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Solubility and diffusivity of CO

Guilan Chen, Xingfu Song, Shuying Sun, Yanxia Xu, Jianguo Yu

《化学科学与工程前沿(英文)》 2016年 第10卷 第4期   页码 480-489 doi: 10.1007/s11705-016-1603-1

摘要: The absorption of CO in insoluble organic amine is crucial for understanding the mechanism of coupled reaction-extraction-crystallization process between aqueous chloride and CO . In this study, the solubility and diffusivity of CO in -butanol+ N235 system were measured and reported. The absorption of CO in the system is a physical absorption behavior and the solubility of CO decreases with the increase of the mass fraction of N235. The diffusivity of CO increases firstly and then decreases with the increase in the mass fraction of N235. Moreover, the absorption mechanism of CO in the coupled reaction-extraction-crystallization process was investigated and identified by experiments. The results indicated that in the coupled reaction-extraction-crystallization process, CO is absorbed by the aqueous phase rather than by the organic phase and further transferred into the aqueous phase.

关键词: carbon dioxide     N235     solubility     diffusivity     coupled process    

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in

Yang Zhou, Phillip Choi

《化学科学与工程前沿(英文)》 2017年 第11卷 第3期   页码 440-447 doi: 10.1007/s11705-017-1626-2

摘要: Isothermal-isobaric molecular dynamics simulation was used to study the diffusion mechanism of water in polyurethane- -poly( -isopropyl acrylamide) (PU- -PNIPAm) with a hydrophobic PU/hydrophilic PNIPAm mass ratio of 1.4 to 1 at 298 K and 450 K. Here, the experimental glass transition temperature ( ) of PU is 243 K while that of PNIPAm is 383 K. Different amounts of water up to 15 wt-% were added to PU- -PNIPAm. We were able to reproduce the specific volumes and glass transition temperatures (250 K and 390 K) of PU- -PNIPAm. The computed self-diffusion coefficient of water increased exponentially with increasing water concentration at both temperatures (i.e., following the free volume model of Fujita). It suggested that water diffusion in PU- -PNIPAm depends only on its fractional free volume despite the free volume inhomogeneity. It is noted that at 298 K, PU is rubbery while PNIPAm is glassy. Regardless of temperature, radial distribution functions showed that water formed clusters with sizes in the range of 0.2–0.4 nm in PU- -PNIPAm. At low water concentrations, more clusters were found in the PU domain but at high water concentrations, more in the PNIPAm domain. It is believed that water molecules diffuse as clusters rather than as individual molecules.

关键词: molecular dynamics simulation     amphiphilic block copolymer     free volume     water diffusivity     fujita model    

Effective diffusivity of oxygen in the ash layer of Huadian oil shale semicoke

Yiqun HUANG, Yiran LI, Man ZHANG, Boyu DENG, Hao KONG, Junfeng WANG, Junfu LYU, Hairui YANG, Lingmei WANG

《能源前沿(英文)》 2021年 第15卷 第2期   页码 320-327 doi: 10.1007/s11708-020-0674-3

摘要: Diffusion of oxygen in the ash layer usually dominated the combustion of oil shale semicoke particles due to the high ash content. Thus, effective diffusivity of oxygen in the ash layer was a crucial parameter worthy of careful investigation. In this paper, the effective diffusivity of oxygen in the ash layer of Huadian oil shale semicoke was measured directly using an improved Wicke-Kallenbach diffusion apparatus. The experimental results showed that higher temperature would lead to a higher effective diffusivity and a thicker ash layer had the negative effect. Especially, the effective diffusivity along the direction perpendicular to bedding planes was much lower than that along the direction parallel to bedding planes. In addition, an effective diffusivity model was developed, which could be used to describe the mass transfer of oxygen in the ash layer of oil shale semicoke.

关键词: oil shale semicoke     diffusivity     pore structure     ash layer    

Molecular dynamics simulation of diffusivity

LIU Juanfang, ZENG Danling, LI Qin, GAO Hong

《能源前沿(英文)》 2008年 第2卷 第3期   页码 359-362 doi: 10.1007/s11708-008-0039-9

摘要: Equilibrium molecular dynamics simulation was performed on water to calculate its diffusivity by adopting different potential models. The results show that the potential models have great influence on the simulated results. In addit

关键词: diffusivity     Equilibrium molecular     influence     potential    

Stable expression and control parameters in the numerical simulation of unsaturated flow

Zhiyuan ZHANG; Xu LI; Yongkang WU; Xiaokang LI

《结构与土木工程前沿(英文)》 2022年 第16卷 第12期   页码 1501-1514 doi: 10.1007/s11709-022-0893-2

摘要: The Richards’ equation describes the flow phenomenon in unsaturated porous media and is essential to hydrology and environmental science. This study evaluated the numerical stability of two different forms of the Richards’ equation. Sensitivity analyses were performed to investigate the control parameters of the equation. The results show that the h-form Richards’ equation has better applicability for calculating variable saturation flows than the θ-form Richards’ equation. For the h-form Richards’ equation, the hydraulic conductivity of the soil in the low-suction range and the specific moisture capacity in the high-suction range primarily influenced the solution. In addition, sensitivity analyses indicated that the saturated hydraulic conductivity, initial condition, and air-entry pressure have a higher sensitivity to the simulation results than the saturated water content, rainfall intensity, and decline rate of hydraulic conductivity. Moreover, their correctness needs to be guaranteed first in numerical simulations. The research findings can provide a helpful reference for improving the reliability of numerical simulations of unsaturated flows.

关键词: Richards’ equation     sensitivity analysis     unsaturated soil     hydraulic diffusivity     seepage simulation    

水·水资源·农业节水

刘更另

《中国工程科学》 2000年 第2卷 第7期   页码 39-42

摘要:

文章从水性质特点谈到中国水资源的问题,认为不能单纯用年平均降雨量的多少来判定中国水资源的状况,水资源开发利用的好坏决定于人类社会的调节和管理。中国水资源总的来说是够用的,最大问题是降水量的时空分布不平衡。

中国农民几千年来创造了许多治水蓄水用水的经验。农业节水非常重要,关键在"分散蓄水,分散使用",以减少径流在汇集和分散过程中的损失和污染,在提高水的利用效率方面有一系列的科研和实际工作要做。

关键词:     水资源     农业节水     分散蓄水    

Managing water for life

Daniel P. LOUCKS, Haifeng JIA

《环境科学与工程前沿(英文)》 2012年 第6卷 第2期   页码 255-264 doi: 10.1007/s11783-011-0359-6

摘要: Water is essential for life. In spite of the entire engineering infrastructure devoted to the treatment, regulation and beneficial uses of water, occasionally sufficient quantities and qualities of water become scarce. When this happens, just how do we decide how much less water to allocate to all of us and the activities we engage in to sustain and enhance our quality of life? This paper addresses some of the complexities of answering such a question, especially as society increasingly recognizes the need to provide flow regimes that will maintain healthy aquatic and floodplain ecosystems that also impact the economic, physical and even the spiritual quality of our lives. For we depend on these ecosystems to sustain our wellbeing. We are indeed a part of our ecosystems. We depend upon on aquatic ecosystems to moderate river flow qualities and quantities, reduce the extremes of floods and droughts, reduce erosion, detoxify and decompose waterborne wastes, generate and preserve flood plain soils and renew their fertility, regulate disease carrying organisms, and to enhance recreational benefits of river systems. This question of deciding just how much water to allocate to each water user and for the maintenance of viable aquatic ecosystems, especially when there is not enough, is a complex, and largely political, issue. This issue is likely to become even more complex and political and contentious in the future as populations grow and as water quantities and their qualities become even more variable and uncertain.

关键词: water stress     aquatic ecosystems     sustainable water resource allocations     ecosystem water requirements    

The effect of different agricultural management practices on irrigation efficiency, water use efficiencyand green and blue water footprint

La ZHUO, Arjen Y. HOEKSTRA

《农业科学与工程前沿(英文)》 2017年 第4卷 第2期   页码 185-194 doi: 10.15302/J-FASE-2017149

摘要: This paper explores the effect of varying agricultural management practices on different water efficiency indicators: irrigation efficiency (IE), crop water use efficiency (WUE), and green and blue water footprint (WF). We take winter wheat in an experimental field in Northern China as a case study and consider a dry, average and wet year. We conducted 24 modeling experiments with the AquaCrop model, for all possible combinations of four irrigation techniques, two irrigation strategies and three mulching methods. Results show that deficit irrigation most effectively improved blue water use, by increasing IE (by 5%) and reducing blue WF (by 38%), however with an average 9% yield reduction. Organic or synthetic mulching practices improved WUE (by 4% and 10%, respectively) and reduced blue WF (by 8% and 17%, respectively), with the same yield level. Drip and subsurface drip irrigation improved IE and WUE, but drip irrigation had a relatively large blue WF. Improvements in one water efficiency indicator may cause a decline in another. In particular, WUE can be improved by more irrigation at the cost of the blue WF. Furthermore, increasing IE, for instance by installing drip irrigation, does not necessarily reduce the blue WF.

关键词: field management     irrigation efficiency     water footprint     water productivity     water use efficiency    

Emergency drinking water treatment in source water pollution incident-technology and practice in China

Xiaojian ZHANG , Chao CHEN ,

《环境科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 364-368 doi: 10.1007/s11783-009-0027-2

摘要: An investigation into emergency potable water treatment technologies was conducted to investigate China’s water pollution situation. In order to confirm optimum parameters, the technological efficiency of each pollutant was obtained. About 100 contaminants were tested to find the emergency treatment technologies, most of which were found to be positive. This paper presents the three largest and most significant water pollution incidents in China to date, analyzing cases such as the nitrobenzene pollution incident in the Songhua River in November 2005, the cadmium pollution incident in the Beijiang River in December 2005, and the water crisis with odorous tap water in Wuxi City in May 2007.

关键词: emergency drinking water treatment     water pollution     adsorption     oxidation     precipitation    

Molecular analysis of bacterial community in the tap water with different water ages of a drinking water

Feng Wang, Weiying Li, Yue Li, Junpeng Zhang, Jiping Chen, Wei Zhang, Xuan Wu

《环境科学与工程前沿(英文)》 2018年 第12卷 第3期 doi: 10.1007/s11783-018-1020-4

摘要: Bacterial community in the drinking water distribution system (DWDS) was regulated by multiple environmental factors, many of which varied as a function of water age. In this study, four water samples with different water ages, including finished water (FW, 0 d) and tap water (TW) [TW1 (1 d), TW2(2 d) and TW3(3 d)], were collected along with the mains of a practical DWDS, and the bacterial community was investigated by high-throughput sequencing technique. Results indicated that the residual chlorine declined with the increase of water age, accompanied by the increase of dissolved organic matter, total bacteria counts and bacterial diversity (Shannon). For bacterial community composition, although Proteobacteria phylum (84.12%-97.6%) and Alphaproteobacteria class (67.42%-93.09%) kept dominate, an evident regular was observed at the order level. In detail, the relative abundance of most of other residual orders increased with different degrees from the start to the end of the DWDS, while a downward trend was uniquely observed in terms of Rhizobiales, who was inferred to be chlorine-resistant and be helpful for inhibiting pipes corrosion. Moreover, some OTUs were found to be closely related with species possessing pathogenicity and chlorine-resistant ability, so it was recommended that the use of agents other than chlorine or agents that can act synergically with chlorine should be developed for drinking water disinfection. This paper revealed bacterial community variations along the mains of the DWDS and the result was helpful for understanding bacterial ecology in the DWDS.

关键词: Bacterial community     Water age     High-throughput sequencing technique     Drinking water distribution system    

Comparative genotoxicity of water processed by three drinking water treatment plants with different water

Ting Zhang, Heze Liu, Yiyuan Zhang, Wenjun Sun, Xiuwei Ao

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1214-4

摘要: Genotoxicity of substances is unknown in the water after treatment processes. Genotoxicity decreased by activated carbon treatment but increased by chlorination. Halogenated hydrocarbons and aromatic compounds contribute to genotoxicity. Genotoxicity was assessed by umu test; acute and chronic toxicity by ECOSAR. Inconsistent results confirmed that genotoxicity cannot be assessed by ECOSAR. Advanced water treatment is commonly used to remove micropollutants such as pesticides, endocrine disrupting chemicals, and disinfection byproducts in modern drinking water treatment plants. However, little attention has been paid to the changes in the genotoxicity of substances remaining in the water following the different water treatment processes. In this study, samples were collected from three drinking water treatment plants with different treatment processes. The treated water from each process was analyzed and compared for genotoxicity and the formation of organic compounds. The genotoxicity was evaluated by an umu test, and the acute and chronic toxicity was analyzed through Ecological Structure- Activity Relationship (ECOSAR). The results of the umu test indicated that biological activated carbon reduced the genotoxicity by 38%, 77%, and 46% in the three drinking water treatment plants, respectively, while chlorination increased the genotoxicity. Gas chromatograph-mass spectrometry analysis revealed that halogenated hydrocarbons and aromatic compounds were major contributors to genotoxicity. The results of ECOSAR were not consistent with those of the umu test. Therefore, we conclude that genotoxicity cannot be determined using ECOSAR .

关键词: Drinking water     Treatment process     Genotoxicity     Umu test     Ecological Structure-Activity Relationship    

Bioinspired and biomimetic membranes for water purification and chemical separation: A review

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1412-8

摘要:

•The history of biological and artificial water channels is reviewed.

关键词: Aquaporins     Artificial water channels     Biomimetic membranes     Chemical separation and water purification    

A red water occurrence in drinking water distribution systems caused by changes in water source in Beijing

ZHANG Xiaojian,MI Zilong,WANG Yang,LIU Shuming,NIU Zhangbin,LU Pinpin,WANG Jun,GU Junnong,CHEN Chao

《环境科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 417-426 doi: 10.1007/s11783-013-0558-4

摘要: A red water phenomenon occurred in several communities few days after the change of water source in Beijing, China in 2008. In this study, the origin of this problem, the mechanism of iron release and various control measures were investigated. The results indicated that a significant increase in sulphate concentration as a result of the new water source was the cause of the red water phenomenon. The mechanism of iron release was found that the high-concentration sulphate in the new water source disrupted the stable shell of scale on the inner pipe and led to the release of iron compounds. Experiments showed that the iron release rate in the new source water within pipe section was over 11-fold higher than that occurring within the local source water. The recovery of tap water quality lasted several months despite ameliorative measures being implemented, including adding phosphate, reducing the overall proportion of the new water source, elevating the pH and alkalinity, and utilizing free chlorine as a disinfectant instead of chloramine. Adding phosphate was more effective and more practical than the other measures. The iron release rate was decreased after the addition of 1.5 mg·L orthophosphate- P, tripolyphosphate-P and hexametaphosphate-P by 68%, 83% and 87%, respectively. Elevating the pH and alkalinity also reduced the iron release rate by 50%. However, the iron release rate did not decreased after replacing chloramine by 0.5–0.8 mg·L of free chlorine as disinfectant.

关键词: iron release     drinking water distribution system     sulphate     phosphate     red water control     water quality stability    

标题 作者 时间 类型 操作

Solubility and diffusivity of CO

Guilan Chen, Xingfu Song, Shuying Sun, Yanxia Xu, Jianguo Yu

期刊论文

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in

Yang Zhou, Phillip Choi

期刊论文

Effective diffusivity of oxygen in the ash layer of Huadian oil shale semicoke

Yiqun HUANG, Yiran LI, Man ZHANG, Boyu DENG, Hao KONG, Junfeng WANG, Junfu LYU, Hairui YANG, Lingmei WANG

期刊论文

Molecular dynamics simulation of diffusivity

LIU Juanfang, ZENG Danling, LI Qin, GAO Hong

期刊论文

Stable expression and control parameters in the numerical simulation of unsaturated flow

Zhiyuan ZHANG; Xu LI; Yongkang WU; Xiaokang LI

期刊论文

巨晓洁:用于水处理和水检测的新型功能材料(2022年4月16日)

2022年06月09日

会议视频

水·水资源·农业节水

刘更另

期刊论文

王光谦:全球水循环与水资源利用(2019年10月17日)

王光谦(院士)

2021年01月20日

会议视频

Managing water for life

Daniel P. LOUCKS, Haifeng JIA

期刊论文

The effect of different agricultural management practices on irrigation efficiency, water use efficiencyand green and blue water footprint

La ZHUO, Arjen Y. HOEKSTRA

期刊论文

Emergency drinking water treatment in source water pollution incident-technology and practice in China

Xiaojian ZHANG , Chao CHEN ,

期刊论文

Molecular analysis of bacterial community in the tap water with different water ages of a drinking water

Feng Wang, Weiying Li, Yue Li, Junpeng Zhang, Jiping Chen, Wei Zhang, Xuan Wu

期刊论文

Comparative genotoxicity of water processed by three drinking water treatment plants with different water

Ting Zhang, Heze Liu, Yiyuan Zhang, Wenjun Sun, Xiuwei Ao

期刊论文

Bioinspired and biomimetic membranes for water purification and chemical separation: A review

期刊论文

A red water occurrence in drinking water distribution systems caused by changes in water source in Beijing

ZHANG Xiaojian,MI Zilong,WANG Yang,LIU Shuming,NIU Zhangbin,LU Pinpin,WANG Jun,GU Junnong,CHEN Chao

期刊论文