Polybromine phases

A variety of complexes exists in solid or liquid state at ambient temperature, in the range required for battery operation. Liquid polybromine phases are preferred since they enable storage of the active material externally to the electrochemical cell stack in a tank, hence enhancing the... 

As shown by several investigations [91], the bromine-rich polybromide phase by itself is hardly flammable and fireextinguishing properties have been reported occasionally. The formation of polybrominated dibenzo-dioxins (PBrDD) and furans (PBrDF) due to the plastic-containing housing of a zinc-flow battery cannot be totally neglected in the case of a fire, but their concentrations are far away from the tetrachloro dibenzodioxine (TCDD) toxic equivalents even in a worst-case scenario. 

The replacement of established chemistries with newer ones is one of the classic drivers of change in the chemical industry. One of the current hotbeds of this kind of change is the replacement of brominated flame retardants in polymer formulations. The brominated flame retardants under the most scrutiny have been polybrominated diphenyl ethers, particularly penta- and octabromodiphenyl ether, which have been shown to be persistent in the environment and to bioaccumulate. Great Lakes Chemical is voluntarily phasing out penta- and octa-BDEs by the end of next year. The phaseout is made possible by the clean bill of health granted by EPA for Firemaster 550, a replacement for penta-BDE in flexible PU applications. BRG Townsend claims the phaseout of penta-BDE and octa-BDE is not as earth shattering as would be an exit from deca-BDE, a styrenics additive that is produced in the highest volume of the PBDEs. 

Polybrominated Biphenyls. PBBs existed predominantly in the particulate phase in the atmosphere. Particulate phase PBBs are removed from the atmosphere by wet and dry deposition and should not travel long distances in the environment. In water, PBBs are expected to absorb strongly to suspended solids and sediment, and may bioconcentrate in aquatic organisms. The volatilization of PBBs from water to air is not expected to be important due to attenuation by adsorption in the water column. In soil, PBBs are adsorbed strongly and will be immobile. Volatilization of PBBs from soil to air is not important due to the low volatility of PBBs and strong adsorption of PBBs to soil. 

Polybrominated Diphenyl Ethers. In air, highly brominated PBDEs, which have low vapor pressures and exist in the particulate phase, will be removed from the atmosphere by wet and dry deposition. 

Polybrominated Biphenyls. In air, the two processes that may result in significant degradation or transformation of PBBs are photooxidation by hydroxyl radicals and direct photolysis. The estimated half-life of pentachlorobiphenyl in air due to reaction with hydroxyl radicals is 41.6 83.2 days (Atkinson 1987a). Based on a structure-activity relationship for the estimation of half-lives for the gas-phase reactions of hydroxyl radicals with organic compounds (Atkinson 1987b), the estimated half-lives of hexabromobiphenyl and decabromobiphenyl due to reaction with OH radicals are 182 and 2,448 days, respectively. These half-lives are consistent with the half-life of pentachlorobiphenyl due to reaction with OH radicals. However, the half-lives of brominated biphenyls expected to be present in the particulate phase in the air may be even longer than the estimated half-lives due to gas phase reaction. Therefore, the Iransfonnation of the hexa- and other higher brominated PBBs in the atmosphere due to reaction with OH radicals may not be irrportant. 

Polybrominated Diphenyl Ethers. In 1999, the concentration of PBDEs in Lake Ontario surface waters ranged between 4 and 13 pg/L with 90% in the dissolved phase (Luckey et al. 2001). BDE47 and BDE-99 were the most abundant congeners, together making up >70% of the total PBDEs. No other information was located about the concentrations of PBDEs in water. 

PBDEs = polybrominated diphenyl ethers SIM = secondary ion measurement SPE = solid phase extraction... 

Polybrominated Diphenyl Ethers. Like PCBs, air samples containing PBDEs are usually collected by pumping air through a sampler containing a glass fiber filter and adsorbent trap to separate the particle bound and vapor phase fractions, respectively (Dobber et al 2000a Hillery et al 1997). The filters and adsorbants are then Soxhlet extracted with acetone/hexane, and the extracts are cleaned-up and analyzed by high resolution GC techniques. 

Shoeib, M., Harner, T., Ikonomou, M. and Kannan, K. (2004) Indoor and Outdoor Air Concentrations and phase partitioning of perfluoroalkyl sulfonamides and polybrominated diphenyl ethers. Environmental Science and Technology, 38, 1313-20. 

The main types of brominated flame retardants (BFRs) are polybromin-ated biphenyls (PBBs), PBDEs, and tetrabromobisphenol A (TBBPA). PBDEs have replaced PBBs, which are the first brominated organic compounds to be used as flame retardants and were phased out because of environmental issues, but are now being replaced by TBBPA (Renner, 2000). The global consumption of BFRs is estimated to be 203425 tons in 1999 with PBDEs accounting for 33% (Fig. 2.10). Deca-BDEs, 82% of total PBDEs, are the most widely used product. Domestic BFR consumption in South Korea in 2002 was 49050 tons, of which 25% (i.e., 12408 tons) was PBDEs with deca-BDE accounting for 12324 tons and penta- and octa-BDEs accounting for 84 tons (KMOE, 2005c). Imported amounts of each product in 2003 showed a similar distribution to the consumption estimated in 2002 (Fig. 2.10). In BFR market of Western Europe, consumption of PBDEs has declined from 26% in 1996 to 11% in 1998 (DEPA, 1999). Penta-BDEs product has been restricted for over one decade and is now banned within Europe. Furthermore, there has... 

Zhou, Y.-Y. The use of cooper(II) isonicotinate-based micro-solid-phase extraction for the analysis of polybrominated diphenyl ethers in soils. Anal. Chim. Acta 747, 36 (2012)... 

Other abbreviations. MAX, mixed anion exchange MIP, molecularly imprinted polymer PBB, polybrominated biphenyl PBDE, polybrominated diphenyl ether PBP, polybromianted phenols PDMS, polymethyldisiloxane PS-DVB, polystyrene-divinyl benzene SAX, stron anion exchange SPE, solid-phase extraction TBBPA, tetrabromobisphenol A TCBPA, tetrachlorobisphenol A. 

Subacute thyroiditis exhibits easily recognizable clinical features. It is not a common cause of hypothyroidism in the elderly. Painless thyroiditis is also infrequent in aged people. These conditions may cause transient hyperthyroidism followed by a transient permanent thyroid hypofunction phase. Infiltrative diseases affecting the thyroid gland (Riedel s thyroiditis, hemochromatosis, scleroderma, leukemia, amyloidosis) and infections are rare causes of hypothyroidism at all ages. Toxic injury to the thyroid gland has been reported after exposure to polybrominated biphenyls and polychlorinated biphenyls (Roberts and Ladenson, 2004). 

Cetin B, Odabasi M (2008) Atmospheric concentrations and phase partitioning of polytaominated diphenyl ethers (PBDEs) in Izmir, Turkey. Chemosphere 71 1067-1078 Chen S-J, Hsieh L-T, Hwang P-S (1996) Concentration, phase distribution, and size distribution of atmospheric polychlorinated biphenyls measured in southern Taiwan. Environ Int 22 411-423 Chen L-G, Mai B-X, Bi X-H et al (2006) Concentration levels, compositional profiles, and gas-particle partitioning of polybrominated diphenyl ethers in the atmosphere of an urban city in South China Environ Sci Technol 40 1190-1196 Chuang JC, Mack GA, Kuhlman MR et al (1991) Polycyclic aromatic hydrocarbons and then-derivatives in indoor and outdoor air in an eight-home study. Atmos Environ B 25 369-380 Cotham WE, Bidleman TF (1995) Polycyclic aromatic hydrocarbons and polychlorinated biphenyls in air at an urban and a rural site near Lake Michigan. Environ Sci Technol 29 2782-2789... 

Hayakawa K, Takatsuki H, Watanabe I et al (2004) Polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) and monobromo-polychlori-nated dibenzo-p-dioxins/dibenzofurans (MoBPXDD/Fs) in the atmosphere and bulk deposition in Kyoto, Jrqian. Chemosphere 57 343-356 Hildemarm LM, Markowski GR, Jones MC et al (1991) Submicrometer aerosol mass distributions of emissions from boilers, fireplaces, automobiles, diesel trucks, and meatcooking operations. Aerosol Sci Technol 14 138-152 HlUery BR, Basu I, Sweet CW et al (1997) Temporal and spatial trends in a long-term study of gas-phase PCB eoncentrations near the Great Lakes. Environ Sci Technol 31 1811-1816 Hites RA (2004) Polybrominated diphenyl ethers in the environment and in people a metaanalysis of eoneentrations. Environ Sci Technol 38 945-956... 

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