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Phosphate removal and recovery through crystallization of hydroxyapatite using xonotlite as seed crystal

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Journal of environmental sciences 2009年第5期21卷 575-580页

作者： CHEN Xuechu, KONG Hainan, WU Deyi, WANG Xinze, LIN Yongyong School of environmental science and Engineering, Shanghai Jiao Tong university, Shanghai 200240, China [a]School of environmental science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

Xonotlite was synthesized and tested for phosphate removal and recovery from synthetic solution in a batch mode. The effects of pH, initial calcium concentration, bicarbonate concentration on phosphate removal through crystallization were examined. The morphology and X-ray diffraction （XRD） pattern of xonotlite before and after crystallization confirmed the formation of crystalline hydroxyapatite. The results indicated that the crystallization product had a very high P content （〉 10%）, which is comparable to phosphate rock at the dosage of 50-200 mg xonotlite per liter, with a maximum P content of 16.7%. The kinetics of phosphate removal followed the second-order reaction equation. The phosphate removal ability increased with increasing pH. The precipitation of calcium phosphate took place when pH was higher than 7.2, whereas the crystallization occurred at pH 6.0. A high calcium concentration could promote the removal of phosphate via crystallization, while a high bicarbonate concentration also enhanced phosphate removal, through that the pH was increased and thus induced the precipitation process. When xonotlite was used to remove phosphate from wastewater, the removal efficiency could reach 91.3% after 24 h reaction, with removal capacity 137 mg/g. The results indicated that xonotlite might be used as an effective crystal seed for the removal and recovery of phosphate from aqueous solution.

关键词： phosphate recovery crystallization xonotlite

Estimating health damage cost from secondary sulfate particles—a case study of Hunan Province,China

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Journal of environmental sciences 2003年第5期15卷 611-617页

作者： HAO Ji ming, LI Ji, YE Xue mei, ZHU Tian le (Department of environmental science and Engineering, Tsinghua university, Beijing 100084, China. ) Department of environmental science and Engineering Tsinghua University Beijing 100084 China

China's coal dominated energy pattern has resulted in large amount of SO 2 emissions. Estimate of the sulfur related health damage cost is necessary to help perform systematic cost benefit analysis and set national energy and emissions control priorities. Current researches were confined to gaseous SO 2 in urban areas; however, secondary sulfate (SO 2- 4) particles can exert serious impact in a wider region. Based on the concept of “intake fraction', caLPUFF long range dispersion model and 180 sample emission sources, multiple regression equation was obtained with good correlation( r =0 85), which illustrates that populations were key parameters to determine intake fraction but source characteristics were insignificant. Based on the formula and the population distribution data, county level intake fractions were mapped for Hunan Province(range: 1 1×10 -6 -3 2×10 -6 ) of China. A combination of county level SO 2 emissions with the intake fractions yields a total 1 98 tons of sulfate(SO 2- 4) inhalation, and resulting total health damage cost to be 0 76(willingness to pay approach, WTP) or 0 16(human capital approach, HC) billion USD in 1997, about 2.1% or 0 45% of GDP in Hunan in 1997. Average health damage cost per ton of SO 2 emission is 930(WTP) or 200 USD(HC). The results demonstrated that more stringent regulation should be forced.

关键词： intake fraction health impact Hunan Province sulfate regression analysis

Cryopreservation of amphioxus (Branchiostoma belcheri) spermatozoa

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Acta Oceanologica Sinica 2009年第2期28卷 96-102页

作者： XU Yuyan ZHANG Shicui VERAPONG Vuthiphandchai SUBUNTITH Nimrat College of Food science and Engineering Ocean University of China Qingdao 266003 China College of Marine Biology Ocean University of China Qingdao 266003 China Department of Aquatic science Burapha University Chonburi 20131 Thailand Department of Microbiology and environmental science Program Faculty of Science Burapha University Chonburi 20131 Thailand

Amphioxus, Branchiostoma belcheri, a closest relative of vertebrates, is at a high risk of extinction due to a combination of low effective population size, altered native habitats and environmental pollution, yet little is known about cryopreservation of its gametes. This study deals with the cryopreservation of amphioxus senlen. The main findings are that （1） the extender of Yao et al. is the best one among the four extenders examined; （2） the appropriate ratio of semen to extender of Yao et al. plus cryoprotectant is from 1：5 to 1：7; （3） dimethyl sulfoxide （DMSO） and methanol are the better cryoprotectants than glycerol, with DMSO giving the best results; （4） the eggs fertilized with post-thaw spermatozoa are capable of developing to at least hatching stage, and the highest hatching rate is （12.4±3.0）%. This is the first report on freezing and thawing of amphioxus spermatozoa, providing a simple and practical protocol for cryopreservation of amphioxus spermatozoa and laying a foundation for safeguarding this endangered species.

关键词： amphioxus Branehiostoma beleheri cryopreservation spermatozoa motility

INTERVAL FINITE VOLUME METHOD FOR UNCERTAINTY SIMULATION OF TWO-DIMENSIONAL RIVER WATER QUALITY

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Journal of Hydrodynamics 2004年第4期16卷 455-463页

作者： HELi ZENGGuang-ming] HUANGGuo-he LUHong-wei DepartmentofenvironmentalSystemEngineering UniversityofReginaSaskatchewanS4S0A2Canada DepartmentofenvironmentalscienceandEngineering HunanUniversityChangsha410082China

Under the interval uncertainties, by incorporating the discretization form offinite volume method and interval algebra theory, an Interval Finite Volume Method (IF-VM) wasdeveloped to solve water quality simulation issues for two-dimensional river when lacking effectivedata of flow velocity and flow quantity. The IFVM was practically applied to a segment of theXiangjiang River because the Project of Hunan Inland Waterway Multipurpose must be started workingafter the environmental impact assessment for it. The simulation results suggest that there existrather apparent pollution zones of BOD_5 downstream the Dongqiaogang discharger and that of CODdownstream Xiaoxiangjie discharger, but the pollution sources have no impact on the safety of thethree water plants located in this river segment. Although the developed IFVM is to be perfected, itis still a powerful tool under interval uncertainties for water environmental impact assessment,risk analysis, and water quality planning, etc. besides water quality simulation studied in thispaper.

关键词： interval finite volume method (IFVM) uncertainty simulation water quality

NUMERIcaL ANALYSIS OF THE PERFORMANCE OF HORIZONTAL AND WAVY SUBSURFACE FLOW CONSTRUCTED WETLANDS

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Journal of Hydrodynamics 2011年第3期23卷 339-347页

作者： WANG Jun HUANG Sui-liang HE Cheng-da NG Chiu-On College of environmental science and Engineering Nankai University Tianjin 300071 China Numerical Simulation Group for Water Environment Key Laboratory of Pollution Processes and EnvironmentalCriteria of Ministry of Education Tianjin Key Laboratory of Environmental Remediation and Pollution ControlCollege of Environmental Science and Engineering Nankai University Tianjin 300071 China College of environmental science and Engineering Yangzhou University Yangzhou 225009 China Department of Mechanical Engineering The University of Hong Kong Hong Kong China

A three-dimensional numerical model is proposed for modeling the TP transport in the Horizontal Subsurface Flow （HSSF） and Wavy subsurface Flow （WSSF） constructed wetland in this article. Both numerical simulations and physical experiments indicate that the removal efficiency of WSSF is higher than that of HSSF. The difference ofperforrnance in removing pollutants, e.g., Total Phosphorus （TP）, between HSSF and WSSF is numerically analyzed from three interactive aspects, that is, the hydraulic behavior, the substrate and the plant roots. It is shown that the dead zone volume in WSSF is smaller than in HSSF with less short circuiting. The soil in the top layer is more used in WSSF than in HSSF. The TP uptake by the plant roots in WSSF is higher than that in HSSF.

关键词： numerical model constructed wetland hydraulic behavior Retention Time Distribution (RTD) removal efficiency

Damage and progressive failure of concrete structures using non-local peridynamic modeling

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science China(Technological sciences) 2011年第3期54卷 591-596页

作者： HUANG Dan1,2, ZHANG Qing1,2 & QIAO PiZhong1,3 1 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai university, Nanjing 210098, China 2 Department of Engineering Mechanics, Hohai university, Nanjing 210098, China 3 Department of Civil and environmental Engineering, Washington State university, Pullman, WA 99164-2910, usa 1. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing 210098 China2. Department of Engineering Mechanics Hohai University Nanjing 210098 China3. Department of Civil and Environmental Engineering Washington State University Pullman WA 99164-2910 USA

Peridynamics (PD), a recently developed theory of solid mechanics, which employs a non-local model of force interaction and makes use of integral formulation rather than the spatial partial differential equations used in the classical continuum mechanics theory, has shown effectiveness and promise in solving discontinuous problems at both macro and micro scales. In this paper, the peridynamics theory is used to analyze damage and progressive failure of concrete structures. A non-local peridynamic model for a rectangular concrete plate is developed, and a central pairwise force function is introduced to describe the interior interactions between particles within some definite distance. Damage initiation, evolution and crack propagation in the concrete model subject to in-plane uni-axial tension, in-plane uni-axial compression and out-of-plane impact load are investigated respectively. The numerical results show that discontinuities appear and grow spontaneously as part of the solution to the peridynamic equations of motion, and no special failure criteria or re-meshing techniques are required, which proves the potential of peridynamic modeling as a promising technique for analyzing the progressive failure of concrete materials and structures.

关键词： concrete damage progressive failure peridynamic model discontinuities

Concentration and distribution of 17 organochlorine pesticides (OCPs) in seawater from the Japan Sea northward to the Arctic Ocean

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science China Chemistry 2010年第5期53卷 1033-1047页

作者： caI MingGang 1,2,QIU canRong 1,SHEN Yuan 1,caI MingHong 3,HUANG ShuiYing 1,QIAN BiHua 1,SUN JiongHui 1 & LIU XiaoYan 1 1Department of Oceanography,College of Oceanography and environmental science,Xiamen university,Xiamen 361005,China 2State Key Laboratory of Marine environmental science,Xiamen university,Xiamen 361005,China 3State Oceanic Administration Key Laboratory for Polar science,Polar Research Institute of China,Shanghai 200136,China 1. Department of Oceanography College of Oceanography and Environmental Science Xiamen University Xiamen 361005 China2. State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China3. State Oceanic Administration Key Laboratory for Polar Science Polar Research Institute of China Shanghai 200136 China

Seventeen classic organochlorine pesticides in surface seawater were studied in terms of their composition pattern as well as their distribution pattern in the areas covering the Japan Sea,Okhotsk Sea,Bering Sea,Chukchi Sea and Arctic *** concentrations varied,but roughly two levels were seen with one ranging between 0.1 and 1 ng L-1 for most HCH isomers and the other lower than 0.1 ng L-1 for other *** the 17 target compounds,HCHs were dominant with a total concentration percentage generally more than 50%,and a relatively high concentration percentage of heptachlor and aldrine was also observed at scattered *** historical long-term trend of several target chemicals in the five sea zones considered was discussed in comparison with previous ***-sea zone comparison was carried out for individual chemicals by comparing the concentration variation in all five sea zones.A higher variation in concentration was generally found in the northern sea zones,namely the Bering Sea,Chukchi Sea and Arctic Ocean,for most target *** sum concentration of the 17 target chemicals displayed a general trend of increasing northward from the Japan Sea to the Okhotsk Sea to the Bering Sea to the Arctic *** latitudinal trends were found forγ-HCH andγ-HCH,and the reason of this difference was discussed by considering their divergence of thermodynamic properties,which could contribute to a slightly different fractionation effect during their northward transport driven by atmospheric long range *** source of the HCHs was identified by analyzing theγ-HCH/γ-HCH ratio,which was less than 4 without exception,indicating a component characteristic featuring a mixture of technical HCHs and *** addition,the vertical distribution ofγ-HCH,γ-HCH and their ratio at station B80 was *** patterns were found in the upper 300 m while in layers from 300 m downward to 3500 m the patterns were fairly *** vertical p

关键词： organochlorine pesticides Arctic Ocean solid-phase extraction solid-phase microextraction

A study on the spatial flow intensity of overseas travelers in tourist hotspots of China──taking Beijing as an example

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Journal of Geographical sciences 2000年第1期10卷 79-83页

作者： ZHANG Hong, GUO Ying-zhi (College of Tourism and environmental science, Shaanxi Normal university, Xi’an 710062 China, College of management science, Fudan university, Shanghai 200433, China)

Through practical sampling survey for the overseas travelers in the 12 tourist hotspot cities of China, the analytical results of database of the spatial changes for overseas travelers have been established with the help of the software Visual FoxPro. The New concepts such as transferring state, which can be used to study the spatial flow intensity of travelers. is first put forward By analyzing the statistical results, the spatial flow intensity of 12 tourist hotspot cities in China for overseas travelers has been probed At last, a practical research of spatial flow intensity for overseas tourists is carried out in Beijing──the of tourist hotspots of China

关键词： overseas tourists, spatial flow intensity receiving index. transferring state. Beijing

Selective catalytic Reduction of NO with Methane

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Journal of Natural Gas Chemistry 2003年第4期12卷 264-270页

作者： Xiang Gao, Qi Yu, Limin ChenDepartment of environmental science and Engineering, Fudan university, Shanghai 200433, China Department of environmental science and Engineering Fudan University Shanghai 200433 China

The removal of nitrogen oxides from exhaust gases has attracted greatattention in recent years, and many approaches have been developed depending on the ***, the main component of natural gas, has great potential as a NO reductant. In this paper, anumber of catalysts previous reported for this catalytic reduction of NO have been reviewed,including a direct comparison of the relative activities and effective factors of the *** mechanisms have also been explored preliminarily.

关键词： selective catalytic methane mononitrogen monoxide reduction