Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 mz was constructed on...Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 mz was constructed on an egg duck farm, and water hyacinth （Eichhornia crassipes） was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks＇ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand （COD）, 21.78% of total nitrogen （TN） and 23.02% of total phosphorus （TP）. Both dissolved oxygen （DO） and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the differences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group （P 〈 0.05）, but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth. We concluded that a water hyacinth system was effective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.展开更多
Objective: This study was to assess the influence of interaction of combination of immobilized nitrogen cycling bacteria (INCB) with aquatic macrophytes on nitrogen removal from the eutrophic waterbody, and to get ins...Objective: This study was to assess the influence of interaction of combination of immobilized nitrogen cycling bacteria (INCB) with aquatic macrophytes on nitrogen removal from the eutrophic waterbody, and to get insight into different mechanisms involved in nitrogen removal. Methods: The aquatic macrophytes used include Eichhornia crassipes (sum-mer-autumn floating macrophyte), Elodea nuttallii (winter-growing submerged macrophyte), and nitrogen cycling bacteria in-cluding ammonifying, nitrosating, nitrifying and denitrifying bacteria isolated from Taihu Lake. The immobilization carriers materials were made from hydrophilic monomers 2-hydroxyethyl acrylate (HEA) and hydrophobic 2-hydroxyethyl methylacrylate (HEMA). Two experiments were conducted to evaluate the roles of macrophytes combined with INCB on nitrogen removal from eutrophic water during different seasons. Results: Eichhornia crassipes and Elodea nuttallii had different potentials in purification of eutrophic water. Floating macrophyte+bacteria (INCB) performed best in improving water quality (during the first experiment) and decreased total nitrogen (TN) by 70.2%, nitrite and ammonium by 92.2% and 50.9%, respectively, during the experimental period, when water transparency increased from 0.5 m to 1.8 m. When INCB was inoculated into the floating macrophyte system, the populations of nitrosating, nitrifying, and denitrifying bacteria increased by 1 to 2 orders of magnitude compared to the un-inoculated treatments, but ammonifying bacteria showed no obvious difference between different treatments. Lower values of chlorophyll a, CODMn, and pH were found in the microbial-plant integrated system, as compared to the control. Highest reduction in N was noted during the treatment with submerged macrophyte+INCB, being 26.1% for TN, 85.2% for nitrite, and 85.2% for ammonium at the end of 2nd experiment. And in the treatment, the populations of ammonifying, nitrosating, nitrifying, and de-nitrifying bacteria increased by 1 to 3 orders of magnitude, as compared 展开更多
From 20 January to 20 July 2023, a study was carried out on the Lobé Creek, a waterway subject to considerable natural and man-made pressures, with a negative impact on its biodiversity and habitats. The aim was ...From 20 January to 20 July 2023, a study was carried out on the Lobé Creek, a waterway subject to considerable natural and man-made pressures, with a negative impact on its biodiversity and habitats. The aim was to evaluate the growth rate of invasive aquatic macrophytes and their contribution to the use of organic fertilisers: a case of Eicchornia crassipes (Mart.) Solms, 1883 in the Lobé Creek (Littoral-Cameroon) with a view to its appropriate use in agronomy. The specific objective was to examine the impact of anthropogenic actions on Lobé Creek, characterise physico-chemical environment of the study area, and evaluate the growth rate of E. crassipes and its chemical composition with a view to producing an organic biofertiliser. The results show that E. crassipes represents a considerable threat to the populations of these localities. As for the physico-chemical parameters, the temperature values vary from 24 ± 1.41˚C to 26.5 ± 1.13˚C;pH from 6.3 ± 0.1 to 7.2 ± 0.07;conductivity and dissolved oxygen vary respectively from 40.7 ± 1.83 µS/cm to 19.6 ± 3.11 µS/cm and from 7.3 ± 0.14 mg/l to 5.8 ± 1.55 mg/l. Its average growth rate varies from 0.69 feet/day to 0.63 feet/day. With regard to the nitrogen, phosphorus and potassium content of water hyacinth plants, the results show that the average total nitrogen content ranges from 6.11 ± 1.59 g/kg to 5.2 ± 2.03 g/kg;total phosphorus, from 0.52 ± 0.54 g/kg to 0.88 ± 0.38 g/kg;and potassium, from 1.43 ± 0.45 g/kg to 2.61 ± 0.89 g/kg.展开更多
Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental ch...Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental challenges. Currently the weed is harvested from the Lake and left in the open to rot and decay leading to loss of aesthetics, land and air pollution. There is therefore need for development of value addition and economic exploitation strategies. The aim of the study is to assess the potential for utilization of the weed as a renewable energy resource for biogas production. Samples were collected from Lake Victoria, pulped and blend with cow dung at a ratio of 3:1 as inoculum. The resultant mixture was mixed with water at a ratio of 1:1 and fed into a 6 m3 tubular digester. The digester was recharged with 20 kg after every three days. The temperature, pH variations, gas compositions, upgrading and gas yields were studied. The temperature ranged between 22.8°C - 36.6°C and pH 7.4 - 8.5. Biogas was found to contain 49% - 53% methane (CH4 ), 30% - 33% carbon dioxide (CO2 ), 5% - 6% nitrogen (N2 ) and traces of hydrogen sulphide (H2S). The biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content by up to 70% - 76%. The upgraded gas was used to power internal combustion engines coupled with an electricity generator and direct heat applications. The study concludes that E. crassipes is a potential feedstock for biogas production especially in areas where it is abundant.展开更多
Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects of pollutants from textile wastewater on the anatomy...Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects of pollutants from textile wastewater on the anatomy of the plant were studied. Water hyacinth exhibits hydrophytic adaptations which include reduced epidermis cells lacking cuticle in most cases, presence of large air spaces (7～50 μm), reduced vascular tissue and absorbing structures. Textile waste significantly affected the size of root cells.The presence of raphide crystals was noted in parenchyma cells of various organs in treated plants.展开更多
Eichhornia crassipes is a hyperaccumulator of metals and has been widely used to remove metal pollutants from water, but disposal of contaminated plants is problematic.Biochar prepared from plants is commonly used to ...Eichhornia crassipes is a hyperaccumulator of metals and has been widely used to remove metal pollutants from water, but disposal of contaminated plants is problematic.Biochar prepared from plants is commonly used to remediate soils and sequester carbon.Here, the catalytic activity of biochar prepared from plants enriched with iron was investigated as a potentially beneficial use of metal-contaminated plants.In a 30-day hydroponic experiment, E.crassipes was exposed to different concentrations of Fe(Ⅲ)(0, 4, 8, 16, 32 and 64 mg/L), and Fe-biochar(Fe-BC) was prepared by pyrolysis of the plant roots.The biochar was characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive X-ray spectrometry(EDS), Brunauer–Emmett–Teller(BET) analysis, X-ray photoelectron spectroscopy(XPS) and atomic absorption spectrometry(AAS).The original root morphology was visible and iron was present as γ-Fe2O3 and Fe3O4.The biochar enriched with Fe(Ⅲ) at 8 mg/L(8-Fe-BC) had the smallest specific surface area(SSA, 13.54 m^2/g) and the highest Fe content(27.9 mg/g).Fe-BC catalytic activity was tested in the electrocatalytic reduction of H2O2 using cyclic voltammetry(CV).The largest reduction current(1.82 mA/cm^2) was displayed by 8-Fe-BC, indicating the highest potential catalytic activity.We report here, for the first time, on the catalytic activity of biochar made from iron-enriched plants and demonstrate the potential for reusing metalcontaminated plants to produce a biochar catalyst.展开更多
Neochetina eichhorniae and Neochetina bruchi have been used for over four decades as Eichhorniae crassipes classical biological control agents globally. Despite the success of bio-control against the water hyacinth gl...Neochetina eichhorniae and Neochetina bruchi have been used for over four decades as Eichhorniae crassipes classical biological control agents globally. Despite the success of bio-control against the water hyacinth globally at different levels and environmental sustainability, biological control against water hyacinth seems to have overlooked the socio-economic sustainability in assisting the ravaged communities, gain resilience and adapt to the challenges of the invasive alien species. This manuscript evaluates the potential to draw out more from biological control of the water hyacinth by evaluating the potential to utilize Neochetina eichhorniae and Neochetina bruchi as feed. The live insects of the two species were collected from the water hyacinth marts in the nearby L. Victoria in Siaya county, Kenya. Where they were then transferred for semi-cultivation in localized ponds for reproduction and closer monitoring. The ponds having been set up in completely randomized design while in the open within the same climatic region mimicked the water quality and most abiotic conditions of the lake necessary for the insects’ and host plant acclimatization and reproduction. The samples for proximate analysis were collected from these ponds as per the research and experimental design. The chemical compositions of the Neochetina bruchi, N. eichhorniae and their larvae composite, satisfactorily compared to basic fish feed requirements, specifically as a protein source having crude protein (CP) percentage per DM of 55.0350 ± 0.025, 54.4350 ± 0.035 and 62.2750 ± 0.025 respectively.展开更多
At present, sensitive material factories and various cinefilm processing factories can only treat silver-containing waste water of high concentration, and have difficulties in dealing with the waste water of silver co...At present, sensitive material factories and various cinefilm processing factories can only treat silver-containing waste water of high concentration, and have difficulties in dealing with the waste water of silver concentration lower than 2-3 mg/1. Therefore the loss of silver is relatively large. This not only leads to a great economic loss, but also brings about seri-展开更多
The aim of this study was to evaluate the herbicide glyphosate under aquatic environment conditions, in a controlled and closed experimental field, in the management of water hyacinth (Eichhornia crassipes) in reservo...The aim of this study was to evaluate the herbicide glyphosate under aquatic environment conditions, in a controlled and closed experimental field, in the management of water hyacinth (Eichhornia crassipes) in reservoirs. Twenty reservoirs (polyethylene water tanks) with storage capacity of 1000 liters were used, without water flow and without evapotranspired water replacement (worst case), being 04 for each treatment. The adult plants were placed in the water tanks to provide 90% surface occupation of the reservoir. Five treatments with four repetitions were considered, being: 1) Reservoir colonized by water hyacinth without control;2) Reservoir colonized by water hyacinth, controlled by glyphosate;3) Reservoir colonized by water hyacinth, controlled by freezing;4) Reservoir without water hyacinth and glyphosate application and 5) Reservoir without water hyacinth and no glyphosate application. The glyphosate herbicide was used at the highest recommended dose, 7.0 L·ha-1 or 3360 g of acid equivalent per ha, applied using carbon dioxide precision equipment (backpack sprayer), providing a flow rate of 200 L·ha-1. The water samples were collected at the time of application, 6, 12, 18 and 24 hours after application and also at 2, 4, 8, 16, 32 and 64 days after application, in the morning, always at the same time, also between 8 and 9 h. The method used for determination of residues was by high performance liquid chromatography (HPLC) and mass spectrometry with a mass selective detector. Low concentrations of glyphosate and aminomethylphosphonic acid (AMPA) were found in both reservoirs that received application of the product. The half-life of glyphosate in water to the reservoirs with water hyacinth was 11 days and in the reservoirs without water hyacinth was 21 days. The results show a low potential of environmental impact of glyphosate use in the control of water hyacinth in reservoirs.展开更多
Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and w...Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and water quality of the pond loach Misgurnus anguillicaudatus in three scenarios:in tanks without plants,tanks with the free-floating plant water hyacinth Eichhornia crassipes,and tanks with water lettuce Pistia stratiotes.Water hyacinth effectively removed water TN,COD,NO3-N and NH4-N,and water lettuce removed water TP and NH4-N.Water hyacinth and water lettuce markedly reduced water turbidity and DO,increased TOC and EC.Water hyacinth purified water more effectively than water lettuce,providing a suitable habitat for loach feeding,living and burrowing.The burrow structures were V-shaped,Y-shaped,inverted L-shaped,or complicated dendritic networks composed of multiple V shapes.The hyacinth treatment was characterized by the greatest burrow volume,length,depth,and structural complexity,but the opening size was reduced by dense root mat coverage.Burrows in the water lettuce treatment were characterized by intermediate volume,length,branches and sinuosity,but they had the largest opening and pit size.The control treatment had a flat bottom with the smallest,shortest burrows.This study indicates that free-floating plants improve habitat suitability and change burrow morphology and may be used to improve loach breeding methods。展开更多
6 -Hydroxy-stigmasta-4,22-diene-3-one 1,a novel steroid, was isolated from the Eichhornia Crassipes.Its structure was deter- mined by ~1H and ^(13)C NMR spectroscopy and further confirmed by authen- tic sample,which w...6 -Hydroxy-stigmasta-4,22-diene-3-one 1,a novel steroid, was isolated from the Eichhornia Crassipes.Its structure was deter- mined by ~1H and ^(13)C NMR spectroscopy and further confirmed by authen- tic sample,which was synthesized from stigmasterol 2.展开更多
The potential of water hyacinth—Eichhornia crassipes biomass immobilized in calcium alginate for the adsorption of Ni(II) from water was studied using the Langmuir and Freundlich adsorption models. The equilibrium ad...The potential of water hyacinth—Eichhornia crassipes biomass immobilized in calcium alginate for the adsorption of Ni(II) from water was studied using the Langmuir and Freundlich adsorption models. The equilibrium adsorption data were obtained at different initial Ni(II) concentrations = 0.05-2 mg/L, temperature = 30℃?± 0.2℃, agitation rate = 150 rpm, equilibration time = 3 hr, biosorbent dose =4 g/L, and pH range = 4-7.4. Langmuir isotherms gave monolayer sorption capacities (qm) of 26.5, 44.3 and 53.0 mg/g for the removal of Ni(II) in the presence of methanol, without added organic substance, and in the presence of acetonitrile, respectively. These findings were also confirmed by the trend in the Freundlich isotherm parameter (1/n? 1). Interpretation of the sorption data in terms of the separation factor, SF, suggested that the removal of Ni(II) from water mainly occurred through a chemisorption mechanism. Desorption experiments to recover Ni(II) from the adsorbent showed that highest amounts of the metal could be removed from the adsorbent when previously adsorbed in the presence of 1-(2-Thiazolylazo)-2-naphtol (TAN) (>90%). The results from these studies indicated that E. crassipes fixed on calcium alginate beads is a viable metal enrichment media that can be used freely immersed in solution to achieve very high adsorption capacities and possible preconcentration of Ni(II) in aquatic environments.展开更多
文摘Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 mz was constructed on an egg duck farm, and water hyacinth （Eichhornia crassipes） was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks＇ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand （COD）, 21.78% of total nitrogen （TN） and 23.02% of total phosphorus （TP）. Both dissolved oxygen （DO） and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the differences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group （P 〈 0.05）, but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth. We concluded that a water hyacinth system was effective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.
基金Project supported by the Ministry of Science and Technology of China, the Education Ministry of China (No. 20305), Australia Gov-ernment’s Innovation Statement Backing Australia’s Ability (No. [2002]68), and the Science and Technology Bureau of ZhejiangProvince (No. 2005C22020), China
文摘Objective: This study was to assess the influence of interaction of combination of immobilized nitrogen cycling bacteria (INCB) with aquatic macrophytes on nitrogen removal from the eutrophic waterbody, and to get insight into different mechanisms involved in nitrogen removal. Methods: The aquatic macrophytes used include Eichhornia crassipes (sum-mer-autumn floating macrophyte), Elodea nuttallii (winter-growing submerged macrophyte), and nitrogen cycling bacteria in-cluding ammonifying, nitrosating, nitrifying and denitrifying bacteria isolated from Taihu Lake. The immobilization carriers materials were made from hydrophilic monomers 2-hydroxyethyl acrylate (HEA) and hydrophobic 2-hydroxyethyl methylacrylate (HEMA). Two experiments were conducted to evaluate the roles of macrophytes combined with INCB on nitrogen removal from eutrophic water during different seasons. Results: Eichhornia crassipes and Elodea nuttallii had different potentials in purification of eutrophic water. Floating macrophyte+bacteria (INCB) performed best in improving water quality (during the first experiment) and decreased total nitrogen (TN) by 70.2%, nitrite and ammonium by 92.2% and 50.9%, respectively, during the experimental period, when water transparency increased from 0.5 m to 1.8 m. When INCB was inoculated into the floating macrophyte system, the populations of nitrosating, nitrifying, and denitrifying bacteria increased by 1 to 2 orders of magnitude compared to the un-inoculated treatments, but ammonifying bacteria showed no obvious difference between different treatments. Lower values of chlorophyll a, CODMn, and pH were found in the microbial-plant integrated system, as compared to the control. Highest reduction in N was noted during the treatment with submerged macrophyte+INCB, being 26.1% for TN, 85.2% for nitrite, and 85.2% for ammonium at the end of 2nd experiment. And in the treatment, the populations of ammonifying, nitrosating, nitrifying, and de-nitrifying bacteria increased by 1 to 3 orders of magnitude, as compared
文摘From 20 January to 20 July 2023, a study was carried out on the Lobé Creek, a waterway subject to considerable natural and man-made pressures, with a negative impact on its biodiversity and habitats. The aim was to evaluate the growth rate of invasive aquatic macrophytes and their contribution to the use of organic fertilisers: a case of Eicchornia crassipes (Mart.) Solms, 1883 in the Lobé Creek (Littoral-Cameroon) with a view to its appropriate use in agronomy. The specific objective was to examine the impact of anthropogenic actions on Lobé Creek, characterise physico-chemical environment of the study area, and evaluate the growth rate of E. crassipes and its chemical composition with a view to producing an organic biofertiliser. The results show that E. crassipes represents a considerable threat to the populations of these localities. As for the physico-chemical parameters, the temperature values vary from 24 ± 1.41˚C to 26.5 ± 1.13˚C;pH from 6.3 ± 0.1 to 7.2 ± 0.07;conductivity and dissolved oxygen vary respectively from 40.7 ± 1.83 µS/cm to 19.6 ± 3.11 µS/cm and from 7.3 ± 0.14 mg/l to 5.8 ± 1.55 mg/l. Its average growth rate varies from 0.69 feet/day to 0.63 feet/day. With regard to the nitrogen, phosphorus and potassium content of water hyacinth plants, the results show that the average total nitrogen content ranges from 6.11 ± 1.59 g/kg to 5.2 ± 2.03 g/kg;total phosphorus, from 0.52 ± 0.54 g/kg to 0.88 ± 0.38 g/kg;and potassium, from 1.43 ± 0.45 g/kg to 2.61 ± 0.89 g/kg.
文摘Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental challenges. Currently the weed is harvested from the Lake and left in the open to rot and decay leading to loss of aesthetics, land and air pollution. There is therefore need for development of value addition and economic exploitation strategies. The aim of the study is to assess the potential for utilization of the weed as a renewable energy resource for biogas production. Samples were collected from Lake Victoria, pulped and blend with cow dung at a ratio of 3:1 as inoculum. The resultant mixture was mixed with water at a ratio of 1:1 and fed into a 6 m3 tubular digester. The digester was recharged with 20 kg after every three days. The temperature, pH variations, gas compositions, upgrading and gas yields were studied. The temperature ranged between 22.8°C - 36.6°C and pH 7.4 - 8.5. Biogas was found to contain 49% - 53% methane (CH4 ), 30% - 33% carbon dioxide (CO2 ), 5% - 6% nitrogen (N2 ) and traces of hydrogen sulphide (H2S). The biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content by up to 70% - 76%. The upgraded gas was used to power internal combustion engines coupled with an electricity generator and direct heat applications. The study concludes that E. crassipes is a potential feedstock for biogas production especially in areas where it is abundant.
基金Project (No. 30070017) supported by the National Natural Science Foundation of China
文摘Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects of pollutants from textile wastewater on the anatomy of the plant were studied. Water hyacinth exhibits hydrophytic adaptations which include reduced epidermis cells lacking cuticle in most cases, presence of large air spaces (7～50 μm), reduced vascular tissue and absorbing structures. Textile waste significantly affected the size of root cells.The presence of raphide crystals was noted in parenchyma cells of various organs in treated plants.
基金supported by supported by the National Natural Science Foundation of China (Nos.21677086 and 21577078)Hubei Innovation Group Project (No.2015CFA021)+1 种基金the Hubei Foreign Science and Technology Cooperation Project (No.2018AHB020)Three Gorges University Master’s Thesis Training Fund (No.2018SSPY143).
文摘Eichhornia crassipes is a hyperaccumulator of metals and has been widely used to remove metal pollutants from water, but disposal of contaminated plants is problematic.Biochar prepared from plants is commonly used to remediate soils and sequester carbon.Here, the catalytic activity of biochar prepared from plants enriched with iron was investigated as a potentially beneficial use of metal-contaminated plants.In a 30-day hydroponic experiment, E.crassipes was exposed to different concentrations of Fe(Ⅲ)(0, 4, 8, 16, 32 and 64 mg/L), and Fe-biochar(Fe-BC) was prepared by pyrolysis of the plant roots.The biochar was characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive X-ray spectrometry(EDS), Brunauer–Emmett–Teller(BET) analysis, X-ray photoelectron spectroscopy(XPS) and atomic absorption spectrometry(AAS).The original root morphology was visible and iron was present as γ-Fe2O3 and Fe3O4.The biochar enriched with Fe(Ⅲ) at 8 mg/L(8-Fe-BC) had the smallest specific surface area(SSA, 13.54 m^2/g) and the highest Fe content(27.9 mg/g).Fe-BC catalytic activity was tested in the electrocatalytic reduction of H2O2 using cyclic voltammetry(CV).The largest reduction current(1.82 mA/cm^2) was displayed by 8-Fe-BC, indicating the highest potential catalytic activity.We report here, for the first time, on the catalytic activity of biochar made from iron-enriched plants and demonstrate the potential for reusing metalcontaminated plants to produce a biochar catalyst.
文摘Neochetina eichhorniae and Neochetina bruchi have been used for over four decades as Eichhorniae crassipes classical biological control agents globally. Despite the success of bio-control against the water hyacinth globally at different levels and environmental sustainability, biological control against water hyacinth seems to have overlooked the socio-economic sustainability in assisting the ravaged communities, gain resilience and adapt to the challenges of the invasive alien species. This manuscript evaluates the potential to draw out more from biological control of the water hyacinth by evaluating the potential to utilize Neochetina eichhorniae and Neochetina bruchi as feed. The live insects of the two species were collected from the water hyacinth marts in the nearby L. Victoria in Siaya county, Kenya. Where they were then transferred for semi-cultivation in localized ponds for reproduction and closer monitoring. The ponds having been set up in completely randomized design while in the open within the same climatic region mimicked the water quality and most abiotic conditions of the lake necessary for the insects’ and host plant acclimatization and reproduction. The samples for proximate analysis were collected from these ponds as per the research and experimental design. The chemical compositions of the Neochetina bruchi, N. eichhorniae and their larvae composite, satisfactorily compared to basic fish feed requirements, specifically as a protein source having crude protein (CP) percentage per DM of 55.0350 ± 0.025, 54.4350 ± 0.035 and 62.2750 ± 0.025 respectively.
基金Project supported by the National Natural Science Foundation of China
文摘At present, sensitive material factories and various cinefilm processing factories can only treat silver-containing waste water of high concentration, and have difficulties in dealing with the waste water of silver concentration lower than 2-3 mg/1. Therefore the loss of silver is relatively large. This not only leads to a great economic loss, but also brings about seri-
文摘The aim of this study was to evaluate the herbicide glyphosate under aquatic environment conditions, in a controlled and closed experimental field, in the management of water hyacinth (Eichhornia crassipes) in reservoirs. Twenty reservoirs (polyethylene water tanks) with storage capacity of 1000 liters were used, without water flow and without evapotranspired water replacement (worst case), being 04 for each treatment. The adult plants were placed in the water tanks to provide 90% surface occupation of the reservoir. Five treatments with four repetitions were considered, being: 1) Reservoir colonized by water hyacinth without control;2) Reservoir colonized by water hyacinth, controlled by glyphosate;3) Reservoir colonized by water hyacinth, controlled by freezing;4) Reservoir without water hyacinth and glyphosate application and 5) Reservoir without water hyacinth and no glyphosate application. The glyphosate herbicide was used at the highest recommended dose, 7.0 L·ha-1 or 3360 g of acid equivalent per ha, applied using carbon dioxide precision equipment (backpack sprayer), providing a flow rate of 200 L·ha-1. The water samples were collected at the time of application, 6, 12, 18 and 24 hours after application and also at 2, 4, 8, 16, 32 and 64 days after application, in the morning, always at the same time, also between 8 and 9 h. The method used for determination of residues was by high performance liquid chromatography (HPLC) and mass spectrometry with a mass selective detector. Low concentrations of glyphosate and aminomethylphosphonic acid (AMPA) were found in both reservoirs that received application of the product. The half-life of glyphosate in water to the reservoirs with water hyacinth was 11 days and in the reservoirs without water hyacinth was 21 days. The results show a low potential of environmental impact of glyphosate use in the control of water hyacinth in reservoirs.
基金This study was financially supported by the Natural Science Foundation of the Science and Technology Commission of Shanghai Municipality(Grant No.13ZR1427300)Spark Program of the state ministry of science and technology of China(2015GA680005).
文摘Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and water quality of the pond loach Misgurnus anguillicaudatus in three scenarios:in tanks without plants,tanks with the free-floating plant water hyacinth Eichhornia crassipes,and tanks with water lettuce Pistia stratiotes.Water hyacinth effectively removed water TN,COD,NO3-N and NH4-N,and water lettuce removed water TP and NH4-N.Water hyacinth and water lettuce markedly reduced water turbidity and DO,increased TOC and EC.Water hyacinth purified water more effectively than water lettuce,providing a suitable habitat for loach feeding,living and burrowing.The burrow structures were V-shaped,Y-shaped,inverted L-shaped,or complicated dendritic networks composed of multiple V shapes.The hyacinth treatment was characterized by the greatest burrow volume,length,depth,and structural complexity,but the opening size was reduced by dense root mat coverage.Burrows in the water lettuce treatment were characterized by intermediate volume,length,branches and sinuosity,but they had the largest opening and pit size.The control treatment had a flat bottom with the smallest,shortest burrows.This study indicates that free-floating plants improve habitat suitability and change burrow morphology and may be used to improve loach breeding methods。
文摘6 -Hydroxy-stigmasta-4,22-diene-3-one 1,a novel steroid, was isolated from the Eichhornia Crassipes.Its structure was deter- mined by ~1H and ^(13)C NMR spectroscopy and further confirmed by authen- tic sample,which was synthesized from stigmasterol 2.
文摘The potential of water hyacinth—Eichhornia crassipes biomass immobilized in calcium alginate for the adsorption of Ni(II) from water was studied using the Langmuir and Freundlich adsorption models. The equilibrium adsorption data were obtained at different initial Ni(II) concentrations = 0.05-2 mg/L, temperature = 30℃?± 0.2℃, agitation rate = 150 rpm, equilibration time = 3 hr, biosorbent dose =4 g/L, and pH range = 4-7.4. Langmuir isotherms gave monolayer sorption capacities (qm) of 26.5, 44.3 and 53.0 mg/g for the removal of Ni(II) in the presence of methanol, without added organic substance, and in the presence of acetonitrile, respectively. These findings were also confirmed by the trend in the Freundlich isotherm parameter (1/n? 1). Interpretation of the sorption data in terms of the separation factor, SF, suggested that the removal of Ni(II) from water mainly occurred through a chemisorption mechanism. Desorption experiments to recover Ni(II) from the adsorbent showed that highest amounts of the metal could be removed from the adsorbent when previously adsorbed in the presence of 1-(2-Thiazolylazo)-2-naphtol (TAN) (>90%). The results from these studies indicated that E. crassipes fixed on calcium alginate beads is a viable metal enrichment media that can be used freely immersed in solution to achieve very high adsorption capacities and possible preconcentration of Ni(II) in aquatic environments.
