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duanlin_nk银虫 (小有名气)
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2007-4-26 EST最新文章和摘要
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1、Characterization of Zinc, Lead, and Cadmium in Mine Waste: Implications for Transport, Exposure, and Bioavailability Laurel A. Schaider,* David B. Senn, Daniel J. Brabander, Kathleen D. McCarthy, and James P. Shine Department of Environmental Health, Harvard School of Public Health, 401 Park Drive, Boston, Massachusetts 02215, and Department of Geosciences, Wellesley College, 106 Central Street, Wellesley, Massachusetts 02481 Received for review November 10, 2006 Revised manuscript received March 8, 2007 Accepted March 12, 2007 Abstract: We characterized the lability and bioaccessibility of Zn, Pb, and Cd in size-fractionated mine waste at the Tar Creek Superfund Site (Oklahoma) to assess the potential for metal transport, exposure, and subsequent bioavailability. Bulk mine waste samples contained elevated Zn (9100 ± 2500 ppm), Pb (650 ± 360 ppm), and Cd (42 ± 10 ppm), while particles with the greatest potential for wind-borne transport and inhalation (<10 m) contained substantially higher concentrations, up to 220 000 ppm Zn, 16 000 ppm Pb, and 530 ppm Cd in particles <1 m. Although the mined ore at Tar Creek primarily consisted of refractory metal sulfides with low bioavailability, sequential extractions and physiologically based extractions indicate that physical and chemical weathering have shifted metals into relatively labile and bioaccessible mineral phases. In <37 m mine waste particles, 50-65% of Zn, Pb, and Cd were present in the "exchangeable" and "carbonate" sequential extraction fractions, and 60-80% of Zn, Pb, and Cd were mobilized in synthetic gastric fluid, while ZnS and PbS exhibited minimal solubility in these solutions. Our results demonstrate the importance of site-specific characterization of size-fractionated contemporary mine waste when assessing the lability and bioavailability of metals at mine-waste impacted sites. ************************************************************ 2、Removal of Lipophilic Extractives from Paper Pulp by Laccase and Lignin-Derived Phenols as Natural Mediators Ana Gutiérrez,* Jorge Rencoret, David Ibarra, Setefilla Molina, Susana Camarero, Javier Romero, José C. Del Río, and ngel T. Martínez Instituto de Recursos Naturales y Agrobiología de Sevilla, CSIC, PO Box 1052, E-41080 Seville, Spain, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain, and Centro de Investigación y Tecnología, ENCE, Carretera de Campañó, Ribeiro Vao, E-36157 Pontevedra, Spain Received for review November 14, 2006 Revised manuscript received March 2, 2007 Accepted March 26, 2007 Abstract: In this paper, we show for the first time that lignin-derived phenols can act as laccase mediators for the removal of lipophilic compounds from paper pulp. These natural mediators represent an alternative to synthetic mediators, such as 1-hydroxybenzotriazole (HBT), that cause some economic and environmental concerns. Unbleached kraft pulp from eucalypt wood, which contained free and conjugated sterols responsible for pitch deposition in the manufacture of totally chlorine free paper, was treated with a fungal laccase in the presence of syringaldehyde, acetosyringone, and p-coumaric acid as mediators. The composition of lipophilic extractives in the pulps after the enzymatic treatment followed by a hydrogen peroxide stage was analyzed by gas chromatography and gas chromatography/mass spectrometry. The enzymatic treatment using syringaldehyde as laccase mediator caused the highest removal (over 90%) of free and conjugated sitosterol, similar to that attained with HBT, followed by acetosyringone (over 60% removal), whereas p-coumaric acid was barely effective. Moreover, recalcitrant oxidized steroids surviving laccase-HBT treatment could be removed when using these natural mediators. Pulp brightness was also improved (from 57% to 66% ISO brightness) by the laccase treatment in the presence of the above phenols followed by the peroxide stage due to the simultaneous removal of lignin. ************************************************************ 3、A Comparative Life Cycle Assessment of Petroleum and Soybean-Based Lubricants Shelie A. Miller,* Amy E. Landis, Thomas L. Theis, and Ronald A. Reich School of the Environment, Environmental Engineering and Science, Clemson University, Clemson, South Carolina, Institute for Environmental Science and Policy, University of Illinois at Chicago, 2121 W. Taylor Street, Chicago, Illinois 60612, and Alcoa Technical Center, Alcoa, Pennsylvania Received for review November 14, 2006 Accepted March 14, 2007 Abstract: A comparative life cycle assessment examining soybean and petroleum-based lubricants is compiled using Monte Carlo analysis to assess system variability. Experimental data obtained from an aluminum manufacturing facility indicate significantly less soybean lubricant is required to achieve similar or superior performance. With improved performance and a lower use rate, a transition to soybean oil results in lower aggregate impacts of acidification, smog formation, and human health from criteria pollutants. Regardless of quantity consumed, soybean-based lubricants exhibit significant climate change and fossil fuel use benefits; however, eutrophication impacts are much greater due to non-point nutrient emissions. Fundamental tradeoffs in the carbon and nitrogen cycles are addressed in the analysis, demonstrating that a transition to soybean oil may result in climate change benefits at the expense of regional water quality. ************************************************************ 4、Time-Weighted Average Water Sampling in Lake Ontario with Solid-Phase Microextraction Passive Samplers Gangfeng Ouyang, Wennan Zhao, Leslie Bragg, Zhipei Qin, Mehran Alaee, and Janusz Pawliszyn* School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, China, Department of Chemistry, University of Waterloo, Ontario, N2L 3G1, Canada, and Water Science and Technology Directorate, Environment Canada, Burlington, Ontario, L7R 4A6, Canada Received for review November 3, 2006 Revised manuscript received February 14, 2007 Accepted March 21, 2007 Abstract: In this study, three types of solid-phase microextraction (SPME) passive samplers, including a fiber-retracted device, a polydimethylsiloxane (PDMS)-rod and a PDMS-membrane, were evaluated to determine the time weighted average (TWA) concentrations of polycyclic aromatic hydrocarbons (PAHs) in Hamilton Harbor (the western tip of Lake Ontario, ON, Canada). Field trials demonstrated that these types of SPME samplers are suitable for the long-term monitoring of organic pollutants in water. These samplers possess all of the advantages of SPME: they are solvent-free, sampling, extraction and concentration are combined into one step, and they can be directly injected into a gas chromatograph (GC) for analysis without further treatment. These samplers also address the additional needs of a passive sampling technique: they are economical, easy to deploy, and the TWA concentrations of target analytes can be obtained with one sampler. Moreover, the mass uptake of these samplers is independent of the face velocity, or the effect can be calibrated, which is desirable for long-term field sampling, especially when the convection conditions of the sampling environment are difficult to measure and calibrate. Among the three types of SPME samplers that were tested, the PDMS-membrane possesses the highest surface-to-volume ratio, which results in the highest sensitivity and mass uptake and the lowest detection level. ************************************************************ 5、Iron Optimization for Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon Scott G. Huling,* Patrick K. Jones, and Tony R. Lee Office of Research and Development, National Risk Management Research Laboratory, U.S. Environmental Protection Agency, P.O. Box 1198, Ada, Oklahoma 74820 Received for review November 6, 2006 Revised manuscript received March 15, 2007 Accepted March 16, 2007 Abstract: Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was accomplished through the addition of iron (Fe) and hydrogen peroxide (H2O2) (15.9 g/L; pH 3). The Fe concentration in GAC was incrementally varied (1020-25 660 mg/kg) by the addition of increasing concentrations of Fe solution (FeSO4·7H2O). MTBE degradation in Fe-amended GAC increased by an order of magnitude over Fe-unamended GAC and H2O2 reaction was predominantly (99%) attributed to GAC-bound Fe within the porous structure of the GAC. Imaging and microanalysis of GAC particles indicated limited penetration of Fe into GAC. The optimal Fe concentration was 6710 mg/kg (1020 mg/kg background; 5690 mg/kg amended Fe) and resulted in the greatest MTBE removal and maximum Fe loading oxidation efficiency (MTBE oxidized (g)/Fe loaded to GAC(mg/Kg)). At lower Fe concentrations, the H2O2 reaction was Fe limited. At higher Fe concentrations, the H2O2 reaction was not entirely Fe limited, and reductions in GAC surface area, GAC pore volume, MTBE adsorption, and Fe loading oxidation efficiency were measured. Results are consistent with nonuniform distribution of Fe, pore blockage in H2O2 transport, unavailable Fe, and limitations in H2O2 diffusive transport, and emphasize the importance of optimal Fe loading. ************************************************************ 6、Characterization of Cake Layer in Submerged Membrane Bioreactor Fangang Meng, Hanmin Zhang,* Fenglin Yang, and Lifen Liu School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China Received for review September 15, 2006 Revised manuscript received January 29, 2007 Accepted January 31, 2007 Abstract: Cake layer formation on the membrane surface has been a major challenge in the operation of membrane bioreactors (MBRs). In this study, the cake layer formation mechanism in an MBR used for synthetic wastewater treatment was investigated. The major components of cake layer were systematically examined by particle size analyzer (PSA), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray fluorescence (XRF), energy-diffusive X-ray analyzer (EDX), and Fourier transform infrared (FTIR) spectroscopy. The results indicate that the small particles in sludge suspension had a strong deposit tendency on the membrane surface. The SEM and CLSM analysis exhibited that bacterial clusters and polysaccharides were significant contributors to membrane fouling. The main components of biopolymers were identified as proteins and polysaccharide materials by the FTIR. The examination by EDX and XRF demonstrated that Mg, Al, Ca, Si, and Fe were the major inorganic elements in fouling cake. Furthermore, the results suggest that bridging between deposited biopolymers and inorganic compounds could enhance the compactness of fouling layer. During the operation of MBRs, the biopolymers and inorganic elements in the bioreactor should be controlled to minimize membrane fouling. ************************************************************ 7、Sustainable Use of Biofuel by Recycling Ash to Forests: Treatment of Biofuel Ash Maryam Mahmoudkhani, Tobias Richards, and Hans Theliander* Forest Products and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden Received for review August 30, 2006 Revised manuscript received March 23, 2007 Accepted March 27, 2007 Abstract: The influence of treatment techniques on leaching properties of alkaline species from biofuel ash is investigated in this paper. Ash samples from combustion of biofuels in a circulating fluidized bed and grate-firing combustion plants are studied. The samples are treated using three different treatment techniques; self-hardening, thermal treatment, and hardening by the addition of binding materials. Nontreated and treated samples are evaluated for the leaching properties of the alkaline compounds and, furthermore, are characterized with respect to both physical and chemical characteristics. The results show the influence of treatment techniques on the physical structure and leaching characteristics of alkaline species. Results also indicate that ash samples show different behavior when treated with different methods, i.e., the influence of treatment technique on controlling the leaching properties is highly dependent on the initial chemical composition of ash. It was also found that there is an interaction between leaching of limited and easily soluble species, e.g., calcium and potassium leaching. Therefore, to control the leaching rate of alkaline species from ash, the characteristics that correlate the leaching properties of both easily and limited soluble species need to be adjusted. ************************************************************ 呵呵，抢某人先发！ |
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