Influence of Hydrodynamic Disintegration on the Release of Organic and Nutrient Compounds From Activated Sludge     

《洁净——土壤、空气、水》2017,45(11)

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海水中大分子有机质对铂族元素的吸附动力学研究     

刘凯  高学鲁  邢前国  陈夫山 《海洋学报(英文版)》2019,38(8):8-16

Adsorption kinetics of the interaction between Pt, Pd and Rh(defined here as platinum group elements, PGEs)ions and macromolecular organic compounds(MOCs, 10 kDa), including humic acid, carrageenan and bovine serum albumin, and different cutoff fractions of natural organic matter(1 kDa and 3 kDa) obtained from seawater using centrifugal ultrafiltration devices were investigated. For a given element, all the adsorption kinetics did not reach equilibrium except the interaction between Pt and 1 kDa cutoff, and between Pd and humic acid.For all the tested MOCs, the adsorption kinetics could be divided into two stages, a rapid adsorption process in the first 8 h and the desorption stage after the first 8 h until the equilibrium. The change trend of partition coefficient(log_(10)K_d) values with experiment time was consistent with that of the kinetic curves. However, in the interaction between PGE ions and natural dissolved organic matter(NDOM), an obvious difference in the change trends of log_(10)K_d and kinetic curves was observed. It indicated that the partition behavior of PGE ions interacting with NDOM in seawater was a combined effect of different organic constituents. The adsorption and log_(10)K_d of PGEs in the 1 kDa NDOM fraction were higher and more stable than those in the 3 kDa NDOM fraction. The results also indicated that the 1–3 kDa NDOM may dominate the interaction between PGEs ions and NDOM. Moreover, no kinetic model could perfectly simulate the adsorption process. It indicated that the colloidal struction and morphology of MOCs or NDOM in seawater might be inhomogeneous. Hence, the interaction between PGE ions and organic matter in seawater was a complicated process and needs further research.  相似文献   

季铵盐类化合物灭杀赤潮异弯藻的实验研究   总被引：29，自引：2，他引：29       下载免费PDF全文

曹西华  俞志明 《海洋与湖沼》2003,34(2):201-207

通过对几种不同结构的季铵盐类化合物对赤潮异弯藻的去除效率进行比较，发现具有一定结构的季铵盐类化合物对该种藻具有较强的灭杀去除效果；在相同用量（质量）下，含有一个长碳链的季铵盐化合物的灭杀效果明显高于含有双长链的季铵盐化合物。同时，通过测定十六烷基三甲基溴化铵作用下的赤潮异弯藻的叶绿素含量变化和光合作用强度，并借用透射电镜研究了受肋迫藻细胞的亚显微结构，从而分析了季铵盐类化合物灭杀赤潮生物的原理：季铵盐对赤潮异弯藻的“毒性“主要是由于其强表面活性，易于吸附在藻细胞的磷脂双分子膜结构的表面，从而引起膜结构的破坏和功能的丧失，进而导致细胞死亡。  相似文献   

环保型无铬盐木素类新化灌材料的探索研究     

杜嘉鸿赵顺生  陈兰云王杰 《探矿工程》2006,33(11):5-8

分析丁木素类化灌材料的胶凝机理，并对硫木素、糠脲木素、酚醛木素等化灌材料进行了探索研究，给出了这几种浆材的配方、抗压强度、胶凝时间等参数，并分析了其影响因素。  相似文献   

Specific accumulation and temporal trends of organochlorine contaminants in Dall's porpoises (Phocoenoides dalli) from Japanese coastal waters     

Kajiwara N  Watanabe M  Tanabe S  Nakamatsu K  Amano M  Miyazaki N 《Marine pollution bulletin》2002,44(10):1089-1099

Organochlorine compounds (OCs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane related compounds, hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), tris(4-chlorophenyl) methane (TCPMe) and tris(4-chlorophenyl) methanol were determined in the blubber of Dall's porpoises (Phocoenoides dalli) collected from Japanese coastal waters in 1998/1999. Among OCs analyzed, PCBs were the predominant contaminants with concentrations ranging from 1.5 to 39 microg/g on a wet weight basis. OCs concentrations were relatively low and less variable in mature females possibly due to the lactational excretion from their bodies, while in males the concentrations were increased with body length. Concentrations and compositions of DDTs and HCHs showed significant differences between the truei-type population off the Pacific coast of northern Japan and dalli-type from the Sea of Japan/Okhotsk, suggesting its usefulness to discriminate different populations. OCs levels detected in truei-type porpoises collected in 1998/1999 were lower than those collected in 1984, except TCPMe. On the other hand, except DDTs, the residue levels of other organochlorines in dalli-type porpoises showed no significant decrease since 1984.  相似文献   

Toxicological and chemical assessment of ordinance compounds in marine sediments and porewaters     

Nipper M  Carr RS  Biedenbach JM  Hooten RL  Miller K 《Marine pollution bulletin》2002,44(8):789-806

Toxicological and chemical studies were performed with a silty and a sandy marine sediment spiked with 2,6-dinitrotoluene (2,6-DNT), 2,4,6-trinitrophenylmethylnitramine (tetryl), or 2,4,6-trinitrophenol (picric acid). Whole sediment toxicity was analyzed by the 10-day survival test with the amphipod Ampelisca abdita, and porewater toxicity tests assessed macro-algae (Ulva fasciata) zoospore germination and germling growth, sea urchin (Arbacia punctulata) embryological development, and polychaete (Dinophilus gyrociliatus) survival and reproduction. Whole sediments spiked with 2,6-DNT were not toxic to amphipods. The fine-grained sediment spiked with tetryl was also not acutely toxic. The tetryl and picric acid LC50 values in the sandy sediment were 3.24 and 144 mg/kg dry weight, respectively. The fine-grained sediment spiked with picric acid generated a U-shaped concentration-response curve in the amphipod test, with increased survival both in the lowest and highest concentration. Grain-size distribution and organic carbon content strongly influenced the behavior of ordnance compounds in spiked sediments. Very low concentrations were measured in some of the treatments and irreversible binding and biodegradation are suggested as the processes responsible for the low measurements. Porewater toxicity varied with its sedimentary origin and with ordnance compound. The sea urchin embryological development test tended to be the least sensitive. Tetryl was the most toxic chemical in all porewater tests, and picric acid the least toxic. Samples spiked with 2,6-DNT contained a degradation product identified as 2-methyl-3-nitroaniline (also known as 2-amino-6-nitrotoluene), and unidentified peaks, possibly degradation products, were also seen in some of the picric acid- and tetryl-spiked samples. Degradation products may have played a role in observed toxicity.  相似文献   

Contribution of Secondary VOC to the Composition of Aqueous Atmospheric Particles: A Modeling Approach     

Bernard Aumont  Sasha Madronich  Isabelle Bey  Geoffrey S. Tyndall 《Journal of Atmospheric Chemistry》2000,35(1):59-75

Measurements show that 20–60% of the carbon mass present in fine atmospheric particulate matter consists of water soluble organic compounds (WSOC). However, only 5–20% of this WSOC has been identified, mainly as dicarboxylic acids. Because of their high solubility in water, multifunctional secondary compounds derived from the gas-phase oxidation of volatile organic compounds (VOC) are suspected to be key contributors to the WSOC. To test this assumption, an estimate of aqueous uptake of secondary VOC was included in a highly detailed gas-phase mechanism which treats explicitly the formation of the secondary VOC from a set of representative primary species. Simulations were conducted for 2 scenarios, representing typical rural and urban areas. It was observed that the uptake of secondary VOC can lead to WSOC mass concentrations in the range of a few C m^–3, in fairly good agreement with typical WSOC mass concentrations measured. Speciation of WSOC was found to be mainly as tri- or higher multifunctional hydroxy-carbonyl species and hydroxy-hydroperoxide-carbonyl species, in urban and rural environments, respectively. However, it was also found that taking into account only the absorption of secondary VOC does not bring the carboxylic acids mass concentration in agreement with measurements. An attempt was made to explain this discrepancy by introducing chemistry occurring within deliquescent aerosols.  相似文献   

An analytical model for vapor‐phase volatile organic compound diffusion through landfill composite covers          下载免费PDF全文

Haijian Xie  Huaxiang Yan  Hywel R. Thomas  Shijin Feng  Qihua Ran  Peixiong Chen 《国际地质力学数值与分析法杂志》2016,40(13):1827-1843

One‐dimensional mathematical models for vapor‐phase volatile organic compound (VOC) diffusion through composite cover barriers are presented. An analytical solution to the model was obtained by the method of separation of variables. The results obtained by the proposed solution agree well with those obtained by a numerical analysis. Based on the proposed analytical model, the VOC breakthrough curves of five different composite covers are compared. The effects of degree of saturation of geosynthetic clay liner (GCL) or compacted clay liner (CCL) on VOC migration in the composite covers are then presented. Results show that the composite cover barriers provide much better diffusion barriers for VOC than the single CCL. The top surface steady‐state flux for a composite barrier, consisting of a 1.5 mm geomembrane (GM) and a 20 cm CCL, can be 8.3 times lower than that for a 30 cm CCL. The surface steady‐state flux for the case with (1.5 mm GM + 6 mm GCL) was found to be 2.3 times lower than that for the case with (1.5 mm GM + 20 cm CCL). The degree of saturation S_r of the CCL has a great influence on VOC migration in composite covers when S_r is larger than 0.5. The steady‐state flux at the surface of GM for the case with S_r = 0.7 can be 1.8 times lower than that for the case with S_r = 0.2. The proposed analytical model is relatively simple and can be used for verification of complicated numerical models, analysis of experimental data and performance assessment of composite cover barriers. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Trends of persistent organic pollutants in the suspended matter of the River Rhine     

Thorsten Pohlert  Gudrun Hillebrand  Vera Breitung 《水文研究》2011,25(24):3803-3817

Recently amended European (EU) water policies call for an adequate monitoring of the chemical status of sediments and suspended matter (SM) in rivers. In this study, we focus on long‐term time series of particle‐bound hexachlorobenzene (HCB) and selected polychlorinated biphenyls (PCB‐138 and PCB‐153) that were monitored biweekly to monthly at eight stations in the River Rhine catchment. Our aims are (1) to detect trends in the concentration series HCB, PCB‐138 and PCB‐153, (2) to estimate the uncertainty of loads caused by SM collection techniques and load calculation procedures and (3) to detect trends in the subsequently calculated annual load series. HCB concentration in the SM for the period 1995–2008 significantly (p < 0·01) decreased at six of the eight monitoring stations. Decreasing PCB‐138 and PCB‐153 concentrations are significant at six of the eight and seven of the eight monitoring stations, respectively. A two‐way analysis of variance (ANOVA) that tested the effect of two collection techniques and four load calculation procedures on annual loads indicates homogeneity of the methods at four of the five monitoring stations. At Weil, only the loads of HCB, PCB‐138 and PCB‐153 are significantly affected by the collection technique. The trend analysis of an extended series (1985–2007) of annual HCB loads at Koblenz showed a significant decrease from about 110 kg year^?1 to about 15–23 kg year^?1; however, in the shorter period (1995–2007) only at two of the eight monitoring stations decreasing trends of annual contaminant load could be detected. We conclude that any of the tested load calculation procedures can be applied, as loads do no differ systematically. Although a high uncertainty in load estimation exists (e.g. maximum percentage error of E = [18·1, 122·5]% for HCB), the monitoring programme at the Rhine is adequate for analysing the long‐term chemical status of SM. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Characterization and source apportionment of volatile organic compounds in urban and suburban Tianjin,China   总被引：1，自引：0，他引：1  

Meng Han  Xueqiang Lu  Chunsheng Zhao  Liang Ran  Suqin Han 《大气科学进展》2015,32(3):439-444

Tianjin is the third largest megacity and the fastest growth area in China, and consequently faces the problems of surface ozone and haze episodes. This study measures and characterizes volatile organic compounds(VOCs), which are ozone precursors, to identify their possible sources and evaluate their contribution to ozone formation in urban and suburban Tianjin,China during the Ha Chi(Haze in China) summer campaign in 2009. A total of 107 species of ambient VOCs were detected,and the average concentrations of VOCs at urban and suburban sites were 92 and 174 ppbv, respectively. Of those, 51 species of VOCs were extracted to analyze the possible VOC sources using positive matrix factorization. The identified sources of VOCs were significantly related to vehicular activities, which specifically contributed 60% to urban and 42% to suburban VOCs loadings in Tianjin. Industrial emission was the second most prominent source of ambient VOCs in both urban and suburban areas, although the contribution of industry in the suburban area(36%) was much higher than that at the urban area(16%). We conclude that controlling vehicle emissions should be a top priority for VOC reduction, and that fast industrialization and urbanization causes air pollution to be more complex due to the combined emission of VOCs from industry and daily life, especially in suburban areas.  相似文献