Effect of polyethylene terephthalate (PET) on the pyrolysis of brominated flame retardant-containing high-impact polystyrene (HIPS-Br)

Pyrolysis of brominated flame retardant-containing high-impact polystyrene (HIPS-Br) was performed at 430°C in the presence of 0.1 wt% of polyethylene terephthalate (PET) in a Pyrex glass reactor. Two different types of brominated flame retardants (decabromodiphenyl ether and decabromodiphenyl ethane) with or without antimony trioxide (as synergist) 5 wt% were used. The presence of PET had a significant effect on the material balance, decreasing the gaseous product and increasing the residue. The type of flame retardant had no effect on the yield of liquid product; however, the presence of Sb resulted in a marked difference in the distribution of decomposition products. Analysis by a gas chromatograph equipped with a flame ionization detector showed that the hydrocarbons were distributed in the range n-C₇ to n-C₂₅ with major peaks at n-C₉ and n-C₁₇. The presence of PET increased the formation of brominated compounds by several times and affected both the type and quantity of polybrominated compounds. The liquid products obtained from the pyrolysis of HIPS-Br/PET have to be treated before they can be used     

Differences in the Spatial Variability Among CO2, CH4, and N2O Gas Fluxes from an Urban Forest Soil in Japan

The spatial variability of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) fluxes from forest soil with high nitrogen (N) deposition was investigated at a rolling hill region in Japan. Gas fluxes were measured on July 25th and December 5th, 2008 at 100 points within a 100 × 100 m grid. Slope direction and position influenced soil characteristics and site-specific emissions were found. The CO₂ flux showed no topological difference in July, but was significantly lower in December for north-slope with coniferous trees. Spatial dependency of CH₄ fluxes was stronger than that of CO₂ or N₂O and showed a significantly higher uptake in hill top, and emissions in the valley indicating strong influence of water status. N₂O fluxes showed no spatial dependency and exhibited high hot spots at different topology in July and December. The high N deposition led to high N₂O fluxes and emphasized the spatial variability.     

Co-processing of DVDs and CDs with vegetable cooking oil by thermal degradation

Waste DVDs and CDs were thermally degraded at 450°C by a semibatch process. In total, 40–50 wt% was converted into liquid product that consisted of phenol derivatives (∼75 wt%), bisphenol (∼10 wt%) and its derivatives, and small amounts of aromatic hydrocarbons such as benzene, toluene, ethylbenzene, dimethylbenzene, methylethylbenzene, diethylbenzene, and methylisopropyl benzene. Degradation of the polycarbonate support from DVDs and CDs was enhanced by coprocessing with vegetable cooking oil, the degradation of which gave a homologue series of hydrocarbons and organic acids with up to 25 and 18 atoms of carbon, respectively. Silver from the reflective coating on DVDs and CDs remained in the solid residue, its concentration increasing about 2.5 times compared to that of the original disks.     

The influence of environmental deterioration and network improvement on transport modal choice

We consider that transport modal choices are influenced by natural environmental change and transport network improvement. This paper examines how these impacts affect individuals’ decisions on selecting transport mode under an extension plan for the Osaka Monorail Loop-line. To estimate these impacts, we perform a Stated Choice (SC) experiment for collecting data in the neighborhood along the monorail's extended line. We estimate our model with the Heteroskedastic Extreme Value (HEV) specification in order to avoid the Independence of Irrelevant Alternatives (IIA) assumption in the Multinomial Logit (MNL) model. Both the results of full-sample and sub-sample data imply that residents prefer public transport modes (monorail or bus) to private cars when either the natural environment becomes worse or the transport network improves.     

Mechanism of Depolymerization Reaction of Polyethylene Terephthalate: Experimental and Theoretical Studies

The depolymerization reaction of polyethylene terephthalate (PET) was analyzed on the basis of both experimental data and numerical data obtained from quantum chemistry calculations. Various alcohols were used as solvents in the search for the reaction mechanism. The activation energy obtained from the optimized structures of the ground state and the transitional state was compared with our experimental data. Based on these comparisons, it was found that the formation of rings from alkoxyl groups and carbonyl carbon atoms at the transitional state is highly important when the ester bonds of PET are broken. Moreover, the most appropriate alcohol was suggested for the depolymerization reaction.     

Individual and simultaneous degradation of brominated high impact polystyrene and brominated acrylonitrile-butadiene-styrene and removal of heteroelements (Br,N, and O) from degradation oil by multiphase catalytic systems

Brominated high-impact polystyrene (HIPS-Br), which contained decabromodiphenyl ether flame retardant, and brominated acrylonitrile butadiene styrene (ABS-Br), which contained bromine-containing epoxy-type flame retardant, were degraded at 450°C individually and in a 1/1 mixture by a thermal and catalytic procedure using folded sheet mesoporous (FSM) and ZSM-5 zeolite in liquid phase contact mode. The two polymers produced similar degradation oils but at a higher yield for HIPS-Br. However, the composition and distribution of Br-, N-, and O-containing compounds depended on the type of flame retardant in HIPS-Br and ABS-Br. Multiphase catalytic systems consisting of FSM in liquid phase contact mode and various CaH-, FeO-, CoMo-, and NiMo-based catalysts, or combinations of these catalysts, in vapor phase contact mode were used to decrease the amount of heteroatoms (Br, N, and O) in the degradation oils. Each system gave particular results in terms of mass balance and concentrations of heteroatoms. A FSM (liquid phase contact)/CaHC (vapor phase contact) combination was the best catalytic system to remove Br-, N-, and O-containing compounds from degradation oils.     

Production and characterization of KOH-activated carbon derived from polychlorinated biphenyl residue generated by the sodium dispersion process

Polychlorinated biphenyl (PCB) residues from the sodium dispersion (SD) process were employed as the raw materials for the production of activated carbon using KOH activation. The pore properties, such as the specific surface area and pore size distribution, were characterized using the Barrett–Joyner–Halenda method and the Horvath–Kawazoe method based on the N₂ adsorption isotherm at 77 K. The activated carbon produced showed similar adsorption capacities and specific surface areas to the commercially available product. The effects of the activation conditions on the porosity of the activated carbon produced were studied. The most significant factor affecting the specific surface proved to be the activation temperature. The activated carbon produced from PCB residues from the high-temperature (423–443 K) SD process had a binary pore size distribution well developed in the 4 nm region and in the micropore region. The pore structure of the carbon produced from PCB residues from the low-temperature (333–393 K) SD process had a wide range of micropores and mesopores.     

Detailed PCB congener patterns in incinerator flue gas and commercial PCB formulations (Kanechlor)

In this study, we determined the detailed PCB congener patterns in flue gases from eight incinerators and four commercial PCB formulations (Kanechlors). About 160 PCB peaks were identified in samples using a DB-5 column and HRGC/HRMS. The concentration of incinerator stack emission gas ranged from 0.02 to 44 ngWHO-TEQ/Nm3. The ratios of dioxin-like PCBs in the total PCB concentration were from 3.4% to 25.7% and from 0.63% to 9.1% in stack emission gases and Kanechlor samples, respectively. The PCB congener profiles of Kanechlor samples were similar to those of previous studies. To determine characteristic congeners in flue gas and Kanechlor samples, principal component analysis (PCA) of the data was conducted using STATISTICA for Windows 5.0J (StatSoft, Inc.). As a result, we obtained four principal components (PCs) and accounted for 74% of the total variance. PC 1 was interpreted combustion, PC 2 and PC 3 were interpreted the difference in the number of substituted chlorines and, PC 4 could not be determined. Moreover, we obtained three groups according to the PCB congeners pattern among samples by PCA. These specific congeners that represent characteristics of each class were identified. These data will be useful for the source analysis of PCBs in the environment.     

Contamination by mercury and cadmium in the cetacean products from Japanese market

Cetaceans hunted coastally in Japan include several species of odontocete (dolphins, porpoises and beaked whales), and fresh and frozen red meat and blubber, as well as boiled internal organs, such as liver, lung, kidney and small intestine, are still sold for human consumption. Furthermore, red meat and blubber products originating from mysticete minke whales caught in the Antarctic and Northern Pacific are also sold for human consumption. We surveyed mercury and cadmium contamination levels in boiled liver, lung, kidney and red meat products being marketed in Japanese retail outlets. We also analyzed the DNA of these products to obtain information concerning gender and species. Total mercury (T-Hg) and methyl mercury (M-Hg) contamination levels in all the cetacean products were markedly higher in odontocete species than in mysticete species, and slightly higher in females than in males. T-Hg contamination in the organs was seen in the following order: boiled liver > boiled KIDNEY=boiled lung > red meat. In particular, T-Hg concentrations in the boiled liver were high enough to cause acute intoxication even from a single ingestion: the mean ±SD (range) of T-Hg was 388 ± 543 (0.12–1980) μg/wet g. In contrast, although M-Hg contamination in the liver was not markedly higher than that in other organs, M-Hg contamination was in the following order: boiled liver > odontocete red meat > boiled kidney > boiled lung. The contamination levels of T-Hg and M-Hg in odontocete red meat, the most popular whale product, were 8.94 ± 13.3 and 5.44 ± 5.72 μg/wet g, respectively. These averages exceeded the provisional permitted levels of T-Hg (0.4 μg/wet g) and M-Hg (0.3 μg/wet g) in marine foods set by the Japanese Ministry of Health, Labor and Welfare by 22 and 18 times, respectively, suggesting the possibility of chronic intoxication by T-Hg and M-Hg with frequent consumption of odontocete red meat. Cadmium contamination levels in boiled liver, kidney and lung were 8.59 ± 12.0, 10.4 ± 8.6 and 1.66 ± 1.27 (μg/wet g), respectively.     

Pre-copulatory sexual selection in the cigarette beetle Lasioderma serricorne

Traditional concepts of sexual selection and sexual conflict make different predictions about the costs and benefits to females of exposure to males with higher mating success. The traditional concepts of sexual selection assume that females benefit from their mate choices, whereas sexual conflict assumes that the females suffer greater costs by mating with males who have greater mating success and thus reduce their fitness. In order to understand how mate choice evolves, it is necessary to estimate the overall effect of mate choice on female fitness. However, relatively few studies have conducted that investigation. In this study, we investigated the direct and indirect effects of mating with attractive males on the fitness of females in the cigarette beetle Lasioderma serricorne. Mating with attractive males increased the number of female offspring but did not affect female longevity. Additionally, we found evidence that attractive males sire highly attractive sons. Thus, mating with an attractive male provides direct and indirect benefits but no fitness cost to female L. serricorne.