Photochemical generation rates of hydroxyl radical in aqueous solutions containing Fe(III)-hydroxy complex

The rates of photochemical generation of hydroxyl radical at 313 nm in aqueous solutions containing ferric ion at acidic pH were measured by the competitive kinetic method using 2-chlorophenol as a test compound and 1-octanol as a radical scavenger. The quantum yield of hydroxyl radical generation calculated from the rates was about 0.02. From the results, it was suggested that this system could be used as a method of wastewater treatment.     

Aluminum position in Rb-feldspar as determined by X-ray photoelectron spectroscopy

Al/Si configurations in some natural and synthetic Rb-feldspars have been examined carefully by EMPA and XPS analyses. Our results indicate that a small amount of H₂O and excess Si and Al are incorporated in hydrothermally synthesized Rb-feldspar. The quantities of excess Al are 0.056 atoms per formula unit and are negatively correlated with those of the Rb, suggesting the presence of excess Al occupying non-tetrahedral sites in feldspar structures. This leads to incorporation of Al(Al₃Si)O₈ endmember into Rb-feldspars, estimated as one appropriate endmember indication for unusual chemistry of feldspars. In addition, Si2p, Al2p and O1s XPS signals of Rb-feldspars shift drastically toward the higher energy side than those of any natural feldspars. These provide conclusive evidence not only for existence of perceptible excess Si and Al, but also for Al at both extra-framework and tetrahedral sites in feldspar structures.     

Modification of carbon-coated TiO2 by iron to increase adsorptivity and photoactivity for phenol

Carbon-coated TiO(2) modified by iron, were prepared from TiO(2) of anatase structure and PET modified by FeC(2)O(4). Catalysts were prepared by mixing powders of TiO(2) and modified PET and heating at different temperatures, from 400 to 800 degrees C under flow of Ar gas. High adsorption of phenol was observed on the catalyst heated at 400 degrees C, confirmed by FT-IR analysis. On this catalyst, fast rate of phenol decomposition was achieved by addition of small amount of H(2)O(2) to the reaction mixture. Phenol decomposition proceeded mainly through the direct oxidation of phenol species adsorbed on the catalyst surface due to the photo-Fenton reaction. Iron-modified carbon-coated TiO(2) catalysts heated at 500-800 degrees C showed almost no phenol adsorption or oxidation.     

Vertical distribution,population structure and lifecycle of<Emphasis Type="Italic"> Eucalanus bungii</Emphasis> (Copepoda: Calanoida) in the Oyashio region,with notes on its regional variations

Vertical distribution and population structure of Eucalanus bungii were investigated at site H in the Oyashio region (western subarctic Pacific) from September 1996 through October 1997 to evaluate the species lifecycle pattern and associated ontogenetic vertical migration. Additional temporary samplings were also made at several stations covering the entire subarctic Pacific, Okhotsk Sea and Japan Sea, as a basis for regional comparison of lifecycle features of this species. At site H, a marked phytoplankton bloom occurred from mid-March to June, and E. bungii spawned in April/May in the surface layer. Resulting nauplii and copepodite stage 1 (C1) formed a prominent abundance peak in early June. The C1 developed and reached C5 by August. The development of nauplii through C4 occurred in the surface layer. From August onwards, C5 and a small fraction of C3–C4 sank gradually deeper, and entered diapause to overwinter at >500 m depth. The C5 molted to C6 males and females in February and March, respectively. The C6 males and females mated at 250–500 m depth, and only mated C6 females ascended to the surface layer in April for spawning. Judging from the size of lipid droplets in the body, the C3–C5 specimens deposited lipids in the body through the phytoplankton bloom period, and the lipids were consumed gradually during overwintering. Taking account of sampling season, temporal changes in population structure, and vertical distribution, the data collected from the western subarctic Pacific and Okhotsk Sea are consistent with a 1-year lifecycle for the site H population, while the data from the central and eastern subarctic Pacific were consistent with a 2-year lifecycle. The populations from the southern and southeastern Japan Sea did not fit the features of either lifecycle scenario, and because of their very small population size it is suggested that they originated from the northern Japan Sea. Regional comparison of the prosome length of C6 females, including those in the Bering Sea, indicated significantly larger specimens from the Japan Sea and Okhotsk Sea, and smaller specimens in the eastern subarctic Pacific, as compared with those in the western subarctic Pacific (including site H) and Bering Sea. A possible overwintering mechanism of E. bungii is discussed.Communicated by O. Kinne, Oldendorf/Luhe     

Spawning migration and returning behavior of white-streaked grouper Epinephelus ongus determined by acoustic telemetry

White-streaked grouper (Epinephelus ongus) is an important fishery target that forms fish spawning aggregations (FSAs) at specific spawning grounds. The aims of the present study were to investigate migration behavior and returning behavior in terms of FSA using acoustic telemetry. Among the 30 specimens tracked, three types of movement pattern were observed: type 1, high site fidelity at the release area before the spawning period, migration to the spawning ground during the spawning period and return to the release area just after the spawning period (17 specimens); type 2, high site fidelity at the release area, disappearance from the area during the spawning period but was not detected at the spawning ground and return to the release area (8 specimens); and type 3, high site fidelity at the release area was observed before, during and after the spawning period (5 specimens). For the 17 specimens that were categorized into type 1, the dates of departure from their release area and the dates of return to the release area of males were, respectively, significantly earlier and later than those of females. The duration between the departure date and the return date (“duration away”) of males was significantly longer than that of females. The duration away tended to be positively related to the condition factor. All 25 specimens that were categorized as type 1 and type 2 showed returning behaviors to the release area.     

Estimating the amount of WEEE generated in South Korea by using the population balance model

We estimated the amount of waste electrical and electronic equipment (WEEE) generated in South Korea by using the population balance model (PBM) based on a lifespan distribution analysis. This is the first study to apply PBM to estimate WEEE generation in South Korea. The lifespan distribution analysis of electrical and electronic equipment (EEE) was based on the results of a questionnaire survey of 1000 households, which were analyzed with the Weibull distribution. As a result, we could estimate the domestic service lifespan and lifespan distribution shape parameter for eight selected products. Using the lifespan distribution analysis and other data, such as the shipment volume and the number of products owned by households, we estimated the amount of WEEE generated for the eight selected items from 2000 to 2020. We found that 1.2 million air conditioners, 2.5 million televisions, 1.3 million microwave ovens, 1.2 million kimchi refrigerators, 17.0 million mobile phones, 1.7 million refrigerators, 2.0 million vacuum cleaners, and 1.4 million washing machines were generated as WEEE in 2010. We also compared our WEEE estimates with the number of items collected through the official WEEE recycling program from 2003 to 2009 and found that in 2009 washing machines had the highest collection rate (28%) and air conditioners had the lowest rate (7%).     

Dependence of photocatalytic activity of anatase powders on their crystallinity

Structural changes in anatase phase in four TiO(2) photocatalysts with annealing at high temperatures were followed by evaluating crystallite size and lattice strain of anatase phase separately and measuring the content of anatase. The rate constant k for the decomposition of methylene blue in its aqueous solution under UV irradiation was determined as a measure of photocatalytic activity. Marked dependences in crystallinity improvement, i.e., the growth of crystallite and the decrease in lattice strain, and in phase transformation from anatase to rutile phases of TiO(2) on annealing temperature was observed above 500 degrees C, depending on starting photocatalysts used. The phase transformation to rutile started after reaching of crystallite size to about 32 nm and of lattice strain to about 0.5 x 10(-3). Rate constant k was found to depend on both crystallite size and lattice strain of anatase; it increased with increasing crystallite size up to about 32 nm and decreasing lattice strain down to about 0.5 x 10(-3). Further increase in crystallite size and decrease in lattice strain induced the decrease in rate constant k, mainly due to the partial transformation of anatase to rutile. The present results showed that the activity of the photocatalysts was possible to be improved by annealing at a high temperature, by selecting an optimal condition of annealing for getting a high crystallinity in anatase phase and no phase transformation to rutile phase.     

Distribution and temporal changes of lead in the surface seawater in the western Pacific and adjacent seas derived from coral skeletons

We determined Pb contents together with Pb isotopic compositions in coral skeletons (Porites spp.) collected from the western Pacific and adjacent seas to examine distribution of Pb in sea surfaces. Temporal records of Pb were also investigated using coral skeletons from Hainan and Ogasawara Island, located in China and Japan, respectively. The spatial distribution of Pb showed a clear dilution pattern of Pb from Asian continent to the open ocean. Also the similar trend was found in the Java Sea from Jakarta to the offshore. In addition to the spatial distribution, Pb contents in Ogasawara coral have gradually increased during last 108 years. It may be attributed to Pb emission mainly from industrial activities in Asian countries. Hainan coral, which provided 10 years record of Pb, showed a remarkable decline around 1997 probably due to the partial introduction of unleaded gasoline in China.     

Pathways and Kinetics on Photocatalytic Destruction of Aqueous Phenol

In this study, the TiO₂ photocatalytic decomposition process of aqueous phenol was investigated. The intermediate products generated in the elementary reaction steps in the mineralization process were experimentally identified as hydroquinone, catechol and hydroxyhydroquinone. The concentration variations of these intermediate products with time passage were traced by high performance liquid chromatograph. The pathways of the decomposition process were given. Based on Langmuir isothermal theory and Langmuir-Hinshelwood mechanism, the multi-compounds competition kinetic model was established. In this model, the observed time-dependent concentrations of phenol and the intermediate products were simulated.     

Secondary materials transfer from Japan to China: destination analysis

China has been the largest importer of secondary materials for recycling from Japan during the past decade. In this study, we analyzed the transfer of major secondary materials (plastic, steel, copper, and aluminum scrap) from Japan to China. We identified specific destinations for secondary materials, and the characteristics of secondary materials transferred to China. The major destination for the transfer of secondary materials to China is Guangdong province and part of the Huadong area (Shanghai, Zhejiang, and Jiangsu). Most scrap metal imported into China is of low quality. The destinations of most high-quality nonferrous scrap, imported as processed goods on consignment or through the transit improvement trade, are the northeast border provinces, especially Xinjiang Uighur province. The coefficients of specialization for Chinese cities were different from those for the provinces. Guangdong shows an average recycling structure for China. The structure gradually changes from south to north.