Polycyclic Aromatic Hydrocarbons(PAHs),along with their derivatives nitro-PAHs and oxy-PAHs,are globally recognized toxic pollutants.This research conducted daily PM_(2.5)sampling in winter 2021 at three urban(YNCE,SW...Polycyclic Aromatic Hydrocarbons(PAHs),along with their derivatives nitro-PAHs and oxy-PAHs,are globally recognized toxic pollutants.This research conducted daily PM_(2.5)sampling in winter 2021 at three urban(YNCE,SWP,and NG)and three suburban sites(HC,CTV,and YNE)in the Ili River Valley(IRV).For the first time in the IRV,a comprehensive study on 39 PAHs and derivatives was carried out.The results showed that the average∑_(16)PAHs concentration was 130.21±98.94 ng/m^(3),with 16PAHs constituting the dominant fraction(112.51±86.48 ng/m^(3)).The mean BaP and the total BaP equivalent quotient(TEQ)concentrations were 10.28±8.85 ng/m^(3)and 19.74±16.70 ng/m^(3),respectively.Approximately 88%of the daily BaP averages and 98%of the daily TEQ averages exceeded the national daily average standard of BaP(2.5 ng/m^(3)),indicating severe local BaP pollution.Urban sites had notably higher∑PAHs and TEQ concentrations than suburban sites,attributed to increased vehicular traffic and coal combustion in urban areas.PMF results showed that traffic emissions(32.7%-60.5%),coal combustion(13.9%-24.3%)and secondary formation(14.7%-22.7%)were the primary contributors to∑PAHs.Urban sites experienced a greater influence from traffic,while suburban sites were more impacted by coal and biomass burning.On polluted days,traffic sources’contributions increased significantly at HC,YNE,NG and YNCE sites,and secondary formation sources’contributions grew at CTV and YNCE sites.The sourcedependent BaPeq results underscored the role of secondary-formed PAH derivatives in TEQ.展开更多
Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recen...Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recent years.In this study,the occurrence,distribution,source,and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry,normal,and flood seasons of 2018.The PAH concentrations ranged from 255 to 7298 ng/L and the NPAH concentrations ranged from not-detected(ND)to 212 ng/L.Among the target analytes,2-nitrofluorene(2-n Flu)was the predominant NPAH,with a detection frequency ranging from 85%to 90%and a maximum concentration of 56.2 ng/L.The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds.In terms of seasonal variation,the highest levels of the NPAHs and PAHs were in the dry season and flood season,respectively.Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion,whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion.The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model.The carcinogenic risk level of the targets ranged from 2.09×10^(-7)to 5.75×10^(-5)and some surface water samples posed a potential health risk.展开更多
Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,...Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,formation mechanism,and health risk assessment of them in heating season,particulate matter(PM)were collected in Beijing urban area from December 26,2017 to January 17,2018.PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS).Average daily concentrations of PAHs and NPAHs were(78±54)ng/m^(3)and(783±684)pg/m^(3),respectively.The concentrations of them were significantly higher at nighttime than at daytime,and NPAHs concentrations were 1-2 orders of magnitude lower than PAHs concentrations.In the heating season,the dominant species of PAHs include benzo[b]fluoranthene,fluoranthene,pyrene,and chrysene,while 9-nitroanthracene,2+3-nitrofluoranthene,and 2-nitropyrene were dominant species for NPAHs.NPAHs were found to have a single peak during heating and to be primarily distributed in the 0.4-0.7μm particle size.Primary emissions such as biomass burning,coal combustion,and traffic emissions were the major sources of PAHs.NPAHs were produced by the primary source of vehicle emissions and the secondary reaction triggered by OH radicals,as well as biomass burning during daytime.According to the health risk assessment,the total carcinogenic risk was higher in adults than in children.While upon oral ingestion,the carcinogenic risk in children was higher than that of adults,but the risk of adults was higher than children through skin contact and respiratory inhalation.展开更多
Intensive daytime and nighttime sampling was carried out from 23 Oct to 31 Dec 2008 to investigate the occurrence of nitrated polycyclic aromatic hydrocarbons （NPAHs） in PM1o at a roadside site in Xiamen, China. At ...Intensive daytime and nighttime sampling was carried out from 23 Oct to 31 Dec 2008 to investigate the occurrence of nitrated polycyclic aromatic hydrocarbons （NPAHs） in PM1o at a roadside site in Xiamen, China. At the same time, six PMt0 samples were collected from a nearby roadway tunnel for comparison. Six NPAHs, namely 9-nitroanthracene, 2- and 3-nitrofluoranthene, 1- nitropyrene, 7-nitrobenz[a]anthracene, and 6-nitrobenzo[a]pyrene, were identified and quantified using GC/MS in negative ion chemical ionization mode. The average total concentration of six NPAHs （~NPAHs） in the cold season （26 Nov-31 Dec） was 2.3 （daytime） and 9.9 （nighttime） times higher than those in the warm season. Significant statistical difference （p 〈 0.01, 2-tailed） of ∑NPAHs between daytime and nighttime was found during both the warm and cold seasons. NPAHs were significantly positively correlated with their parent PAHs and nitrogen dioxide but negatively correlated with ambient temperature. The ratio of 2 ＋ 3-nitrofluoranthene to 1- nitropyrene exhibited a similar diurnal pattern as ZNPAHs and was generally greater than 5, indicating the importance of secondary atmospheric formation. The diurnal variations of NPAHs were all influenced by the diurnal variations of PAHs, nitrogen dioxide, sunlight, and temperature. The daily inhalable exposure to the six NPAHs in the tunnel was much higher than the roadside values in the warm season but only slightly higher than those in the cold season.展开更多
Air pollutants can potentially lead to nitration of allergic proteins,thus promoting sensitization of these allergens.However,little is currently known about the nitration status of house dust mite(HDM)allergens.We id...Air pollutants can potentially lead to nitration of allergic proteins,thus promoting sensitization of these allergens.However,little is currently known about the nitration status of house dust mite(HDM)allergens.We identified the occurrence of nitrated products of two major HDM allergens Der f 1 and Der p 1 in dust samples collected from college dormitories in eastern China and assessed their associated health risk.The results showed that both non-nitrated and nitrated forms of the two allergens were detected in the dust in the range of non-detected(ND)-10.6,1.44-15.4,ND-22.4,ND-7.28μg/g for non-nitrated Der f 1,nitrated Der f 1,non-nitrated Der p 1 and nitrated Der p 1,respectively.The median rates of nitration were determined as 74.0%for Der f 1 and 20.4% for Der p 1 at consideration of one nitration site.Further analysis reveals that the levels of HDM allergens and their nitrated products were found to be generally higher during winter,in dormitories of lower altitude and with female occupants.Furthermore,the calculated risk indexes were at considerably high levels.Our findings suggest that nitrated HDM allergens have already accumulated in the environment at such significant levels and their associated health risk calls for our immediate attention.展开更多
The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has...The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has been employed as a coating agent.The SEM micrographs revealed distinct features of both pure AN and NC,contrasting with the irregular granular surface topography of the coated AN particles,demonstrating the adherence of NC on the AN surface.Structural analysis via infrared spectroscopy(IR)demonstrated a successful association of AN and NC,with slight shifts observed in IR bands indicating interfacial interactions.Powder X-ray Diffraction(PXRD)analysis further elucidated the structural changes induced by the coating process,revealing that the NC coating altered the crystallization pattern of its pure form.Thermal analysis demonstrates distinct profiles for pure and coated AN,for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6℃,and 36%,respectively.Furthermore,the presence of NC coating alters the intermolecular forces within the composite system,leading to a reduction in melting enthalpy of coated AN by~39%compared to pure AN.The thermal decomposition analysis shows a two-step thermolysis process for coated AN,with a significant increase in the released heat by about 78%accompanied by an increase in the activation barrier of NC and AN thermolysis,demonstrating a stabilized reactivity of the AN-NC particles.These findings highlight the synergistic effect of NC coating on AN particles,which contributed to a structural and reactive stabilization of both AN and NC,proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations.展开更多
Nitrate contamination of groundwater is a worldwide problem, particularly in agricultural countries. Exposure to high levels of nitrates in groundwater can have adverse effects on the health of residents who use groun...Nitrate contamination of groundwater is a worldwide problem, particularly in agricultural countries. Exposure to high levels of nitrates in groundwater can have adverse effects on the health of residents who use groundwater for drinking. This study aims to assess the health risk associated with the ingestion of nitrates in well water in the town of M’bahiakro. Health risk maps were created on the basis of hazard quotients (HQ) using the US Environmental Protection Agency (USEPA) health risk assessment model. The results indicate that residents of the Koko, Dougouba and Baoulekro neighbourhoods, whatever their age, are potentially exposed to the toxic effects of NO3−during their daily intake of nitrate-contaminated well water, with reference to hazard quotients (HQ) greater than 1. Nitrate concentrations in the groundwater should therefore be controlled in order to prevent their harmful effects on the health of the population and guarantee its use in rice-growing activities in M’Bahiakro.展开更多
Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution issues.We report a CuO nanoparticles in...Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution issues.We report a CuO nanoparticles incorporated on nitrogen-doped porous carbon (CuO@NC) catalyst for NO_(3)-RR.Part of Cu(Ⅱ) is reduced to Cu(Ⅰ) during the NO_(3)-RR process to construct Cu(Ⅰ)-Cu(Ⅱ) pairs,confirmed by in situ X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.Density functional theory (DFT) calculations indicated that the formation of Cu(Ⅰ) could provide a reaction path with smaller energy barrier for NO_(3)-RR,while Cu(Ⅱ) effectively suppressed the competition of hydrogen evolution reaction (HER).As a result,CuO@NC catalyst achieved a Faradaic efficiency of 84.2% at -0.49 V versus reversible hydrogen electrode (RHE),and a NH_(3)yield rate of 17.2 mg h^(-1)mg^(-1)cat.at -0.79 V vs.RHE,higher than the HaberBosch process (<3.4 g h^(-1)g^(-1)cat.).This work may open a new avenue for effective NO_(3)-RR by modulating oxidation states.展开更多
Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategi...Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategies.A high-resolution PM_(2.5) chemical composition dataset(CAQRA-aerosol)is developed in this study,which provides hourly maps of organic carbon,black carbon,ammonium,nitrate,and sulfate in China from 2013 to 2020 with a horizontal resolution of 15 km.This paper describes the method,access,and validation results of this dataset.It shows that CAQRA-aerosol has good consistency with observations and achieves higher or comparable accuracy with previous PM_(2.5) composition datasets.Based on CAQRA-aerosol,spatiotemporal changes of different PM_(2.5) compositions were investigated from a national viewpoint,which emphasizes different changes of nitrate from other compositions.The estimated annual rate of population-weighted concentrations of nitrate is 0.23μg m^(−3)yr^(−1) from 2015 to 2020,compared with−0.19 to−1.1μg m^(−3)yr^(−1) for other compositions.The whole dataset is freely available from the China Air Pollution Data Center(https://doi.org/10.12423/capdb_PKU.2023.DA).展开更多
Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N...Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.展开更多
The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation ...The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation and oxygen evolution competition,sluggish kinetics,low Faradaic efficiency,and limited nitrate yields.In this work,a novel two-dimensional(2D)layered MOF Mn-BCPPy(H_(2)BCPPy=3,5-di(4'-carboxyphenyl)pyridine)has been successfully synthesized.The framework is composed of a rod-manganese motifs and possesses abundant active sites including open metal sites(OMSs)and Lewis base sites(LBSs).The Mn-BCPPy is the first MOF catalyst applied in electrocatalytic NOR which NO_(3)^(-)exhibited relatively high activity with a yield of 99.75μg/(h·mg)and a Faraday efficiency(FE)of 32.09%.Furthermore,it can be used as fluorescent sensor for selectively and sensitively detect nitrofuran antibiotics(NFs).Therefore,this work explores the application of MOF materials in the field of electrocatalytic NOR,which reveals that manganese-based MOFs have great potential prospects.展开更多
A static corrosion experiment of 347H stainless steel alloyed with elements Cu and Mo was carried out in a nitrate molten salt(60%NaNO_(3)+40%KNO_(3))at 565℃ for 720 h.The effects of elements Cu and Mo on the corrosi...A static corrosion experiment of 347H stainless steel alloyed with elements Cu and Mo was carried out in a nitrate molten salt(60%NaNO_(3)+40%KNO_(3))at 565℃ for 720 h.The effects of elements Cu and Mo on the corrosion resistance of 347H stainless steel in molten salt were investigated by analyzing the phase composition,microstructure and chemical composition of the corrosion products.The results show that the grain refinement induced by element Mo imparts the stainless steel with optimal corrosion resistance at a medium grain size.Furthermore,the formation of MoC significantly enhances the intergranular corrosion resistance of the stainless steel.The stainless steel exhibits uniform corrosion in the nitrate solution.The corrosion layer displays a dual-layer structure,and the corrosion products protecting matrix are present in both the inner and outer layers.The outer layer consists of a mixture of Fe oxides(Fe_(2)O_(3),Fe_(3)O_(4)),NaFeO_(2),and a minor amount of MgFe_(2)O_(4).Conversely,the inner layer is primarily composed of a spinel layer(FeCr_(2)O_(4),MgCr_(2)O_(4))and a thin Cu_(2)O layer.The oxidation of Cu in the inner layer leads to the formation of a dense Cu_(2)O layer,effectively impeding O_(2)-plasma infiltration into the matrix.展开更多
Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-...Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-linked-immunoassay(ELISA)method was developed to determine 3-NT in modified model protein(bovine serum albumin,BSA)and ambient aerosol samples.The nitration degrees(NDs)of BSA in the exposure experiments with different durations were detected by both the ELISA and spectrophotometric methods(i.e.,ND_(ELISA) and ND_(SEC-PDA)),which show good coincidence.The kinetic investigation by both ΔND_(ELISA) and ΔND_(SEC-PDA) in the exposure experiments shows that the rate coefficients(k)of the pseudo-first-order kinetic rate reactions of protein nitration were comparable.These results indicate that direct detection of 3-NT by the ELISA method can be applied for laboratory exposure samples analysis for kinetic studies.Based on the selective detection of 3-NT,ND_(ELISA) provides a promising measure for the assessment of ND in model proteins.3-NT was alsomeasured in PM_(2.5) samples in summer in Guangzhou,southern China,ranging from 10.1 to 404 pg/m^(3),providing clear evidence of protein nitration in ambient aerosols.We further proposed that 3-NT/protein can be used as a proxy to evaluate protein nitration in ambient aerosols.A significant correlationwas observed between 3-NT/protein and O_(3),confirming the crucial role of O_(3) in protein nitration.Our results show that the direct detection of 3-NT by the ELISA method can be more widely applied in the laboratory and field-based studies for understanding the mechanisms of protein nitration.展开更多
The enrichment of low-grade phosphate rock is an important process to realize sustainable support of phosphorus resources. An aqueous solution containing Ca(NO_(3))_(2) and Mg(NO_(3))_(2) is produced during the enrich...The enrichment of low-grade phosphate rock is an important process to realize sustainable support of phosphorus resources. An aqueous solution containing Ca(NO_(3))_(2) and Mg(NO_(3))_(2) is produced during the enrichment of low-grade phosphate rock by leaching of HNO_(3) or calcination coupling with leaching of NH_(4)NO_(3) solution. Preparation liquid fertilizer is a preferential way to utilize it. The liquid−solid phase diagrams of Ca(NO_(3))_(2)-Mg(NO_(3))_(2)-H_(2)O, KNO_(3)-Mg(NO_(3))_(2)-H_(2)O, KNO_(3)-Ca(NO_(3))_(2)-H_(2)O and KNO_(3)-Ca(NO_(3))_(2)-Mg(NO_(3))_(2)-H_(2)O systems at 313.15 K were studied by isothermal dissolution equilibrium method. Two crystallization regions of Ca(NO_(3))_(2)·4H_(2)O and Mg(NO_(3))_(2)·6H_(2)O were observed in the phase diagram of the ternary system Ca(NO_(3))_(2)-Mg(NO_(3))_(2)-H_(2)O, a liquid fertilizer with a maximal total nutrient content of 27.46% and a nutrients ratio of N:Ca:Mg = 8.40:10.37:1 can be formed. A homogenous solution can be formed by mixing Ca(NO_(3))_(2)·4H_(2)O and Mg(NO_(3))_(2)·6H_(2)O. In the ternary system KNO_(3)-Mg(NO_(3))_(2)-H_(2)O, the crystallization regions of KNO_(3), Mg(NO_(3))_(2)·6H_(2)O and the co-crystallization region of KNO_(3) and Mg(NO_(3))_(2)·6H_(2)O were observed. The obtained maximal total nutrient content of liquid fertilizer is 23.32% with the ratio of N:K_(2)O = 1:3.39. In the ternary system KNO_(3)-Ca(NO_(3))_(2)-H_(2)O, the crystallization regions of Ca(NO_(3))_(2)·4H_(2)O and KNO_(3) were observed. The obtained maximal total nutrient content of liquid fertilizer is 38.41% with the ratio of N:K_(2)O:Ca = 1.05:1.18:1. A homogenous solution can also be formed by mixing Ca(NO_(3))_(2)·4H_(2)O and KNO_(3) directly. In the quaternary system KNO_(3)-Ca(NO_(3))_(2)-Mg(NO_(3))_(2)-H_(2)O, the crystallization regions of Ca(NO_(3))_(2)·4H_(2)O, Mg(NO_(3))_(2)·6H_(2)O and KNO_(3) and the co-crystallization region of KNO_(3) and Mg(NO_(3))_(2)·6H_(2)O were observed. The obtained maximal total nutrient content of liquid fertilizer is 38.41% with the ratio of N:K_(2)O:Ca = 1.05:1.18:1. The modified BET model was successfully used to fit the solubility curves. The results can provide a guidance for the formulation of water-soluble fertilizers of N-(K, Ca, Mg).展开更多
Cyclotella cryptica,a model diatom known for its robust adaptability to variable salinity and temperature conditions,is a promising candidate for large-scale biotechnological applications.Nutrient availability,particu...Cyclotella cryptica,a model diatom known for its robust adaptability to variable salinity and temperature conditions,is a promising candidate for large-scale biotechnological applications.Nutrient availability,particularly nitrogen and phosphorus,plays a crucial role in the metabolic activities of microalgae,influencing its industrial utility.Exploring the relationship between these essential nutrients and both the yield and biochemical composition of this microalga is crucial for optimizing cultivation strategies.However,research focusing on the effects of nitrogen and phosphorus on C.cryptica remains limited.We investigated the impacts of varying concentrations of nitrate(0.25-3.96 mmol/L)and phosphate(14.4-229.6μmol/L)on C.cryptica culture by analyzing its growth performance,photosynthetic activity,biochemical composition,and biosilica deposition.Results indicate that C.cryptica exhibited enhanced growth,photosynthetic efficiency,and carotenoid production under higher nutrient concentrations.However,the effects of nitrate on macronutrients composition and fatty acids profile differed from those of phosphate.Specifically,increased nitrate levels resulted in higher concentrations of polyunsaturated fatty acids(PUFAs)at the expense of saturated fatty acids(SFAs),while increased phosphate levels were associated with increased PUFAs and reduced monounsaturated fatty acids(MUFAs).Additionally,biosilica deposition was weakened by elevated nitrate but enhanced by increased phosphate levels.This study improved our understanding of nutrient-mediated regulatory mechanisms in diatoms and contributed valuable data to the broader field of algal biotechnology.Moreover,these findings are expected to advance the development of tailored nutrient management strategies,thereby enhancing the industrial potential of C.cryptica.展开更多
A novel Cu-t-ZrO_(2)catalyst with enhanced electronic metal-support interaction(EMSI)is designed for efficient electrocatalytic conversion of nitrate(NO_(3^(-)))to ammonia(NH_(3)),achieving a remarkable Faradaic effic...A novel Cu-t-ZrO_(2)catalyst with enhanced electronic metal-support interaction(EMSI)is designed for efficient electrocatalytic conversion of nitrate(NO_(3^(-)))to ammonia(NH_(3)),achieving a remarkable Faradaic efficiency and yield rate of 97.54%and 33.64 mg h^(-1)mg_(cat)^(-1),respectively.Electrons are more likely to be transferred from Cu to t-ZrO_(2)at the electron-rich interface due to the lower work function,which promotes the formation of highly active Cu species and facilitates NO_(3^(-))adsorption,ensuring selective conversion into NH_(3).展开更多
This reconnaissance study was carried out in urgency as residents complained of groundwater contamination in a tribal stretch infectedwith chronic kidney disease of unknown etiology in central India where at least 100...This reconnaissance study was carried out in urgency as residents complained of groundwater contamination in a tribal stretch infectedwith chronic kidney disease of unknown etiology in central India where at least 100 people have already died and more than 300 hospitalized.Multi-indexing techniques were used to evaluate groundwater quality for drinking,irrigation,and industrial purposes.The comprehensive water quality index(CWQI)classifies∼52%of the 27 collected samples suitable for drinking,and∼37%partially suitable pending certain treatment.While the relative abundance of chemical parameters stands at Ca^(2+)>Na^(+)>Mg^(2+)>K^(+)for cations and HCO_(3)^(−)>Cl^(−)>NO_(3)^(−)>SO_(4)^(2−)>F^(−)for anions,the groundwater in the area suffers from general hardness,nitrate,and fluoride contamination.It is hypothesized that fluoride ions possibly couplewith excess alkaline earth elements and anions to form metal-complexes inviting Hofmeister phenomena to act in the human kidneys through ingested groundwater.For agricultural water quality assessment,historically developed 10 irrigation indices have been used that classify most groundwater samples suitable for agriculture.Corrosivity indices reveal that the groundwater has moderate to high corrosive affinity.Although the results of the irrigation and corrosivity indices are coherent with CWQI water classes,the use of so many indices based on certain chemical parameters to evaluate water samples for agricultural purposes delivers mixed results and confuses workers about the actual water quality in the field.This calls for the development of a new,robust,and comprehensive standard for appraisal of irrigation water quality that could be used uniformly worldwide.展开更多
Due to the discharge of industrialwastewater,urban domestic sewage,and intensive marine aquaculture tailwater,nitrate(NO_(3)^(−))pollution has emerged as a significant issue in offshore waters.Nitrate pollution affect...Due to the discharge of industrialwastewater,urban domestic sewage,and intensive marine aquaculture tailwater,nitrate(NO_(3)^(−))pollution has emerged as a significant issue in offshore waters.Nitrate pollution affects aquatic life and may interact with other pollutants,leading to comprehensive toxicity.Cadmium(Cd^(2+))is the most widespread metal contaminant,adversely affecting aquatic life in the coastal waters of China.Despite this,few studies have focused on the synergistic toxicity of NO_(3)^(−)and Cd^(2+)in marine organisms.This study conducted a 30-day exposure experiment on marine Japanese flounder(Paralichthys olivaceus)to explore the synergistic toxicity of NO_(3)^(−)and Cd^(2+).Our results demonstrated that the exposure to Cd^(2+)alone induced slight histopathological changes in the liver.However,malformations such as hepatic vacuolar degeneration and sinusoid dilatationwere exacerbated under co-exposure.Moreover,co-exposure induced the downregulation of antioxidants and the upregulation of the product malonaldehyde(MDA)from lipid peroxidation,indicating potent oxidative stress in the liver.The increased mRNA expression of IL-8,TNF-α,and IL-1β,along with the decreased expression level of TGF-β,indicated a synergistic inflammatory response in the organisms.Furthermore,the co-exposure led to an abnormal expression of P53,caspase-3,caspase-9,Bcl-2,and Bax,and disturbed the apoptosis in the liver through TUNEL staining analysis.Overall,our results imply that co-exposure synergistically affects inflammation,redox status,and apoptosis in flounders.Therefore,the findings from this study provide valuable perspectives on the ecological risk assessment of marine teleosts co-exposure to NO_(3)^(−)and Cd^(2+).展开更多
Red mud(RM)is a solid waste generated in the aluminum industry after the extraction of alumina oxide;its multiple elements and higher pH value likely pose a severe threat to the environment after treatment.However,RM&...Red mud(RM)is a solid waste generated in the aluminum industry after the extraction of alumina oxide;its multiple elements and higher pH value likely pose a severe threat to the environment after treatment.However,RM's higher concentrations of metal components,particularly Fe_(2)O_(3)and rare earth elements(REEs),render RM promising for catalytic application.Hence,this work showed an efficient high-speed RM to catalyze electrocatalytic nitrate-to-ammonia reduction reaction(NARR).RM calcined at 500℃(RM-500)exhibited excellent catalytic performance.Faradaic efficiency of ammonia(FENH_(3))in an electrolyte solution containing 1 mol·L^(-1)NO_(3)-achieved a maximum value of 92.3%at-0.8 V(vs.RHE).Additionally,24-h cycle testing and post-reaction PXRD and SEM indicated that the RM-500 electrocatalyst is stable during NARR.The RM-500 demonstrated a high FE of NH_(3)-to-NO_(3)-of 89.7%at 1.85 V(vs.RHE),showing great potential in the ammonia fuel cells technology and achieving the nitrogen cycle.展开更多
Heterotrophic denitrification based on polylactic acid(PLAHD)can remove nitrate effectively,but it is expensive and can't remove phosphate.Autotrophic denitrification based on iron sulfide(ISAD)can simultaneously ...Heterotrophic denitrification based on polylactic acid(PLAHD)can remove nitrate effectively,but it is expensive and can't remove phosphate.Autotrophic denitrification based on iron sulfide(ISAD)can simultaneously remove nitrate and phosphate cost-effectively,but its nitrate rate is slow.So,iron sulfide mineral/polylactic acid mixotrophic biofilter(ISPLAB)was constructed to combine advantages of ISAD and PLAHD.ISPLAB achieved nitrogen and phosphorus removal rates of 98.04%and 94.12%,respectively,at a hydraulic retention time(HRT)of 24 h.The study also revealed that controlling molecular weight(MW)of PLA improved the release of soluble organic matter;adding iron sulfide enhanced the hydrolysis of PLA and precipitated PO_(4)^(3-) of Fe^(2+)/Fe^(3+),thereby facilitated simultaneous nitrogen and phosphorus removal.Microbial community analysis resulted that denitrifying bacterias(Phaeodactylibacter and Methylotenera),sulfur-reducing bacterias(Hyphomicrobium),sulfur-oxidizing bacteria(Denitratisoma),iron-reducing bacteria(Romboutsia)and hydrolyzed bacterias(norank_f_norank_o_1-20 and norank_f_Caldilineaceae)coexisted in the ISPLAB system.Organics and iron sulfide drived the denitrification process in ISPLAB.展开更多
基金supported by the National Key R&D Program of China(No.2017YFC0212501)the Fundamental Research Funds for the Central Universities(No.2021YJSMT09)the research project on deep source apportionment of urban air pollution and pollution control strategies in the core area of the Ili River Valley。
文摘Polycyclic Aromatic Hydrocarbons(PAHs),along with their derivatives nitro-PAHs and oxy-PAHs,are globally recognized toxic pollutants.This research conducted daily PM_(2.5)sampling in winter 2021 at three urban(YNCE,SWP,and NG)and three suburban sites(HC,CTV,and YNE)in the Ili River Valley(IRV).For the first time in the IRV,a comprehensive study on 39 PAHs and derivatives was carried out.The results showed that the average∑_(16)PAHs concentration was 130.21±98.94 ng/m^(3),with 16PAHs constituting the dominant fraction(112.51±86.48 ng/m^(3)).The mean BaP and the total BaP equivalent quotient(TEQ)concentrations were 10.28±8.85 ng/m^(3)and 19.74±16.70 ng/m^(3),respectively.Approximately 88%of the daily BaP averages and 98%of the daily TEQ averages exceeded the national daily average standard of BaP(2.5 ng/m^(3)),indicating severe local BaP pollution.Urban sites had notably higher∑PAHs and TEQ concentrations than suburban sites,attributed to increased vehicular traffic and coal combustion in urban areas.PMF results showed that traffic emissions(32.7%-60.5%),coal combustion(13.9%-24.3%)and secondary formation(14.7%-22.7%)were the primary contributors to∑PAHs.Urban sites experienced a greater influence from traffic,while suburban sites were more impacted by coal and biomass burning.On polluted days,traffic sources’contributions increased significantly at HC,YNE,NG and YNCE sites,and secondary formation sources’contributions grew at CTV and YNCE sites.The sourcedependent BaPeq results underscored the role of secondary-formed PAH derivatives in TEQ.
基金supported by the National Natural Science Foundation of China(No.41671493)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF17030)the National Major Project of the Science and Technology Ministry of China(No.2017ZX07202-004 and 2017X07301002-3)。
文摘Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recent years.In this study,the occurrence,distribution,source,and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry,normal,and flood seasons of 2018.The PAH concentrations ranged from 255 to 7298 ng/L and the NPAH concentrations ranged from not-detected(ND)to 212 ng/L.Among the target analytes,2-nitrofluorene(2-n Flu)was the predominant NPAH,with a detection frequency ranging from 85%to 90%and a maximum concentration of 56.2 ng/L.The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds.In terms of seasonal variation,the highest levels of the NPAHs and PAHs were in the dry season and flood season,respectively.Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion,whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion.The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model.The carcinogenic risk level of the targets ranged from 2.09×10^(-7)to 5.75×10^(-5)and some surface water samples posed a potential health risk.
基金supported by the National Natural Science Foundation of China(No.41907197)the Fundamental Research Funds for Central Public Welfare Scientific Research Institutes of China,Chinese Research Academy of Environmental Sciences(No.2019YSKY-018)+1 种基金the National Key R&D Program of China(No.2019YFC0214800)the Standard System and Key Standards Research of National Ecological Environment Protection and Risk Prevention(No.2020YFC18063)。
文摘Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,formation mechanism,and health risk assessment of them in heating season,particulate matter(PM)were collected in Beijing urban area from December 26,2017 to January 17,2018.PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS).Average daily concentrations of PAHs and NPAHs were(78±54)ng/m^(3)and(783±684)pg/m^(3),respectively.The concentrations of them were significantly higher at nighttime than at daytime,and NPAHs concentrations were 1-2 orders of magnitude lower than PAHs concentrations.In the heating season,the dominant species of PAHs include benzo[b]fluoranthene,fluoranthene,pyrene,and chrysene,while 9-nitroanthracene,2+3-nitrofluoranthene,and 2-nitropyrene were dominant species for NPAHs.NPAHs were found to have a single peak during heating and to be primarily distributed in the 0.4-0.7μm particle size.Primary emissions such as biomass burning,coal combustion,and traffic emissions were the major sources of PAHs.NPAHs were produced by the primary source of vehicle emissions and the secondary reaction triggered by OH radicals,as well as biomass burning during daytime.According to the health risk assessment,the total carcinogenic risk was higher in adults than in children.While upon oral ingestion,the carcinogenic risk in children was higher than that of adults,but the risk of adults was higher than children through skin contact and respiratory inhalation.
基金supported by the National Natural Science Foundation of China (No. 40971257,41171365)the Environmental Nonprofit Research and Special Project of China (No. 201009004)the Program for Changjiang Scholars and Innovative Research Team in University (No.IRT0941)
文摘Intensive daytime and nighttime sampling was carried out from 23 Oct to 31 Dec 2008 to investigate the occurrence of nitrated polycyclic aromatic hydrocarbons （NPAHs） in PM1o at a roadside site in Xiamen, China. At the same time, six PMt0 samples were collected from a nearby roadway tunnel for comparison. Six NPAHs, namely 9-nitroanthracene, 2- and 3-nitrofluoranthene, 1- nitropyrene, 7-nitrobenz[a]anthracene, and 6-nitrobenzo[a]pyrene, were identified and quantified using GC/MS in negative ion chemical ionization mode. The average total concentration of six NPAHs （~NPAHs） in the cold season （26 Nov-31 Dec） was 2.3 （daytime） and 9.9 （nighttime） times higher than those in the warm season. Significant statistical difference （p 〈 0.01, 2-tailed） of ∑NPAHs between daytime and nighttime was found during both the warm and cold seasons. NPAHs were significantly positively correlated with their parent PAHs and nitrogen dioxide but negatively correlated with ambient temperature. The ratio of 2 ＋ 3-nitrofluoranthene to 1- nitropyrene exhibited a similar diurnal pattern as ZNPAHs and was generally greater than 5, indicating the importance of secondary atmospheric formation. The diurnal variations of NPAHs were all influenced by the diurnal variations of PAHs, nitrogen dioxide, sunlight, and temperature. The daily inhalable exposure to the six NPAHs in the tunnel was much higher than the roadside values in the warm season but only slightly higher than those in the cold season.
基金financially supported by the National Natural Science Foundation of China (No. 41977341)Natural Science Foundation of Zhejiang Province, China (No. LGF21B070007)Research Center for Air Pollution and Health, Zhejiang University (No. I21405-11)
文摘Air pollutants can potentially lead to nitration of allergic proteins,thus promoting sensitization of these allergens.However,little is currently known about the nitration status of house dust mite(HDM)allergens.We identified the occurrence of nitrated products of two major HDM allergens Der f 1 and Der p 1 in dust samples collected from college dormitories in eastern China and assessed their associated health risk.The results showed that both non-nitrated and nitrated forms of the two allergens were detected in the dust in the range of non-detected(ND)-10.6,1.44-15.4,ND-22.4,ND-7.28μg/g for non-nitrated Der f 1,nitrated Der f 1,non-nitrated Der p 1 and nitrated Der p 1,respectively.The median rates of nitration were determined as 74.0%for Der f 1 and 20.4% for Der p 1 at consideration of one nitration site.Further analysis reveals that the levels of HDM allergens and their nitrated products were found to be generally higher during winter,in dormitories of lower altitude and with female occupants.Furthermore,the calculated risk indexes were at considerably high levels.Our findings suggest that nitrated HDM allergens have already accumulated in the environment at such significant levels and their associated health risk calls for our immediate attention.
文摘The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has been employed as a coating agent.The SEM micrographs revealed distinct features of both pure AN and NC,contrasting with the irregular granular surface topography of the coated AN particles,demonstrating the adherence of NC on the AN surface.Structural analysis via infrared spectroscopy(IR)demonstrated a successful association of AN and NC,with slight shifts observed in IR bands indicating interfacial interactions.Powder X-ray Diffraction(PXRD)analysis further elucidated the structural changes induced by the coating process,revealing that the NC coating altered the crystallization pattern of its pure form.Thermal analysis demonstrates distinct profiles for pure and coated AN,for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6℃,and 36%,respectively.Furthermore,the presence of NC coating alters the intermolecular forces within the composite system,leading to a reduction in melting enthalpy of coated AN by~39%compared to pure AN.The thermal decomposition analysis shows a two-step thermolysis process for coated AN,with a significant increase in the released heat by about 78%accompanied by an increase in the activation barrier of NC and AN thermolysis,demonstrating a stabilized reactivity of the AN-NC particles.These findings highlight the synergistic effect of NC coating on AN particles,which contributed to a structural and reactive stabilization of both AN and NC,proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations.
文摘Nitrate contamination of groundwater is a worldwide problem, particularly in agricultural countries. Exposure to high levels of nitrates in groundwater can have adverse effects on the health of residents who use groundwater for drinking. This study aims to assess the health risk associated with the ingestion of nitrates in well water in the town of M’bahiakro. Health risk maps were created on the basis of hazard quotients (HQ) using the US Environmental Protection Agency (USEPA) health risk assessment model. The results indicate that residents of the Koko, Dougouba and Baoulekro neighbourhoods, whatever their age, are potentially exposed to the toxic effects of NO3−during their daily intake of nitrate-contaminated well water, with reference to hazard quotients (HQ) greater than 1. Nitrate concentrations in the groundwater should therefore be controlled in order to prevent their harmful effects on the health of the population and guarantee its use in rice-growing activities in M’Bahiakro.
基金National Natural Science Foundation of China (52371228, 52402045)fund of Key Laboratory of Advanced Materials of Ministry of Education(Advmat-2414)。
文摘Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution issues.We report a CuO nanoparticles incorporated on nitrogen-doped porous carbon (CuO@NC) catalyst for NO_(3)-RR.Part of Cu(Ⅱ) is reduced to Cu(Ⅰ) during the NO_(3)-RR process to construct Cu(Ⅰ)-Cu(Ⅱ) pairs,confirmed by in situ X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.Density functional theory (DFT) calculations indicated that the formation of Cu(Ⅰ) could provide a reaction path with smaller energy barrier for NO_(3)-RR,while Cu(Ⅱ) effectively suppressed the competition of hydrogen evolution reaction (HER).As a result,CuO@NC catalyst achieved a Faradaic efficiency of 84.2% at -0.49 V versus reversible hydrogen electrode (RHE),and a NH_(3)yield rate of 17.2 mg h^(-1)mg^(-1)cat.at -0.79 V vs.RHE,higher than the HaberBosch process (<3.4 g h^(-1)g^(-1)cat.).This work may open a new avenue for effective NO_(3)-RR by modulating oxidation states.
基金support from the National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (Earth Lab)sponsored by the National Natural Science Foundation of China (Grant Nos. 42175132, 92044303, and 42205119)+2 种基金the National Key R&D Program (Grant Nos. 2020YFA0607802 and 2022YFC3703003)the CAS Information Technology Program (Grant No. CAS-WX2021SF-0107-02)the fellowship of China Postdoctoral Science Foundation (Grant No. 2022M723093)
文摘Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategies.A high-resolution PM_(2.5) chemical composition dataset(CAQRA-aerosol)is developed in this study,which provides hourly maps of organic carbon,black carbon,ammonium,nitrate,and sulfate in China from 2013 to 2020 with a horizontal resolution of 15 km.This paper describes the method,access,and validation results of this dataset.It shows that CAQRA-aerosol has good consistency with observations and achieves higher or comparable accuracy with previous PM_(2.5) composition datasets.Based on CAQRA-aerosol,spatiotemporal changes of different PM_(2.5) compositions were investigated from a national viewpoint,which emphasizes different changes of nitrate from other compositions.The estimated annual rate of population-weighted concentrations of nitrate is 0.23μg m^(−3)yr^(−1) from 2015 to 2020,compared with−0.19 to−1.1μg m^(−3)yr^(−1) for other compositions.The whole dataset is freely available from the China Air Pollution Data Center(https://doi.org/10.12423/capdb_PKU.2023.DA).
基金supported by the National Natural Science Foundation of China(51609247)the Henan Provincial Natural Science Foundation,China(222300420589,202300410553)+4 种基金the Central Public-interest Scientific Institution Basal Research Fund,China(FIRI2022-22)the Science&Technology Fundamental Resources Investigation Program,China(2022FY101601)the Science and Technology Project of Xinxiang City,Henan Province,China(GG2021024)the Major Special Science and Technology Project of Henan Province,China(221100110700)the Joint Fund of Science and Technology Research and Development Plan of Henan Province,China(Superior Discipline Cultivation)(222301420104)。
文摘Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.
基金supported by Natural Science Foundation of Shandong Province(ZR2021MB075)Fundamental Research Funds for the Central Universities,Ocean University of China(202461021).
文摘The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation and oxygen evolution competition,sluggish kinetics,low Faradaic efficiency,and limited nitrate yields.In this work,a novel two-dimensional(2D)layered MOF Mn-BCPPy(H_(2)BCPPy=3,5-di(4'-carboxyphenyl)pyridine)has been successfully synthesized.The framework is composed of a rod-manganese motifs and possesses abundant active sites including open metal sites(OMSs)and Lewis base sites(LBSs).The Mn-BCPPy is the first MOF catalyst applied in electrocatalytic NOR which NO_(3)^(-)exhibited relatively high activity with a yield of 99.75μg/(h·mg)and a Faraday efficiency(FE)of 32.09%.Furthermore,it can be used as fluorescent sensor for selectively and sensitively detect nitrofuran antibiotics(NFs).Therefore,this work explores the application of MOF materials in the field of electrocatalytic NOR,which reveals that manganese-based MOFs have great potential prospects.
基金Science and Technology Program Project of Gansu Province(21ZD3GB001)。
文摘A static corrosion experiment of 347H stainless steel alloyed with elements Cu and Mo was carried out in a nitrate molten salt(60%NaNO_(3)+40%KNO_(3))at 565℃ for 720 h.The effects of elements Cu and Mo on the corrosion resistance of 347H stainless steel in molten salt were investigated by analyzing the phase composition,microstructure and chemical composition of the corrosion products.The results show that the grain refinement induced by element Mo imparts the stainless steel with optimal corrosion resistance at a medium grain size.Furthermore,the formation of MoC significantly enhances the intergranular corrosion resistance of the stainless steel.The stainless steel exhibits uniform corrosion in the nitrate solution.The corrosion layer displays a dual-layer structure,and the corrosion products protecting matrix are present in both the inner and outer layers.The outer layer consists of a mixture of Fe oxides(Fe_(2)O_(3),Fe_(3)O_(4)),NaFeO_(2),and a minor amount of MgFe_(2)O_(4).Conversely,the inner layer is primarily composed of a spinel layer(FeCr_(2)O_(4),MgCr_(2)O_(4))and a thin Cu_(2)O layer.The oxidation of Cu in the inner layer leads to the formation of a dense Cu_(2)O layer,effectively impeding O_(2)-plasma infiltration into the matrix.
基金supported by the National Natural Science Foundation of China(No.41975156).
文摘Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-linked-immunoassay(ELISA)method was developed to determine 3-NT in modified model protein(bovine serum albumin,BSA)and ambient aerosol samples.The nitration degrees(NDs)of BSA in the exposure experiments with different durations were detected by both the ELISA and spectrophotometric methods(i.e.,ND_(ELISA) and ND_(SEC-PDA)),which show good coincidence.The kinetic investigation by both ΔND_(ELISA) and ΔND_(SEC-PDA) in the exposure experiments shows that the rate coefficients(k)of the pseudo-first-order kinetic rate reactions of protein nitration were comparable.These results indicate that direct detection of 3-NT by the ELISA method can be applied for laboratory exposure samples analysis for kinetic studies.Based on the selective detection of 3-NT,ND_(ELISA) provides a promising measure for the assessment of ND in model proteins.3-NT was alsomeasured in PM_(2.5) samples in summer in Guangzhou,southern China,ranging from 10.1 to 404 pg/m^(3),providing clear evidence of protein nitration in ambient aerosols.We further proposed that 3-NT/protein can be used as a proxy to evaluate protein nitration in ambient aerosols.A significant correlationwas observed between 3-NT/protein and O_(3),confirming the crucial role of O_(3) in protein nitration.Our results show that the direct detection of 3-NT by the ELISA method can be more widely applied in the laboratory and field-based studies for understanding the mechanisms of protein nitration.
基金support from the National Key Research and Development Program of China(2022YFC2904704)the Fundamental Research Funds for the Central Universities(SCU2024D009)。
文摘The enrichment of low-grade phosphate rock is an important process to realize sustainable support of phosphorus resources. An aqueous solution containing Ca(NO_(3))_(2) and Mg(NO_(3))_(2) is produced during the enrichment of low-grade phosphate rock by leaching of HNO_(3) or calcination coupling with leaching of NH_(4)NO_(3) solution. Preparation liquid fertilizer is a preferential way to utilize it. The liquid−solid phase diagrams of Ca(NO_(3))_(2)-Mg(NO_(3))_(2)-H_(2)O, KNO_(3)-Mg(NO_(3))_(2)-H_(2)O, KNO_(3)-Ca(NO_(3))_(2)-H_(2)O and KNO_(3)-Ca(NO_(3))_(2)-Mg(NO_(3))_(2)-H_(2)O systems at 313.15 K were studied by isothermal dissolution equilibrium method. Two crystallization regions of Ca(NO_(3))_(2)·4H_(2)O and Mg(NO_(3))_(2)·6H_(2)O were observed in the phase diagram of the ternary system Ca(NO_(3))_(2)-Mg(NO_(3))_(2)-H_(2)O, a liquid fertilizer with a maximal total nutrient content of 27.46% and a nutrients ratio of N:Ca:Mg = 8.40:10.37:1 can be formed. A homogenous solution can be formed by mixing Ca(NO_(3))_(2)·4H_(2)O and Mg(NO_(3))_(2)·6H_(2)O. In the ternary system KNO_(3)-Mg(NO_(3))_(2)-H_(2)O, the crystallization regions of KNO_(3), Mg(NO_(3))_(2)·6H_(2)O and the co-crystallization region of KNO_(3) and Mg(NO_(3))_(2)·6H_(2)O were observed. The obtained maximal total nutrient content of liquid fertilizer is 23.32% with the ratio of N:K_(2)O = 1:3.39. In the ternary system KNO_(3)-Ca(NO_(3))_(2)-H_(2)O, the crystallization regions of Ca(NO_(3))_(2)·4H_(2)O and KNO_(3) were observed. The obtained maximal total nutrient content of liquid fertilizer is 38.41% with the ratio of N:K_(2)O:Ca = 1.05:1.18:1. A homogenous solution can also be formed by mixing Ca(NO_(3))_(2)·4H_(2)O and KNO_(3) directly. In the quaternary system KNO_(3)-Ca(NO_(3))_(2)-Mg(NO_(3))_(2)-H_(2)O, the crystallization regions of Ca(NO_(3))_(2)·4H_(2)O, Mg(NO_(3))_(2)·6H_(2)O and KNO_(3) and the co-crystallization region of KNO_(3) and Mg(NO_(3))_(2)·6H_(2)O were observed. The obtained maximal total nutrient content of liquid fertilizer is 38.41% with the ratio of N:K_(2)O:Ca = 1.05:1.18:1. The modified BET model was successfully used to fit the solubility curves. The results can provide a guidance for the formulation of water-soluble fertilizers of N-(K, Ca, Mg).
基金Supported by the National Natural Science Foundation of China(No.31902370)the Ningbo Public Welfare Science and Technology Program(No.2022S161)the Zhejiang Provincial Natural Science Foundation of China(No.LY22C190001)。
文摘Cyclotella cryptica,a model diatom known for its robust adaptability to variable salinity and temperature conditions,is a promising candidate for large-scale biotechnological applications.Nutrient availability,particularly nitrogen and phosphorus,plays a crucial role in the metabolic activities of microalgae,influencing its industrial utility.Exploring the relationship between these essential nutrients and both the yield and biochemical composition of this microalga is crucial for optimizing cultivation strategies.However,research focusing on the effects of nitrogen and phosphorus on C.cryptica remains limited.We investigated the impacts of varying concentrations of nitrate(0.25-3.96 mmol/L)and phosphate(14.4-229.6μmol/L)on C.cryptica culture by analyzing its growth performance,photosynthetic activity,biochemical composition,and biosilica deposition.Results indicate that C.cryptica exhibited enhanced growth,photosynthetic efficiency,and carotenoid production under higher nutrient concentrations.However,the effects of nitrate on macronutrients composition and fatty acids profile differed from those of phosphate.Specifically,increased nitrate levels resulted in higher concentrations of polyunsaturated fatty acids(PUFAs)at the expense of saturated fatty acids(SFAs),while increased phosphate levels were associated with increased PUFAs and reduced monounsaturated fatty acids(MUFAs).Additionally,biosilica deposition was weakened by elevated nitrate but enhanced by increased phosphate levels.This study improved our understanding of nutrient-mediated regulatory mechanisms in diatoms and contributed valuable data to the broader field of algal biotechnology.Moreover,these findings are expected to advance the development of tailored nutrient management strategies,thereby enhancing the industrial potential of C.cryptica.
基金supported by the Natural Scientific Foundation of China(Nos.22127803,22174110,22203050)Natural Scientific Foundation of Shandong(No.ZR2022QB002)China Postdoctoral Science Foundation(No.2020T130331)。
文摘A novel Cu-t-ZrO_(2)catalyst with enhanced electronic metal-support interaction(EMSI)is designed for efficient electrocatalytic conversion of nitrate(NO_(3^(-)))to ammonia(NH_(3)),achieving a remarkable Faradaic efficiency and yield rate of 97.54%and 33.64 mg h^(-1)mg_(cat)^(-1),respectively.Electrons are more likely to be transferred from Cu to t-ZrO_(2)at the electron-rich interface due to the lower work function,which promotes the formation of highly active Cu species and facilitates NO_(3^(-))adsorption,ensuring selective conversion into NH_(3).
文摘This reconnaissance study was carried out in urgency as residents complained of groundwater contamination in a tribal stretch infectedwith chronic kidney disease of unknown etiology in central India where at least 100 people have already died and more than 300 hospitalized.Multi-indexing techniques were used to evaluate groundwater quality for drinking,irrigation,and industrial purposes.The comprehensive water quality index(CWQI)classifies∼52%of the 27 collected samples suitable for drinking,and∼37%partially suitable pending certain treatment.While the relative abundance of chemical parameters stands at Ca^(2+)>Na^(+)>Mg^(2+)>K^(+)for cations and HCO_(3)^(−)>Cl^(−)>NO_(3)^(−)>SO_(4)^(2−)>F^(−)for anions,the groundwater in the area suffers from general hardness,nitrate,and fluoride contamination.It is hypothesized that fluoride ions possibly couplewith excess alkaline earth elements and anions to form metal-complexes inviting Hofmeister phenomena to act in the human kidneys through ingested groundwater.For agricultural water quality assessment,historically developed 10 irrigation indices have been used that classify most groundwater samples suitable for agriculture.Corrosivity indices reveal that the groundwater has moderate to high corrosive affinity.Although the results of the irrigation and corrosivity indices are coherent with CWQI water classes,the use of so many indices based on certain chemical parameters to evaluate water samples for agricultural purposes delivers mixed results and confuses workers about the actual water quality in the field.This calls for the development of a new,robust,and comprehensive standard for appraisal of irrigation water quality that could be used uniformly worldwide.
基金supported by the National Natural Science Foundation of China(No.32202963)the Natural Science Foundation of Jiangsu Province(No.BK20220681)+3 种基金the Doctoral Program of Entrepreneurship and Innovation in Jiangsu Province(No.JSSCBS20221625)the Scientific Research Foundation Program of Jiangsu Ocean University(No.KQ22009)the Undergraduate Innovation&Entrepreneurship Training Program of Jiangsu Province,China(No.SY202411641631001)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX2023-112).
文摘Due to the discharge of industrialwastewater,urban domestic sewage,and intensive marine aquaculture tailwater,nitrate(NO_(3)^(−))pollution has emerged as a significant issue in offshore waters.Nitrate pollution affects aquatic life and may interact with other pollutants,leading to comprehensive toxicity.Cadmium(Cd^(2+))is the most widespread metal contaminant,adversely affecting aquatic life in the coastal waters of China.Despite this,few studies have focused on the synergistic toxicity of NO_(3)^(−)and Cd^(2+)in marine organisms.This study conducted a 30-day exposure experiment on marine Japanese flounder(Paralichthys olivaceus)to explore the synergistic toxicity of NO_(3)^(−)and Cd^(2+).Our results demonstrated that the exposure to Cd^(2+)alone induced slight histopathological changes in the liver.However,malformations such as hepatic vacuolar degeneration and sinusoid dilatationwere exacerbated under co-exposure.Moreover,co-exposure induced the downregulation of antioxidants and the upregulation of the product malonaldehyde(MDA)from lipid peroxidation,indicating potent oxidative stress in the liver.The increased mRNA expression of IL-8,TNF-α,and IL-1β,along with the decreased expression level of TGF-β,indicated a synergistic inflammatory response in the organisms.Furthermore,the co-exposure led to an abnormal expression of P53,caspase-3,caspase-9,Bcl-2,and Bax,and disturbed the apoptosis in the liver through TUNEL staining analysis.Overall,our results imply that co-exposure synergistically affects inflammation,redox status,and apoptosis in flounders.Therefore,the findings from this study provide valuable perspectives on the ecological risk assessment of marine teleosts co-exposure to NO_(3)^(−)and Cd^(2+).
基金supported by grants from the National Natural Science Foundation of China (22178339)2023 Innovation-driven Development Special Foundation of Guangxi(AA23023021)the Hundred Talents Program (A) of the Chinese Academy of Sciences
文摘Red mud(RM)is a solid waste generated in the aluminum industry after the extraction of alumina oxide;its multiple elements and higher pH value likely pose a severe threat to the environment after treatment.However,RM's higher concentrations of metal components,particularly Fe_(2)O_(3)and rare earth elements(REEs),render RM promising for catalytic application.Hence,this work showed an efficient high-speed RM to catalyze electrocatalytic nitrate-to-ammonia reduction reaction(NARR).RM calcined at 500℃(RM-500)exhibited excellent catalytic performance.Faradaic efficiency of ammonia(FENH_(3))in an electrolyte solution containing 1 mol·L^(-1)NO_(3)-achieved a maximum value of 92.3%at-0.8 V(vs.RHE).Additionally,24-h cycle testing and post-reaction PXRD and SEM indicated that the RM-500 electrocatalyst is stable during NARR.The RM-500 demonstrated a high FE of NH_(3)-to-NO_(3)-of 89.7%at 1.85 V(vs.RHE),showing great potential in the ammonia fuel cells technology and achieving the nitrogen cycle.
基金supported by the National Key Research and Development Program of China(No.2021YFC3201505-02)Shenzhen Science and Technology Plan Collaborative Innovation Project-Undertake Major National Science and Technology Projects of China(No.CJGJZD2020061710260200).
文摘Heterotrophic denitrification based on polylactic acid(PLAHD)can remove nitrate effectively,but it is expensive and can't remove phosphate.Autotrophic denitrification based on iron sulfide(ISAD)can simultaneously remove nitrate and phosphate cost-effectively,but its nitrate rate is slow.So,iron sulfide mineral/polylactic acid mixotrophic biofilter(ISPLAB)was constructed to combine advantages of ISAD and PLAHD.ISPLAB achieved nitrogen and phosphorus removal rates of 98.04%and 94.12%,respectively,at a hydraulic retention time(HRT)of 24 h.The study also revealed that controlling molecular weight(MW)of PLA improved the release of soluble organic matter;adding iron sulfide enhanced the hydrolysis of PLA and precipitated PO_(4)^(3-) of Fe^(2+)/Fe^(3+),thereby facilitated simultaneous nitrogen and phosphorus removal.Microbial community analysis resulted that denitrifying bacterias(Phaeodactylibacter and Methylotenera),sulfur-reducing bacterias(Hyphomicrobium),sulfur-oxidizing bacteria(Denitratisoma),iron-reducing bacteria(Romboutsia)and hydrolyzed bacterias(norank_f_norank_o_1-20 and norank_f_Caldilineaceae)coexisted in the ISPLAB system.Organics and iron sulfide drived the denitrification process in ISPLAB.
