Conductive elastomers combining micromechanical sensitivity,lightweight adaptability,and environmental sustainability are critically needed for advanced flexible electronics requiring precise responsiveness and long-t...Conductive elastomers combining micromechanical sensitivity,lightweight adaptability,and environmental sustainability are critically needed for advanced flexible electronics requiring precise responsiveness and long-term wearability;however,the integration of these properties remains a significant challenge.Here,we present a biomass-derived conductive elastomer featuring a rationally engineered dynamic crosslinked network integrated with a tunable microporous architecture.This structural design imparts pronounced micromechanical sensitivity,an ultralow density(~0.25 g cm^(−3)),and superior mechanical compliance for adaptive deformation.Moreover,the unique micro-spring effect derived from the porous architecture ensures exceptional stretchability(>500%elongation at break)and superior resilience,delivering immediate and stable electrical response under both subtle(<1%)and large(>200%)mechanical stimuli.Intrinsic dynamic interactions endow the elastomer with efficient room temperature self-healing and complete recyclability without compromising performance.First-principles simulations clarify the mechanisms behind micropore formation and the resulting functionality.Beyond its facile and mild fabrication process,this work establishes a scalable route toward high-performance,sustainable conductive elastomers tailored for next-generation soft electronics.展开更多
As a key precursor of hydroxyl(OH) radicals, the budget of nitrous acid(HONO) at different altitudes has received extensive attention. In this study, vertically resolved observations of HONO, NO_(2), O_(3), and HCHO w...As a key precursor of hydroxyl(OH) radicals, the budget of nitrous acid(HONO) at different altitudes has received extensive attention. In this study, vertically resolved observations of HONO, NO_(2), O_(3), and HCHO were conducted during an autumn field campaign in Beijing in 2019. The significant correlation between HONO and NO2, along with variations in their ratios across different altitudes, underscores the importance of aerosol surface chemistry in HONO formation and its altitude-dependent behavior. To enhance the model performance, the heterogeneous conversion of NO_(2) and its photochemical enhancement are incorporated into the 1D model. The simulations reveal that the nocturnal HONO production is dominated by the heterogeneous conversion of NO_(2) both at the surface and aloft. During the daytime, groundsurface sources of HONO are mainly driven by nitrate photolysis and light-enhanced heterogeneous conversion of NO_(2).Meanwhile, a large portion of the HONO generated at the surface is transported upwards through vertical mixing. In the higher atmosphere, HONO originates from vertical transport and in situ processes. As precursors of OH radicals, the observed concentrations of HONO, O_(3), and HCHO exhibit distinct diurnal variations and vertical distribution patterns.HONO contributes to OH radical production predominantly during the early morning across all layers and it even becomes the main contributor throughout the daytime in the lowest layer near the ground, while O_(3) and HCHO become more prominent towards midday, especially in the higher layers. These results will be beneficial for a deeper understanding of the atmospheric oxidation process within the urban boundary layer.展开更多
In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate t...In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate the intermolecular stacking properties,profoundly impacting the film morphology and thus acting on the final power conversion efficiency(PCE) of the materials.In this study,two asymmetric acceptor molecules,Qx-Ph Br-BO and Qx-Ph Br-X,were synthesized by migrating the branching site of the outer side chain from the β-site to the γ-site.The branching site located at the γ-site could reduce the steric-hindrance effect and enhance the molecular aggregation behavior,giving rise to redshifted absorption and tight π-π stacking.Morphology analysis shows that the Qx-Ph Br-X-based devices have smoother surfaces and a phase-separated structure,which is more favorable for charge transport and extraction.The Qx-Ph Br-X-based devices exhibit balanced hole-electron mobility,efficient exciton dissociation,and low charge recombination.As a result,Qx-Ph Br-X with γ-site branching exhibits superior photovoltaic performance with a PCE of 17.16 %,which is significantly higher than that of Qx-Ph Br-BO at 16.28 %.These results highlight the importance of side-chain modifications for optimizing OSC efficiency and provide an important reference for precise tuning of side-chain structures in future molecular design.展开更多
Objective The study aim was to investigate the effects of exposure to multiple environmental organic pollutants on cardiopulmonary health with a focus on the potential mediating role of oxidative stress.Methods A repe...Objective The study aim was to investigate the effects of exposure to multiple environmental organic pollutants on cardiopulmonary health with a focus on the potential mediating role of oxidative stress.Methods A repeated-measures randomized crossover study involving healthy college students in Beijing was conducted. Biological samples, including morning urine and venous blood, were collected to measure concentrations of 29 typical organic pollutants, including hydroxy polycyclic aromatic hydrocarbons(OH-PAHs), bisphenol A and its substitutes, phthalates and their metabolites, parabens,and five biomarkers of oxidative stress. Health assessments included blood pressure measurements and lung function indicators.Results Urinary concentrations of 2-hydroxyphenanthrene(2-OH-PHE)(β = 4.35% [95% confidence interval(CI): 0.85%, 7.97%]), 3-hydroxyphenanthrene(β = 3.44% [95% CI: 0.19%, 6.79%]), and 4-hydroxyphenanthrene(4-OH-PHE)(β = 5.78% [95% CI: 1.27%, 10.5%]) were significantly and positively associated with systolic blood pressure. Exposures to 1-hydroxypyrene(1-OH-PYR)(β = 3.05% [95% CI:-4.66%,-1.41%]), 2-OH-PHE(β = 2.68% [95% CI:-4%,-1.34%]), and 4-OH-PHE(β = 3% [95% CI:-4.68%,-1.29%]) were negatively associated with the ratio of forced expiratory volume in the first second to forced vital capacity. These findings highlight the adverse effects of exposure to multiple pollutants on cardiopulmonary health. Biomarkers of oxidative stress, including 8-hydroxy-2'-deoxyguanosine and extracellular superoxide dismutase, mediated the effects of multiple OH-PAHs on blood pressure and lung function.Conclusion Exposure to multiple organic pollutants can adversely affect cardiopulmonary health.Oxidative stress is a key mediator of the effects of OH-PAHs on blood pressure and lung function.展开更多
Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewat...Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore, EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed. Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future.展开更多
Catalytic nickel was successfully incorporated into nanoscale iron to enhance its dechlorination efficiency for trichloroethylene （TCE）, one of the most commonly detected chlorinated organic compounds in groundwater...Catalytic nickel was successfully incorporated into nanoscale iron to enhance its dechlorination efficiency for trichloroethylene （TCE）, one of the most commonly detected chlorinated organic compounds in groundwater. Ethane was the predominant product. The greatest dechlorination efficiency was achieved at 22 molar percent of nickel. This nanoscale Ni-Fe is poorly ordered and inhomogeneous; iron dissolution occurred whereas nickel was relatively stable during the 24-hr reaction. The morphological characterization provided significant new insights on the mechanism of catalytic hydrodcchlorination by bimetallic nanoparticles. TCE degradation and ethane production rates were greatly affected by environmental parameters such as solution pH, temperature and common groundwater ions. Both rate constants decreased and then increased over the pH range of 6.5 to 8.0, with the minimum value occurring at pH 7.5. TCE degradation rate constant showed an increasing trend over the temperature range of 10 to 25℃. However, ethane production rate constant increased and then decreased over the range, with the maximum value occurring at 20℃, Most salts in the solution appeared to enhance the reaction in the first half hour but overall they displayed an inhibitory effect. Combined ions showed a similar effect as individual salts.展开更多
The environment of estuarine wetlands has been attracting worldwide attention. To study the spatial distribution of pollutants in the tidal flats of the Yangtze Estuary, Southeast China, the Eastern Tidal Flat of Chon...The environment of estuarine wetlands has been attracting worldwide attention. To study the spatial distribution of pollutants in the tidal flats of the Yangtze Estuary, Southeast China, the Eastern Tidal Flat of Chongming Island (EC) and the Jiuduansha Shoal (JS) of the estuary were selected as the study sites. At each of the two sites, a cross-transect from land to sea was established and topsoil and soil core samples in the cross-transect were collected spatially and seasonally to determine their contents of heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Mn, and Fe) and grain-size characteristics. The results showed that the heavy metal loads were commonly higher in the soils of nearshore high tidal flats and had a tendency of decreasing from land to sea at both of the study sites. The contents of heavy metals in the soils of the high and medial tidal flats were mostly higher in April and November but lower in July. Corresponding spatial and seasonal variations in grain size of the intertidal soils were also observed at the two study sites. The soils in the nearshore high tidal flats were finer and gradually got coarser seawards; they were relatively finer in April and November but coarser in July. Furthermore, the contents of heavy metals in the intertidal soils of both the sites EC and JS were significantly positively correlated with the clay (<2 μm) and 2-20 μm fractions, but negatively with the sand (>63 μm) and 20-63 μm fractions, which suggested that the heavy metals in the intertidal soils were primarily combined with the fine particulate fraction (<20 μm), especially clay, and hence the spatial and seasonal variations in heavy metals were actually caused by the change of the grain-size characteristics of the intertidal soils due to the different sedimentary environments in the estuary. The results of this study may also contribute to a better understanding of the soil formation and classification in the tidal flats of the Yangtze Estuary.展开更多
Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used ...Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd^(2+) and Pt^(0),respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.展开更多
Multi-axial differential optical absorption spectroscopy(MAX-DOAS)measurements were conducted in Xishuangbanna,Yunnan,China,between November 1,2021 and June 30,2022 to obtain vertical distributions of formaldehyde(HCH...Multi-axial differential optical absorption spectroscopy(MAX-DOAS)measurements were conducted in Xishuangbanna,Yunnan,China,between November 1,2021 and June 30,2022 to obtain vertical distributions of formaldehyde(HCHO)and glyoxal(CHOCHO).The observations show an increase in vertical column densities(VCDs)and volume mixing ratios(VMRs)for both HCHO and CHOCHO concentrations during periods of biomass combustion.The VCDs of HCHO and CHOCHO from TROPOMI are in good agreementwith the MAX-DOAS observations.(R^(2) HCHO=0.71;R^(2) CHOCHO=0.70).Regarding seasonal variations,HCHO predominantly occupies the upper layer(400-800 m)during the biomass burning,possibly attributed to the formation of secondary HCHO as the plume ascends during combustion.CHOCHO is primarily found in the lower layer(0-200 m),suggesting a longer lifespan for HCHO compared to CHOCHO,preventing the latter from diffusing to higher altitudes.Concerning the daily variation patterns,both HCHO and CHOCHO VMRs exhibited peaks at 9:00 and 13:00,which were attributed to the nighttime accumulation and midday oxidation.Furthermore,we also investigated the sources of volatile organic compounds(VOCs)using the CHOCHO to HCHO ratio(RGF).During the period of biomass burning,there are minimal differences in the daily RGF across layers,indicating that biomass burning is the predominant source.During the non-biomass burning period,the daily RGF shows significant differences among layers,indicating that emissions from biological and anthropogenic sources primarily contribute during the period.展开更多
Nano zero-valent iron(nZVI)is widely used in soil remediation due to its high reactivity.However,the easy agglomeration,poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its a...Nano zero-valent iron(nZVI)is widely used in soil remediation due to its high reactivity.However,the easy agglomeration,poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its application scale in Cr-contaminated soil remediation,especially in high concentration of Cr-contaminated soil.Herein,we found that the carboxymethyl cellulose on nZVI particles could increase the zeta potential value of soil and change the phase of nZVI.Along with the presence of biochar,97.0%and 96.6%Cr immobilization efficiency through CMC-nZVI/BC were respectively achieved in high and low concentrations of Cr-contaminated soils after 90-days remediation.In addition,the immobilization efficiency of Cr(VI)only decreased by 5.1%through CMC-nZVI/BC treatment after 10 weeks aging in air,attributing to the strong antioxidation ability.As for the surrounding Crcontaminated groundwater,the Cr(VI)removal capacity of CMC-nZVI/BC was evaluated under different reaction conditions through column experiments and COMSOL Multiphysics.CMC-nZVI/BC could efficiently remove 85%of Cr(VI)in about 400 hr when the initial Cr(VI)concentration was 40 mg/L and the flow rate was 0.5 mL/min.This study demonstrates that uniformly dispersed CMC-nZVI/BC has an excellent remediation effect on different concentrations of Cr-contaminated soils.展开更多
The metamorphic belt in central Jiangxi, located in the compound terrain within the Cathaysia, Yangtze Block and Caledonian fold zone of South China, is composed dominantly of meta-argillo-arenaceous rocks, with minor...The metamorphic belt in central Jiangxi, located in the compound terrain within the Cathaysia, Yangtze Block and Caledonian fold zone of South China, is composed dominantly of meta-argillo-arenaceous rocks, with minor amphibolite. These rocks underwent amphibolite-facies metamorphism. The meta-argillo-arenaceous rocks show large variations in major element composition, but have similar REE patterns and trace element composition, incompatible element and LIE enrichments [high Th/Sc ({0.57}-{3.59}), La/Sc ({1.46}-{12.4}), La/Yb ({5.84}-{19.0})] and variable Th/U ratios, with ΣREE=129-296μg/g, δEu={0.51}-{0.86}, and (La/Yb)-N={3.95}-{12.9}. The Nd isotopic model ages t-{DM} of these rocks vary from 1597 to 2124 Ma. Their {}+{143}Nd/+{144}Nd values are low [ε-{Nd}(0)={-11.4} to {-15.8}]. Some conclusions have been drawn as follows: (1) The metamorphic rocks in central Jiangxi Province are likely formed in a tectonic environment at the passive continental margin of the Cathaysia massif. (2) The metamorphosed argillo-arenaceous rocks are composed dominantly of upper crustal-source rocks (Al- and K|rich granitic or/and sedimentary rocks of Early Proterozoic), which experienced good sorting, slow deposition and more intense chemical weathering. (3) According to the whole-rock Sm-Nd isochron ages (1113±49 to 1199±26 Ma) of plagioclase-amphibole (schist) and Nd isotopic model age t-{DM} (1597-2124 Ma) of meta-argillo-arenaceous rocks, the metamorphic belt in central Jiangxi Province was formed during the Middle Proterozoic (1100-1600 Ma).展开更多
Summer and winter campaigns for the chemical compositions and sources of nonmethane hydrocarbons(NMHCs)and oxygenated volatile organic compounds(OVOCs)were conducted in Xi’an.Data from 57 photochemical assessment mon...Summer and winter campaigns for the chemical compositions and sources of nonmethane hydrocarbons(NMHCs)and oxygenated volatile organic compounds(OVOCs)were conducted in Xi’an.Data from 57 photochemical assessment monitoring stations for NMHCs and 20 OVOC species were analyzed.Significant seasonal differences were noted for total VOC(TVOC,NMHCs and OVOCs)concentrations and compositions.The campaign-average TVOC concentrations in winter(85.3±60.6 ppbv)were almost twice those in summer(47.2±31.6 ppbv).Alkanes and OVOCs were the most abundant category in winter and summer,respectively.NMHCs,but not OVOCs,had significantly higher levels on weekends than on weekdays.Total ozone formation potential was higher in summer than in winter(by 50%)because of the high concentrations of alkenes(particularly isoprene),high temperature,and high solar radiation levels in summer.The Hybrid Environmental Receptor Model(HERM)was used to conduct source apportionment for atmospheric TVOCs in winter and summer,with excellent accuracy.HERM demonstrated its suitability in a situation where only partial source profile data were available.The HERM results indicated significantly different seasonal source contributions to TVOCs in Xi’an.In particular,coal and biomass burning had contributions greater than half in winter(53.4%),whereas traffic sources were prevalent in summer(53.1%).This study’s results highlight the need for targeted and adjustable VOC control measures that account for seasonal differences in Xi’an;such measures should target not only the severe problem with VOC pollution but also the problem of consequent secondary pollution(e.g.,from ozone and secondary organic aerosols).展开更多
Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impac...Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impact on marine biodiversity and human health.This study examined the occurrence,spatial distribution,physical and chemical properties,ecological risks,and probable sources of MPs in estuarine and coastal marine environments in the northeastern Bay of Bengal.The average concentration of MPs in surface water of the Karnaphuli estuary,the Meghna estuary,and the southeastern coastal region were 916.7±462.6 items/m^(3),462.9±324.5 items/m^(3),and 350.0±190.5 items/m^(3),respectively,varying from 105.0±324.5 items/m^(3)to 1640.0±462.6 items/m^(3).In the sediments of the Karnaphuli estuary,the Meghna estuary,and the southeast coast of Bangladesh,the average amount of MPs were 94.3±33.1 items/kg,157.6±89.0 items/kg,and 134.3±38.7 items/kg,with a range of 60±33.1 items/kg to 334.3±89.0 items/kg.Most observed MPs were fibers(60.0%in the water;56.0%in the sediments),followed by fragments and lines.Detected MPs were dominated by polypropylene(20.7%)in the water,and acrylic(15.4%)in the sediment,black colored(76.2%in the water,72.7%in the sediments),and 200-500μm sized(48%in the water,37%in the sediments).Pollution Risk Index(PRI)indicated significant pollution levels(from medium to very high)in estuarine and coastal areas.Multi-statistical analysis indicated land-based inputs(tourists,local waste,agriculture,and industry)dominated the studied regions.The study emphasized the potential impact of MPs pollution on aquatic ecosystems,emphasizing the need for effective management,mitigation methods,continuous surveillance,and thorough evaluation.展开更多
Healthcare workers(HCWs)are at high risk of occupational exposure to the new pandemic human coronavirus,SARSCoV-2,and are a source of nosocomial transmission in airborne infectious isolation rooms(AIIRs).Here,we perfo...Healthcare workers(HCWs)are at high risk of occupational exposure to the new pandemic human coronavirus,SARSCoV-2,and are a source of nosocomial transmission in airborne infectious isolation rooms(AIIRs).Here,we performed comprehensive environmental contamination surveillance to evaluate the risk of viral transmission in AIIRs with 115 rooms in three buildings at the Shanghai Public Health Clinical Center,Shanghai,during the treatment of 334 patients infected with SARS-CoV-2.The results showed that the risk of airborne transmission of SARS-CoV-2 in AIIRs was low(1.62%,25/1544)due to the directional airflow and strong environmental hygiene procedures.However,we detected viral RNA on the surface of foot-operated openers and bathroom sinks in AIIRs(viral load:55.00–3154.50 copies/mL).This might be a source of contamination to connecting corridors and object surfaces through the footwear and gloves used by HCWs.The risk of infection was eliminated by the use of disposable footwear covers and the application of more effective environmental and personal hygiene measures.With the help of effective infection control procedures,none of 290 HCWs was infected when working in the AIIRs at this hospital.This study has provided information pertinent for infection control in AIIRs during the treatment of COVID-19 patients.展开更多
Modern logistics is a new industry during the construction of national economy. Based on analyzing the environmental problem that was led by the limitation of the strategy during enacting the program of the modern log...Modern logistics is a new industry during the construction of national economy. Based on analyzing the environmental problem that was led by the limitation of the strategy during enacting the program of the modern logistics, SEA for modern logistics was implemented. In this paper, procedure and indicator system in the SEA are constructed, and Environmental Check List to identify environmental impact factors of SEA for modern logistics is established. And a conception that indicates friendly degree of logistics system with resources and environment, degree of green, is introduced. With the example of modern logistics program of Dalian in China, two methods are applied, AHP and Fuzzy Comprehensive Evaluation Method, in the implement of SEA for modern logistics development. It is concluded that degree of green of modern logistics in Dalian is high. However, several important factors should be paid much attention to in the SEA for modern logistics as well as in the formulation and implement of modern logistics in Dalian.展开更多
This study focuses on the spatiotemporal distribution,urban-rural variations,and driving factors of ammonia Vertical Column Densities(VCDs)in China’s Yangtze River Delta region(YRD)from 2008 to 2020.Utilizing data fr...This study focuses on the spatiotemporal distribution,urban-rural variations,and driving factors of ammonia Vertical Column Densities(VCDs)in China’s Yangtze River Delta region(YRD)from 2008 to 2020.Utilizing data from the Infrared Atmospheric Sounding Interfer-ometer(IASI),Generalized Additive Models(GAM),and the GEOS-Chem chemical transport model,we observed a significant increase of NH_(3)VCDs in the YRD between 2014 and 2020.The spatial distribution analysis revealed higher NH_(3)concentrations in the northern part of the YRD region,primarily due to lower precipitation,alkaline soil,and intensive agricul-tural activities.NH_(3)VCDs in the YRD region increased significantly(65.18%)from 2008 to 2020.The highest growth rate occurs in the summer,with an annual average growth rate of 7.2%during the period from 2014 to 2020.Agricultural emissions dominated NH_(3)VCDs during spring and summer,with high concentrations primarily located in the agricultural areas adjacent to densely populated urban zones.Regions within several large urban areas have been discovered to exhibit relatively stable variations in NH_(3)VCDs.The rise in NH_(3)VCDs within the YRD region was primarily driven by the reduction of acidic gases like SO_(2),as emphasized by GAM modeling and sensitivity tests using the GEOS-Chem model.The concentration changes of acidic gases contribute to over 80%of the interannual variations in NH_(3)VCDs.This emphasizes the crucial role of environmental policies targeting the reduction of these acidic gases.Effective emission control is urgent tomitigate environmental hazards and secondary particulate matter,especially in the northern YRD.展开更多
Cyanobacteria can accumulate as a heavy biomass on the leeward side of large eutrophic lakes,posing a potential threat to public health.The mitigating capacity of three flocculants and their potential impacts on the m...Cyanobacteria can accumulate as a heavy biomass on the leeward side of large eutrophic lakes,posing a potential threat to public health.The mitigating capacity of three flocculants and their potential impacts on the major environmental features of water and sediments was evaluated.Results indicate that polyaluminum chloride(PAC)and ferric chloride(FeCl)are efficient flocculants that can rapidly mitigate cyanobacterial blooms with chlorophyll-a concentrations higher tnan 1500 ug/L within 15 min.In comparison,cationic starch with chitosan could only treat cyanobacterial blooms in chlorophyll-a concentrations of less than 200μg/L.The addition of FeClcaused a decline in the pH value,while dissolved oxygen in the water column dropped to 2 mg/L during cationic starch with chitosan treatment for a high cyanobacterial biomass group.Thus,a combination of flocculants and oxygenators should be considered when treating high-concentration cyanobacterial blooms for emergency purposes.Additionally,the cell lysis of cyanobacteria caused by cationic starch with chitosan can result in an increase in total dissolved phosphorus and total dissolved nitrogen.Furthermore,the high accumlation of nutrients in sediments after the settling of cyanobacteria can cause high internal phosphorus pollution.The increase in the total organic carbon of the sediments can threaten lake restoration achieved by planting submerged macrophytes.展开更多
This study investigated the variations in summer and winter PM_(2.5)concentrations and chemical composition in urban Xi'an before and during the COVID-19 pandemic restrictions.During the pandemic restrictions,summ...This study investigated the variations in summer and winter PM_(2.5)concentrations and chemical composition in urban Xi'an before and during the COVID-19 pandemic restrictions.During the pandemic restrictions,summer daytime PM_(2.5)concentrations remained comparable to pre-pandemic levels,while a reduction was noted at nighttime.Conversely,winter experienced a significant increase in both daytime and nighttime PM_(2.5)concentrations.Chemical composition analysis revealed reductions in secondary inorganic ion concentrations but notable increases in crustal matter concentrations during the pandemic restrictions,particularly evident in winter.The reductions in secondary inorganic ion concentrations were likely due to decreased emissions of corresponding anthropogenic precursors in summer,while linked to reductions in transformation efficiencies in winter.The heightened crustal matter concentrations were likely attributed to increased contributions of long-range air mass transport from dusty regions,especially prevalent in winter.Source apportionment using positive matrix factorization analysis provided quantitative insights into the distinct source profiles contributing to PM_(2.5)before and during the pandemic restrictions,with secondary inorganic-rich sources decreasing and dust-related sources increasing during the pandemic restrictions.Additionally,combustion sources,primarily from coal and biomass burning,showed higher contributions during winter.In conclusion,this study underscores the complex interplay between anthropogenic and natural factors influencing PM_(2.5)levels in Xi'an.Efforts to mitigate PM_(2.5)pollution should prioritize reducing anthropogenic emissions and implementing measures to control dust emissions,particularly when dust-related sources significantly contribute to elevated PM_(2.5)concentrations.These findings provide valuable insights into developing effective strategies for addressing the PM_(2.5)pollution problem in Xi'an.展开更多
How to achieve low energy consumption and high degradation efficiency(DRE)under mild conditions is an important issue in the field of sulfur hexafluoride(SF_(6))treatment.In this work,a new route of SF_(6)degradation ...How to achieve low energy consumption and high degradation efficiency(DRE)under mild conditions is an important issue in the field of sulfur hexafluoride(SF_(6))treatment.In this work,a new route of SF_(6)degradation promoted by Ni-doped ceria(NiO-CeO_(2))in a packed bed dielectric barrier discharge(PB-DBD)was proposed.The effects of Ni/Ce molar ratio,input power,SF_(6)concentration and flow rate on the DRE of SF_(6)were investigated.Compared with DBD or CeO_(2)-DBD alone,the combination of DBD and NiO-CeO_(2)can significantly promote the SF_(6)degradation at lower input power.The experimental results show that when the dosage of catalyst 1.5NiO-CeO_(2)(Ni/Ce mole ratio is 1.5%)is 5 g,DBD input power is 50 W and SF_(6)(1.5%SF_(6)/98.5%Ar)flow rate is 100 ml·min-1,the highest DRE can reach 97.7%and the energy yield can reach 11.5 g·(kW·h)-1.Adjusting the catalyst dosage according to the flux of SF_(6)(e.g.,using 10 g catalyst to degrade SF_(6)with a concentration of 1.5%and a flow rate of 80 ml·min-1),the DRE of nearly 99%can be achieved for a long time,which is crucial for industrial application.The mechanism deduction shows that the rich surface and mesopores of the catalyst are beneficial to the adsorption of SF_(6)and intermediates,while the doping of Ni can significantly increase the content of oxygen vacancies to improve the degradation.Meanwhile,when NiO-CeO_(2)is activated by DBD,the free O·can further promote the degradation.It is this coupling effect that leads to the high efficiency and low energy consumption of SF_(6)degradation under mild conditions.It can be expected that this coupling technology route will have a good application prospect in the field of SF_(6)treatment.展开更多
The North China Plain(NCP)frequently experiences ozone pollution events,which are generally related to cross-border transport at multiple scales.However,current methods of calculating ozone transport are insufficient ...The North China Plain(NCP)frequently experiences ozone pollution events,which are generally related to cross-border transport at multiple scales.However,current methods of calculating ozone transport are insufficient to account for ozone transport at different altitudes.To further understand the characteristics of ozone transport,we applied theWeather Research and Forecasting(WRF)model and the Comprehensive Air Quality Model with Extensions(CAMx)based on flux calculation method.The results showed that the simulated flux calculation method was suitable for revealing the evolutionary trend of ozone fluxes.Monthly inflows,outflows,and total net fluxes ranged from-32985.45 to 37361.46 t/d and indicated strong transport and significant spatial and temporal variations of ozone in the urban boundary segments.Vertical distribution analysis of the net ozone fluxes demonstrated that the net fluxes varied with the altitude,and the altitude at which the corresponding peaks were located had a strong correlation with the neighborhood and season.It was noteworthy that there were three main transport directions throughout the year,namely northwest-southeast(NW-SE),southeast-northwest(SE-NW),and southwestnortheast(SW-NE).Additionally,the ozone flux was mainly affected by temperature,wind speed,and ozone concentration,with the correlation coefficient varying by season and altitude,up to 0.78.Moreover,the correlation analysis of ozone flux and wind direction in each city further verified the accuracy of the transport direction.This paper can provide scientific and technological support for the study of ozone generation mechanisms and the solution of urban/interregional ozone pollution problems.展开更多
基金supported by National Natural Science Foundation of China(No.52103044)Double First-Class Initiative University of Science and Technology of China(KY2400000037)the Young Talent Programme(GG2400007009).
文摘Conductive elastomers combining micromechanical sensitivity,lightweight adaptability,and environmental sustainability are critically needed for advanced flexible electronics requiring precise responsiveness and long-term wearability;however,the integration of these properties remains a significant challenge.Here,we present a biomass-derived conductive elastomer featuring a rationally engineered dynamic crosslinked network integrated with a tunable microporous architecture.This structural design imparts pronounced micromechanical sensitivity,an ultralow density(~0.25 g cm^(−3)),and superior mechanical compliance for adaptive deformation.Moreover,the unique micro-spring effect derived from the porous architecture ensures exceptional stretchability(>500%elongation at break)and superior resilience,delivering immediate and stable electrical response under both subtle(<1%)and large(>200%)mechanical stimuli.Intrinsic dynamic interactions endow the elastomer with efficient room temperature self-healing and complete recyclability without compromising performance.First-principles simulations clarify the mechanisms behind micropore formation and the resulting functionality.Beyond its facile and mild fabrication process,this work establishes a scalable route toward high-performance,sustainable conductive elastomers tailored for next-generation soft electronics.
基金supported by the National Natural Science Foundation of China (Grant Nos.42075097,42177081 and 22176037)。
文摘As a key precursor of hydroxyl(OH) radicals, the budget of nitrous acid(HONO) at different altitudes has received extensive attention. In this study, vertically resolved observations of HONO, NO_(2), O_(3), and HCHO were conducted during an autumn field campaign in Beijing in 2019. The significant correlation between HONO and NO2, along with variations in their ratios across different altitudes, underscores the importance of aerosol surface chemistry in HONO formation and its altitude-dependent behavior. To enhance the model performance, the heterogeneous conversion of NO_(2) and its photochemical enhancement are incorporated into the 1D model. The simulations reveal that the nocturnal HONO production is dominated by the heterogeneous conversion of NO_(2) both at the surface and aloft. During the daytime, groundsurface sources of HONO are mainly driven by nitrate photolysis and light-enhanced heterogeneous conversion of NO_(2).Meanwhile, a large portion of the HONO generated at the surface is transported upwards through vertical mixing. In the higher atmosphere, HONO originates from vertical transport and in situ processes. As precursors of OH radicals, the observed concentrations of HONO, O_(3), and HCHO exhibit distinct diurnal variations and vertical distribution patterns.HONO contributes to OH radical production predominantly during the early morning across all layers and it even becomes the main contributor throughout the daytime in the lowest layer near the ground, while O_(3) and HCHO become more prominent towards midday, especially in the higher layers. These results will be beneficial for a deeper understanding of the atmospheric oxidation process within the urban boundary layer.
基金the financial support by the Beijing Natural Science Foundation (No.Z230018)the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB0520102)CAS Project for Young Scientists in Basic Research (No.YSBR-102)。
文摘In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate the intermolecular stacking properties,profoundly impacting the film morphology and thus acting on the final power conversion efficiency(PCE) of the materials.In this study,two asymmetric acceptor molecules,Qx-Ph Br-BO and Qx-Ph Br-X,were synthesized by migrating the branching site of the outer side chain from the β-site to the γ-site.The branching site located at the γ-site could reduce the steric-hindrance effect and enhance the molecular aggregation behavior,giving rise to redshifted absorption and tight π-π stacking.Morphology analysis shows that the Qx-Ph Br-X-based devices have smoother surfaces and a phase-separated structure,which is more favorable for charge transport and extraction.The Qx-Ph Br-X-based devices exhibit balanced hole-electron mobility,efficient exciton dissociation,and low charge recombination.As a result,Qx-Ph Br-X with γ-site branching exhibits superior photovoltaic performance with a PCE of 17.16 %,which is significantly higher than that of Qx-Ph Br-BO at 16.28 %.These results highlight the importance of side-chain modifications for optimizing OSC efficiency and provide an important reference for precise tuning of side-chain structures in future molecular design.
基金supported by the National Key Research&Development Program of the Ministry of Science and Technology of China(2022YFE0134900,2023YFC3708305,2023YFC3708302)Strategy Priority Research Program(Category B)of the Chinese Academy of Sciences(No.XDB0750300)National Natural Science Foundation of China(Grant No.42477455,42077390).
文摘Objective The study aim was to investigate the effects of exposure to multiple environmental organic pollutants on cardiopulmonary health with a focus on the potential mediating role of oxidative stress.Methods A repeated-measures randomized crossover study involving healthy college students in Beijing was conducted. Biological samples, including morning urine and venous blood, were collected to measure concentrations of 29 typical organic pollutants, including hydroxy polycyclic aromatic hydrocarbons(OH-PAHs), bisphenol A and its substitutes, phthalates and their metabolites, parabens,and five biomarkers of oxidative stress. Health assessments included blood pressure measurements and lung function indicators.Results Urinary concentrations of 2-hydroxyphenanthrene(2-OH-PHE)(β = 4.35% [95% confidence interval(CI): 0.85%, 7.97%]), 3-hydroxyphenanthrene(β = 3.44% [95% CI: 0.19%, 6.79%]), and 4-hydroxyphenanthrene(4-OH-PHE)(β = 5.78% [95% CI: 1.27%, 10.5%]) were significantly and positively associated with systolic blood pressure. Exposures to 1-hydroxypyrene(1-OH-PYR)(β = 3.05% [95% CI:-4.66%,-1.41%]), 2-OH-PHE(β = 2.68% [95% CI:-4%,-1.34%]), and 4-OH-PHE(β = 3% [95% CI:-4.68%,-1.29%]) were negatively associated with the ratio of forced expiratory volume in the first second to forced vital capacity. These findings highlight the adverse effects of exposure to multiple pollutants on cardiopulmonary health. Biomarkers of oxidative stress, including 8-hydroxy-2'-deoxyguanosine and extracellular superoxide dismutase, mediated the effects of multiple OH-PAHs on blood pressure and lung function.Conclusion Exposure to multiple organic pollutants can adversely affect cardiopulmonary health.Oxidative stress is a key mediator of the effects of OH-PAHs on blood pressure and lung function.
基金The National Natural Science Foundation of China (No. 50578053) and the Harbin Young Scientist Fund (No. 2003AFXXJ025)
文摘Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore, EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed. Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future.
基金supported by the National Natural Science Foundation of China(No.20807004)the General Research an Development Founding for Universities directly under the Ministry of Education of China(BUCTZZ1202)
文摘Catalytic nickel was successfully incorporated into nanoscale iron to enhance its dechlorination efficiency for trichloroethylene （TCE）, one of the most commonly detected chlorinated organic compounds in groundwater. Ethane was the predominant product. The greatest dechlorination efficiency was achieved at 22 molar percent of nickel. This nanoscale Ni-Fe is poorly ordered and inhomogeneous; iron dissolution occurred whereas nickel was relatively stable during the 24-hr reaction. The morphological characterization provided significant new insights on the mechanism of catalytic hydrodcchlorination by bimetallic nanoparticles. TCE degradation and ethane production rates were greatly affected by environmental parameters such as solution pH, temperature and common groundwater ions. Both rate constants decreased and then increased over the pH range of 6.5 to 8.0, with the minimum value occurring at pH 7.5. TCE degradation rate constant showed an increasing trend over the temperature range of 10 to 25℃. However, ethane production rate constant increased and then decreased over the range, with the maximum value occurring at 20℃, Most salts in the solution appeared to enhance the reaction in the first half hour but overall they displayed an inhibitory effect. Combined ions showed a similar effect as individual salts.
基金Supported by the National Natural Science Foundation of China (Nos. 41130526, 40971126, and 40771093)the Shanghai Leading Academic Discipline Project of China (No. S30109)
文摘The environment of estuarine wetlands has been attracting worldwide attention. To study the spatial distribution of pollutants in the tidal flats of the Yangtze Estuary, Southeast China, the Eastern Tidal Flat of Chongming Island (EC) and the Jiuduansha Shoal (JS) of the estuary were selected as the study sites. At each of the two sites, a cross-transect from land to sea was established and topsoil and soil core samples in the cross-transect were collected spatially and seasonally to determine their contents of heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Mn, and Fe) and grain-size characteristics. The results showed that the heavy metal loads were commonly higher in the soils of nearshore high tidal flats and had a tendency of decreasing from land to sea at both of the study sites. The contents of heavy metals in the soils of the high and medial tidal flats were mostly higher in April and November but lower in July. Corresponding spatial and seasonal variations in grain size of the intertidal soils were also observed at the two study sites. The soils in the nearshore high tidal flats were finer and gradually got coarser seawards; they were relatively finer in April and November but coarser in July. Furthermore, the contents of heavy metals in the intertidal soils of both the sites EC and JS were significantly positively correlated with the clay (<2 μm) and 2-20 μm fractions, but negatively with the sand (>63 μm) and 20-63 μm fractions, which suggested that the heavy metals in the intertidal soils were primarily combined with the fine particulate fraction (<20 μm), especially clay, and hence the spatial and seasonal variations in heavy metals were actually caused by the change of the grain-size characteristics of the intertidal soils due to the different sedimentary environments in the estuary. The results of this study may also contribute to a better understanding of the soil formation and classification in the tidal flats of the Yangtze Estuary.
基金supported by Zhongtian Iron and Steel-University of Science and Technology Beijing Youth Science and Technology Innovation Fund(No.FZTNTC2024050005)National Engineering Laboratory for Mobile Source Emission Control Technology,China(No.NELMS2020A07)The Fundamental Research Funds for the Central Universities,China(No.FRF-AT-20-12)。
文摘Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd^(2+) and Pt^(0),respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.
基金supported by Yunnan Fundamental Research Projects(No.202101AT070003)the National Natural Science Foundation of China(No.42365007).
文摘Multi-axial differential optical absorption spectroscopy(MAX-DOAS)measurements were conducted in Xishuangbanna,Yunnan,China,between November 1,2021 and June 30,2022 to obtain vertical distributions of formaldehyde(HCHO)and glyoxal(CHOCHO).The observations show an increase in vertical column densities(VCDs)and volume mixing ratios(VMRs)for both HCHO and CHOCHO concentrations during periods of biomass combustion.The VCDs of HCHO and CHOCHO from TROPOMI are in good agreementwith the MAX-DOAS observations.(R^(2) HCHO=0.71;R^(2) CHOCHO=0.70).Regarding seasonal variations,HCHO predominantly occupies the upper layer(400-800 m)during the biomass burning,possibly attributed to the formation of secondary HCHO as the plume ascends during combustion.CHOCHO is primarily found in the lower layer(0-200 m),suggesting a longer lifespan for HCHO compared to CHOCHO,preventing the latter from diffusing to higher altitudes.Concerning the daily variation patterns,both HCHO and CHOCHO VMRs exhibited peaks at 9:00 and 13:00,which were attributed to the nighttime accumulation and midday oxidation.Furthermore,we also investigated the sources of volatile organic compounds(VOCs)using the CHOCHO to HCHO ratio(RGF).During the period of biomass burning,there are minimal differences in the daily RGF across layers,indicating that biomass burning is the predominant source.During the non-biomass burning period,the daily RGF shows significant differences among layers,indicating that emissions from biological and anthropogenic sources primarily contribute during the period.
基金supported by the National Key Research and Development Program of China(No.2020YFC1808701)the Fundamental Research Funds for the Central Universities(No.buctrc202232).
文摘Nano zero-valent iron(nZVI)is widely used in soil remediation due to its high reactivity.However,the easy agglomeration,poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its application scale in Cr-contaminated soil remediation,especially in high concentration of Cr-contaminated soil.Herein,we found that the carboxymethyl cellulose on nZVI particles could increase the zeta potential value of soil and change the phase of nZVI.Along with the presence of biochar,97.0%and 96.6%Cr immobilization efficiency through CMC-nZVI/BC were respectively achieved in high and low concentrations of Cr-contaminated soils after 90-days remediation.In addition,the immobilization efficiency of Cr(VI)only decreased by 5.1%through CMC-nZVI/BC treatment after 10 weeks aging in air,attributing to the strong antioxidation ability.As for the surrounding Crcontaminated groundwater,the Cr(VI)removal capacity of CMC-nZVI/BC was evaluated under different reaction conditions through column experiments and COMSOL Multiphysics.CMC-nZVI/BC could efficiently remove 85%of Cr(VI)in about 400 hr when the initial Cr(VI)concentration was 40 mg/L and the flow rate was 0.5 mL/min.This study demonstrates that uniformly dispersed CMC-nZVI/BC has an excellent remediation effect on different concentrations of Cr-contaminated soils.
文摘The metamorphic belt in central Jiangxi, located in the compound terrain within the Cathaysia, Yangtze Block and Caledonian fold zone of South China, is composed dominantly of meta-argillo-arenaceous rocks, with minor amphibolite. These rocks underwent amphibolite-facies metamorphism. The meta-argillo-arenaceous rocks show large variations in major element composition, but have similar REE patterns and trace element composition, incompatible element and LIE enrichments [high Th/Sc ({0.57}-{3.59}), La/Sc ({1.46}-{12.4}), La/Yb ({5.84}-{19.0})] and variable Th/U ratios, with ΣREE=129-296μg/g, δEu={0.51}-{0.86}, and (La/Yb)-N={3.95}-{12.9}. The Nd isotopic model ages t-{DM} of these rocks vary from 1597 to 2124 Ma. Their {}+{143}Nd/+{144}Nd values are low [ε-{Nd}(0)={-11.4} to {-15.8}]. Some conclusions have been drawn as follows: (1) The metamorphic rocks in central Jiangxi Province are likely formed in a tectonic environment at the passive continental margin of the Cathaysia massif. (2) The metamorphosed argillo-arenaceous rocks are composed dominantly of upper crustal-source rocks (Al- and K|rich granitic or/and sedimentary rocks of Early Proterozoic), which experienced good sorting, slow deposition and more intense chemical weathering. (3) According to the whole-rock Sm-Nd isochron ages (1113±49 to 1199±26 Ma) of plagioclase-amphibole (schist) and Nd isotopic model age t-{DM} (1597-2124 Ma) of meta-argillo-arenaceous rocks, the metamorphic belt in central Jiangxi Province was formed during the Middle Proterozoic (1100-1600 Ma).
基金This research was supported by the Natural Science Foundation of China(Grant No.41907188)Natural Science Foundation of Shaanxi Province,China(Grant No.2019JQ-386)the China Postdoctoral Science Foundation(Grant No.2019M653658).
文摘Summer and winter campaigns for the chemical compositions and sources of nonmethane hydrocarbons(NMHCs)and oxygenated volatile organic compounds(OVOCs)were conducted in Xi’an.Data from 57 photochemical assessment monitoring stations for NMHCs and 20 OVOC species were analyzed.Significant seasonal differences were noted for total VOC(TVOC,NMHCs and OVOCs)concentrations and compositions.The campaign-average TVOC concentrations in winter(85.3±60.6 ppbv)were almost twice those in summer(47.2±31.6 ppbv).Alkanes and OVOCs were the most abundant category in winter and summer,respectively.NMHCs,but not OVOCs,had significantly higher levels on weekends than on weekdays.Total ozone formation potential was higher in summer than in winter(by 50%)because of the high concentrations of alkenes(particularly isoprene),high temperature,and high solar radiation levels in summer.The Hybrid Environmental Receptor Model(HERM)was used to conduct source apportionment for atmospheric TVOCs in winter and summer,with excellent accuracy.HERM demonstrated its suitability in a situation where only partial source profile data were available.The HERM results indicated significantly different seasonal source contributions to TVOCs in Xi’an.In particular,coal and biomass burning had contributions greater than half in winter(53.4%),whereas traffic sources were prevalent in summer(53.1%).This study’s results highlight the need for targeted and adjustable VOC control measures that account for seasonal differences in Xi’an;such measures should target not only the severe problem with VOC pollution but also the problem of consequent secondary pollution(e.g.,from ozone and secondary organic aerosols).
基金Supported by the National Natural Science Foundation of China(NSFC)Shared Voyage Project(Nos.41776088,41976018,42049911,U20A20103,U2005207)the Natural Science Key Foundation of Fujian Province,China(No.2020J01412103)+5 种基金the Hainan Province Science and Technology Special Fund(No.ZDYF2022SHFZ317)the Guangxi Talent and Innovation Base Project(No.2018AD19280)the Guangxi Funding Project(No.04024XM20N0006)the Beihai Science&Technology Project(Nos.201995037,202082031,202082022)the Natural Science Foundation of Xiamen City of China(No.502Z20227322)the China Scholarship Council(CSC Marine Scholarship)。
文摘Microplastics(MPs)have recently emerged as a significant environmental problem with devastating consequences for organisms.Understanding MPs pollution in the Bay of Bengal is crucial for assessing its ecological impact on marine biodiversity and human health.This study examined the occurrence,spatial distribution,physical and chemical properties,ecological risks,and probable sources of MPs in estuarine and coastal marine environments in the northeastern Bay of Bengal.The average concentration of MPs in surface water of the Karnaphuli estuary,the Meghna estuary,and the southeastern coastal region were 916.7±462.6 items/m^(3),462.9±324.5 items/m^(3),and 350.0±190.5 items/m^(3),respectively,varying from 105.0±324.5 items/m^(3)to 1640.0±462.6 items/m^(3).In the sediments of the Karnaphuli estuary,the Meghna estuary,and the southeast coast of Bangladesh,the average amount of MPs were 94.3±33.1 items/kg,157.6±89.0 items/kg,and 134.3±38.7 items/kg,with a range of 60±33.1 items/kg to 334.3±89.0 items/kg.Most observed MPs were fibers(60.0%in the water;56.0%in the sediments),followed by fragments and lines.Detected MPs were dominated by polypropylene(20.7%)in the water,and acrylic(15.4%)in the sediment,black colored(76.2%in the water,72.7%in the sediments),and 200-500μm sized(48%in the water,37%in the sediments).Pollution Risk Index(PRI)indicated significant pollution levels(from medium to very high)in estuarine and coastal areas.Multi-statistical analysis indicated land-based inputs(tourists,local waste,agriculture,and industry)dominated the studied regions.The study emphasized the potential impact of MPs pollution on aquatic ecosystems,emphasizing the need for effective management,mitigation methods,continuous surveillance,and thorough evaluation.
基金supported by the Special National Project on investigation of basic resources of China(Grant 2019FY101500)the National Natural Science Foundation of China(Grants 81861138003 and 31930001)supported an Australian Research Council(ARC)Australian Laureate Fellowship(FL170100022)。
文摘Healthcare workers(HCWs)are at high risk of occupational exposure to the new pandemic human coronavirus,SARSCoV-2,and are a source of nosocomial transmission in airborne infectious isolation rooms(AIIRs).Here,we performed comprehensive environmental contamination surveillance to evaluate the risk of viral transmission in AIIRs with 115 rooms in three buildings at the Shanghai Public Health Clinical Center,Shanghai,during the treatment of 334 patients infected with SARS-CoV-2.The results showed that the risk of airborne transmission of SARS-CoV-2 in AIIRs was low(1.62%,25/1544)due to the directional airflow and strong environmental hygiene procedures.However,we detected viral RNA on the surface of foot-operated openers and bathroom sinks in AIIRs(viral load:55.00–3154.50 copies/mL).This might be a source of contamination to connecting corridors and object surfaces through the footwear and gloves used by HCWs.The risk of infection was eliminated by the use of disposable footwear covers and the application of more effective environmental and personal hygiene measures.With the help of effective infection control procedures,none of 290 HCWs was infected when working in the AIIRs at this hospital.This study has provided information pertinent for infection control in AIIRs during the treatment of COVID-19 patients.
基金Under the auspices of the key project of Shandong Provincial EnvironmentalProtectionBureau (No .2003447)
文摘Modern logistics is a new industry during the construction of national economy. Based on analyzing the environmental problem that was led by the limitation of the strategy during enacting the program of the modern logistics, SEA for modern logistics was implemented. In this paper, procedure and indicator system in the SEA are constructed, and Environmental Check List to identify environmental impact factors of SEA for modern logistics is established. And a conception that indicates friendly degree of logistics system with resources and environment, degree of green, is introduced. With the example of modern logistics program of Dalian in China, two methods are applied, AHP and Fuzzy Comprehensive Evaluation Method, in the implement of SEA for modern logistics development. It is concluded that degree of green of modern logistics in Dalian is high. However, several important factors should be paid much attention to in the SEA for modern logistics as well as in the formulation and implement of modern logistics in Dalian.
基金supported by the Joint Funds of the National Natural Science Foundation of China(No.U21A2027)the New Cornerstone Science Foundation through the XPLORER PRIZE(2023-1033).
文摘This study focuses on the spatiotemporal distribution,urban-rural variations,and driving factors of ammonia Vertical Column Densities(VCDs)in China’s Yangtze River Delta region(YRD)from 2008 to 2020.Utilizing data from the Infrared Atmospheric Sounding Interfer-ometer(IASI),Generalized Additive Models(GAM),and the GEOS-Chem chemical transport model,we observed a significant increase of NH_(3)VCDs in the YRD between 2014 and 2020.The spatial distribution analysis revealed higher NH_(3)concentrations in the northern part of the YRD region,primarily due to lower precipitation,alkaline soil,and intensive agricul-tural activities.NH_(3)VCDs in the YRD region increased significantly(65.18%)from 2008 to 2020.The highest growth rate occurs in the summer,with an annual average growth rate of 7.2%during the period from 2014 to 2020.Agricultural emissions dominated NH_(3)VCDs during spring and summer,with high concentrations primarily located in the agricultural areas adjacent to densely populated urban zones.Regions within several large urban areas have been discovered to exhibit relatively stable variations in NH_(3)VCDs.The rise in NH_(3)VCDs within the YRD region was primarily driven by the reduction of acidic gases like SO_(2),as emphasized by GAM modeling and sensitivity tests using the GEOS-Chem model.The concentration changes of acidic gases contribute to over 80%of the interannual variations in NH_(3)VCDs.This emphasizes the crucial role of environmental policies targeting the reduction of these acidic gases.Effective emission control is urgent tomitigate environmental hazards and secondary particulate matter,especially in the northern YRD.
基金Supported by the National Science Foundation of China(Nos.32071573,41877544)the Science and Technology Service Network Initiative of Chinese Academy of Sciences(No.KFJ-STS-QYZD-2021-01-002)the Science and Technology Achievement Transformation Foundation of Inner Mongolia Autonomous Region(No.2021CG0013)。
文摘Cyanobacteria can accumulate as a heavy biomass on the leeward side of large eutrophic lakes,posing a potential threat to public health.The mitigating capacity of three flocculants and their potential impacts on the major environmental features of water and sediments was evaluated.Results indicate that polyaluminum chloride(PAC)and ferric chloride(FeCl)are efficient flocculants that can rapidly mitigate cyanobacterial blooms with chlorophyll-a concentrations higher tnan 1500 ug/L within 15 min.In comparison,cationic starch with chitosan could only treat cyanobacterial blooms in chlorophyll-a concentrations of less than 200μg/L.The addition of FeClcaused a decline in the pH value,while dissolved oxygen in the water column dropped to 2 mg/L during cationic starch with chitosan treatment for a high cyanobacterial biomass group.Thus,a combination of flocculants and oxygenators should be considered when treating high-concentration cyanobacterial blooms for emergency purposes.Additionally,the cell lysis of cyanobacteria caused by cationic starch with chitosan can result in an increase in total dissolved phosphorus and total dissolved nitrogen.Furthermore,the high accumlation of nutrients in sediments after the settling of cyanobacteria can cause high internal phosphorus pollution.The increase in the total organic carbon of the sediments can threaten lake restoration achieved by planting submerged macrophytes.
基金supported by the Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0141)the Qinchuanyuan introducing high-level innovation and entrepreneurship talent program(No.QCYRCXM-2022-363)the“Young Talent Support Plan”of Xi'an Jiaotong University(No.ND6J027).
文摘This study investigated the variations in summer and winter PM_(2.5)concentrations and chemical composition in urban Xi'an before and during the COVID-19 pandemic restrictions.During the pandemic restrictions,summer daytime PM_(2.5)concentrations remained comparable to pre-pandemic levels,while a reduction was noted at nighttime.Conversely,winter experienced a significant increase in both daytime and nighttime PM_(2.5)concentrations.Chemical composition analysis revealed reductions in secondary inorganic ion concentrations but notable increases in crustal matter concentrations during the pandemic restrictions,particularly evident in winter.The reductions in secondary inorganic ion concentrations were likely due to decreased emissions of corresponding anthropogenic precursors in summer,while linked to reductions in transformation efficiencies in winter.The heightened crustal matter concentrations were likely attributed to increased contributions of long-range air mass transport from dusty regions,especially prevalent in winter.Source apportionment using positive matrix factorization analysis provided quantitative insights into the distinct source profiles contributing to PM_(2.5)before and during the pandemic restrictions,with secondary inorganic-rich sources decreasing and dust-related sources increasing during the pandemic restrictions.Additionally,combustion sources,primarily from coal and biomass burning,showed higher contributions during winter.In conclusion,this study underscores the complex interplay between anthropogenic and natural factors influencing PM_(2.5)levels in Xi'an.Efforts to mitigate PM_(2.5)pollution should prioritize reducing anthropogenic emissions and implementing measures to control dust emissions,particularly when dust-related sources significantly contribute to elevated PM_(2.5)concentrations.These findings provide valuable insights into developing effective strategies for addressing the PM_(2.5)pollution problem in Xi'an.
基金financial support from the National Natural Science Foundation of China(U23A20105).
文摘How to achieve low energy consumption and high degradation efficiency(DRE)under mild conditions is an important issue in the field of sulfur hexafluoride(SF_(6))treatment.In this work,a new route of SF_(6)degradation promoted by Ni-doped ceria(NiO-CeO_(2))in a packed bed dielectric barrier discharge(PB-DBD)was proposed.The effects of Ni/Ce molar ratio,input power,SF_(6)concentration and flow rate on the DRE of SF_(6)were investigated.Compared with DBD or CeO_(2)-DBD alone,the combination of DBD and NiO-CeO_(2)can significantly promote the SF_(6)degradation at lower input power.The experimental results show that when the dosage of catalyst 1.5NiO-CeO_(2)(Ni/Ce mole ratio is 1.5%)is 5 g,DBD input power is 50 W and SF_(6)(1.5%SF_(6)/98.5%Ar)flow rate is 100 ml·min-1,the highest DRE can reach 97.7%and the energy yield can reach 11.5 g·(kW·h)-1.Adjusting the catalyst dosage according to the flux of SF_(6)(e.g.,using 10 g catalyst to degrade SF_(6)with a concentration of 1.5%and a flow rate of 80 ml·min-1),the DRE of nearly 99%can be achieved for a long time,which is crucial for industrial application.The mechanism deduction shows that the rich surface and mesopores of the catalyst are beneficial to the adsorption of SF_(6)and intermediates,while the doping of Ni can significantly increase the content of oxygen vacancies to improve the degradation.Meanwhile,when NiO-CeO_(2)is activated by DBD,the free O·can further promote the degradation.It is this coupling effect that leads to the high efficiency and low energy consumption of SF_(6)degradation under mild conditions.It can be expected that this coupling technology route will have a good application prospect in the field of SF_(6)treatment.
基金supported by the National Natural Science Foundation of China(No.52200120)the R&D Program of Beijing Municipal Education Commission(No.KM202310011003)。
文摘The North China Plain(NCP)frequently experiences ozone pollution events,which are generally related to cross-border transport at multiple scales.However,current methods of calculating ozone transport are insufficient to account for ozone transport at different altitudes.To further understand the characteristics of ozone transport,we applied theWeather Research and Forecasting(WRF)model and the Comprehensive Air Quality Model with Extensions(CAMx)based on flux calculation method.The results showed that the simulated flux calculation method was suitable for revealing the evolutionary trend of ozone fluxes.Monthly inflows,outflows,and total net fluxes ranged from-32985.45 to 37361.46 t/d and indicated strong transport and significant spatial and temporal variations of ozone in the urban boundary segments.Vertical distribution analysis of the net ozone fluxes demonstrated that the net fluxes varied with the altitude,and the altitude at which the corresponding peaks were located had a strong correlation with the neighborhood and season.It was noteworthy that there were three main transport directions throughout the year,namely northwest-southeast(NW-SE),southeast-northwest(SE-NW),and southwestnortheast(SW-NE).Additionally,the ozone flux was mainly affected by temperature,wind speed,and ozone concentration,with the correlation coefficient varying by season and altitude,up to 0.78.Moreover,the correlation analysis of ozone flux and wind direction in each city further verified the accuracy of the transport direction.This paper can provide scientific and technological support for the study of ozone generation mechanisms and the solution of urban/interregional ozone pollution problems.
