In order to improve water quality of middle ancient canal in Zhenjiang city a pollution control project was carried out.The research area is the middle catchment area of the ancient canal river system in the old town ...In order to improve water quality of middle ancient canal in Zhenjiang city a pollution control project was carried out.The research area is the middle catchment area of the ancient canal river system in the old town of Zhenjiang. The specific research object is the runoff of the outfall of rainwater-sewage confluence in the area. On the basis of detecting and analyzing the water yield and water quality of the runoff of rainwater-sewage confluence a combined technology which contains four independent continuous processes for lowering pollution load was developed and system equipment was established and put into operation. The processing effects of the project were monitored and analyzed.The results show that the pollution control project of outfall runoff is efficient which decreases the pollution load including chemical oxygen demand COD total phosphorus TP suspended solids SS and ammonia-nitrogen NH3-N .As a result the water environment of the ancient canal is protected.展开更多
AIM: To characterize the peripheral T-cell subpopulation profiles and their correlation with hepatitis B virus (HBV) replication in different dinical stages of chronic HBV infection. METHODS: A total of 422 patien...AIM: To characterize the peripheral T-cell subpopulation profiles and their correlation with hepatitis B virus (HBV) replication in different dinical stages of chronic HBV infection. METHODS: A total of 422 patients with chronic HBV infection were enrolled in this study. The patients were divided into three stages: immune-tolerant stage, immune active stage, and immune-inactive carrier stage. Composition of peripheral T-cell subpopulations was determined by flow cytometry. HBV markers were detected by enzyme-linked immunosorbent assay. Serum HBV DNA load was assessed by quantitative real-time poiymerase chain reaction.RESULTS: CD8^+ T-cells were significantly higher in patients at the immune-tolerant stage than in patients at the immune-active and -inactive carrier stages (36.87 ± 7.58 vs 34.37 ± 9.07, 36.87 ± 7.58 vs 28.09 ± 5.64, P 〈 0.001). The peripheral blood in patients at the immune-tolerant and immune active stages contained more CD8^+ T-cells than CD4^+ T-cells (36.87 ± 7.58 vs 30.23 ± 6.35, 34.37 ± 9.07 vs 30.92 ± 7.40, P 〈 0.01), whereas the peripheral blood in patients at the immune- inactive carrier stage and in normal controls contained less CD8^+ T-cells than CD4^+ T-cells (28.09 ± 5.64 vs 36.85 ±6.06, 24.02 ± 4.35 vs 38.94 ± 3.39, P 〈 0.01). ANOVA linear trend test showed that CD8^+ T-cells were significantly increased in patients with a high viral load (39.41 ± 7.36, 33.83 ± 7.50, 31.81 ± 5.95 and 26.89 ± 5.71, P 〈 0.001), while CD4^+ T-cells were significantly increased in patients with a low HBV DNA load (37.45 ± 6.24, 33.33 ± 5.61, 31.58 ± 6.99 and 27.56 ± 5.49, P 〈 0.001). Nultiple regression analysis displayed that log copies of HBV DNA still maintained its highly significant coefficients for T-cell subpopulations, and was the strongest predictors for variations in CD3^+, CD4^+ and CD8^+ cells and CD4^+/CD8^+ ratio after adjustment for age at HBV-infection, maternal HBV-infection status, presence of hepatitis B e antigen and HBV mutation.CONCLUSION: Differences in peripheral T-cell subpopulation profiles can be found in different clinical stages of chronic HBV infection. T-cell impairment is significantly associated with HBV load.展开更多
To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake, China, we studied water quality and nutrient budget in Chinese mitten crab (Eriocheir sinensis) farm ponds in the eastern...To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake, China, we studied water quality and nutrient budget in Chinese mitten crab (Eriocheir sinensis) farm ponds in the eastern part of the lake from November 2007 to December 2009. We estimated the nitrogen (N), phosphorus (P), and chemical oxygen demand (COD) loads. Materials input and output ponds, water exchange, and applied management practices of 838.5-hm2 crab ponds were surveyed using questionnaires. Water quality of 12 ponds, which were located no more than 2 km from East Taihu Lake, were monitored. The results show that water quality in the crab ponds was better than reference data. Feeds, including corn seed, commercial feed, trash fish, and gastropod, were the major sources of N and P input in the crab ponds, contributing 88.7% and 94.9%, respectively. In total, 60.5% of N and 37.3% of P were sequestered by macrophytes, and only 15.7% and 8.5% of them were discharged as effluent. The net loads of N and P in effluent were 16.43 kg/hm2/cycle and 2.16 kg/hm2/cycle, respectively, while the COD load was -17.88 kg/hm2/cycle. This indicated that crab farming caused minor negative impact on the trophic status of the lake area, which was attenuated by macrophytes. However, wastewater purification is still necessary in crab faming.展开更多
This study estimated pollutant load from Kahuwa micro-catchment into Lake Kivu. The micro-catchment was sampled monthly for a year at six locations to capture the contribution of agricultural land, industries and comm...This study estimated pollutant load from Kahuwa micro-catchment into Lake Kivu. The micro-catchment was sampled monthly for a year at six locations to capture the contribution of agricultural land, industries and commercial blocks. Both wet and dry depositions in terms of TN (total nitrogen) and TP (total phosphorus) were estimated monthly. The level of pollution was estimated using LISEC index and IPO (organic pollution indices). Results show that Kahuwa River micro-catchment is polluted mainly by waste dumping sites and industries within the micro-catchment. The general load to the outlet was respectively about 0.35 tons per year (t/yr) for BODs, 1.9 t/yr for COD, 32.73 t/yr for TP and 224.37 t/yr for TN. Atmospheric deposition of nutrient contributed for about 4% and 18% of TP, 3% and 0.01% of TN during dry and wet deposition, respectively.展开更多
The key objective of this research was to estimate the Ni and Cr contents of soil around the Baghjar Chromite Mine(BCM)of Sabzevar Ophiolite Belt,Northeastern Iran,and assess the degree of soil pollution using the p...The key objective of this research was to estimate the Ni and Cr contents of soil around the Baghjar Chromite Mine(BCM)of Sabzevar Ophiolite Belt,Northeastern Iran,and assess the degree of soil pollution using the pollution indices.Soil samples(0-20 cm depth) were collected at various distances from the BCM.In the present research,heavy metals(Cr and Ni) in soil samples were analyzed by atomic absorption spectrometry to detect their concentrations and contour maps were produced to explain the metal spatial distribution.Also,the degree of metal pollution was quantified.The results indicate that the soils in the studied area are contaminated by Cr and Ni.The corresponding concentrations for Cr and Ni are(156.19±24.45) and(321.7±133.27) mg/kg,respectively,which exceed the corresponding maximum allowable concentrations in soils.The different indices demonstrate that soils around chromite mine are significantly contaminated with Cr and Ni,suggesting several times higher levels of toxic metals than normal ranges.The above results revealed that the heavy metal concentrations increase with increasing the distance from the mine and mining pollutants can be transported to long distances from their sources.展开更多
Non-point source(NPS) pollution has become a major source of water pollution. A combination of models would provide the necessary direction and approaches designed to control NPS pollution through land use planning. I...Non-point source(NPS) pollution has become a major source of water pollution. A combination of models would provide the necessary direction and approaches designed to control NPS pollution through land use planning. In this study, NPS pollution load was simulated in urban planning, historic trends and ecological protection land use scenarios based on the Conversion of Land Use and its Effect at Small regional extent(CLUE-S) and Soil and Water Assessment Tool(SWAT) models applied to Hunhe-Taizi River Watershed, Liaoning Province, China. Total nitrogen(TN) and total phosphorus(TP) were chosen as NPS pollution indices. The results of models validation showed that CLUE-S and SWAT models were suitable in the study area. NPS pollution mainly came from dry farmland, paddy, rural and urban areas. The spatial distribution of TN and TP exhibited the same trend in 57 sub-catchments. The TN and TP had the highest NPS pollution load in the western and central plains, which concentrated the urban area and farm land. The NPS pollution load would increase in the urban planning and historic trends scenarios, and would be even higher in the urban planning scenario. However, the NPS pollution load decreased in the ecological protection scenario. The differences observed in the three scenarios indicated that land use had a degree of impact on NPS pollution, which showed that scientific and ecologically sound construction could effectively reduce the NPS pollution load in a watershed. This study provides a scientific method for conducting NPS pollution research at the watershed scale, a scientific basis for non-point source pollution control, and a reference for related policy making.展开更多
Developing photosensitizers suitable for the cobalt electrolyte and understanding the structure-property relationship of organic dyes is warranted for the dye-sensitized solar cells (DSSCs). The DSSCs incorporating ...Developing photosensitizers suitable for the cobalt electrolyte and understanding the structure-property relationship of organic dyes is warranted for the dye-sensitized solar cells (DSSCs). The DSSCs incorporating tris(1,10-phenanthroline)eobalt(Ⅱ/Ⅲ)-based redox elec- trolyte and four synthesized organic dyes as photosensitizers are described. The photovoltaic performance of these dyes-sensitized solar cells employing the cobalt redox shuttle and the influences of the w-conjugated spacers of organic dyes upon the photovoltage and photocur- rent of mesoscopic titania solar cells are investigated. It is found that organic dyes with thiophene derivates as linkers are suitable for DSSCs employing cobalt electrolytes. DSSCs sensitized with the as-synthesized dyes in combination with the cobalt redox shuttle yield an overall power conversion efficiency of 6.1% under 100 mW/cm2 AM1.5 G illumination.展开更多
With the current tightening of environmental regulations of waste water treatment, there is a need for the enhancement of the treatment efficiency. This can be done through process changes, or by adding a finishing tr...With the current tightening of environmental regulations of waste water treatment, there is a need for the enhancement of the treatment efficiency. This can be done through process changes, or by adding a finishing treatment after the process, like flotation or filtration. Wetlands are also one possibility for the finishing treatment of waste water. In Finland Wetlands have been used as a polishing treatment for municipal wastewater for approx. 20 years. Most of these are natural wetlands. Using wetlands after efficient wastewater treatment is an economical way of producing high quality treated water and cutting down the pollution load of water bodies. Wetlands have also been used in the control of diffuse pollution in agriculture and forestry.展开更多
Based on the exploring of SWAT model suitability in Hei River Basin, this paper analyze quantitatively and compare non-point source pollution loads occurred under different land use scene. At last, the following concl...Based on the exploring of SWAT model suitability in Hei River Basin, this paper analyze quantitatively and compare non-point source pollution loads occurred under different land use scene. At last, the following conclusion can be attained: (1) Land use change exerts tremendous influence on non-point source pollution. Since forest land can save water and reduce soil loss, which decreases greatly the source of non-point source pollution; (2) Strengthening land management and promoting reasonable land use, especially the over 15 degree slope farmland, will be the effective measure to control non-point source pollution and protect the quality of water in the Hei River basin; (3) The best land use situation in Hei River basin should be like the following modes: complying with national water source protection policy, gradual evacuation of river basin population, returning all the sloping farmland which is above 15 degree to forest land, allowing the existence of few farming land below 15 slope degree on the premise that the drinking water quality standard is reached, no unused land, good vegetation covering situation. At then, total nitrogen load is 13.25 kg, total phosphate load is 3.29 kg, which means it will not contaminate展开更多
Abstract: Excess of organic matter and nutrients in water promotes eutrophication process observed in the Ardila River. It was classified as much polluted being critical for Alqueva-Pedrogāo System. The aim of this ...Abstract: Excess of organic matter and nutrients in water promotes eutrophication process observed in the Ardila River. It was classified as much polluted being critical for Alqueva-Pedrogāo System. The aim of this study was to estimate the transported nutrients loads in a transboundary watershed using the SWAT (soil and water assessment tool) model and to determine the contribution of nutrients load in the entire watershed. Ardila watershed is about 3,711 km^2 extended from Spain (78%) to the eastern part of Portugal (22%). It was discretized into 32 sub-basins using automated delineation routine, and 174 hydrologic response units. Monthly average meteorological data (from 1947 to 1998) were used to generate daily values through the weather generator Model incorporated in SWAT. Real daily precipitation (from 1931 to 2003) was introduced. The model was calibrated and verified for flow (from 1950 to 2000) and nutrients (from 1981 to 1999). Model performance was evaluated using statistical parameters, such as NSE (Nash-Sutcliffe efficiency) and root mean square error (R2). Calibration and verification flow results showed a satisfactory agreement between simulated and measured monthly date from 1962 to 1972 (NSE = 0.8; R^2 = 0.9). The results showed that the most important diffuse pollution comes from the two the main tributary (Spain). The estimated nitrogen and phosphorous loads contribution per year was respectively 72% and 59% in Spain and 28% and 41% in Portugal. The SWAT model was revealed to be a useful tool for an integrated water management approach that might be improved taking into count the WFD (water framework directive).展开更多
Non-point-source pollution has become a major threat to the water quality of the Three Gorges Reservoir(TGR);however,nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring.A represe...Non-point-source pollution has become a major threat to the water quality of the Three Gorges Reservoir(TGR);however,nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring.A representative small watershed in the central part of the TGR area was selected to monitor the loss of nitrogen(N) and phosphorous(P) continuously along with the runoff from 2007 through 2009 to understand the exact sources and loadings.Results show that the non-point-source nitrogen and phosphorus comes mainly from the storm runoff from residential areas,citrus orchards and sloping croplands,which contributes up to 76% of the loadings in this watershed.Thus,a crucial measure for controlling non-point-source pollution is to intercept storm runoff from the three sources.Paddy fields provide a sink for non-point-source N and P by intercepting the runoff and sediment along with their different forms of nitrogen and phosphorus.The N and P removal efficiency by paddy fields from residential areas is within the range of 56% to 98%.Paddy fields are an important land-use option for reducing the non-point-source loading of N and P in the TGR area.展开更多
Gross pollutants are the primary targeted pollutants in urban catchment management for urban water quality improvement as well as mitigation of flood. Apart from aesthetically unattractive because of its visibility, g...Gross pollutants are the primary targeted pollutants in urban catchment management for urban water quality improvement as well as mitigation of flood. Apart from aesthetically unattractive because of its visibility, gross pollutants also contributes to degradation of river water quality and loss of aquatic habitat as it carries harmful pollutants such as oxygen demanding material, hydrocarbons and heavy metals. This study analyzed trend of gross pollutant generated from two urban residential areas located in Selangor, Malaysia. The median value of gross pollutant load obtained fi'om the Amanah Apartment and Bandar Botanic are 347.41 kg/ha/year and 32.46 kg/ha/year, respectively. Relationship between gross pollutant wet load with rainfall depths was derived using regression equation. A significant trend of increasing gross pollutant wet load into drainage system with increasing rainfall depth was observed. The behavior of pollutant load is related to the one observed in Australia.展开更多
Recent improvements to sewerage systems have meant that the relative contribution of point sources of pollution to the overall pollutant loads of streams has decreased markedly. Consequently, the potential increase in...Recent improvements to sewerage systems have meant that the relative contribution of point sources of pollution to the overall pollutant loads of streams has decreased markedly. Consequently, the potential increase in non-point source pollution means that it may be necessary to focus more on pollution loads from non-point sources in the future. This study examined pollution loads from non-point sources in streams flowing through forested areas. In addition, the relationship between runoff and pollution loads was also clarified. The small streams in the Tohoku University Botanical Gardens, in Sendai city, Japan, were sampled during a dry weather period and their water quality parameters were characterized. Chemical Oxygen Demand (COD) concentration increased with distance downstream, possibly because the soils in downstream areas contained high amounts of organic matter. Conversely, the concentration of nitrate nitrogen (NO3-N) decreased with distance downstream, probably because upstream soils were generally in an oxidized state while those further downstream were reduced. COD concentration increased with air temperature, while NO3-N levels decreased with an increase in air temperatures.展开更多
Two-dimensional/two-dimensional(2D/2D)hybrid nanomaterials have triggered extensive research in the photocatalytic field.The construction of emerging 2D/2D heterostructures can generate many intriguing advantages in e...Two-dimensional/two-dimensional(2D/2D)hybrid nanomaterials have triggered extensive research in the photocatalytic field.The construction of emerging 2D/2D heterostructures can generate many intriguing advantages in exploring high-performance photocatalysts,mainly including preferable dimensionality design allowing large contact interface area,integrated merits of each 2D component and rapid charge separation by the heterojunction effect.Herein,we provide a comprehensive review of the recent progress on the fundamental aspects,general synthesis strategies(in situ growth and ex situ assembly)of 2D/2D heterostructured photocatalysts and highlight their applications in the fields of hydrogen evolution,CO2 reduction and removal of pollutants.Furthermore,the perspectives on the remaining challenges and future opportunities regarding the development of 2D/2D heterostructure photocatalysts are also presented.展开更多
基金The National Science and Technology Major Project of China(No.2008ZX07317-001)
文摘In order to improve water quality of middle ancient canal in Zhenjiang city a pollution control project was carried out.The research area is the middle catchment area of the ancient canal river system in the old town of Zhenjiang. The specific research object is the runoff of the outfall of rainwater-sewage confluence in the area. On the basis of detecting and analyzing the water yield and water quality of the runoff of rainwater-sewage confluence a combined technology which contains four independent continuous processes for lowering pollution load was developed and system equipment was established and put into operation. The processing effects of the project were monitored and analyzed.The results show that the pollution control project of outfall runoff is efficient which decreases the pollution load including chemical oxygen demand COD total phosphorus TP suspended solids SS and ammonia-nitrogen NH3-N .As a result the water environment of the ancient canal is protected.
文摘AIM: To characterize the peripheral T-cell subpopulation profiles and their correlation with hepatitis B virus (HBV) replication in different dinical stages of chronic HBV infection. METHODS: A total of 422 patients with chronic HBV infection were enrolled in this study. The patients were divided into three stages: immune-tolerant stage, immune active stage, and immune-inactive carrier stage. Composition of peripheral T-cell subpopulations was determined by flow cytometry. HBV markers were detected by enzyme-linked immunosorbent assay. Serum HBV DNA load was assessed by quantitative real-time poiymerase chain reaction.RESULTS: CD8^+ T-cells were significantly higher in patients at the immune-tolerant stage than in patients at the immune-active and -inactive carrier stages (36.87 ± 7.58 vs 34.37 ± 9.07, 36.87 ± 7.58 vs 28.09 ± 5.64, P 〈 0.001). The peripheral blood in patients at the immune-tolerant and immune active stages contained more CD8^+ T-cells than CD4^+ T-cells (36.87 ± 7.58 vs 30.23 ± 6.35, 34.37 ± 9.07 vs 30.92 ± 7.40, P 〈 0.01), whereas the peripheral blood in patients at the immune- inactive carrier stage and in normal controls contained less CD8^+ T-cells than CD4^+ T-cells (28.09 ± 5.64 vs 36.85 ±6.06, 24.02 ± 4.35 vs 38.94 ± 3.39, P 〈 0.01). ANOVA linear trend test showed that CD8^+ T-cells were significantly increased in patients with a high viral load (39.41 ± 7.36, 33.83 ± 7.50, 31.81 ± 5.95 and 26.89 ± 5.71, P 〈 0.001), while CD4^+ T-cells were significantly increased in patients with a low HBV DNA load (37.45 ± 6.24, 33.33 ± 5.61, 31.58 ± 6.99 and 27.56 ± 5.49, P 〈 0.001). Nultiple regression analysis displayed that log copies of HBV DNA still maintained its highly significant coefficients for T-cell subpopulations, and was the strongest predictors for variations in CD3^+, CD4^+ and CD8^+ cells and CD4^+/CD8^+ ratio after adjustment for age at HBV-infection, maternal HBV-infection status, presence of hepatitis B e antigen and HBV mutation.CONCLUSION: Differences in peripheral T-cell subpopulation profiles can be found in different clinical stages of chronic HBV infection. T-cell impairment is significantly associated with HBV load.
基金Supported by the Major Projects on Control and Rectification of Water Body Pollution (No. 2008ZX07101-012)the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX1-YW14)+1 种基金the Aquaculture "three projects" of Jiangsu (No. J2009-12)the Agricultural Basic Research Fund of Suzhou (No. YJG0912)
文摘To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake, China, we studied water quality and nutrient budget in Chinese mitten crab (Eriocheir sinensis) farm ponds in the eastern part of the lake from November 2007 to December 2009. We estimated the nitrogen (N), phosphorus (P), and chemical oxygen demand (COD) loads. Materials input and output ponds, water exchange, and applied management practices of 838.5-hm2 crab ponds were surveyed using questionnaires. Water quality of 12 ponds, which were located no more than 2 km from East Taihu Lake, were monitored. The results show that water quality in the crab ponds was better than reference data. Feeds, including corn seed, commercial feed, trash fish, and gastropod, were the major sources of N and P input in the crab ponds, contributing 88.7% and 94.9%, respectively. In total, 60.5% of N and 37.3% of P were sequestered by macrophytes, and only 15.7% and 8.5% of them were discharged as effluent. The net loads of N and P in effluent were 16.43 kg/hm2/cycle and 2.16 kg/hm2/cycle, respectively, while the COD load was -17.88 kg/hm2/cycle. This indicated that crab farming caused minor negative impact on the trophic status of the lake area, which was attenuated by macrophytes. However, wastewater purification is still necessary in crab faming.
文摘This study estimated pollutant load from Kahuwa micro-catchment into Lake Kivu. The micro-catchment was sampled monthly for a year at six locations to capture the contribution of agricultural land, industries and commercial blocks. Both wet and dry depositions in terms of TN (total nitrogen) and TP (total phosphorus) were estimated monthly. The level of pollution was estimated using LISEC index and IPO (organic pollution indices). Results show that Kahuwa River micro-catchment is polluted mainly by waste dumping sites and industries within the micro-catchment. The general load to the outlet was respectively about 0.35 tons per year (t/yr) for BODs, 1.9 t/yr for COD, 32.73 t/yr for TP and 224.37 t/yr for TN. Atmospheric deposition of nutrient contributed for about 4% and 18% of TP, 3% and 0.01% of TN during dry and wet deposition, respectively.
文摘The key objective of this research was to estimate the Ni and Cr contents of soil around the Baghjar Chromite Mine(BCM)of Sabzevar Ophiolite Belt,Northeastern Iran,and assess the degree of soil pollution using the pollution indices.Soil samples(0-20 cm depth) were collected at various distances from the BCM.In the present research,heavy metals(Cr and Ni) in soil samples were analyzed by atomic absorption spectrometry to detect their concentrations and contour maps were produced to explain the metal spatial distribution.Also,the degree of metal pollution was quantified.The results indicate that the soils in the studied area are contaminated by Cr and Ni.The corresponding concentrations for Cr and Ni are(156.19±24.45) and(321.7±133.27) mg/kg,respectively,which exceed the corresponding maximum allowable concentrations in soils.The different indices demonstrate that soils around chromite mine are significantly contaminated with Cr and Ni,suggesting several times higher levels of toxic metals than normal ranges.The above results revealed that the heavy metal concentrations increase with increasing the distance from the mine and mining pollutants can be transported to long distances from their sources.
基金Under the auspices of National Natural Science Foundation of China(No.41171155,40801069)National Science and Technology Major Project of China:Water Pollution Control and Governance(No.2012ZX07505-003)
文摘Non-point source(NPS) pollution has become a major source of water pollution. A combination of models would provide the necessary direction and approaches designed to control NPS pollution through land use planning. In this study, NPS pollution load was simulated in urban planning, historic trends and ecological protection land use scenarios based on the Conversion of Land Use and its Effect at Small regional extent(CLUE-S) and Soil and Water Assessment Tool(SWAT) models applied to Hunhe-Taizi River Watershed, Liaoning Province, China. Total nitrogen(TN) and total phosphorus(TP) were chosen as NPS pollution indices. The results of models validation showed that CLUE-S and SWAT models were suitable in the study area. NPS pollution mainly came from dry farmland, paddy, rural and urban areas. The spatial distribution of TN and TP exhibited the same trend in 57 sub-catchments. The TN and TP had the highest NPS pollution load in the western and central plains, which concentrated the urban area and farm land. The NPS pollution load would increase in the urban planning and historic trends scenarios, and would be even higher in the urban planning scenario. However, the NPS pollution load decreased in the ecological protection scenario. The differences observed in the three scenarios indicated that land use had a degree of impact on NPS pollution, which showed that scientific and ecologically sound construction could effectively reduce the NPS pollution load in a watershed. This study provides a scientific method for conducting NPS pollution research at the watershed scale, a scientific basis for non-point source pollution control, and a reference for related policy making.
基金This work was supported by the National Natu- ral Science Foundation of China (No.21072152 and No.21101115).
文摘Developing photosensitizers suitable for the cobalt electrolyte and understanding the structure-property relationship of organic dyes is warranted for the dye-sensitized solar cells (DSSCs). The DSSCs incorporating tris(1,10-phenanthroline)eobalt(Ⅱ/Ⅲ)-based redox elec- trolyte and four synthesized organic dyes as photosensitizers are described. The photovoltaic performance of these dyes-sensitized solar cells employing the cobalt redox shuttle and the influences of the w-conjugated spacers of organic dyes upon the photovoltage and photocur- rent of mesoscopic titania solar cells are investigated. It is found that organic dyes with thiophene derivates as linkers are suitable for DSSCs employing cobalt electrolytes. DSSCs sensitized with the as-synthesized dyes in combination with the cobalt redox shuttle yield an overall power conversion efficiency of 6.1% under 100 mW/cm2 AM1.5 G illumination.
文摘With the current tightening of environmental regulations of waste water treatment, there is a need for the enhancement of the treatment efficiency. This can be done through process changes, or by adding a finishing treatment after the process, like flotation or filtration. Wetlands are also one possibility for the finishing treatment of waste water. In Finland Wetlands have been used as a polishing treatment for municipal wastewater for approx. 20 years. Most of these are natural wetlands. Using wetlands after efficient wastewater treatment is an economical way of producing high quality treated water and cutting down the pollution load of water bodies. Wetlands have also been used in the control of diffuse pollution in agriculture and forestry.
基金This study was supported by the project of National Natural Science Foundation of china (No. 90610030).
文摘Based on the exploring of SWAT model suitability in Hei River Basin, this paper analyze quantitatively and compare non-point source pollution loads occurred under different land use scene. At last, the following conclusion can be attained: (1) Land use change exerts tremendous influence on non-point source pollution. Since forest land can save water and reduce soil loss, which decreases greatly the source of non-point source pollution; (2) Strengthening land management and promoting reasonable land use, especially the over 15 degree slope farmland, will be the effective measure to control non-point source pollution and protect the quality of water in the Hei River basin; (3) The best land use situation in Hei River basin should be like the following modes: complying with national water source protection policy, gradual evacuation of river basin population, returning all the sloping farmland which is above 15 degree to forest land, allowing the existence of few farming land below 15 slope degree on the premise that the drinking water quality standard is reached, no unused land, good vegetation covering situation. At then, total nitrogen load is 13.25 kg, total phosphate load is 3.29 kg, which means it will not contaminate
文摘Abstract: Excess of organic matter and nutrients in water promotes eutrophication process observed in the Ardila River. It was classified as much polluted being critical for Alqueva-Pedrogāo System. The aim of this study was to estimate the transported nutrients loads in a transboundary watershed using the SWAT (soil and water assessment tool) model and to determine the contribution of nutrients load in the entire watershed. Ardila watershed is about 3,711 km^2 extended from Spain (78%) to the eastern part of Portugal (22%). It was discretized into 32 sub-basins using automated delineation routine, and 174 hydrologic response units. Monthly average meteorological data (from 1947 to 1998) were used to generate daily values through the weather generator Model incorporated in SWAT. Real daily precipitation (from 1931 to 2003) was introduced. The model was calibrated and verified for flow (from 1950 to 2000) and nutrients (from 1981 to 1999). Model performance was evaluated using statistical parameters, such as NSE (Nash-Sutcliffe efficiency) and root mean square error (R2). Calibration and verification flow results showed a satisfactory agreement between simulated and measured monthly date from 1962 to 1972 (NSE = 0.8; R^2 = 0.9). The results showed that the most important diffuse pollution comes from the two the main tributary (Spain). The estimated nitrogen and phosphorous loads contribution per year was respectively 72% and 59% in Spain and 28% and 41% in Portugal. The SWAT model was revealed to be a useful tool for an integrated water management approach that might be improved taking into count the WFD (water framework directive).
基金supported by the National Science & Technology Pillar Program(Grant No. 2011BAD31B03)the Special Project on Water Pollution Control by the National Science & Technology Pillar Program(Grant No. 2009ZX07104-002)
文摘Non-point-source pollution has become a major threat to the water quality of the Three Gorges Reservoir(TGR);however,nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring.A representative small watershed in the central part of the TGR area was selected to monitor the loss of nitrogen(N) and phosphorous(P) continuously along with the runoff from 2007 through 2009 to understand the exact sources and loadings.Results show that the non-point-source nitrogen and phosphorus comes mainly from the storm runoff from residential areas,citrus orchards and sloping croplands,which contributes up to 76% of the loadings in this watershed.Thus,a crucial measure for controlling non-point-source pollution is to intercept storm runoff from the three sources.Paddy fields provide a sink for non-point-source N and P by intercepting the runoff and sediment along with their different forms of nitrogen and phosphorus.The N and P removal efficiency by paddy fields from residential areas is within the range of 56% to 98%.Paddy fields are an important land-use option for reducing the non-point-source loading of N and P in the TGR area.
文摘Gross pollutants are the primary targeted pollutants in urban catchment management for urban water quality improvement as well as mitigation of flood. Apart from aesthetically unattractive because of its visibility, gross pollutants also contributes to degradation of river water quality and loss of aquatic habitat as it carries harmful pollutants such as oxygen demanding material, hydrocarbons and heavy metals. This study analyzed trend of gross pollutant generated from two urban residential areas located in Selangor, Malaysia. The median value of gross pollutant load obtained fi'om the Amanah Apartment and Bandar Botanic are 347.41 kg/ha/year and 32.46 kg/ha/year, respectively. Relationship between gross pollutant wet load with rainfall depths was derived using regression equation. A significant trend of increasing gross pollutant wet load into drainage system with increasing rainfall depth was observed. The behavior of pollutant load is related to the one observed in Australia.
文摘Recent improvements to sewerage systems have meant that the relative contribution of point sources of pollution to the overall pollutant loads of streams has decreased markedly. Consequently, the potential increase in non-point source pollution means that it may be necessary to focus more on pollution loads from non-point sources in the future. This study examined pollution loads from non-point sources in streams flowing through forested areas. In addition, the relationship between runoff and pollution loads was also clarified. The small streams in the Tohoku University Botanical Gardens, in Sendai city, Japan, were sampled during a dry weather period and their water quality parameters were characterized. Chemical Oxygen Demand (COD) concentration increased with distance downstream, possibly because the soils in downstream areas contained high amounts of organic matter. Conversely, the concentration of nitrate nitrogen (NO3-N) decreased with distance downstream, probably because upstream soils were generally in an oxidized state while those further downstream were reduced. COD concentration increased with air temperature, while NO3-N levels decreased with an increase in air temperatures.
基金financially supported by the Australia Research Council(ARC DP 180102062)the National Natural Science Foundation of China(51602163)。
文摘Two-dimensional/two-dimensional(2D/2D)hybrid nanomaterials have triggered extensive research in the photocatalytic field.The construction of emerging 2D/2D heterostructures can generate many intriguing advantages in exploring high-performance photocatalysts,mainly including preferable dimensionality design allowing large contact interface area,integrated merits of each 2D component and rapid charge separation by the heterojunction effect.Herein,we provide a comprehensive review of the recent progress on the fundamental aspects,general synthesis strategies(in situ growth and ex situ assembly)of 2D/2D heterostructured photocatalysts and highlight their applications in the fields of hydrogen evolution,CO2 reduction and removal of pollutants.Furthermore,the perspectives on the remaining challenges and future opportunities regarding the development of 2D/2D heterostructure photocatalysts are also presented.