The present study sampled the intestinal content of healthy and unhealthy Atlantic salmon （Salmo salar L.）, the ambient water of unhealthy fish, and the biofilter material in the recirculating aquaculture system （...The present study sampled the intestinal content of healthy and unhealthy Atlantic salmon （Salmo salar L.）, the ambient water of unhealthy fish, and the biofilter material in the recirculating aquaculture system （RAS） to understand differences in the intestinal microbiota. The V4--V5 regions of the prokaryotic 16S rRNA genes in the samples were analyzed by MiSeq high-throughput sequencing. The fish were adults with no differences in body length or weight. Representative members of the intestinal microbiota were identified. The intestinal microbiota of the healthy fish included Proteobacteria （44.33%）, Actinobacteria （17.89%）, Baeteroidetes （15.25%）, and Firmicutes （9.11%）, among which the families Mierococcaceae and Oxalobacteraceae and genera Sphingomonas, Streptomyces, Pedobacter, Janthinobacterium, Burkholderia, and Balneimonas were most abundant. Proteobacteria （70.46%）, Bacteroidetes （7.59%）, and Firmicutes （7.55%） dominated the microbiota of unhealthy fish, and Chloroflexi （2.71%）, and Aliivibrio and Vibrio as well as genera in the family Aeromonadaceae were most strongly represented. Overall, the intestinal hindgut microbiota differed between healthy and unhealthy fish. This study offers a useful tool for monitoring the health status of fish and for screening the utility of probiotics by studying the intestinal microbiota.展开更多
full understanding of the sources of atmospheric nitrous acid(HONO)in the polluted urban atmosphere re-mains a challenge.In this study,ambient HONO and relevant species were measured during January 2019 at an urban si...full understanding of the sources of atmospheric nitrous acid(HONO)in the polluted urban atmosphere re-mains a challenge.In this study,ambient HONO and relevant species were measured during January 2019 at an urban site in Beijing,China,and a budget analysis of HONO was conducted using a box model combined with field observations.Large nighttime“missing sources”of HONO were identified on heavily polluted days based on traditional sources,which had a significant correlation with the relative humidity,ammonia(NH_(3)),and aerosol surface area,and the promotional effect of NH_(3)for nitrogen dioxide(NO_(2))uptake on the wet aerosol surface was discussed.Then,an updated parameterization scheme for quantifying the enhanced heterogeneous reactions of NO_(2)on aerosol surfaces is proposed,and the missing nighttime sources of HONO could be substantially com-pensated after the new scheme was incorporated.Further evaluation on the contributions of HONO to hydroxyl radicals was conducted,and the authors found that the photolysis of HONO played a dominant role in the primary OH production on the polluted days(78%-90%).The study reveals great potential of an NH3-enhanced uptake coefficient of NO_(2)on the aerosol surface in the nocturnal HONO budget,and highlights the significance of HONO in the strong atmospheric oxidation capability during episodes with a heavily polluted atmosphere.展开更多
Biofilms mediate crucial biochemical processes in aquatic ecosystems. It was hypothesized that eutrophication may promote the growth of biofilms, resulting in larger numbers of functional genes. However, the metabolic...Biofilms mediate crucial biochemical processes in aquatic ecosystems. It was hypothesized that eutrophication may promote the growth of biofilms, resulting in larger numbers of functional genes. However, the metabolic activity and the roles of biofilms in N cycling will be affected by ambient inorganic nitrogen availability, not by the abundance of functional genes. Biofilms were cultured either with replete inorganic nitrogen(N-rep) or without exogenous inorganic nitrogen supply(N-def) in a flow incubator, and the N-cycling gene abundances(nifH, N_2 fixation; amoA, ammonia oxidation, archaea and bacteria; nirS and nirK, denitrification) and enzyme activities(nitrogenase and nitrate reductase) were analyzed. The results showed that, comparing the N-def and N-rep biofilms, the former contained lower nifH gene abundance, but higher nitrogenase activity(NA), while the latter contained higher nifH gene abundance, but lower NA. Different patterns of NA diel variations corresponded to the dynamic microbial community composition and different stages of biofilm colonization. Ammonia oxidizing bacteria(AOB), detected only in N-def biofilms, were responsible for nitrification in biofilms. N-rep biofilms contained high nirS and nirK gene abundance and high denitrification enzyme activity, but N-def biofilms contained significantly lower denitrification gene abundance and activity. In general,the strong N_2 fixation in N-def biofilms and strong denitrification in N-rep biofilms assured the balance of aquatic ecosystems. The results suggested that evaluation of the functional processes of N cycling should not only focus on genetic potential, but also on the physiological activity of biofilms.展开更多
Biomarkers in higher plants played an important role to estimate exposure effects of pollutants in soil ecosystem and have received increasing attention in recent years. The qualitative and quantitative modifications ...Biomarkers in higher plants played an important role to estimate exposure effects of pollutants in soil ecosystem and have received increasing attention in recent years. The qualitative and quantitative modifications arising in amplified fragment length polymorphism （AFLP） profiles as a measure of DNA effects were compared with a number of parameters, namely, the root length, total soluble protein content in root tips, chlorophylls content and shoot size to select the most sensitive biomarker responding to copper stress in the range of 0--600 mg/kg. The changes occurring in AFLP profiles of root tips following Cu treatment included loss of normal bands and appearance of new bands and variation in band intensity in comparison to that of the normal seedlings, A reduction in root length was observed at the 200 mg/kg of copper, which was accompanied with a decrease in total soluble protein content. According to their sensitivity to the copper toxicity, the above indicator rank in the following order： AFLP profiles 〉 total soluble protein content 〉 root length 〉 chlorophylls content 〉 shoot. We concluded that the AFLP offered a useful alternative hiomarker assay for the detection of genotoxic effects of environmental pollutants.展开更多
A reverse osmosis （RO） desalination system coupled with tidal energy is proposed. The mechanical energy produced by the tidal energy through hydraulic turbine is directly used to drive the RO unit. The system perfor...A reverse osmosis （RO） desalination system coupled with tidal energy is proposed. The mechanical energy produced by the tidal energy through hydraulic turbine is directly used to drive the RO unit. The system performances and the water cost of the conventional and tidal energy RO systems are compared. It is found that the proposed tidal energy RO system can save water cost in the range of 31.0%-41.7% in comparison with the conventional RO system. There is an optimum feed pressure that leads to the lowest water cost. The tidal RO system can save more costs at a high feed pressure or a high water recovery rate. The optimum feed pressure of the tidal energy RO system is higher than that of the conventional RO system. The longer lifetime of the tidal energy RO system can save even more water cost. When the site development cost rate is lower than 40%, the water cost of the tidal energy RO system will be lower than that of the conventional RO system. The proposed technology will be an effective alternative desalination method in the future.展开更多
Photocatalysis as an emerging "green" energy conversion technology has attracted domestic and international attention.This technology uses semiconductor photocatalysts to convert solar energy into directly u...Photocatalysis as an emerging "green" energy conversion technology has attracted domestic and international attention.This technology uses semiconductor photocatalysts to convert solar energy into directly usable chemical energy,showing great potential for application in environmental pollutant purification and clean energy production,with broad development prospects.Among many semiconductor materials,tungsten trioxide(WO_(3)) is favored by researchers in the field of photocatalysis because of its good visible light response and excellent valence band hole oxidation properties.Currently,a large number of photocatalysts based on WO_(3),in particular W03-based composite photocatalysts,have been reported,and their applications cover a wide range of fields.In order to promote the development of WO_(3)-based photocatalysts and provide a reference for colleagues,we present a systematic summary of the applications and research progress of W03-based composites in the field of photocatalysis in recent years.Starting from the structural properties of WO_(3)itself,this article summarizes the preparation methods and structure-activity relationships of WO_(3)-based composite photocatalysts.Subsequently,it introduces the current application status of existing WO_(3)-based composite photocatalysts in CO_(2) reduction,hydrogen production,nitrogen fixation,and pollutant removal.Finally,the development prospects were analyzed.展开更多
To improve the mechanical properties of the electrospun nanofibrous membrane, the nonwoven fabrics and spacer fabrics were employed as support substrates to fabricate polyvinylidene fluoride(PVDF) nanofibrous composit...To improve the mechanical properties of the electrospun nanofibrous membrane, the nonwoven fabrics and spacer fabrics were employed as support substrates to fabricate polyvinylidene fluoride(PVDF) nanofibrous composite membranes. The influences of the substrate on membrane morphology, hydrophobicity, pore size and pore size distribution,porosity, mechanical strength and permeability were comprehensive evaluated. The electrospun composite membranes had a three dimension bead-fiber interconnected open structure and a rough membrane surface. The membrane surface presented a multilevel re-entrant structure and all the water contact angles were above 140°. In contrast with the pure PVDF nanofibrous membrane, the stress at break and the elastic modulus of the composite membranes increased by 4.5–16 times and 17.5–37 times, respectively. Since the spacer fabrics had less resistance to mass transfer, the membranes composited with spacer fabrics exhibited greater permeate fluxes compared with the composite membranes with the nonwoven fabrics as substrates.During the membrane distillation test, the highest permeate flux was up to 49.3 kg/m^2/hr at the feed temperature of 80°C. The long-time and repeat operation of membrane distillation desalination indicated the fabricated membrane with a good resistance to scaling and wetting.The results suggested the potential of the electrospun composite membrane for membrane distillation application.展开更多
In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagul...In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagulant at slightly acidic and neutral p H. Higher fluorescence quenching was produced for fulvic-like and humic-like fractions at p H 5. At p H 5, the humic-like fractions originating from the carboxylic acid, carboxyl and polysaccharide compounds were bound to aluminum first, followed by the fulvic-like fractions originating from the carboxyl and polysaccharide compounds. This finding also demonstrated that the activated functional groups of HA were involved in forming the Al-HA complex, which was accompanied by the removal of other groups by co-precipitation.Meanwhile, at p H 7, almost no fluorescence quenching occurred, and surface complexation was observed to occur, in which the activated functional groups were absorbed on the amorphous Al（OH）3. Two-dimensional FT-IR correlation spectroscopy indicated the sequence of HA structural change during coagulation with aluminum, with IR bands affected in the order of COOH〉 COO-〉NH deformation of amide Ⅱ〉 aliphatic hydroxyl C／OH at p H 5, and COO-〉aliphatic hydroxyl C／OH at p H 7. This study provides a promising pathway for analysis and insight into the priority of functional groups in the interaction between organic matters and metal coagulants.展开更多
A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coa...A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coal.The distribution laws of different sized particulate matter(PM)emission and the enrichment laws of elements in particles under diverse conditions(such as various excess air coefficients and different coal ratios)were systematically studied.The enrichments of PM under both non-staged and fuel-staged conditions were also investigated.The results indicated that fuel-staged combustion is more helpful in reducing PM emissions than non-staged combustion,and a suitable coal ratio is also beneficial for reducing PM emissions.The melted liquid steel slag drop captured the fly ash produced from pulverized combustion,thus reducing PM emission.The alkali metal elements(K,Na,and Mg),the trace elements(As and Ti).and S have an obvious enrichment tendency in PM]and PM2.5,A different coal ratio under fuel-staged combustion has a significant influence on the enrichment of Al,Si,Ca,and Fe in PM),whereas in PM2.5.PM4,and PM10,the effect of different coal ratios on the enrichment of each element is slight.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.31472312,41306152,31402283)the Qingdao Innovation Talents Program(No.13-CX-16)+2 种基金the National Key Technology Research and Development Program of China(No.2014BAD08B09)the Earmarked Fund for Modern Agroindustry Technology Research System(No.CARS-48)the Project for International S&T Cooperation Program of China(No.2014DFA31030)
文摘The present study sampled the intestinal content of healthy and unhealthy Atlantic salmon （Salmo salar L.）, the ambient water of unhealthy fish, and the biofilter material in the recirculating aquaculture system （RAS） to understand differences in the intestinal microbiota. The V4--V5 regions of the prokaryotic 16S rRNA genes in the samples were analyzed by MiSeq high-throughput sequencing. The fish were adults with no differences in body length or weight. Representative members of the intestinal microbiota were identified. The intestinal microbiota of the healthy fish included Proteobacteria （44.33%）, Actinobacteria （17.89%）, Baeteroidetes （15.25%）, and Firmicutes （9.11%）, among which the families Mierococcaceae and Oxalobacteraceae and genera Sphingomonas, Streptomyces, Pedobacter, Janthinobacterium, Burkholderia, and Balneimonas were most abundant. Proteobacteria （70.46%）, Bacteroidetes （7.59%）, and Firmicutes （7.55%） dominated the microbiota of unhealthy fish, and Chloroflexi （2.71%）, and Aliivibrio and Vibrio as well as genera in the family Aeromonadaceae were most strongly represented. Overall, the intestinal hindgut microbiota differed between healthy and unhealthy fish. This study offers a useful tool for monitoring the health status of fish and for screening the utility of probiotics by studying the intestinal microbiota.
基金supported by the National Natural Science Foundation of China[grant numbers 42275120 and 42075111]the National Key Research and Development Program[grant number 2023YFC3706101]。
文摘full understanding of the sources of atmospheric nitrous acid(HONO)in the polluted urban atmosphere re-mains a challenge.In this study,ambient HONO and relevant species were measured during January 2019 at an urban site in Beijing,China,and a budget analysis of HONO was conducted using a box model combined with field observations.Large nighttime“missing sources”of HONO were identified on heavily polluted days based on traditional sources,which had a significant correlation with the relative humidity,ammonia(NH_(3)),and aerosol surface area,and the promotional effect of NH_(3)for nitrogen dioxide(NO_(2))uptake on the wet aerosol surface was discussed.Then,an updated parameterization scheme for quantifying the enhanced heterogeneous reactions of NO_(2)on aerosol surfaces is proposed,and the missing nighttime sources of HONO could be substantially com-pensated after the new scheme was incorporated.Further evaluation on the contributions of HONO to hydroxyl radicals was conducted,and the authors found that the photolysis of HONO played a dominant role in the primary OH production on the polluted days(78%-90%).The study reveals great potential of an NH3-enhanced uptake coefficient of NO_(2)on the aerosol surface in the nocturnal HONO budget,and highlights the significance of HONO in the strong atmospheric oxidation capability during episodes with a heavily polluted atmosphere.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment (No.2017ZX07108-001-01)the Innovation Fund Project of Hebei University of Engineering (No.17129033041)the Science and Technology Research and Development Program of Handan (No.1723209054-2)
文摘Biofilms mediate crucial biochemical processes in aquatic ecosystems. It was hypothesized that eutrophication may promote the growth of biofilms, resulting in larger numbers of functional genes. However, the metabolic activity and the roles of biofilms in N cycling will be affected by ambient inorganic nitrogen availability, not by the abundance of functional genes. Biofilms were cultured either with replete inorganic nitrogen(N-rep) or without exogenous inorganic nitrogen supply(N-def) in a flow incubator, and the N-cycling gene abundances(nifH, N_2 fixation; amoA, ammonia oxidation, archaea and bacteria; nirS and nirK, denitrification) and enzyme activities(nitrogenase and nitrate reductase) were analyzed. The results showed that, comparing the N-def and N-rep biofilms, the former contained lower nifH gene abundance, but higher nitrogenase activity(NA), while the latter contained higher nifH gene abundance, but lower NA. Different patterns of NA diel variations corresponded to the dynamic microbial community composition and different stages of biofilm colonization. Ammonia oxidizing bacteria(AOB), detected only in N-def biofilms, were responsible for nitrification in biofilms. N-rep biofilms contained high nirS and nirK gene abundance and high denitrification enzyme activity, but N-def biofilms contained significantly lower denitrification gene abundance and activity. In general,the strong N_2 fixation in N-def biofilms and strong denitrification in N-rep biofilms assured the balance of aquatic ecosystems. The results suggested that evaluation of the functional processes of N cycling should not only focus on genetic potential, but also on the physiological activity of biofilms.
基金The National Basic Research Program (973) of China (No. 2004CB418506) the National Natural Science Foundation of China(No. 20377043 20337010)
文摘Biomarkers in higher plants played an important role to estimate exposure effects of pollutants in soil ecosystem and have received increasing attention in recent years. The qualitative and quantitative modifications arising in amplified fragment length polymorphism （AFLP） profiles as a measure of DNA effects were compared with a number of parameters, namely, the root length, total soluble protein content in root tips, chlorophylls content and shoot size to select the most sensitive biomarker responding to copper stress in the range of 0--600 mg/kg. The changes occurring in AFLP profiles of root tips following Cu treatment included loss of normal bands and appearance of new bands and variation in band intensity in comparison to that of the normal seedlings, A reduction in root length was observed at the 200 mg/kg of copper, which was accompanied with a decrease in total soluble protein content. According to their sensitivity to the copper toxicity, the above indicator rank in the following order： AFLP profiles 〉 total soluble protein content 〉 root length 〉 chlorophylls content 〉 shoot. We concluded that the AFLP offered a useful alternative hiomarker assay for the detection of genotoxic effects of environmental pollutants.
文摘A reverse osmosis （RO） desalination system coupled with tidal energy is proposed. The mechanical energy produced by the tidal energy through hydraulic turbine is directly used to drive the RO unit. The system performances and the water cost of the conventional and tidal energy RO systems are compared. It is found that the proposed tidal energy RO system can save water cost in the range of 31.0%-41.7% in comparison with the conventional RO system. There is an optimum feed pressure that leads to the lowest water cost. The tidal RO system can save more costs at a high feed pressure or a high water recovery rate. The optimum feed pressure of the tidal energy RO system is higher than that of the conventional RO system. The longer lifetime of the tidal energy RO system can save even more water cost. When the site development cost rate is lower than 40%, the water cost of the tidal energy RO system will be lower than that of the conventional RO system. The proposed technology will be an effective alternative desalination method in the future.
基金financially supported by the National Natural Science Foundation of China (No.22376051)the China Postdoctoral Science Foundation (Nos.2021T140512 and 2020M680869)the Natural Science Foundation of Hebei Province (No.B2021202001)。
文摘Photocatalysis as an emerging "green" energy conversion technology has attracted domestic and international attention.This technology uses semiconductor photocatalysts to convert solar energy into directly usable chemical energy,showing great potential for application in environmental pollutant purification and clean energy production,with broad development prospects.Among many semiconductor materials,tungsten trioxide(WO_(3)) is favored by researchers in the field of photocatalysis because of its good visible light response and excellent valence band hole oxidation properties.Currently,a large number of photocatalysts based on WO_(3),in particular W03-based composite photocatalysts,have been reported,and their applications cover a wide range of fields.In order to promote the development of WO_(3)-based photocatalysts and provide a reference for colleagues,we present a systematic summary of the applications and research progress of W03-based composites in the field of photocatalysis in recent years.Starting from the structural properties of WO_(3)itself,this article summarizes the preparation methods and structure-activity relationships of WO_(3)-based composite photocatalysts.Subsequently,it introduces the current application status of existing WO_(3)-based composite photocatalysts in CO_(2) reduction,hydrogen production,nitrogen fixation,and pollutant removal.Finally,the development prospects were analyzed.
基金supported by the National Key R&D Program of China (No.2016YFC0400500)the National Natural Science Foundation of China (Nos.51478454 and 51678555)
文摘To improve the mechanical properties of the electrospun nanofibrous membrane, the nonwoven fabrics and spacer fabrics were employed as support substrates to fabricate polyvinylidene fluoride(PVDF) nanofibrous composite membranes. The influences of the substrate on membrane morphology, hydrophobicity, pore size and pore size distribution,porosity, mechanical strength and permeability were comprehensive evaluated. The electrospun composite membranes had a three dimension bead-fiber interconnected open structure and a rough membrane surface. The membrane surface presented a multilevel re-entrant structure and all the water contact angles were above 140°. In contrast with the pure PVDF nanofibrous membrane, the stress at break and the elastic modulus of the composite membranes increased by 4.5–16 times and 17.5–37 times, respectively. Since the spacer fabrics had less resistance to mass transfer, the membranes composited with spacer fabrics exhibited greater permeate fluxes compared with the composite membranes with the nonwoven fabrics as substrates.During the membrane distillation test, the highest permeate flux was up to 49.3 kg/m^2/hr at the feed temperature of 80°C. The long-time and repeat operation of membrane distillation desalination indicated the fabricated membrane with a good resistance to scaling and wetting.The results suggested the potential of the electrospun composite membrane for membrane distillation application.
基金supported by the National Key Technology Support Program(No.2014BAC13B06)the National Natural Science Foundation of China(Nos.51378414,51178376)+1 种基金the Program for Innovative Research Team in Shaanxi(No.2013KCT-13)the Program for New Century Excellent Talents in the University of Ministry of Education of China(No.NCET-12-1043)
文摘In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagulant at slightly acidic and neutral p H. Higher fluorescence quenching was produced for fulvic-like and humic-like fractions at p H 5. At p H 5, the humic-like fractions originating from the carboxylic acid, carboxyl and polysaccharide compounds were bound to aluminum first, followed by the fulvic-like fractions originating from the carboxyl and polysaccharide compounds. This finding also demonstrated that the activated functional groups of HA were involved in forming the Al-HA complex, which was accompanied by the removal of other groups by co-precipitation.Meanwhile, at p H 7, almost no fluorescence quenching occurred, and surface complexation was observed to occur, in which the activated functional groups were absorbed on the amorphous Al（OH）3. Two-dimensional FT-IR correlation spectroscopy indicated the sequence of HA structural change during coagulation with aluminum, with IR bands affected in the order of COOH〉 COO-〉NH deformation of amide Ⅱ〉 aliphatic hydroxyl C／OH at p H 5, and COO-〉aliphatic hydroxyl C／OH at p H 7. This study provides a promising pathway for analysis and insight into the priority of functional groups in the interaction between organic matters and metal coagulants.
文摘A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coal.The distribution laws of different sized particulate matter(PM)emission and the enrichment laws of elements in particles under diverse conditions(such as various excess air coefficients and different coal ratios)were systematically studied.The enrichments of PM under both non-staged and fuel-staged conditions were also investigated.The results indicated that fuel-staged combustion is more helpful in reducing PM emissions than non-staged combustion,and a suitable coal ratio is also beneficial for reducing PM emissions.The melted liquid steel slag drop captured the fly ash produced from pulverized combustion,thus reducing PM emission.The alkali metal elements(K,Na,and Mg),the trace elements(As and Ti).and S have an obvious enrichment tendency in PM]and PM2.5,A different coal ratio under fuel-staged combustion has a significant influence on the enrichment of Al,Si,Ca,and Fe in PM),whereas in PM2.5.PM4,and PM10,the effect of different coal ratios on the enrichment of each element is slight.
