particle samples were collected using a 10-stage Micro-Orifice Uniform Deposit Impactor from an e-waste recycling zone in South China. The deposition efficiencies and fluxes of size-fractioned HFRs including polybrominated diphenyl ethers (PBDEs), alternative brominated flame retardants, and Dechlorane Plus in the human respiratory tract were estimated using the International Commission on Radiological Protection deposition model. The majority of HFRs was found to deposit in the head airways, with coarse particles (aerodynamic diameter (Dp) > 1.8 μm) contributing the most (69-91%). Conversely, fine particles (Dp < 1.8 μm) were dominant in the alveolar region (62-80%). The inhalation intake of PBDEs within the e-waste recycling zone was 44 ng/d (95% confidence interval (CI): 30-65 ng/d), close to those through food consumption in non-e-waste recycling regions. The estimated total hazard quotient of particle-bound HFRs was 5.6 × 10(-4) (95% CI: 3.8 × 10(-4)-8.8 × 10(-4)). In addition, incremental lifetime cancer risk induced by BDE-209 was 1.36 × 10(-10) (95% CI: 7.3 × 10(-11)-2.3 × 10(-10)), much lower than the Safe Acceptable Range (1.0 × 10(-6)-1.0 × 10(-4)) established by the United States Environmental Protection Agency. These results indicate that the potential health risk from inhalation exposure to particle-bound HFRs for residents dwelling in the e-waste recycling zone was low.

Remediation of electronic waste polluted soil using a combination of persulfate oxidation and chemical washing.

PubMed

Chen, Fu; Luo, Zhanbin; Liu, Gangjun; Yang, Yongjun; Zhang, Shaoliang; Ma, Jing

2017-12-15

Laboratory experiments were conducted to investigate the efficiency of a simultaneous chemical extraction and oxidation for removing persistent organic pollutants (POPs) and toxic metals from an actual soil polluted by the recycling activity of electronic waste. Various chemicals, including hydroxypropyl-β-cyclodextrin (HPCD), citric acid (CA) and sodium persulfate (SP) were applied synchronously with Fe 2+ activated oxidation to enhance the co-removal of both types of pollutants. It is found that the addition of HPCD can enhance POPs removal through solubilization of POPs and iron chelation; while the CA-chelated Fe 2+ activation process is effective for extracting metals and degrading residual POPs. Under the optimized reagent conditions, 69.4% Cu, 78.1% Pb, 74.6% Ni, 97.1% polychlorinated biphenyls, 93.8% polycyclic aromatic hydrocarbons, and 96.4% polybrominated diphenylethers were removed after the sequential application of SP-HPCD-Fe 2+ and SP-CA-Fe 2+ processes with a duration of 180 and 240 min, respectively. A high dehalogenation efficiency (84.8% bromine and 86.2% chlorine) is observed, suggesting the low accumulation of halogen-containing organic intermediates. The remediated soil can satisfy the national soil quality standard of China. Collectively, co-contaminated soil can be remediated with reasonable time and capital costs through simultaneous application of persulfate oxidation and chemical extraction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distributions and compositions of old and emerging flame retardants in the rhizosphere and non-rhizosphere soil in an e-waste contaminated area of South China.

PubMed

Wang, Shaorui; Wang, Yan; Song, Mengke; Luo, Chunling; Li, Jun; Zhang, Gan

2016-01-01

We investigated rhizosphere effects on the distributions and compositions of polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and dechlorane plus (DPs) in rhizosphere soils (RS) and non-rhizosphere soils (NRS) in an e-waste recycling area in South China. The concentrations of PBDEs, NBFRs, and DPs ranged from 13.9 to 351, 11.6 to 70.8, and 0.64 to 8.74 ng g(-1) in RS and 7.56 to 127, 8.98 to 144, and 0.38 to 8.45 ng g(-1) in NRS, respectively. BDE-209 and DBDPE were the dominant congeners of PBDEs and NBFRs, respectively. PBDEs, NBFRs, and DPs were more enriched in RS than NRS in most vegetables species. Further analysis suggested that the differentiation of the rhizosphere effect on halogenated flame retardants (HFRs) was not solely controlled by the octanol-water coefficients. This difference was also reflected by the correlations between total organic carbon (TOC) and PBDEs, NBFRs, or DPs, which indicated that organic carbon was a more pivotal controlling factor for PBDEs and DPs than for NBFRs in soil. We also found significant positive correlations between PBDEs and their replacement products, which indicated a similar emission pattern and environmental behaviour. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of halogenated impurities on lifetime of organic light emitting diode

NASA Astrophysics Data System (ADS)

Yamawaki, Hayato; Suzuki, Kunihiko; Kubota, Tomohiro; Watabe, Takeyoshi; Ishigaki, Ayumi; Nakamura, Rina; Inoue, Hideko; Nakashima, Harue; Horikoshi, Nozomi; Nowatari, Hiromi; Kataishi, Riho; Hamada, Toshiki; Sasaki, Toshiki; Suzuki, Tsunenori; Seo, Satoshi

2016-09-01

We investigated a correlation between lifetime and the halogen element concentration in an organic light-emitting diode (OLED) and conducted experiments and simulations to discuss degradation mechanisms due to the halogen. OELD is generally formed of high-purity materials. Since the synthesis of high-purity materials takes time and cost, quantitative understanding of the kind, amount, and influence of impurities in OLED devices is expected. The results of combustion ion chromatography show that, if the chlorine concentration in the host material is more than several parts per million, the lifetime of the device is drastically reduced. The chlorine element, which is derived from the chlorinated by-product of the host material, is found to be transferred from the chloride to other materials (e.g., an emissive dopant) according to the results of LC-MS analysis. In addition, the electron transport layer including such impurities is also found to adversely affect the lifetime. The results of TOF-SIMS analysis suggest that the dissociated chlorine element diffuse to the light-emitting layer side when the device is driven. The results of simulations (Gaussian 09) and electrochemical analyses (cyclic voltammetry and electrolysis) reveal that the halogen element is easy to dissociate from halide by excitation or reduction. The halogen element can repeat reactions with the peripheral materials by excitation or reduction and cause damages, e.g., generate radicals or further reaction products due to the radicals. The results of simulation suggest that, such compounds have low energy level and become quenchers.

DFT +U Modeling of Hole Polarons in Organic Lead Halide Perovskites

NASA Astrophysics Data System (ADS)

Welch, Eric; Erhart, Paul; Scolfaro, Luisa; Zakhidov, Alex

Due to the ever present drive towards improved efficiencies in solar cell technology, new and improved materials are emerging rapidly. Organic halide perovskites are a promising prospect, yet a fundamental understanding of the organic perovskite structure and electronic properties is missing. Particularly, explanations of certain physical phenomena, specifically a low recombination rate and high mobility of charge carriers still remain controversial. We theoretically investigate possible formation of hole polarons adopting methodology used for oxide perovskites. The perovskite studied here is the ABX3structure, with A being an organic cation, B lead and C a halogen; the combinations studied allow for A1,xA2 , 1 - xBX1,xX2 , 3 - xwhere the alloy convention is used to show mixtures of the organic cations and/or the halogens. Two organic cations, methylammonium and formamidinium, and three halogens, iodine, chlorine and bromine are studied. Electronic structures and polaron behavior is studied through first principle density functional theory (DFT) calculations using the Vienna Ab Initio Simulation Package (VASP). Local density approximation (LDA) pseudopotentials are used and a +U Hubbard correction of 8 eV is added; this method was shown to work with oxide perovskites. It is shown that a localized state is realized with the Hubbard correction in systems with an electron removed, residing in the band gap of each different structure. Thus, hole polarons are expected to be seen in these perovskites.

Fluorescence spectroscopy for monitoring reduction of natural organic matter and halogenated furanone precursors by biofiltration.

PubMed

Peleato, Nicolás M; McKie, Michael; Taylor-Edmonds, Lizbeth; Andrews, Susan A; Legge, Raymond L; Andrews, Robert C

2016-06-01

The application of fluorescence spectroscopy to monitor natural organic matter (NOM) reduction as a function of biofiltration performance was investigated. This study was conducted at pilot-scale where a conventional media filter was compared to six biofilters employing varying enhancement strategies. Overall reductions of NOM were identified by measuring dissolved organic carbon (DOC), and UV absorbance at 254 nm, as well as characterization of organic sub-fractions by liquid chromatography-organic carbon detection (LC-OCD) and parallel factors analysis (PARAFAC) of fluorescence excitation-emission matrices (FEEM). The biofilter using granular activated carbon media, with exhausted absorptive capacity, was found to provide the highest removal of all identified PARAFAC components. A microbial or processed humic-like component was found to be most amenable to biodegradation by biofilters and removal by conventional treatment. One refractory humic-like component, detectable only by FEEM-PARAFAC, was not well removed by biofiltration or conventional treatment. All biofilters removed protein-like material to a high degree relative to conventional treatment. The formation potential of two halogenated furanones, 3-chloro-4(dichloromethyl)-2(5H)-furanone (MX) and mucochloric acid (MCA), as well as overall treated water genotoxicity are also reported. Using the organic characterization results possible halogenated furanone and genotoxicity precursors are identified. Comparison of FEEM-PARAFAC and LC-OCD results revealed polysaccharides as potential MX/MCA precursors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of halogenated DBPs and identification of new DBPs trihalomethanols in chlorine dioxide treated drinking water with multiple extractions.

PubMed

Han, Jiarui; Zhang, Xiangru; Liu, Jiaqi; Zhu, Xiaohu; Gong, Tingting

2017-08-01

Chlorine dioxide (ClO 2 ) is a widely used alternative disinfectant due to its high biocidal efficiency and low-level formation of trihalomethanes and haloacetic acids. A major portion of total organic halogen (TOX), a collective parameter for all halogenated DBPs, formed in ClO 2 -treated drinking water is still unknown. A commonly used pretreatment method for analyzing halogenated DBPs in drinking water is one-time liquid-liquid extraction (LLE), which may lead to a substantial loss of DBPs prior to analysis. In this study, characterization and identification of polar halogenated DBPs in a ClO 2 -treated drinking water sample were conducted by pretreating the sample with multiple extractions. Compared to one-time LLE, the combined four-time LLEs improved the recovery of TOX by 2.3 times. The developmental toxicity of the drinking water sample pretreated with the combined four-time LLEs was 1.67 times higher than that pretreated with one-time LLE. With the aid of ultra-performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, a new group of polar halogenated DBPs, trihalomethanols, were detected in the drinking water sample pretreated with multiple extractions; two of them, trichloromethanol and bromodichloromethanol, were identified with synthesized standard compounds. Moreover, these trihalomethanols were found to be the transformation products of trihalomethanes formed during ClO 2 disinfection. The results indicate that multiple LLEs can significantly improve extraction efficiencies of polar halogenated DBPs and is a better pretreatment method for characterizing and identifying new polar halogenated DBPs in drinking water. Copyright © 2017. Published by Elsevier B.V.

Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer-chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS).

PubMed

Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A; Schimmelmann, Arndt

2017-03-30

Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H 2 ) is responsible for non-quantitative H 2 yields and possible hydrogen isotopic fractionation. Our previously introduced, new chromium-based EA-Cr/HTC-IRMS (Elemental Analyzer-Chromium/High-Temperature Conversion Isotope Ratio Mass Spectrometry) technique focused primarily on nitrogen-bearing compounds. Several technical and analytical issues concerning halogen- and sulfur-bearing samples, however, remained unresolved and required further refinement of the reactor systems. The EA-Cr/HTC reactor was substantially modified for the conversion of halogen- and sulfur-bearing samples. The performance of the novel conversion setup for solid and liquid samples was monitored and optimized using a simultaneously operating dual-detection system of IRMS and ion trap MS. The method with several variants in the reactor, including the addition of manganese metal chips, was evaluated in three laboratories using EA-Cr/HTC-IRMS (on-line method) and compared with traditional uranium-reduction-based conversion combined with manual dual-inlet IRMS analysis (off-line method) in one laboratory. The modified EA-Cr/HTC reactor setup showed an overall H 2 -recovery of more than 96% for all halogen- and sulfur-bearing organic compounds. All results were successfully normalized via two-point calibration with VSMOW-SLAP reference waters. Precise and accurate hydrogen isotopic analysis was achieved for a variety of organics containing F-, Cl-, Br-, I-, and S-bearing heteroelements. The robust nature of the on-line EA-Cr/HTC technique was demonstrated by a series of 196 consecutive measurements with a single reactor filling. The optimized EA-Cr/HTC reactor design can be implemented in existing analytical equipment using commercially available material and is universally applicable for both heteroelement-bearing and heteroelement-free organic-compound classes. The sensitivity and simplicity of the on-line EA-Cr/HTC-IRMS technique provide a much needed tool for routine hydrogen-isotope source tracing of organic contaminants in the environment. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Volatile organic compound sensor system

DOEpatents

Schabron, John F [Laramie, WY; Rovani, Jr., Joseph F.; Bomstad, Theresa M [Laramie, WY; Sorini-Wong, Susan S [Laramie, WY

2009-02-10

Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

Volatile organic compound sensor system

DOEpatents

Schabron, John F.; Rovani, Jr., Joseph F.; Bomstad, Theresa M.; Sorini-Wong, Susan S.; Wong, Gregory K.

2011-03-01

Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

Analysis of Organohalogen Products From Chlorination of Natural Waters Under Simulated Biofouling Control Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bean, R. M.; Mann, D. C.; Riley, R. G.

1980-06-01

The products of low-level chlorination of natural waters from ten locations across the continental United States have been studied, with emphasis on volatile and lipophilic organohalogen components. A specially designed apparatus permitted continuous sampling and chlorination of water in a manner analogous to some types of cooling water treatments. Volatile components were analyzed using headspace, purge-and-trap, and resin adsorption methods. The less-volatile components were collected by passing large volumes of the chlorinated water over XAD-2 columns. Total organic halogen collected on XAD resins was compared with the halogen contribution of haloform compounds. The XAD samples were further separated into fractionsmore » according to molecular weight and polarity using liquid chrOmatography. These studies indicate that haloforms are the most abundant lipophilic halogenated products formed from low-level chlorination of natural waters, but that other halogenated lipophilic material is also formed.« less

Engineering a Catabolic Pathway in Plants for the Degradation of 1,2-Dichloroethane1[OA

PubMed Central

Mena-Benitez, Gilda L.; Gandia-Herrero, Fernando; Graham, Stuart; Larson, Tony R.; McQueen-Mason, Simon J.; French, Christopher E.; Rylott, Elizabeth L.; Bruce, Neil C.

2008-01-01

Plants are increasingly being employed to clean up environmental pollutants such as heavy metals; however, a major limitation of phytoremediation is the inability of plants to mineralize most organic pollutants. A key component of organic pollutants is halogenated aliphatic compounds that include 1,2-dichloroethane (1,2-DCA). Although plants lack the enzymatic activity required to metabolize this compound, two bacterial enzymes, haloalkane dehalogenase (DhlA) and haloacid dehalogenase (DhlB) from the bacterium Xanthobacter autotrophicus GJ10, have the ability to dehalogenate a range of halogenated aliphatics, including 1,2-DCA. We have engineered the dhlA and dhlB genes into tobacco (Nicotiana tabacum ‘Xanthi’) plants and used 1,2-DCA as a model substrate to demonstrate the ability of the transgenic tobacco to remediate a range of halogenated, aliphatic hydrocarbons. DhlA converts 1,2-DCA to 2-chloroethanol, which is then metabolized to the phytotoxic 2-chloroacetaldehyde, then chloroacetic acid, by endogenous plant alcohol dehydrogenase and aldehyde dehydrogenase activities, respectively. Chloroacetic acid is dehalogenated by DhlB to produce the glyoxylate cycle intermediate glycolate. Plants expressing only DhlA produced phytotoxic levels of chlorinated intermediates and died, while plants expressing DhlA together with DhlB thrived at levels of 1,2-DCA that were toxic to DhlA-expressing plants. This represents a significant advance in the development of a low-cost phytoremediation approach toward the clean-up of halogenated organic pollutants from contaminated soil and groundwater. PMID:18467461

VOCs elimination and health risk reduction in e-waste dismantling workshop using integrated techniques of electrostatic precipitation with advanced oxidation technologies.

PubMed

Chen, Jiangyao; Huang, Yong; Li, Guiying; An, Taicheng; Hu, Yunkun; Li, Yunlu

2016-01-25

Volatile organic compounds (VOCs) emitted during the electronic waste dismantling process (EWDP) were treated at a pilot scale, using integrated electrostatic precipitation (EP)-advanced oxidation technologies (AOTs, subsequent photocatalysis (PC) and ozonation). Although no obvious alteration was seen in VOC concentration and composition, EP technology removed 47.2% of total suspended particles, greatly reducing the negative effect of particles on subsequent AOTs. After the AOT treatment, average removal efficiencies of 95.7%, 95.4%, 87.4%, and 97.5% were achieved for aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, as well as nitrogen- and oxygen-containing compounds, respectively, over 60-day treatment period. Furthermore, high elimination capacities were also seen using hybrid technique of PC with ozonation; this was due to the PC unit's high loading rates and excellent pre-treatment abilities, and the ozonation unit's high elimination capacity. In addition, the non-cancer and cancer risks, as well as the occupational exposure cancer risk, for workers exposed to emitted VOCs in workshop were reduced dramatically after the integrated technique treatment. Results demonstrated that the integrated technique led to highly efficient and stable VOC removal from EWDP emissions at a pilot scale. This study points to an efficient approach for atmospheric purification and improving human health in e-waste recycling regions. Copyright © 2015 Elsevier B.V. All rights reserved.

Surrogate Indicators of Radionuclide Migration at the Amargosa Desert Research Site, Nye County, Nevada

NASA Astrophysics Data System (ADS)

Stonestrom, D. A.; Andraski, B. J.; Baker, R. J.; Luo, W.; Michel, R. L.

2005-05-01

Contaminant-transport processes are being investigated at the U.S. Geological Survey's Amargosa Desert Research Site (ADRS), adjacent to the Nation's first commercial disposal facility for low-level radioactive waste. Gases containing tritium and radiocarbon are migrating through a 110-m thick unsaturated zone from unlined trenches that received waste from 1962 to 1992. Information on plume dynamics comes from an array of shallow (<2 m) and two vertical arrays of deep (5-109 m) gas-sampling ports, plus ground-water monitoring wells. Migration is dominated by lateral transport in the upper 50 m of sediments. Radiological analyses require ex-situ wet-chemical techniques, because in-situ sensors for the radionuclides of interest do not exist. As at other LLRW-disposal facilities, radionuclides at the ADRS are mixed with varying amounts of volatile organic compounds (VOCs) and other substances. Halogenated-methanes, -ethanes, and -ethenes dominate the complex mixture of VOCs migrating from the disposal area. These compounds and their degradates provide a distinctive "fingerprint" of contamination originating from low-level radioactive waste. Carbon-dioxide and VOC anomalies provide indicator proxies for radionuclide contamination. Spatial and temporal patterns of co-disposed and byproduct constituents provide field-scale information about physical and biochemical processes involved in transport. Processes include reduction and biorespiration within trenches, and largely non-reactive, barometrically dispersed diffusion away from trenches.

Halogenated methyl-phenyl ethers (anisoles) in the environment: determination of vapor pressures, aqueous solubilities, Henry's law constants, and gas/water- (Kgw), n-octanol/water- (Kow) and gas/n-octanol (Kgo) partition coefficients.

PubMed

Pfeifer, O; Lohmann, U; Ballschmiter, K

2001-11-01

Halogenated methyl-phenyl ethers (methoxybenzenes, anisoles) are ubiquitous organics in the environment although they are not produced in industrial quantities. Modelling the fate of organic pollutants such as halogenated anisoles requires a knowledge of the fundamental physico-chemical properties of these compounds. The isomer-specific separation and detection of 60 of the 134 possible congeners allowing an environmental fingerprinting are reported in this study. The vapor pressure p0(L) of more than 60 and further physico-chemical properties of 26 available congeners are given. Vapor pressures p0(L), water solubilities S(L)W, and n-octanol/water partition coefficients Kow were determined by capillary HR-GC (High Resolution Gas Chromatography) on a non-polar phase and by RP-HPLC (Reversed Phase High Performance Liquid Chromatography) on a C18 phase with chlorobenzenes as reference standards. From these experimental data the Henry's law constants H, and the gas/water Kgw and gas/n-octanol Kgo partition coefficients were calculated. We found that vapor pressures, water solubilities, and n-octanol/water partition coefficients of the halogenated anisoles are close to those of the chlorobenzenes. A similar environmental fate of both groups can, therefore, be predicted.

Halogenated flame retardants in home-produced eggs from an electronic waste recycling region in South China: levels, composition profiles, and human dietary exposure assessment.

PubMed

Zheng, Xiao-Bo; Wu, Jiang-Ping; Luo, Xiao-Jun; Zeng, Yan-Hong; She, Ya-Zhe; Mai, Bi-Xian

2012-09-15

Three regulated halogenated flame retardants (HFRs), i.e., polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and hexabromocyclododecanes (HBCDs), and several alternative HFRs (AHFRs) including Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), were investigated in the home-produced eggs from three recycling sites and a reference site in an electronic waste (e-waste) recycling region, South China. Mean levels of HFRs in eggs from the recycling sites ranged 2640-14100, 700-1620, 44-350, and 720-3920 ng/g lipid weight for ∑PBDEs, ∑PBBs, ∑HBCDs, and ∑AHFRs, respectively, which were one to two orders of magnitude higher than those examined in the reference site. PBDEs were the predominant HFR in those eggs, with contributions >50% to the total HFRs; followed by PBBs and the AHFRs (contributing 14-22% in average). The α-HBCD was the predominant diastereoisomers of HBCDs, with preferential enrichment of the (-)-enantiomer in most of the eggs; but no significant stereoselective enrichment of the DP isomers was observed in these eggs. The average estimated daily intakes (EDIs) of PBDEs, PBBs, HBCDs, and the AHFRs via eggs from the recycling sites ranged 4200-20000, 1120-2440, 80-490, and 970-4530 ng/day, respectively, which were one to two orders of magnitude higher than those reported from other parts of the world. The potential adverse effects of these HFRs to human health in the e-waste sites should be further investigated. This is the first report on the isomer compositions of DP and the chiral signatures of HBCDs in hen eggs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of halide ions on photodegradation of sulfonamide antibiotics: Formation of halogenated intermediates.

PubMed

Li, Yingjie; Qiao, Xianliang; Zhang, Ya-Nan; Zhou, Chengzhi; Xie, Huaijun; Chen, Jingwen

2016-10-01

The occurrence of sulfonamide antibiotics (SAs) in estuarine waters urges insights into their environmental fate for ecological risk assessment. Although many studies focused on the photochemical behavior of SAs, yet the effects of halide ions relevant to estuarine and marine environments on their photodegradation have been poorly understood. Here, we investigated the effects of halide ions on the photodegradation of SAs with sulfapyridine, sulfamethazine, and sulfamethoxazole as representative compounds. Results showed that halide ions did not significantly impact the photodegradation of sulfapyridine and sulfamethoxazole, while they significantly promoted the photodegradation of sulfamethazine. Further experiments found that ionic strength applied with NaClO4 significantly enhanced the photodegradation of the SAs, which was attributed to the decreased quenching rate constant of the triplet-excited SAs ((3)SA(∗)). Compared with ionic strength, specific Cl(-) effects retarded the photodegradation of the SAs. Our study found that triplet-excited sulfamethazine can oxidize halide ions to produce halogen radicals, subsequently leading to the halogenation of sulfamethazine, which was confirmed by the identification of both chlorinated and brominated intermediates. These results indicate that halide ions play an important role in the photochemical behavior of some SAs in estuarine waters and seawater. The occurrence of halogenation for certain organic pollutants can be predicted by comparing the oxidation potentials of triplet-excited contaminants with those of halogen radicals. Our findings are helpful in understanding the photochemical behavior and assessing the ecological risks of SAs and other organic pollutants in estuarine and marine environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Low-Level detections of halogenated volatile organic compounds in groundwater: Use in vulnerability assessments

USGS Publications Warehouse

Plummer, Niel; Busenberg, E.; Eberts, S.M.; Bexfield, L.M.; Brown, C.J.; Fahlquist, L.S.; Katz, B.G.; Landon, M.K.

2008-01-01

Concentrations of halogenated volatile organic compounds (VOCs) were determined by gas chromatography (GC) with an electron-capture detector (GC-ECD) and by gas chromatography with mass spectrometry (GC-MS) in 109 groundwater samples from five study areas in the United States. In each case, the untreated water sample was used for drinking-water purposes or was from a monitoring well in an area near a drinking-water source. The minimum detection levels (MDLs) for 25 VOCs that were identified in GC-ECD chromatograms, typically, were two to more than four orders of magnitude below the GC-MS MDLs. At least six halogenated VOCs were detected in all of the water samples analyzed by GC-ECD, although one or more VOCs were detected in only 43% of the water samples analyzed by GC-MS. In nearly all of the samples, VOC concentrations were very low and presented no known health risk. Most of the low-level VOC detections indicated post-1940s recharge, or mixtures of recharge that contained a fraction of post-1940s water. Concentrations of selected halogenated VOCs in groundwater from natural and anthropogenic atmospheric sources were estimated and used to recognize water samples that are being impacted by nonatmospheric sources. A classification is presented to perform vulnerability assessments at the scale of individual wells using the number of halogenated VOC detections and total dissolved VOC concentrations in samples of untreated drinking water. The low-level VOC detections are useful in vulnerability assessments, particularly for samples in which no VOCs are detected by GC-MS analysis.

Small-Molecule Organic Photovoltaic Modules Fabricated via Halogen-Free Solvent System with Roll-to-Roll Compatible Scalable Printing Method.

PubMed

Heo, Youn-Jung; Jung, Yen-Sook; Hwang, Kyeongil; Kim, Jueng-Eun; Yeo, Jun-Seok; Lee, Sehyun; Jeon, Ye-Jin; Lee, Donmin; Kim, Dong-Yu

2017-11-15

For the first time, the photovoltaic modules composed of small molecule were successfully fabricated by using roll-to-roll compatible printing techniques. In this study, blend films of small molecules, BTR and PC 71 BM were slot-die coated using a halogen-free solvent system. As a result, high efficiencies of 7.46% and 6.56% were achieved from time-consuming solvent vapor annealing (SVA) treatment and roll-to-roll compatible solvent additive approaches, respectively. After successful verification of our roll-to-roll compatible method on small-area devices, we further fabricated large-area photovoltaic modules with a total active area of 10 cm 2 , achieving a power conversion efficiency (PCE) of 4.83%. This demonstration of large-area photovoltaic modules through roll-to-roll compatible printing methods, even based on a halogen-free solvent, suggests the great potential for the industrial-scale production of organic solar cells (OSCs).

Quantum Chemical Examination of the Sequential Halogen Incorporation Scheme for the Modeling of Speciation of I/Br/Cl-Containing Trihalomethanes.

PubMed

Zhang, Chenyang; Li, Maodong; Han, Xuze; Yan, Mingquan

2018-02-20

The recently developed three-step ternary halogenation model interprets the incorporation of chlorine, bromine, and iodine ions into natural organic matter (NOM) and formation of iodine-, bromine-, and chlorine-containing trihalomethanes (THMs) based on the competition of iodine, bromine, and chlorine species at each node of the halogenation sequence. This competition is accounted for using the dimensionless ratios (denoted as γ) of kinetic rates of reactions of the initial attack sites or halogenated intermediates with chlorine, bromine, and iodine ions. However, correlations between the model predictions made and mechanistic aspects of the incorporation of halogen species need to be ascertained in more detail. In this study, quantum chemistry calculations were first used to probe the formation mechanism of 10 species of Cl-/Br-/I- THMs. The HOMO energy (E HOMO ) of each mono-, bi-, or trihalomethanes were calculated by B3LYP method in Gaussian 09 software. Linear correlations were found to exist between the logarithms of experimentally determined kinetic preference coefficients γ reported in prior research and, on the other hand, differences of E HOMO values between brominated/iodinated and chlorinated halomethanes. One notable exception from this trend was that observed for the incorporation of iodine into mono- and di-iodinated intermediates. These observations confirm the three-step halogen incorporation sequence and the factor γ in the statistical model. The combined use of quantum chemistry calculations and the ternary sequential halogenation model provides a new insight into the microscopic nature of NOM-halogen interactions and the trends seen in the behavior of γ factors incorporated in the THM speciation models.

Electrochemical oxidation of tramadol in low-salinity reverse osmosis concentrates using boron-doped diamond anodes.

PubMed

Lütke Eversloh, Christian; Schulz, Manoj; Wagner, Manfred; Ternes, Thomas A

2015-04-01

The electrochemical treatment of low-salinity reverse osmosis (RO) concentrates was investigated using tramadol (100 μM) as a model substance for persistent organic contaminants. Galvanostatic degradation experiments using boron-doped diamond electrodes at different applied currents were conducted in RO concentrates as well as in ultra-pure water containing either sodium chloride or sodium sulfate. Kinetic investigations revealed a significant influence of in-situ generated active chlorine besides direct anodic oxidation. Therefore, tramadol concentrations decreased more rapidly at elevated chloride content. Nevertheless, reduction of total organic carbon (TOC) was found to be comparatively low, demonstrating that transformation rather than mineralization was taking place. Early stage product formation could be attributed to both direct and indirect processes, including demethylation, hydroxylation, dehydration, oxidative aromatic ring cleavage and halogenation reactions. The latter led to various halogenated derivatives and resulted in AOX (adsorbable organic halogens) formation in the lower mg/L-range depending on the treatment conditions. Characterisation of transformation products (TPs) was achieved via MS(n) experiments and additional NMR measurements. Based on identification and quantification of the main TPs in different matrices and on additional potentiostatic electrolysis, a transformation pathway was proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

THE DETERMINATION OF TOTAL ORGANIC HALIDE IN WATER: A COMPARATIVE STUDY OF TWO INSTRUMENTS

EPA Science Inventory

Total organic halide (TOX) analyzers are commonly used to measure the amount of dissolved halogenated organic byproducts in disinfected waters. ecause of the lack of information on the identity of disinfection byproducts, rigorous testing of the dissolved organic halide (DOX) pro...

Halogenation of Hydraulic Fracturing Additives in the Shale Well Parameter Space

NASA Astrophysics Data System (ADS)

Sumner, A. J.; Plata, D.

2017-12-01

Horizontal Drilling and Hydraulic fracturing (HDHF) involves the deep-well injection of a `fracking fluid' composed of diverse and numerous chemical additives designed to facilitate the release and collection of natural gas from shale plays. The potential impacts of HDHF operations on water resources and ecosystems are numerous, and analyses of flowback samples revealed organic compounds from both geogenic and anthropogenic sources. Furthermore, halogenated chemicals were also detected, and these compounds are rarely disclosed, suggesting the in situ halogenation of reactive additives. To test this transformation hypothesis, we designed and operated a novel high pressure and temperature reactor system to simulate the shale well parameter space and investigate the chemical reactivity of twelve commonly disclosed and functionally diverse HDHF additives. Early results revealed an unanticipated halogenation pathway of α-β unsaturated aldehyde, Cinnamaldehyde, in the presence of oxidant and concentrated brine. Ongoing experiments over a range of parameters informed a proposed mechanism, demonstrating the role of various shale-well specific parameters in enabling the demonstrated halogenation pathway. Ultimately, these results will inform a host of potentially unintended interactions of HDHF additives during the extreme conditions down-bore of a shale well during HDHF activities.

THE DETERMINATION OF TOTAL ORGANIC HALIDE IN WATER: AN INTERLABORATORY COMPARATIVE STUDY OF TWO METHODS

EPA Science Inventory

Total organic halide (TOX) analyzers are commonly used to measure the amount of dissolved halogenated organic byproducts in disinfected waters. Because of the lack of information on the identity of disinfection byproducts, rigorous testing of the dissolved organic halide (DOX) pr...

Exploring the Chemistry and Biology of Vanadium-dependent Haloperoxidases*

PubMed Central

Winter, Jaclyn M.; Moore, Bradley S.

2009-01-01

Nature has developed an exquisite array of methods to introduce halogen atoms into organic compounds. Most of these enzymes are oxidative and require either hydrogen peroxide or molecular oxygen as a cosubstrate to generate a reactive halogen atom for catalysis. Vanadium-dependent haloperoxidases contain a vanadate prosthetic group and utilize hydrogen peroxide to oxidize a halide ion into a reactive electrophilic intermediate. These metalloenzymes have a large distribution in nature, where they are present in macroalgae, fungi, and bacteria, but have been exclusively characterized in eukaryotes. In this minireview, we highlight the chemistry and biology of vanadium-dependent haloperoxidases from fungi and marine algae and the emergence of new bacterial members that extend the biological function of these poorly understood halogenating enzymes. PMID:19363038

Halogenated volatile organic compounds in chlorine-bleach-containing household products and implications for their use

NASA Astrophysics Data System (ADS)

Odabasi, Mustafa; Elbir, Tolga; Dumanoglu, Yetkin; Sofuoglu, Sait C.

2014-08-01

It was recently shown that substantial amounts of halogenated volatile organic compounds (VOCs) are formed in chlorine-bleach-containing household products as a result of reactions of sodium hypochlorite with organic product components. Use of these household products results in elevated indoor air halogenated VOC concentrations. Halogenated VOCs in several chlorine-bleach-containing household products (plain, n = 9; fragranced, n = 4; and surfactant-added, n = 29) from Europe and North America were measured in the present study. Chloroform and carbon tetrachloride were the dominating compounds having average concentrations of 9.5 ± 29.0 (average ± SD) and 23.2 ± 44.3 (average ± SD) mg L-1, respectively. Halogenated VOC concentrations were the lowest in plain bleach, slightly higher in fragranced products and the highest in the surfactant-added products. Investigation of the relationship between the halogenated VOCs and several product ingredients indicated that chlorinated VOC formation is closely related to product composition. Indoor air concentrations from the household use of bleach products (i.e., bathroom, kitchen, and hallway cleaning) were estimated for the two dominating VOCs (chloroform and carbon tetrachloride). Estimated indoor concentrations ranged between 0.5 and 1030 (34 ± 123, average ± SD) μg m-3 and 0.3-1124 (82 ± 194, average ± SD) μg m-3 for chloroform and carbon tetrachloride, respectively, indicating substantial increases compared to background. Results indicated that indoor air concentrations from surfactant-added products were significantly higher (p < 0.01) than other categories. The highest concentrations were from the use of surfactant-added bleach products for bathroom cleaning (92 ± 228 and 224 ± 334 μg m-3, average ± SD for chloroform and carbon tetrachloride, respectively). Associated carcinogenic risks from the use of these products were also estimated. The risk levels may reach to considerably high levels for a significant portion of the population especially for those steadily using the surfactant-added bleach products. Based on the results of the present study, it could be recommended that if possible the use of chlorine bleach containing household products should be avoided. If they are to be used, plain products should be preferred since the chlorinated VOC content increase with the number and amount of additives.

Understanding the Halogenation Effects in Diketopyrrolopyrrole-Based Small Molecule Photovoltaics.

PubMed

Sun, Shi-Xin; Huo, Yong; Li, Miao-Miao; Hu, Xiaowen; Zhang, Hai-Jun; Zhang, You-Wen; Zhang, You-Dan; Chen, Xiao-Long; Shi, Zi-Fa; Gong, Xiong; Chen, Yongsheng; Zhang, Hao-Li

2015-09-16

Two molecules containing a central diketopyrrolopyrrole and two oligothiophene units have been designed and synthesized. Comparisons between the molecules containing terminal F (FDPP) and Cl (CDPP) atoms allowed us to evaluate the effects of halogenation on the photovoltaic properties of the small molecule organic solar cells (OSCs). The OSCs devices employing FDPP:PC71BM films showed power conversion efficiencies up to 4.32%, suggesting that fluorination is an efficient method for constructing small molecules for OSCs.

Control of aliphatic halogenated DBP precursors with multiple drinking water treatment processes: Formation potential and integrated toxicity.

PubMed

Zhang, Yimeng; Chu, Wenhai; Yao, Dechang; Yin, Daqiang

2017-08-01

The comprehensive control efficiency for the formation potentials (FPs) of a range of regulated and unregulated halogenated disinfection by-products (DBPs) (including carbonaceous DBPs (C-DBPs), nitrogenous DBPs (N-DBPs), and iodinated DBPs (I-DBPs)) with the multiple drinking water treatment processes, including pre-ozonation, conventional treatment (coagulation-sedimentation, pre-sand filtration), ozone-biological activated carbon (O 3 -BAC) advanced treatment, and post-sand filtration, was investigated. The potential toxic risks of DBPs by combing their FPs and toxicity values were also evaluated. The results showed that the multiple drinking water treatment processes had superior performance in removing organic/inorganic precursors and reducing the formation of a range of halogenated DBPs. Therein, ozonation significantly removed bromide and iodide, and thus reduced the formation of brominated and iodinated DBPs. The removal of organic carbon and nitrogen precursors by the conventional treatment processes was substantially improved by O 3 -BAC advanced treatment, and thus prevented the formation of chlorinated C-DBPs and N-DBPs. However, BAC filtration leads to the increased formation of brominated C-DBPs and N-DBPs due to the increase of bromide/DOC and bromide/DON. After the whole multiple treatment processes, the rank order for integrated toxic risk values caused by these halogenated DBPs was haloacetonitriles (HANs)≫haloacetamides (HAMs)>haloacetic acids (HAAs)>trihalomethanes (THMs)>halonitromethanes (HNMs)≫I-DBPs (I-HAMs and I-THMs). I-DBPs failed to cause high integrated toxic risk because of their very low FPs. The significant higher integrated toxic risk value caused by HANs than other halogenated DBPs cannot be ignored. Copyright © 2017. Published by Elsevier B.V.

Atomic resolution ADF-STEM imaging of organic molecular crystal of halogenated copper phthalocyanine.

PubMed

Haruta, Mitsutaka; Yoshida, Kaname; Kurata, Hiroki; Isoda, Seiji

2008-05-01

Annular dark-field (ADF) scanning transmission electron microscopy (STEM) measurements are demonstrated for the first time to be applicable for acquiring Z-contrast images of organic molecules at atomic resolution. High-angle ADF imaging by STEM is a new technique that provides incoherent high-resolution Z-contrast images for organic molecules. In the present study, low-angle ADF-STEM is successfully employed to image the molecular crystal structure of hexadecachloro-Cu-phthalocyanine (Cl16-CuPc), an organic molecule. The structures of CuPc derivatives (polyhalogenated CuPc with Br and Cl) are determined quantitatively using the same technique to determine the occupancy of halogens at each chemical site. By comparing the image contrasts of atomic columns, the occupancy of Br is found to be ca. 56% at the inner position, slightly higher than that for random substitution and in good agreement with previous TEM results.

Electrochemical treatment of reverse osmosis concentrate on boron-doped electrodes in undivided and divided cell configurations.

PubMed

Bagastyo, Arseto Y; Batstone, Damien J; Kristiana, Ina; Escher, Beate I; Joll, Cynthia; Radjenovic, Jelena

2014-08-30

An undivided electrolytic cell may offer lower electrochlorination through reduction of chlorine/hypochlorite at the cathode. This study investigated the performance of electrooxidation of reverse osmosis concentrate using boron-doped diamond electrodes in membrane-divided and undivided cells. In both cell configurations, similar extents of chemical oxygen demand and dissolved organic carbon removal were obtained. Continuous formation of chlorinated organic compounds was observed regardless of the membrane presence. However, halogenation of the organic matter did not result in a corresponding increase in toxicity (Vibrio fischeri bioassay performed on extracted samples), with toxicity decreasing slightly until 10AhL(-1), and generally remaining near the initial baseline-toxicity equivalent concentration (TEQ) of the raw concentrate (i.e., ∼2mgL(-1)). The exception was a high range toxicity measure in the undivided cell (i.e., TEQ=11mgL(-1) at 2.4AhL(-1)), which rapidly decreased to 4mgL(-1). The discrepancy between the halogenated organic matter and toxicity patterns may be a consequence of volatile and/or polar halogenated by-products formed in oxidation by OH electrogenerated at the anode. The undivided cell exhibited lower energy compared to the divided cell, 0.25kWhgCOD(-1) and 0.34kWhgCOD(-1), respectively, yet it did not demonstrate any improvement regarding by-products formation. Copyright © 2014 Elsevier B.V. All rights reserved.

Removal of organic contaminants from secondary effluent by anodic oxidation with a boron-doped diamond anode as tertiary treatment.

PubMed

Garcia-Segura, Sergi; Keller, Jürg; Brillas, Enric; Radjenovic, Jelena

2015-01-01

Electrochemical advanced oxidation processes (EAOPs) have been widely investigated as promising technologies to remove trace organic contaminants from water, but have rarely been used for the treatment of real waste streams. Anodic oxidation with a boron-doped diamond (BDD) anode was applied for the treatment of secondary effluent from a municipal sewage treatment plant containing 29 target pharmaceuticals and pesticides. The effectiveness of the treatment was assessed from the contaminants decay, dissolved organic carbon and chemical oxygen demand removal. The effect of applied current and pH was evaluated. Almost complete mineralization of effluent organic matter and trace contaminants can be obtained by this EAOP primarily due to the action of hydroxyl radicals formed at the BDD surface. The oxidation of Cl(-) ions present in the wastewater at the BDD anode gave rise to active chlorine species (Cl2/HClO/ClO(-)), which are competitive oxidizing agents yielding chloramines and organohalogen byproducts, quantified as adsorbable organic halogen. However, further anodic oxidation of HClO/ClO(-) species led to the production of ClO3(-) and ClO4(-) ions. The formation of these species hampers the application as a single-stage tertiary treatment, but posterior cathodic reduction of chlorate and perchlorate species may reduce the risks associated to their presence in the environment. Copyright © 2014 Elsevier B.V. All rights reserved.

Organic Elemental Analysis.

ERIC Educational Resources Information Center

Ma, T. S.; Wang, C. Y.

1984-01-01

Presents a literature review on methods used to analyze organic elements. Topic areas include methods for: (1) analyzing carbon, hydrogen, and nitrogen; (2) analyzing oxygen, sulfur, and halogens; (3) analyzing other elements; (4) simultaneously determining several elements; and (5) determing trace elements. (JN)

Organic Lecture Demonstrations.

ERIC Educational Resources Information Center

Silversmith, Ernest F.

1988-01-01

Provides a listing of 35 demonstrations designed to generate interest in organic chemistry and help put points across. Topics include opening lecture; molecular structure and properties; halogenation; nucleophilic substitution, alkenes and dienes, stereochemistry, spectroscopy, alcohols and phenols, aldehydes and ketones; carboxylic acids, amines,…

Using a refrigerant leak detector to monitor waste gases from halogenated anesthetics.

PubMed

Rasmussen, Henrik; Thorud, Syvert

2007-09-01

Although halogenated gas anesthetics are indispensable in laboratory animal medicine, they are hazardous when present in the working environment. A simple technique of real-time leak detection and environmental spot monitoring can provide valuable adjunct information to current techniques of time-weighted monitoring. We investigated the minimal limit of detection of halothane, isoflurane, sevoflurane, and desflurane of a leak detector for halogenated gas refrigerants which provides a qualitative response only. We connected a container to an infrared gas analyzer to create a 135-l closed-circuit system and injected liquid halothane, isoflurane, sevoflurane, and desflurane to create calculated gas concentrations of 0.7 to 3.4 parts per million (ppm). The infrared absorbance and response of the leak detector were recorded, and a total of 5 measurements were made per concentration. The actual gas concentrations were calculated by comparison with the agent-specific absorbance standard curve. The leak detector clearly and consistently responded to halothane, isoflurane, sevoflurane, and desflurane from minimal concentrations of 2.1 +/- 0.2, 1.4 +/- 0.04, 0.8 +/- 0.04, and 1.2 +/- 0.4 ppm, respectively, as determined by infrared analysis. Although the detector does not provide numerical and time-weighted results, leak testing of equipment and repeated monitoring of the environment (spot monitoring) can provide valuable real-time information. In addition, with appropriate consideration of the methodological limitations, spot monitoring can be used to predict the likelihood of compliance with time-weighted exposure recommendations. A leak detector therefore represents a simple, effective, and inexpensive instrument for monitoring the leakage of halogenated anesthetic gases from equipment and into the working environment.

Volatile halogenated hydrocarbons in foods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyahara, Makoto; Toyoda, Masatake; Saito, Yukio

1995-02-01

Volatile halogenated organic compounds were determined in foods. Statistical treatment of the data for 13 sampled from 20 families living in suburban Tokyo (Saitama prefecture) indicated that the foods were contaminated by water pollution and/or substances introduced by the process of food production. Butter and margarine were contaminated by chlorinated ethylene, ethane, and related compounds released by dry cleaning and other operations. Soybean sprouts and tofu (soybean curd) contained chloroform and related trihalomethanes absorbed during the production process. 27 refs., 6 figs., 5 tabs.

ORGANIZATION II, NOVA SCIENCE UNIT 3.

ERIC Educational Resources Information Center

Broward County Schools, Fort Lauderdale, FL.

THE ORGANIZATION OF THE NATURE OF SCIENCE IS EMPHASIZED THROUGH A FOCUS ON CHEMICAL REACTIONS. SIMILARITIES OF THE REACTIONS OF THE HALOGENS WITH THE ALKALI METALS OF LITHIUM, SODIUM, POTASSIUM, AND HYDROGEN ARE INTRODUCED TO THE STUDENT. STUDENTS ARE INTRODUCED TO THE PERIODIC TABLE OF ELEMENTS WHICH EMPHASIZES THE ORGANIZATION OF CHEMICAL…

Large Plasmids from Soil Bacteria Enriched on Halogenated Alkanoic Acids

PubMed Central

Hardman, David J.; Gowland, Peter C.; Slater, J. Howard

1986-01-01

Four Pseudomonas species and two Alcaligenes species were isolated from soil with a capacity to grow on halogenated alkanoic acids. They were shown to contain one of five large plasmids. The plasmids had molecular weights ranging from 98,800 to 190,000. They were associated with the ability to utilize the halogenated substrates 2-monochloropropionic acid and 2-monochloroacetic acid and with resistance towards one or more of the heavy metals mercury, selenium, and tellurium. The largest plasmid, pUU204, was shown to be unstable in continuous-flow culture when the organism was supplied with succinate as the sole carbon source. The dehalogenase gene associated with pUU204 appeared to be readily transferred to an incP group plasmid, R68-45. PMID:16346975

Defect engineered oxides for enhanced mechanochemical destruction of halogenated organic pollutants.

PubMed

Cagnetta, Giovanni; Huang, Jun; Lu, Mengnan; Wang, Bin; Wang, Yujue; Deng, Shubo; Yu, Gang

2017-10-01

Mechanochemical activation of metal oxides is studied by a novel methodology based on solid state reaction with a stable radical specie. Such approach corroborates that vacancy formation by high energy ball milling, also in nonreducible oxides, is responsible for electron release on particles' surfaces. This finding suggests a new defect engineering strategy to improve effectiveness of metal oxides as co-milling reagent for halogenated organic pollutant destruction. Results prove that high valent metal doping of a commonly employed co-milling reagent such as CaO determines 2.5 times faster pollutant degradation rate. This enhancement is due to electron-rich defects generated by the dopant; electrons are transferred to the organic pollutant thus causing its mineralization. The proposed strategy can be easily applied to other reagents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Organic Elemental Analysis.

ERIC Educational Resources Information Center

Ma, T. S.; Gutterson, Milton

1980-01-01

Reviews general developments in computerization and data processing of organic elemental analyses; carbon, hydrogen, and nitrogen analyzers; procedures for determining oxygen, sulfur, and halogens, as well as other nometallic elements and organometallics. Selected papers on trace analysis of nonmetals and determination of metallic elements are…

VOLATILE ORGANIC CHEMICALS IN 10 PUBLIC-ACCESS BUILDINGS

EPA Science Inventory

The U.S. EPA carried out studies of indoor air quality in 10 buildings. Qualitative analysis identified over 200 aromatics, halogens, esters, alcohols, phenols, ethers, ketones, aldehydes, and epoxides, in addition to several hundred aliphatic hydrocarbons. The total organic load...

Used Solvent Testing and Reclamation. Volume 2. Vapor Degreasing and Precision Cleaning Solvents

DTIC Science & Technology

1988-12-01

of 5 to 500 ppm in halogenated solvents using Karl - Fischer reagent. Arbitrary criteria to identify a spent solvent have evolved in various industries... methods of managing waste solvent. Some DOD installations are reclaiming used solvents rather than discarding them. Reclamation is feasible because the...most E E CT E reliable methods for testing solvent quality. Further testing isnecessary for chlorinated solvents to determine the inhibitor con- FEB 24

Effectiveness of Commercially Available Home Water Purification Systems for Removing Organic Contaminants.

DTIC Science & Technology

1986-09-01

DEVELOPMENT OF DATA REGARDING REMOVAL CAPABILITIES OF HOME WATER TREATMENT UNITS .... 13 C. THE AMWAY WATER TREATMENT SYSTEM .. ......... . 14 D. UPDATE...10 4 Range of Percentage Reduction for Specific Halogenated Organics . . . ..................... 115 Amway Data for...Water-Soluble Organics. . ......... 17 6 Amway Data for Water-Insoluble Organics .......... .. 21 7 Percent Reduction Efficiencies .............. 25

Pollution profiles and health risk assessment of VOCs emitted during e-waste dismantling processes associated with different dismantling methods.

PubMed

An, Taicheng; Huang, Yong; Li, Guiying; He, Zhigui; Chen, Jiangyao; Zhang, Chaosheng

2014-12-01

Pollution profiles of typical volatile organic compounds (VOCs) emitted during dismantling of various printed circuit board assemblies (PCBAs) of e-wastes using different methods were comparatively investigated in the real e-waste dismantling workshops in South China in April 2013. Similar pollution profiles and concentrations of VOCs were observed between dismantling mobile phone and hard disk PCBAs by using electric blowers and between dismantling television and power supplier PCBAs using electric heating furnaces. Aromatic hydrocarbons (accounting for >60% of the sum of VOCs) were the dominant group during using electric blowers, while aromatic (accounting for >44% of the sum of VOCs) and halogenated hydrocarbons (accounting for >48% of the sum of VOCs) were the two dominant groups which contributed equally using electric heating furnaces. However, the distribution profiles of VOCs emitted during dismantling of televisions, hard disks and micro motors using rotary incinerators varied greatly, though aromatic hydrocarbons were still the dominant group. The combustion of e-wastes led to the most severe contamination of VOCs, with total VOCs (3.3×10(4) μg m(-3)) using rotary incinerators about 190, 180, 139, and 40 times higher than those using mechanical cutting, electric soldering iron, electric blower, and electric heating furnace, respectively. Both cancer and non-cancer risks existed for workers due to exposure to on-site emitted VOCs in all workshops especially in those using rotary incinerators according to the USEPA methodology, whereas only cancer risks existed in rotary incinerator workshops according to the American Conference of Industrial Hygienists methodology. Copyright © 2014 Elsevier Ltd. All rights reserved.

PCBs and PCDD/Fs in soil from informal e-waste recycling sites and open dumpsites in India: Levels, congener profiles and health risk assessment.

PubMed

Chakraborty, Paromita; Selvaraj, Sakthivel; Nakamura, Masafumi; Prithiviraj, Balasubramanian; Cincinelli, Alessandra; Bang, John J

2018-04-15

Growth of informal electronic waste (e-waste) recycling sector is an emerging problem for India. The presence of halogenated compounds in e-wastes may result in the formation of persistent organic pollutants like polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during recycling processes. We therefore investigated PCBs and PCDD/Fs in surface soils explicitly from the informal e-waste recycling sites and nearby open dumpsites of major metropolitan cities from four corners of India, viz., New Delhi (North), Kolkata (East), Mumbai (West) and Chennai (South). In the informal e-waste recycling sites, the range of Σ 26 PCBs (0.4-488ng/g) and ƩPCDD/Fs (1.0-10.6ng/g) were higher than Ʃ 26 PCBs (0.3-21ng/g) and ƩPCDD/Fs (0.15-7.3ng/g) from open dumpsites. In the e-waste sites, ƩPCDDs were found with increasing trend from ƩTetraCDD to OctaCDD, whereas ƩPCDFs showed a reverse trend. The dominance of PCDF congeners and maximum toxicity equivalents (TEQ) for both PCDDs (17pg TEQ/g) and PCDFs (82pg TEQ/g) at Mandoli in New Delhi has been related to intensive precious metal recovery process using acid bath. Among dumpsites, highest TEQ for PCDD/Fs was observed at Kodangaiyur dumpsite of Chennai (CN DS -02, 45pg TEQ/g). Positive Matrix Factorization (PMF) model identified distinct congener pattern based on the functional activities, such as e-waste dismantling, shredding, precious metal recovery and open burning in dumpsites. E-waste metal recovery factor was loaded with 86-91% of PCB-77, -105, -114, -118 and 30% of PCB-126, possibly associated with the burning of wires during the copper extraction process. Almost 70% of the Ʃ 26 PCB concentrations was comprised of the dioxin-like PCB congeners with a maximum concentration of 437ng/g at New Moore market in Chennai, followed by Wire Lane (102ng/g), in Mumbai. We speculate that PCB-126 might have resulted from combustion of plastic materials in e-waste stream and dumped waste. Copyright © 2017 Elsevier B.V. All rights reserved.

The halogenated metabolism of brown algae (Phaeophyta), its biological importance and its environmental significance.

PubMed

La Barre, Stéphane; Potin, Philippe; Leblanc, Catherine; Delage, Ludovic

2010-03-31

Brown algae represent a major component of littoral and sublittoral zones in temperate and subtropical ecosystems. An essential adaptive feature of this independent eukaryotic lineage is the ability to couple oxidative reactions resulting from exposure to sunlight and air with the halogenations of various substrates, thereby addressing various biotic and abiotic stresses i.e., defense against predators, tissue repair, holdfast adhesion, and protection against reactive species generated by oxidative processes. Whereas marine organisms mainly make use of bromine to increase the biological activity of secondary metabolites, some orders of brown algae such as Laminariales have also developed a striking capability to accumulate and to use iodine in physiological adaptations to stress. We review selected aspects of the halogenated metabolism of macrophytic brown algae in the light of the most recent results, which point toward novel functions for iodide accumulation in kelps and the importance of bromination in cell wall modifications and adhesion properties of brown algal propagules. The importance of halogen speciation processes ranges from microbiology to biogeochemistry, through enzymology, cellular biology and ecotoxicology.

Organohalide respiration in pristine environments: implications for the natural halogen cycle.

PubMed

Atashgahi, Siavash; Häggblom, Max M; Smidt, Hauke

2018-03-01

Halogenated organic compounds, also termed organohalogens, were initially considered to be of almost exclusively anthropogenic origin. However, over 5000 naturally synthesized organohalogens are known today. This has also fuelled the hypothesis that the natural and ancient origin of organohalogens could have primed development of metabolic machineries for their degradation, especially in microorganisms. Among these, a special group of anaerobic microorganisms was discovered that could conserve energy by reducing organohalogens as terminal electron acceptor in a process termed organohalide respiration. Originally discovered in a quest for biodegradation of anthropogenic organohalogens, these organohalide-respiring bacteria (OHRB) were soon found to reside in pristine environments, such as the deep subseafloor and Arctic tundra soil with limited/no connections to anthropogenic activities. As such, accumulating evidence suggests an important role of OHRB in local natural halogen cycles, presumably taking advantage of natural organohalogens. In this minireview, we integrate current knowledge regarding the natural origin and occurrence of industrially important organohalogens and the evolution and spread of OHRB, and describe potential implications for natural halogen and carbon cycles. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

The Halogenated Metabolism of Brown Algae (Phaeophyta), Its Biological Importance and Its Environmental Significance

PubMed Central

La Barre, Stéphane; Potin, Philippe; Leblanc, Catherine; Delage, Ludovic

2010-01-01

Brown algae represent a major component of littoral and sublittoral zones in temperate and subtropical ecosystems. An essential adaptive feature of this independent eukaryotic lineage is the ability to couple oxidative reactions resulting from exposure to sunlight and air with the halogenations of various substrates, thereby addressing various biotic and abiotic stresses i.e., defense against predators, tissue repair, holdfast adhesion, and protection against reactive species generated by oxidative processes. Whereas marine organisms mainly make use of bromine to increase the biological activity of secondary metabolites, some orders of brown algae such as Laminariales have also developed a striking capability to accumulate and to use iodine in physiological adaptations to stress. We review selected aspects of the halogenated metabolism of macrophytic brown algae in the light of the most recent results, which point toward novel functions for iodide accumulation in kelps and the importance of bromination in cell wall modifications and adhesion properties of brown algal propagules. The importance of halogen speciation processes ranges from microbiology to biogeochemistry, through enzymology, cellular biology and ecotoxicology. PMID:20479964

Direct heteroarylation polymerization: guidelines for defect-free conjugated polymers.

PubMed

Bura, Thomas; Beaupré, Serge; Légaré, Marc-André; Quinn, Jesse; Rochette, Etienne; Blaskovits, J Terence; Fontaine, Frédéric-Georges; Pron, Agnieszka; Li, Yuning; Leclerc, Mario

2017-05-01

Direct (hetero)arylation polymerization (DHAP) has emerged as a valuable and atom-economical alternative to traditional cross-coupling methods for the synthesis of low-cost and efficient conjugated polymers for organic electronics. However, when applied to the synthesis of certain (hetero)arene-based materials, a lack of C-H bond selectivity has been observed. To prevent such undesirable side-reactions, we report the design and synthesis of new, bulky, phosphine-based ligands that significantly enhance selectivity of the DHAP process for both halogenated and non-halogenated electron-rich and electron-deficient thiophene-based comonomers. To better understand the selectivity issues, density functional theory (DFT) calculations have been performed on various halogenated and non-halogenated electron-rich and electron-deficient thiophene-based comonomers. Calculations showed that the presence of bromine atoms decreases the energy of activation ( E a ) of the adjacent C-H bonds, allowing undesirable β-defects for some brominated aromatic units. Both calculations and the new ligands should lead to the rational design of monomers and methods for the preparation of defect-free conjugated polymers from DHAP.

A reconnaissance study of halogenated organic compounds in catfish from the lower Mississippi river and its major tributaries

USGS Publications Warehouse

Leiker, T.J.; Rostad, C.E.; Barnes, C.R.; Pereira, W.E.

1991-01-01

Blue catfish, (Ictarurus furcatus), black bullhead catfish, (Ictalurus melas), channel catfish (Ictalurus punctatus), and flathead catfish (Pylodictus olivaris), were collected along a 1200 mile river reach of the Mississippi River and its major tributaries. Tissue samples were extracted and analyzed by fused silica capillary gas chromatography/mass spectrometry (GC/MS) to determine the concentrations of hydrophobic organic halogenated contaminants that have bioconcentrated within the tissues. The compounds identified in the tissue include chlordane, polychlorinated biphenyls (PCBs), DDT and its metabolites along with several other chlorinated pesticides. The data indicates that the southern reach of the river system appears to be more contaminated than the middle and upper reaches of the study area.

In situ thermally enhanced biodegradation of petroleum fuel hydrocarbons and halogenated organic solvents

DOEpatents

Taylor, Robert T.; Jackson, Kenneth J.; Duba, Alfred G.; Chen, Ching-I

1998-01-01

An in situ thermally enhanced microbial remediation strategy and a method for the biodegradation of toxic petroleum fuel hydrocarbon and halogenated organic solvent contaminants. The method utilizes nonpathogenic, thermophilic bacteria for the thermal biodegradation of toxic and carcinogenic contaminants, such as benzene, toluene, ethylbenzene and xylenes, from fuel leaks and the chlorinated ethenes, such as trichloroethylene, chlorinated ethanes, such as 1,1,1-trichloroethane, and chlorinated methanes, such as chloroform, from past solvent cleaning practices. The method relies on and takes advantage of the pre-existing heated conditions and the array of delivery/recovery wells that are created and in place following primary subsurface contaminant volatilization efforts via thermal approaches, such as dynamic underground steam-electrical heating.

In situ thermally enhanced biodegradation of petroleum fuel hydrocarbons and halogenated organic solvents

DOEpatents

Taylor, R.T.; Jackson, K.J.; Duba, A.G.; Chen, C.I.

1998-05-19

An in situ thermally enhanced microbial remediation strategy and a method for the biodegradation of toxic petroleum fuel hydrocarbon and halogenated organic solvent contaminants are described. The method utilizes nonpathogenic, thermophilic bacteria for the thermal biodegradation of toxic and carcinogenic contaminants, such as benzene, toluene, ethylbenzene and xylenes, from fuel leaks and the chlorinated ethenes, such as trichloroethylene, chlorinated ethanes, such as 1,1,1-trichloroethane, and chlorinated methanes, such as chloroform, from past solvent cleaning practices. The method relies on and takes advantage of the pre-existing heated conditions and the array of delivery/recovery wells that are created and in place following primary subsurface contaminant volatilization efforts via thermal approaches, such as dynamic underground steam-electrical heating. 21 figs.

Non-targeted analysis of electronics waste by comprehensive two-dimensional gas chromatography combined with high-resolution mass spectrometry: Using accurate mass information and mass defect analysis to explore the data.

PubMed

Ubukata, Masaaki; Jobst, Karl J; Reiner, Eric J; Reichenbach, Stephen E; Tao, Qingping; Hang, Jiliang; Wu, Zhanpin; Dane, A John; Cody, Robert B

2015-05-22

Comprehensive two-dimensional gas chromatography (GC×GC) and high-resolution mass spectrometry (HRMS) offer the best possible separation of their respective techniques. Recent commercialization of combined GC×GC-HRMS systems offers new possibilities for the analysis of complex mixtures. However, such experiments yield enormous data sets that require new informatics tools to facilitate the interpretation of the rich information content. This study reports on the analysis of dust obtained from an electronics recycling facility by using GC×GC in combination with a new high-resolution time-of-flight (TOF) mass spectrometer. New software tools for (non-traditional) Kendrick mass defect analysis were developed in this research and greatly aided in the identification of compounds containing chlorine and bromine, elements that feature in most persistent organic pollutants (POPs). In essence, the mass defect plot serves as a visual aid from which halogenated compounds are recognizable on the basis of their mass defect and isotope patterns. Mass chromatograms were generated based on specific ions identified in the plots as well as region of the plot predominantly occupied by halogenated contaminants. Tentative identification was aided by database searches, complementary electron-capture negative ionization experiments and elemental composition determinations from the exact mass data. These included known and emerging flame retardants, such as polybrominated diphenyl ethers (PBDEs), hexabromobenzene, tetrabromo bisphenol A and tris (1-chloro-2-propyl) phosphate (TCPP), as well as other legacy contaminants such as polychlorinated biphenyls (PCBs) and polychlorinated terphenyls (PCTs). Copyright © 2015 Elsevier B.V. All rights reserved.

Quantitative prediction of solvation free energy in octanol of organic compounds.

PubMed

Delgado, Eduardo J; Jaña, Gonzalo A

2009-03-01

The free energy of solvation, DeltaGS0, in octanol of organic compounds is quantitatively predicted from the molecular structure. The model, involving only three molecular descriptors, is obtained by multiple linear regression analysis from a data set of 147 compounds containing diverse organic functions, namely, halogenated and non-halogenated alkanes, alkenes, alkynes, aromatics, alcohols, aldehydes, ketones, amines, ethers and esters; covering a DeltaGS0 range from about -50 to 0 kJ.mol(-1). The model predicts the free energy of solvation with a squared correlation coefficient of 0.93 and a standard deviation, 2.4 kJ.mol(-1), just marginally larger than the generally accepted value of experimental uncertainty. The involved molecular descriptors have definite physical meaning corresponding to the different intermolecular interactions occurring in the bulk liquid phase. The model is validated with an external set of 36 compounds not included in the training set.

Quantitative Prediction of Solvation Free Energy in Octanol of Organic Compounds

PubMed Central

Delgado, Eduardo J.; Jaña, Gonzalo A.

2009-01-01

The free energy of solvation, ΔGS0, in octanol of organic compunds is quantitatively predicted from the molecular structure. The model, involving only three molecular descriptors, is obtained by multiple linear regression analysis from a data set of 147 compounds containing diverse organic functions, namely, halogenated and non-halogenated alkanes, alkenes, alkynes, aromatics, alcohols, aldehydes, ketones, amines, ethers and esters; covering a ΔGS0 range from about −50 to 0 kJ·mol−1. The model predicts the free energy of solvation with a squared correlation coefficient of 0.93 and a standard deviation, 2.4 kJ·mol−1, just marginally larger than the generally accepted value of experimental uncertainty. The involved molecular descriptors have definite physical meaning corresponding to the different intermolecular interactions occurring in the bulk liquid phase. The model is validated with an external set of 36 compounds not included in the training set. PMID:19399236

Hepatic ethoxyresorufin-O-deethylase induction in the common kingfisher from an electronic waste recycling site.

PubMed

Wu, Jiang-Ping; Mo, Ling; Zhi, Hui; Peng, Ying; Tao, Lin; Ren, Zi-He; Luo, Xiao-Jun; Mai, Bi-Xian

2016-06-01

The health effects of exposure to electronic waste (e-waste)-derived pollutants are an important issue. The authors explored the association between the hepatic levels of e-waste-derived halogenated contaminants (including polychlorinated biphenyls [PCBs], polybrominated diphenyl ethers [PBDEs], and polybrominated biphenyls [PBBs]) and hepatic ethoxyresorufin-O-deethylase (EROD) activity of the common kingfisher (Alcedo atthis) from an e-waste site and 2 reference sites in South China. The summed concentrations of PCBs, PBDEs, and PBBs ranged from 620 ng/g to 15 000 ng/g, 25 ng/g to 900 ng/g, and 14 ng/g to 49 ng/g wet weight, respectively, in the kingfishers from the e-waste site, and these values were significantly greater (2-3 orders of magnitude) than those obtained at the 2 reference sites. Correspondingly, significant hepatic EROD induction was observed in the kingfishers from the e-waste site compared with the reference sites. The EROD activity was significantly correlated to the levels of most of the PCB and PBDE congeners examined as well as PBB 153, suggesting that EROD induction may be evoked by these e-waste-derived pollutants. Environ Toxicol Chem 2016;35:1594-1599. © 2015 SETAC. © 2015 SETAC.

CHLORINATED SOLVENT PLUME CONTROL

EPA Science Inventory

This lecture will cover recent success in controlling and assessing the treatment of shallow ground water plumes of chlorinated solvents, other halogenated organic compounds, and methyl tert-butyl ether (MTBE).

The toxicity of brominated and mixed-halogenated dibenzo-p-dioxins and dibenzofurans: An overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, L.W.D.; Greim, H.

1997-02-21

Brominated dibenzo-p-dioxins and dibenzofurans can be formed under laboratory conditions by pyrolysis of flame retardants based on polybrominated biphenyls and biphenyl ethers. Their occurrence in the environment, however, is due to combustion processes such as municipal waste incineration and internal combustion engines. As these processes generally take place in the presence of an excess of chlorine, predominantly mixed brominated and chlorinated compounds have been identified so far in environmental samples. Brominated dibenzo-p-dioxins or dibenzofurans bind to the cytosolic Ah receptor about as avidly as their chlorinated congeners and induce hepatic microsomal enzymes with comparable potency. The same holds true formore » mixed brominated-chlorinated compounds. Gross pathologic symptoms-hypothyroidism, thymic atrophy, wasting of body mass, lethality-also occur at doses that, on a molar concentration basis, are virtually identical to those seen with the chlorinated compounds. Their potency to induce malformations in mice following prenatal exposure is equivalent to that of chlorinated dibenzo-p-dioxins and dibenzofurans. Possible activities as (co)carcinogens and endocrine disrupters have not been evaluated, but are likely to exist. Considering the overall similarity in action of chlorinated and brominated dibenzo-p-dioxins and dibenzofurans, environmental and health assessment should be based on molar body burdens without discrimination for the nature of the halogen. 107 refs., 1 fig., 7 tabs.« less

Management of exposure to waste anesthetic gases.

PubMed

Smith, Francis Duval

2010-04-01

Anesthetic agents were developed in the 1700s, and nitrous oxide was first used in 1884. Research on the effects of waste anesthetic gas exposure started appearing in the literature in 1967. Short-term exposure causes lethargy and fatigue, and long-term exposure may be linked to spontaneous abortion, congenital abnormalities, infertility, premature births, cancer, and renal and hepatic disease. Today, perioperative staff members are exposed to trace amounts of waste anesthetic gas, and although this exposure cannot be eliminated, it can be controlled. Health care facilities are required to develop, implement, measure, and control practices to reduce anesthetic gas exposure to the lowest practical level. Exposure levels must be measured every six months and maintained at less than 25 parts per million for nitrous oxide and 2 parts per million for halogenated agents to be compliant with Occupational Safety and Health Administration standards. Copyright 2010 AORN, Inc. Published by Elsevier Inc. All rights reserved.

A Haloalkane Dehalogenase from a Marine Microbial Consortium Possessing Exceptionally Broad Substrate Specificity.

PubMed

Buryska, Tomas; Babkova, Petra; Vavra, Ondrej; Damborsky, Jiri; Prokop, Zbynek

2018-01-15

The haloalkane dehalogenase enzyme DmmA was identified by marine metagenomic screening. Determination of its crystal structure revealed an unusually large active site compared to those of previously characterized haloalkane dehalogenases. Here we present a biochemical characterization of this interesting enzyme with emphasis on its structure-function relationships. DmmA exhibited an exceptionally broad substrate specificity and degraded several halogenated environmental pollutants that are resistant to other members of this enzyme family. In addition to having this unique substrate specificity, the enzyme was highly tolerant to organic cosolvents such as dimethyl sulfoxide, methanol, and acetone. Its broad substrate specificity, high overexpression yield (200 mg of protein per liter of cultivation medium; 50% of total protein), good tolerance to organic cosolvents, and a broad pH range make DmmA an attractive biocatalyst for various biotechnological applications. IMPORTANCE We present a thorough biochemical characterization of the haloalkane dehalogenase DmmA from a marine metagenome. This enzyme with an unusually large active site shows remarkably broad substrate specificity, high overexpression, significant tolerance to organic cosolvents, and activity under a broad range of pH conditions. DmmA is an attractive catalyst for sustainable biotechnology applications, e.g., biocatalysis, biosensing, and biodegradation of halogenated pollutants. We also report its ability to convert multiple halogenated compounds to corresponding polyalcohols. Copyright © 2018 American Society for Microbiology.

REDUCTIVE DEHALOGENATION OF ORGANIC CONTAMINANTS IN SOILS AND GROUND WATER

EPA Science Inventory

Introduction and large scale production of synthetic halogenated organic chemicals over the last 50 years has resulted in a group of contaminants which tend to persist in the environment and resist both biotic and abiotic degradation. The low solubility of these types of contamin...

REDUCTIVE DEHALOGENATION OF ORGANIC CONTAMINANTS IN SOILS AND GROUND WATER

EPA Science Inventory

Introduction and large-scale production of synthetic halogenated organic chemicals over the last fifty years has resulted in a group of contaminants that tend to persist in the environment and resist both biotic and abiotic degradation. The low solubility of these types of contam...

Chiral Alkyl Halides: Underexplored Motifs in Medicine

PubMed Central

Gál, Bálint; Bucher, Cyril; Burns, Noah Z.

2016-01-01

While alkyl halides are valuable intermediates in synthetic organic chemistry, their use as bioactive motifs in drug discovery and medicinal chemistry is rare in comparison. This is likely attributable to the common misconception that these compounds are merely non-specific alkylators in biological systems. A number of chlorinated compounds in the pharmaceutical and food industries, as well as a growing number of halogenated marine natural products showing unique bioactivity, illustrate the role that chiral alkyl halides can play in drug discovery. Through a series of case studies, we demonstrate in this review that these motifs can indeed be stable under physiological conditions, and that halogenation can enhance bioactivity through both steric and electronic effects. Our hope is that, by placing such compounds in the minds of the chemical community, they may gain more traction in drug discovery and inspire more synthetic chemists to develop methods for selective halogenation. PMID:27827902

Iodine(III) Derivatives as Halogen Bonding Organocatalysts.

PubMed

Heinen, Flemming; Engelage, Elric; Dreger, Alexander; Weiss, Robert; Huber, Stefan M

2018-03-26

Hypervalent iodine(III) derivatives are known as versatile reagents in organic synthesis, but there is only one previous report on their use as Lewis acidic organocatalysts. Herein, we present first strong indications for the crucial role of halogen bonding in this kind of catalyses. To this end, the solvolysis of benzhydryl chloride and the Diels-Alder reaction of cyclopentadiene with methyl vinyl ketone served as benchmark reactions for halide abstraction and the activation of neutral compounds. Iodolium compounds (cyclic diaryl iodonium species) were used as activators or catalysts, and we were able to markedly reduce or completely switch off their activity by sterically blocking one or two of their electrophilic axes. Compared with previously established bidentate cationic halogen bond donors, the monodentate organoiodine derivatives used herein are at least similarly active (in the Diels-Alder reaction) or even decidedly more active (in benzhydryl chloride solvolysis). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biodegradation of six haloacetic acids in drinking water.

PubMed

Bayless, Walt; Andrews, Robert C

2008-03-01

Haloacetic acids (HAAs) are produced by the reaction of chlorine with natural organic matter and are regulated disinfection by-products of health concern. Biofilms in drinking water distribution systems and in filter beds have been associated with the removal of some HAAs, however the removal of all six routinely monitored species (HAA(6)) has not been previously reported. In this study, bench-scale glass bead columns were used to investigate the ability of a drinking water biofilm to degrade HAA(6). Monochloroacetic acid (MCAA) and monobromoacetic acid (MBAA) were the most readily degraded of the halogenated acetic acids. Trichloroacetic acid (TCAA) was not removed biologically when examined at a 90% confidence level. In general, di-halogenated species were removed to a lesser extent than the mono-halogenated compounds. The order of biodegradability by the biofilm was found to be monobromo > monochloro > bromochloro > dichloro > dibromo > trichloroacetic acid.

Intrinsic Chemiluminescence Generation during Advanced Oxidation of Persistent Halogenated Aromatic Carcinogens.

PubMed

Mao, Li; Liu, Yu-Xiang; Huang, Chun-Hua; Gao, Hui-Ying; Kalyanaraman, Balaraman; Zhu, Ben-Zhan

2015-07-07

The ubiquitous distribution coupled with their carcinogenicity has raised public concerns on the potential risks to both human health and the ecosystem posed by the halogenated aromatic compounds (XAr). Recently, advanced oxidation processes (AOPs) have been increasingly favored as an "environmentally-green" technology for the remediation of such recalcitrant and highly toxic XAr. Here, we show that AOPs-mediated degradation of the priority pollutant pentachlorophenol and all other XAr produces an intrinsic chemiluminescence that directly depends on the generation of the extremely reactive hydroxyl radicals. We propose that the hydroxyl radical-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual chemiluminescence production. A rapid, sensitive, simple, and effective chemiluminescence method was developed to quantify trace amounts of XAr and monitor their real-time degradation kinetics. These findings may have broad biological and environmental implications for future research on this important class of halogenated persistent organic pollutants.

40 CFR 65.154 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Halogen scrubbers and other halogen... Routing to a Fuel Gas System or a Process § 65.154 Halogen scrubbers and other halogen reduction devices. (a) Halogen scrubber and other halogen reduction device equipment and operating requirements. (1) An...

Influence of the chemical structure on odor qualities and odor thresholds of halogenated guaiacol-derived odorants

NASA Astrophysics Data System (ADS)

Juhlke, Florian; Lorber, Katja; Wagenstaller, Maria; Buettner, Andrea

2017-12-01

Chlorinated guaiacol derivatives are found in waste water of pulp mills using chlorine in the bleaching process of wood pulp. They can also be detected in fish tissue, possibly causing off-odors. To date, there is no systematic investigation on the odor properties of halogenated guaiacol derivatives. To close this gap, odor thresholds in air and odor qualities of 14 compounds were determined by gas chromatography-olfactometry. Overall, the investigated compounds elicited smells that are characteristic for guaiacol, namely smoky, sweet, vanilla-like, but also medicinal and plaster-like. Their odor thresholds in air were, however, very low, ranging from 0.00072 to 23 ng/Lair. The lowest thresholds were found for 5-chloro- and 5-bromoguaiacol, followed by 4,5-dichloro- and 6-chloroguaiacol. Moreover, some inter-individual differences in odor threshold values could be observed, with the highest variations having been recorded for the individual values of 5-iodo- and 4-bromoguaiacol.

Molecular Signature of Organic Carbon Along a Salinity Gradient in Suwannee River Plume

NASA Astrophysics Data System (ADS)

Liu, Y.; Bianchi, T. S.; Ward, N. D.; Arellano, A. R.; Paša-Tolić, L.; Tolic, N.; Kuo, L. J.

2016-12-01

Humic and fulvic acid isolates from Suwannee River dissolved organic matter (DOM) have served as reference standards for the International Humic Substances Society (IHSS) for many decades. The large database on Suwannee DOM provides an excellent framework to further expand the application of Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS) in characterizing the chemical composition of aquatic DOM. In this study, we examined the DOM signature of the lower Suwannee River and plume region at 5 stations along a salinity gradient (0 to 28) using FT-ICR-MS. The chemical characteristics of DOM show distinct differences across this steep salinity gradient. In general, samples collected from the coastal station have lower carbon number and are less aromatic. Molecular level analysis reveals that the magnitude weighted proportion of lipids increased as salinity increased. Interestingly, a similar trend was observed for lignin-like compounds. Target quantification of lignin-phenols showed that while the concentrations of these compounds were lower at the coastal station, the DOC-normalized concentrations were not significantly different between the river and coastal stations. In addition to traditional DOM moieties, we identified for the first time, halogenated organic compounds (HOC). We observed more chlorinated compounds in DOM and increased Cl/C as salinity increased. A relatively high proportion of halogenated lipids (compared to non-halogenated) were observed in the total pool of HOC across all stations. Although not significant in relative proportion, halogenated lignin-like compounds were the most abundant HOC moieties in our samples. CO2 concentrations decreased and became more 13C-enriched along the salinity gradient, ranging from 3,990 ppm (13CO2 = -17.3‰) at salinity 0 to 520 ppm (13CO2 = -7.5‰) at salinity 28, indicating high levels of DOM degradation in the river and a shift to primary production in the marine receiving waters, which is consistent with trends of lipid and lignin-like compounds observed with FT-ICR-MS.

Reduction of halogenated ethanes by green rust.

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Loughlin, E. J.; Burris, D. R.; Environmental Research

Green rusts, mixed Fe{sup II}/Fe{sup III} hydroxide minerals present in many suboxic environments, have been shown to reduce a number of organic and inorganic contaminants. The reduction of halogenated ethanes was examined in aqueous suspensions of green rust, both alone and with the addition of Ag{sup I} (AgGR) and Cu{sup II} (CuGR). Hexachloroethane (HCA), pentachloroethane (PCA), 1,1,1,2-tetrachloroethane (1,1,1,2-TeCA), 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA), 1,1,1-trichloroethane (1,1,1-TCA), 1,1,2-trichloroethane (1,1,2-TCA), 1,1-dichloroethane (1,1-DCA), and 1,2-dibromoethane were reduced in the presence of green rust alone, AgGR, or CuGR; only 1,2-dichloroethane and chloroethane were nonreactive. The reduction was generally more rapid for more highly substituted ethanes than for ethanesmore » having fewer halogen groups (HCA > PCA > 1,1,1,2-TeCA > 1,1,1-TCA > 1,1,2,2-TeCA > 1,1,2-TCA > 1,1-DCA), and isomers with the more asymmetric distributions of halogen groups were more rapidly reduced than the isomer with greater symmetry (e.g., 1,1,1-TCA > 1,1,2-TCA). The addition of Ag{sup I} or Cu{sup II} to green rust suspensions resulted in a substantial increase in the rate of halogenated ethane reduction as well as significant differences in the product distributions with respect to green rust alone.« less

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2012 CFR

2012-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2014 CFR

2014-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

Inkjet-Printed Small-Molecule Organic Light-Emitting Diodes: Halogen-Free Inks, Printing Optimization, and Large-Area Patterning.

PubMed

Zhou, Lu; Yang, Lei; Yu, Mengjie; Jiang, Yi; Liu, Cheng-Fang; Lai, Wen-Yong; Huang, Wei

2017-11-22

Manufacturing small-molecule organic light-emitting diodes (OLEDs) via inkjet printing is rather attractive for realizing high-efficiency and long-life-span devices, yet it is challenging. In this paper, we present our efforts on systematical investigation and optimization of the ink properties and the printing process to enable facile inkjet printing of conjugated light-emitting small molecules. Various factors on influencing the inkjet-printed film quality during the droplet generation, the ink spreading on the substrates, and its solidification processes have been systematically investigated and optimized. Consequently, halogen-free inks have been developed and large-area patterning inkjet printing on flexible substrates with efficient blue emission has been successfully demonstrated. Moreover, OLEDs manufactured by inkjet printing the light-emitting small molecules manifested superior performance as compared with their corresponding spin-cast counterparts.

Evaluation of organic contamination in urban groundwater surrounding a municipal landfill, Zhoukou, China.

PubMed

Han, D M; Tong, X X; Jin, M G; Hepburn, Emily; Tong, C S; Song, X F

2013-04-01

This paper investigates the organic pollution status of shallow aquifer sediments and groundwater around Zhoukou landfill. Chlorinated aliphatic hydrocarbons, monocylic aromatic hydrocarbons, halogenated aromatic hydrocarbons, organochlorine pesticides and other pesticides, and polycyclic aromatic hydrocarbons (PAHs) have been detected in some water samples. Among the detected eleven PAHs, phenanthrene, fluorine, and fluoranthene are the three dominant in most of the groundwater samples. Analysis of groundwater samples around the landfill revealed concentrations of PAHs ranging from not detected to 2.19 μg/L. The results show that sediments below the waste dump were low in pollution, and the shallow aquifer, at a depth of 18-30 m, was heavily contaminated, particularly during the wet season. An oval-shaped pollution halo has formed, spanning 3 km from west to east and 2 km from south to north, and mainly occurs in groundwater depths of 2-4 m. For PAH source identification, both diagnostic ratios of selected PAHs and principal component analysis were studied, suggesting mixed sources of pyro- and petrogenic derived PAHs in the Zhoukou landfill. Groundwater table fluctuations play an important role in the distribution of organic pollutants within the shallow aquifer. A conceptual model of leachate migration in the Quaternary aquifers surrounding the Zhoukou landfill has been developed to describe the contamination processes based on the major contaminant (PAHs). The groundwater zone contaminated by leachate has been identified surrounding the landfill.

Characterisation and materials flow management for waste electrical and electronic equipment plastics from German dismantling centres.

PubMed

Arends, Dagmar; Schlummer, Martin; Mäurer, Andreas; Markowski, Jens; Wagenknecht, Udo

2015-09-01

Waste electrical and electronic equipment is a complex waste stream and treatment options that work for one waste category or product may not be appropriate for others. A comprehensive case study has been performed for plastic-rich fractions that are treated in German dismantling centres. Plastics from TVs, monitors and printers and small household appliances have been characterised extensively. Based on the characterisation results, state-of-the-art treatment technologies have been combined to design an optimised recycling and upgrade process for each input fraction. High-impact polystyrene from TV casings that complies with the European directive on the restriction of hazardous substances (RoHS) was produced by applying continuous density separation with yields of about 60%. Valuable acrylonitrile butadiene styrene/polycarbonate can be extracted from monitor and printer casings by near-infrared-based sorting. Polyolefins and/or a halogen-free fraction of mixed styrenics can be sorted out by density separation from monitors and printers and small household appliances. Emerging separation technologies are discussed to improve recycling results. © The Author(s) 2015.

The evaluation of an analytical protocol for the determination of substances in waste for hazard classification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hennebert, Pierre, E-mail: pierre.hennebert@ineris.fr; Papin, Arnaud; Padox, Jean-Marie

Highlights: • Knowledge of wastes in substances will be necessary to assess HP1–HP15 hazard properties. • A new analytical protocol is proposed for this and tested by two service laboratories on 32 samples. • Sixty-three percentage of the samples have a satisfactory analytical balance between 90% and 110%. • Eighty-four percentage of the samples were classified identically (Seveso Directive) for their hazardousness by the two laboratories. • The method, in progress, is being normalized in France and is be proposed to CEN. - Abstract: The classification of waste as hazardous could soon be assessed in Europe using largely the hazardmore » properties of its constituents, according to the the Classification, Labelling and Packaging (CLP) regulation. Comprehensive knowledge of the component constituents of a given waste will therefore be necessary. An analytical protocol for determining waste composition is proposed, which includes using inductively coupled plasma (ICP) screening methods to identify major elements and gas chromatography/mass spectrometry (GC–MS) screening techniques to measure organic compounds. The method includes a gross or indicator measure of ‘pools’ of higher molecular weight organic substances that are taken to be less bioactive and less hazardous, and of unresolved ‘mass’ during the chromatography of volatile and semi-volatile compounds. The concentration of some elements and specific compounds that are linked to specific hazard properties and are subject to specific regulation (examples include: heavy metals, chromium(VI), cyanides, organo-halogens, and PCBs) are determined by classical quantitative analysis. To check the consistency of the analysis, the sum of the concentrations (including unresolved ‘pools’) should give a mass balance between 90% and 110%. Thirty-two laboratory samples comprising different industrial wastes (liquids and solids) were tested by two routine service laboratories, to give circa 7000 parameter results. Despite discrepancies in some parameters, a satisfactory sum of estimated or measured concentrations (analytical balance) of 90% was reached for 20 samples (63% of the overall total) during this first test exercise, with identified reasons for most of the unsatisfactory results. Regular use of this protocol (which is now included in the French legislation) has enabled service laboratories to reach a 90% mass balance for nearly all the solid samples tested, and most of liquid samples (difficulties were caused in some samples from polymers in solution and vegetable oil). The protocol is submitted to French and European normalization bodies (AFNOR and CEN) and further improvements are awaited.« less

Use of integrated indoor concentrations of tracer gases and volatile organic compounds to distinguish soil sources from above-ground sources

EPA Science Inventory

Vapor intrusion refers to the situation in which harmful chemicals [such as halogenated or chlorinated volatile organic compounds (VOC) or petroleum products] in the groundwater or soil volatilize in the vadose zone and migrate into the indoor environment. These chemicals typical...

40 CFR Table 4 to Subpart Ffff of... - Emission Limits for Storage Tanks

Code of Federal Regulations, 2010 CFR

2010-07-01

... HAP emissions by ≥95 percent by weight or to ≤20 ppmv of TOC or organic HAP and ≤20 ppmv of hydrogen... ≥95 percent by weight or to ≤20 ppmv of TOC or organic HAP and ≤20 ppmv of hydrogen halide and halogen...

Inorganic bromine in organic molecular crystals: Database survey and four case studies

NASA Astrophysics Data System (ADS)

Nemec, Vinko; Lisac, Katarina; Stilinović, Vladimir; Cinčić, Dominik

2017-01-01

We present a Cambridge Structural Database and experimental study of multicomponent molecular crystals containing bromine. The CSD study covers supramolecular behaviour of bromide and tribromide anions as well as halogen bonded dibromine molecules in crystal structures of organic salts and cocrystals, and a study of the geometries and complexities in polybromide anion systems. In addition, we present four case studies of organic structures with bromide, tribromide and polybromide anions as well as the neutral dibromine molecule. These include the first observed crystal with diprotonated phenazine, a double salt of phenazinium bromide and tribromide, a cocrystal of 4-methoxypyridine with the neutral dibromine molecule as a halogen bond donor, as well as bis(4-methoxypyridine)bromonium polybromide. Structural features of the four case studies are in the most part consistent with the statistically prevalent behaviour indicated by the CSD study for given bromine species, although they do exhibit some unorthodox structural features and in that indicate possible supramolecular causes for aberrations from the statistically most abundant (and presumably most favourable) geometries.

Mixing Halogens To Assemble an All-Inorganic Layered Perovskite with Warm White-Light Emission.

PubMed

Li, Xianfeng; Wang, Sasa; Zhao, Sangen; Li, Lina; Li, Yanqiang; Zhao, Bingqing; Shen, Yaoguo; Wu, Zhenyue; Shan, Pai; Luo, Junhua

2018-05-01

Most of single-component white-light-emitting materials focus on organic-inorganic hybrid perovskites, metal-organic frameworks, as well as all-inorganic semiconductors. In this work, we successfully assembled an all-inorganic layered perovskite by mixing two halogens of distinct ionic radii, namely, Rb 2 CdCl 2 I 2 , which emits "warm" white light with a high color rendering index of 88. To date, Rb 2 CdCl 2 I 2 is the first single-component white-light-emitting material with an all-inorganic layered perovskite structure. Furthermore, Rb 2 CdCl 2 I 2 is thermally highly stable up to 575 K. A series of luminescence measurements show that the white-light emission arises from the lattice deformation, which are closely related to the [CdCl 4 I 2 ] 2- octahedra with high distortion from the distinct ionic radii of Cl and I. The first-principles calculations reveal that both the Cl and I components make significant contributions to the electronic band structures of Rb 2 CdCl 2 I 2 . These findings indicate that mixing halogens is an effective route to design and synthesize new single-component white-light-emitting materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chlorinated organic compounds in urban river sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soma, Y.; Shiraishi, H.; Inaba, K.

1995-12-31

Among anthropogenic chemicals, many chlorinated organic compounds have been used as insecticides and detected frequently as contaminants in urban river sediments so far. However, the number and total amount of chemicals produced commercially and used are increasing year by year, though each amount of chemicals is not so high. New types of contaminants in the environment may be detected by the use of newly developed chemicals. Chlorinated organic compounds in the urban river sediments around Tokyo and Kyoto, large cities in Japan, were surveyed and recent trends of contaminants were studied. Contaminants of the river sediments in industrial areas hadmore » a variety, but PCB (polychlorinated biphenyls) was detected in common in industrial areas. Concentration of PCB related well to the number of factories on both sides of rivers, although the use of PCB was stopped 20 years ago. In domestic areas, Triclosan (5-chloro-2-(2,4-dichlorophenoxy)-phenol) and Triclocarban (3,4,4{prime}-trichlorocarbanilide)(both are contained in soap or shampoo for fungicides), p-dichlorobenzene (insecticides for wears) and TCEP(tris-chloroethyl phosphate) were detected. EOX(extracted organic halogen) in the sediments was 5 to 10 times of chlorinated organic compounds detected by GC/MS. Major part of organic halogen was suggested to be included in chlorinated organics formed by bleaching or sterilization.« less

Multi-Phase Extraction: State-of-the-Practice

EPA Pesticide Factsheets

This report describes the state-of-the-practice for multi-phase extraction (MPE) of contaminated soil and groundwater, focusing primarily on the application and use of MPE at sites with halogenated volatile organic compounds (VOCs).

TCE Removal From Contaminated Soil and Ground Water

EPA Pesticide Factsheets

Trichloroethylene (TCE) is a halogenated aliphatic organic compound which, due to its unique properties and solvent effects, has been widely used as an ingredient in industrial cleaning solutions and as a “universal” degreasing agent.

Assessment of selected contaminants in streambed- and suspended-sediment samples collected in Bexar County, Texas, 2007-09

USGS Publications Warehouse

Wilson, Jennifer T.

2011-01-01

Elevated concentrations of sediment-associated contaminants are typically associated with urban areas such as San Antonio, Texas, in Bexar County, the seventh most populous city in the United States. This report describes an assessment of selected sediment-associated contaminants in samples collected in Bexar County from sites on the following streams: Medio Creek, Medina River, Elm Creek, Martinez Creek, Chupaderas Creek, Leon Creek, Salado Creek, and San Antonio River. During 2007-09, the U.S. Geological Survey periodically collected surficial streambed-sediment samples during base flow and suspended-sediment (large-volume suspended-sediment) samples from selected streams during stormwater runoff. All sediment samples were analyzed for major and trace elements and for organic compounds including halogenated organic compounds and polycyclic aromatic hydrocarbons (PAHs). Selected contaminants in streambed and suspended sediments in watersheds of the eight major streams in Bexar County were assessed by using a variety of methods—observations of occurrence and distribution, comparison to sediment-quality guidelines and data from previous studies, statistical analyses, and source indicators. Trace elements concentrations were low compared to the consensus-based sediment-quality guidelines threshold effect concentration (TEC) and probable effect concentration (PEC). Trace element concentrations were greater than the TEC in 28 percent of the samples and greater than the PEC in 1.5 percent of the samples. Chromium concentrations exceeded sediment-quality guidelines more frequently than concentrations of any other constituents analyzed in this study (greater than the TEC in 69 percent of samples and greater than the PEC in 8 percent of samples). Mean trace element concentrations generally are lower in Bexar County samples compared to concentrations in samples collected during previous studies in the Austin and Fort Worth, Texas, areas, but considering the relatively large ranges and standard deviations associated with the concentrations measured in all three areas, the trace element concentrations are similar. On the basis of Mann-Whitney U test results, the presence of a military installation in a watershed was associated with statistically significant higher chromium, mercury, and zinc concentrations in streambed sediments compared to concentrations of the same elements in a watershed without a military installation. Halogenated organic compounds analyzed in sediment samples included pesticides (chlordane, dieldrin, DDT, DDD, and DDE), polychlorinated biphenyls (PCBs), and brominated flame retardants. Three or more halogenated organic compounds were detected in each sediment sample, and 66 percent of all concentrations were less than the respective interim reporting levels. Halogenated organic compound concentrations were mostly low compared to consensus-based sediment quality guidelines-;TECs were exceeded in 11 percent of the analyses and PECs were exceeded in 1 percent of the analyses. Chlordane compounds were the most frequently detected halogenated organic compounds with one or more detections of chlordane compounds in every watershed; concentrations were greater than the TEC in 6 percent of the samples. Dieldrin was detected in 50 percent of all samples, however all concentrations were much less than the TEC. The DDT compounds (p,p'-DDT, p,p'-DDD, and p,p'-DDE) were detected less frequently than some other halogenated organic compounds, however most detections exceeded the TECs. p,p'-DDT was detected in 13 percent of the samples (TEC exceeded in 67 percent); p,p'-DDD was detected in 19 percent of the samples (TEC exceeded in 78 percent); and p,p'-DDE was detected in 35 percent of the samples (TEC exceeded in 53 percent). p,p'-DDE concentrations in streambed-sediment samples correlate positively with population density and residential, commercial, and transportation land use. One or more PCB congeners were detected in

REMOVAL OF URANIUM FROM ORGANIC LIQUIDS

DOEpatents

Vavalides, S.P.

1959-08-25

A process is described for recovering small quantities of uranium from organic liquids such as hydrocarbon oils. halogen-substituted hydrocarbons, and alcohols. The organic liquid is contacted with a comminuted alkaline earth hydroxide, calcium hydroxide particularly, and the resulting uranium-bearing solid is separated from the liquid by filtration. Uranium may then be recovered from the solid by means of dissolution in nitric acid and conventional extraction with an organic solvent such as tributyl phosphate.

Direct heteroarylation polymerization: guidelines for defect-free conjugated polymers† †Electronic supplementary information (ESI) available. CCDC 1507660 and 1507661. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc00589j Click here for additional data file.

PubMed Central

Bura, Thomas; Beaupré, Serge; Légaré, Marc-André; Quinn, Jesse; Rochette, Etienne; Blaskovits, J. Terence; Fontaine, Frédéric-Georges; Pron, Agnieszka; Li, Yuning

2017-01-01

Direct (hetero)arylation polymerization (DHAP) has emerged as a valuable and atom-economical alternative to traditional cross-coupling methods for the synthesis of low-cost and efficient conjugated polymers for organic electronics. However, when applied to the synthesis of certain (hetero)arene-based materials, a lack of C–H bond selectivity has been observed. To prevent such undesirable side-reactions, we report the design and synthesis of new, bulky, phosphine-based ligands that significantly enhance selectivity of the DHAP process for both halogenated and non-halogenated electron-rich and electron-deficient thiophene-based comonomers. To better understand the selectivity issues, density functional theory (DFT) calculations have been performed on various halogenated and non-halogenated electron-rich and electron-deficient thiophene-based comonomers. Calculations showed that the presence of bromine atoms decreases the energy of activation (E a) of the adjacent C–H bonds, allowing undesirable β-defects for some brominated aromatic units. Both calculations and the new ligands should lead to the rational design of monomers and methods for the preparation of defect-free conjugated polymers from DHAP. PMID:28966781

Linking precious metal enrichment and halogen cycling in mafic magmatic systems: insights from the Rum layered intrusion, NW Scotland

NASA Astrophysics Data System (ADS)

Kelly, A. P.; O'Driscoll, B.; Clay, P. L.; Burgess, R.

2017-12-01

Layered intrusions host the world's largest known concentrations of the platinum-group elements (PGE). Emphasis has been attached to the role of halogen-bearing fluids in concentrating the precious metals, but whether this occurs at the magmatic stage, or via subsequent metasomatism, is actively debated. One obstacle to progress has been the analytical difficulty of measuring low abundances of the halogens in the cumulate products of layered intrusions. To elucidate the importance of the halogens in facilitating PGE-mineralisation, as well as fingerprint halogen provenance and assess the importance of halogen cycling in mafic magma systems more generally, a suite of samples encompassing different stages of activity of the Palaeogene Rum layered intrusion was investigated. Halogen abundances were measured by neutron irradiation noble gas mass spectrometric analysis, permitting the detection of relatively low (ppm-ppb) abundances of Cl, Br and I in mg-sized samples. The samples include PGE-enriched chromite seams, various cumulates (e.g., peridotites), picrites (approximating the Rum parental magma), and pegmatites representing volatile-rich melts that circulated the intrusion at a late-stage in its solidification history. The new data reveal that PGE-bearing chromite seams contain relatively low Cl concentrations (2-3 ppm), with high molar ratios of Br/Cl and I/Cl (0.005 and 0.009, respectively). The picrites and cumulates have Br/Cl and I/Cl ratios close to sub-continental lithospheric mantle values of approximately 0.0013 and 0.00002, respectively, and thus likely reflect the Rum magma source region. A positive correlation between Cl and Br signifies comparable partitioning behaviour in all samples. However, I is more variable, displaying a positive correlation with Cl for more primitive samples (e.g. picrite and peridotite), and seemingly decoupling from Br and Cl in chromite seams and pegmatites. The relative enrichment of I over Cl in the chromite seams points to the local involvement of an organic-rich sedimentary assimilant and potentially represents an important trigger for PGE-mineralisation. Similarly high I/Cl signatures in some of the late-stage pegmatites suggest that fluids with this distinctive composition circulated the cooling Rum intrusion for a protracted period of time.

Sources of halogens in the environment, influences on human and animal health.

PubMed

Fuge, R

1988-06-01

Of the halogens, fluorine has the highest crustal abundance (544 mg/kg) while iodine has the lowest (0.25 mg/kg), however, chlorine is by far the most abundant halogen in the cosmos. The geochemistries of the four naturally occurring halogens have some similarities with fluorine, chlorine and bromine being classified as lithophile elements while iodine is more chalcophile in nature. Bromine and iodine behave in a similar fashion in the secondary environment and could be classified as biophile elements being concentrated in organic matter. Chlorine, bromine and iodine are strongly enriched in the sea while iodine and to a lesser extent bromine are further concentrated in the marine algae.Apart from the occurrence of fluorine in fluorite (CaF2) there are few commonly occurring minerals which contain the halogens as essential constituents. In the igneous environment fluorine and chlorine tend to occupy hydroxyl lattice sites in micas, amphiboles, apatites etc., while in sediments clays can contain appreciable quantities of these elements. Bromine and iodine, however, would be unlikely to fit into the lattice sites of common rock-forming minerals.Bromine, like iodine, is probably volatilised from the marine environment and is carried on to land surfaces. This behaviour of iodine and bromine is reflected in the increased I/CI and Br/CI ratios of surface run-off in continental compared with near coastal environments.Limited information on the soil geochemistry of the halogens suggests that the soil contents of chlorine, bromine and iodine are influenced by proximity to the sea. Soil fluorine, however, is generally dependent on its content in the parent material. In some areas pollutant sources of the halogens contribute appreciably to their concentration in the environment.Iodine and chlorine are essential elements for mammals and fluorine has been shown to have beneficial effects on bone and tooth formation. However, excess quantities of dietary fluorine can be harmful. It is possible, in view of its ubiquitous occurrence in the biosphere, that bromine has a hitherto unknown function in human and animal health.

Organic matrix in produced water from the Osage-Skiatook Petroleum Environmental Research site, Osage County, Oklahoma

USGS Publications Warehouse

Sirivedhin, Tanita; Dallbauman, Liese

2004-01-01

Produced water (water co-produced with oil and gas) constitutes the single largest waste stream for oil and gas industry. Reclaiming this water for beneficial use is thought to be one of the most practical solutions that can solve both environmental and water shortage problems. The feasibility of this practice depends on the ability to remove its chemical content to the levels that meets the appropriate standards. Organic compounds are probably the most difficult fraction to handle. In this paper, the discrete organic compounds and non-volatile, macromolecular organic compounds (i.e., natural organic matter––NOM) of three produced water samples from the Osage-Skiatook Environmental Research site were characterized. Two of the three produced waters had very little contribution from NOM, while one of the samples had about 23% NOM contribution to its organic matrix pool. Fluorescent spectrophotometric scans provided little differentiation among the organic quality of the produced water, while pyrolysis-GC/MS showed that the NOM characteristics of the three produced waters were distinct. Specifically, the overall halogenated content and aromaticity of the NOM were found to be possible qualifiers that distinguish produced water from the coalbed methane well from produced water from the oil well. And the specific chemical fragments that are linked to polysaccharide sources were found to be potential identifiers that distinguish produced water from the newer oil well from produced water from the older oil well. These identifiers were, however, only suggested for this preliminary study. More samples must be included to build a substantial database on produced water NOM to confirm and identify more markers.

Atmosphere-Ocean Coupling through Trace Gases

NASA Astrophysics Data System (ADS)

Tegtmeier, S.; Atlas, E. L.; Krüger, K.; Lennartz, S. T.; Marandino, C. A.; Patra, P. K.; Quack, B.; Schlundt, C.

2017-12-01

Halogen- and sulfur-containing trace gases, as well as other volatile organic compounds (VOCs, such as isoprene) from biogeochemical marine sources are important constituents of the ocean and the atmosphere. These compounds exert wide-ranging influence on atmospheric chemical processes and climate interactions, as well as on human health in coastal regions. In their reactive form, they can affect the oxidizing capacity of the air and lead to the formation of new particles or the growth of existing ones. In this contribution, marine derived halogen-, sulfur-, and oxygen-containing compounds will be discussed. Their net flux into the atmosphere and their impact on atmospheric processes is analyzed based on observations and model simulations.

Method of separating organic contaminants from fluid feedstreams with polyphosphazene membranes

DOEpatents

McCaffrey, Robert R.; Cummings, Daniel G.

1991-01-01

A method is provided for separating halogenated hydrocarbons from a fluid feedstream. The fluid feedstream is flowed across a first surface of a polyphosphazene semipermeable membrane. At least one halogenated hydrocarbon from the fluid feedstream permeates through the polyphosphazene semipermeable membrane to a second opposed surface of the semipermeable membrane. Then the permeated polar hydrocarbon is removed from the second opposed surface of the polyphosphazene semipermeable membrane. Outstanding and unexpected separation selectivities on the order of 10,000 were obtained for methylene chloride when a methylene chloride in water feedstream was flowed across the polyphosphazene semipermeable membrane in the invented method.

Metal-organic scintillator crystals for X-ray, gamma ray, and neutron detection

DOEpatents

Boatner, Lynn A [Oak Ridge, TN; Kolopus, James A [Clinton, TN; Neal, John S [Knoxville, TN; Ramey, Joanne Oxendine [Knoxville, TN; Wisniewski, Dariusz J [Torun, PL

2012-01-03

New metal-organic materials are useful as scintillators and have the chemical formula LX.sub.3(CH.sub.3OH).sub.4 where L is Y, Sc, or a lanthanide element, and X is a halogen element. An example of the scintillator materials is CeCl.sub.3(CH.sub.3OH).sub.4.

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

40 CFR Table 5 to Subpart Hhhhh of... - Emission Limits and Work Practice Standards for Transfer Operations

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Halogenated Group 1 transfer operation vent stream for which you use a combustion device to control organic... your transfer operations. For each . . . You must. . . . 1. Group 1 transfer operation vent stream a... system to any combination of control devices (except a flare); or b. Reduce emissions of total organic...

40 CFR Table 5 to Subpart Hhhhh of... - Emission Limits and Work Practice Standards for Transfer Operations

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Halogenated Group 1 transfer operation vent stream for which you use a combustion device to control organic... your transfer operations. For each . . . You must. . . . 1. Group 1 transfer operation vent stream a... system to any combination of control devices (except a flare); or b. Reduce emissions of total organic...

40 CFR Table 5 to Subpart Hhhhh of... - Emission Limits and Work Practice Standards for Transfer Operations

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Halogenated Group 1 transfer operation vent stream for which you use a combustion device to control organic... your transfer operations. For each . . . You must. . . . 1. Group 1 transfer operation vent stream a... system to any combination of control devices (except a flare); or b. Reduce emissions of total organic...

EMERGING TECHNOLOGY BULLETIN - METHANOTROPHIC BIOREACTOR SYSTEM - BIOTROL, INC.

EPA Science Inventory

BioTrol's Methanotrophic Bioreactor is an above-ground remedial system for water contaminated with halogenated volatile organic compounds, including trichloroethylene (ICE) and related chemicals. Its design features circumvent problems peculiar to treatment of this unique class o...

Cooperativity of halogen, chalcogen, and pnictogen bonds in infinite molecular chains by electronic structure theory.

PubMed

George, Janine; Deringer, Volker L; Dronskowski, Richard

2014-05-01

Halogen bonds (XBs) are intriguing noncovalent interactions that are frequently being exploited for crystal engineering. Recently, similar bonding mechanisms have been proposed for adjacent main-group elements, and noncovalent "chalcogen bonds" and "pnictogen bonds" have been identified in crystal structures. A fundamental question, largely unresolved thus far, is how XBs and related contacts interact with each other in crystals; similar to hydrogen bonding, one might expect "cooperativity" (bonds amplifying each other), but evidence has been sparse. Here, we explore the crucial step from gas-phase oligomers to truly infinite chains by means of quantum chemical computations. A periodic density functional theory (DFT) framework allows us to address polymeric chains of molecules avoiding the dreaded "cluster effects" as well as the arbitrariness of defining a "large enough" cluster. We focus on three types of molecular chains that we cut from crystal structures; furthermore, we explore reasonable substitutional variants in silico. We find evidence of cooperativity in chains of halogen cyanides and also in similar chalcogen- and pnictogen-bonded systems; the bonds, in the most extreme cases, are amplified through cooperative effects by 79% (I···N), 90% (Te···N), and 103% (Sb···N). Two experimentally known organic crystals, albeit with similar atomic connectivity and XB characteristics, show signs of cooperativity in one case but not in another. Finally, no cooperativity is observed in alternating halogen/acetone and halogen/1,4-dioxane chains; in fact, these XBs weaken each other by up to 26% compared to the respective gas-phase dimers.

Dehalogenases: From Improved Performance to Potential Microbial Dehalogenation Applications.

PubMed

Ang, Thiau-Fu; Maiangwa, Jonathan; Salleh, Abu Bakar; Normi, Yahaya M; Leow, Thean Chor

2018-05-07

The variety of halogenated substances and their derivatives widely used as pesticides, herbicides and other industrial products is of great concern due to the hazardous nature of these compounds owing to their toxicity, and persistent environmental pollution. Therefore, from the viewpoint of environmental technology, the need for environmentally relevant enzymes involved in biodegradation of these pollutants has received a great boost. One result of this great deal of attention has been the identification of environmentally relevant bacteria that produce hydrolytic dehalogenases—key enzymes which are considered cost-effective and eco-friendly in the removal and detoxification of these pollutants. These group of enzymes catalyzing the cleavage of the carbon-halogen bond of organohalogen compounds have potential applications in the chemical industry and bioremediation. The dehalogenases make use of fundamentally different strategies with a common mechanism to cleave carbon-halogen bonds whereby, an active-site carboxylate group attacks the substrate C atom bound to the halogen atom to form an ester intermediate and a halide ion with subsequent hydrolysis of the intermediate. Structurally, these dehalogenases have been characterized and shown to use substitution mechanisms that proceed via a covalent aspartyl intermediate. More so, the widest dehalogenation spectrum of electron acceptors tested with bacterial strains which could dehalogenate recalcitrant organohalides has further proven the versatility of bacterial dehalogenators to be considered when determining the fate of halogenated organics at contaminated sites. In this review, the general features of most widely studied bacterial dehalogenases, their structural properties, basis of the degradation of organohalides and their derivatives and how they have been improved for various applications is discussed.

A Base-Resistant Metalloporphyrin Metal–Organic Framework for C–H Bond Halogenation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lv, Xiu-Liang; Wang, Kecheng; Wang, Bin

A base-resistant porphyrin metal–organic framework (MOF), namely PCN-602 has been constructed with 12-connected [Ni 8(OH) 4(H 2O) 2Pz 12] (Pz = pyrazolate) cluster and a newly designed pyrazolate-based porphyrin ligand, 5,10,15,20-tetrakis(4-(pyrazolate-4-yl)phenyl)porphyrin under the guidance of the reticular synthesis strategy. Besides its robustness in hydroxide solution, PCN-602 also shows excellent stability in aqueous solutions of F –, CO 3 2–, and PO 4 3– ions. Interestingly, the Mn 3+-porphyrinic PCN-602, as a recyclable MOF catalyst, presents high catalytic activity for the C–H bond halogenation reaction in a basic system, significantly outperforming its homogeneous counterpart. For the first time, a porphyrinic MOFmore » was thus used as an efficient catalyst in a basic solution with coordinating anions, to the best of our knowledge.« less

A proposal for a test method for assessment of hazard property HP 12 ("Release of an acute toxic gas") in hazardous waste classification - Experience from 49 waste.

PubMed

Hennebert, Pierre; Samaali, Ismahen; Molina, Pauline

2016-12-01

A stepwise method for assessment of the HP 12 is proposed and tested with 49 waste samples. The hazard property HP 12 is defined as "Release of an acute toxic gas": waste which releases acute toxic gases (Acute Tox. 1, 2 or 3) in contact with water or an acid. When a waste contains a substance assigned to one of the following supplemental hazards EUH029, EUH031 and EUH032, it shall be classified as hazardous by HP 12 according to test methods or guidelines (EC, 2014a, 2014b). When the substances with the cited hazard statement codes react with water or an acid, they can release HCl, Cl 2 , HF, HCN, PH 3 , H 2 S, SO 2 (and two other gases very unlikely to be emitted, hydrazoic acid HN 3 and selenium oxide SeO 2 - a solid with low vapor pressure). Hence, a method is proposed:For a set of 49 waste, water addition did not produce gas. Nearly all the solid waste produced a gas in contact with hydrochloric acid in 5 min in an automated calcimeter with a volume >0.1L of gas per kg of waste. Since a plateau of pressure is reached only for half of the samples in 5 min, 6 h trial with calorimetric bombs or glass flasks were done and confirmed the results. Identification of the gases by portable probes showed that most of the tested samples emit mainly CO 2 . Toxic gases are emitted by four waste: metallic dust from the aluminum industry (CO), two air pollution control residue of industrial waste incinerator (H 2 S) and a halogenated solvent (organic volatile(s) compound(s)). HF has not been measured in these trials started before the present definition of HP 12. According to the definition of HP 12, only the H 2 S emission of substances with hazard statement EUH031 is accounted for. In view of the calcium content of the two air pollution control residue, the presence of calcium sulphide (EUH031) can be assumed. These two waste are therefore classified potentially hazardous for HP 12, from a total of 49 waste. They are also classified as hazardous for other properties (HP 7, 10and14 for one of them, and HP 10and14 for the other one respectively). Given these results, it can be assumed that few common household and industrial waste will be classified hazardous only by HP 12. Copyright © 2016 Elsevier Ltd. All rights reserved.

The influence of ocean halogen and sulfur emissions in the air quality of a coastal megacity: The case of Los Angeles.

PubMed

Muñiz-Unamunzaga, Maria; Borge, Rafael; Sarwar, Golam; Gantt, Brett; de la Paz, David; Cuevas, Carlos A; Saiz-Lopez, Alfonso

2018-01-01

The oceans are the main source of natural halogen and sulfur compounds, which have a significant influence on the oxidizing capacity of the marine atmosphere; however, their impact on the air quality of coastal cities is currently unknown. We explore the effect of marine halogens (Cl, Br and I) and dimethyl sulfide (DMS) on the air quality of a large coastal city through a set of high-resolution (4-km) air quality simulations for the urban area of Los Angeles, US, using the Community Multiscale Air Quality (CMAQ model). The results indicate that marine halogen emissions decrease ozone and nitrogen dioxide levels up to 5ppbv and 2.5ppbv, respectively, in the city of Los Angeles. Previous studies suggested that the inclusion of chlorine in air quality models leads to the generation of ozone in urban areas through photolysis of nitryl chloride (ClNO 2 ). However, we find that when considering the chemistry of Cl, Br and I together the net effect is a reduction of surface ozone concentrations. Furthermore, combined ocean emissions of halogens and DMS cause substantial changes in the levels of key urban atmospheric oxidants such as OH, HO 2 and NO 3 , and in the composition and mass of fine particles. Although the levels of ozone, NO 3 and HO x are reduced, we find a 10% increase in secondary organic aerosol (SOA) mean concentration, attributed to the increase in aerosol acidity and sulfate aerosol formation when combining DMS and bromine. Therefore, this new pathway for enhanced SOA formation may potentially help with current model under predictions of urban SOA. Although further observations and research are needed to establish these preliminary conclusions, this first city-scale investigation suggests that the inclusion of oceanic halogens and DMS in air quality models may improve regional air quality predictions over coastal cities around the world. Copyright © 2017 Elsevier B.V. All rights reserved.

METHOD FOR PRODUCING ISOTOPIC METHANES AND PARTIALLY HALOGENATED DERIVATIVES THEROF

DOEpatents

Frazer, J.W.

1959-08-18

A method is given for producing isotopic methanes and/ or partially halogenated derivatives. Lithium hydride, deuteride, or tritide is reacted with a halogenated methane or with a halogenated methane in combination with free halogen. The process is conveniently carried out by passing a halogenated methane preferably at low pressures or in an admixture with an inert gas through a fixed bed of finely divided lithium hydride heated initially to temperatures of 100 to 200 deg C depending upon the halogenated methane used.

Persistent halogenated compounds in aquaculture environments of South China: implications for global consumers' health risk via fish consumption.

PubMed

Yu, Huan-Yun; Zhang, Bao-Zhong; Giesy, John P; Zeng, Eddy Y

2011-10-01

This study examined the potential sources of persistent halogenated compounds (PHCs), including organochlorine pesticides, mainly DDXs (sum of o,p'- and p,p'-DDT, -DDD, and -DDE and p,p'-DDMU) and polybrominated diphenyl ethers, to typical aquaculture environments of South China, determined the relative importance of gill diffusion and fish feeding for exposure of fish to these contaminants and assessed potential health risk for global consumers via consumption of fish from South China. Fish feed is generally a direct and important source of PHCs in both freshwater and seawater aquaculture. In addition, gill diffusion is the predominant uptake route for PHCs (except p,p'-DDMU, o,p'-DDD and -DDT) in farmed freshwater fish, whereas accumulation from the diet is the major route for farmed marine fish. Risks to health of global consumers via consumption of fish from South China are minimal. However, increased risk can be foreseen due to continuous use of brominated fire retardants and electronic waste importation to China. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of persistent trace compounds in landfill gas on engine performance during energy recovery: a case study.

PubMed

Sevimoğlu, Orhan; Tansel, Berrin

2013-01-01

Performances of gas engines operated with landfill gas (LFG) are affected by the impurities in the LFG, reducing the economic viability of energy recovery. The purpose of this study was to characterize the trace compounds in the LFG at the Odayeri Landfill, Istanbul, Turkey which is used for energy recovery. Composite gas samples were collected and analyzed for trace compounds (hydrocarbons, siloxanes, and volatile halogenated hydrocarbons) over a 3-year period. Trace compounds entering the gas engines, their impact on the engine performance were evaluated. The operational problems included deposit formation in the combustion chamber, turbocharger, and intercooler of engine before the scheduled maintenance times. High levels of hydrogen sulfide, as well as chlorinated and fluorinated compounds cause corrosion of the engine parts and decrease life of the engine oils. Persistence of siloxanes results in deposit formation, increasing engine maintenance costs. Pretreatment of LFG is necessary to protect the engines at the waste-to-energy facilities with persistence levels of siloxanes and volatile halogenated hydrocarbons. Copyright © 2012 Elsevier Ltd. All rights reserved.

A PERFORMANCE HISTORY OF THE BASE CATALYZED DECOMPOSITION (BCD) PROCESS

EPA Science Inventory

Remediation of halogenated organic compounds--such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs)--poses a challenge because these compounds are resistant to microbial attack and to degradation by many com...

DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

EPA Science Inventory

The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by–products (DBPs) including total organic halide, trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along ...

International Conference on Environmental Sensing and Assessment, Las Vegas, Nev., September 14-19, 1975, Proceedings. Volumes 1 & 2

NASA Technical Reports Server (NTRS)

1976-01-01

The papers deal with the detection of hazardous environmental pollutants, the development of emission control plans, and the design of compliance monitoring systems. Topics include remote sensing techniques in environmental pollution monitoring, monitoring of atmospheric particulate matter, air pollution due to sulfur dioxide and other inorganic compounds, marine pollution, atmospheric aerosols, industrial pollution, and legal aspects of pollution monitoring. Other papers examine the toxic effects of heavy metals and halogenated hydrocarbons, pollution associated with waste-disposal processes, pesticide residues in soil and groundwater, evaluations of groundwater quality, and monitoring of nuclear wastes. The interaction of climate and pollution is also discussed along with global pollutant transport, environmental modeling, ambient environmental air quality, aircraft and ground-vehicle emissions, and pollution associated with energy extraction and utilization processes. Individual items are announced in this issue.

Regulated and unregulated halogenated disinfection byproduct formation from chlorination of saline groundwater.

PubMed

Szczuka, Aleksandra; Parker, Kimberly M; Harvey, Cassandra; Hayes, Erin; Vengosh, Avner; Mitch, William A

2017-10-01

Coastal utilities exploiting mildly saline groundwater (<150 mg/L chloride) may be challenged by disinfection byproduct (DBP) formation, a concern likely to increase with sea-level rise. Groundwater from North Carolina coastal aquifers is characterized by large variations in concentrations of halides (bromide up to 10,600 μg/L) and dissolved organic carbon (up to 5.7 mg-C/L). Formation of 33 regulated and unregulated halogenated DBPs, including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles, haloacetamides, and haloacetaldehydes, was measured after simulated chlorination of 24 coastal North Carolina groundwater samples under typical chlorination conditions. Results of chlorination simulation show that THM levels exceeded the Primary Maximum Contaminant Levels in half of the chlorinated samples. Addition of halides to a low salinity groundwater (110 mg/L chloride) indicated that elevated bromide triggered DBP formation, but chloride was not a critical factor for their formation. DBP speciation, but not overall molar formation, was strongly correlated with bromide variations in the groundwater. THMs and HAAs dominated the measured halogenated DBPs on a mass concentration basis. When measured concentrations were weighted by metrics of toxic potency, haloacetonitriles, and to a lesser degree, haloacetaldehydes and HAAs, were the predominant contributors to calculated DBP-associated toxicity. For some samples exhibiting elevated ammonia concentrations, the addition of chlorine to form chloramines in situ significantly reduced halogenated DBP concentrations and calculated toxicity. HAAs dominated the calculated toxicity of chloraminated waters. Reverse osmosis treatment of saline groundwater (chloride >250 mg/L) can reduce DBP formation by removing halides and organic precursors. However, we show that in a case where reverse osmosis permeate is blended with a separate raw groundwater, the residual bromide level in the permeate could still exceed that in the raw groundwater, and thereby induce DBP formation in the blend. DBP-associated calculated toxicity increased for certain blends in this system due to the DBPs resulting from the combination of the elevated bromide concentration in the permeate and the organic precursors from the raw coastal groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Situ treatment of contaminated groundwater

DOEpatents

McNab, Jr., Walt W.; Ruiz, Roberto; Pico, Tristan M.

2001-01-01

A system for treating dissolved halogenated organic compounds in groundwater that relies upon electrolytically-generated hydrogen to chemically reduce the halogenated compounds in the presence of a suitable catalyst. A direct current is placed across at least a pair, or an array, of electrodes which are housed within groundwater wells so that hydrogen is generated at the cathode and oxygen at the anode. A pump is located within the well housing in which the cathode(s) is(are) located and draws in groundwater where it is hydrogenated via electrolysis, passes through a well-bore treatment unit, and then transported to the anode well(s) for reinjection into the ground. The well-bore treatment involves a permeable cylinder located in the well bore and containing a packed bed of catalyst material that facilitates the reductive dehalogenation of the halogenated organic compounds by hydrogen into environmentally benign species such as ethane and methane. Also, electro-osmatic transport of contaminants toward the cathode also contributes to contaminant mass removal. The only above ground equipment required are the transfer pipes and a direct circuit power supply for the electrodes. The electrode wells in an array may be used in pairs or one anode well may be used with a plurality of cathode wells. The DC current flow between electrode wells may be periodically reversed which controls the formation of mineral deposits in the alkaline cathode well-bore water, as well as to help rejuvenate the catalysis.

Nontargeted Screening of Halogenated Organic Compounds in Bottlenose Dolphins (Tursiops truncatus) from Rio de Janeiro, Brazil.

PubMed

Alonso, Mariana B; Maruya, Keith A; Dodder, Nathan G; Lailson-Brito, José; Azevedo, Alexandre; Santos-Neto, Elitieri; Torres, Joao P M; Malm, Olaf; Hoh, Eunha

2017-02-07

To catalog the diversity and abundance of halogenated organic compounds (HOCs) accumulating in high trophic marine species from the southwestern Atlantic Ocean, tissue from bottlenose dolphins (Tursiops truncatus) stranded or incidentally captured along the coast of Rio de Janeiro, Brazil, were analyzed by a nontargeted approach based on GC×GC/TOF-MS. A total of 158 individual HOCs from 32 different structural classes were detected in the blubber of 4 adult male T. truncatus. Nearly 90% of the detected compounds are not routinely monitored in the environment. DDT-related and mirex/dechlorane-related compounds were the most abundant classes of anthropogenic origin. Methoxy-brominated diphenyl ethers (MeO-BDEs) and chlorinated methyl- and dimethyl bipyrroles (MBPs and DMBPs) were the most abundant natural products. Reported for the first time in southwestern Atlantic cetaceans and in contrast to North American marine mammals, chlorinated MBPs and DMBPs were more abundant than their brominated and/or mixed halogenated counterparts. HOC profiles in coastal T. truncatus from Brazil and California revealed a distinct difference, with a higher abundance of MeO-BDEs, mirex/dechloranes and chlorinated bipyrroles in the Brazilian dolphins. Thirty-six percent of the detected HOCs had an unknown structure. These results suggest broad geographical differences in the patterns of bioaccumulative chemicals found in the marine environment and indicate the need to develop more complete catalogs of HOCs from various marine environments.

Monoclonal antibodies to cyclodiene insecticides and method for detecting the same

DOEpatents

Stanker, Larry H.; Vanderlaan, Martin; Watkins, Bruce E.

1994-01-01

Methods are described for making specific monoclonal antibodies useful for detection of cyclodienes in foods and environmental samples. Monoclonal antibodies specifically reactive with cyclodienes can detect accumulated pesticides in food, tissue or environmental samples. Extraction and preparation of organic samples for immunoassay in a polar-nonpolar reaction medium permits detection of halogenated organic ring structures at concentrations in samples.

Is There a Need to Discuss Atomic Orbital Overlap When Teaching Hydrogen-Halide Bond Strength and Acidity Trends in Organic Chemistry?

ERIC Educational Resources Information Center

Devarajan, Deepa; Gustafson, Samantha J.; Bickelhaupt, F. Matthias; Ess, Daniel H.

2015-01-01

Undergraduate organic chemistry textbooks and Internet websites use a variety of approaches for presenting and explaining the impact of halogen atom size on trends in bond strengths and/or acidity of hydrogen halides. In particular, several textbooks and Internet websites explain these trends by invoking decreasing orbital overlap between the…

Organic contaminants associated with suspended sediment collected during five cruises of the Mississippi River and its principal tributaries, May 1988 to June 1990

USGS Publications Warehouse

Rostad, Colleen E.; Bishop, LaDonna M.; Ellis, Geoffrey S.; Leiker, Thomas J.; Monsterleet, Stephanie G.; Pereira, Wilfred E.

2004-01-01

Suspended-sediment samples were obtained from sites along the Mississippi River and its principal tributaries to determine the presence of halogenated hydrophobic organic compounds on the suspended sediment smaller than 63 micrometers. Sample collection involved pumping discharge-weighted volumes of river water along a cross section of the river into a continuous-flow centrifuge to isolate the suspended sediment. The suspended sediment was analyzed by gas chromatography/mass spectrometry for pentachlorobenzene, hexachlorobenzene, pentachloroanisole, chlorothalonil, pentachlorophenol, dachthal, chlordane, nonachlor, and penta-, hexa-, hepta-, and octachlorobiphenyls. Samples collected during June 1989 and February-March 1990 also were analyzed for U.S. Environmental Protection Agency priority pollutants, including polycyclic aromatic hydrocarbons, phthalate esters, and triazines. Samples were collected at sites on the Mississippi River from above St. Louis, Missouri to below New Orleans, Louisiana, and on the Illinois, Missouri, Ohio, Wabash, Cumberland, Tennessee, White, Arkansas, and Yazoo Rivers. Masses of selected halogenated hydrophobic organic compounds associated with the suspended sediment at each site are presented in this report in tabular format, along with suspended-sediment concentration, water discharge, and organic-carbon content.

Environmental contamination and human exposure to dioxin-related compounds in e-waste recycling sites of developing countries.

PubMed

Tue, Nguyen Minh; Takahashi, Shin; Subramanian, Annamalai; Sakai, Shinichi; Tanabe, Shinsuke

2013-07-01

E-waste recycling using uncontrolled processes is a major source of dioxin-related compounds (DRCs), including not only the regulated polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) but also non-regulated brominated and mixed halogenated compounds (PBDD/Fs and PXDD/Fs). Various studies at informal e-waste recycling sites (EWRSs) in Asian developing countries found the soil contamination levels of PCDD/Fs from tens to ten thousand picogram TCDD-equivalents (TEQ) per gram and those of DL-PCBs up to hundreds of picogram TEQ per gram. The air concentration of PCDD/Fs was reported as high as 50 pg TEQ per m(3) in Guiyu, the largest Chinese EWRS. Non-regulated compounds also contributed substantially to the total DL toxicity of the DRC mixtures from e-waste, as evidenced by the high TEQ levels estimated for the currently identifiable PBDD/Fs as well as the large portion of unexplained bioassay-derived TEQ levels in soils/dusts from EWRSs. Considering the high exposure levels estimated for EWRS residents, especially children, comprehensive emission inventories of DRCs from informal e-waste recycling, the identities and toxic potencies of unidentified DRCs released, and their impacts on human health need to be investigated in future studies.

The Oxygen Flask Method

ERIC Educational Resources Information Center

Boulton, L. H.

1973-01-01

Discusses application of Schoniger's method of quantitative organic elemental analysis in teaching of qualitative analysis of the halogens, nitrogen, sulphur, and phosphorus. Indicates that the oxygen flask method is safe and suitable for both high school and college courses because of simple apparatus requirements. (CC)

DEMONSTRATION BULLETIN: METAL-ENHANCED ABIOTIC DEGRADATION TECHNOLOGY - ENVIROMETAL TECHNOLOGIES, INC.

EPA Science Inventory

EnviroMetal Technologies, Inc. (ETI), of Guelph, ON, Canada, has developed the metal-enhanced abiotic degradation technology to treat halogenated volatile organic compounds (VOC) in water. A reactive, zero-valent, granular iron medium causes reductive dehalogenation of VOCs yield...

40 CFR 63.2465 - What requirements must I meet for process vents that emit hydrogen halide and halogen HAP or HAP...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Pollutants: Miscellaneous Organic Chemical Manufacturing Emission Limits, Work Practice Standards, and... the mass emission rate of HAP metals based on process knowledge, engineering assessment, or test data...

DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

EPA Science Inventory

The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by-products (DBPS) including total organic halide, trihalomethanes, haloacetic acids, haloacentonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along with ...

Evaluation of Pad 18 Spent Mercury Gold Trap Stainless Steel Container Failure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skidmore, E.

Failure of the Pad 18 spent mercury gold trap stainless steel waste container is principally attributed to corrosion induced by degradation of plasticized polyvinyl chloride (pPVC) waste packaging material. Dehydrochlorination of pPVC polymer by thermal and/or radiolytic degradation is well-known to evolve HCl gas, which is highly corrosive to stainless steel and other metals in the presence of moisture. Degradation of the pPVC packaging material was likely caused by radiolysis in the presence of tritium gas within the waste container, though other degradation mechanisms (aging, thermo-oxidation, plasticizer migration) over 30 years storage may have contributed. Corrosion was also likely enhancedmore » by the crevice in the container weld design, and may have been enhanced by the presence of tritiated water. Similar non-failed spent mercury gold trap waste containers did not show radiographic evidence of plastic packaging or trapped free liquid within the container. Therefore, those containers are not expected to exhibit similar failures. Halogenated polymers such as pPVC subject to degradation can evolve halide gases such as HCl, which is corrosive in the presence of moisture and can generate pressure in sealed systems.« less

Dioxin-like pcb emissions from cement kilns during the use of alternative fuels.

PubMed

Richards, Glen; Agranovski, Igor E

2017-02-05

The substitution of combustion fuels in cement plants is increasing throughout many countries, and its individual performance is constantly assessed against strict regulatory standards. For cement plants within Australia, normal operations remain to use petroleum coal as the dominate energy source at the precalciner, avoiding the opportunity to reduce carbon-based resources and pollutant emissions (such as carbon dioxide, oxides of nitrogen, persistent organic pollutants) whilst providing the necessary energy needs through resource recovery. This paper presents stack emission monitoring of health-critical dl-PCB (dioxin-like polychlorinated biphenyl) congeners during the substitution of alternative fuels at ten Australian cement plants, and to distinguish statistical similarities between other key pollutants (such as polychlorinated dibenzo-p-dioxins and furans (PCDD-F) and hydrogen halogens) and amongst the fuels used. Sampling of plant emissions was performed during normal operations (as baseline trials) and with the varied substitution rates of waste oil, solvents, chipped wood, refuge waste, carbon dust, shredded tyres and black sand (as experimental trials). The extraction of field and analytical data during these trials allowed for determining the total and individual unit mass of dl-PCB and PCDD-F isomers, standardised to 10% O 2 and to World Health Organization (2005) toxicity equivalence (TEQ) values. The findings showed waste co-incineration during cement operations does reduce health-critical congeners of dioxins and dl-PCBs whilst providing the necessary energy and calcination needs. Experimental trials showed all dl-PCBs and PCB TEQ are below the internationally regulated Stockholm Convention article of 10pg TEQ/Nm 3 . In several cases, an increased rate of substituted fuel also identified a consistent reduction to baseline dl-PCBs. The distribution of toxic isomers (TCDD-F and PeCDD-F) were shown to be predominate during waste oil, wood chips, and solvent trials. Whereas the use of TDFs consistently showed a lower toxicity contribution. The distribution of dl-PCBs toxic congeners showed PCB-126 (3,3',4,4',5-Pentachlorobiphenyl) to be greatly present during the co-incineration of waste oil, wood chips, solvents and TDF trials. Principle component analysis identified a statistical predominance from the 1,2,3,7,8-PeCDF (Pentachlorodibenzofuran) and 1,2,3,4,7,8-HxCDF (Hexachlorodibenzofuran) congeners, while dl-PCBs TEQs had similar correlation amongst combustion fuels with major contributions being from the PCB-126 and PCB-169 (3,3',4,4',5,5'-Hexachlorobiphenyl) congeners. Copyright © 2016 Elsevier B.V. All rights reserved.

Biosynthesis of polybrominated aromatic organic compounds by marine bacteria

PubMed Central

Agarwal, Vinayak; El Gamal, Abrahim A.; Yamanaka, Kazuya; Poth, Dennis; Kersten, Roland D.; Schorn, Michelle; Allen, Eric E.; Moore, Bradley S.

2014-01-01

Polybrominated diphenyl ethers (PBDEs) and polybrominated bipyrroles are natural products that bioaccumulate in the marine food chain. PBDEs have attracted widespread attention due to their persistence in the environment and potential toxicity to humans. However, the natural origins of PBDE biosynthesis are not known. Here we report marine bacteria as producers of PBDEs and establish a genetic and molecular foundation for their production that unifies paradigms for the elaboration of bromophenols and bromopyrroles abundant in marine biota. We provide biochemical evidence of marine brominase enzymes revealing decarboxylative-halogenation enzymology previously unknown among halogenating enzymes. Biosynthetic motifs discovered in our study were used to mine sequence databases to discover unrealized marine bacterial producers of organobromine compounds. PMID:24974229

Absolute configuration and crystal packing chirality for three conglomerate-forming ortho-halogen substituted phenyl glycerol ethers

NASA Astrophysics Data System (ADS)

Bredikhin, Alexander A.; Gubaidullin, Aidar T.; Bredikhina, Zemfira A.

2010-06-01

Three conglomerate-forming ortho-Hal (Hal = Cl, Br, I) substituted phenyl glycerol ethers 1- 3 were investigated by single-crystal X-ray analysis, and the absolute configuration for all substances was established. The molecular structures and crystal packing details for halogen derivatives were compared with the same characteristics for ortho-OCH 3 and ortho-CH 3 analogues. Two different types of crystal packing were evaluated for these very much alike compounds. The interplay of the supramolecular crystal organization chirality sense and the single molecule absolute configuration was demonstrated. Some stabilizing and destabilizing interactions involving the ortho-substituents were revealed. The resolution of rac-2 by entrainment procedure was successfully realized.

Transition from metal-ligand bonding to halogen bonding involving a metal as halogen acceptor a study of Cu, Ag, Au, Pt, and Hg complexes

NASA Astrophysics Data System (ADS)

Oliveira, Vytor; Cremer, Dieter

2017-08-01

Utilizing all-electron Dirac-exact relativistic calculations with the Normalized Elimination of the Small Component (NESC) method and the local vibrational mode approach, the transition from metal-halide to metal halogen bonding is determined for Au-complexes interacting with halogen-donors. The local stretching force constants of the metal-halogen interactions reveal a smooth transition from weak non-covalent halogen bonding to non-classical 3-center-4-electron bonding and finally covalent metal-halide bonding. The strongest halogen bonds are found for dialkylaurates interacting with Cl2 or FCl. Differing trends in the intrinsic halogen-metal bond strength, the binding energy, and the electrostatic potential are explained.

Inhalation Cancer Risk Associated with Exposure to Complex Polycyclic Aromatic Hydrocarbon Mixtures in an Electronic Waste and Urban Area in South China

PubMed Central

Wang, Jing; Chen, Shejun; Tian, Mi; Zheng, Xiaobo; Gonzales, Leah; Ohura, Takeshi; Mai, Bixian; Simonich, Staci L. Massey

2012-01-01

Atmospheric particulate matter samples were collected from May 2010 to April 2011 in a rural e-waste area and in Guangzhou, South China, to estimate the lifetime inhalation cancer risk from exposure to parent polycyclic aromatic hydrocarbons (PAHs), high molecular weight PAHs (MW 302 PAHs), and halogenated PAHs (HPAHs). Seasonal variations in the PAH concentrations and profile within and between the e-waste and urban areas indicated different PAH sources in the two areas. Benzo[b]fluoranthene, BaP, dibenz[ah]anthracene, and dibenzo[al]pyrene made the most significant contribution to the inhalation cancer risk. MW 302 PAHs accounting for 18.0% of the total cancer risk in the e-waste area and 13.6% in the urban area, while HPAHs made a minor contribution (< 0.1%) in both the areas. The number of lifetime excess lung cancers due to exposure to parent PAHs, MW 302 PAHs, and HPAHs ranged from 15.1 to 1198 per million people in the e-waste area and from 9.3 to 737 per million people in Guangzhou. PAH exposure accounted for 0.02 to 1.94% of the total lung cancer cases in Guangzhou. On average, the inhalation cancer risk in the e-waste area was 1.6 times higher than in the urban area. The e-waste dismantling activities in South China led to higher inhalation cancer risk due to PAH exposure than the urban area. PMID:22913732

Binding interactions of halogenated bisphenol A with mouse PPARα: In vitro investigation and molecular dynamics simulation.

PubMed

Zhang, Jie; Li, Tiezhu; Wang, Tuoyi; Guan, Tianzhu; Yu, Hansong; Li, Zhuolin; Wang, Yongzhi; Wang, Yongjun; Zhang, Tiehua

2018-02-01

The binding of bisphenol A (BPA) and its halogenated derivatives (halogenated BPAs) to mouse peroxisome proliferator-activated receptor α ligand binding domain (mPPARα-LBD) was examined by a combination of in vitro investigation and in silico simulation. Fluorescence polarization (FP) assay showed that halogenated BPAs could bind to mPPARα-LBD* as the affinity ligands. The calculated electrostatic potential (ESP) illustrated the different charge distributions of halogenated BPAs with altered halogenation patterns. As electron-attracting substituents, halogens decrease the positive electrostatic potential and thereby have a significant influence on the electrostatic interactions of halogenated BPAs with mPPARα-LBD*. The docking results elucidated that hydrophobic and hydrogen-bonding interactions may also contribute to stabilize the binding of the halogenated BPAs to their receptor molecule. Comparison of the calculated binding energies with the experimentally determined affinities yielded a good correlation (R 2 =0.6659) that could provide a rational basis for designing environmentally benign chemicals with reduced toxicities. This work can potentially be used for preliminary screening of halogenated BPAs. Copyright © 2017 Elsevier B.V. All rights reserved.

REDUCTIVE DEHALOGENATION OF HALOMETHANES IN NATURAL AND MODEL SYSTEMS: QSAR ANALYSIS

EPA Science Inventory

Reductive dehalogenation is a dominant reaction pathway for halogenated organics in anoxic environments. Towards the goal of developing predictive tools for this reaction process, the reduction kinetics for a series of halomethanes were measured in batch studies with both natural...

WIDESPREAD OCCURRENCE OF NATURAL HALOGENATED ORGANICS AMONG TEMPERATE MARINE INFAUNA. (R824776)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Tumorigenic effects of dichloroacetic acid in female F344 rats

EPA Science Inventory

Introduction: Dichloroacetic acid (DCA) is a halogenated organic acid produced during oxidant disinfection of drinking water. Prior studies indicate that DCA may increase liver tumors in mice. Here we evaluated the hepatic tumorigenicity of DCA in female rats when given alone ...

Treatment System for Removing Halogenated Compounds from Contaminated Sources

NASA Technical Reports Server (NTRS)

Clausen, Christian A. (Inventor); Yestrebsky, Cherie L. (Inventor); Quinn, Jacqueline W. (Inventor)

2015-01-01

A treatment system and a method for removal of at least one halogenated compound, such as PCBs, found in contaminated systems are provided. The treatment system includes a polymer blanket for receiving at least one non-polar solvent. The halogenated compound permeates into or through a wall of the polymer blanket where it is solubilized with at least one non-polar solvent received by said polymer blanket forming a halogenated solvent mixture. This treatment system and method provides for the in situ removal of halogenated compounds from the contaminated system. In one embodiment, the halogenated solvent mixture is subjected to subsequent processes which destroy and/or degrade the halogenated compound.

Halogenated boron-dipyrromethenes: synthesis, properties and applications.

PubMed

Lakshmi, Vellanki; Rao, Malakalapalli Rajeswara; Ravikanth, Mangalampalli

2015-03-07

Boron-dipyrromethene dyes (BODIPYs) containing halogens at pyrrole carbons are very useful synthons for the synthesis of a variety of BOIDPYs for a wide range of applications. Among the functional groups, halogens are the functional groups which can be regiospecifically introduced at any desired pyrrole carbon of the BODIPY framework by adopting appropriate synthetic strategies. The halogenated BODIPYs can undergo facile nucleophilic substitution reactions to prepare several interesting BODIPY based compounds. This review describes the synthesis, properties and potential applications of halogenated BODIPYs containing one to six halogens at the pyrrole carbons of the BODIPY core as well as properties and applications of some of the substituted BODIPYs derived from halogenated BODIPYs.

Importance of reactive halogens in the tropical marine atmosphere using WRF-chem

NASA Astrophysics Data System (ADS)

Badia, Alba; Reeves, Claire E.; Baker, Alex; Volkamer, Rainer; Apel, Eric; Saiz-Lopez, Alfonso; von Glasow, Roland

2017-04-01

Halogen species (chlorine, bromine and iodine) are known to play an important role in the chemistry and oxidizing capacity of the troposphere, particularly in the marine boundary layer (MBL). Reactive halogens participate in catalytic reaction cycles that efficiently destroy O3, change the HOX and NOX partitioning, affect the oxidation of volatile organic compounds (VOCs) and mercury, reduce the lifetime of methane, and take part in new particle formation. Numerical models predicted that reactive halogen compounds account for 30% of O3 destruction in the MBL and 5-20% globally. Up to 34% of O3 loss in the tropical East Pacific is due to I and Br combined. Recent studies have highlighted the key role that heterogeneous chemistry plays in explaining observations of BrO and IO abundances in the tropical troposphere. The main objective of this study is to investigate the atmospheric chemistry in the tropical East Pacific with a focus on reactive halogens using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and field data from the TORERO campaign. Our reaction mechanism in WRF-Chem is based on the MOZART mechanism and has been extended to include bromine, chlorine and iodine chemistry. Heterogeneous recycling reactions involving sea-salt aerosol and other particles have been included into the model, along with oceanic emissions of important OVOCs and halocarbons. Sea surface emissions of inorganic iodine are calculated using the parameterisation of Carpenter et al., 2013. Focusing on TORERO observations from the ships and a selected number of flights we present the tropospheric impacts of halogens (BrO, IO) in the tropospheric chemistry of relevant species (O3, OH and OVOCS). Sensitivity runs are made in order to study the impact of heterogeneous chemistry in the iodine and bromine species partitioning. A comparison between the online calculation of Very Short Lived Halocarbons (VSLH) oceanic emissions with prescribed oceanic emissions is also presented. Results show that a better performance in O3 concentrations is obtained with the inclusion of halogens. We see a big impact on the Bry partitioning with an improvement of modelled BrO when the heterogeneous chemistry is included. An improvement of our model results is seen when online oceanic emissions are computed.

Monoclonal antibodies to cyclodiene insecticides and method for detecting the same

DOEpatents

Stanker, L.H.; Vanderlaan, M.; Watkins, B.E.

1994-08-02

Methods are described for making specific monoclonal antibodies useful for detection of cyclodienes in foods and environmental samples. Monoclonal antibodies specifically reactive with cyclodienes can detect accumulated pesticides in food, tissue or environmental samples. Extraction and preparation of organic samples for immunoassay in a polar-nonpolar reaction medium permits detection of halogenated organic ring structures at concentrations in samples. 13 figs.

Ionic liquids screening for desulfurization of natural gasoline by liquid-liquid extraction.

PubMed

Likhanova, Natalya V; Guzmán-Lucero, Diego; Flores, Eugenio A; García, Paloma; Domínguez-Aguilar, Marco A; Palomeque, Jorge; Martínez-Palou, Rafael

2010-11-01

Seventy five ionic liquids (ILs) were tested as a sequestering agent of sulfured compounds in natural gasoline (NG). Desulphurization of NG was performed by means of liquid-liquid extraction method at room temperature and atmospheric pressure. Experimental ILs containing imidazolium, pyridinium, and ammonium cations along with organic and inorganic anions were synthesized conventionally and under microwave and sonochemical conditions. The effect of the molecular structure of ILs on the desulfurization efficiency of NG with high sulfur content was evaluated. Analysis indicated that the anion type played a more important role than the cation on the desulphurization process. ILs based on halogen-ferrates and halogen-aluminates exhibited the highest efficiency in sulfur removal, and their efficiency is further improved when there is an excess of metallic salt in a ratio of at least 1:1.3 during the synthesis of the corresponding IL. An explanation for the ability of metallic ILs to remove sulfur-containing compounds from natural gasoline based on the ratio of the ionic charge to the atomic radius is proposed. Furthermore, a method to recover and reuse water-sensitive to halogenated precursors is described.

Assembling supramolecular networks by halogen bonding in coordination polymers driven by 5-bromonicotinic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu, Jin-Zhong, E-mail: gujzh@lzu.edu.cn; Wu, Jiang; Kirillov, Alexander M.

2014-05-01

A series of six coordination compounds ([Zn(5-Brnic){sub 2}]·1.5H{sub 2}O){sub n} (1), [Cd(5-Brnic){sub 2}]{sub n} (2), [Co(5-Brnic){sub 2}(H{sub 2}O){sub 2}]{sub n} (3), [Zn(5-Brnic){sub 2}(H{sub 2}biim)]{sub n} (4), ([Cd(5-Brnic){sub 2}(phen)]·H{sub 2}O){sub n} (5), and [Pb(5-Brnic){sub 2}(phen)] (6) have been generated by the hydrothermal method from the metal(II) nitrates, 5-bromonicotinic acid (5-BrnicH), and an optional ancillary 1,10-phenanthroline (phen) or 2,2′-biimidazole (H{sub 2}biim) ligand. All the products 1–6 have been characterized by IR spectroscopy, elemental, thermal, powder and single-crystal X-ray diffraction analyses. Their 5-bromonicotinate-driven structures vary from the 3D metal-organic framework with the seh-3,5-P21/c topology (in 2) and the 2D interdigitated layers with themore » sql topology (in 1 and 3), to the 1D chains (in 4 and 5) and the 0D discrete monomers (in 6). The 5-bromonicotinate moiety acts as a versatile building block and its tethered bromine atom plays a key role in reinforcing and extending the structures into diverse 3D supramolecular networks via the various halogen bonding Br⋯O, Br⋯Br, and Br⋯π interactions, as well as the N–H⋯O and C–H⋯O hydrogen bonds. The obtained results demonstrate a useful guideline toward engineering the supramolecular architectures in the coordination network assembly under the influence of various halogen bonding interactions. The luminescent (for 1, 2, 4, 5, and 6) and magnetic (for 3) properties have also been studied and discussed in detail. - Graphical abstract: Six coordination compounds driven by 5-bromonicotinic acid have been generated and structurally characterized, revealing diverse metal-organic networks that are further reinforced and extended via various halogen bonding interactions. - Highlights: • 5-Bromonicotinic acid is a versatile ligand for Zn, Cd, Co and Pb derivatives. • Careful selection of co-ligands and metals resulted in different network structures. • Halogen and hydrogen bonding interactions lead to various supramolecular networks. • Luminescent and magnetic properties were studied and discussed in detail.« less

A new class of halogen bonds that avoids the σ-hole

NASA Astrophysics Data System (ADS)

Zhang, Yu; Ma, Ning; Wang, Weizhou

2012-04-01

A new class of halogen bonds of the type X = Hal⋯Y has been investigated by using the density functional theory calculations. The strength of this new class of halogen bonds is in the range of 90-120 kcal/mol, which is greatly larger than that of the conventional halogen bond of the type X-Hal⋯Y. The geometry of this new class of halogen bonds is not determined by the halogen's positive σ-hole. Natural bond orbital analysis shows it is the n → π∗ interaction that determines the geometry of this new class of halogen bonds. Experimental results are in good agreement with the theoretical predictions.

Natural Organohalogens: A New Frontier for Medicinal Agents?

ERIC Educational Resources Information Center

Gribble, Gordon W.

2004-01-01

Newly discovered biogenic organo halogens with an emphasis on the biologically active examples from marine organisms, bacteria, terrestrial plants and higher life forms, including humans, are focused. Organohalogen compounds represent a valuable and expanding class of natural products, in many cases boasting exceptional biological activity.

75 FR 70248 - Endocrine Disruptor Screening Program; Second List of Chemicals for Tier 1 Screening

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-17

...., persons who manufacture, import or process chemical substances. Pesticide, fertilizer, and other... pesticide, fertilizer and agricultural chemicals. Scientific research and development services (NAICS code... water contaminants, such as halogenated organic chemicals, dioxins, flame retardants (PBDEs, PCBs, PFCs...

CAN ABIOTIC (INORGANIC) PROCESSES ACCOUNT FOR HALOACETATE CONCENTRATION PROFILES?

EPA Science Inventory

Haloacetates comprise about 13% of the measurable halogenated organic matter in potable water supplies after chlorination. Some of these species have been linked with animal carcinogenesis and are regulated under the Stage 1 DBP Rule. However, it is known that post-disinfection p...

QSAR ANALYSIS OF SORPTION-CORRECTED RATE CONSTANTS FOR REDUCTIVE BIOTRANSFORMATION OF HALOGENATED AROMATICS

EPA Science Inventory

The inherent coupling among geochemical and microbial reactions may have significant effects on the environmental fate of a containinant. For example, sorption processes may decrease the concentration of an organic compound in solution, thereby reducing the biodegradation rate of...

NATURAL HALOGENATED ORGANIC COMPOUNDS IN MARINE SEDIMENTS ARE FROM POLYCHAETE INDICATOR SPECIES. (R824776)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Health Risk Estimation for Unregulated DBPs in Chloraminated Drinking Water

EPA Science Inventory

Disinfection by-products (DBPs) are formed when natural organic matter (NOM) reacts with chemical oxidants in the water disinfection process. Halogenated DBPs are both cytotoxic and genotoxic, which have the potential to cause adverse health effects (1). Currently, 4 species of t...

Halogenated organic pollutants in marine biota from the Xuande Atoll, South China Sea: Levels, biomagnification and dietary exposure.

PubMed

Sun, Yu-Xin; Hu, Yong-Xia; Zhang, Zai-Wang; Xu, Xiang-Rong; Li, Heng-Xiang; Zuo, Lin-Zi; Zhong, Yi; Sun, Hong; Mai, Bi-Xian

2017-05-15

Six marine biota species were collected from the Xuande Atoll, South China Sea to investigate the bioaccumulation of dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and dechlorane plus (DP). Pike conger (Muraenesox talabonoides) had the highest concentrations of halogenated organic pollutants (HOPs) among the six marine biota species. DDTs were the predominant HOPs, followed by PCBs and PBDEs, with minor contributions of DBDPE and DP. Twenty-one percent of samples had ratios of (DDE+DDD)/ΣDDTs lower than 0.5, implying the presence of fresh DDT inputs in the environment of the Xuande Atoll. The biomagnification factor values for DDTs, PCBs, PBDEs and DP were higher than 1, suggesting biomagnification of these contaminants in the marine food chains. Consumption of seafood from the Xuande Atoll might not subject local residents in the coastal areas of South China to health risks as far as HOPs are concerned. Copyright © 2017 Elsevier Ltd. All rights reserved.

Contamination of estuarine water, biota, and sediment by halogenated organic compounds: A field study

USGS Publications Warehouse

Pereira, W.E.; Rostad, C.E.; Chiou, C.T.; Brinton, T.I.; Barber, L.B.; Demcheck, D.K.; Demas, C.R.

1988-01-01

Studies conducted in the vicinity of an industrial outfall in the Calcasieu River estuary, Louisiana, have shown that water, bottom and suspended sediment, and four different species of biota are contaminated with halogenated organic compounds (HOC) including haloarenes. A "salting-out" effect in the estuary moderately enhanced the partitioning tendency of the contaminants into biota and sediments. Contaminant concentrations in water, suspended sediments, and biota were found to be far below the values predicted on the basis of the assumption of phase equilibria with respect to concentrations in bottom sediment. Relative concentration factors of HOC between biota (catfish) and bottom sediment increased with increasing octanol/estuarine water partition coefficients (Kow*), maximizing at log Kow* of about 5, although these ratios were considerably less than equilibrium values. In contrast, contaminant concentrations in water, biota, and suspended sediments were much closer to equilibrium values. Bioconcentration factors of HOC determined on the basis of lipid content for four different biotic species correlated reasonably well with equilibrium triolein/water partition coefficients (Ktw).

Method of dehalogenation using diamonds

DOEpatents

Farcasiu, Malvina; Kaufman, Phillip B.; Ladner, Edward P.; Anderson, Richard R.

2000-01-01

A method for preparing olefins and halogenated olefins is provided comprising contacting halogenated compounds with diamonds for a sufficient time and at a sufficient temperature to convert the halogenated compounds to olefins and halogenated olefins via elimination reactions.

NTP Renal Toxicity Studies of Selected Halogenated Ethanes Administered by Gavage to F344/N Rats.

PubMed

1996-02-01

The National Cancer Institute and National Toxicology Program have performed 2-year toxicology and carcinogenesis studies with a number of ethanes substituted with chlorine or bromine. A review of the results of studies with these halogenated ethanes has revealed several consistencies between the pattern of halogen substitution and neoplastic responses in some affected organs. One of these consistencies was the finding of a modest increase in the incidence of renal tubule cell neoplasms in male rats administered penta- or hexachloroethane. Certain aspects of the nephropathy also noted in these studies resembled what is now recognized as a distinct hyaline droplet nephropathy typically associated with the accumulation of alpha[alpha]2&mgr;-globulin in renal tubule cells. In an attempt to determine some of the structure activity relationships involved in the induction of hyaline droplet nephropathy by halogenated ethanes, a series of commercially available ethanes substituted with three or more chlorines, four or more bromines, or a combination of chlorines and fluorines was studied in a short-term renal toxicity assessment in male F344/N rats. All chemicals were administered by gavage in corn oil to groups of five male rats once daily for 21 days. The doses selected for study, 0.62 and 1.24 mmol/kg per day, were based on those used in the 2-year pentachloroethane studies. The following chemicals were evaluated: 1,1,1,2- and 1,1,2,2-tetrachloroethane; pentachloroethane; 1,1,2,2-tetrachloro1,2-difluoroethane; 1,1,1-trichloro-2,2,2-trifluoroethane; 1,2-dichloro-1,1-difluoroethane; 1,1,1-trichloroethane; hexachloroethane; 1,1,1,2-and 1,1,2,2-tetrabromoethane; and pentabromoethane. Evaluations included survival, mean body weight gains, clinical signs, organ weights, urinalysis, and histopathologic examination of the right kidney and liver. The kidneys of rats that showed a difference in renal protein droplet accumulation compared to the controls were evaluated for replicative DNA synthesis by staining for proliferating cell nuclear antigen. For most groups, survival was not affected by chemical treatment; however, all rats administered either dose of 1,1,2,2-tetrabromoethane died by Day 11, and all rats administered 1.24 mmol/kg pentabromoethane, 1,1,1,2-tetrabromoethane, or 1,1,2,2-tetrachloroethane died before the end of the study. Rats receiving 0.62 mmol/kg pentabromoethane gained less weight than the controls, and rats in the 0.62 mmol/kg 1,1,1,2-tetrabromoethane group lost weight during the study. Increased kidney weights and signs of renal toxicity, indicated by urinalysis results, were noted in rats in many of the groups administered halogenated ethanes, but these observations were not always coincident with a diagnosis of hyaline droplet nephropathy. Hyaline droplet nephropathy was observed only in rats receiving penta-, hexa-, or 1,1,1,2-tetrachloroethane. The renal tubule cell labeling index was increased, indicating replicative DNA synthesis, in male rats receiving chemicals that induced hyaline droplet nephropathy as well as in males receiving pentabromoethane or 1,1,2,2-tetrachloroethane and in female negative control rats administered pentachloroethane; thus some of the halogenated ethanes appeared to cause significant renal toxicity not associated with hyaline droplet nephropathy. In summary, of the halogenated ethanes studied, the capacity to induce hyaline droplet nephropathy in male rats was restricted to ethanes containing four or more halogens, and only the chlorinated ethanes were active. If the ability to induce hyaline droplet nephropathy is the determining factor in the induction of renal tubule cell neoplasms by halogenated ethanes, then an absence of kidney neoplasms in male rats would be predicted in the event that 2-year studies were performed with the bromo- or chlorofluoroethanes.

The contribution of hydrothermally altered ocean crust to the mantle halogen and noble gas cycles

NASA Astrophysics Data System (ADS)

Chavrit, Déborah; Burgess, Ray; Sumino, Hirochika; Teagle, Damon A. H.; Droop, Giles; Shimizu, Aya; Ballentine, Chris J.

2016-06-01

Recent studies suggest that seawater-derived noble gases and halogens are recycled into the deep mantle by the subduction of oceanic crust. To understand the processes controlling the availability of halogens and noble gases for subduction, we determined the noble gas elemental and isotopic ratios and halogen (Cl, Br, I) concentrations in 28 igneous samples from the altered oceanic crust (AOC) from 5 ODP sites in the Eastern and Western Pacific Ocean. Crushing followed by heating experiments enabled determination of noble gases and halogens in fluid inclusions and mineral phases respectively. Except for He and Ar, Ne, Kr and Xe isotopic ratios were all air-like suggesting that primary MORB signatures have been completely overprinted by air and/or seawater interaction. In contrast, 3He/4He ratios obtained by crushing indicate that a mantle helium component is still preserved, and 40Ar/36Ar values are affected by radiogenic decay in the mineral phases. The 130Xe/36Ar and 84Kr/36Ar ratios are respectively up to 15 times and 5 times higher than those of seawater and the highest ratios are found in samples affected by low temperature alteration (shallower than 800-900 m sub-basement). We consider three possible processes: (i) adsorption onto the clays present in the samples; (ii) fluid inclusions with a marine pore fluid composition; and (iii) fractionation of seawater through phase separation caused by boiling. Ninety percent of the Cl, Br and I were released during the heating experiments, showing that halogens are dominantly held in mineral phases prior to subduction. I/Cl ratios vary by 4 orders of magnitude, from 3 × 10-6 to 2 × 10-2. The mean Br/Cl ratio is 30% lower than in MORB and seawater. I/Cl ratios lower than MORB values are attributed to Cl-rich amphibole formation caused by hydrothermal alteration at depths greater than 800-900 m sub-basement together with different extents of I loss during low and high temperature alteration. At shallower depths, I/Cl ratios higher than MORB values can be explained by the addition of organic-rich sediments or the presence of organic detritus, both known to efficiently sequester I. Concentrations of 36Ar of the pre-subducting materials are sufficient to account for the 36Ar and composition of the mantle in the context of existing subduction-flux models. We find the Cl subduction flux of the oceanic crust to be about three times higher than the previous estimates and that sufficient Cl and Br can potentially be delivered by subduction over the last 3 Ga to account for mantle source compositions.

Method of producing nano-scaled graphene and inorganic platelets and their nanocomposites

DOEpatents

Jang, Bor Z [Centerville, OH; Zhamu, Aruna [Centerville, OH

2011-02-22

Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets. Alternatively, rather than heating, step (a) is followed by a step of dispersing the halogen-intercalated compound in a liquid medium which is subjected to ultrasonication for exfoliating the halogen-intercalated compound to produce the platelets, which are dispersed in the liquid medium. The halogen can be readily captured and re-used, thereby significantly reducing the impact of halogen to the environment. The method can further include a step of dispersing the platelets in a polymer or monomer solution or suspension as a precursor step to nanocomposite fabrication.

Method of producing nano-scaled graphene and inorganic platelets and their nanocomposites

DOEpatents

Jang, Bor Z [Centerville, OH; Zhamu, Aruna [Centerville, OH

2012-02-14

Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets. Alternatively, rather than heating, step (a) is followed by a step of dispersing the halogen-intercalated compound in a liquid medium which is subjected to ultrasonication for exfoliating the halogen-intercalated compound to produce the platelets, which are dispersed in the liquid medium. The halogen can be readily captured and re-used, thereby significantly reducing the impact of halogen to the environment. The method can further include a step of dispersing the platelets in a polymer or monomer solution or suspension as a precursor step to nanocomposite fabrication.

Particle formation above natural and simulated salt lakes

NASA Astrophysics Data System (ADS)

Kamilli, Katharina; Ofner, Johannes; Sattler, Tobias; Krause, Torsten; Zetzsch, Cornelius; Held, Andreas

2013-04-01

Western Australia was originally covered by natural eucalyptus forests, but land-use has changed considerably after large scale deforestation from 1950 to 1970. Thus, the ground-water level rose and brought dissolved salts and minerals to the surface. Nowadays, Western Australia is known for a great plenty of salt lakes with pH levels reaching from 2.5 to 7.1. The land is mainly used for wheat farming and livestock and becomes drier due to the lack of rain periods. One possible reason could be the formation of ultrafine particles from salt lakes, which increases the number of cloud condensation nuclei and thus potentially suppresses precipitation. Several field campaigns have been conducted between 2006 and 2011 with car-based and airborne measurements, where new particle formation has been observed and has been related to the Western Australian salt lakes (Junkermann et al., 2009). To identify particle formation directly above the salt lakes, a 1.5 m³ Teflon chamber was set up above several lakes in 2012. Inside the chamber, photochemistry may take place whereas mixing through wind or advection of already existing particles is prevented. Salt lakes with a low pH level lead to strongly increased aerosol formation. As salt lakes have been identified as a source for reactive halogen species (RHS; Buxmann et al., 2012) and RHS seem to interact with precursors of secondary organic aerosol (SOA), they could be producers of halogen induced secondary organic aerosol (XOA) (Ofner et al., 2012). As reference experiments, laboratory based aerosol smog-chamber runs were performed to examine XOA formation under atmospheric conditions using simulated sunlight and the chemical composition of a chosen salt lake. After adding α-pinene to the simulated salt lake, a strong nucleation event began in the absence of ozone comparable to the observed events in Western Australia. First results from the laboratory based aerosol smog-chamber experiments indicate a halogen-induced aerosol formation above Australian salt lakes. This work was funded by German Research Foundation (DFG) under grants HE 5214/5-1 and ZE792/5-2. References: Buxmann, J., Balzer, N., Bleicher, S., Platt, U., and Zetzsch, C.: Observations of bromine explosions in smog chamber experiments above a model salt pan, Int. J. Chem. Kinet., 44, 312-326, 2012. Junkermann, W., Hacker, J., Lyons, T., and Nair, U.: Land use change suppresses precipitation, Atmos. Chem. Phys., 9, 6531-6539, 2009. Ofner, J., Balzer, N., Buxmann, J., Grothe, H., Schmitt-Kopplin, Ph., Platt, U., and Zetzsch, C.: Halogenation processes of secondary organic aerosol and implications on halogen release mechanisms, Atmos. Chem. Phys., 12, 5787-5806, 2012.

Toxic effects of butyl elastomers on aerobic methane oxidation

NASA Astrophysics Data System (ADS)

Niemann, Helge; Steinle, Lea I.; Blees, Jan H.; Krause, Stefan; Bussmann, Ingeborg; Lehmann, Moritz F.; Treude, Tina

2013-04-01

Large quantities of the potent greenhouse gas methane are liberated into the water column of marine and lacustrine environments where it may be consumed by aerobic methane oxidising bacteria before reaching the atmosphere.The reliable quantification of aerobic methane oxidation (MOx) rates is consequently of paramount importance for estimating methane budgets and to understand the controls on water column methane cycling. A widely used set of methods for measuring MOx rates is based on the incubation of water samples during which the consumption of methane is monitored, for instance with radio-tracer assays. Typically, incubation vessels are sealed with butyl rubber stoppers because these elastomers are essentially impermeable for gases at the relevant time scales. We tested the effect of different stopper materials (unmodified- and halogenated butyl rubber) on MOx activity in environmental samples and in cultures of methane oxidising bacteria. MOx rates in samples sealed with unmodified butyl rubber were > 75% lower compared to parallel incubations with halogenated butyl rubber seals, suggesting inhibiting/toxic effects associated with the use of unmodified butyl elastomers. To further explore the cause of these effects, we analysed aqueous extracts of the different stoppers. Halogenated butyl rubber stoppers appeared to bleed off comparably little amounts of organics. In stark contrast, extracts of unmodified butyl rubber were contaminated with various organic compounds including potential bactericides such as benzyltoluenes, phenylalkanes and benzuothiazoles. We also found tetramethylthiourea, a scavenger of active oxygen species, which may inhibit the MOx pathway.

Volatile organic compounds in stormwater from a community of Beijing, China.

PubMed

Li, Haiyan; Wang, Youshu; Liu, Fei; Tong, Linlin; Li, Kun; Yang, Hua; Zhang, Liang

2018-08-01

Stormwater samples were collected from six different land use sites with three time-intervals during a precipitation event on August 12, 2016, from a community of Beijing, China. A total of 46 species volatile organic compounds (VOCs) were detected in these stormwater samples, including methyl tertiary-butyl ether (MTBE), aromatic hydrocarbons, halogenated aromatics, Halogenated alkanes, and alkenes. The total VOC concentrations varied in the six sites following order: highway junction > city road > gas station > park > campus > residential area, except for MTBE, which was much higher at gas station compared to other land use sites. ANOVA results indicated both land use and precipitation time intervals could significantly affect the VOC concentrations even in the small area. The Beijing atmospheric VOC concentrations were too low to explain the high concentrations in stormwater, suggesting that land surfaces may be the main sources of VOC other than the ambient atmosphere. MTBE and other VOCs correlation analysis indicated that MTBE mostly came from gasoline emissions, spills or vehicle exhausts, whereas the BTEX (benzene, toluene, ethylbenzene, Xylenes) and the halogenated aromatics were transferred from chemical plants through land surfaces accumulating and the wind blowing atmospheric VOCs. Xylenes/ethylbenzene (X/E) ratios variations indicated that stormwater incorporated larger amount of fresh emitted air during the precipitation event than prior to it. Information of these stormwater VOCs in this study could be used in the community pollution reduction strategies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modulation of persistent organic pollutant toxicity through nutritional intervention: emerging opportunities in biomedicine and environmental remediation.

PubMed

Petriello, Michael C; Newsome, Bradley J; Dziubla, Thomas D; Hilt, J Zach; Bhattacharyya, Dibakar; Hennig, Bernhard

2014-09-01

Environmental pollution is increasing worldwide, and there is evidence that exposure to halogenated persistent organic pollutants (POPs) such as polychlorinated biphenyls can contribute to the pathology of inflammatory diseases such as atherosclerosis, diabetes, and cancer. Pollutant removal from contaminated sites and subsequent pollutant degradation are critical for reducing the long-term health risks associated with exposure. However, complete remediation of a toxicant from the environment is very difficult and cost-prohibitive. Furthermore, remediation technologies often result in the generation of secondary toxicants. Considering these circumstances, environmentally-friendly and sustainable remediation technologies and biomedical solutions to reduce vulnerability to environmental chemical insults need to be explored to reduce the overall health risks associated with exposure to environmental pollutants. We propose that positive lifestyle changes such as healthful nutrition and consumption of diets rich in fruits and vegetables or bioactive nutrients with antioxidant and/or anti-inflammatory properties will reduce the body's vulnerability to environmental stressors and thus reduce toxicant-mediated disease pathologies. Interestingly, emerging evidence now implicates the incorporation of bioactive nutrients, such as plant-derived polyphenols, in technologies focused on the capture, sensing and remediation of halogenated POPs. We propose that human nutritional intervention in concert with the use of natural polyphenol sensing and remediation platforms may provide a sensible means to develop primary and long-term prevention strategies of diseases associated with many environmental toxic insults including halogenated POPs. Copyright © 2014 Elsevier B.V. All rights reserved.

Modulation of persistent organic pollutant toxicity through nutritional intervention: emerging opportunities in biomedicine and environmental remediation

PubMed Central

Petriello, Michael C.; Newsome, Bradley J.; Dziubla, Thomas D.; Hilt, J. Zach; Bhattacharyya, Dibakar; Hennig, Bernhard

2014-01-01

Environmental pollution is increasing worldwide, and there is evidence that exposure to halogenated persistent organic pollutants (POPs) such as polychlorinated biphenyls can contribute to the pathology of inflammatory diseases such as atherosclerosis, diabetes, and cancer. Pollutant removal from contaminated sites and subsequent pollutant degradation are critical for reducing the long-term health risks associated with exposure. However, complete remediation of a toxicant from the environment is very difficult and cost-prohibitive. Furthermore, remediation technologies often result in the generation of secondary toxicants. Considering these circumstances, environmentally-friendly and sustainable remediation technologies and biomedical solutions to reduce vulnerability to environmental chemical insults need to be explored to reduce the overall health risks associate with exposure to environmental pollutants. We propose that positive lifestyle changes such as healthful nutrition and consumption of diets rich in fruits and vegetables or bioactive nutrients with antioxidant and/or anti-inflammatory properties will reduce the body’s vulnerability to environmental stressors and thus reduce toxicant-mediated disease pathologies. Interestingly, emerging evidence now implicates the incorporation of bioactive nutrients, such as plant-derived polyphenols, in technologies focused on the capture, sensing and remediation of halogenated POPs. We propose that human nutritional intervention in concert with the use of natural polyphenol sensing and remediation platforms may provide a sensible means to develop primary and long-term prevention strategies of diseases associated with many environmental toxic insults including halogenated POPs. PMID:24530186

Independent Evolution of Six Families of Halogenating Enzymes.

PubMed

Xu, Gangming; Wang, Bin-Gui

2016-01-01

Halogenated natural products are widespread in the environment, and the halogen atoms are typically vital to their bioactivities. Thus far, six families of halogenating enzymes have been identified: cofactor-free haloperoxidases (HPO), vanadium-dependent haloperoxidases (V-HPO), heme iron-dependent haloperoxidases (HI-HPO), non-heme iron-dependent halogenases (NI-HG), flavin-dependent halogenases (F-HG), and S-adenosyl-L-methionine (SAM)-dependent halogenases (S-HG). However, these halogenating enzymes with similar biological functions but distinct structures might have evolved independently. Phylogenetic and structural analyses suggest that the HPO, V-HPO, HI-HPO, NI-HG, F-HG, and S-HG enzyme families may have evolutionary relationships to the α/β hydrolases, acid phosphatases, peroxidases, chemotaxis phosphatases, oxidoreductases, and SAM hydroxide adenosyltransferases, respectively. These halogenating enzymes have established sequence homology, structural conservation, and mechanistic features within each family. Understanding the distinct evolutionary history of these halogenating enzymes will provide further insights into the study of their catalytic mechanisms and halogenation specificity.

Evaluating the potential for halogen bonding in ketosteroid isomerase’s oxyanion hole using unnatural amino acid mutagenesis

PubMed Central

Kraut, Daniel A; Churchil, Michael J; Dawson, Phillip E

2009-01-01

There has recently been an increasing interest in controlling macromolecular conformations and interactions through halogen bonding. Halogen bonds are favorable electrostatic interactions between polarized, electropositive chlorine, bromine or iodine atoms and electronegative atoms such as oxygen or nitrogen. These interactions have been likened to hydrogen bonds both in terms of their favored acceptor molecules, their geometries, and their energetics. We asked whether a halogen bond could replace a hydrogen bond in the oxyanion hole of ketosteroid isomerase, using semi-synthetic enzyme containing para-halogenated phenylalanine derivatives to replace the tyrosine hydrogen bond donor. Formation of a halogen bond to the oxyanion in the transition state would be expected to rescue the effects of mutation to phenylalanine, but all of the halogenated enzymes were comparable in activity to the phenylalanine mutant. We conclude that, at least in this active site, a halogen bond cannot functionally replace a hydrogen bond. PMID:19260691

L-alanine-glyoxylate aminotransferase II of rat kidney and liver mitochondria possesses cysteine S-conjugate beta-lyase activity: a contributing factor to the nephrotoxicity/hepatotoxicity of halogenated alkenes?

PubMed Central

Cooper, Arthur J L; Krasnikov, Boris F; Okuno, Etsuo; Jeitner, Thomas M

2003-01-01

Several halogenated alkenes are metabolized in part to cysteine S-conjugates, which are mitochondrial toxicants of kidney and, to a lesser extent, other organs. Toxicity is due to cysteine S-conjugate beta-lyases, which convert the cysteine S-conjugate into pyruvate, ammonia and a reactive sulphur-containing fragment. A section of the human population is exposed to halogenated alkenes. To understand the health effects of such exposure, it is important to identify cysteine S-conjugate beta-lyases that contribute to mitochondrial damage. Mitochondrial aspartate aminotransferase [Cooper, Bruschi, Iriarte and Martinez-Carrion (2002) Biochem. J. 368, 253-261] and mitochondrial branched-chain aminotransferase [Cooper, Bruschi, Conway and Hutson (2003) Biochem. Pharmacol. 65, 181-192] exhibit beta-lyase activity toward S -(1,2-dichlorovinyl)-L-cysteine (the cysteine S-conjugate of trichloroethylene) and S -(1,1,2,2-tetrafluoroethyl)-L-cysteine (the cysteine S-conjugate of tetrafluoroethylene). Turnover leads to eventual inactivation of these enzymes. Here we report that mitochondrial L-alanine-glyoxylate aminotransferase II, which, in the rat, is most active in kidney, catalyses cysteine S-conjugate beta-lyase reactions with S -(1,1,2,2-tetrafluoroethyl)-L-cysteine, S -(1,2-dichlorovinyl)-L-cysteine and S -(benzothiazolyl-L-cysteine); turnover leads to inactivation. Previous workers showed that the reactive-sulphur-containing fragment released from S -(1,1,2,2-tetrafluoroethyl)-L-cysteine and S -(1,2-dichlorovinyl)-L-cysteine is toxic by acting as a thioacylating agent - particularly of lysine residues in nearby proteins. Toxicity, however, may also involve 'self-inactivation' of key enzymes. The present findings suggest that alanine-glyoxylate aminotransferase II may be an important factor in the well-established targeting of rat kidney mitochondria by toxic halogenated cysteine S-conjugates. Previous reports suggest that alanine-glyoxylate aminotransferase II is absent in some humans, but present in others. Alanine-glyoxylate aminotransferase II may contribute to the bioactivation (toxification) of halogenated cysteine S-conjugates in a subset of individuals exposed to halogenated alkenes. PMID:12859250

Chemoselective Radical Dehalogenation and C-C Bond Formation on Aryl Halide Substrates Using Organic Photoredox Catalysts.

PubMed

Poelma, Saemi O; Burnett, G Leslie; Discekici, Emre H; Mattson, Kaila M; Treat, Nicolas J; Luo, Yingdong; Hudson, Zachary M; Shankel, Shelby L; Clark, Paul G; Kramer, John W; Hawker, Craig J; Read de Alaniz, Javier

2016-08-19

Despite the number of methods available for dehalogenation and carbon-carbon bond formation using aryl halides, strategies that provide chemoselectivity for systems bearing multiple carbon-halogen bonds are still needed. Herein, we report the ability to tune the reduction potential of metal-free phenothiazine-based photoredox catalysts and demonstrate the application of these catalysts for chemoselective carbon-halogen bond activation to achieve C-C cross-coupling reactions as well as reductive dehalogenations. This procedure works both for conjugated polyhalides as well as unconjugated substrates. We further illustrate the usefulness of this protocol by intramolecular cyclization of a pyrrole substrate, an advanced building block for a family of natural products known to exhibit biological activity.

Insights into enzymatic halogenation from computational studies

PubMed Central

Senn, Hans M.

2014-01-01

The halogenases are a group of enzymes that have only come to the fore over the last 10 years thanks to the discovery and characterization of several novel representatives. They have revealed the fascinating variety of distinct chemical mechanisms that nature utilizes to activate halogens and introduce them into organic substrates. Computational studies using a range of approaches have already elucidated many details of the mechanisms of these enzymes, often in synergistic combination with experiment. This Review summarizes the main insights gained from these studies. It also seeks to identify open questions that are amenable to computational investigations. The studies discussed herein serve to illustrate some of the limitations of the current computational approaches and the challenges encountered in computational mechanistic enzymology. PMID:25426489

Chemical Characterization of Dissolved Organic Matter (DOM) in Seawater: Structure, Cycling and the Role of Biology

DTIC Science & Technology

2005-02-01

concentration, excluding hydrocarbons , was less than 2% of the total organic carbon present in the samples, and the samples had not been pre-extracted to...carbon chains that make up the separation phase of the C18 134 column. This carbon chain was most likely generated from petroleum products, and had a...produced, bioaccumulating halogenated organic compound. Environmental Science and Technology 38: 1992-1997. Silfer, J. A., M. H. Engel and S. A

THE FATE OF THE HALOACETATES IN DRINKING WATER - CHEMICAL KINETICS IN AQUEOUS SOLUTION

EPA Science Inventory

Haloacetates comprise about 13% of the measurable halogenated organic matter in potable water supplies after chlorination. Some of these species have been linked with animal carcinogenesis and are regulated under the Stage 1 Disinfection Byproduct (DBP) Rule. However, it is known...

Metal complexes of substituted Gable porphyrins as oxidation catalysts

DOEpatents

Lyons, James E.; Ellis, Jr., Paul E.; Wagner, Richard W.

1996-01-01

Transition metal complexes of Gable porphyrins having two porphyrin rings connected through a linking group, and having on the porphyrin rings electron-withdrawing groups, such as halogen, nitro or cyano. These complexes are useful as catalysts for the oxidation of organic compounds, e.g. alkanes.

Passivation of quartz for halogen-containing light sources

DOEpatents

Falkenstein, Zoran

1999-01-01

Lifetime of halogen containing VUV, UV, visible or IR light sources can be extended by passivating the quartz or glass gas containers with halogens prior to filling the quartz with the halogen and rare gas mixtures used to produce the light.

Method and apparatus for low temperature destruction of halogenated hydrocarbons

DOEpatents

Reagen, William Kevin; Janikowski, Stuart Kevin

1999-01-01

A method and apparatus for decomposing halogenated hydrocarbons are provided. The halogenated hydrocarbon is mixed with solvating agents and maintained in a predetermined atmosphere and at a predetermined temperature. The mixture is contacted with recyclable reactive material for chemically reacting with the recyclable material to create dehalogenated hydrocarbons and halogenated inorganic compounds. A feature of the invention is that the process enables low temperature destruction of halogenated hydrocarbons.

Halogen lamp experiment, HALEX

NASA Technical Reports Server (NTRS)

Schmitt, G.; Stapelmann, J.

1986-01-01

The main purpose of the Halogen Lamp Experiment (HALEX) was to investigate the operation of a halogen lamp during an extended period in a microgravity environment and to prove its behavior in space. The Mirror Heating Facilities for Crystal Growth and Material Science Experiments in space relies on one or two halogen lamps as a furnace to melt the specimens. The HALEX aim is to verify: full power operation of a halogen lamp for a period of about 60 hours; achievement of about 10% of its terrestrial life span; and operation of the halogen lamp under conditions similar to furnace operation.

The Important Role of Halogen Bond in Substrate Selectivity of Enzymatic Catalysis

NASA Astrophysics Data System (ADS)

Jiang, Shuiqin; Zhang, Lujia; Cui, Dongbin; Yao, Zhiqiang; Gao, Bei; Lin, Jinping; Wei, Dongzhi

2016-10-01

The use of halogen bond is widespread in drug discovery, design, and clinical trials, but is overlooked in drug biosynthesis. Here, the role of halogen bond in the nitrilase-catalyzed synthesis of ortho-, meta-, and para-chlorophenylacetic acid was investigated. Different distributions of halogen bond induced changes of substrate binding conformation and affected substrate selectivity. By engineering the halogen interaction, the substrate selectivity of the enzyme changed, with the implication that halogen bond plays an important role in biosynthesis and should be used as an efficient and reliable tool in enzymatic drug synthesis.

Halogen bonding in solution: thermodynamics and applications.

PubMed

Beale, Thomas M; Chudzinski, Michael G; Sarwar, Mohammed G; Taylor, Mark S

2013-02-21

Halogen bonds are noncovalent interactions in which covalently bound halogens act as electrophilic species. The utility of halogen bonding for controlling self-assembly in the solid state is evident from a broad spectrum of applications in crystal engineering and materials science. Until recently, it has been less clear whether, and to what extent, halogen bonding could be employed to influence conformation, binding or reactivity in the solution phase. This tutorial review summarizes and interprets solution-phase thermodynamic data for halogen bonding interactions obtained over the past six decades and highlights emerging applications in molecular recognition, medicinal chemistry and catalysis.

Level changes and human dietary exposure assessment of halogenated flame retardant levels in free-range chicken eggs: A case study of a former e-waste recycling site, South China.

PubMed

Huang, Chen-Chen; Zeng, Yan-Hong; Luo, Xiao-Jun; Tang, Bin; Liu, Yin-E; Ren, Zi-He; Mai, Bi-Xian

2018-09-01

To assess the impacts of e-waste regulations on environmental pollution, we built on a previous study from 2010 to investigate the levels and human dietary exposure of halogenated flame retardants (HFRs) in free-range chicken eggs from Baihe village in 2013 and 2016. The concentrations of PBDEs, PBBs, HBCDs, and DBDPE showed a significant decrease (p<0.05) from 2010 to 2013/2016, suggesting the efficacy of regulatory policies. The relative contribution of BDE209 were higher in 2013 and 2016 than in 2010, accounting for 67.8%, 61.4%, and 27.7%, respectively. The concentration ratios of PBB209:PBB153 were much lower in 2013 (1.51) and 2016 (1.32) than in 2010 (29.5). These observed different profiles likely due to the different environmental behaviors of HFRs (e.g. the different atmospheric migration abilities of PBDE congeners and degradation of PBB209). Our exposure estimates suggested high dietary intake of HFRs via home-produced eggs. As for PBDEs, considering the worst situation (highly polluted eggs were consumed), the margin of exposure (MOE) of BDE99 for both adults and children were 1.5 and 0.3 in 2013, and 1.1 and 0.2 in 2016, respectively, which were below 2.5. According to the CONTAM panel, an MOE larger than 2.5 indicates no health concern. Therefore, these MOE values represent a significant potential health concern due to the adverse impacts of PBDEs on human neurodevelopment and fertility. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization of anthropogenic impacts in a large urban center by examining the spatial distribution of halogenated flame retardants.

PubMed

Wei, Yan-Li; Bao, Lian-Jun; Wu, Chen-Chou; Zeng, Eddy Y

2016-08-01

Anthropogenic impacts have continuously intensified in mega urban centers with increasing urbanization and growing population. The spatial distribution pattern of such impacts can be assessed with soil halogenated flame retardants (HFRs) as HFRs are mostly derived from the production and use of various consumer products. In the present study, soil samples were collected from the Pearl River Delta (PRD), a large urbanized region in southern China, and its surrounding areas and analyzed for a group of HFRs, i.e., polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane, bis(hexachlorocyclopentadieno)cyclooctane (DP) and hexabromobenzene. The sum concentrations of HFRs and PBDEs were in the ranges of 0.66-6500 and 0.37-5700 (mean: 290 and 250) ng g(-1) dry weight, respectively, around the middle level of the global range. BDE-209 was the predominant compound likely due to the huge amounts of usage and its persistence. The concentrations of HFRs were greater in the land-use types of residency, industry and landfill than in agriculture, forestry and drinking water source, and were also greater in the central PRD than in its surrounding areas. The concentrations of HFRs were moderately significantly (r(2) = 0.32-0.57; p < 0.05) correlated with urbanization levels, population densities and gross domestic productions in fifteen administrative districts. The spatial distribution of DP isomers appeared to be stereoselective as indicated by the similarity in the spatial patterns for the ratio of anti-DP versus the sum of DP isomers (fanti-DP) and DP concentrations. Finally, the concentrations of HFRs sharply decreased with increasing distance from an e-waste recycling site, indicating that e-waste derived HFRs largely remained in local soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

Implementation of marine halogen chemistry into the Community Multiscale Air Quality (CMAQ) model

NASA Astrophysics Data System (ADS)

Gantt, B.; Sarwar, G.

2017-12-01

In two recent studies (Sarwar et al, 2015 and Gantt et al., 2017), the impact of marine halogen (bromine and iodine) chemistry on air quality has been evaluated using the Community Multiscale Air Quality (CMAQ) model. We found that marine halogen chemistry not only has the expected effect of reducing marine boundary layer ozone concentrations, but also reduces ozone in the free troposphere and inland from the coast. In Sarwar et al. (2015), the impact of the halogen chemistry without and with photochemical reactions of higher iodine oxides over the Northern Hemisphere was examined using the coarse horizontal grids of a hemispheric domain. Halogen chemistry without and with the photochemical reactions of higher iodine oxides reduces ozone over seawater by 15% and 48%, respectively. Using the results of the chemistry without the photochemical reactions of higher iodine oxides, we developed a simple first order ozone loss rate and implemented it into the public version of CMAQv52. In Gantt et al. (2017), the impact of the simple first order loss rate as well as the full halogen chemistry without photochemical reactions of higher iodine oxides over the continental United States was examined using finer horizontal grids of the regional domain and boundary conditions from the hemispheric domain with and without marine halogen chemistry. The boundary conditions obtained with the halogen chemistry as well as the simple halogen chemistry reduces ozone along the coast where CMAQ typically overpredicts the concentrations. Development of halogen chemistry in CMAQ has continued with the implementation of several heterogeneous reactions of bromine and iodine species, revised reactions of higher iodine oxides, and a refined marine halogen emissions inventory. Our latest version of halogen chemistry with photochemical reactions of higher iodine oxides reduces ozone by 23% over the seawater. This presentation will discuss the previous and ongoing implementation of revised halogen chemistry in CMAQ and its impacts on air quality.

Technology for radiation efficiency measurement of high-power halogen tungsten lamp used in calibration of high-energy laser energy meter.

PubMed

Wei, Ji Feng; Hu, Xiao Yang; Sun, Li Qun; Zhang, Kai; Chang, Yan

2015-03-20

The calibration method using a high-power halogen tungsten lamp as a calibration source has many advantages such as strong equivalence and high power, so it is very fit for the calibration of high-energy laser energy meters. However, high-power halogen tungsten lamps after power-off still reserve much residual energy and continually radiate energy, which is difficult to be measured. Two measuring systems were found to solve the problems. One system is composed of an integrating sphere and two optical spectrometers, which can accurately characterize the radiative spectra and power-time variation of the halogen tungsten lamp. This measuring system was then calibrated using a normal halogen tungsten lamp made of the same material as the high-power halogen tungsten lamp. In this way, the radiation efficiency of the halogen tungsten lamp after power-off can be quantitatively measured. In the other measuring system, a wide-spectrum power meter was installed far away from the halogen tungsten lamp; thus, the lamp can be regarded as a point light source. The radiation efficiency of residual energy from the halogen tungsten lamp was computed on the basis of geometrical relations. The results show that the halogen tungsten lamp's radiation efficiency was improved with power-on time but did not change under constant power-on time/energy. All the tested halogen tungsten lamps reached 89.3% of radiation efficiency at 50 s after power-on. After power-off, the residual energy in the halogen tungsten lamp gradually dropped to less than 10% of the initial radiation power, and the radiation efficiency changed with time. The final total radiation energy was decided by the halogen tungsten lamp's radiation efficiency, the radiation efficiency of residual energy, and the total power consumption. The measuring uncertainty of total radiation energy was 2.4% (here, the confidence factor is two).

Independent Evolution of Six Families of Halogenating Enzymes

PubMed Central

Xu, Gangming; Wang, Bin-Gui

2016-01-01

Halogenated natural products are widespread in the environment, and the halogen atoms are typically vital to their bioactivities. Thus far, six families of halogenating enzymes have been identified: cofactor-free haloperoxidases (HPO), vanadium-dependent haloperoxidases (V-HPO), heme iron-dependent haloperoxidases (HI-HPO), non-heme iron-dependent halogenases (NI-HG), flavin-dependent halogenases (F-HG), and S-adenosyl-L-methionine (SAM)-dependent halogenases (S-HG). However, these halogenating enzymes with similar biological functions but distinct structures might have evolved independently. Phylogenetic and structural analyses suggest that the HPO, V-HPO, HI-HPO, NI-HG, F-HG, and S-HG enzyme families may have evolutionary relationships to the α/β hydrolases, acid phosphatases, peroxidases, chemotaxis phosphatases, oxidoreductases, and SAM hydroxide adenosyltransferases, respectively. These halogenating enzymes have established sequence homology, structural conservation, and mechanistic features within each family. Understanding the distinct evolutionary history of these halogenating enzymes will provide further insights into the study of their catalytic mechanisms and halogenation specificity. PMID:27153321

APPLICATIONS OF SURFACE ANALYSIS IN THE ENVIRONMENTAL SCIENCES: DEHALOGENATION OF CHLOROCARBONS WITH ZERO-VALENT IRON AND IRON-CONTAINING MINERAL SURFACES. (R828164)

EPA Science Inventory

Halogenated organic compounds are common pollutants in groundwater. Consequently, there is widespread interest in understanding the reactions of these compounds in the environment and developing remediation strategies. One area of ongoing research involves the reductive dechlo...

ENVIROMETAL TECHNOLOGIES, INC. - METAL-ENHANCED DECHLORINATION OF VOLATILE ORGANIC COMPOUNDS USING AN ABOVE-GROUND REACTOR, INNOVATIVE TECHNOLOGY EVALUATION REPORT

EPA Science Inventory

EnviroMetal Technology's metal-enhanced dechlorination technology employs an electrochemical process that involves oxidation of iron and reductive dehalogenation of halogenated VOCs in aqueous media. The process can be operated as an above ground reactor or can alternatively perf...

Metal complexes of substituted Gable porphyrins as oxidation catalysts

DOEpatents

Lyons, J.E.; Ellis, P.E. Jr.; Wagner, R.W.

1996-01-02

Transition metal complexes of Gable porphyrins are disclosed having two porphyrin rings connected through a linking group, and having on the porphyrin rings electron-withdrawing groups, such as halogen, nitro or cyano. These complexes are useful as catalysts for the oxidation of organic compounds, e.g. alkanes.

GEOCHEMICAL AND MICROBIAL REACTIONS AFFECTING THE LONG-TERM PERFORMANCE OF IN SITU 'IRON BARRIERS'

EPA Science Inventory

The in situ application of granular iron (Fe0) has become popular for the destruction of halogenated organic compounds for the immobilization of specific metals in groundwater. However, a knowledge gap exists concerning the long-term performance of the Fe0-barriers. The corrosi...

Halogenation of microcapsule walls

NASA Technical Reports Server (NTRS)

Davis, T. R.; Schaab, C. K.; Scott, J. C.

1972-01-01

Procedure for halogenation of confining walls of both gelatin and gelatin-phenolic resin capsules is similar to that used for microencapsulation. Ten percent halogen content renders capsule wall nonburning; any higher content enhances flame-retardant properties of selected internal phase material. Halogenation decreases permeability of wall material to encapsulated materials.

Halogens are key cofactors in building of collagen IV scaffolds outside the cell.

PubMed

Brown, Kyle L; Hudson, Billy G; Voziyan, Paul A

2018-05-01

The purpose of this review is to highlight recent advances in understanding the molecular assembly of basement membranes, as exemplified by the glomerular basement membrane (GBM) of the kidney filtration apparatus. In particular, an essential role of halogens in the basement membrane formation has been discovered. Extracellular chloride triggers a molecular switch within non collagenous domains of collagen IV that induces protomer oligomerization and scaffold assembly outside the cell. Moreover, bromide is an essential cofactor in enzymatic cross-linking that reinforces the stability of scaffolds. Halogenation and halogen-induced oxidation of the collagen IV scaffold in disease states damage scaffold function. Halogens play an essential role in the formation of collagen IV scaffolds of basement membranes. Pathogenic damage of these scaffolds by halogenation and halogen-induced oxidation is a potential target for therapeutic interventions.

The Potential Feasibility of Chlorinic Photosynthesis on Exoplanets

NASA Astrophysics Data System (ADS)

Haas, Johnson R.

2010-11-01

The modern search for life-bearing exoplanets emphasizes the potential detection of O2 and O3 absorption spectra in exoplanetary atmospheres as ideal signatures of biology. However, oxygenic photosynthesis may not arise ubiquitously in exoplanetary biospheres. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This paper defines chlorinic photosynthesis (CPS) as biologically mediated photolytic oxidation of aqueous Cl- to form halocarbon or dihalogen products, coupled with CO2 assimilation. This hypothetical metabolism appears to be feasible energetically, physically, and geochemically, and could potentially develop under conditions that approximate the terrestrial Archean. It is hypothesized that an exoplanetary biosphere in which chlorinic photosynthesis dominates primary production would tend to evolve a strongly oxidizing, halogen-enriched atmosphere over geologic time. It is recommended that astronomical observations of exoplanetary outgoing thermal emission spectra consider signs of halogenated chemical species as likely indicators of the presence of a chlorinic biosphere. Planets that favor the evolution of CPS would probably receive equivalent or greater surface UV flux than is produced by the Sun, which would promote stronger abiotic UV photolysis of aqueous halides than occurred during Earth's Archean era and impose stronger evolutionary selection pressures on endemic life to accommodate and utilize halogenated compounds. Ocean-bearing planets of stars with metallicities equivalent to, or greater than, the Sun should especially favor the evolution of chlorinic biospheres because of the higher relative seawater abundances of Cl, Br, and I such planets would tend to host. Directed searches for chlorinic biospheres should probably focus on G0-G2, F, and A spectral class stars that have bulk metallicities of +0.0 Dex or greater.

The Potential Feasibility of Chlorinic Photosynthesis on Extrasolar Planets

NASA Astrophysics Data System (ADS)

Haas, Johnson

2009-09-01

It is highly likely that the first convincing evidence of extrasolar life will arrive in the form of atmospheric absorption spectra. The modern search for life-bearing extrasolar planets emphasizes the potential detection of O2 and O3 absorption spectra in exoplanetary atmospheres as archetypal signatures of biology. However, oxygenic photosynthesis apparently failed to evolve independently more than once on Earth, and is thus unlikely to be reliably ubiquitous throughout the universe. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This study examines the potential feasibility of one such exotic metabolism: chlorinic photosynthesis (CPS), defined as biologically-mediated halogenation of aqueous chloride to HClO, Cl2 or partially-oxidized intermediates (e.g. haloalkanes, haloacids, haloaromatics), coupled with photosynthetic CO2 fixation. This metabolic couple is feasible thermodynamically and appears to be geochemically plausible under approximately terrestrial conditions. This study hypothesizes that planetary biospheres dominated by CPS would develop atmospheres enriched with dihalogens and other halogenated compounds, evolve a highly oxidizing surface geochemical environment, and foster biological selection pressures favoring halogen resistance and eventual metazoan heterotrophy based on dihalogen and halocarbon respiration. Planets favoring the evolution of CPS would probably receive equivalent or greater surface UV flux than Earth did in the Paleoarchean (promoting abiotic photo-oxidation of aqueous halides, and establishing a strong biological selective pressure toward their accommodation), and would orbit stars having equivalent or greater bulk metallicities (promoting greater planetary halide abundances) relative to the Sun. Directed searches for such worlds should probably focus on A, F and G0 spectral class stars having bulk metallicities of +0.0 Dex or greater.

The potential feasibility of chlorinic photosynthesis on exoplanets.

PubMed

Haas, Johnson R

2010-11-01

The modern search for life-bearing exoplanets emphasizes the potential detection of O(2) and O(3) absorption spectra in exoplanetary atmospheres as ideal signatures of biology. However, oxygenic photosynthesis may not arise ubiquitously in exoplanetary biospheres. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This paper defines chlorinic photosynthesis (CPS) as biologically mediated photolytic oxidation of aqueous Cl(-) to form halocarbon or dihalogen products, coupled with CO(2) assimilation. This hypothetical metabolism appears to be feasible energetically, physically, and geochemically, and could potentially develop under conditions that approximate the terrestrial Archean. It is hypothesized that an exoplanetary biosphere in which chlorinic photosynthesis dominates primary production would tend to evolve a strongly oxidizing, halogen-enriched atmosphere over geologic time. It is recommended that astronomical observations of exoplanetary outgoing thermal emission spectra consider signs of halogenated chemical species as likely indicators of the presence of a chlorinic biosphere. Planets that favor the evolution of CPS would probably receive equivalent or greater surface UV flux than is produced by the Sun, which would promote stronger abiotic UV photolysis of aqueous halides than occurred during Earth's Archean era and impose stronger evolutionary selection pressures on endemic life to accommodate and utilize halogenated compounds. Ocean-bearing planets of stars with metallicities equivalent to, or greater than, the Sun should especially favor the evolution of chlorinic biospheres because of the higher relative seawater abundances of Cl, Br, and I such planets would tend to host. Directed searches for chlorinic biospheres should probably focus on G0-G2, F, and A spectral class stars that have bulk metallicities of +0.0 Dex or greater.

40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting under...

40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting under...

Halogen bonding based recognition processes: a world parallel to hydrogen bonding.

PubMed

Metrangolo, Pierangelo; Neukirch, Hannes; Pilati, Tullio; Resnati, Giuseppe

2005-05-01

Halogen bonding is the noncovalent interaction between halogen atoms (Lewis acids) and neutral or anionic Lewis bases. The main features of the interaction are given, and the close similarity with the hydrogen bonding will become apparent. Some heuristic principles are presented to develop a rational crystal engineering based on halogen bonding. The focus is on halogen-bonded supramolecular architectures given by halocarbons. The potential of the interaction is shown by useful applications in the field of synthetic chemistry, material science, and bioorganic chemistry.

Impact of Convection and Long Range Transport on Short-Lived Trace Gases in the UT/LS

NASA Astrophysics Data System (ADS)

Atlas, E. L.; Schauffler, S.; Navarro, M. A.; Lueb, R.; Hendershot, R.; Ueyama, R.

2017-12-01

Chemical composition of the air in the upper troposphere/lower stratosphere is controlled by a balance of transport, photochemistry, and physical processes, such as interactions with clouds, ice, and aerosol. The chemistry of the air masses that reach the upper troposphere can potentially have profound impacts on the chemistry in the near tropopause region. For example, the transport of reactive organic halogens and their transformation to inorganic halogen species, e.g., Br, BrO, etc., can have a significant impact on ozone budgets in this region and even deeper the stratosphere. Trace gas measurements in the region near the tropopause can also indicate potential sources of surface emissions that are transported to high altitudes. Measurement of trace gases, including such compounds as non-methane hydrocarbons, hydrochlorofluorocarbons, halogenated solvents, methyl halides, etc., can be used to characterize source emissions from industrial, urban, biomass burning, or marine origins. Recent airborne research campaigns have been conducted to better characterize the chemical composition and variations in the UT/LS region. This presentation will discuss these measurements, with a special emphasis on the role of convection and transport in modifying the chemical composition of the UT/LS.

Halogen Radicals Promote the Photodegradation of Microcystins in Estuarine Systems.

PubMed

Parker, Kimberly M; Reichwaldt, Elke S; Ghadouani, Anas; Mitch, William A

2016-08-16

The transport of microcystin, a hepatotoxin produced by cyanobacteria (e.g., Microcystis aeruginosa), to estuaries can adversely affect estuarine and coastal ecosystems. We evaluated whether halogen radicals (i.e., reactive halogen species (RHS)) could significantly contribute to microcystin photodegradation during transport within estuaries. Experiments in synthetic and natural water samples demonstrated that the presence of seawater halides increased quantum yields for microcystin indirect photodegradation by factors of 3-6. Additional experiments indicated that photoproduced RHS were responsible for this effect. Despite the fact that dissolved organic matter (DOM) concentrations decreased in more saline waters, the calculated photochemical half-life of microcystin decreased 6-fold with increasing salinity along a freshwater-estuarine transect due to the halide-associated increase in quantum yield. Modeling of microcystin photodegradation along this transect indicated that the time scale for RHS-mediated microcystin photodegradation is comparable to the time scale of transport. Microcystin concentrations decline by ∼98% along the transect when considering photodegradation by RHS, but only by ∼54% if this pathway were ignored. These results suggest the importance of considering RHS-mediated photodegradation in future models of microcystin fate in freshwater-estuarine systems.

Pyrrolo isoquinolines

DOEpatents

Goodman, Mark M.; Shi, Bing Z.

2000-01-01

Compounds of the formula: ##STR1## wherein X, Y, and R, independently of one another, is each a H; halogen, wherein said halogen is selected from the group consisting of .sup.123 I, .sup.124 I, .sup.125 I, .sup.131 I, .sup.75 Br, .sup.76 Br, .sup.77 Br, .sup.82 Br, .sup.18 F, or .sup.210 At; small alkyl, small alkenyl, or small alkynyl, any of which contains from one to about six carbon atoms and optionally having a carbon atom replaced by an O or S; or halogen substituted-small alkyl, halogen substituted-small alkenyl, or halogen substituted-small alkynyl wherein said compound contains at least one radioacitve halogen. The compounds bind to the serotonin transporter. Depending upon the choice of halogen substituent, the compounds are useful for PET or SPECT imaging, diagnosis and treatment of psychiatric disorders such as depression, anxiety, obsessive-compulsive disorder, and other conditions associated with defects of serotonin transporter function.

40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Halogenated-N-(2-propenyl)-N... New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl... identified generically as halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide (P-83-1085) is subject...

40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated-N-(2-propenyl)-N... New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl... identified generically as halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide (P-83-1085) is subject...

Do Halogen–Hydrogen Bond Donor Interactions Dominate the Favorable Contribution of Halogens to Ligand–Protein Binding?

PubMed Central

2017-01-01

Halogens are present in a significant number of drugs, contributing favorably to ligand–protein binding. Currently, the contribution of halogens, most notably chlorine and bromine, is largely attributed to halogen bonds involving favorable interactions with hydrogen bond acceptors. However, we show that halogens acting as hydrogen bond acceptors potentially make a more favorable contribution to ligand binding than halogen bonds based on quantum mechanical calculations. In addition, bioinformatics analysis of ligand–protein crystal structures shows the presence of significant numbers of such interactions. It is shown that interactions between halogens and hydrogen bond donors (HBDs) are dominated by perpendicular C–X···HBD orientations. Notably, the orientation dependence of the halogen–HBD (X–HBD) interactions is minimal over greater than 100° with favorable interaction energies ranging from −2 to −14 kcal/mol. This contrasts halogen bonds in that X–HBD interactions are substantially more favorable, being comparable to canonical hydrogen bonds, with a smaller orientation dependence, such that they make significant, favorable contributions to ligand–protein binding and, therefore, should be actively considered during rational ligand design. PMID:28657759

Nitrogen, Aerosol Composition, and Halogens on a Tall Tower (NACHTT): Overview of a wintertime air chemistry field study in the front range urban corridor of Colorado

NASA Astrophysics Data System (ADS)

Brown, Steven S.; Thornton, Joel A.; Keene, William C.; Pszenny, Alexander A. P.; Sive, Barkley C.; Dubé, William P.; Wagner, Nicholas L.; Young, Cora J.; Riedel, Theran P.; Roberts, James M.; VandenBoer, Trevor C.; Bahreini, Roya; Öztürk, Fatma; Middlebrook, Ann M.; Kim, Saewung; Hübler, Gerhard; Wolfe, Daniel E.

2013-07-01

The Nitrogen, Aerosol Composition, and Halogens on a Tall Tower (NACHTT) field experiment took place during late winter, 2011, at a site 33 km north of Denver, Colorado. The study included fixed-height measurements of aerosols, soluble trace gases, and volatile organic compounds near surface level, as well as vertically resolved measurements of nitrogen oxides, aerosol composition, soluble gas-phase acids, and halogen species from 3 to 270 m above ground level. There were 1928 individual profiles during the three-week campaign to characterize trace gas and aerosol distributions in the lower levels of the boundary layer. Nitrate and ammonium dominated the ionic composition of aerosols and originated primarily from local or regional sources. Sulfate and organic matter were also significant and were associated primarily with longer-range transport to the region. Aerosol chloride was associated primarily with supermicron size fractions and was always present in excess of gas-phase chlorine compounds. The nighttime radical reservoirs, nitryl chloride, ClNO2, and nitrous acid, HONO, were both consistently present in nighttime urban air. Nitryl chloride was especially pronounced in plumes from large point sources sampled aloft at night. Nitrous acid was typically most concentrated near the ground surface and was the dominant contributor (80%) to diurnally averaged primary OH radical production in near-surface air. Large observed mixing ratios of light alkanes, both in near-surface air and aloft, were attributable to local emissions from oil and gas activities.

Hydrogen bond and halogen bond inside the carbon nanotube

NASA Astrophysics Data System (ADS)

Wang, Weizhou; Wang, Donglai; Zhang, Yu; Ji, Baoming; Tian, Anmin

2011-02-01

The hydrogen bond and halogen bond inside the open-ended single-walled carbon nanotubes have been investigated theoretically employing the newly developed density functional M06 with the suitable basis set and the natural bond orbital analysis. Comparing with the hydrogen or halogen bond in the gas phase, we find that the strength of the hydrogen or halogen bond inside the carbon nanotube will become weaker if there is a larger intramolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom donor to the antibonding orbital of the X-H or X-Hal bond involved in the formation of the hydrogen or halogen bond and will become stronger if there is a larger intermolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom acceptor to the antibonding orbital of the X-H or X-Hal bond. According to the analysis of the molecular electrostatic potential of the carbon nanotube, the driving force for the electron-density transfer is found to be the negative electric field formed in the carbon nanotube inner phase. Our results also show that the X-H bond involved in the formation of the hydrogen bond and the X-Hal bond involved in the formation of the halogen bond are all elongated when encapsulating the hydrogen bond and halogen bond within the carbon nanotube, so the carbon nanotube confinement may change the blue-shifting hydrogen bond and the blue-shifting halogen bond into the red-shifting hydrogen bond and the red-shifting halogen bond. The possibility to replace the all electron nanotube-confined calculation by the simple polarizable continuum model is also evaluated.

On the ultrafast charge migration and subsequent charge directed reactivity in Cl⋯N halogen-bonded clusters following vertical ionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chandra, Sankhabrata; Bhattacharya, Atanu, E-mail: atanub@ipc.iisc.ernet.in; Periyasamy, Ganga

2015-06-28

In this article, we have presented ultrafast charge transfer dynamics through halogen bonds following vertical ionization of representative halogen bonded clusters. Subsequent hole directed reactivity of the radical cations of halogen bonded clusters is also discussed. Furthermore, we have examined effect of the halogen bond strength on the electron-electron correlation- and relaxation-driven charge migration in halogen bonded complexes. For this study, we have selected A-Cl (A represents F, OH, CN, NH{sub 2}, CF{sub 3}, and COOH substituents) molecules paired with NH{sub 3} (referred as ACl:NH{sub 3} complex): these complexes exhibit halogen bonds. To the best of our knowledge, this ismore » the first report on purely electron correlation- and relaxation-driven ultrafast (attosecond) charge migration dynamics through halogen bonds. Both density functional theory and complete active space self-consistent field theory with 6-31 + G(d, p) basis set are employed for this work. Upon vertical ionization of NCCl⋯NH{sub 3} complex, the hole is predicted to migrate from the NH{sub 3}-end to the ClCN-end of the NCCl⋯NH{sub 3} complex in approximately 0.5 fs on the D{sub 0} cationic surface. This hole migration leads to structural rearrangement of the halogen bonded complex, yielding hydrogen bonding interaction stronger than the halogen bonding interaction on the same cationic surface. Other halogen bonded complexes, such as H{sub 2}NCl:NH{sub 3}, F{sub 3}CCl:NH{sub 3}, and HOOCCl:NH{sub 3}, exhibit similar charge migration following vertical ionization. On the contrary, FCl:NH{sub 3} and HOCl:NH{sub 3} complexes do not exhibit any charge migration following vertical ionization to the D{sub 0} cation state, pointing to interesting halogen bond strength-dependent charge migration.« less

Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer–chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS)

USGS Publications Warehouse

Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B.; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A.; Schimmelmann, Arndt

2017-01-01

Conclusions: The optimized EA-Cr/HTC reactor design can be implemented in existing analytical equipment using commercially available material and is universally applicable for both heteroelement-bearing and heteroelement-free organic-compound classes. The sensitivity and simplicity of the on-line EA-Cr/HTC-IRMS technique provide a much needed tool for routine hydrogen-isotope source tracing of organic contaminants in the environment. Copyright © 2016 John Wiley & Sons, Ltd.

Metallocene catalyst containing bulky organic group

DOEpatents

Marks, T.J.; Ja, L.; Yang, X.

1996-03-26

An ionic metallocene catalyst for olefin polymerization which comprises: (1) a cyclopentadienyl-type ligand, a Group IVB transition metal, and alkyl, aryl, or hydride substituents, as a cation, and (2) a weakly coordinating anion comprising boron substituted with halogenated, such as tetrafluoro-aryl substituents preferably containing silylalkyl substitution, such as para-silyl t-butyldimethyl.

Investigating a Chemoselective Grignard Reaction in an Undergraduate Discovery Lab to Predict Reactivity and Final Products

ERIC Educational Resources Information Center

Maher, Michael J.; Hayes, Colin O.; Vaccaro, Francesca A.; Flynn, Cailyn B.; Thedford, R. Paxton; Stephenson, Clifton J.

2016-01-01

A discovery-based Grignard experiment that emphasizes several important concepts in organic chemistry is reported. The Grignard reagent from 1- bromo-4-chlorobenzene was prepared and reacted with dimethylformamide (DMF) to synthesize 4-chlorobenzaldehyde. Students were tasked with predicting halogen reactivity in the formation of the Grignard…

Effect of 2,4-Dichlorophenoxyacetic Acid (2,4-D) on PCDD/F Emissions from Open Burning of Biomass

EPA Science Inventory

Use of pesticides prior to agricultural burning and overspray onto forests and grasslands prior to fires has been cited as a cause of halogenated organic compound emissions from biomass combustion. Some pesticides such as 2,4-dichlorophenoxyacetic acid (2,4-D) are used in conside...

Metallocene catalyst containing bulky organic group

DOEpatents

Marks, Tobin J.; Ja, Li; Yang, Xinmin

1996-03-26

An ionic metallocene catalyst for olefin polymerization which comprises: (1) a cyclopentadienyl-type ligand, a Group IVB transition metal, and alkyl, aryl, or hydride substituents, as a cation, and (2) a weakly coordinating anion comprising boron substituted with halogenated, such as tetra fluoro, aryl substituents preferably containing silylalkyl substitution, such as para-silyl t-butyldimethyl.

Electron transport chains in organohalide-respiring bacteria and bioremediation implications.

PubMed

Wang, Shanquan; Qiu, Lan; Liu, Xiaowei; Xu, Guofang; Siegert, Michael; Lu, Qihong; Juneau, Philippe; Yu, Ling; Liang, Dawei; He, Zhili; Qiu, Rongliang

In situ remediation employing organohalide-respiring bacteria represents a promising solution for cleanup of persistent organohalide pollutants. The organohalide-respiring bacteria conserve energy by utilizing H 2 or organic compounds as electron donors and organohalides as electron acceptors. Reductive dehalogenase (RDase), a terminal reductase of the electron transport chain in organohalide-respiring bacteria, is the key enzyme that catalyzes halogen removal. Accumulating experimental evidence thus far suggests that there are distinct models for respiratory electron transfer in organohalide-respirers of different lineages, e.g., Dehalococcoides, Dehalobacter, Desulfitobacterium and Sulfurospirillum. In this review, to connect the knowledge in organohalide-respiratory electron transport chains to bioremediation applications, we first comprehensively review molecular components and their organization, together with energetics of the organohalide-respiratory electron transport chains, as well as recent elucidation of intramolecular electron shuttling and halogen elimination mechanisms of RDases. We then highlight the implications of organohalide-respiratory electron transport chains in stimulated bioremediation. In addition, major challenges and further developments toward understanding the organohalide-respiratory electron transport chains and their bioremediation applications are identified and discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

Strategies for Controlling and Removing Trace Organic Compounds Found in Potable Water Supplies at Fixed Army Installations

DTIC Science & Technology

1985-08-01

have been practiced at Army and municipal water treatment plants. Oxidation/ Disinfection - T -HM Control Although THMs are the only halogenated organics...Table 9 USEPA-Identlf led Methods to Achieve Compliance With 0.1 mg/L, MCL for THMs * Using chloramines as an alternative or supplemental disinfectant ...chlorine Is applied for final disinfection . A residual disinfection coin be added to the distribution systems using chloramines or chlorine dioxide

Concentration-dependent multiple chirality transition in halogen-bond-driven 2D self-assembly process

NASA Astrophysics Data System (ADS)

Miao, Xinrui; Li, Jinxing; Zha, Bao; Miao, Kai; Dong, Meiqiu; Wu, Juntian; Deng, Wenli

2018-03-01

The concentration-dependent self-assembly of iodine substituted thienophenanthrene derivative (5,10-DITD) is investigated at the 1-octanic acid/graphite interface using scanning tunneling microscopy. Three kinds of chiral arrangement and transition of 2D molecular assembly mainly driven by halogen bonding is clearly revealed. At high concentration the molecules self-assembled into a honeycomb-like chiral network. Except for the interchain van der Waals forces, this pattern is stabilized by intermolecular continuous Cdbnd O⋯I⋯S halogen bonds in each zigzag line. At moderate concentration, a chiral kite-like nanoarchitecture are observed, in which the Cdbnd O⋯I⋯S and I⋯Odbnd C halogen bonds, along with the molecule-solvent Cdbnd O⋯I⋯H halogen bonds are the dominated forces to determine the structural formation. At low concentration, the molecules form a chiral cyclic network resulting from the solvent coadsorption mainly by molecule-molecule Cdbnd O⋯I⋯S halogen bonds and molecule-solvent Cdbnd O⋯I⋯H halogen bonds. The density of molecular packing becomes lower with the decreasing of the solution concentration. The solution-concentration dependent self-assembly of thienophenanthrene derivative with iodine and ester chain moieties reveals that the type of intermolecular halogen bond and the number of the co-adsorbing 1-octanic acids by molecule-solvent Cdbnd O⋯I⋯H halogen bonds determine the formation and transformation of chirality. This research emphasizes the role of different types of halogen (I) bonds in the controllable supramolecular structures and provides an approach for the fabrication of chirality.

Halogen bond: a long overlooked interaction.

PubMed

Cavallo, Gabriella; Metrangolo, Pierangelo; Pilati, Tullio; Resnati, Giuseppe; Terraneo, Giancarlo

2015-01-01

Because of their high electronegativity, halogen atoms are typically considered, in most of their derivatives, as sites of high electron density and it is commonly accepted that they can form attractive interactions by functioning as the electron donor site (nucleophilic site). This is the case when they work as hydrogen bond acceptor sites. However, the electron density in covalently bound halogens is anisotropically distributed. There is a region of higher electron density, accounting for the ability of halogens to function as electron donor sites in attractive interactions, and a region of lower electron density where the electrostatic potential is frequently positive (mainly in the heavier halogens). This latter region is responsible for the ability of halogen atoms to function as the electron-acceptor site (electrophilic site) in attractive interactions formed with a variety of lone pair-possessing atoms, anions, and π-systems. This ability is quite general and is shown by a wide diversity of halogenated compounds (e.g., organohalogen derivatives and dihalogens). According to the definition proposed by the International Union of Pure and Applied Chemistry, any attractive interactions wherein the halogen atom is the electrophile is named halogen bond (XB). In this chapter, it is discussed how the practice and the concept of XB developed and a brief history of the interaction is presented. Papers (either from the primary or secondary literature) which have reported major experimental findings in the field or which have given important theoretical contributions for the development of the concept are recollected in order to trace how a unifying and comprehensive categorization emerged encompassing all interactions wherein halogen atoms function as the electrophilic site.

The unique role of halogen substituents in the design of modern agrochemicals.

PubMed

Jeschke, Peter

2010-01-01

The past 30 years have witnessed a period of significant expansion in the use of halogenated compounds in the field of agrochemical research and development. The introduction of halogens into active ingredients has become an important concept in the quest for a modern agrochemical with optimal efficacy, environmental safety, user friendliness and economic viability. Outstanding progress has been made, especially in synthetic methods for particular halogen-substituted key intermediates that were previously prohibitively expensive. Interestingly, there has been a rise in the number of commercial products containing 'mixed' halogens, e.g. one or more fluorine, chlorine, bromine or iodine atoms in addition to one or more further halogen atoms. Extrapolation of the current trend indicates that a definite growth is to be expected in fluorine-substituted agrochemicals throughout the twenty-first century. A number of these recently developed agrochemical candidates containing halogen substituents represent novel classes of chemical compounds with new modes of action. However, the complex structure-activity relationships associated with biologically active molecules mean that the introduction of halogens can lead to either an increase or a decrease in the efficacy of a compound, depending on its changed mode of action, physicochemical properties, target interaction or metabolic susceptibility and transformation. In spite of modern design concepts, it is still difficult to predict the sites in a molecule at which halogen substitution will result in optimal desired effects. This review describes comprehensively the successful utilisation of halogens and their unique role in the design of modern agrochemicals, exemplified by various commercial products from Bayer CropScience coming from different agrochemical areas.

Engineered biofiltration for the removal of disinfection by-product precursors and genotoxicity.

PubMed

McKie, Michael J; Taylor-Edmonds, Liz; Andrews, Susan A; Andrews, Robert C

2015-09-15

Disinfection by-products (DBPs) are formed when naturally occurring organic matter reacts with chlorine used in drinking water treatment, and DBPs formed in chlorinated drinking water samples have been shown to cause a genotoxic response. The objective of the current study was to further understand the principles of biofiltration and the resulting impacts on the formation of DBPs and genotoxicity. Pilot-scale systems were utilized to assess the performance of engineered biofilters enhanced with hydrogen peroxide, in-line coagulants, and nutrients when compared to passively operated biofilters and conventional treatment (coagulation, flocculation, sedimentation, non-biological filtration). Organic fractionation was completed using liquid chromatography-organic carbon detection (LC-OCD). Water samples were chlorinated after collection and examined for the removal of trihalomethane (THM), haloacetic acid (HAA), and adsorbable organic halide (AOX) precursors. Additionally, the formation potential of two halogenated furanones, 3-chloro-4(dichloromethyl)-2(5H)-furanone (MX) and mucochloric acid (MCA), and genotoxicity was determined. Biofiltration was shown to preferentially remove more DBP precursors than dissolved organic carbon (DOC). Formation potential of the unregulated DBPs, including MX and MCA, and genotoxic response was shown to be correlated to THM formation. These results infer that monitoring for THMs and HAAs provide insight to the formation of more mutagenic DBPs such as halogenated furanones, and that biofiltration may preferentially remove precursors to DBPs at a rate exceeding the removal of DOC. Copyright © 2015 Elsevier Ltd. All rights reserved.

High temperature abatement of acid gases from waste incineration. Part I: experimental tests in full scale plants.

PubMed

Biganzoli, Laura; Racanella, Gaia; Rigamonti, Lucia; Marras, Roberto; Grosso, Mario

2015-02-01

In recent years, several waste-to-energy plants in Italy have experienced an increase of the concentration of acid gases (HCl, SO2 and HF) in the raw gas. This is likely an indirect effect of the progressive decrease of the amount of treated municipal waste, which is partially replaced by commercial waste. The latter is characterised by a higher variability of its chemical composition because of the different origins, with possible increase of the load of halogen elements such as chlorine (Cl) and fluorine (F), as well as of sulphur (S). A new dolomitic sorbent was then tested in four waste-to-energy plants during standard operation as a pre-cleaning stage, to be directly injected at high temperature in the combustion chamber. For a sorbent injection of about 6 kg per tonne of waste, the decrease of acid gases concentration downstream the boiler was in the range of 7-37% (mean 23%) for HCl, 34-95% (mean 71%) for SO2 and 39-80% (mean 63%) for HF. This pre-abatement of acid gases allowed to decrease the feeding rate of the traditional low temperature sorbent (sodium bicarbonate in all four plants) by about 30%. Furthermore, it was observed by the plant operators that the sorbent helps to keep the boiler surfaces cleaner, with a possible reduction of the fouling phenomena and a consequent increase of the specific energy production. A preliminary quantitative estimate was carried out in one of the four plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Boiling points of halogenated ethanes: an explanatory model implicating weak intermolecular hydrogen-halogen bonding.

PubMed

Beauchamp, Guy

2008-10-23

This study explores via structural clues the influence of weak intermolecular hydrogen-halogen bonds on the boiling point of halogenated ethanes. The plot of boiling points of 86 halogenated ethanes versus the molar refraction (linked to polarizability) reveals a series of straight lines, each corresponding to one of nine possible arrangements of hydrogen and halogen atoms on the two-carbon skeleton. A multiple linear regression model of the boiling points could be designed based on molar refraction and subgroup structure as independent variables (R(2) = 0.995, standard error of boiling point 4.2 degrees C). The model is discussed in view of the fact that molar refraction can account for approximately 83.0% of the observed variation in boiling point, while 16.5% could be ascribed to weak C-X...H-C intermolecular interactions. The difference in the observed boiling point of molecules having similar molar refraction values but differing in hydrogen-halogen intermolecular bonds can reach as much as 90 degrees C.

Halogen-free boron based electrolyte solution for rechargeable magnesium batteries

NASA Astrophysics Data System (ADS)

Zhu, Jinjie; Guo, Yongsheng; Yang, Jun; Nuli, Yanna; Zhang, Fan; Wang, Jiulin; Hirano, Shin-ichi

2014-02-01

All halogen containing electrolytes for Mg battery are apt to corrode conventional metal current collectors. In this paper, a new type of halogen-free boron based electrolyte (Mg[Mes3BPh]2/THF) is designed and prepared. Electrochemical tests show that this electrolyte system possesses high ion conductivity (1.5 × 10-3 S cm-1) and good Mg deposition-dissolution reversibility. More importantly, the same electrochemical window (2.6 V vs. Mg RE) of the electrolyte on Pt and stainless steel electrodes indicates that halogen-free electrolyte indeed lessens the corrosion to conventional metal current collectors. The surface morphologies of stainless steel, aluminum and copper are further observed after their anodic potentiostatic polarization in 0.25 mol L-1 Mg[Mes3BPh]2/THF electrolyte solution for 2 days. A comparison with halogen containing electrolytes proves that the presence of halogen in electrolyte is the reason for corrosion. This work provides a stepping stone for developing new halogen-free electrolyte systems for rechargeable Mg batteries.

Changes in dissolved organic matter during the treatment processes of a drinking water plant in Sweden and formation of previously unknown disinfection byproducts.

PubMed

Gonsior, Michael; Schmitt-Kopplin, Philippe; Stavklint, Helena; Richardson, Susan D; Hertkorn, Norbert; Bastviken, David

2014-11-04

The changes in dissolved organic matter (DOM) throughout the treatment processes in a drinking water treatment plant in Sweden and the formation of disinfection byproducts (DBPs) were evaluated by using ultra-high-resolution mass spectrometry (resolution of ∼500,000 at m/z 400) and nuclear magnetic resonance (NMR). Mass spectrometric results revealed that flocculation induced substantial changes in the DOM and caused quantitative removal of DOM constituents that usually are associated with DBP formation. While half of the chromophoric DOM (CDOM) was removed by flocculation, ∼4-5 mg L(-1) total organic carbon remained in the finished water. A conservative approach revealed the formation of ∼800 mass spectrometry ions with unambiguous molecular formula assignments that contained at least one halogen atom. These molecules likely represented new DBPs, which could not be prevented by the flocculation process. The most abundant m/z peaks, associated with formed DBPs, could be assigned to C5HO3Cl3, C5HO3Cl2Br, and C5HO3ClBr2 using isotope simulation patterns. Other halogen-containing formulas suggested the presence of halogenated polyphenolic and aromatic acid-type structures, which was supported by possible structures that matched the lower molecular mass range (maximum of 10 carbon atoms) of these DBPs. 1H NMR before and after disinfection revealed an ∼2% change in the overall 1H NMR signals supporting a significant change in the DOM caused by disinfection. This study underlines the fact that a large and increasing number of people are exposed to a very diverse pool of organohalogens through water, by both drinking and uptake through the skin upon contact. Nontarget analytical approaches are indispensable for revealing the magnitude of this exposure and to test alternative ways to reduce it.

Deriving an atmospheric budget of total organic bromine using airborne in-situ measurements from the Western Pacific during SHIVA

NASA Astrophysics Data System (ADS)

Sala, S.; Bönisch, H.; Keber, T.; Oram, D. E.; Mills, G.; Engel, A.

2014-02-01

During the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project an extensive dataset of all halogen species relevant for the atmospheric budget of total organic bromine has been collected in the West Pacific region using the FALCON aircraft operated by the German Aerospace agency DLR (Deutsches Zentrum für Luft- und Raumfahrt) covering a vertical range from the planetary boundary layer up to the ceiling altitude of the aircraft of 13 km. In total, more than 700 measurements were performed with the newly developed fully-automated in-situ instrument GHOST-MS (Gas cHromatograph for the Observation of Tracers - coupled with a Mass Spectrometer) by the Goethe University of Frankfurt (GUF) and with the onboard whole-air sampler WASP with subsequent ground based state-of-the-art GC/MS analysis by the University of East Anglia (UEA). Both instruments yield good agreement for all major (CHBr3 and CH2Br2) and minor (CHBrCl, CHBrCl2 and CHBr2Cl) VSLS (very short-lived substances), at least at the level of their 2 σ measurement uncertainties. In contrast to the suggestion that the Western Pacific could be a major source region for VSLS (Pyle et al., 2011), we found only slightly enhanced mixing ratios of brominated halogen source gases relative to the levels reported in Montzka et al. (2011) for other tropical regions. A budget for total organic bromine, including all four halons,CH3Br and the VSLS, is derived for the upper troposphere, the input region for the TTL and thus also for the stratosphere, compiled from the SHIVA dataset. With exception of the two minor VSLS CHBrCl2 and CHBr2Cl, excellent agreement with the values reported in Montzka et al. (2011) is found, while being slightly higher than previous studies from our group based on balloon-borne measurements.

The Halogen Bond

PubMed Central

2016-01-01

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design. PMID:26812185

Adsorption of halogens on metal surfaces

NASA Astrophysics Data System (ADS)

Andryushechkin, B. V.; Pavlova, T. V.; Eltsov, K. N.

2018-06-01

This paper presents a review of the experimental and theoretical investigations of halogen interaction with metal surfaces. The emphasis was placed on the recent measurements performed with a scanning tunneling microscope in combination with density functional theory calculations. The surface structures formed on metal surface after halogen interaction are classified into three groups: chemisorbed monolayer, surface halide, bulk-like halide. Formation of monolayer structures is described in terms of surface phase transitions. Surface halide phases are considered to be intermediates between chemisorbed halogen and bulk halide. The modern theoretical approaches in studying the dynamics of metal halogenation reactions are also presented.

FT-Raman spectroscopy study of organic matrix degradation in nanofilled resin composite.

PubMed

Soares, Luís Eduardo Silva; Nahórny, Sídnei; Martin, Airton Abrahão

2013-04-01

This in vitro study evaluated the effect of light curing unit (LCU) type, mouthwashes, and soft drink on chemical degradation of a nanofilled resin composite. Samples (80) were divided into eight groups: halogen LCU, HS--saliva (control); HPT--Pepsi Twist®; HLC--Listerine®; HCP--Colgate Plax®; LED LCU, LS--saliva (control); LPT--Pepsi Twist®; LLC--Listerine®; LCP--Colgate Plax®. The degree of conversion analysis and the measure of the peak area at 2,930 cm-1 (organic matrix) of resin composite were done by Fourier-transform Raman spectroscopy (baseline, after 7 and 14 days). The data were subjected to multifactor analysis of variance (ANOVA) at a 95% confidence followed by Tukey's HSD post-hoc test. The DC ranged from 58.0% (Halogen) to 59.3% (LED) without significance. Differences in the peak area between LCUs were found after 7 days of storage in S and PT. A marked increase in the peak intensity of HLC and LLC groups was found. The soft-start light-activation may influence the chemical degradation of organic matrix in resin composite. Ethanol contained in Listerine® Cool Mint mouthwash had the most significant degradation effect. Raman spectroscopy is shown to be a useful tool to investigate resin composite degradation.

Effects of thermal treatment on halogenated disinfection by-products in drinking water.

PubMed

Wu, W W; Benjamin, M M; Korshin, G V

2001-10-01

The influence of heating or boiling on the formation and behavior of disinfection by-products (DBPs) was investigated in DBP-spiked reagent water, municipal tap water, and synthetic water containing chlorinated aquatic humic substances. Thermal cleavage of larger halogenated species leads to both formation of smaller chlorinated molecules (including THMs and HAAs) and dechlorination of organics. In parallel with their formation from larger molecules, THMs can be volatilized, and this latter process dominates the change in their concentration when water is boiled. HAAs are not volatile, but they can be destroyed by chemical reactions at elevated temperatures, with the net effect being loss of trihalogenated HAAs and either formation or loss of less chlorinated HAAs. Although other identifiable DBPs can be generated at slightly elevated temperatures, in most cases their concentrations decline dramatically when the solution is heated.

Key parameters for behaviour related to source separation of household organic waste: A case study in Hanoi, Vietnam.

PubMed

Kawai, Kosuke; Huong, Luong Thi Mai

2017-03-01

Proper management of food waste, a major component of municipal solid waste (MSW), is needed, especially in developing Asian countries where most MSW is disposed of in landfill sites without any pretreatment. Source separation can contribute to solving problems derived from the disposal of food waste. An organic waste source separation and collection programme has been operated in model areas in Hanoi, Vietnam, since 2007. This study proposed three key parameters (participation rate, proper separation rate and proper discharge rate) for behaviour related to source separation of household organic waste, and monitored the progress of the programme based on the physical composition of household waste sampled from 558 households in model programme areas of Hanoi. The results showed that 13.8% of 558 households separated organic waste, and 33.0% discharged mixed (unseparated) waste improperly. About 41.5% (by weight) of the waste collected as organic waste was contaminated by inorganic waste, and one-third of the waste disposed of as organic waste by separators was inorganic waste. We proposed six hypothetical future household behaviour scenarios to help local officials identify a final or midterm goal for the programme. We also suggested that the city government take further actions to increase the number of people participating in separating organic waste, improve the accuracy of separation and prevent non-separators from discharging mixed waste improperly.

40 CFR 63.2465 - What requirements must I meet for process vents that emit hydrogen halide and halogen HAP or HAP...

Code of Federal Regulations, 2014 CFR

2014-07-01

... process vents that emit hydrogen halide and halogen HAP or HAP metals? 63.2465 Section 63.2465 Protection... hydrogen halide and halogen HAP or HAP metals? (a) You must meet each emission limit in Table 3 to this...) of this section. (b) If any process vents within a process emit hydrogen halide and halogen HAP, you...

40 CFR 63.2465 - What requirements must I meet for process vents that emit hydrogen halide and halogen HAP or HAP...

Code of Federal Regulations, 2013 CFR

2013-07-01

... process vents that emit hydrogen halide and halogen HAP or HAP metals? 63.2465 Section 63.2465 Protection... hydrogen halide and halogen HAP or HAP metals? (a) You must meet each emission limit in Table 3 to this...) of this section. (b) If any process vents within a process emit hydrogen halide and halogen HAP, you...

40 CFR 63.2465 - What requirements must I meet for process vents that emit hydrogen halide and halogen HAP or HAP...

Code of Federal Regulations, 2012 CFR

2012-07-01

... process vents that emit hydrogen halide and halogen HAP or HAP metals? 63.2465 Section 63.2465 Protection... hydrogen halide and halogen HAP or HAP metals? (a) You must meet each emission limit in Table 3 to this...) of this section. (b) If any process vents within a process emit hydrogen halide and halogen HAP, you...

A metagenomic-based survey of microbial (de)halogenation potential in a German forest soil

PubMed Central

Weigold, Pascal; El-Hadidi, Mohamed; Ruecker, Alexander; Huson, Daniel H.; Scholten, Thomas; Jochmann, Maik; Kappler, Andreas; Behrens, Sebastian

2016-01-01

In soils halogens (fluorine, chlorine, bromine, iodine) are cycled through the transformation of inorganic halides into organohalogen compounds and vice versa. There is evidence that these reactions are microbially driven but the key enzymes and groups of microorganisms involved are largely unknown. Our aim was to uncover the diversity, abundance and distribution of genes encoding for halogenating and dehalogenating enzymes in a German forest soil by shotgun metagenomic sequencing. Metagenomic libraries of three soil horizons revealed the presence of genera known to be involved in halogenation and dehalogenation processes such as Bradyrhizobium or Pseudomonas. We detected a so far unknown diversity of genes encoding for (de)halogenating enzymes in the soil metagenome including specific and unspecific halogenases as well as metabolic and cometabolic dehalogenases. Genes for non-heme, no-metal chloroperoxidases and haloalkane dehalogenases were the most abundant halogenase and dehalogenase genes, respectively. The high diversity and abundance of (de)halogenating enzymes suggests a strong microbial contribution to natural halogen cycling. This was also confirmed in microcosm experiments in which we quantified the biotic formation of chloroform and bromoform. Knowledge on microorganisms and genes that catalyze (de)halogenation reactions is critical because they are highly relevant to industrial biotechnologies and bioremediation applications. PMID:27353292

Abiotic Formation of Methyl Halides in the Terrestrial Environment

NASA Astrophysics Data System (ADS)

Keppler, F.

2011-12-01

Methyl chloride and methyl bromide are the most abundant chlorine and bromine containing organic compounds in the atmosphere. Since both compounds have relatively long tropospheric lifetimes they can effectively transport halogen atoms from the Earth's surface, where they are released, to the stratosphere and following photolytic oxidation form reactive halogen gases that lead to the chemical destruction of ozone. Methyl chloride and methyl bromide account for more than 20% of the ozone-depleting halogens delivered to the stratosphere and are predicted to grow in importance as the chlorine contribution to the stratosphere from anthropogenic CFCs decline. Today methyl chloride and methyl bromide originate mainly from natural sources with only a minor fraction considered to be of anthropogenic origin. However, until as recently as 2000 most of the methyl chloride and methyl bromide input to the atmosphere was considered to originate from the oceans, but investigations in recent years have clearly demonstrated that terrestrial sources such as biomass burning, wood-rotting fungi, coastal salt marshes, tropical vegetation and organic matter degradation must dominate the atmospheric budgets of these trace gases. However, many uncertainties still exist regarding strengths of both sources and sinks, as well as the mechanisms of formation of these naturally occurring halogenated gases. A better understanding of the atmospheric budget of both methyl chloride and methyl bromide is therefore required for reliable prediction of future ozone depletion. Biotic and abiotic methylation processes of chloride and bromide ion are considered to be the dominant pathways of formation of these methyl halides in nature. In this presentation I will focus on abiotic formation processes in the terrestrial environment and the potential parameters that control their emissions. Recent advances in our understanding of the abiotic formation pathway of methyl halides will be discussed. This will include a consideration on how stable isotope studies assisted advancements in this subject area. For example, it has been shown that the methoxyl groups of lignin and pectin which together constitute the bulk of the C1 plant pool have a carbon isotope signature significantly depleted in 13C. Plant-derived C1 volatile organic compounds (VOCs) are also highly depleted in 13C compared with Cn+1 VOCs. These observations suggest that the plant methoxyl pool is the predominant source of methyl halides released from senescent and dead plant litter. The distinct 13C depletion of plant methoxyl groups and naturally produced methyl halides may provide a helpful tool in constraining complex environmental processes and therefore improve our understanding of the global cycles of atmospheric methyl halides.

Structures and electronic states of halogen-terminated graphene nano-flakes

NASA Astrophysics Data System (ADS)

Tachikawa, Hiroto; Iyama, Tetsuji

2015-12-01

Halogen-functionalized graphenes are utilized as electronic devices and energy materials. In the present paper, the effects of halogen-termination of graphene edge on the structures and electronic states of graphene flakes have been investigated by means of density functional theory (DFT) method. It was found that the ionization potential (Ip) and electron affinity of graphene (EA) are blue-shifted by the halogen termination, while the excitation energy is red-shifted. The drastic change showed a possibility as electronic devices such as field-effect transistors. The change of electronic states caused by the halogen termination of graphene edge was discussed on the basis of the theoretical results.

40 CFR 268.38 - Waste specific prohibitions-newly identified organic toxicity characteristic wastes and newly...

Code of Federal Regulations, 2010 CFR

2010-07-01

... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene production wastes. (a) Effective December 19, 1994, the wastes specified in 40...

The relation between molecular structure and biological activity among mononitrophenols containing halogens

USGS Publications Warehouse

Applegate, Vernon C.; Johnson, B.G.H.; Smith, Manning A.

1966-01-01

The results of tests of the biological activity of certain nitrophenols containing halogen are reported. Some of these are shown to be significantly more toxic to larvae of the sea lamprey (Petromyzon marinus L.) than to fishes. It is proposed that the death of lamprey larvae exposed to these compounds results from an acute hypotension (shock) with concomitant circulatory and respiratory failure. Rainbow trout (Salmo gairdneri), on the other hand, appear to die, at higher concentrations of the toxin, due to a chemically-caused mechanical interference with respiration through the gills. A systematic series of studies of mononitrophenols containing halogens disclosed that those phenols having the nitro group in the para-position and a halogen atom or group in the meta-position are generally more toxic to lampreys than to fish. The halogens or halogen groups used in this study were fluorine, chlorine, bromine, and trifluormethyl. The same substituents in other positions only occasionally gave rise to selectively toxic compounds. The relationship between the selectively active class of nitrophenols containing halogens and other related structures is discussed.

Prediction of enthalpy and standard Gibbs energy of vaporization of haloaromatics from atomic properties.

PubMed

Monte, M J S; Almeida, A R R P; Liebman, J F

2015-11-01

Halogenated benzenes form a class of pollutants with a huge number of members - 1504 distinct benzene compounds, where one or more hydrogen atoms are replaced by halogens, may exist theoretically. This study presents a user friendly method for accurate prediction of vapor pressures and enthalpies of vaporization, at 298.15 K, of any mono or poly halobenzene compound. The derived equations for the prediction of those vaporization properties depend just on the number of each constituent halogen atom. This is a consequence of the absence of intramolecular interactions between the halogen atoms, revealed after examining vaporization results of ca. 40 halogenated benzenes. In order to rationalize the estimation equations, the contribution of the halogen atoms for the referred to above properties of vaporization was decomposed into two atomic properties - the volume and electron affinity. Extension of the applicability of the estimation method to substituted benzenes containing other substituent groups beyond halogen atoms as well as to some polycyclic aromatic species was tested with success. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigating the potential role of persistent organic pollutants in Hawaiian green sea turtle fibropapillomatosis

USGS Publications Warehouse

Keller, Jennifer M.; Balazs, George H.; Nilsen, Frances; Rice, Marc; Work, Thierry M.; Jensen, Brenda A.

2014-01-01

It has been hypothesized for decades that environmental pollutants may contribute to green sea turtle fibropapillomatosis (FP), possibly through immunosuppression leading to greater susceptibility to the herpesvirus, the putative causative agent of this tumor-forming disease. To address this question, we measured concentrations of 164 persistent organic pollutants (POPs) and halogenated phenols in 53 Hawaiian green turtle (Chelonia mydas) plasma samples archived by the Biological and Environmental Monitoring and Archival of Sea Turtle Tissues (BEMAST) project at the National Institute of Standards and Technology Marine Environmental Specimen Bank. Four groups of turtles were examined: free-ranging turtles from Kiholo Bay (0% FP, Hawaii), Kailua Bay (low FP, 8%, Oahu), and Kapoho Bay (moderate FP, 38%, Hawaii) and severely tumored stranded turtles that required euthanasia (high FP, 100%, Main Hawaiian Islands). Four classes of POPs and seven halogenated phenols were detected in at least one of the turtles, and concentrations were low (often <200 pg/g wet mass). The presence of halogenated phenols in sea turtles is a novel discovery; their concentrations were higher than most man-made POPs, suggesting that the source of most of these compounds was likely natural (produced by the algal turtle diet) rather than metabolites of man-made POPs. None of the compounds measured increased in concentration with increasing prevalence of FP across the four groups of turtles, suggesting that these 164 compounds are not likely primary triggers for the onset of FP. However, the stranded, severely tumored, emaciated turtle group (n = 14) had the highest concentrations of POPs, which might suggest that mobilization of contaminants with lipids into the blood during late-stage weight loss could contribute to the progression of the disease. Taken together, these data suggest that POPs are not a major cofactor in causing the onset of FP.

Investigating the potential role of persistent organic pollutants in Hawaiian green sea turtle fibropapillomatosis.

PubMed

Keller, Jennifer M; Balazs, George H; Nilsen, Frances; Rice, Marc; Work, Thierry M; Jensen, Brenda A

2014-07-15

It has been hypothesized for decades that environmental pollutants may contribute to green sea turtle fibropapillomatosis (FP), possibly through immunosuppression leading to greater susceptibility to the herpesvirus, the putative causative agent of this tumor-forming disease. To address this question, we measured concentrations of 164 persistent organic pollutants (POPs) and halogenated phenols in 53 Hawaiian green turtle (Chelonia mydas) plasma samples archived by the Biological and Environmental Monitoring and Archival of Sea Turtle Tissues (BEMAST) project at the National Institute of Standards and Technology Marine Environmental Specimen Bank. Four groups of turtles were examined: free-ranging turtles from Kiholo Bay (0% FP, Hawaii), Kailua Bay (low FP, 8%, Oahu), and Kapoho Bay (moderate FP, 38%, Hawaii) and severely tumored stranded turtles that required euthanasia (high FP, 100%, Main Hawaiian Islands). Four classes of POPs and seven halogenated phenols were detected in at least one of the turtles, and concentrations were low (often <200 pg/g wet mass). The presence of halogenated phenols in sea turtles is a novel discovery; their concentrations were higher than most man-made POPs, suggesting that the source of most of these compounds was likely natural (produced by the algal turtle diet) rather than metabolites of man-made POPs. None of the compounds measured increased in concentration with increasing prevalence of FP across the four groups of turtles, suggesting that these 164 compounds are not likely primary triggers for the onset of FP. However, the stranded, severely tumored, emaciated turtle group (n=14) had the highest concentrations of POPs, which might suggest that mobilization of contaminants with lipids into the blood during late-stage weight loss could contribute to the progression of the disease. Taken together, these data suggest that POPs are not a major cofactor in causing the onset of FP.

Two-dimensional on-line detection of brominated and iodinated volatile organic compounds by ECD and ICP-MS after GC separation.

PubMed

Schwarz, A; Heumann, K G

2002-09-01

Inductively coupled plasma-mass spectrometry (ICP-MS) was coupled to a gas chromatographic (GC) system with electron capture detector (ECD), which enables relatively easy characterization and quantification of brominated and iodinated (halogenated) volatile organic compounds (HVOCs) in aquatic and air samples. The GC-ECD system is connected in series with an ICP-MS by a directly heated transfer line and an outlet port-hole for elimination of the ECD make-up gas during ignition of the plasma. The hyphenated GC-ECD/ICP-MS system provides high selectivity and sensitivity for monitoring individual HVOCs under fast chromatographic conditions. The ECD is most sensitive for the detection of chlorinated and brominated but the ICP-MS for iodinated compounds. The greatest advantage of the use of an ICP-MS is its element-specific detection, which allows clear identification of compounds in most cases. The absolute detection limits for ICP-MS are 0.5 pg for iodinated, 10 pg for brominated, and 50 pg for chlorinated HVOCs with the additional advantage that calibration is almost independent on different compounds of the same halogen. In contrast to that detection limits for ECD vary for the different halogenated compounds and lie in the range of 0.03-11 pg. The two-dimensional GC-ECD/ICP-MS instrumentation is compared with electron impact mass spectrometry (EI-MS) and microwave induced plasma atomic emission detection (MIP-AED). Even if EI-MS has additional power in identifying unknown peaks by its scan mode, the detection limits are much higher compared with GC-ECD/ICP-MS, whereas the selective ion monitoring mode (SIM) reaches similar detection limits. The MIP-AED detection limits are at the same level as EI-MS in the scan mode.

Application of bioinformatics tools and databases in microbial dehalogenation research (a review).

PubMed

Satpathy, R; Konkimalla, V B; Ratha, J

2015-01-01

Microbial dehalogenation is a biochemical process in which the halogenated substances are catalyzed enzymatically in to their non-halogenated form. The microorganisms have a wide range of organohalogen degradation ability both explicit and non-specific in nature. Most of these halogenated organic compounds being pollutants need to be remediated; therefore, the current approaches are to explore the potential of microbes at a molecular level for effective biodegradation of these substances. Several microorganisms with dehalogenation activity have been identified and characterized. In this aspect, the bioinformatics plays a key role to gain deeper knowledge in this field of dehalogenation. To facilitate the data mining, many tools have been developed to annotate these data from databases. Therefore, with the discovery of a microorganism one can predict a gene/protein, sequence analysis, can perform structural modelling, metabolic pathway analysis, biodegradation study and so on. This review highlights various methods of bioinformatics approach that describes the application of various databases and specific tools in the microbial dehalogenation fields with special focus on dehalogenase enzymes. Attempts have also been made to decipher some recent applications of in silico modeling methods that comprise of gene finding, protein modelling, Quantitative Structure Biodegradibility Relationship (QSBR) study and reconstruction of metabolic pathways employed in dehalogenation research area.

Process for functionalizing alkanes

DOEpatents

Bergman, Robert G.; Janowicz, Andrew H.; Periana, Roy A.

1988-01-01

Process for functionalizing saturated hydrocarbons comprising: (a) reacting said saturated hydrocarbons of the formula: R.sub.1 H wherein H represents a hydrogen atom; and R.sub.1 represents a saturated hydrocarbon radical, with a metal complex of the formula: CpRh[P(R.sub.2).sub.3 ]H.sub.2 wherein Cp represents a cyclopentadienyl or alkylcyclopentadienyl radical; Rh represents a rhodium atom; P represents a phosphorus atom; R.sub.2 represents a hydrocarbon radical; H represents a hydrogen atom, in the presence of ultraviolet radiation to form a hydridoalkyl complex of the formula: CpRh[P(R.sub.2).sub.3 ](R.sub.1)H (b) reacting said hydridoalkyl complex with an organic halogenating agent such as a tetrahalomethane or a haloform of the formulas: CX'X''X'''X'''' or CHX'X''X''' wherein X', X'', X'", X"" represent halogens selected from bromine, iodine or chlorine atom, at a temperature in the range of about -60.degree. to -17.degree. C. to form the corresponding haloalkyl complex of step (a) having the formula: CpRhPMe.sub.3 RX; and, (c) reacting said haloalkyl complex formed in (b) with halogen (X.sub.2) at a temperature in the range of about -60.degree. to 25.degree. C. (i.e., ambient) to form a functional haloalkyl compound.

40 CFR 63.128 - Transfer operations provisions-test methods and procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... using a scrubber or other halogen reduction device to reduce the vent stream halogen atom mass emission...)(2) shall determine the halogen atom mass emission rate prior to the combustor according to the...

40 CFR 63.128 - Transfer operations provisions-test methods and procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... using a scrubber or other halogen reduction device to reduce the vent stream halogen atom mass emission...)(2) shall determine the halogen atom mass emission rate prior to the combustor according to the...

40 CFR 63.128 - Transfer operations provisions-test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... using a scrubber or other halogen reduction device to reduce the vent stream halogen atom mass emission...)(2) shall determine the halogen atom mass emission rate prior to the combustor according to the...

40 CFR 63.128 - Transfer operations provisions-test methods and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... using a scrubber or other halogen reduction device to reduce the vent stream halogen atom mass emission...)(2) shall determine the halogen atom mass emission rate prior to the combustor according to the...

40 CFR 63.128 - Transfer operations provisions-test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... using a scrubber or other halogen reduction device to reduce the vent stream halogen atom mass emission...)(2) shall determine the halogen atom mass emission rate prior to the combustor according to the...

Magnesium Bisamide-Mediated Halogen Dance of Bromothiophenes.

PubMed

Yamane, Yoshiki; Sunahara, Kazuhiro; Okano, Kentaro; Mori, Atsunori

2018-03-16

A magnesium bisamide-mediated halogen dance of bromothiophenes is described. The thienylmagnesium species generated in situ is more stable than the corresponding thienyllithium species, which was applied to trap the transient anion species with several electrophiles, such as allyl iodide, phenyl isocyanate, and tributylstannyl chloride. The utility of the magnesium bisamide-mediated halogen dance is useful in the concise synthesis of a medicinally advantageous compound via a one-pot, ester-directed halogen dance/Negishi cross coupling.

Evidence for Interfacial Halogen Bonding.

PubMed

Swords, Wesley B; Simon, Sarah J C; Parlane, Fraser G L; Dean, Rebecca K; Kellett, Cameron W; Hu, Ke; Meyer, Gerald J; Berlinguette, Curtis P

2016-05-10

A homologous series of donor-π-acceptor dyes was synthesized, differing only in the identity of the halogen substituents about the triphenylamine (TPA; donor) portion of each molecule. Each Dye-X (X=F, Cl, Br, and I) was immobilized on a TiO2 surface to investigate how the halogen substituents affect the reaction between the light-induced charge-separated state, TiO2 (e(-) )/Dye-X(+) , with iodide in solution. Transient absorption spectroscopy showed progressively faster reactivity towards nucleophilic iodide with more polarizable halogen substituents: Dye-F < Dye-Cl < Dye-Br < Dye-I. Given that all other structural and electronic properties for the series are held at parity, with the exception of an increasingly larger electropositive σ-hole on the heavier halogens, the differences in dye regeneration kinetics for Dye-Cl, Dye-Br, and Dye-I are ascribed to the extent of halogen bonding with the nucleophilic solution species. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multifunctional silicon surfaces: reaction of dichlorocarbene generated from Seyferth reagent with hydrogen-terminated silicon (111) surfaces.

PubMed

Liu, Wenjun; Sharp, Ian D; Tilley, T Don

2014-01-14

Insertion of dichlorocarbene (:CCl2), generated by decomposition of the Seyferth reagent PhHgCCl2Br, into the Si-H bond of a tertiary silane to form a Si-CCl2H group is an efficient homogeneous, molecular transformation. A heterogeneous version of this reaction, between PhHgCCl2Br and a silicon (111) surface terminated by tertiary Si-H bonds, was studied using a combination of surface-sensitive infrared and X-ray photoelectron spectroscopies. The insertion of dichlorocarbene into surface Si-H bonds parallels the corresponding reaction of silanes in solution, to produce surface-bound dichloromethyl groups (Si-CCl2H) covering ∼25% of the silicon surface sites. A significant fraction of the remaining Si-H bonds on the surface was converted to Si-Cl/Br groups during the same reaction, with PhHgCCl2Br serving as a halogen atom source. The presence of two distinct environments for the chlorine atoms (Si-CCl2H and Si-Cl) and one type of bromine atom (Si-Br) was confirmed by Cl 2p, Br 3d, and C 1s X-ray photoelectron spectroscopy. The formation of reactive, halogen-terminated atop silicon sites was also verified by reaction with sodium azide or the Grignard reagent (CH3MgBr), to produce Si-N3 or Si-Me functionalities, respectively. Thus, reaction of a hydrogen-terminated silicon (111) surface with PhHgCCl2Br provides a facile route to multifunctional surfaces possessing both stable silicon-carbon and labile silicon-halogen sites, in a single pot synthesis. The reactive silicon-halogen groups can be utilized for subsequent transformations and, potentially, the construction of more complex organic-silicon hybrid systems.

Noble gas isotopes and halogens in volatile-rich inclusions in diamonds

NASA Technical Reports Server (NTRS)

Burgess, Raymond; Turner, Grenville

1994-01-01

Application of the (40)Ar-(39)Ar method and noble gas studies to diamonds has increased our understanding of their age relationships to the host kimberlite or lamproite, and of the source and composition of volatile-rich fluids in the upper mantle. The properties of diamond (inert, high mechanical strength and low gas diffusivities) means they are especially useful samples for studying gases trapped deep within the earth (less than 150 km) as they are unlikely to have undergone loss or exchange of entrapped material since formation. Volatile-rich fluids (H2O-CO2) are important agents for metasomatic processes in the upper mantle, and the noble gases and halogens preferentially partition into this phase leading to a strong geochemical coherence between these groups of elements. The abundances of the halogens in the major reservoirs of the Earth shows a marked progression from chlorine, concentrated in the oceans, through to iodine which, through its affinity to organic material, is concentrated mainly in sediments. Abundances in the upper mantle are low. This is particularly true for iodine which is of special interest in view of its potential significance as an indicator of sediment recycling and by way of its link to (129)Xe amomalies in the mantle through the low extinct isotope (129)I. Extensions of the (40)Ar-(39)Ar technique enable measurements of halogens and other elements (K, Ca, Ba, U) by production of noble gas isotopes from these species during neutron irradiation. Samples analyzed in this way include 15 coated stones from an unknown source in Zaire, 3 boarts from the Jwaneng and 1 boart from the Orapa kimberlites, both in Botswana.

Intrinsic chemiluminescence production from the degradation of haloaromatic pollutants during environmentally-friendly advanced oxidation processes: Mechanism, structure-activity relationship and potential applications.

PubMed

Zhu, Benzhan; Shen, Chen; Gao, Huiying; Zhu, Liya; Shao, Jie; Mao, Li

2017-12-01

The ubiquitous distribution of halogenated aromatic compounds (XAr) coupled with their carcinogenicity has raised public concerns on their potential risks to both human health and the ecosystem. Recently, advanced oxidation processes (AOPs) have been considered as an "environmentally-friendly" technology for the remediation and destruction of such recalcitrant and highly toxic XAr. During our study on the mechanism of metal-independent production of hydroxyl radicals (OH) by halogenated quinones and H 2 O 2 , we found, unexpectedly, that an unprecedented OH-dependent two-step intrinsic chemiluminescene (CL) can be produced by H 2 O 2 and tetrachloro-p-benzoquinone, the major carcinogenic metabolite of the widely used wood preservative pentachlorophenol. Further investigations showed that, in all OH-generating systems, CL can also be produced not only by pentachlorophenol and all other halogenated phenols, but also by all XAr tested. A systematic structure-activity relationship study for all 19 chlorophenolic congeners showed that the CL increased with an increasing number of Cl-substitution in general. More importantly, a relatively good correlation was observed between the formation of quinoid/semiquinone radical intermediates and CL generation. Based on these results, we propose that OH-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual CL production; and a rapid, sensitive, simple, and effective CL method was developed not only to detect and quantify trace amount of XAr, but also to provide useful information for predicting the toxicity or monitoring real-time degradation kinetics of XAr. These findings may have broad chemical, environmental and biological implications for future studies on halogenated aromatic persistent organic pollutants. Copyright © 2017. Published by Elsevier B.V.

Effect of B-ring substitution pattern on binding mode of propionamide selective androgen receptor modulators.

PubMed

Bohl, Casey E; Wu, Zengru; Chen, Jiyun; Mohler, Michael L; Yang, Jun; Hwang, Dong Jin; Mustafa, Suni; Miller, Duane D; Bell, Charles E; Dalton, James T

2008-10-15

Selective androgen receptor modulators (SARMs) are essentially prostate sparing androgens, which provide therapeutic potential in osteoporosis, male hormone replacement, and muscle wasting. Herein we report crystal structures of the androgen receptor (AR) ligand-binding domain (LBD) complexed to a series of potent synthetic nonsteroidal SARMs with a substituted pendant arene referred to as the B-ring. We found that hydrophilic B-ring para-substituted analogs exhibit an additional region of hydrogen bonding not seen with steroidal compounds and that multiple halogen substitutions affect the B-ring conformation and aromatic interactions with Trp741. This information elucidates interactions important for high AR binding affinity and provides new insight for structure-based drug design.

Optical monitoring of Disinfection By-product Precursors with Fluorescence Excitation-Emission Mapping (F-EEM): Practical Application Issues for Drinking, Waste and Reuse Water Industry

NASA Astrophysics Data System (ADS)

Gilmore, A. M.

2012-12-01

Drinking water, wastewater and reuse plants must deal with regulations associated with bacterial contamination and halogen disinfection procedures that can generate harmful disinfection by-products (DBPs) including trihalomethanes (THMs), haloacetic acids (HOAAs) and other compounds. The natural fluorescent chromophoric dissolved organic matter (CDOM) is regulated as the major DBP precursor. This study outlines the advantages and current limitations associated with optical monitoring of water treatment processes using tcontemporary Fluorescence Excitation-Emission Mapping (F-EEM). The F-EEM method coupled with practical peak indexing and multi-variate analyses is potentially superior in terms of cost, speed and sensitivity over conventional total organic carbon (TOC) meters and specific UV-absorbance (SUVA) measurements. Hence there is strong interest in developing revised environmental regulations around the F-EEM technique instruments which can incidentally simultaneously measure the SUVA and DOC parameters. Importantly, the F-EEM technique, compared to the single-point TOC and SUVA signals can resolve CDOM classes distinguishing those that strongly cause DBPs. The F-EEM DBP prediction method can be applied to surface water sources to evaluate DBP potential as a function of the point sources and reservoir depth profiles. It can also be applied in-line to rapidly adjust DOC removal processes including sedimentation-flocculation, microfiltration, reverse-osmosis, and ozonation. Limitations and interferences for F-EEMs are discussed including those common to SUVA and TOC in contrast to the advantages including that F-EEMs are less prone to interferences from inorganic carbon and metal contaminations and require little if any chemical preparation. In conclusion, the F-EEM method is discussed in terms of not only the DBP problem but also as a means of predicting (concurrent to DBP monitoring) organic membrane fouling in water-reuse and desalination plants.

Assessment of anaerobic biodegradability of five different solid organic wastes

NASA Astrophysics Data System (ADS)

Kristanto, Gabriel Andari; Asaloei, Huinny

2017-03-01

The concept of waste to energy emerges as an alternative solution to increasing waste generation and energy crisis. In the waste to energy concept, waste will be used to produce renewable energy through thermochemical, biochemical, and physiochemical processes. In an anaerobic digester, organic matter brake-down due to anaerobic bacteria produces methane gas as energy source. The organic waste break-down is affected by various characteristics of waste components, such as organic matter content (C, N, O, H, P), solid contents (TS and VS), nutrients ratio (C/N), and pH. This research aims to analyze biodegradability and potential methane production (CH4) from organic waste largely available in Indonesia. Five solid wastes comprised of fecal sludge, cow rumen, goat farm waste, traditional market waste, and tofu dregs were analyzed which showed tofu dregs as waste with the highest rate of biodegradability compared to others since the tofu dregs do not contain any inhibitor which is lignin, have 2.7%VS, 14 C/N ratios and 97.3% organic matter. The highest cumulative methane production known as Biochemical Methane Potential was achieved by tofu dregs with volume of 77 ml during 30-day experiment which then followed by cow rumen, goat farm waste, and traditional market waste. Subsequently, methane productions were calculated through percentage of COD reduction, which showed the efficiency of 99.1% that indicates complete conversion of the high organic matter into methane.

Peptide selectivity between the PDZ domains of human pregnancy-related serine proteases (HtrA1, HtrA2, HtrA3, and HtrA4) can be reshaped by different halogen probes.

PubMed

Sun, Mei-Ling; Sun, Li-Mei; Wang, Yong-Qing

2018-06-01

The human HtrA family of serine proteases (HtrA1, HtrA2, HtrA3, and HtrA4) are the key enzymes associated with pregnancy and closely related to the development and progression of many pathological events. Previously, it was found that halogen substitution at the indole moiety of peptide Trp-1 residue can form a geometrically satisfactory halogen bond with the Drosophila discs large, zona occludens-1 (PDZ) domain of HtrA proteases. Here, we attempt to systematically investigate the effect of substitution with 4 halogen types and 2 indole positions on the binding affinity and specificity of peptide ligands to the 4 HtrA PDZ domains. The complex structures, interaction energies, halogen-bonding strength, and binding affinity of domain-peptide systems were modeled, analyzed, and measured via computational modeling and fluorescence-based assay. It is revealed that there is a compromise between the local rearrangement of halogen bond involving different halogen atoms and the global optimization of domain-peptide interaction; the substitution position is fundamentally important for peptide-binding affinity, while the halogen type can effectively shift peptide selectivity between the 4 domains. The HtrA1-PDZ and HtrA4-PDZ as well as HtrA2-PDZ and HtrA3-PDZ respond similarly to different halogen substitutions of peptide; -Br substitution at R2-position and -I substitution at R4-position are most effective in improving peptide selectivity for HtrA1-PDZ/HtrA4-PDZ and HtrA2-PDZ/HtrA3-PDZ, respectively; -F substitution would not address substantial effect on peptide selectivity for all the 4 domains. Consequently, the binding affinities of a native peptide ligand DSRIWWV -COOH as well as its 4 R2-halogenated counterparts were determined as 1.9, 1.4, 0.5, 0.27, and 0.92 μM, which are basically consistent with computational analysis. This study would help to rationally design selective peptide inhibitors of HtrA family members by using different halogen substitutions. Copyright © 2017 John Wiley & Sons, Ltd.

Analysis of gaseous SO2, CO2 and halogen species in volcanic plumes using a multirotor Unmanned Aerial Vehicle (UAV).

NASA Astrophysics Data System (ADS)

Rüdiger, J.; de Moor, M. J.; Tirpitz, L.; Bobrowski, N.; Gutmann, A.; Hoffmann, T.

2016-12-01

Volcanoes are a large source for several reactive atmospheric trace gases including sulfur and halogen containing species. The detailed understanding of volcanic plume chemistry is needed to draw information from gas measurements on subsurface processes. This knowledge is essential for using gas measurements as a monitoring tool for volcanic activity. The reactive bromine species bromine monoxide (BrO) is of particular interest, because BrO as well as SO2 are readily measurable from safe distance by spectroscopic remote sensing techniques. BrO is not directly emitted, but is formed in the plume by a multiphase reaction mechanism. The abundance of BrO changes as a function of the distance from the vent as well as the spatial position in the plume. The precursor substance for the formation of BrO is HBr with Br2 as an intermediate product. In this study we present the application of a UAV as a carrier for a remote-controlled sampling system for halogen species (Br2, HBr, BrCl, etc), based on the gas diffusion denuder technique, which allows speciation and enrichment by selective organic reactions. For the analysis of gaseous SO2 and CO2 an in-situ gas monitoring system was additionally mounted. This setup was deployed into the gas plumes of Stromboli Volcano (Italy) and Masaya Volcano (Nicaragua) in 2016, to investigate the halogen chemistry at distant locations in the plume further downwind to the emission source, which are in most cases not accessible by other approaches. The used quadrocopter (0.75 m in diameter) weighs 2.45 kg and lifts a payload of 1.3 kg. Flights into the plume were conducted with ascents of up to 900 m, starting at 500 to 800 m altitude. From telemetrically transmitted SO2 mixing ratios, areas of dense plume were localized to keep the UAV stationary for up to 10 minutes of sampling time. Herein we will present time and spatial resolved gas mixing ratio data for SO2, CO2 and halogen species for a downwind plume age of about 3 to 5 minutes.

Hydrophobic Organic Compounds in Hydraulic Fracturing Flowback Waters: Identification and Source Apportionment

NASA Astrophysics Data System (ADS)

Plata, D.; Shregglman, K.; Elsner, M.; Getzinger, G.; Ferguson, L.; Drollette, B.; Karatum, O.; Nelson, R. K.; Reddy, C. M.

2014-12-01

Current hydraulic fracturing technologies rely on organic chemicals to serve multiple critical functions, including corrosion inhibition, in situ gel formation, and friction reduction. While industrial users have disclosed several hundreds of compound and mixture identities, it is unclear which of these are used and where, in what proportion, and with what frequency. Furthermore, while flowback and production waters contain both fracturing additive and geogenic compounds, they may contain potential reaction byproducts as well. Here, we identified several hundred organic compounds present in six hydraulic fracturing flowback waters over the Fayetteville shale. Identifications were made via non-target analysis using two-dimensional gas chromatography with time of flight mass spectrometry for hydrophobic organic compounds and liquid chromatography- orbitrap mass spectrometry. Compound identities were confirmed using purchased standards when available. Using the SkyTruth database and the Waxman list of disclosed compounds, we assigned compounds as either fracturing-fluid-derived or geogenic (or both), or a putative transformation products thereof. Several unreported halogenated compounds were detected, including chlorinated, brominated, and iodated species that have no known natural sources. Control studies indicated that these could not be formed under typical laboratory or field storage conditions, suggesting that halogenation reactions may give rise to novel compounds in the subsurface, presumably via reaction between fracturing fluid additives and shale-derived brines. Further, the six samples were strikingly heterogeneous, reflecting the diversity in fracturing fluid composition and flowback handling procedures at the time of the study.

The importance of the southern ocean on distributions and lifetimes of non-methane organic compounds

NASA Astrophysics Data System (ADS)

Apel, E. C.; Asher, E.; Hills, A. J.; Hornbrook, R. S.; Emmons, L. K.; Blake, N. J.; Stephens, B. B.

2017-12-01

During the ORCAS (O2/N2 Ratio and CO2 Airborne Southern Ocean) campaign, a large number of volatile organic compounds (VOCs) were observed using Trace Organic Gas Analyzer (TOGA) including non-methane hydrocarbons (NMHCs), halogenated volatile organic compounds (HVOCs), oxygenated VOCs (OVOCs), alkyl nitrates, and nitriles. Mixing ratios of VOCs with known continental sources observed during ORCAS were very low in comparison to measurements made over tropical and mid-latitude Pacific Ocean using the same instrumentation during previous January-February field campaigns, TORERO (Tropical Ocean tRoposphere Exchange of Reactive halogen species and Oxygenated VOC, 2012) and CONTRAST (CONvective Transport of Active Species in the Tropics, 2014). The ORCAS dataset provides some of the first observations of Southern Hemisphere distributions of several of the most abundant non-methane VOCs in the atmosphere including acetone, hydrogen cyanide (HCN), methanol, and acetonitrile. Although the majority of the sources for these species are continental, the ocean's role as a sink for HCN and acetonitrile and as a net source or sink for methanol and acetone is not fully understood and this will be investigated using CAM-chem (Community Atmosophere model with chemistry). The southern oceans studied during ORCAS will provide key missing information on this and relationships of these VOCs to CO2 and O2 will provide a means to constrain the influence of continental emissions and transport from mid-latitudes on air masses encountered over the Southern Ocean.

Seasonal variations and source apportionment of complex polycyclic aromatic hydrocarbon mixtures in particulate matter in an electronic waste and urban area in South China.

PubMed

Chen, She-Jun; Wang, Jing; Wang, Tao; Wang, Ting; Mai, Bi-Xian; Simonich, Staci L Massey

2016-12-15

Complex polycyclic aromatic hydrocarbon (PAH) mixtures including parent PAHs, high molecular weight PAHs (MW 302 PAHs), and halogenated PAHs (HPAHs) were measured in particulate matter (PM) in an urban area and a rural electronic waste area in South China. The concentrations of MW < 302 PAHs at two sites were not significantly different with annual means of 23.2 ± 17.2 and 33.7 ± 29.0 ng/m 3 , respectively. However the concentrations of both MW 302 PAHs (5.35 ± 3.72 ng/m 3 ) and HPAH (49.9 pg/m 3 ) were significantly higher at the e-waste site than the urban site (2.81 ± 2.36 ng/m 3 and 28.2 ± 28.5 pg/m 3 ), suggesting e-waste recycling being a significant source of these PAHs. The majority of PAHs exhibited higher concentrations in winter and spring and lower concentrations in fall and summer. Meteorological conditions and increased emissions of PAHs in northern China due to domestic heating in colder seasons are important factors influencing the PAH seasonal variations. Source apportionment by the chemical mass balance (CMB) model indicated that residential stoves (coal combustion), industrial boilers (coal combustion), biomass burning, and vehicular emission accounted for 38 ± 14%, 30 ± 11%, 22 ± 22%, and 10 ± 7% of the PAHs in the urban PM, respectively. Comparable contributions from these sources were also observed for PM at the e-waste site. PAH emission factors are needed for primitive e-waste recycling to further understand the importance of this source to ambient air. Copyright © 2016 Elsevier B.V. All rights reserved.

Shear bond strength of a bracket-bonding system cured with a light-emitting diode or halogen-based light-curing unit at various polymerization times

PubMed Central

Gupta, Sanjay Prasad; Shrestha, Basanta Kumar

2018-01-01

Purpose To determine and compare the shear bond strength (SBS) of bracket-bonding system cured with light-emitting diode (LED) and halogen-based light-curing unit at various polymerization times. Materials and methods Ninety six human maxillary premolar teeth extracted for orthodontic purpose were divided into four groups, according to the light-curing unit and exposure times used. In the halogen group, the specimens were light cured for 20 and 40 seconds. In the LED group, the specimens were light cured for 5 and 10 seconds. Stainless steel brackets were bonded with Enlight bonding system, stored in distilled water at 37°C for 24 hours and then submitted to SBS testing in a universal testing machine at a crosshead speed of 0.5 mm/minute. Adhesive remnant index (ARI) was used to evaluate the amount of adhesive remaining on the teeth determined by stereomicroscope at 10× magnification. Results The highest mean SBS was obtained with the halogen 40 seconds (18.27 MPa) followed by halogen 20 seconds (15.36 MPa), LED 10 seconds (14.60 MPa) and least with LED 5 seconds (12.49 MPa) group. According to analysis of variance (ANOVA) and Tukey’s multiple-comparison test, SBS of halogen 20 seconds group was not significantly different from halogen 40 seconds group, LED 5 seconds group and LED 10 seconds group, whereas halogen 40 seconds group was significantly different from LED 5 seconds and LED 10 seconds group. The method of light curing did not influence the ARI, with score 2 being predominant. Conclusion Polymerization with both halogen and LED resulted in SBS values that were clinically acceptable for orthodontic treatment in all groups. Hence, for bonding orthodontic brackets, photoactivation with halogen for 20 seconds and LED for 5 seconds is suggested. PMID:29692633

Metal halogen battery system with multiple outlet nozzle for hydrate

DOEpatents

Bjorkman, Jr., Harry K.

1983-06-21

A metal halogen battery system, including at least one cell having a positive electrode and a negative electrode contacted by aqueous electrolyte containing the material of said metal and halogen, store means whereby halogen hydrate is formed and stored as part of an aqueous material, means for circulating electrolyte through the cell and to the store means, and conduit means for transmitting halogen gas formed in the cell to a hydrate former whereby the hydrate is formed in association with the store means, said store means being constructed in the form of a container which includes a filter means, said filter means being inoperative to separate the hydrate formed from the electrolyte, said system having, a hydrate former pump means associated with the store means and being operative to intermix halogen gas with aqueous electrolyte to form halogen hydrate, said hydrate former means including, multiple outlet nozzle means connected with the outlet side of said pump means and being operative to minimize plugging, said nozzle means being comprised of at least one divider means which is generally perpendicular to the rotational axes of gears within the pump means, said divider means acting to divide the flow from the pump means into multiple outlet flow paths.

Solid waste containing persistent organic pollutants in Serbia: From precautionary measures to the final treatment (case study).

PubMed

Stevanovic-Carapina, Hristina; Milic, Jelena; Curcic, Marijana; Randjelovic, Jasminka; Krinulovic, Katarina; Jovovic, Aleksandar; Brnjas, Zvonko

2016-07-01

Sustainable solid waste management needs more dedicated attention in respect of environmental and human health protection. Solid waste containing persistent organic pollutants is of special concern, since persistent organic pollutants are persistent, toxic and of high risk to human health and the environment. The objective of this investigation was to identify critical points in the Serbian system of solid waste and persistent organic pollutants management, to assure the life cycle management of persistent organic pollutants and products containing these chemicals, including prevention and final destruction. Data were collected from the Serbian competent authorities, and led us to identify preventive actions for solid waste management that should reduce or minimise release of persistent organic pollutants into the environment, and to propose actions necessary for persistent organic pollutants solid waste. The adverse impact of persistent organic pollutants is multidimensional. Owing to the lack of treatment or disposal plants for hazardous waste in Serbia, the only option at the moment to manage persistent organic pollutants waste is to keep it in temporary storage and when conditions are created (primarily financial), such waste should be exported for destruction in hazardous waste incinerators. Meanwhile, it needs to be assured that any persistent organic pollutants management activity does not negatively impact recycling flows or disturb progress towards a more circular economy in Serbia. © The Author(s) 2016.

Supramolecular amplification of amyloid self-assembly by iodination

NASA Astrophysics Data System (ADS)

Bertolani, Arianna; Pirrie, Lisa; Stefan, Loic; Houbenov, Nikolay; Haataja, Johannes S.; Catalano, Luca; Terraneo, Giancarlo; Giancane, Gabriele; Valli, Ludovico; Milani, Roberto; Ikkala, Olli; Resnati, Giuseppe; Metrangolo, Pierangelo

2015-06-01

Amyloid supramolecular assemblies have found widespread exploitation as ordered nanomaterials in a range of applications from materials science to biotechnology. New strategies are, however, required for understanding and promoting mature fibril formation from simple monomer motifs through easy and scalable processes. Noncovalent interactions are key to forming and holding the amyloid structure together. On the other hand, the halogen bond has never been used purposefully to achieve control over amyloid self-assembly. Here we show that single atom replacement of hydrogen with iodine, a halogen-bond donor, in the human calcitonin-derived amyloidogenic fragment DFNKF results in a super-gelator peptide, which forms a strong and shape-persistent hydrogel at 30-fold lower concentration than the wild-type pentapeptide. This is remarkable for such a modest perturbation in structure. Iodination of aromatic amino acids may thus develop as a general strategy for the design of new hydrogels from unprotected peptides and without using organic solvents.

Enantioselective decarboxylative chlorination of β-ketocarboxylic acids

PubMed Central

Shibatomi, Kazutaka; Kitahara, Kazumasa; Sasaki, Nozomi; Kawasaki, Yohei; Fujisawa, Ikuhide; Iwasa, Seiji

2017-01-01

Stereoselective halogenation is a highly useful organic transformation for multistep syntheses because the resulting chiral organohalides can serve as precursors for various medicinally relevant derivatives. Even though decarboxylative halogenation of aliphatic carboxylic acids is a useful and fundamental synthetic method for the preparation of a variety of organohalides, an enantioselective version of this reaction has not been reported. Here we report a highly enantioselective decarboxylative chlorination of β-ketocarboxylic acids to obtain α-chloroketones under mild organocatalytic conditions. The present method is also applicable for the enantioselective synthesis of tertiary α-chloroketones. The conversions of the resulting α-chloroketones into α-aminoketones and α-thio-substituted ketones via SN2 reactions at the tertiary carbon centres are also demonstrated. These results constitute an efficient approach for the synthesis of chiral organohalides and are expected to enhance the availability of enantiomerically enriched chiral compounds with heteroatom-substituted chiral stereogenic centres. PMID:28580951

Enantioselective decarboxylative chlorination of β-ketocarboxylic acids

NASA Astrophysics Data System (ADS)

Shibatomi, Kazutaka; Kitahara, Kazumasa; Sasaki, Nozomi; Kawasaki, Yohei; Fujisawa, Ikuhide; Iwasa, Seiji

2017-06-01

Stereoselective halogenation is a highly useful organic transformation for multistep syntheses because the resulting chiral organohalides can serve as precursors for various medicinally relevant derivatives. Even though decarboxylative halogenation of aliphatic carboxylic acids is a useful and fundamental synthetic method for the preparation of a variety of organohalides, an enantioselective version of this reaction has not been reported. Here we report a highly enantioselective decarboxylative chlorination of β-ketocarboxylic acids to obtain α-chloroketones under mild organocatalytic conditions. The present method is also applicable for the enantioselective synthesis of tertiary α-chloroketones. The conversions of the resulting α-chloroketones into α-aminoketones and α-thio-substituted ketones via SN2 reactions at the tertiary carbon centres are also demonstrated. These results constitute an efficient approach for the synthesis of chiral organohalides and are expected to enhance the availability of enantiomerically enriched chiral compounds with heteroatom-substituted chiral stereogenic centres.

[Application of quantum-chemical methods to prediction of the carcinogenicity of chemical substances].

PubMed

Zholdikova, Z I; Kharchevnikova, N V

2006-01-01

A version of logical-combinatorial JSM type intelligent system was used to predict the presence and the degree of a carcinogenic effect. This version was based on combined description of chemical substances including both structural and numeric parameters. The new version allows for the fact that the toxicity and danger caused by chemical substances often depend on their biological activation in the organism. The authors substantiate classifying chemicals according to their carcinogenic activity, and illustrate the use of the system to predict the carcinogenicity of polycyclic aromatic hydrocarbons using a model of bioactivation via the formation of diolepoxides, and the carcinogenicity of halogenated alkanes using a model of bioactivation via oxidative dehalogenation. The paper defined the boundary level of an energetic parameter, the exceeding of which correlated with the inhibition of halogenated alkanes's metabolism and the absence of carcinogenic activity.

Double-chamber electrode for spectrochemical determination of chlorine and other halogens

USGS Publications Warehouse

de Paiva, Azevedo; Specht, A.W.; Harner, R.S.

1954-01-01

A double-chamber, graphite electrode, suitable for d.c. arc determination of halogens by means of the alkaline earth halide bands, is described. An upper chamber holds the alkaline earth compound and an interconnected, lower chamber holds the halogen compound. This arrangement assures that there will be an abundance of alkaline earths in the arc by the time the halogen is volatilized from the lower chamber, and thereby promotes maximum emission of the alkaline earth halide bands. ?? 1954.

Substantial production of drosophilin A methyl ether (tetrachloro-1,4-dimethoxybenzene) by the lignicolous basidiomycete Phellinus badius in the heartwood of mesquite (Prosopis juliflora) trees

Treesearch

Laurence A.J. Garvie; Barry Wilkens; Thomas L. Groy; Jessie A. Glaeser

2015-01-01

Toxic organohalogen pollutants produced as byproducts of industrial processes, such as chloroform and polychlorinated dibenzo-p-dioxins, also have significant natural sources. A substantial terrestrial source of halogenated organics originates from fungal decay of wood and leaf litter. Here we show that the lignicolous basidiomycete ...

Vapor-Phase Catalytic Oxidation of Mixed Volatile Organic Compounds

DTIC Science & Technology

1989-09-01

18 3. Hopcalite . . . . . . . . . 18 4. Potassium Chloride/Copper Oxide . . . 19 5. Vanadium Pentoxide . . . . . . . 19 6. Potassium...decomposition of 19 halogenated hydrocarbons, associated with submarine burners, using a hopcalite catalyst. Bond, et al. (Reference 9) have studied the...The catalyst can be easily regenerated, but deactivation occurs within a matter of minutes. 3. Hopcalite This mineral, containing primarily CuD and

Engineering of air-stable Fe/C/Pd composite nanoparticles for environmental remediation applications

NASA Astrophysics Data System (ADS)

Haham, Hai; Grinblat, Judith; Sougrati, Moulay-Tahar; Stievano, Lorenzo; Margel, Shlomo

2015-09-01

The present manuscript presents a convenient method for the synthesis of iron/carbon (Fe/C) nanoparticles (NPs) coated with much smaller Pd NPs for the removal of halogenated organic pollutants. For this purpose, iron oxide/polyvinylpyrrolidone (IO/PVP) NPs were first prepared by the thermal decomposition of ferrocene mixed with PVP at 350 °C under an inert atmosphere. IO,Fe/C and Fe/C NPs coated with graphitic and amorphous carbon layers were then produced by annealing the IO/PVP NPs at 500 and 600 °C, respectively, under an inert atmosphere. The effect of the annealing temperature on the chemical composition, shape, crystallinity, surface area and magnetic properties of the IO/PVP, IO,Fe/C and Fe/C NPs has been elucidated. Air-stable Fe/C/Pd NPs were produced by mixing the precursor palladium acetate with the air-stable Fe/C NPs in ethanol. The obtained Fe/C/Pd NPs demonstrated significantly higher environmental activity than the Fe/C NPs on eosin Y, a model halogenated organic pollutant. The environmental activity of the Fe/C/Pd NPs also increased with their increasing Pd content.

Dehalogenation of persistent halogenated organic compounds: A review of computational studies and quantitative structure-property relationships.

PubMed

Luo, Jin; Hu, Jiwei; Wei, Xionghui; Fu, Liya; Li, Lingyun

2015-07-01

Dehalogenation is one of the highly important degradation reactions for halogenated organic compounds (HOCs) in the environment, which is also being developed as a potential type of the remediation technologies. In combination with the experimental results, intensive efforts have recently been devoted to the development of efficient theoretical methodologies (e.g. multi-scale simulation) to investigate the mechanisms for dehalogenation of HOCs. This review summarizes the structural characteristics of neutral molecules, anionic species and excited states of HOCs as well as their adsorption behavior on the surface of graphene and the Fe cluster. It discusses the key physiochemical properties (e.g. frontier orbital energies and thermodynamic properties) calculated at various levels of theory (e.g. semiempirical, ab initio, density functional theory (DFT) and the periodic DFT) as well as their connections to the reactivity and reaction pathway for the dehalogenation. This paper also reviews the advances in the linear and nonlinear quantitative structure-property relationship models for the dehalogenation kinetics of HOCs and in the mathematical modeling of the dehalogenation processes. Furthermore, prospects of further expansion and exploration of the current research fields are described in this article. Published by Elsevier Ltd.

Analysis of organochlorine compounds and extractable organic halogen in three subspecies of ringed seal from northeast Europe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostamo, A.; Medvedev, N.; Pellinen, J.

2000-04-01

Organochlorine compounds in blubber samples of the ringed seal (Phoca hispida saimensis, P. H. ladogensis, and P. h. hispida) were analyzed in order to estimate the state of pollution in three different water areas in Northeast Europe, namely, Lake Saimaa in Finland, Lake Lodoga, and the White Sea in Russia. Geographic differences in concentrations and in relative concentrations of tri- and tetrachlorocymenes, hexachlorobenzene, {alpha}-HCH, {beta}-HCH, {gamma}-HCH (Lindane), seven polychlorinated biphenyl (PCB) congeners, and p,p{prime}-DDT and its metabolites in ringed seals were compared. Concentrations of chlorinated hydrocarbons varied between the water areas. The highest concentrations were found in Saimaa ringed seals,more » followed by Lodaga ringed seals, and the lowest concentrations were detected in ringed seals from the White Sea. Extractable organic halogen (EOX) concentrations in blubber were also analyzed. The concentrations showed a geographic trend similar to those for the individual compounds identified. In Lakes Ladoga and Saimaa, the concentrations of EOX and chlorinated hydrocarbons in the blubber were dependent on the age and sex of the seals, but no such relationship was observed in samples from the White Sea.« less

Optical studies of photoactive states in mixed organic-inorganic hybrid perovskites stabilized in polymers

NASA Astrophysics Data System (ADS)

Kardynal, Beata; Xi, Lifei; Salim, Teddy; Borghardt, Sven; Stoica, Toma; Lam, Yeng Ming

2015-03-01

Mixed organic-inorganic hybrid perovskites MAX-PbY2(X,Y =I, Br,Cl) have been demonstrated as very attractive materials for absorbers of solar cells and active layers of light emitting diodes and optically driven lasers. The bandgap of the perovskites can be tuned by mixing halogen atoms in different ratios. In this presentation we study mixed MAX-PbY2(X,Y =I, Br, Cl) particles synthesized directly in protective polymer matrices as light emitters. Both, time integrated and time resolved photoluminescence have been used to study the materials. So synthesized MAX-PbX2 are very stable when measured at room temperature and in air with radiative recombination of photogenerated carriers as the main decay path. In contrast, MAX-PbY2 with mixed halogen atoms display luminescence from sub-bandgap states which saturate at higher excitation levels. The density of these states depends on the used polymer matrix and increases upon illumination. We further compare the MAX-PbY2 synthesized in polymers and as films and show that these states are inherent to the material rather than its microstructure. This works has been supported by EU NWs4LIGHT grant.

Scientific conferences: A big hello to halogen bonding

NASA Astrophysics Data System (ADS)

Erdelyi, Mate

2014-09-01

Halogen bonding connects a wide range of subjects -- from materials science to structural biology, from computation to crystal engineering, and from synthesis to spectroscopy. The 1st International Symposium on Halogen Bonding explored the state of the art in this fast-growing field of research.

DESTRUCTION OF HALOGENATED HYDROCARBONS WITH SOLVATED ELECTRONS IN THE PRESENCE OF WATER. (R826180)

EPA Science Inventory

Model halogenated aromatic and aliphatic hydrocarbons and halogenated phenols were dehalogenated in seconds by solvated electrons generated from sodium in both anhydrous liquid ammonia and ammonia/water solutions. The minimum sodium required to completely dehalogenate these mo...

Metal-Mediated Halogen Exchange in Aryl and Vinyl Halides: A Review

PubMed Central

Evano, Gwilherm; Nitelet, Antoine; Thilmany, Pierre; Dewez, Damien F.

2018-01-01

Halogenated arenes and alkenes are of prime importance in many areas of science, especially in the pharmaceutical, agrochemical, and chemical industries. While the simplest ones are commercially available, some of them are still hardly accessible depending on their substitution patterns and the nature of the halogen atom. Reactions enabling the selective and efficient replacement of the halogen atom of an aryl or alkenyl halide by another one, lighter, or heavier, are therefore of major importance since they can be used for example to turn a less reactive aryl/alkenyl chloride into the more reactive iodinated derivatives or, in a reversed sense, to block an undesired reactivity, for late-stage modifications or for the introduction of a radionuclide. If some halogen exchange reactions are possible with activated substrates, they usually require catalysis with metal complexes. Remarkably efficient processes have been developed for metal-mediated halogen exchange in aryl and vinyl halides: they are overviewed, in a comprehensive manner, in this review article. PMID:29755967

79/81Br nuclear quadrupole resonance spectroscopic characterization of halogen bonds in supramolecular assemblies.

PubMed

Cerreia Vioglio, P; Szell, P M J; Chierotti, M R; Gobetto, R; Bryce, D L

2018-05-28

Despite the applicability of solid-state NMR to study the halogen bond, the direct NMR detection of 79/81 Br covalently bonded to carbon remains impractical due to extremely large spectral widths, even at ultra-high magnetic fields. In contrast, nuclear quadrupole resonance (NQR) offers comparatively sharp resonances. Here, we demonstrate the abilities of 79/81 Br NQR to characterize the electronic changes in the C-Br···N halogen bonding motifs found in supramolecular assemblies constructed from 1,4-dibromotetrafluorobenzene and nitrogen-containing heterocycles. An increase in the bromine quadrupolar coupling constant is observed, which correlates linearly with the halogen bond distance ( d Br···N ). Notably, 79/81 Br NQR is able to distinguish between two symmetry-independent halogen bonds in the same crystal structure. This approach offers a rapid and reliable indication for the occurrence of a halogen bond, with experimental times limited only by the observation of 79/81 Br NQR resonances.

Metal-Mediated Halogen Exchange in Aryl and Vinyl Halides: a Review

NASA Astrophysics Data System (ADS)

Evano, Gwilherm; Nitelet, Antoine; Thilmany, Pierre; Dewez, Damien F.

2018-04-01

Halogenated arenes and alkenes are of prime importance in many areas of science, especially in the pharmaceutical, agrochemical and chemical industries. While the simplest ones are commercially available, some of them are still hardly accessible depending on their substitution patterns and the nature of the halogen atom. Reactions enabling the selective and efficient replacement of the halogen atom of an aryl or alkenyl halide by another one, lighter or heavier, are therefore of major importance since they can be used for example to turn a less reactive aryl/alkenyl chloride into the more reactive iodinated derivatives or, in a reversed sense, to block an undesired reactivity, for late-stage modifications or for the introduction of a radionuclide. If some halogen exchange reactions are possible with activated substrates, they usually require catalysis with metal complexes. Remarkably efficient processes have been developed for metal-mediated halogen exchange in aryl and vinyl halides: they are overviewed, in a comprehensive manner, in this review article.

Natural solar photolysis of total organic chlorine, bromine and iodine in water.

PubMed

Abusallout, Ibrahim; Hua, Guanghui

2016-04-01

Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters. Published by Elsevier Ltd.

Halogenated methanesulfonic acids: A new class of organic micropollutants in the water cycle.

PubMed

Zahn, Daniel; Frömel, Tobias; Knepper, Thomas P

2016-09-15

Mobile and persistent organic micropollutants may impact raw and drinking waters and are thus of concern for human health. To identify such possible substances of concern nineteen water samples from five European countries (France, Switzerland, The Netherlands, Spain and Germany) and different compartments of the water cycle (urban effluent, surface water, ground water and drinking water) were enriched with mixed-mode solid phase extraction. Hydrophilic interaction liquid chromatography - high resolution mass spectrometry non-target screening of these samples led to the detection and structural elucidation of seven novel organic micropollutants. One structure could already be confirmed by a reference standard (trifluoromethanesulfonic acid) and six were tentatively identified based on experimental evidence (chloromethanesulfonic acid, dichloromethanesulfonic acid, trichloromethanesulfonic acid, bromomethanesulfonic acid, dibromomethanesulfonic acid and bromochloromethanesulfonic acid). Approximated concentrations for these substances show that trifluoromethanesulfonic acid, a chemical registered under the European Union regulation REACH with a production volume of more than 100 t/a, is able to spread along the water cycle and may be present in concentrations up to the μg/L range. Chlorinated and brominated methanesulfonic acids were predominantly detected together which indicates a common source and first experimental evidence points towards water disinfection as a potential origin. Halogenated methanesulfonic acids were detected in drinking waters and thus may be new substances of concern. Copyright © 2016 Elsevier Ltd. All rights reserved.

Disinfection Pilot Trial for Little Miami WWTP | Science ...

EPA Pesticide Factsheets

There is a serious interest growing nationally towards the use of PAA at various stages of public waste water treatment facilities; one of such use is secondary waste water treatment. MSDGC is currently interested in improving efficiency and economic aspects of waste water treatment. MSDGC requested for ORD’s support to evaluate alternative cost-effective disinfectants. This report herein is based on the data generated from the field pilot test conducted at the Little Miami Wastewater Treatment Plant. Chlorine assisted disinfection of wastewaters created the concern regarding the formation of high levels of toxic halogenated disinfection byproducts (DBPs) detrimental to aquatic life and public health. Peracetic acid is emerging as a green alternative to chlorine and claimed to have economic and social benefits. In addition, it is a relatively simple retrofit to the existing chlorine treated wastewater treatment facilities. PAA is appealed to possess a much lower aquatic toxicity profile than chlorine and decays rapidly in the environment, even if overdosed. As a result, PAA generally does not need a quenching step, such as dechlorination, reducing process complexity, sodium pollution and cost. PAA treatment does not result in the formation of chlorinated disinfection by-products such as trihalomethanes (THMs), haloacetic acids and other byproducts such as cyanide and n-Nitrosodimethylamine (NDMA).

Methods of Responsibly Managing End-of-Life Foams and Plastics Containing Flame Retardants: Part I.

PubMed

Lucas, Donald; Petty, Sara M; Keen, Olya; Luedeka, Bob; Schlummer, Martin; Weber, Roland; Barlaz, Morton; Yazdani, Ramin; Riise, Brian; Rhodes, James; Nightingale, Dave; Diamond, Miriam L; Vijgen, John; Lindeman, Avery; Blum, Arlene; Koshland, Catherine P

2018-06-01

Flame retardants (FRs) are added to foams and plastics to comply with flammability standards and test requirements in products for household and industrial uses. When these regulations were implemented, potential health and environmental impacts of FR use were not fully recognized or understood. Extensive research in the past decades reveal that exposure to halogenated FRs, such as those used widely in furniture foam, is associated with and/or causally related to numerous health effects in animals and humans. While many of the toxic FRs have been eliminated and replaced by other FRs, existing products containing toxic or potentially toxic chemical FRs will remain in use for decades, and new products containing these and similar chemicals will permeate the environment. When such products reach the end of their useful life, proper disposal methods are needed to avoid health and ecological risks. To minimize continued human and environmental exposures to hazardous FR chemicals from discarded products, waste management technologies and processes must be improved. This review discusses a wide range of issues associated with all aspects of the use and responsible disposal of wastes containing FRs, and identifies basic and applied research needs in the areas of responsible collection, pretreatment, processing, and management of these wastes.

Determination of fluorine in organic compounds: Microcombustion method

USGS Publications Warehouse

Clark, H.S.

1951-01-01

A reliable and widely applicable means of determining fluorine in organic compounds has long been needed. Increased interest in this field of research in recent years has intensified the need. Fluorine in organic combinations may be determined by combustion at 900?? C. in a quartz tube with a platinum catalyst, followed by an acid-base titration of the combustion products. Certain necessary precautions and known limitations are discussed in some detail. Milligram samples suffice, and the accuracy of the method is about that usually associated with the other halogen determinations. Use of this method has facilitated the work upon organic fluorine compounds in this laboratory and it should prove to be equally valuable to others.

Transformation of methylparaben during water chlorination: Effects of bromide and dissolved organic matter on reaction kinetics and transformation pathways.

PubMed

Yoom, Hoonsik; Shin, Jaedon; Ra, Jiwoon; Son, Heejong; Ryu, Dongchoon; Kim, Changwon; Lee, Yunho

2018-09-01

The reaction kinetics, products, and pathways of methylparaben (MeP) during water chlorination with and without bromide (Br - ) were investigated to better understand the fate of parabens in chlorinated waters. During the chlorination of MeP-spiked waters without Br - , MeP was transformed into mono-Cl-MeP and di-Cl-MeP with apparent second-order rate constants (k app ) of 64M -1 s -1 and 243M -1 s -1 at pH7, respectively, while further chlorination of di-Cl-MeP was relatively slower (k app =1.3M -1 s -1 at pH7). With increasing Br - concentration, brominated MePs, such as mono-Br-MeP, Br-Cl-MeP, and di-Br-MeP, became major transformation products. The di-halogenated MePs (di-Cl-MeP, Br,Cl-MeP, and di-Br-MeP) showed relatively low reactivity to chlorine at pH7 (k app =1.3-4.6M -1 s -1 ) and bromine (k app =32-71M -1 s -1 ), which explains the observed high stability of di-halogenated MePs in chlorinated waters. With increasing pH from 7 to 8.5, the transformation of di-halogenated MePs was further slowed due to the decreasing reactivity of di-MePs to chlorine. The formation of the di-halogenated MePs and their further transformation become considerably faster at Br - concentrations higher than 0.5μM (40μg/L). Nonetheless, the accelerating effect of Br - diminishes in the presence of dissolved organic matter (DOM) extract (Suwannee River humic acid (SRHA)) due to a more rapid consumption of bromine by DOM than chlorine. The effect of Br - on the fate of MeP was less in the tested real water matrices, possibly due to a more rapid bromine consumption by the real water DOM compared to SRHA. A kinetic model was developed based on the determined species-specific second-order rate constants for chlorination/bromination of MeP and its chlorinated and brominated MePs and the transformation pathway information, which could reasonably simulate the transformation of MePs during the chlorination of water in the presence of Br - and selected DOM. Copyright © 2017 Elsevier B.V. All rights reserved.

40 CFR Table 1 to Subpart G of... - Process Vents-Coefficients for Total Resource Effectiveness for Existing Source Nonhalogenated...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Coefficients a b c d Nonhalogenated Flare 1.935 3.660×10−1 −7.687×10−3 −7.333×10−4 Thermal Incinerator 0... Standards for Organic Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry... 2.519 1.183×10−2 1.300×10−2 4.790×10−2 Halogenated Thermal Incinerator and Scrubber 3.995 5.200×10−2...

40 CFR Table 1 to Subpart G of... - Process Vents-Coefficients for Total Resource Effectiveness for Existing Source Nonhalogenated...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Coefficients a b c d Nonhalogenated Flare 1.935 3.660×10−1 −7.687×10−3 −7.333×10−4 Thermal Incinerator 0... Standards for Organic Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry... 2.519 1.183×10−2 1.300×10−2 4.790×10−2 Halogenated Thermal Incinerator and Scrubber 3.995 5.200×10−2...

40 CFR Table 1 to Subpart G of... - Process Vents-Coefficients for Total Resource Effectiveness for Existing Source Nonhalogenated...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Coefficients a b c d Nonhalogenated Flare 1.935 3.660×10−1 −7.687×10−3 −7.333×10−4 Thermal Incinerator 0... Standards for Organic Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry... 2.519 1.183×10−2 1.300×10−2 4.790×10−2 Halogenated Thermal Incinerator and Scrubber 3.995 5.200×10−2...

40 CFR Table 1 to Subpart G of... - Process Vents-Coefficients for Total Resource Effectiveness for Existing Source Nonhalogenated...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Coefficients a b c d Nonhalogenated Flare 1.935 3.660×10−1 −7.687×10−3 −7.333×10−4 Thermal Incinerator 0... Standards for Organic Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry... 2.519 1.183×10−2 1.300×10−2 4.790×10−2 Halogenated Thermal Incinerator and Scrubber 3.995 5.200×10−2...

Impact of enhanced ozone deposition and halogen chemistry on tropospheric ozone over the Northern Hemisphere

EPA Science Inventory

Fate of ozone in marine environments has been receiving increased attention due to the tightening of ambient air quality standards. The role of deposition and halogen chemistry is examined through incorporation of an enhanced ozone deposition algorithm and inclusion of halogen ch...

40 CFR 721.10145 - Modified reaction products of alkyl alcohol, halogenated alkane, substituted epoxide, and amino...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Modified reaction products of alkyl... Modified reaction products of alkyl alcohol, halogenated alkane, substituted epoxide, and amino compound... identified generically as modified reaction products of alkyl alcohol, halogenated alkane, substituted...

40 CFR 721.10145 - Modified reaction products of alkyl alcohol, halogenated alkane, substituted epoxide, and amino...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified reaction products of alkyl... Modified reaction products of alkyl alcohol, halogenated alkane, substituted epoxide, and amino compound... identified generically as modified reaction products of alkyl alcohol, halogenated alkane, substituted...

Halogenated arsenenes as Dirac materials

NASA Astrophysics Data System (ADS)

Tang, Wencheng; Sun, Minglei; Ren, Qingqiang; Wang, Sake; Yu, Jin

2016-07-01

Arsenene is the graphene-like arsenic nanosheet, which has been predicted very recently [S. Zhang, Z. Yan, Y. Li, Z. Chen, and H. Zeng, Angewandte Chemie, 127 (2015) 3155-3158]. Using first-principles calculations, we systematically investigate the structures and electronic properties of fully-halogenated arsenenes. Formation energy analysis reveals that all the fully-halogenated arsenenes except iodinated arsenene are energetically favorable and could be synthesized. We have revealed the presence of Dirac cone in fully-halogenated arsenene compounds. They may have great potential applications in next generation of high-performance devices.

α-Halogenated oxaphosphinanes: Synthesis, unexpected reactions and evaluation as inhibitors of cancer cell proliferation.

PubMed

Babouri, Rachida; Rolland, Marc; Sainte-Catherine, Odile; Kabouche, Zahia; Lecouvey, Marc; Bakalara, Norbert; Volle, Jean-Noël; Virieux, David; Pirat, Jean-Luc

2015-11-02

This paper describes the preparation and the biological evaluation of α-halogenated oxaphosphinanes. These halogen derivatives were synthetized from a short and stereoselective synthetic sequence starting by previously described hydroxy-precursors 1 and 2 with respectively a glucose and mannose-like configuration. The in vitro biological tests of these unnatural halogenated phosphinosugars, on several cell lines, highlighted, for some of them, their antiproliferative and anti migration and invasion properties at nanomolar concentration. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Density functional IR, Raman, and VCD spectra of halogen substituted β-lactams

NASA Astrophysics Data System (ADS)

Rode, Joanna E.; Dobrowolski, Jan Cz.

2003-06-01

Halogenoazetidinones are important as synthetic intermediates for preparation of halogen β-lactam (2-azetidinone) antibiotics and as building blocks for carbohydrates and amino acids. In this paper, we consider the influence of the halogen atom, substituted at the C4 position of the 2-azetidinone ring, on the geometry, IR, Raman, and vibrational circular dichroism spectra. The vibrational spectra were calculated for the chiral 4-( R)-X-2-azetidinone (X=F, Cl or Br) molecules at the B3PW91/aug-cc-pVTZ level. It was shown that the geometry of the molecules studied do not change much upon the change of the halogen atom. In case of the vibrational spectra, the position but even more the intensities depend strongly on the kind of halogen substituent.

Abnormal synergistic effects between Lewis acid-base interaction and halogen bond in F3B···NCX···NCM

NASA Astrophysics Data System (ADS)

Tang, Qingjie; Li, Qingzhong

2015-12-01

An abnormal synergistic effect was found between the Lewis acid-base interaction and halogen bond in triads F3B···NCX···NCM (X and M are halogen atoms), where the strong Lewis acid-base interaction between F3B and NCX has a larger enhancement than the weak halogen bond between NCX and NCM. This is in contrast with the traditional cooperative effect. It is interesting that the alkali-metal substituent as well as the heavier halogen atom play a more remarkable role in the enhancement of the interaction F3B···NCX than that of NCX···NCM, particularly, the alkali-metal substituent makes the abnormal synergistic effect be the traditional cooperative one.

Investigation of reactive halogens in the Arctic using a mobile instrumental laboratory

NASA Astrophysics Data System (ADS)

Custard, K.; Shepson, P. B.; Stephens, C. R.

2011-12-01

Custard, K kcustard@purdue.edu Chemistry Department, Purdue University, West Lafayette, IN, USA Shepson, P pshepson@purdue.edu Chemistry Department, Purdue University, West Lafayette, IN, USA Stephens, C thompscr@purdue.edu Chemistry Department, Purdue University, West Lafayette, IN, USA Investigation of the chemistry of reactive halogens in ice-covered regions is important because of its significant impact on atmospheric composition. Halogens in the Arctic react with ozone and gaseous elemental mercury to sometimes completely deplete them from the ambient atmosphere, at least during polar springtime. There is much uncertainty about the sources and concentrations of these atmospheric halogens in the Arctic, particularly with respect to chlorine. To gain a better understanding of them, we have developed a method to simultaneously measure the concentrations of BrOx and ClOx radicals using a flowtube method. The method involves reaction of the halogen atom with a halogenated alkene, to produce a multiply halogenated characteristic ketone product, which is then detected via GC/ECD. The system was deployed at Barrow, AK, using a mobile instrumental laboratory so that measurements could be made from multiple locations along the sea ice. In this paper we will discuss laboratory evaluation of the flowtube method, and present preliminary data from Barrow, AK, during the spring 2011 deployment.

Industrial waste pollution

NASA Technical Reports Server (NTRS)

Jensen, L. D.

1972-01-01

The characteristics and effects of industrial waste pollution in the Chesapeake Bay are discussed. The sources of inorganic and organic pollution entering the bay are described. The four types of pollutants are defined as: (1) inorganic chemical wastes, (2) naturally occurring organic wastes, (3) synthetic organic wastes (exotics) and (4) thermal effluents. The ecological behavior of industrial wastes in the surface waters is analyzed with respect to surface film phenomena, interfacial phenomena, and benthis phenomena

Tracing groundwater with low-level detections of halogenated VOCs in a fractured carbonate-rock aquifer, Leetown Science Center, West Virginia, USA

USGS Publications Warehouse

Plummer, Niel; Sibrell, Philip L.; Casile, Gerolamo C.; Busenberg, Eurybiades; Hunt, Andrew G.; Schlosser, Peter

2013-01-01

Measurements of low-level concentrations of halogenated volatile organic compounds (VOCs) and estimates of groundwater age interpreted from 3H/3He and SF6 data have led to an improved understanding of groundwater flow, water sources, and transit times in a karstic, fractured, carbonate-rock aquifer at the Leetown Science Center (LSC), West Virginia. The sum of the concentrations of a set of 16 predominant halogenated VOCs (TDVOC) determined by gas chromatography with electron-capture detector (GC–ECD) exceeded that possible for air–water equilibrium in 34 of the 47 samples (median TDVOC of 24,800 pg kg−1), indicating that nearly all the water sampled in the vicinity of the LSC has been affected by addition of halogenated VOCs from non-atmospheric source(s). Leakage from a landfill that was closed and sealed nearly 20 a prior to sampling was recognized and traced to areas east of the LSC using low-level detection of tetrachloroethene (PCE), methyl chloride (MeCl), methyl chloroform (MC), dichlorodifluoromethane (CFC-12), and cis-1,2-dichloroethene (cis-1,2-DCE). Chloroform (CHLF) was the predominant VOC in water from domestic wells surrounding the LSC, and was elevated in groundwater in and near the Fish Health Laboratory at the LSC, where a leak of chlorinated water occurred prior to 2006. The low-level concentrations of halogenated VOCs did not exceed human or aquatic-life health criteria, and were useful in providing an awareness of the intrinsic susceptibility of the fractured karstic groundwater system at the LSC to non-atmospheric anthropogenic inputs. The 3H/3He groundwater ages of spring discharge from the carbonate rocks showed transient behavior, with ages averaging about 2 a in 2004 following a wet climatic period (2003–2004), and ages in the range of 4–7 a in periods of more average precipitation (2008–2009). The SF6 and CFC-12 data indicate older water (model ages of 10s of years or more) in the low-permeability shale of the Martinsburg Formation located to the west of the LSC. A two-a record of specific conductance, water temperature, and discharge recorded at 30-min intervals demonstrated an approximately 3-month lag in discharge at Gray Spring. The low groundwater ages of waters from the carbonate rocks support rapid advective transport of contaminants from the LSC vicinity, yet the nearly ubiquitous occurrence of low-level concentrations of halogenated VOCs at the LSC suggests the presence of long-term persistent sources, such as seepage from the closed and sealed landfill, infiltration of VOCs that may persist locally in the epikarst, exchange with low-permeability zones in fractured rock, and upward leakage of older water that may contain elevated concentrations of halogenated VOCs from earlier land use activities.

Alternative Fuels Data Center: quasar energy group Turns Organic Waste into

Science.gov Websites

Renewable Energy in Ohio quasar energy group Turns Organic Waste into Renewable Energy in Ohio to someone by E-mail Share Alternative Fuels Data Center: quasar energy group Turns Organic Waste group Turns Organic Waste into Renewable Energy in Ohio on Twitter Bookmark Alternative Fuels Data

Hydridomethyl iridium complex

DOEpatents

Bergman, Robert G.; Buchanan, J. Michael; Stryker, Jeffrey M.; Wax, Michael J.

1989-01-01

A process for functionalizing methane comprising: (a) reacting methane with a hydridoalkyl metal complex of the formula: CpIr[P(R.sub.1).sub.3 ]H(R.sub.2) wherein Cp represents a cyclopentadienyl or alkylcyclopentadienyl radical having from 1 to 5 carbon atoms; Ir represents an iridium atom; P represents a phosphorus atom; R.sub.1 represents an alkyl group; R.sub.2 represents an alkyl group having at least two carbon atoms; and H represents a hydrogen atom, in the presence of a liquid alkane R.sub.3 H having at least three carbon atoms to form a hydridomethyl complex of the formula: CpIr[P(R.sub.1).sub.3 ]HMe where Me represents a methyl radical. (b) reacting said hydridomethyl complex with an organic halogenating agent such as a tetrahalomethane or a haloform of the formulas: CX'X"X'"X"" or CHX'X"X'"; wherein X', X", X"', and X"" represent halogens selected from bromine, iodine and chlorine, to halomethyl complex of step (a) having the formula: CpIr[P(R.sub.1).sub.3 ]MeX: (c) reacting said halomethyl complex with a mercuric halide of the formula HgX.sub.2 to form a methyl mercuric halide of the formula HgMeX; and (d) reacting said methyl mercuric halide with a molecular halogen of the formula X.sub.2 to form methyl halide.

Organic Separation Test Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.

2014-09-22

Separable organics have been defined as “those organic compounds of very limited solubility in the bulk waste and that can form a separate liquid phase or layer” (Smalley and Nguyen 2013), and result from three main solvent extraction processes: U Plant Uranium Recovery Process, B Plant Waste Fractionation Process, and Plutonium Uranium Extraction (PUREX) Process. The primary organic solvents associated with tank solids are TBP, D2EHPA, and NPH. There is concern that, while this organic material is bound to the sludge particles as it is stored in the tanks, waste feed delivery activities, specifically transfer pump and mixer pump operations,more » could cause the organics to form a separated layer in the tank farms feed tank. Therefore, Washington River Protection Solutions (WRPS) is experimentally evaluating the potential of organic solvents separating from the tank solids (sludge) during waste feed delivery activities, specifically the waste mixing and transfer processes. Given the Hanford Tank Waste Treatment and Immobilization Plant (WTP) waste acceptance criteria per the Waste Feed Acceptance Criteria document (24590-WTP-RPT-MGT-11-014) that there is to be “no visible layer” of separable organics in the waste feed, this would result in the batch being unacceptable to transfer to WTP. This study is of particular importance to WRPS because of these WTP requirements.« less

Kinetics and mechanisms of some atomic oxygen reactions

NASA Technical Reports Server (NTRS)

Cvetanovic, R. J.

1987-01-01

Mechanisms and kinetics of some reactions of the ground state of oxygen atoms, O(3P), are briefly summarized. Attention is given to reactions of oxygen atoms with several different types of organic and inorganic compounds such as alkanes, alkenes, alkynes, aromatics, and some oxygen, nitrogen, halogen and sulfur derivatives of these compounds. References to some recent compilations and critical evaluations of reaction rate constants are given.

Characteristics of a newly isolated fungus Geotrichum candidum Dec 1 with broad degradation spectrum of xenobiotic compounds.

PubMed

Shoda, M

2003-01-01

A newly isolated fungus, Geotrichum candidum Dec 1 (abbreviated as Dec 1), was found to have the ability to degrade many xenobiotic compounds such as synthetic dyes, food coloring agents, molasses, organic halogens, lignin and kraft pulp effluents. The broad spectrum of the degradation of these compounds are associated mainly with peroxidases produced by the fungus.

Identifying and Determining Halocarbons in Water Using Headspace Gas Chromatography.

DTIC Science & Technology

1981-10-01

chromatography Halogenated hydrocarbons , / Wastewater 26. T -ACT C’Cth.I .- ,,ee .- ,ncee, ,Id ntify y block number) --/,*Since the discovery that...USING HEADSPACE GAS CHROMATOGRAPHY Daniel C. Leggett INTRODUCTION Chlorination is a well-established method of disinfecting water for drinking and of... disinfecting municipal wastewater prior to disposal. The recent discovery that persistent chloro-organic molecules are formed in this processi 5 has

Singlet oxygen production by combining erythrosine and halogen light for photodynamic inactivation of Streptococcus mutans.

PubMed

Fracalossi, Camila; Nagata, Juliana Yuri; Pellosi, Diogo Silva; Terada, Raquel Sano Suga; Hioka, Noboru; Baesso, Mauro Luciano; Sato, Francielle; Rosalen, Pedro Luiz; Caetano, Wilker; Fujimaki, Mitsue

2016-09-01

Photodynamic inactivation of microorganisms is based on a photosensitizing substance which, in the presence of light and molecular oxygen, produces singlet oxygen, a toxic agent to microorganisms and tumor cells. This study aimed to evaluate singlet oxygen quantum yield of erythrosine solutions illuminated with a halogen light source in comparison to a LED array (control), and the photodynamic effect of erythrosine dye in association with the halogen light source on Streptococcus mutans. Singlet oxygen quantum yield of erythrosine solutions was quantified using uric acid as a chemical-probe in an aqueous solution. The in vitro effect of the photodynamic antimicrobial activity of erythrosine in association with the halogen photopolimerizing light on Streptococcus mutans (UA 159) was assessed during one minute. Bacterial cultures treated with erythrosine alone served as negative control. Singlet oxygen with 24% and 2.8% degradation of uric acid in one minute and a quantum yield of 0.59 and 0.63 was obtained for the erythrosine samples illuminated with the halogen light and the LED array, respectively. The bacterial cultures with erythrosine illuminated with the halogen light presented a decreased number of CFU mL(-1) in comparison with the negative control, with minimal inhibitory concentrations between 0.312 and 0.156mgmL(-1). The photodynamic response of erythrosine induced by the halogen light was capable of killing S. mutans. Clinical trials should be conducted to better ascertain the use of erythrosine in association with halogen light source for the treatment of dental caries. Copyright © 2016 Elsevier B.V. All rights reserved.

Role of halogen and hydrogen bonds for stabilization of antithyroid drugs with hypohalous acids (HOX, X = I, Br, and Cl) adducts

NASA Astrophysics Data System (ADS)

El-Sheshtawy, Hamdy S.; El-Mehasseb, Ibrahim

2017-11-01

The mechanism for the inhibition of thyroid hormones by the thioamide-like antithyroid drug is a key process in the thyroid gland function. Therefore, in this study theoretical investigation of the molecular interaction between two antithyroid drugs, namely methimazol (MMI) and thiazoline-2-thione (T2T), with the hypohalous acids (HOX, X = I, Br, and Cl), which act as heme-linked halogenated species to tyrosine residue was discussed. The calculations were performed by M06-2X and MP2 using aug-cc-pVDZ level of theory. In addition, wB97xd/6-31G* level of theory was used in order to account for the dispersion forces. The results show the possible formation of three adducts, which is stabilized by halogen bond (I), both halogen and hydrogen bonds (II), two hydrogen bonds (III). The binding energies of the complexes reveals stabilization in the order III > II > I. The binding energies of the complexes was increased with increasing the electron affinity and polarizability of halogen atom, the dipole moment of the complexes (I and II), the electrostatic potential on halogen atom (Vmax:i.e σ-hole), and the charge-transfer process through the halogen bond in I. On the other hand, the binding energies of the complexes decreased with increasing the halogen atom electronegativity and the dipole moment of complex III. Natural bond orbital (NBO) analysis was used to investigate the molecular orbital interactions and the charge transfer process upon complexation.

79/81Br nuclear quadrupole resonance spectroscopic characterization of halogen bonds in supramolecular assemblies† †Electronic supplementary information (ESI) available: 13C SSNMR spectra, powder X-ray diffractograms. See DOI: 10.1039/c8sc01094c

PubMed Central

Cerreia Vioglio, P.; Szell, P. M. J.; Chierotti, M. R.; Gobetto, R.

2018-01-01

Despite the applicability of solid-state NMR to study the halogen bond, the direct NMR detection of 79/81Br covalently bonded to carbon remains impractical due to extremely large spectral widths, even at ultra-high magnetic fields. In contrast, nuclear quadrupole resonance (NQR) offers comparatively sharp resonances. Here, we demonstrate the abilities of 79/81Br NQR to characterize the electronic changes in the C–Br···N halogen bonding motifs found in supramolecular assemblies constructed from 1,4-dibromotetrafluorobenzene and nitrogen-containing heterocycles. An increase in the bromine quadrupolar coupling constant is observed, which correlates linearly with the halogen bond distance (dBr···N). Notably, 79/81Br NQR is able to distinguish between two symmetry-independent halogen bonds in the same crystal structure. This approach offers a rapid and reliable indication for the occurrence of a halogen bond, with experimental times limited only by the observation of 79/81Br NQR resonances. PMID:29899948

Ecotoxicological risk assessment of hospital wastewater: a proposed framework for raw effluents discharging into urban sewer network.

PubMed

Emmanuel, E; Perrodin, Y; Keck, G; Blanchard, J-M; Vermande, P

2005-01-14

In hospitals a large variety of substances are in use for medical purposes such as diagnostics and research. After application, diagnostic agents, disinfectants and excreted non-metabolized pharmaceuticals by patients, reach the wastewater. This form of elimination may generate risks for aquatic organisms. The aim of this study was to present: (i) the steps of an ecological risk assessment and management framework related to hospital effluents evacuating into wastewater treatment plant (WWTP) without preliminary treatment; and (ii) the results of its application on wastewater from an infectious and tropical diseases department of a hospital of a large city in southeastern France. The characterization of effects has been made under two assumptions, which were related to: (a) the effects of hospital wastewater on biological treatment process of WWTP, particularly on the community of organisms in charge of the biological decomposition of the organic matter; (b) the effects on aquatic organisms. COD and BOD5 have been measured for studying global organic pollution. Assessment of halogenated organic compounds was made using halogenated organic compounds absorbable on activated carbon (AOX) concentrations. Heavy metals (arsenic, cadmium, chrome, copper, mercury, nickel, lead and zinc) were measured. Low most probable number (MPP) for faecal coliforms has been considered as an indirect detection of antibiotics and disinfectants presence. For toxicity assessment, bioluminescence assay using Vibrio fischeri photobacteria, 72-h EC50 algae growth Pseudokirchneriella subcapitata and 24-h EC50 on Daphnia magna were used. The scenario allows to a semi-quantitative risk characterization. It needs to be improved on some aspects, particularly those linked to: long term toxicity assessment on target organisms (bioaccumulation of pollutants, genotoxicity, etc.); ecotoxicological interactions between pharmaceuticals, disinfectants used both in diagnostics and in cleaning of surfaces, and detergents used in cleaning of surfaces; the interactions into the sewage network, between the hospital effluents and the aquatic ecosystem.

Assessing the impacts of changes in treatment technology on energy and greenhouse gas balances for organic waste and wastewater treatment using historical data.

PubMed

Poulsen, Tjalfe G; Hansen, Jens Aage

2009-11-01

Historical data on organic waste and wastewater treatment during the period of 1970-2020 were used to assess the impact of treatment on energy and greenhouse gas (GHG) balances. The assessment included the waste fractions: Sewage sludge, food waste, yard waste and other organic waste (paper, plastic, etc.). Data were collected from Aalborg, a municipality located in Northern Denmark. During the period from 1970-2005, Aalborg Municipality has changed its waste treatment strategy from landfilling of all wastes toward composting of yard waste and incineration with combined heat and power production from the remaining organic municipal waste. Wastewater treatment has changed from direct discharge of untreated wastewater to full organic matter and nutrient (N, P) removal combined with anaerobic digestion of the sludge for biogas production with power and heat generation. These changes in treatment technology have resulted in the waste and wastewater treatment systems in Aalborg progressing from being net consumers of energy and net emitters of GHG, to becoming net producers of energy and net savers of GHG emissions (due to substitution of fossil fuels elsewhere). If it is assumed that the organic waste quantity and composition is the same in 1970 and 2005, the technology change over this time period has resulted in a progression from a net annual GHG emission of 200 kg CO( 2)-eq. capita(-1) in 1970 to a net saving of 170 kg CO(2)-eq. capita(-1) in 2005 for management of urban organic wastes.

Effects of biochars produced from solid organic municipal waste on soil quality parameters

USDA-ARS?s Scientific Manuscript database

New, value-added uses for solid organic waste are needed for environmental and economic sustainability. Fortunately, value-added biochars can be produced from mixed organic solid waste, thereby addressing solid waste management issues, and enabling long-term carbon sequestration. We hypothesize that...

Comparison of solid-phase and eluate assays to gauge the ecotoxicological risk of organic wastes on soil organisms.

PubMed

Domene, Xavier; Alcañiz, Josep M; Andrés, Pilar

2008-02-01

Development of methodologies to assess the safety of reusing polluted organic wastes in soil is a priority in Europe. In this study, and coupled with chemical analysis, seven organic wastes were subjected to different aquatic and soil bioassays. Tests were carried out with solid-phase waste and three different waste eluates (water, methanol, and dichloromethane). Solid-phase assays were indicated as the most suitable for waste testing not only in terms of relevance for real situations, but also because toxicity in eluates was generally not representative of the chronic effects in solid-phase. No general correlations were found between toxicity and waste pollutant burden, neither in solid-phase nor in eluate assays, showing the inability of chemical methods to predict the ecotoxicological risks of wastes. On the contrary, several physicochemical parameters reflecting the degree of low organic matter stability in wastes were the main contributors to the acute toxicity seen in collembolans and daphnids.

Degree of conversion of two lingual retainer adhesives cured with different light sources.

PubMed

Usümez, Serdar; Büyükyilmaz, Tamer; Karaman, Ali Ihya; Gündüz, Beniz

2005-04-01

The aim of this study was to evaluate the degree of conversion (DC) of two lingual retainer adhesives, Transbond Lingual Retainer (TLR) and Light Cure Retainer (LCR), cured with a fast halogen light, a plasma arc light and a light-emitting diode (LED) at various curing times. A conventional halogen light served as the control. One hundred adhesive samples (five per group) were cured for 5, 10 or 15 seconds with an Optilux 501 (fast halogen light), for 3, 6 or 9 seconds with a Power Pac (plasma arc light), or for 10, 20 or 40 seconds with an Elipar Freelight (LED). Samples cured for 40 seconds with the conventional halogen lamp were used as the controls. Absorbance peaks were recorded using Fourier transform infrared (FT-IR) spectroscopy. DC values were calculated. Data were analysed using Kruskal-Wallis and Mann-Whitney U-tests. For the TLR, the highest DC values were achieved in 6 and 9 seconds with the plasma arc light. Curing with the fast halogen light for 15 seconds and with the LED for 40 seconds produced statistically similar DC values, but these were lower than those with the plasma arc light. All of these light exposures yielded a statistically significantly higher DC than 40 seconds of conventional halogen light curing. The highest DC value for the LCR was achieved in 15 seconds with the fast halogen light, then the plasma arc light curing for 6 seconds. These two combinations produced a statistically significantly higher DC when compared with the 40 seconds of conventional halogen light curing. The lowest DC for the LCR was achieved with 10 seconds of LED curing. The overall DC of the LCR was significantly higher than that of the TLR. The results suggest that a similar or higher DC than the control values could be achieved in 6-9 seconds by plasma arc curing, in 10-15 seconds by fast halogen curing or in 20 seconds by LED curing.

Halogens in chondritic meteorites and terrestrial accretion

NASA Astrophysics Data System (ADS)

Clay, Patricia L.; Burgess, Ray; Busemann, Henner; Ruzié-Hamilton, Lorraine; Joachim, Bastian; Day, James M. D.; Ballentine, Christopher J.

2017-11-01

Volatile element delivery and retention played a fundamental part in Earth’s formation and subsequent chemical differentiation. The heavy halogens—chlorine (Cl), bromine (Br) and iodine (I)—are key tracers of accretionary processes owing to their high volatility and incompatibility, but have low abundances in most geological and planetary materials. However, noble gas proxy isotopes produced during neutron irradiation provide a high-sensitivity tool for the determination of heavy halogen abundances. Using such isotopes, here we show that Cl, Br and I abundances in carbonaceous, enstatite, Rumuruti and primitive ordinary chondrites are about 6 times, 9 times and 15-37 times lower, respectively, than previously reported and usually accepted estimates. This is independent of the oxidation state or petrological type of the chondrites. The ratios Br/Cl and I/Cl in all studied chondrites show a limited range, indistinguishable from bulk silicate Earth estimates. Our results demonstrate that the halogen depletion of bulk silicate Earth relative to primitive meteorites is consistent with the depletion of lithophile elements of similar volatility. These results for carbonaceous chondrites reveal that late accretion, constrained to a maximum of 0.5 ± 0.2 per cent of Earth’s silicate mass, cannot solely account for present-day terrestrial halogen inventories. It is estimated that 80-90 per cent of heavy halogens are concentrated in Earth’s surface reservoirs and have not undergone the extreme early loss observed in atmosphere-forming elements. Therefore, in addition to late-stage terrestrial accretion of halogens and mantle degassing, which has removed less than half of Earth’s dissolved mantle gases, the efficient extraction of halogen-rich fluids from the solid Earth during the earliest stages of terrestrial differentiation is also required to explain the presence of these heavy halogens at the surface. The hydropilic nature of halogens, whereby they track with water, supports this requirement, and is consistent with volatile-rich or water-rich late-stage terrestrial accretion.

Modelling of Two-Stage Methane Digestion With Pretreatment of Biomass

NASA Astrophysics Data System (ADS)

Dychko, A.; Remez, N.; Opolinskyi, I.; Kraychuk, S.; Ostapchuk, N.; Yevtieieva, L.

2018-04-01

Systems of anaerobic digestion should be used for processing of organic waste. Managing the process of anaerobic recycling of organic waste requires reliable predicting of biogas production. Development of mathematical model of process of organic waste digestion allows determining the rate of biogas output at the two-stage process of anaerobic digestion considering the first stage. Verification of Konto's model, based on the studied anaerobic processing of organic waste, is implemented. The dependencies of biogas output and its rate from time are set and may be used to predict the process of anaerobic processing of organic waste.

40 CFR 265.1084 - Waste determination procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... to determine the organic biodegradation efficiency (Rbio) for a treated hazardous waste. (i) The... Where: Rbio = Organic biodegradation efficiency, percent. Fbio = Fraction of organic biodegraded as... to determine the actual organic mass biodegradation rate (MRbio) for a treated hazardous waste. (i...

C-I···π Halogen Bonding Driven Supramolecular Helix of Bilateral N-Amidothioureas Bearing β-Turns.

PubMed

Cao, Jinlian; Yan, Xiaosheng; He, Wenbin; Li, Xiaorui; Li, Zhao; Mo, Yirong; Liu, Maili; Jiang, Yun-Bao

2017-05-17

We report the first example of C-I···π halogen bonding driven supramolecular helix in highly dilute solution of micromolar concentration, using alanine based bilateral I-substituted N-amidothioureas that contain helical fragments, the β-turn structures. The halogen bonding interactions afford head-to-tail linkages that help to propagate the helicity of the helical fragments. In support of this action of the halogen bonding, chiral amplification was observed in the supramolecular helix formed in acetonitrile solution. The present finding provides alternative tools in the design of self-assembling macromolecules.

Aromatic fluorine compounds. XI. Replacement of chlorine by fluorine in halopyridines

USGS Publications Warehouse

Finger, G.C.; Starr, L.D.; Dickerson, D.R.; Gutowsky, H.S.; Hamer, J.

1963-01-01

The ??-halogenated pyridines react with potassium fluoride in various solvents to give replacement of the ??-halogen by fluorine. A 50% yield of 2-fluoropyridine was obtained from 2-chloropyridine by heating with potassium fluoride in dimethyl sulfone or tetramethylene sulfone for twenty-one days; 2-bromopyridine gave a similar yield with a heating period of only seven days. The ??-halogens of the polyhalopyridines undergo the exchange reaction more readily than do the halogens of the ??-monohalopyridines. The proposed structures of the fluoropyridines are supported by alternate syntheses and by n.m.r. studies.

Halogen Bonding: A Powerful Tool for Modulation of Peptide Conformation

PubMed Central

2017-01-01

Halogen bonding is a weak chemical force that has so far mostly found applications in crystal engineering. Despite its potential for use in drug discovery, as a new molecular tool in the direction of molecular recognition events, it has rarely been assessed in biopolymers. Motivated by this fact, we have developed a peptide model system that permits the quantitative evaluation of weak forces in a biologically relevant proteinlike environment and have applied it for the assessment of a halogen bond formed between two amino acid side chains. The influence of a single weak force is measured by detection of the extent to which it modulates the conformation of a cooperatively folding system. We have optimized the amino acid sequence of the model peptide on analogues with a hydrogen bond-forming site as a model for the intramolecular halogen bond to be studied, demonstrating the ability of the technique to provide information about any type of weak secondary interaction. A combined solution nuclear magnetic resonance spectroscopic and computational investigation demonstrates that an interstrand halogen bond is capable of conformational stabilization of a β-hairpin foldamer comparable to an analogous hydrogen bond. This is the first report of incorporation of a conformation-stabilizing halogen bond into a peptide/protein system, and the first quantification of a chlorine-centered halogen bond in a biologically relevant system in solution. PMID:28581720

The influence of ocean halogen and sulfur emissions in the air quality of a coastal megacity: The case of Los Angeles

EPA Science Inventory

The oceans are the main source of natural halogen and sulfur compounds, which have a significant influence on the oxidizing capacity of the marine atmosphere; however, their impact on the air quality of coastal cities is currently unknown. We explore the effect of marine halogens...

Halogen-free benzoxazine based curable compositions for high TG applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tietze, Roger; Nguyen, Yen-Loan

The present invention provides a halogen-free curable composition including a benzoxazine monomer, at least one epoxy resin, a catalyst, a toughening agent and a solvent. The halogen-free curable composition is especially suited for use in automobile and aerospace applications since the composition, upon curing, produces a composite having a high glass transition temperature.

Halogen free benzoxazine based curable compositions for high T.sub.g applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tietze, Roger; Nguyen, Yen-Loan

A method for forming a halogen-free curable composition containing a benzoxazine monomer, at least one epoxy resin, a catalyst, a toughening agent and a solvent. The halogen-free curable composition is especially suited for use in automobile and aerospace applications since the composition, upon curing, produces a composite having a high glass transition temperature.

Revisiting the elemental composition and the calorific value of the organic fraction of municipal solid wastes.

PubMed

Komilis, Dimitrios; Evangelou, Alexandros; Giannakis, Georgios; Lymperis, Constantinos

2012-03-01

In this work, the elemental content (C, N, H, S, O), the organic matter content and the calorific value of various organic components that are commonly found in the municipal solid waste stream were measured. The objective of this work was to develop an empirical equation to describe the calorific value of the organic fraction of municipal solid waste as a function of its elemental composition. The MSW components were grouped into paper wastes, food wastes, yard wastes and plastics. Sample sizes ranged from 0.2 to 0.5 kg. In addition to the above individual components, commingled municipal solid wastes were sampled from a bio-drying facility located in Crete (sample sizes ranged from 8 to 15 kg) and were analyzed for the same parameters. Based on the results of this work, an improved empirical model was developed that revealed that carbon, hydrogen and oxygen were the only statistically significant predictors of calorific value. Total organic carbon was statistically similar to total carbon for most materials in this work. The carbon to organic matter ratio of 26 municipal solid waste substrates and of 18 organic composts varied from 0.40 to 0.99. An approximate chemical empirical formula calculated for the organic fraction of commingled municipal solid wastes was C(32)NH(55)O(16). Copyright © 2011 Elsevier Ltd. All rights reserved.

Influence of Selected Organic Micropollutants on Organisms

NASA Astrophysics Data System (ADS)

Włodarczyk-Makuła, Maria

2017-03-01

This article describes the toxicity of organic micropollutants on tested microorganisms. Itis a current issue because organic micropollutants are identified in all elements of environmental (surface water, ground water, soils) and in food products. The organic micropollutants include: polychlorinated dibenzodioxyns PCDD, polychlorinated dibenzofurans PCDF, polychlorinated biphenyls PCB, polycyclic aromatic hydrocarbons PAH, halogenated compounds and by-products of water treatment. Some organic compounds cause hazard for health and human life due to their estrogenic biological activity, carcinogenic, mutagenic or teratogenic activity. The influence on organisms indicators of these compounds based on literature data were presented. The level of TEQ (toxic equivalency) in response to organic chlorine derivatives (PCDDs, PCDF, PCBs) is usually determined by toxic equivalency factor (TEF). The International Agency for Research on Cancer classifies organic micropollutants as carcinogenic to humans (Group 1), possibly carcinogenic (Group 2A) or probably carcinogenic to humans (Group 2B).

Halogens in normal- and enriched-basalts from Central Indian Ridge (18-20°S): Testing the E-MORB subduction origin hypothesis

NASA Astrophysics Data System (ADS)

Ruzie, L.; Burgess, R.; Hilton, D. R.; Ballentine, C. J.

2012-12-01

Basalts emitted along oceanic ridges have often been subdivided into two categories: the Normal-MORB and the Enriched-MORB, anomalously enriched in highly incompatible elements. Donnelly et al. (2004) proposed that the formation of enriched sources is related to two stages of melting. The first one occurs in subduction zones where the mantle wedge is enriched by the addition of low-degree melts of subducted slab. The second stage of melting occurs beneath ocean ridges. Because of their incompatibility, relatively high concentrations and distinct elemental compositions in surface reservoirs, the heavy halogens (Cl, Br, I) are good tracers to detect the slab contribution in E-MORB sources. However, the halogen systematics in mantle reservoirs remains poorly constrained mainly because of their very low abundance in materials of interest. An innovative halogen analytical technique, developed at the University of Manchester, involving neutron irradiation of samples to convert halogens to noble gases provides detection limits unmatched by any other technique studies [Johnson et al. 2000]. For the first time Cl, Br and I can now be determined in appropriate samples. We focus on the content of halogens in the glassy margins of basalts erupted along the CIR from 18-20°S and the off-axis Gasitao Ridge. Our set of samples contains both N- and E-MORB and is fully described in terms of major and trace elements, as well as 3He/4He ratios and water concentrations [Murton et al., 2005; Nauret et al., 2006; Füri et al., 2011; Barry et al., in prep.]. The halogen concentration range is between 10 and 140 ppm for Cl, 30 and 500 ppb for Br and 0.8 and 10 ppb for I. The higher concentrations are found in E-MORB samples from the northern part of ridge axis. Comparing our data with previous halogen studies, our sample suites fall within the range of N-MORB from East Pacific Ridge (EPR) and Mid-Atlantic Ridge (MAR) [Jambon et al. 1995; Deruelle et al. 1992] and in the lower range of E-MORB from Macquarie Island [Kendrick et al., 2012]. The concentrations are not related to superficial processes. The on-axis samples display a relatively restricted range (6.9-8.6wt%) of MgO contents, suggesting no control of the crystallisation processes. The basalts were erupted between 3900-2000 m bsl, so no appreciable degassing of halogens would be expected. The strong correlation, which exists between the halogens and other incompatible elements (e.g., Rb, La), also rules out seawater assimilation. Therefore, concentrations and elemental ratios can be directly linked to melting and source features. Estimates of halogens abundances in the depleted-mantle source are 4 ppm Cl, 14 ppb Br and 0.3 ppb I. These low abundances, which are in agreement with values derived for sub-continental mantle from coated diamonds [Burgess et al., 2002], suggest that, like noble gases, the upper mantle is degassed of its halogens. Critically, the halogen elemental ratios show no significant variations along the axial ridge and off-axis ridge or between N-MORB and E-MORB: Br/Cl=0.00147±0.00014, I/Cl=0.000021±0.000005; I/Br=0.0142±0.0036. These ratios are similar to E-MORB from Macquarie Island [Kendrick et al., 2012]. This observation is thus not consistent with subduction as a source of halogen enrichment in E-MORB.

The halogen bond: Nature and applications

NASA Astrophysics Data System (ADS)

Costa, Paulo J.

2017-10-01

The halogen bond, corresponding to an attractive interaction between an electrophilic region in a halogen (X) and a nucleophile (B) yielding a R-X⋯B contact, found applications in many fields such as supramolecular chemistry, crystal engineering, medicinal chemistry, and chemical biology. Their large range of applications also led to an increased interest in their study using computational methods aiming not only at understanding the phenomena at a fundamental level, but also to help in the interpretation of results and guide the experimental work. Herein, a succinct overview of the recent theoretical and experimental developments is given starting by discussing the nature of the halogen bond and the latest theoretical insights on this topic. Then, the effects of the surrounding environment on halogen bonds are presented followed by a presentation of the available method benchmarks. Finally, recent experimental applications where the contribution of computational chemistry was fundamental are discussed, thus highlighting the synergy between the lab and modeling techniques.

National markets for organic waste-derived fertilizers and soil amendments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Logan, T.J.; Pierzynski, G.M.; Pepperman, R.E.

1995-12-31

The last decade has seen enormous growth in the U.S. in the recycling of organic waste materials like sewage sludge, manures, yard waste, solid waste and various industrial wastes. This has been prompted by real or perceived shortages of landfill capacity, state and federal regulations favoring beneficial use of organic wastes, and public support for recycling. Use of fertilizers and soil amendments derived from these wastes has been stimulated by favorable supply-side economics, a shift to organic/sustainable agriculture, and water quality concerns that favor slow-release nutrient sources. This paper summarizes the properties and beneficial use attributes of the various wastesmore » and their derived products, markets for these materials, and constraints/strategies for market penetration.« less

A review on organic waste to energy systems in India.

PubMed

Dhar, Hiya; Kumar, Sunil; Kumar, Rakesh

2017-12-01

Waste generation is increasing day-by-day with the growth of population which directly affects the environment and economy. Organic municipal solid waste (MSW) and agriculture sectors contribute towards maximum waste generation in India. Thus, management of organic waste is very much essential with the increasing demand for energy. The present paper mainly focusses on reviewing waste to energy (WtE) potentials, its technologies, and the associated challenges. Different substrates are utilized through various technological options in India. Organic waste has good potential to attain sustainable energy yields with and without affecting the environment. A realistic scenario of WtE technologies and their challenges in line with the existing Indian condition is presented in this paper. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantitative analysis of impact of awareness-raising activities on organic solid waste separation behaviour in Balikpapan City, Indonesia.

PubMed

Murase, Noriaki; Murayama, Takehiko; Nishikizawa, Shigeo; Sato, Yuriko

2017-10-01

Many cities in Indonesia are under pressure to reduce solid waste and dispose of it properly. In response to this pressure, the Japan International Cooperation Agency and the Indonesian Government have implemented a solid waste separation and collection project to reduce solid waste in the target area (810 households) of Balikpapan City. We used a cluster randomised controlled trial method to measure the impact of awareness-raising activities that were introduced by the project on residents' organic solid waste separation behaviour. The level of properly separated organic solid waste increased by 6.0% in areas that conducted awareness-raising activities. Meanwhile, the level decreased by 3.6% in areas that did not conduct similar activities. Therefore, in relative comparison, awareness-raising increased the level by 9.6%. A comparison among small communities in the target area confirmed that awareness-raising activities had a significant impact on organic solid waste separation. High frequencies of monitoring at waste stations and door-to-door visits by community members had a positive impact on organic solid waste separation. A correlation between the proximity of environmental volunteers' houses to waste stations and a high level of separation was also confirmed. The awareness-raising activities introduced by the project led to a significant increase in the separation of organic solid waste.

Numerical simulation of organic waste aerobic biodegradation: a new way to correlate respiration kinetics and organic matter fractionation.

PubMed

Denes, Jeremy; Tremier, Anne; Menasseri-Aubry, Safya; Walter, Christian; Gratteau, Laurette; Barrington, Suzelle

2015-02-01

Composting wastes permits the reuse of organic matter (OM) as agricultural amendments. The fate of OM during composting and the subsequent degradation of composts in soils largely depend on waste OM quality. The proposed study aimed at developing a model to predict the evolution in organic matter quality during the aerobic degradation of organic waste, based on the quantification of the various OM fractions contained in the wastes. The model was calibrated from data gathered during the monitoring of four organic wastes (two non-treated wastes and their digestates) exposed to respirometric tests. The model was successfully fitted for all four wastes and permitted to predict respiration kinetics, expressed as CO2 production rates, and the evolution of OM fractions. The calibrated model demonstrated that hydrolysis rates of OM fractions were similar for all four wastes whereas the parameters related to microbial activity (eg. growth and death rates) were specific to each substrate. These later parameters have been estimated by calibration on respirometric data, thus demonstrating that coupling analyses of OM fractions in initial wastes and respirometric tests permit the simulation of the biodegradation of various type of waste. The biodegradation model presented in this paper could thereafter be integrated in a composting model by implementing mass and heat balance equations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Emissions of Bromine and Iodine from the Marine Environment in New Zealand

NASA Astrophysics Data System (ADS)

Martinez-Aviles, M.; Kreher, K.; Johnston, P. V.; Hay, T.; Thomas, A.; Schofield, R.

2009-12-01

As noted in the WMO/UNEP Scientific Assessment of Ozone Depletion: 2006, halogenated very short-lived substances (VSLS) contribute to the atmospheric budget of halogens and thereby lead to substantial decreases in ozone and increases in surface UV radiation in the tropics and mid-latitudes. Halogenated VSLS are primarily of natural origin; oceanic emissions constitute the largest source providing 90-95% of the total global flux to the atmosphere. Macro algae in the ocean appear to be an important source of polyhalogenated VSLS. Oxidation of halogenated VSLS in the atmosphere (i.e. photolysis and reactions with OH) produces halogen oxide radicals (e.g. ClO, BrO, IO) which have been suggested as the main component of gas-phase halogens. Countries with long coastlines and little land suitable for forestation are investigating the possibility of industrial scale marine kelp farming as a means of carbon sequestration. This marine analogy of the Kyoto Protocol forest has been thought as a means to contribute to climate change mitigation. Knowledge of how natural emissions of VSLS will respond to both the drivers of climate change (e.g. changes in CO2 and land use) and to the consequences of climate change (e.g. changes in sea surface temperature and wind stress) is very limited. As a result, it is imperative that observational studies are performed to quantify the contributions of these natural VSLS to halogen loading in the troposphere and, subsequently, in the stratosphere. For this, transport and degradation processes of the source gases and product gases need to be studied and quantified. A key question surfacing from the WMO Assessment is to what extent halogenated VSLS contribute to atmospheric Bry and Iy. During a field campaign conducted during the spring of 2009, measurements of BrO and IO were made along the coastline of the South Island of New Zealand using a portable Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) spectrometer with the aim of determining coastal sites where high active halogen release could be observed. The selected sites had high biomass concentration of marine algae that would be exposed by low tides. Local macro algae type, tidal height, sunlight, temperature, and wind speed were recorded and correlated to the resulting data in order to better understand the environmental factors that modulate the emissions of halogen oxides from the marine environment to the troposphere. Results of this multi-disciplinary approach to studying brominated VSLS and their atmospheric implications are presented. As well, the chemical processes taking place and producing these halogen oxides are discussed in a thorough manner. This study contributes to a better understanding of the origin of bromine and iodine in the lowermost atmosphere (i.e. marine boundary layer). Particularly, the role that natural emissions of halogenated VSLS from the ocean may play in the halogen budget of the lower atmosphere is addressed by quantitatively understanding key links in this chain so that its potential future impacts on atmospheric chemistry, surface UV radiation, and the biosphere can be thoroughly assessed.

Martian fluid and Martian weathering signatures identified in Nakhla, NWA 998 and MIL 03346 by halogen and noble gas analysis

NASA Astrophysics Data System (ADS)

Cartwright, J. A.; Gilmour, J. D.; Burgess, R.

2013-03-01

We report argon (Ar) noble gas, Ar-Ar ages and halogen abundances (Cl, Br, I) of Martian nakhlites Nakhla, NWA 998 and MIL 03346 to determine the presence of Martian hydrous fluids and weathering products. Neutron-irradiated samples were either crushed and step-heated (Nakhla only), or simply step-heated using a laser or furnace, and analysed for noble gases using an extension of the 40Ar-39Ar technique to determine halogen abundances. The data obtained provide the first isotopic evidence for a trapped fluid that is Cl-rich, has a strong correlation with 40ArXS (40ArXS = 40Armeasured - 40Arradiogenic) and displays 40ArXS/36Ar of ˜1000 - consistent with the Martian atmosphere. This component was released predominantly in the low temperature and crush experiments, which may suggest a fluid inclusion host. For the halogens, we observe similar Br/Cl and I/Cl ratios between the nakhlites and terrestrial reservoirs, which is surprising given the absence of crustal recycling, organic matter and frequent fluid activity on Mars. In particular, Br/Cl ratios in our Nakhla samples (especially olivine) are consistent with previously analysed Martian weathering products, and both low temperature and crush analyses show a similar trend to the evaporation of seawater. This may indicate that surface brines play an important role on Mars and on halogen assemblages within Martian meteorites and rocks. Elevated I/Cl ratios in the low temperature NWA 998 and MIL 03346 releases may relate to in situ terrestrial contamination, though we are unable to distinguish between low temperature terrestrial or Martian components. Whilst estimates of the amount of water present based on the 36Ar concentrations are too high to be explained by a fluid component alone, they are consistent with a mixed-phase inclusion (gas and fluid) or with shock-implanted Martian atmospheric argon. The observed fluid is dilute (low salinity, but high Br/Cl and I/Cl ratios), contains a Martian atmospheric component, and may represent a mixture of a shallow fluid with one derived from fluid circulation within the nakhlite cumulate pile - with heat for fluid circulation supplied by either the igneous intrusion or by an impact event.

Compositional variation in aging volcanic plumes - Analysis of gaseous SO2, CO2 and halogen species in volcanic emissions using an Unmanned Aerial Vehicle (UAV).

NASA Astrophysics Data System (ADS)

Rüdiger, Julian; Lukas, Tirpitz; Bobrowski, Nicole; Gutmann, Alexandra; Liotta, Marcello; de Moor, Maarten; Hoffmann, Thorsten

2017-04-01

Volcanoes are a large source for several reactive atmospheric trace gases including sulfur and halogen containing species. The detailed understanding of volcanic plume chemistry is needed to draw information from gas measurements on subsurface processes. This knowledge is essential for using gas measurements as a monitoring tool for volcanic activity. The reactive bromine species bromine monoxide (BrO) is of particular interest, because BrO as well as SO2 are readily measurable from safe distance by spectroscopic remote sensing techniques. BrO is not directly emitted, but is formed in the plume by a multiphase reaction mechanism. The abundance of BrO changes as a function of the distance from the vent as well as the spatial position in the plume. The precursor substance for the formation of BrO is HBr with Br2as an intermediate product. In this study we present the application of a UAV as a carrier for a remote-controlled sampling system for halogen species (Br2, HBr, BrCl, etc), based on the gas diffusion denuder technique, which allows speciation and enrichment by selective organic reactions. For the analysis of gaseous SO2 and CO2 an in-situ gas monitoring system was additionally mounted. This setup was deployed into the gas plumes of Stromboli Volcano (Italy), Masaya Volcano (Nicaragua) and Turrialba Volcano (Costa Rica) in 2016, to investigate the halogen chemistry at distant locations in the plume further downwind to the emission source, which are in most cases not accessible by other approaches. Flights into the plume were conducted with ascents of up to 1000 m. From telemetrically transmitted SO2 mixing ratios, areas of dense plume where localized to keep the UAV stationary for up to 10 minutes of sampling time. Additionally, ground based samples were taken at the crater rim (at Masaya and Turrialba) using alkaline traps, denuder and gas sensors for comparison with airborne-collected data. Herein we will present time and spatial resolved gas mixing ratio data for SO2, CO2 and halogen species for crater rim sites and a downwind plume age of about 3 to 5 minutes.

Reductions in DNAPL Longevity through Biological Flux Enhancement

DTIC Science & Technology

2009-01-01

3 Phosphorus 2 Calcium 111 Magnesium 11 Sulfur 47 Bioavailable iron 31 Total iron 198 Porosity 0.32 Conductivity 0.97 mmohs cm-1 Organic...acetate, propionate, and lactate were analyzed by filtering aqueous samples (2.7 mL) through a syringe filter (0.22 μm) containing 0.3 M oxalic acid...acid Nitric acid, glycol, peroxides, permanganates Acetone Conc. nitric and sulfuric acids Ammonia, anhydrous Halogens, calcium hypochlorite (bleach

Nontargeted Biomonitoring of Halogenated Organic Compounds in Two Ecotypes of Bottlenose Dolphins (Tursiops truncatus) from the Southern California Bight

PubMed Central

2015-01-01

Targeted environmental monitoring reveals contamination by known chemicals, but may exclude potentially pervasive but unknown compounds. Marine mammals are sentinels of persistent and bioaccumulative contaminants due to their longevity and high trophic position. Using nontargeted analysis, we constructed a mass spectral library of 327 persistent and bioaccumulative compounds identified in blubber from two ecotypes of common bottlenose dolphins (Tursiops truncatus) sampled in the Southern California Bight. This library of halogenated organic compounds (HOCs) consisted of 180 anthropogenic contaminants, 41 natural products, 4 with mixed sources, 8 with unknown sources, and 94 with partial structural characterization and unknown sources. The abundance of compounds whose structures could not be fully elucidated highlights the prevalence of undiscovered HOCs accumulating in marine food webs. Eighty-six percent of the identified compounds are not currently monitored, including 133 known anthropogenic chemicals. Compounds related to dichlorodiphenyltrichloroethane (DDT) were the most abundant. Natural products were, in some cases, detected at abundances similar to anthropogenic compounds. The profile of naturally occurring HOCs differed between ecotypes, suggesting more abundant offshore sources of these compounds. This nontargeted analytical framework provided a comprehensive list of HOCs that may be characteristic of the region, and its application within monitoring surveys may suggest new chemicals for evaluation. PMID:25526519

Human exposures to volatile halogenated organic chemicals in indoor and outdoor air.

PubMed Central

Andelman, J B

1985-01-01

Volatile halogenated organic chemicals are found in indoor and outdoor air, often at concentrations substantially above those in remote, unpopulated areas. The outdoor ambient concentrations vary considerably among sampling stations throughout the United States, as well as diurnally and daily. The vapor pressures and air-water equilibrium (Henry's Law) constants of these chemicals influence considerably the likely relative human exposures for the air and water routes. Volatilization of chemicals from indoor uses of water can be a substantial source of exposure, as shown for radon-222. Measurements of air concentrations of trichloroethylene (TCE) in showers using TCE contaminated groundwater show increases with time to as high as one-third of occupational threshold limit values. Using a scaled down experimental shower, such volatilization and subsequent decay in air was also demonstrated. Using a simplified indoor air model and assuming complete volatilization from a full range of typical water uses within the home, calculations indicate that the expected air inhalation exposures can be substantially higher than those from ingestion of these chemicals in drinking water. Although the regulation of toxic chemicals in potable water supplies has focused traditionally on direct ingestion, the volatilization and inhalation from other much greater volume indoor uses of water should be considered as well. PMID:4085436

Dissolved organic matter composition drives the marine production of brominated very short-lived substances.

PubMed

Liu, Yina; Thornton, Daniel C O; Bianchi, Thomas S; Arnold, William A; Shields, Michael R; Chen, Jie; Yvon-Lewis, Shari A

2015-03-17

Brominated very short-lived substances (BrVSLS), such as bromoform, are important trace gases for stratospheric ozone chemistry. These naturally derived trace gases are formed via bromoperoxidase-mediated halogenation of dissolved organic matter (DOM) in seawater. Information on DOM type in relation to the observed BrVSLS concentrations in seawater, however, is scarce. We examined the sensitivity of BrVSLS production in relation to the presence of specific DOM moieties. A total of 28 model DOM compounds in artificial seawater were treated with vanadium bromoperoxidase (V-BrPO). Our results show a clear dependence of BrVSLS production on DOM type. In general, molecules that comprise a large fraction of the bulk DOM pool did not noticeably affect BrVSLS production. Only specific cell metabolites and humic acid appeared to significantly enhance BrVSLS production. Amino acids and lignin phenols suppressed enzyme-mediated BrVSLS production and may instead have formed halogenated nonvolatile molecules. Dibromomethane production was not observed in any experiments, suggesting it is not produced by the same pathway as the other BrVSLS. Our results suggest that regional differences in DOM composition may explain the observed BrVSLS concentration variability in the global ocean. Ultimately, BrVSLS production and concentrations are likely affected by DOM composition, reactivity, and cycling in the ocean.

Halogenated peptides as internal standards (H-PINS): introduction of an MS-based internal standard set for liquid chromatography-mass spectrometry.

PubMed

Mirzaei, Hamid; Brusniak, Mi-Youn; Mueller, Lukas N; Letarte, Simon; Watts, Julian D; Aebersold, Ruedi

2009-08-01

As the application for quantitative proteomics in the life sciences has grown in recent years, so has the need for more robust and generally applicable methods for quality control and calibration. The reliability of quantitative proteomics is tightly linked to the reproducibility and stability of the analytical platforms, which are typically multicomponent (e.g. sample preparation, multistep separations, and mass spectrometry) with individual components contributing unequally to the overall system reproducibility. Variations in quantitative accuracy are thus inevitable, and quality control and calibration become essential for the assessment of the quality of the analyses themselves. Toward this end, the use of internal standards cannot only assist in the detection and removal of outlier data acquired by an irreproducible system (quality control) but can also be used for detection of changes in instruments for their subsequent performance and calibration. Here we introduce a set of halogenated peptides as internal standards. The peptides are custom designed to have properties suitable for various quality control assessments, data calibration, and normalization processes. The unique isotope distribution of halogenated peptides makes their mass spectral detection easy and unambiguous when spiked into complex peptide mixtures. In addition, they were designed to elute sequentially over an entire aqueous to organic LC gradient and to have m/z values within the commonly scanned mass range (300-1800 Da). In a series of experiments in which these peptides were spiked into an enriched N-glycosite peptide fraction (i.e. from formerly N-glycosylated intact proteins in their deglycosylated form) isolated from human plasma, we show the utility and performance of these halogenated peptides for sample preparation and LC injection quality control as well as for retention time and mass calibration. Further use of the peptides for signal intensity normalization and retention time synchronization for selected reaction monitoring experiments is also demonstrated.

Environmentally relevant organophosphate triesters in herring gulls: In vitro biotransformation and kinetics and diester metabolite formation using a hepatic microsomal assay.

PubMed

Greaves, Alana K; Su, Guanyong; Letcher, Robert J

2016-10-01

The in vitro biotransformation and kinetics of six organophosphate triester (OPE) flame retardants were investigated in herring gulls (Larus argentatus) from the Great Lakes using a hepatic microsomal metabolism assay. Administration of each individual OPE (tri-n-butyl phosphate (TNBP), tris(2-butoxyethyl) phosphate (TBOEP), triphenyl phosphate (TPHP), triethyl phosphate (TEP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris(2-chloroisopropyl) phosphate (TCIPP)) to the in vitro assay (concentration range 0.01 to 10μM) resulted in rapid depletion with the exception of TEP. Following the Michaelis-Menten enzyme kinetics model, a preliminary 2-minute incubation period was used to estimate the Vmax (±SE) values (i.e., the maximal rate of reaction for a saturated enzyme system), which ranged from 5.0±0.4 (TPHP) to 29±18pmol/min/mg protein (TBOEP), as well as the KM (±SE) values (i.e., the OPE concentration corresponding to one half of the Vmax), which ranged from 9.8±1 (TPHP) to 189±135nM (TBOEP). Biotransformation assays over a 100-minute incubation period revealed that TNBP was metabolized most rapidly (with a depletion rate of 73±4pmol/min/mg protein), followed by TBOEP (53±8pmol/min/mg), TCIPP (27±1pmol/min/mg), TPHP (22±2pmol/min/mg) and TDCIPP (8±1pmol/min/mg). In vitro biotransformation of OP triesters was clearly structure-dependent where non-halogenated alkyl OP triesters were metabolized more rapidly than halogenated alkyl triesters. Halogenated OP triesters were transformed to their respective diesters more efficiently relative to non-halogenated OP triesters. To our knowledge, this is the first study to investigate OP triester metabolism and OP diester formation in an avian or wildlife model system, which is important to understand the fate and biological activity of OPEs in an exposed organism. Copyright © 2016 Elsevier Inc. All rights reserved.

Halogenated Peptides as Internal Standards (H-PINS)

PubMed Central

Mirzaei, Hamid; Brusniak, Mi-Youn; Mueller, Lukas N.; Letarte, Simon; Watts, Julian D.; Aebersold, Ruedi

2009-01-01

As the application for quantitative proteomics in the life sciences has grown in recent years, so has the need for more robust and generally applicable methods for quality control and calibration. The reliability of quantitative proteomics is tightly linked to the reproducibility and stability of the analytical platforms, which are typically multicomponent (e.g. sample preparation, multistep separations, and mass spectrometry) with individual components contributing unequally to the overall system reproducibility. Variations in quantitative accuracy are thus inevitable, and quality control and calibration become essential for the assessment of the quality of the analyses themselves. Toward this end, the use of internal standards cannot only assist in the detection and removal of outlier data acquired by an irreproducible system (quality control) but can also be used for detection of changes in instruments for their subsequent performance and calibration. Here we introduce a set of halogenated peptides as internal standards. The peptides are custom designed to have properties suitable for various quality control assessments, data calibration, and normalization processes. The unique isotope distribution of halogenated peptides makes their mass spectral detection easy and unambiguous when spiked into complex peptide mixtures. In addition, they were designed to elute sequentially over an entire aqueous to organic LC gradient and to have m/z values within the commonly scanned mass range (300–1800 Da). In a series of experiments in which these peptides were spiked into an enriched N-glycosite peptide fraction (i.e. from formerly N-glycosylated intact proteins in their deglycosylated form) isolated from human plasma, we show the utility and performance of these halogenated peptides for sample preparation and LC injection quality control as well as for retention time and mass calibration. Further use of the peptides for signal intensity normalization and retention time synchronization for selected reaction monitoring experiments is also demonstrated. PMID:19411281

Halogenated naphthyl methoxy piperidines for mapping serotonin transporter sites

DOEpatents

Goodman, Mark M.; Faraj, Bahjat

1999-01-01

Halogenated naphthyl methoxy piperidines having a strong affinity for the serotonin transporter are disclosed. Those compounds can be labeled with positron-emitting and/or gamma emitting halogen isotopes by a late step synthesis that maximizes the useable lifeterm of the label. The labeled compounds are useful for localizing serotonin transporter sites by positron emission tomography and/or single photon emission computed tomography.

Halogenated naphthyl methoxy piperidines for mapping serotonin transporter sites

DOEpatents

Goodman, M.M.; Faraj, B.

1999-07-06

Halogenated naphthyl methoxy piperidines having a strong affinity for the serotonin transporter are disclosed. Those compounds can be labeled with positron-emitting and/or gamma emitting halogen isotopes by a late step synthesis that maximizes the useable lifeterm of the label. The labeled compounds are useful for localizing serotonin transporter sites by positron emission tomography and/or single photon emission computed tomography.

Halogenated compounds from marine algae.

PubMed

Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

2010-08-09

Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds.

Halogenated Compounds from Marine Algae

PubMed Central

Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

2010-01-01

Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds. PMID:20948909

Investigating Planetary Volatile Accretion Mechanisms Using the Halogens

NASA Astrophysics Data System (ADS)

Ballentine, C. J.; Clay, P. L.; Burgess, R.; Busemann, H.; Ruzié, L.; Joachim, B.; Day, J. M.

2014-12-01

Depletion of the volatile elements in the Earth relative to the CI chondrites is roughly correlated with volatility, or decreasing condensation temperature. For the heavy halogen group elements (Cl, Br and I), volatility alone does not account for their apparent depletion, which early data has suggested is far greater than predicted [1-2]. Such depletion has been used to argue for the preferential loss of halogens by, amongst other processes, impact-driven erosive loss from Earth's surface [2]. Little consensus exists as to why the halogens should exhibit such preferential behavior during accretionary processes. Early efforts to constrain halogen abundance and understand their behavior in both Earth and planetary materials [3-6] have been hampered by their typically low abundance (ppb level) in most geologic materials. We present the results of halogen analysis of 23 chondrite samples, selected to represent diverse groups and petrologic type. Halogen abundances were measured by neutron irradiation noble gas mass spectrometry (NI-NGMS). Significant concentration heterogeneity is observed within some samples. However, a single Br/Cl and I/Cl ratio of 1.9 ± 0.2 (x 10-3) and 335 ± 10 (x 10-6) can be defined for carbonaceous chondrites with a good correlation between Br and Cl (R2 = 0.97) and between I and Cl (R2 = 0.84). Ratios of I/Cl overlap with terrestrial estimates of Bulk Silicate Earth and Mid Ocean Ridge Basalts. Similarly, good correlations are derived for enstatite (E) chondrites and a sulfide- and halogen- rich subset of E-chondrites. Chlorine abundances of CI (Orgueil) in this study are lower by factor of ~ 3 than the value of ~ 700 ppm Cl (compilation in [1]). Our results are similar to early discarded low values for Ivuna and Orgueil from [5,6] and agree more closely with values for CM chondrites. Halogens may not be as depleted in Earth as previously suggested, or a high degree of heterogeneity in the abundance of these volatile elements in carbonaceous chondrites should be considered when we assess Earth's halogen abundance relative to CI. [1] Lodders (2003) Astr J 591:1220-47. [2] Sharp et al. (2013) EPSL 369/70: 71-7. [3] Dreibus et al. (1979) Phys Chem Earth 11:33-8. [4] Goles et al. (1967) GCA 31: 1771-7. [5] Reed and Allen (1966) GCA 30: 779-800. [6] Greenland & Lovering (1965) GCA 29: 821-58.

Chemical cleaning-associated generation of dissolved organic matter and halogenated byproducts in ceramic MBR: Ozone versus hypochlorite.

PubMed

Sun, Huifang; Liu, Hang; Han, Jiarui; Zhang, Xiangru; Cheng, Fangqin; Liu, Yu

2018-09-01

This study characterized the dissolved organic matter (DOM) and byproducts generated after the exposure of activated sludge to ozone and NaClO in ceramic MBR. It was found that NaClO triggered more significant release of DOM than ozone. Proteins with the molecular weight greater than 20 kDa and humic acid like-substances were the principal components of DOM generated by NaClO, while ozone was found to effectively degrade larger biopolymers to low molecular weight substances. The results showed that more than 80% of DOM generated by NaClO and ozone could pass through the 0.2-μm ceramic membrane. Furthermore, total organic chlorine (TOCl) was determined to be the principal species of halogenated byproducts in both cases, while the generation of TOCl by NaClO was much more significant than that by ozone. Only a small fraction of TOCl was removed by the 0.2-μm ceramic membrane. More importantly, the toxic bioassays further revealed that the supernatant of sludge suspension and permeate in the MBR with NaClO cleaning exhibited higher developmental toxicity to the polychaete embryos than those by ozone. The results clearly showed that on-line chemical cleaning with ozone should be a more eco-friendly and safer approach for sustaining long-term membrane permeability in ceramic MBR. Copyright © 2018 Elsevier Ltd. All rights reserved.

Tribromobenzene on Cu(111): Temperature-dependent formation of halogen-bonded, organometallic, and covalent nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Qitang; Wang, Tao; Zhu, Junfa, E-mail: jfzhu@ustc.edu.cn

2015-03-14

The temperature-controlled surface-assisted synthesis of halogen bonded, organometallic, and covalent nanostructures based on 1,3,5-tribromo-benzene (TriBB) was studied with scanning tunneling microscopy and X-ray photoemission spectroscopy in ultrahigh vacuum. Vapor deposition of TriBB onto a Cu(111) surface held at 90 K leads to the formation of large domains of a honeycomb-like organic monolayer structure stabilized by triangular nodes with Br⋯Br intermolecular bonds. Upon annealing the organic monolayer to ∼140 K, a new hexagonal close-packed structure with intact TriBB molecules connected by Cu adatoms is formed. Further warming up the sample to 300 K gives rise to the scission of C–Br bondsmore » and formation of C–Cu–C bonds between phenyl fragments such that stable dendritic organometallic networks are formed. Larger islands of organometallic networks are obtained by maintaining the temperature of Cu(111) at 420 K during deposition of TriBB. Simultaneously, large islands of Br atoms are formed around the organometallic networks. Annealing the more extended organometallic network (prepared at 420 K) to 520 K leads to the formation of a branched covalent organic framework (COF) which comprises structural elements of porous graphene and is surrounded by Br islands. These organometallic networks and COFs appear as small dendritic and branched domains, most likely due to the steric influence exerted by the Br islands.« less

Use of thermal analysis techniques (TG-DSC) for the characterization of diverse organic municipal waste streams to predict biological stability prior to land application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez, Jose M., E-mail: joseman@sas.upenn.edu; Plaza, Cesar; Polo, Alfredo

2012-01-15

Highlights: Black-Right-Pointing-Pointer Thermal analysis was used to assess stability and composition of organic matter in three diverse municipal waste streams. Black-Right-Pointing-Pointer Results were compared with C mineralization during 90-day incubation, FTIR and {sup 13}C NMR. Black-Right-Pointing-Pointer Thermal analysis reflected the differences between the organic wastes before and after the incubation. Black-Right-Pointing-Pointer The calculated energy density showed a strong correlation with cumulative respiration. Black-Right-Pointing-Pointer Conventional and thermal methods provide complimentary means of characterizing organic wastes. - Abstract: The use of organic municipal wastes as soil amendments is an increasing practice that can divert significant amounts of waste from landfill, and providesmore » a potential source of nutrients and organic matter to ameliorate degraded soils. Due to the high heterogeneity of organic municipal waste streams, it is difficult to rapidly and cost-effectively establish their suitability as soil amendments using a single method. Thermal analysis has been proposed as an evolving technique to assess the stability and composition of the organic matter present in these wastes. In this study, three different organic municipal waste streams (i.e., a municipal waste compost (MC), a composted sewage sludge (CS) and a thermally dried sewage sludge (TS)) were characterized using conventional and thermal methods. The conventional methods used to test organic matter stability included laboratory incubation with measurement of respired C, and spectroscopic methods to characterize chemical composition. Carbon mineralization was measured during a 90-day incubation, and samples before and after incubation were analyzed by chemical (elemental analysis) and spectroscopic (infrared and nuclear magnetic resonance) methods. Results were compared with those obtained by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Total amounts of CO{sub 2} respired indicated that the organic matter in the TS was the least stable, while that in the CS was the most stable. This was confirmed by changes detected with the spectroscopic methods in the composition of the organic wastes due to C mineralization. Differences were especially pronounced for TS, which showed a remarkable loss of aliphatic and proteinaceous compounds during the incubation process. TG, and especially DSC analysis, clearly reflected these differences between the three organic wastes before and after the incubation. Furthermore, the calculated energy density, which represents the energy available per unit of organic matter, showed a strong correlation with cumulative respiration. Results obtained support the hypothesis of a potential link between the thermal and biological stability of the studied organic materials, and consequently the ability of thermal analysis to characterize the maturity of municipal organic wastes and composts.« less

Effect of electric signal frequency and form on physical-chemical oxidation of organic wastes

NASA Astrophysics Data System (ADS)

Morozov, Yegor; Tikhomirov, Alexander A.; Trifonov, Sergey V.; Kudenko, D.. Yurii A.

The behavior conditions of physical-chemical reactions securing organic wastes’ oxidation in H _{2}O _{2} aqueous medium aimed at an increase of mass exchange processes in a life support system (LSS) for a space purpose have been under study. The character of dependence of organic wastes oxidation rate in H _{2}O _{2} aqueous medium, activated with alternating current of different frequency and form have been considered. Ways of those parameters optimization for the purpose to efficiently increase the physical-chemical decomposition of organic wastes in LSS have been proposed. Specifically, power consumption and reaction time of wastes mineralization have been determined to reduce more than twice. Involvement ways of mineralized organic wastes received in intrasystem mass exchange have been shown. Application feasibility of the obtained results both for space and terrestrial purpose has been discussed. Key words: life support sustem, mineralization, turnover, frequency, organic wastes

Halogen Chemistry at North American Coastal Sites

NASA Astrophysics Data System (ADS)

Stutz, J.; Pikelnaya, O.; Laskin, A.; Sumner, A.; Jobson, B. T.; Finley, B.; Lawler, M.; Saltzman, E. S.; Pszenny, A. A.; Deegan, B.

2007-12-01

In recent years observational evidence has emerged that reactive halogen species (RHS), such as chlorine atoms, and bromine and iodine oxides, are present in coastal areas. Their chemistry can be significant as they catalytically destroy O3; oxidize hydrocarbons, dimethylsulfide, and S(IV); and modify NOx and HOx cycling. Despite their potential importance our observational database on RHS is still very limited. Most observations of RHS thus far have been made in clean areas and very few observations along the North American coast have been made. Here we will review our current understanding of RHS chemistry in both clean and polluted environments. Recent observations at coastal areas around the world will be discussed. We will also give an overview of an experiment performed by our group in Malibu, CA in October 2006 and present initial results. A suite of trace gases and environmental parameters, including halogen molecules, halogen oxides, Cl + VOC reaction products, aerosol composition, O3, NOx, CO, VOCs, meteorology, and radiation, were measured during a three week period. In addition, Cl + VOC reaction products were measured at two locations in urban Los Angeles. Clear evidence for the presence of various halogen species on the California coast was found. Observations during periods with relatively clean marine air and during times where our site was in the outflow of Los Angeles show the impact of pollution on coastal atmospheric chemistry. Our observations will be compared to earlier studies of halogen chemistry at coastal areas to further advance our understanding of halogen chemistry.

Syntheses of halogen derivatives of L-tryptophan, L-tyrosine and L-phenylalanine labeled with hydrogen isotopes.

PubMed

Pająk, Małgorzata; Pałka, Katarzyna; Winnicka, Elżbieta; Kańska, Marianna

2016-01-01

Halogenated, labeled with tritium and doubly with deuterium and tritium, derivatives of L-tryptophan, i.e. 5'-bromo-[2-(3)H]-, 5'-bromo-[2-(2)H/(3)H]-, 5'-fluoro-[2-(3)H]-5'-fluoro-[2-(2)H/(3)H]-, 6'-fluoro-[2-(3)H]-, 6'-fluoro-[2-(2)H/(3)H]-L-tryptophan, as well as, L-tyrosine, i.e. 3'-fluoro-[2-(3)H]-, 3'-fluoro-[2-(2)H/(3)H]-, 3'-chloro-[2-(3)H]-, and 3'-chloro-[2-(2)H/(3)H]-L-tyrosine, and also L-phenylalanine, i.e. 2'-fluoro-[(3S)-(3)H]-, 2'-fluoro-[(3S)-(2)H/(3) H]-, 2'-chloro-[(3S)-(3)H]-, 2'-chloro-[(3S)-(2)H/(3)H]-, 4'-chloro-[(3S)-(3)H]-, and 4'-chloro-[(3S)-(2)H/(3)H]-L-phenylalanine were synthesized using enzymatic methods. Isotopomers of L-tryptophan were synthesized by coupling of halogenated indoles with S-methyl-L-cysteine carried out in deuteriated or tritiated incubation media. Labeled halogenated derivatives of L-tyrosine were obtained by the enzymatically supported exchange between halogenated L-tyrosine and isotopic water. Labeled halogenated isotopologues of L-Phe were synthesized by the enzymatic addition of ammonia to halogenated cinnamic acid. As a source of hydrogen tritiated water (HTO) and heavy water (D2O) with addition of HTO were used. Copyright © 2015 John Wiley & Sons, Ltd.

Sorption of halogenated phenols and pharmaceuticals to biochar: affecting factors and mechanisms.

PubMed

Oh, Seok-Young; Seo, Yong-Deuk

2016-01-01

The feasibility of using biochar as a sorbent to remove nine halogenated phenols (2,4-dichlorophenol, 2,4-dibromophenol, 2,4-difluorophenol, 2-chlorophenol, 4-chlorophenol, 2-bromophenol, 4-bromophenol, 2-fluorophenol, and 4-fluorophenol) and two pharmaceuticals (triclosan and ibuprofen) from water was examined through a series of batch experiments. Types of biochar, synthesized using various biomasses including fallen leaves, rice straw, corn stalk, used coffee grounds, and biosolids, were evaluated. Compared to granular activated carbon (GAC), most of the biochar samples did not effectively remove halogenated phenols or pharmaceuticals from water. The increase in pH and deprotonation of phenols in biochar systems may be responsible for its ineffectiveness at this task. When pH was maintained at 4 or 7, the sorption capacity of biochar was markedly increased. Considering maximum sorption capacity and properties of sorbents and sorbates, it appears that the sorption capacity of biochar for halogenated phenols is related to the surface area and carbon content of the biochar and the hydrophobicity of halogenated phenols. In the cases of triclosan and ibuprofen, the sorptive capacities of GAC, graphite, and biochars were also significantly affected by pH, according to the point of zero charge (PZC) of sorbents and deprotonation of the pharmaceuticals. Pyrolysis temperature did not affect the sorption capacity of halogenated phenols or pharmaceuticals. Based on the experimental observations, some biochars are good candidates for removal of halogenated phenols, triclosan, and ibuprofen from water and soil.

Anaerobic digestion of organic waste in Japan: the first demonstration plant at Kyoto City.

PubMed

Komatsu, T; Kimura, T; Kuriyama, Y; Isshiki, Y; Kawano, T; Hirao, T; Masuda, M; Yokoyama, K; Matsumoto, T; Takeda, M

2002-01-01

Recycling of Municipal Solid Waste is vigorously promoted in Japan and the necessity of energy recovery from organic waste is increasing. An anaerobic digestion demonstration plant for organic waste in Kyoto City, Japan has been operated for about two years. Three kinds of wastes (garbage and leftovers from hotels, yard waste and used paper) mixed at various ratios are used. The plant has maintained stable operations with each mixture, generating biogas by the decomposition of VS at the rate of about 820 m3N/ton-VS.

Halocarbon ozone depletion and global warming potentials

NASA Technical Reports Server (NTRS)

Cox, Richard A.; Wuebbles, D.; Atkinson, R.; Connell, Peter S.; Dorn, H. P.; Derudder, A.; Derwent, Richard G.; Fehsenfeld, F. C.; Fisher, D.; Isaksen, Ivar S. A.

1990-01-01

Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global warming).

Photoinactivation and Toxicity of Nano-sized TiO2 on Paint Microflora Using Visible Lights

NASA Astrophysics Data System (ADS)

Obidi, Olayide; Halverson, Larry

2016-04-01

Traditional TiO2 has been used as an antimicrobial additive to paints, but more recently the use of TiO2 nanoparticles (NPs) has been proposed as an alternative because of its ability to induce oxidative damage to the cell membrane of bacteria. This study focused on how photoinactivation of TiO2 NPs by fluorescent and halogen lights (400-700 nm) influenced survival of Bacillus sphaericus (Gram-positive bacterium) and Klebsiella pneumoniae (Gram-negative bacterium) isolated from spoiled paints. The loss of viability of the test organisms in the presence of TiO2 NPs determined by culturable (plate) count technique indicated a decrease in viable bacteria that was predominant after 24-h exposure. The TiO2 NPs showed higher antibacterial performance under fluorescent light than halogen light with increasing irradiation time and confirms the photokilling effect of TiO2 NPs. TiO2 NPs were also bactericidal under dark conditions, suggesting potential antibacterial applications in the paint industry.

Spatially resolved analysis of short-range structure perturbations in a plastically bent molecular crystal

NASA Astrophysics Data System (ADS)

Panda, Manas K.; Ghosh, Soumyajit; Yasuda, Nobuhiro; Moriwaki, Taro; Mukherjee, Goutam Dev; Reddy, C. Malla; Naumov, Panče

2015-01-01

The exceptional mechanical flexibility observed with certain organic crystals defies the common perception of single crystals as brittle objects. Here, we describe the morphostructural consequences of plastic deformation in crystals of hexachlorobenzene that can be bent mechanically at multiple locations to 360° with retention of macroscopic integrity. This extraordinary plasticity proceeds by segregation of the bent section into flexible layers that slide on top of each other, thereby generating domains with slightly different lattice orientations. Microscopic, spectroscopic and diffraction analyses of the bent crystal showed that the preservation of crystal integrity when stress is applied on the (001) face requires sliding of layers by breaking and re-formation of halogen-halogen interactions. Application of stress on the (100) face, in the direction where π···π interactions dominate the packing, leads to immediate crystal disintegration. Within a broader perspective, this study highlights the yet unrecognized extraordinary malleability of molecular crystals with strongly anisotropic supramolecular interactions.

Organic compounds in re-circulated leachates of aerobic biological treated municipal solid waste.

PubMed

Franke, Matthias; Jandl, Gerald; Leinweber, Peter

2006-10-01

Biodegradation of organic matter is required to reduce the potential of municipal solid waste for producing gaseous emissions and leaching contaminants. Therefore, we studied leachates of an aerobic-treated waste from municipal solids and a sewage sludge mixture that were re-circulated to decrease the concentration of biodegradable organic matter in laboratory-scale reactors. After 12 months, the total organic C and biological and chemical oxygen demands were reduced, indicating the biodegradation of organic compounds in the leachates. Curie-point pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and pyrolysis-field ionization mass spectrometry (Py-FIMS) revealed that phenols, alkylaromatic compounds, N-containing compounds and carbohydrates were the predominate compounds in the leachates and solid waste. Leachate re-circulation led to a higher thermal stability of the residual organic matter as indicated by temperature-resolved Py-FIMS. Admixture of sewage sludge to solid waste was less effective in removing organic compounds from the leachates. It resulted in drastic higher and more bio-resistant loads of organic matter in the leachates and revealed increased proportions of alkylaromatic compounds. The biodegradation of organic matter in leachates, re-circulated through municipal solid waste, offers the potential for improved aerobic waste treatments and should be investigated on a larger scale.

Prospects of effective microorganisms technology in wastes treatment in Egypt.

PubMed

Shalaby, Emad A

2011-06-01

Sludge dewatering and treatment may cost as much as the wastewater treatment. Usually large proportion of the pollutants in wastewater is organic. They are attacked by saprophytic microorganisms, i.e. organisms that feed upon dead organic matter. Activity of organisms causes decomposition of organic matter and destroys them, where the bacteria convert the organic matter or other constituents in the wastewater to new cells, water, gases and other products. Demolition activities, including renovation/remodeling works and complete or selective removal/demolishing of existing structures either by man-made processes or by natural disasters, create an extensive amount of wastes. These demolition wastes are characterized as heterogeneous mixtures of building materials that are usually contaminated with chemicals and dirt. In developing countries, it is estimated that demolition wastes comprise 20% to 30% of the total annual solid wastes. In Egypt, the daily quantity of construction and demolition (C&D) waste has been estimated as 10 000 tones. That is equivalent to one third of the total daily municipal solid wastes generated per day in Egypt. The zabbaliin have since expanded their activities and now take the waste they collect back to their garbage villages where it is sorted into recyclable components: paper, plastics, rags, glass, metal and food. The food waste is fed to pigs and the other items are sold to recycling centers. This paper summarizes the wastewater and solid wastes management in Egypt now and future.

Evaluating the biochemical methane potential (BMP) of low-organic waste at Danish landfills.

PubMed

Mou, Zishen; Scheutz, Charlotte; Kjeldsen, Peter

2014-11-01

The biochemical methane potential (BMP) is an essential parameter when using first order decay (FOD) landfill gas (LFG) generation models to estimate methane (CH4) generation from landfills. Different categories of waste (mixed, shredder and sludge waste) with a low-organic content and temporarily stored combustible waste were sampled from four Danish landfills. The waste was characterized in terms of physical characteristics (TS, VS, TC and TOC) and the BMP was analyzed in batch tests. The experiment was set up in triplicate, including blank and control tests. Waste samples were incubated at 55°C for more than 60 days, with continuous monitoring of the cumulative CH4 generation. Results showed that samples of mixed waste and shredder waste had similar BMP results, which was in the range of 5.4-9.1 kg CH4/ton waste (wet weight) on average. As a calculated consequence, their degradable organic carbon content (DOCC) was in the range of 0.44-0.70% of total weight (wet waste). Numeric values of both parameters were much lower than values of traditional municipal solid waste (MSW), as well as default numeric values in current FOD models. The sludge waste and temporarily stored combustible waste showed BMP values of 51.8-69.6 and 106.6-117.3 kg CH4/ton waste on average, respectively, and DOCC values of 3.84-5.12% and 7.96-8.74% of total weight. The same category of waste from different Danish landfills did not show significant variation. This research studied the BMP of Danish low-organic waste for the first time, which is important and valuable for using current FOD LFG generation models to estimate realistic CH4 emissions from modern landfills receiving low-organic waste. Copyright © 2014 Elsevier Ltd. All rights reserved.

The participation of community-based organizations on waste management in the city municipal of Medan

NASA Astrophysics Data System (ADS)

Trimurni, Februati; Dayana

2018-03-01

Waste is currently main problem experienced by cities all over the world. The waste has brought negative impacts on public health, environment, development and social of the cities. However, there must be solutions to overcome the piles of waste in case the individual citizens or community-based organization wisely deal with the problem. In the municipal area of Medan in the Province of North Sumatra, there is sort of organization established by community-based organization (CBO) so-called Bank Sampah or Waste Bank which is placed as a flatform for the member to do business of waste materials by collecting them from households around, sorting the materials into waste categories and ended up by purchasing and selling them to make some money. The organization is not merely a flatform for doing a business of waste materials yet the media for other social activities and efforts of reaching social and family welfare. The study is conducted in some sites of such organization activities in the city, and there are some observations of how the community run the business and in the same time arranging other social activities. The study tries to portray the activities and analyzes the means and the significancy of the CBO on reducing waste problems in the city.

40 CFR Table 3 to Subpart Ffff of... - Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP Metals Emissions From...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Emission Limits for Hydrogen Halide and... to Subpart FFFF of Part 63—Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP... following table that applies to your process vents that contain hydrogen halide and halogen HAP emissions or...

40 CFR Table 3 to Subpart Ffff of... - Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP Metals Emissions From...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Emission Limits for Hydrogen Halide and... to Subpart FFFF of Part 63—Emission Limits for Hydrogen Halide and Halogen HAP Emissions or HAP... following table that applies to your process vents that contain hydrogen halide and halogen HAP emissions or...

40 CFR 63.2465 - What requirements must I meet for process vents that emit hydrogen halide and halogen HAP or HAP...

Code of Federal Regulations, 2011 CFR

2011-07-01

... process vents that emit hydrogen halide and halogen HAP or HAP metals? 63.2465 Section 63.2465 Protection... Compliance Requirements § 63.2465 What requirements must I meet for process vents that emit hydrogen halide... section. (b) If any process vents within a process emit hydrogen halide and halogen HAP, you must...

Improved Method of Purifying Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Delzeit, Lance D.

2004-01-01

An improved method of removing the residues of fabrication from carbon nanotubes has been invented. These residues comprise amorphous carbon and metal particles that are produced during the growth process. Prior methods of removing the residues include a variety of processes that involved the use of halogens, oxygen, or air in both thermal and plasma processes. Each of the prior methods entails one or more disadvantages, including non-selectivity (removal or damage of nanotubes in addition to removal of the residues), the need to dispose of toxic wastes, and/or processing times as long as 24 hours or more. In contrast, the process described here does not include the use of toxic chemicals, the generation of toxic wastes, causes little or no damage to the carbon nanotubes, and involves processing times of less than 1 hour. In the improved method, purification is accomplished by flowing water vapor through the reaction chamber at elevated temperatures and ambient pressures. The impurities are converted to gaseous waste products by the selective hydrogenation and hydroxylation by the water in a reaction chamber. This process could be performed either immediately after growth or in a post-growth purification process. The water used needs to be substantially free of oxygen and can be obtained by a repeated freeze-pump-thaw process. The presence of oxygen will non-selectively attach the carbon nanotubes in addition to the amorphous carbon.

Use of thermal analysis techniques (TG-DSC) for the characterization of diverse organic municipal waste streams to predict biological stability prior to land application.

PubMed

Fernández, José M; Plaza, César; Polo, Alfredo; Plante, Alain F

2012-01-01

The use of organic municipal wastes as soil amendments is an increasing practice that can divert significant amounts of waste from landfill, and provides a potential source of nutrients and organic matter to ameliorate degraded soils. Due to the high heterogeneity of organic municipal waste streams, it is difficult to rapidly and cost-effectively establish their suitability as soil amendments using a single method. Thermal analysis has been proposed as an evolving technique to assess the stability and composition of the organic matter present in these wastes. In this study, three different organic municipal waste streams (i.e., a municipal waste compost (MC), a composted sewage sludge (CS) and a thermally dried sewage sludge (TS)) were characterized using conventional and thermal methods. The conventional methods used to test organic matter stability included laboratory incubation with measurement of respired C, and spectroscopic methods to characterize chemical composition. Carbon mineralization was measured during a 90-day incubation, and samples before and after incubation were analyzed by chemical (elemental analysis) and spectroscopic (infrared and nuclear magnetic resonance) methods. Results were compared with those obtained by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Total amounts of CO(2) respired indicated that the organic matter in the TS was the least stable, while that in the CS was the most stable. This was confirmed by changes detected with the spectroscopic methods in the composition of the organic wastes due to C mineralization. Differences were especially pronounced for TS, which showed a remarkable loss of aliphatic and proteinaceous compounds during the incubation process. TG, and especially DSC analysis, clearly reflected these differences between the three organic wastes before and after the incubation. Furthermore, the calculated energy density, which represents the energy available per unit of organic matter, showed a strong correlation with cumulative respiration. Results obtained support the hypothesis of a potential link between the thermal and biological stability of the studied organic materials, and consequently the ability of thermal analysis to characterize the maturity of municipal organic wastes and composts. Copyright © 2011 Elsevier Ltd. All rights reserved.

Environmental risk assessment of the use of different organic wastes as soil amendments

NASA Astrophysics Data System (ADS)

Alvarenga, Paula; Palma, Patrícia; Mourinha, Clarisse; Farto, Márcia; Cunha-Queda, Ana Cristina; Natal-da-Luz, Tiago; Sousa, José Paulo

2013-04-01

The use of organic wastes in agriculture is considered a way of maintaining or restoring the quality of soils, enlarging the slow cycling soil organic carbon pool. However, a wide variety of undesired substances, such as potentially trace elements and organic contaminants, can have adverse effects on the environment. That fact was highlighted by the Proposal for a Soil Framework Directive, which recognized that "soil degradation or soil improvements have a major impact on other areas, (…) such as surface waters and groundwater, human health, climate change, protection of nature and biodiversity, and food safety". Taking that into account, the research project "ResOrgRisk" aims to assess the environmental risk involved in the use of different organic wastes as soil amendments, evidencing their benefits and constraints, and defining the most suitable tests to reach such assessment. The organic wastes selected for this purpose were: sewage sludge, limed, not limed, and co-composted with agricultural wastes, agro-industrial sludge, mixed municipal solid waste compost, compost produced from organic farming residues, and pig slurry digestate. Whereas threshold values for heavy metals in sludge used for agriculture have been set by the European Commission, actually there is no definitive European legislation for organic contaminants. Guide values for some organic contaminants (e.g. polychlorinated biphenyls - PCBs, and polycyclic aromatic hydrocarbons - PAHs) have been adopted at national level by many European countries, such as Portugal. These values should be taken into account when assessing the risk involved in the use of organic wastes as soil amendments. However, chemical analysis of organic waste often gives scarce information because it does not include possible interactions between chemicals. Furthermore, an exhaustive identification and quantification of all substances is impractical. In this study, ecotoxicological tests (comprising solid and aquatic phases) were performed to obtain an integrated assessment on the effects of all contaminants from each organic waste, as a whole, to terrestrial systems. The results for the chemical and ecotoxicological characterization of the organic wastes selected in this study will be discussed, emphasizing the potential benefits and the risks of their use as soil amendments.