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Migration of ammonium nitrogen in ion-absorbed rare earth soils during and post mining: a column study

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1702-4

摘要:

● Column experiments with an inclined slope were applied to simulate NH4–N transport.

关键词: Ion-absorbed rare earth     Ammonium nitrogen transport     HYDRUS-2D     Numerical simulation    

CRITICAL PROCESSES AND MAJOR FACTORS THAT DRIVE NITROGEN TRANSPORT FROM FARMLAND TO SURFACE WATER BODIES

《农业科学与工程前沿(英文)》 2023年 第10卷 第4期   页码 541-552 doi: 10.15302/J-FASE-2023518

摘要:

Agricultural non-point source pollution is increasingly an important issue affecting surface water quality. Currently, the majority of the studies on nitrogen loss have focused on the agricultural field scale, however, the response of surface water quality at the watershed scale into the nitrogen loss at the field scale is poorly understood. The present study systematically reviewed the critical processes and major factors that nitrogen transport from farm fields to surface water bodies. The critical processes of farmland nitrogen entering surface water bodies involve the processes of nitrogen transport from farmland to ditches and the transformation processes of nitrogen during migration in ditches/rivers. Nitrogen transport from farmland to ditches is one of the prerequisites and critical processes for farmland nitrogen transport to surface water bodies. The transformation of nitrogen forms in ditches/rivers is an intermediate process in the migration of nitrogen from farmland to surface water bodies. Nitrogen loss from farmland is related to soil storage and exogenous inputs. Therefore, nitrogen input management should not only consider the current input, but also the contribution of soil storage due to the historical surpluses. Ditches/rivers have a strong retention capacity for nitrogen, which will significantly affect the process of farmland nitrogen entering surface water bodies. The factors affecting nitrogen transformation in river/ditches can be placed in four categories: (1) factors affecting hydraulic retention time, (2) factors affecting contact area, (3) factors affecting biological activity, and (4) forms and amount of nitrogen loading to river/ditches. Ditch systems are more biologically (including plants and microbes) active than rivers with biological factors having a greater influence on nitrogen transformation. When developing pollution prevention and control strategies, ecological ditches can be constructed to increase biological activity and reduce the amount of surplus nitrogen entering the water body. The present research should be valuable for the evaluation of environment impacts of nitrogen loss and the non-point source pollution control.

关键词: nitrogen     loss from soil     transformation     farm field scale     watershed scale    

Micro-analysis of nitrogen transport and conversion inside activated sludge flocs using microelectrodes

Lei WANG, Yongtao LV, Xudong WANG, Yongzhe YANG, Xiaorong BAI

《环境科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 633-638 doi: 10.1007/s11783-011-0329-z

摘要: To investigate the nitrogen transport and conversion inside activated sludge flocs, micro-profiles of O , NH , NO , NO , and pH were measured under different operating conditions. The flocs were obtained from a laboratory-scale sequencing batch reactor. Nitrification, as observed from interfacial ammonium and nitrate fluxes, was higher at pH 8.5, than at pH 6.5 and 7.5. At pH 8.5, heterotrophic bacteria used less oxygen than nitrifying bacteria, whereas at lower pH heterotrophic activity dominated. When the ratio of C to N was decreased from 20 to 10, the ammonium uptake increased. When dissolved oxygen (DO) concentration in the bulk liquid was decreased from 4 to 2 mg·L , nitrification decreased, and only 25% of the DO influx into the flocs was used for nitrification. This study indicated that nitrifying bacteria became more competitive at a higher DO concentration, a higher pH value (approximately 8.5) and a lower C/N.

关键词: nitrogen transport     activated sludge flocs     heterotrophic bacteria     nitrifying bacteria     microelectrodes    

Mechanism studies on nitrogen removal when treating ammonium-rich leachate by sequencing batch biofilm

XU Zhengyong, YANG Zhaohui, ZENG Guangming, XIAO Yong, DENG Jiuhua

《环境科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 43-48 doi: 10.1007/s11783-007-0008-2

摘要: The nitrogen removal mechanism was studied and analyzed when treating the ammonium-rich landfill leachate by a set of sequencing batch biofilm reactors (SBBRs), which was designed independently. At the liquid temperature of (32?0.4)?C, and after a 58-days domestication period and a 33-days stabilization period, the efficiency of ammonium removal in the SBBR went up to 95%. Highly frequent intermittent aeration suppressed the activity of nitratebacteria, and also eliminated the influence on the activity of anaerobic ammonium oxidation (ANAMMOX) bacteria and nitritebacteria. This influence was caused by the accumulation of nitrous acid and the undulation of pH. During the aeration stage, the concentration of dissolved oxygen was controlled at 1.2 1.4 mg/L. The nitritebacteria became dominant and nitrite accumulated gradually. During the anoxic stage, along with the concentration debasement of the dissolved oxygen, ANAMMOX bacteria became dominant; then, the nitrite that was accumulated in the aeration stage was wiped off with ammonium simultaneously.

关键词: undulation     33-days stabilization     concentration debasement     temperature     accumulation    

Microprofiles of activated sludge aggregates using microelectrodes in completely autotrophic nitrogen

Yongtao LV,Xuan CHEN,Lei WANG,Kai JU,Xiaoqiang CHEN,Rui MIAO,Xudong WANG

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 390-398 doi: 10.1007/s11783-015-0818-6

摘要: Microsensor measurements and fluorescence in situ hybridization (FISH) analysis were combined to investigate the microbial populations and activities in a laboratory-scale sequencing batch reactor (SBR) for completely autotrophic nitrogen removal over nitrite (CANON). Fed with synthetic wastewater rich in ammonia, the SBR removed 82.5±5.4% of influent nitrogen and a maximum nitrogen-removal rate of 0.52 kgN·m ·d was achieved. The FISH analysis revealed that aerobic ammonium-oxidizing bacteria (AerAOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) dominated the community. To quantify the microbial activities inside the sludge aggregates, microprofiles were measured using pH, dissolved oxygen (DO), , and microelectrodes. In the outer layer of sludge aggregates (0–700 μm), nitrite-oxidizing bacteria (NOB) showed high activity with 4.1 μmol·cm ·h of maximum nitrate production rate under the condition of DO concentration higher than 3.3 mg·L . Maximum AerAOB activity was detected in the middle layer (depths around 1700 μm) where DO concentration was 1.1 mg·L . In the inner layer (2200–3500 μm), where DO concentration was below 0.9 mg·L , AnAOB activity was detected. We thus showed that information obtained from microscopic views can be helpful in optimizing the SBR performance.

关键词: microelectrodes     CANON     aerobic ammonium-oxidizing bacteria     anaerobic ammonium-oxidizing bacteria     nitrite-oxidizing bacteria    

Nitrifying population dynamics in a redox stratified membrane biofilm reactor (RSMBR) for treating ammonium-rich

Rongchang WANG, Xinmin ZHAN, Yalei ZHANG, Jianfu ZHAO

《环境科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 48-56 doi: 10.1007/s11783-011-0305-7

摘要: Nitrogen removal performance and nitrifying population dynamics were investigated in a redox stratified membrane biofilm reactor (RSMBR) under oxygen limited condition to treat ammonium-rich wastewater. When the loading rate increased from 11.1±1.0 to , the nitrogen removal in the RSMBR system increased from 18.0±9.6 mgN·d to 128.9±61.7 mgN·d . Shortcut nitrogen removal was achieved with nitrite accumulation of about . Confocal micrographs showed the stratified distributions of nitrifiers and denitrifiers in the membrane aerated biofilms (MABs) at day 120, i.e., ammonia and nitrite oxidizing bacteria (AOB and NOB) were dominant in the region adjacent to the membrane, while heterotrophic bacteria propagated at the top of the biofilm. Real-time qPCR results showed that the abundance of gene was two orders of magnitude higher than the abundance of gene in the MABs. However, the gene was always detected during the operation time, which indicates the difficulty of complete washout of NOB in MABs. The growth of heterotrophic bacteria compromised the dominance of nitrifiers in biofilm communities, but it enhanced the denitrification performance of the RSMBR system. Applying a high ammonia loading together with oxygen limitation was found to be an effective way to start nitrite accumulation in MABs, but other approaches were needed to sustain or improve the extent of nitritation in nitrogen conversion in MABs.

关键词: ammonium-rich wastewater     membrane biofilm reactor     nitrification     redox stratification     shortcut nitrogen removal    

the direct conversion of NHHCO electrolyte to syngas on Ag/Zn zeolitic imidazolate framework derived nitrogen-carbon

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1196-1207 doi: 10.1007/s11705-022-2289-1

摘要: The electrochemical reduction of NH4HCO3 to syngas can bypass the high energy consumption of high-purity CO2 release and compression after the ammonia-based CO2 capture process. This technology has broad prospects in industrial applications and carbon neutrality. A zeolitic imidazolate framework-8 precursor was introduced with different Ag contents via colloid chemical synthesis. This material was carbonized at 1000 °C to obtain AgZn zeolitic imidazolate framework derived nitrogen carbon catalysts, which were used for the first time for boosting the direct conversion of NH4HCO3 electrolyte to syngas. The AgZn zeolitic imidazolate framework derived nitrogen carbon catalyst with a Ag/Zn ratio of 0.5:1 achieved the highest CO Faradaic efficiency of 52.0% with a current density of 1.15 mA·cm–2 at –0.5 V, a H2/CO ratio of 1–2 (–0.5 to –0.7 V), and a stable catalytic activity of more than 6 h. Its activity is comparable to that of the CO2-saturated NH4HCO3 electrolyte. The highly discrete Ag-Nx and Zn-Nx nodes may have combined catalytic effects in the catalysts synthesized by appropriate Ag doping and sufficient carbonization. These nodes could increase active sites of catalysts, which is conducive to the transport and adsorption of reactant CO2 and the stability of *COOH intermediate, thus can improve the selectivity and catalytic activity of CO.

关键词: Ag catalyst     zeolitic imidazolate framework     CO2 electroreduction     ammonium bicarbonate electrolyte     syngas    

Overlooked nitrogen-cycling microorganisms in biological wastewater treatment

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1426-2

摘要:

• AOA and comammox bacteria can be more abundant and active than AOB/NOB at WWTPs.

关键词: Ammonia oxidizing archaea (AOA)     Complete ammonia oxidizing (comammox) bacteria     Dissimilatory nitrate reduction to ammonium (DNRA) bacteria     Nitrate/nitrite-dependent anaerobic methane oxidizing (NOx-DAMO) microorganisms     Engineering application    

Optimization of process parameters for mature landfill leachate pretreatment using MAP precipitation

Wei LI, Xiaowen DING, Min LIU, Yuewen GUO, Lei LIU

《环境科学与工程前沿(英文)》 2012年 第6卷 第6期   页码 892-900 doi: 10.1007/s11783-012-0440-9

摘要: Chemical precipitation is a useful technology as a pretreatment to treat mature landfill leachate with high concentrations of ammonium-nitrogen ( ) and refractory organic compounds. Orthogonal experiments and factorial experiments were carried out to determine the optimal conditions enhancing the magnesium ammonium phosphate (MAP) precipitation process, and the experimental results demonstrated that the removal rate of was more than 85% when MgO and NaH PO ·2H O were applied as external sources of magnesium and phosphorous under the optimal conditions that molar ratio n(Mg)∶n(N)∶n(P) = 1.4∶1∶0.8, reaction time 60 min, original pH of leachate and settling time 30 min. In the precipitation process, pH could be maintained at the optimal range of 8–9.5 because MgO could release hydroxide ions to consume hydrogen ions. Calcium ions and carbonate ions existed in the leachate could affect the precipitation process, which resulted in the decrease of removal efficiency. The residues of MAP sediments decomposed by heating under alkaline conditions can be reused as the sources of phosphorous and magnesium for the removal of high concentrations of , and up to 90% of ammonium could be released under molar ratio of n[OH]∶n[MAP] = 2.5∶1, heating temperature 90°C and heating time 2h.

关键词: magnesium ammonium phosphate precipitation     mature landfill leachate     optimization     ammonium-nitrogen    

通过厌氧氨氧化实现活性氮生物地球化学循环 Review

Guibing Zhu,Bangrui Lan,Shuci Liu,Cameron M. Callbeck,Shanyun Wang,Liping Jiang,Asheesh Kumar Yadav,Jan Vymazal,Mike S. M. Jetten,Ganlin Zhang,Yongguan Zhu,

《工程(英文)》 2024年 第38卷 第7期   页码 176-184 doi: 10.1016/j.eng.2023.09.013

摘要:

The availability of nitrogen (N) is crucial for both the productivity of terrestrial and aquatic ecosystems globally. However, the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the global nitrogen cycle (N-cycle) past its safe operating limits, leading to severe nitrogen pollution and the production of significant amounts of greenhouse gas nitrous oxide (N2O). The anaerobic ammonium oxidation (anammox) mechanism can counteract the release of ammonium and N2O in many oxygen-limited situations, assisting in the restoration of the homeostasis of the Earth's N biogeochemistry. In this work, we looked into the characteristics of the anammox hotspots' distribution across various types of ecosystems worldwide. Anammox hotspots are present at diverse oxic–anoxic interfaces in terrestrial systems, and they are most prevalent at the oxic–anoxic transition zone in aquatic ecosystems. Based on the discovery of an anammox hotspot capable of oxidizing ammonium anoxically into N2 without N2O by-product, we then designed an innovative concept and technical routes of nature-based anammox hotspot geoengineering for climate change, biodiversity loss, and efficient utilization of water resources. After 15 years of actual use, anammox hotspot geoengineering has proven to be effective in ensuring clean drinking water, regulating the climate, fostering plant and animal diversity, and enhancing long-term environmental quality. The sustainable biogeoengineering of anammox could be a workable natural remedy to resolve the conflicts between environmental pollution and food security connected to N management.

关键词: biogeochemical N-cycle     oxic–anoxic interface     nature-based solution     biogeoengineering     nitrogen sustainable development    

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated

Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG

《环境科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 291-297 doi: 10.1007/s11783-010-0270-6

摘要: Shortcut nitrification-denitrification, anaerobic ammonium oxidation (ANAMMOX), and methanogenesis have been successfully coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system. As fed different synthetic wastewater with chemical oxygen demand (COD) of 300–1200 mg·L and of 30–120 mg·L at the outer recycle ratio of 200%, the influence of influent on ANAMMOX in the integrated system was investigated in this paper. The experimental results showed that higher COD concentration caused an increase in denitrification and methanogenesis but a decrease in ANAMMOX; however, when an influent with the low concentration of COD was used, the opposite changes could be observed. Higher influent concentration favored ANAMMOX when the COD concentration of influent was fixed. Therefore, low ratio would decrease competition for nitrite between ANAMMOX and denitrification, which was favorable for reducing the negative effect of organic COD on ANAMMOX. The good performance of the integrated system indicated that the bacterial community of denitrification, ANAMMOX, and methanogenesis could be dynamically maintained in the sludge of EGSB reactor for a certain range of influent.

关键词: Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system     the influence of influent     anaerobic ammonium oxidation (ANAMMOX)     shortcut nitrification-denitrification     methano-genesis    

Filtration ability of hollow fiber membrane for production of magnesium ammonium phosphate crystals by

H. Watamura, H. Marukawa, I. Hirasawa

《化学科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 55-59 doi: 10.1007/s11705-013-1312-y

摘要: Relationship between magnesium ammonium phosphate (MAP) crystal properties and the filtration ability of hollow fiber membrane (HFM) were investigated. Phosphorus recovery process by crystallization has a problem that it produces a large amount of fine crystals. So improvement of the crystallization process by combining with filtration was discussed. MAP crystals were obtained by batch reaction crystallization and the filtration characteristics were investigated. The filtration was evaluated by the specific filtration resistance ( ) on HFM. Filtered slurry was prepared with each suspension density and crystal size distribution. The solution was filtered at constant pressure of 0.02 MPa and the filtration time on each filtrated volume was recorded. As a result, decreases exponentially with suspension density increasing from 0.25 g/L to 0.5 g/L and decreases moderately with suspension density increasing from 0.5 g/L to 1.5 g/L. of large crystals decreases exponentially at less suspension density than of small crystals does. Also, increases as the ratio of the fractured crystals increases.

关键词: membrane separation     crystallization     MAP    

New insights into the formation of ammonium nitrate from a physical and chemical level perspective

《环境科学与工程前沿(英文)》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1737-6

摘要:

● Factor analysis of ammonium nitrate formation based on thermodynamic theory.

关键词: Ammonium nitrate formation     Thermodynamic theory     Aerosol liquid water content     Source apportionment    

Enabling nickel ferrocyanide nanoparticles for high-performance ammonium ion storage

《化学科学与工程前沿(英文)》 2023年 第17卷 第2期   页码 226-235 doi: 10.1007/s11705-022-2198-3

摘要: Prussian blue and its analogs are extensively investigated as a cathode for ammonium-ion batteries. However, they often suffer from poor electronic conductivity. Here, we report a Ni2Fe(CN)6/multiwalled carbon nanotube composite electrode material, which is prepared using a simple coprecipitation approach. The obtained material consists of nanoparticles with sizes 30–50 nm and the multiwalled carbon nanotube embedded in it. The existence of multiwalled carbon nanotube ensures that the Ni2Fe(CN)6/multiwalled carbon nanotube composite shows excellent electrochemical performance, achieving a discharge capacity of 55.1 mAh·g–1 at 1 C and 43.2 mAh·g–1 even at 15 C. An increase in the ammonium-ion diffusion coefficient and ionic/electron conductivity based on kinetic investigations accounts for their high performance. Furthermore, detailed ex situ characterizations demonstrate that Ni2Fe(CN)6/multiwalled carbon nanotube composite offers three advantages: negligible lattice expansion during cycling, stable structure, and the reversible redox couple. Therefore, the Ni2Fe(CN)6/multiwalled carbon nanotube composite presents a long cycling life and high rate capacity. Finally, our study reports a desirable material for ammonium-ion batteries and provides a practical approach for improving the electrochemical performance of Prussian blue and its analogs.

关键词: nickel ferrocyanides     NH4+     electrochemistry     Prussian blue     aqueous ammonium ion batteries    

Thermal decomposition mechanism of ammonium sulfate catalyzed by ferric oxide

Xingfu SONG, Jingcai ZHAO, Yunzhao LI, Ze SUN, Jianguo YU

《化学科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 210-217 doi: 10.1007/s11705-013-1320-y

摘要: The decomposition mechanism of ammonium sulfate catalyzed by ferric oxide was investigated in this paper. The decomposition kinetics parameters were determined via a global optimization of the Kissinger iterative method using the non-isothermal thermogravimetric analysis data. The products and intermediates were synchronously characterized by X-ray diffraction and mass spectrometry. The obtained results indicate that the decomposition process of ammonium sulfate catalyzed by ferric oxide can be divided into four stages of which the activation energies are 123.64, 126.58, 178.77 and 216.99 kJ·mol respectively. The decomposition mechanisms at the first and the fourth stage both belong to Mample power theorem, the second stage belongs to Avrami-Erofeev equation and the third belongs to contracting sphere (volume) equation. The corresponding pre-exponential factors ( ) are calculated simultaneously.

关键词: ammonium sulfate     decomposition kinetics     ferric oxide     thermogravimetric analysis    

标题 作者 时间 类型 操作

Migration of ammonium nitrogen in ion-absorbed rare earth soils during and post mining: a column study

期刊论文

CRITICAL PROCESSES AND MAJOR FACTORS THAT DRIVE NITROGEN TRANSPORT FROM FARMLAND TO SURFACE WATER BODIES

期刊论文

Micro-analysis of nitrogen transport and conversion inside activated sludge flocs using microelectrodes

Lei WANG, Yongtao LV, Xudong WANG, Yongzhe YANG, Xiaorong BAI

期刊论文

Mechanism studies on nitrogen removal when treating ammonium-rich leachate by sequencing batch biofilm

XU Zhengyong, YANG Zhaohui, ZENG Guangming, XIAO Yong, DENG Jiuhua

期刊论文

Microprofiles of activated sludge aggregates using microelectrodes in completely autotrophic nitrogen

Yongtao LV,Xuan CHEN,Lei WANG,Kai JU,Xiaoqiang CHEN,Rui MIAO,Xudong WANG

期刊论文

Nitrifying population dynamics in a redox stratified membrane biofilm reactor (RSMBR) for treating ammonium-rich

Rongchang WANG, Xinmin ZHAN, Yalei ZHANG, Jianfu ZHAO

期刊论文

the direct conversion of NHHCO electrolyte to syngas on Ag/Zn zeolitic imidazolate framework derived nitrogen-carbon

期刊论文

Overlooked nitrogen-cycling microorganisms in biological wastewater treatment

期刊论文

Optimization of process parameters for mature landfill leachate pretreatment using MAP precipitation

Wei LI, Xiaowen DING, Min LIU, Yuewen GUO, Lei LIU

期刊论文

通过厌氧氨氧化实现活性氮生物地球化学循环

Guibing Zhu,Bangrui Lan,Shuci Liu,Cameron M. Callbeck,Shanyun Wang,Liping Jiang,Asheesh Kumar Yadav,Jan Vymazal,Mike S. M. Jetten,Ganlin Zhang,Yongguan Zhu,

期刊论文

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated

Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG

期刊论文

Filtration ability of hollow fiber membrane for production of magnesium ammonium phosphate crystals by

H. Watamura, H. Marukawa, I. Hirasawa

期刊论文

New insights into the formation of ammonium nitrate from a physical and chemical level perspective

期刊论文

Enabling nickel ferrocyanide nanoparticles for high-performance ammonium ion storage

期刊论文

Thermal decomposition mechanism of ammonium sulfate catalyzed by ferric oxide

Xingfu SONG, Jingcai ZHAO, Yunzhao LI, Ze SUN, Jianguo YU

期刊论文