Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key fac...Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key factors in anammox bacteria enrichment.This study investigated the mechanisms driving anammox bacteria enrichment in lab-scale simulated CWs treating high-nitrogen wastewater,focusing on bacterial community re-sponses across wetland layers with various strategies,including continuous up-flow influent,nitrogen loading increase,effluent recirculation,intermittent influent,and anammox bacteria inoculation.Results showed that total relative and absolute abundances of anammox bacteria ranged from 0.77%to 12.50%and from 0.13 to 6.46×10^(7) copies/g,respectively.Dissolved oxygen and pH had significant positive correlations with the absolute abundance of anammox bacteria,while organic matter and nitrate negatively impacted their relative abundance.Permutational multivariate analysis of variance indicated that spatial heterogeneity explained more variation in anammox bacteria abundance(43.44%)compared to operational strategies(8.58%).In terms of microbial interactions,60 dominant species exhibited potential correlations with anammox bacteria,comprising 170 interactions(105 positive and 65 negative),which suggested that anammox bacteria generally foster cooperative relationships with dominant bacteria.Notably,significant interspecies interactions were observed between Candidatus Kuenenia(dominant anammox bacteria in CWs)and species within the genera Chitinivibrio-nia and Anaerolineaceae,suggesting that microbial interactions primarily manifest as indirect facilitative effects rather than direct mutualistic relationships.Given that the Normalized Stochasticity Ratio in CWs were<50%,this study inferred that environmental gradients have greater influence on anammox bacteria than microbial interactions.展开更多
Obtaining the sulfonamides(SAs)concentrations in the water body and sediment bulk was a prerequisite to reveal their transport and partitioning behavior in sediment-water environments and accurately assess their ecolo...Obtaining the sulfonamides(SAs)concentrations in the water body and sediment bulk was a prerequisite to reveal their transport and partitioning behavior in sediment-water environments and accurately assess their ecological risk.In the present study,the influences of multifactor interactions on the performance of o-DGTs with XAD-18 binding gels were analyzed by central combination experiments and response surfaces analysis,in which the target compounds were 9 SAs.The results indicated that dissolved organic matter(DOM),pH,and suspended particulate matter(SS)had significant effects on the o-DGT sampling,whereas this o-DGT was independent of the ionic strength(IS).Concentning the composite influence of the four factors,the interaction between DOM and SS posed the most significant effect on all 9 SAs compounds.Subsequently,an o-DGT and DIFSmodel was applied to explore the SAs migration between the water-sediments interface.The difference between desorption rate(k_(b))and adsorption rates(k_(f))values suggested that the kinetics of SAs was dominated by adsorption.Moreover,the short-term sediment-water partitioning of SAs was clarified on the basis of distribution coefficient(K_(dl))for the labile SAs,among which the sulfadiazine(SDZ)had the largest labile pool.The ability of sediments to release SAs to the liquid phase as a sink was determined by response time(T_(c)).Among the 9 SAs,the longterm release of soseulfamethoxypyridazine(SMP)from the solid phase of sediments would have a potential risk to the aquatic environment,to which more attention should be paid in the future.展开更多
Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films f...Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films from fruits and vegetables,using alginate as a binding agent.Using a completely randomized design,seven experimental sets were prepared with carrots,Kimju guava,and Namwa banana peel fibers as the primary materials and alginate as the secondary material at three levels:1.2,1.8,and 2.4 by weight.The solution technique was employed to create the samples.Upon testing mechanical and physical properties,experimental set 3,consisting of 60%guava and 1.8%alginate,emerged as the optimal ratio.This combination exhibited favorable physical properties,including a thickness of 0.26±0.02 mm,meeting the standards for food packaging films.Additionally,the tensile strength was 0.50±0.01 N/m²,and the elongation at break was 55.60±0.44%.Regarding chemical properties,the moisture content of 5.64±0.03%fell within the acceptable range for dried food.Furthermore,a 30-day soil burial test revealed that the sample from experimental set 3 exhibited the highest degradation rate.In conclusion,these findings suggest that guava can be a promising raw material for producing biodegradable plastics suitable for packaging applications.展开更多
Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-me...Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-ments in karst hydrology,significant gaps remain in long-term trends,underlying processes,and quantitative effects of environmental changes.This is especially true in areas like the Wujiang River(WJ)in China,where human activities such as reservoir construction and land use/cover changes have accelerated hydrochemical changes.We combined recent and historical monitoring data to provide a detailed analysis of the spatial and temporal characteristics,evolution,and controlling factors of major ions in WJ.These findings are important for local water management and contribute to global efforts to manage similar karst systems facing human-induced pressures.Our research shows clear seasonal differences in solute concentrations,with higher levels during the dry season.WJ’s water is rich in calcium,with Ca-HCO_(3) ion pairs being the most common.Reservoir monitor-ing stations show much higher levels of NO_(3)^(−)and SO_(4)^(2−)compared to river-type stations,likely due to longer hydraulic retention time and increased acid deposition.The study confirms the significant role of pH and water temperature in rock weathering processes.Land use/cover changes were identified as the primary drivers of solute variations(46.37%),followed by lithology(13.92%)and temperature(8.35%).Over the past two decades,in-tense carbonate weathering has been observed,especially during wet seasons.Among karstic provinces,Guizhou Province stands out with the highest ion concentrations,indicative of its extensive karst coverage and heightened weathering processes.展开更多
Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electro...Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.展开更多
Pedogenic carbonates, found extensively in arid and semiarid regions, are important in revealing regional climatic and environmental changes as well as the carbon cycle. In addition, stable carbon and oxygen isotopic ...Pedogenic carbonates, found extensively in arid and semiarid regions, are important in revealing regional climatic and environmental changes as well as the carbon cycle. In addition, stable carbon and oxygen isotopic compositions of pedogenic carbonates have been used to rebuild paleoecology (biomass and vegetation) and to estimate paleotemperature and paleoprecipitation during past geological time. By utilizing the stable carbon and oxygen isotopic compositions (δ13C and (δ18O) of secondary nodules in Ustic Vertisols, this study looked into the climatic and environmental changes in the dry valleys of the Yuanmou Basin, Yunnan Province, in southwestern China. The results showed that during the early Holocene, a warm-humid or hot-humid climate existed in the Yuanmou Basin, but since then fluctuations in climate have occurred, with a dry climate prevailing. A highly significant correlation (r = 0.92, n = 9) between δ13C and δ18O values of carbonates illustrated that there had been a continual shifting between cold-humid and warm-dry climates in southwestern China including the Yuanmou Basin since the early Holocene.展开更多
The bottom ash and fly ash from the co-combustion of wood residues and peat at a bubbling fluidised bed boiler（296 MW） contained only quartz（SiO_2）, microcline（KAl Si_3O_8） and albite（NaAlSi_3O_8）. Thus, X-ray...The bottom ash and fly ash from the co-combustion of wood residues and peat at a bubbling fluidised bed boiler（296 MW） contained only quartz（SiO_2）, microcline（KAl Si_3O_8） and albite（NaAlSi_3O_8）. Thus, X-ray powder diffraction（XRD） was not useful for clarifying the difference in the release of associated heavy metals from ash matrices. In order to assess the release of heavy metals from ashes under changing environmental conditions, they were sequentially extracted and fractionated by the BCR-procedure into acid soluble/exchangeable（CH_3COOH）, reducible（NH_2OH-HCl） and oxidizable（H_2O_2/CH_3COONH_4） phases. The CH_3 COOH extractable fraction in conjunction with the total heavy metals concentrations were used to calculate the risk assessment code values for heavy metals leaching from the ash matrix. The leaching studies indicate that the heavy metals in the bottom ash and fly ash are bound to different fractions with different strengths. From the environmental and utilization perspectives, heavy metals in ashes posed different levels of environmental contamination risk. Only As in the bottom ash posed a very high risk. High risk metals were Cd in the bottom ash as well as As, Cd and Se in the fly ash.展开更多
With rapid economy growth,building energy consumption in China has been gradually increased.The energy consumption and indoor environmental quality of 51 office buildings in Hainan Province,a hot and humid area,were s...With rapid economy growth,building energy consumption in China has been gradually increased.The energy consumption and indoor environmental quality of 51 office buildings in Hainan Province,a hot and humid area,were studied through collection of verified data in site visits and field tests.The result revealed that,electricity accounted for 99.79% of the total energy consumption,natural gas 0.17%,and diesel 0.04%.The air conditioning dominated the energy use with a share of 43.18%,equipment in the particular areas 26.90%,equipment in the office rooms 11.95%,lighting system 8.67%,general service system 7.57%,and miscellaneous items 1.73%.Statistical method including six indicators obtained the energy consumption benchmark with upper limit of 98.31 kW-h/m2 and lower limit of 55.26 kW-h/m2.According to ASHRAE standard(comfortable standard) and GB/T 18883-2002(acceptable standard),the indoor environmental quality of 51 sampled office buildings was classified into three ranks:good,normal and bad.With benchmark of building energy consumption combined with indoor environmental quality,it was found that only 3.92% of sampled buildings can be identified as the best performance buildings with low energy consumption and advanced indoor environmental quality,and the buildings classified into normal level accounted for the maximum ratio.展开更多
Human exposure to toxic metals is on the increase especially in the developing world;this is compounded by the almost unavoidable application of the metals domestically and industrially and their implication in severa...Human exposure to toxic metals is on the increase especially in the developing world;this is compounded by the almost unavoidable application of the metals domestically and industrially and their implication in several genetic defects, aging and some chronic illnesses including Autism Spectrum Disorders (ASD). This study investigated the concentration of toxic metals (Pb and V) and micro-essential elements (Cu and Se) in children with ASD and controls in Nigeria towards establishing their possible associations with the aetiopathogenesis of ASD. Eight children clinically diagnosed by Paediatric Neurologist and Child Psychiatrist for ASD using DMS-IV and fifteen apparently healthy children (age range 2 - 12 years) were recruited as cases and controls respectively. Plasma levels of Pb, V, Cu and Se were analyzed using Induction ICP-MS. Results were analyzed using students t-test. The mean plasma lead and vanadium levels were (7.92 ± 1.30 μg/dl;1.07 ± 0.22 μg/dl) and (6.83 ± 0.72 μg/dl;2.59 ± 0.48 μg/dl) in children with ASD and in controls respectively. The result showed that blood lead level in ASD was slightly increased but not significant when compared with control (p < 0.433). On the other hand, plasma vanadium concentration in ASD was significantly reduced (1.07 ± 0.22 μg/dl) when compared with control (2.59 ± 0.48 μg/dl) (P < 0.038). Mean plasma copper was similar in all participants (1.98 ± 0.13, 2.23 ± 0.12) but selenium concentrations were significantly reduced (0.37 ± 0.05 mg/L;0.57 ± 0.02 mg/L) in ASD relative to controls respectively. Given the physiological functions of vanadium and selenium, the observed reduced levels of the two elements in children with ASD may account for the speech and other neurological dysfunctions of the brain in ASD.展开更多
Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kineti...Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kinetics still require improvement.Encouraged by the excellent electrochemical performance of titanium-based anode materials,here,we present a novel titanium vanadate@carbon(TVO@C)material as anode for SIBs.Our TVO@C material is synthesized via a facile coprecipitation method,with the following annealing process in an acetylene atomosphere.The opened ion channel and the oxygen vacancies within TVO@C facilitate the diffusion of Na^(+) ions,reducing their diffusion barrier.Thus,an ultrahigh rate of 100 A g^(-1)and long life of 10,000 cycles have been achieved.Furthermore,the TVO@C electrode exhibits stable performance,not only at room temperature,but also at temperatures as low as 20 C.The TVO@CjjNa_(3)V_(2)(PO_(4))_(3)@C full cells have also achieved stable discharge/charge for 500 cycles.It is believed that this strategy provides new insight into the development of advanced electrodes and provides a new opportunity for constructing novel high rate electrodes.展开更多
Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influen...Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated.This work concentrated on the potential evolution of soil microbiomes and their effects on PHC dissipation within the Suaeda salsa(L.)Pall.planting system in a pot experiment.Two representative compounds,polycyclic aromatic hydrocarbons(PAHs)and n-alkanes,were used as target PHCs.The findings revealed a significant efficiency in the dissipation of PHCs in soil with Suaeda salsa cultivation,particularly with respect to n-alkanes.The high dissipation efficiency of PHCs was the synergistic result of root accumulation and microbial biodegradation.The key microbes involved in PHC dissipation were revealed,with the dominant phylum Proteobacteria and genus Salinimicrobium.The alterations in microbial diversity and abundance were closely associated with root exudation and PHC exposure.Significant differences in enzyme activities,an indicator of soil health and fertility,were observed between the rhizospheric and non-rhizospheric soils,which was attributed to root exudation.This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soils and serves as a valuable scientific reference for the phytoremediation of such soils.展开更多
The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insuffic...The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insufficient Cu^(+)/Cu^(0)active sites lead to their limited selectivity and stability for C_(2+)production.Herein,we embedded copper oxide(CuO_(x))particles into porous nitrogen-doped carbon nanofibers(CuO_(x)@PCNF)by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu_(2)O particles.The porous nitrogendoped carbon nanofibers protected and dispersed Cu^(+)species,and its micro porous structure enhanced the interaction between CuO_(x)and reactants during eCO_(2)RR.The obtained CuO_(x)@PCNF created more effective and stable Cu^(+)/Cu^(0)active sites.It showed a high Faradaic efficiency of 62.5%for C_(2+)products in Hcell,which was 2 times higher than that of bare CuO_(x)(~31.1%).Furthermore,it achieved a maximum Faradaic efficiency of 80.7%for C_(2+)products in flow cell.In situ characterization and density functional theory(DFT)calculation confirmed that the N-doped carbon layer protected Cu^(+)from electrochemical reduction and lowered the energy barrier for the dimerization of^(*)CO.Stable and exposed Cu^(+)/Cu^(0)active sites enhanced the enrichment of^(*)CO and promoted the C-C coupling reaction on the catalyst surface,which facilitated the formation of C_(2+)products.展开更多
In sulfidic anoxic environments,iron sulfides are widespread solid phases that play an important role in the arsenic(As)biogeochemical cycle.This work investigated the transformation process of FeS-As coprecipitates,t...In sulfidic anoxic environments,iron sulfides are widespread solid phases that play an important role in the arsenic(As)biogeochemical cycle.This work investigated the transformation process of FeS-As coprecipitates,the concurrent behavior,and the speciation of associated As under anoxic conditions.The results showed that FeS-As coprecipitates could convert to greigite and pyrite.The transformation degree of the produced solid phases was dependent upon the pH conditions and initial As species.These results showed that the As mobilization was closely associated with the solid phase transformation.The solid phase transformationwent from disordered mackinawite to crystallinemackinawite,then greigite and finally pyrite.The As in the coprecipitates underwent a process of release,fixation,and release again.Both reduction of As(Ⅴ)and oxidation of As(Ⅲ)were observed in the aqueous and solid phases during reactions.Our study may have important implications for further understanding of As behavior and Fe/S cycling thatmay occur under an anoxic environment more comprehensively.展开更多
Sediment quality in global estuaries was reported by assessing the degree of anthropogenic input and the corresponding ecological risks.This research intended to categorize the quantities of marine pollution at the mo...Sediment quality in global estuaries was reported by assessing the degree of anthropogenic input and the corresponding ecological risks.This research intended to categorize the quantities of marine pollution at the mouth of the Chanthaburi River,on the Eastern Gulf of Thailand,by examining the interactions amongst the heavy metals(Pb,Cd,Cu,Zn)and microplastics(MPs)in surface marine sediments.Marine pollution severity was classified using the Geo-accumulation Index(I_(geo)),Sediment Enrichment Factor(SEF),and Pollution Load Index(PLI).Spatial distribution of pollutants and geostatistical covariance were examined via Geographic Information System(GIS)and Principal Component Analysis(PCA).The average concentrations determined in sediment samples were as follows:Pb,0.369±0.022 ppm;Cd,0.0042±0.0004 ppm;Cu,5.424±0.007 ppm;Zn,33.756±0.182 ppm;and microplastics,1.36±0.06 particles/g.All metal levels were below the WASV,CCV,and TRV reference thresholds.I_(geo) and SEF indicated that Zn was moderately accumulated with minor enrichment,while other metals were unpolluted.PCA explained 90.85%of the variance,mainly reflecting Zn accumulation in downstream sites.We also found an inconspicuous correlation between heavy metals and MPs,which may be caused by distinct sources,physicochemical properties,and potential biological synergistic effects that remain unclear.A key originality of this study lies in the integration of GIS-based spatial interpolation with the PLI data to visualize and distinguish site-specific accumulation zones.The study did not assess biological uptake or biomarkers,limiting insight into actual bioavailability and toxicity to marine species.These findings provide spatially explicit evidence for targeted estuarine management and highlight the need for future studies on bioavailability and ecological risks.展开更多
Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contributi...Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contribution from potential non-biomass burning sources,such as cooking.To address this,we examined the dynamic variation and sources of levoglucosan using a chemical ionization mass spectrometer and other advanced instruments during Beijing’s summer of 2021.The average mass concentration of levoglucosan and its isomer(C_(6)H_(10)O_(5))was 0.025±0.014μg/m^(3),constituting 0.55%±0.32%of total organic carbon(OC)in this campaign.Despite cooking emissions contributing significantly to the organic aerosol(OA,20%),levoglucosan and its isomers correlated more strongly with biomass-burning related tracers(R>0.6),black carbon(R=0.72)and less so with cooking-related sources(R=0.3).This indicates that levoglucosan is primarily dominated by biomass-burning emissions rather than cooking in Beijing’s urban areas during summertime.The diurnal variation of levoglucosan concentrations highlighted the importance of daytime and nocturnal biomass burning emissions during polluted periods in Beijing.Using levoglucosan as a tracer to quantify the biomass burning OC(BBOC),we found good agreement on the time series of BBOC between the tracermethod and other independent source apportionmentmethod.This reaffirms the reliability of levoglucosan as a biomass burning tracer.Biomass burning contributed an average of 7%-8%to OC,highlighting its significant impact on Beijing’s summer air quality.Our study enhances understanding of biomass burning influences on ambient aerosol in typical urban areas.展开更多
Oxygenated volatile organic compounds(OVOCs) are important precursors and products of atmospheric secondary pollution. The sources of OVOCs, however, are still quite uncertain,especially in the atmosphere with much po...Oxygenated volatile organic compounds(OVOCs) are important precursors and products of atmospheric secondary pollution. The sources of OVOCs, however, are still quite uncertain,especially in the atmosphere with much pollution in China. To study the sources of OVOCs in rural atmospheres, a proton transfer reaction mass spectrometry(PTR-MS) was deployed at a northern rural site(WD) and a southern rural site(YMK) in China during the summer of 2014 and 2016, respectively. The continuous observation showed that the mean concentration of TVOCs(totally 17 VOCs) measured at WD(52.4 ppbv) was far higher than that at YMK(11.1 ppbv), and the OVOCs were the most abundant at both the two sites. The diurnal variations showed that local sources of OVOCs were still prominent at WD, while regional transport influenced YMK much. The photochemical age-based parameterization method was then used to quantitatively apportion the sources of ambient OVOCs. The anthropogenic primary sources at WD and YMK contributed less(2%–16%) to each OVOC species. At both the sites, the atmospheric background had a dominant contribution(～ 50%) to acetone and formic acid, while the anthropogenic secondary formation was the main source(～ 40%) of methanol and MEK. For acetaldehyde and acetic acid, the biogenic sources were their largest source(～ 40%) at WD, while the background(39%) and anthropogenic secondary formation(42%) were their largest sources at YMK, respectively. This study reveals the complexity of sources of OVOCs in China, which urgently needs explored further.展开更多
Oxygenated volatile organic compounds(OVOCs) are key intermediates in the atmospheric photooxidation process. To further study the primary and secondary sources of OVOCs,their ambient levels were monitored using a pro...Oxygenated volatile organic compounds(OVOCs) are key intermediates in the atmospheric photooxidation process. To further study the primary and secondary sources of OVOCs,their ambient levels were monitored using a proton-transfer reaction mass spectrometer(PTR-MS) at an urban site in the Pearl River Delta of China. Continuous monitoring campaigns were conducted in the spring, summer, fall, and winter of 2016. Among the six types of OVOC species, the mean concentrations of methanol were the highest in each season(up to 13–20 ppbv), followed by those of acetone, acetaldehyde and acetic acid(approximately 2–4 ppbv), while those of formic acid and methyl ethyl ketone(MEK) were the lowest(approximately 1–2 ppbv). As observed from a diurnal variation chart, the OVOCs observed in Shenzhen may have been affected by numerous factors such as their primary and secondary sources and photochemical consumption. The photochemical age-based parameterization method was used to apportion the sources of ambient OVOCs. Methanol had significant anthropogenic primary sources but negligible anthropogenic secondary sources during all of the seasons. Acetone, MEK and acetic acid were mostly attributed to anthropogenic primary sources during each season with smaller contributions from anthropogenic secondary sources. Acetaldehyde had similar contributions from both anthropogenic secondary and anthropogenic primary sources throughout the year.Meanwhile, anthropogenic primary sources contributed the most to formic acid.展开更多
All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciati...All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C （Cmic）/organic C （Corg） ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient.展开更多
Copper-based catalysts for CO2 hydrogenation to methanol are supported on ZrO2 and CeO2,respectively.Reaction results at 3.0 MPa and temperatures between 200 and 300°C reveal that Cu catalysts supported on ZrO2 a...Copper-based catalysts for CO2 hydrogenation to methanol are supported on ZrO2 and CeO2,respectively.Reaction results at 3.0 MPa and temperatures between 200 and 300°C reveal that Cu catalysts supported on ZrO2 and CeO2 exhibit better activity and selectivity than pure Cu catalyst due to Cu-support(ZrO2 and CeO2)interaction.Combining the structural characterizations with in-situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS),Cu/CeO2 shows the higher methanol selectivity due to the formation of main carbonates intermediates,which are closely related with the oxygen vacancies over Cu/CeO2.In contrast,bicarbonate and carboxyl species are observed on Cu/ZrO2,which originates from the hydroxyl groups presented on catalyst surfaces.Difference in CO2 adsorption intermediates results in the distinct methanol selectivity over the two catalysts.展开更多
A rhizobox experiment with two phosphorus (P) treatments, zero-P (0 mg P kg-1) and plus-P (100 mg P kg-1) as Ca(H2PO4)2·H2O, was conducted to study the chemical and biochemical properties in the rhizosphere of tw...A rhizobox experiment with two phosphorus (P) treatments, zero-P (0 mg P kg-1) and plus-P (100 mg P kg-1) as Ca(H2PO4)2·H2O, was conducted to study the chemical and biochemical properties in the rhizosphere of two rice genotypes (cv. Zhongbu 51 and Pembe) different in P uptake ability and their relationship with the depletion of soil P fractions. Plant P uptake, pH, phosphatase activity, and soil P fractions in the rhizosphere were measured. Both total dry weight and total P uptake of Pembe were significantly (P < 0.05) higher than those of Zhongbu 51 in the zero-P and plus-P treatments. Significant depletions of resin-Pi, NaHCO3-Pi, NaHCO3-Po, and NaOH-Pi, where Pi stands for inorganic P and Po for organic P, were observed in the rhizosphere of both Zhongbu 51 and Pembe under both P treatments. Pembe showed a greater ability than Zhongbu 51 in depleting resin-Pi, NaHCO3-Pi, NaHCO3-Po, NaOH-Pi, and NaOH- Po in the rhizosphere. HCl-Pi and residual-P were not depleted in the rhizosphere of both genotypes, regardless of P treatments despite significant acidification in the rhizosphere of Pembe under zero-P treatment. Higher acid phosphatase (AcPME) activity and alkaline phosphatase (AlPME) activity were observed in the rhizosphere of both Zhongbu 51 and Pembe compared to the corresponding controls without plant. AcPME activity was negatively (P < 0.01) correlated to NaHCO3-Po concentration in the rhizosphere of both Zhongbu 51 and Pembe, suggesting that AcPME was associated with the mineralization of soil organic P.展开更多
基金supported by Natural Science Foundation of Xiamen,China(No.3502Z20227232)the STS Project of Fujian-CAS(No.2023T3018)Bureau of International Cooperation,Chinese Academy of Sciences(No.322GJHZ2022035MI).
文摘Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key factors in anammox bacteria enrichment.This study investigated the mechanisms driving anammox bacteria enrichment in lab-scale simulated CWs treating high-nitrogen wastewater,focusing on bacterial community re-sponses across wetland layers with various strategies,including continuous up-flow influent,nitrogen loading increase,effluent recirculation,intermittent influent,and anammox bacteria inoculation.Results showed that total relative and absolute abundances of anammox bacteria ranged from 0.77%to 12.50%and from 0.13 to 6.46×10^(7) copies/g,respectively.Dissolved oxygen and pH had significant positive correlations with the absolute abundance of anammox bacteria,while organic matter and nitrate negatively impacted their relative abundance.Permutational multivariate analysis of variance indicated that spatial heterogeneity explained more variation in anammox bacteria abundance(43.44%)compared to operational strategies(8.58%).In terms of microbial interactions,60 dominant species exhibited potential correlations with anammox bacteria,comprising 170 interactions(105 positive and 65 negative),which suggested that anammox bacteria generally foster cooperative relationships with dominant bacteria.Notably,significant interspecies interactions were observed between Candidatus Kuenenia(dominant anammox bacteria in CWs)and species within the genera Chitinivibrio-nia and Anaerolineaceae,suggesting that microbial interactions primarily manifest as indirect facilitative effects rather than direct mutualistic relationships.Given that the Normalized Stochasticity Ratio in CWs were<50%,this study inferred that environmental gradients have greater influence on anammox bacteria than microbial interactions.
基金supported by the National Natural Science Foundation of China(Nos.21976045 and 22076112)the CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation(No.2020KFJJ03).
文摘Obtaining the sulfonamides(SAs)concentrations in the water body and sediment bulk was a prerequisite to reveal their transport and partitioning behavior in sediment-water environments and accurately assess their ecological risk.In the present study,the influences of multifactor interactions on the performance of o-DGTs with XAD-18 binding gels were analyzed by central combination experiments and response surfaces analysis,in which the target compounds were 9 SAs.The results indicated that dissolved organic matter(DOM),pH,and suspended particulate matter(SS)had significant effects on the o-DGT sampling,whereas this o-DGT was independent of the ionic strength(IS).Concentning the composite influence of the four factors,the interaction between DOM and SS posed the most significant effect on all 9 SAs compounds.Subsequently,an o-DGT and DIFSmodel was applied to explore the SAs migration between the water-sediments interface.The difference between desorption rate(k_(b))and adsorption rates(k_(f))values suggested that the kinetics of SAs was dominated by adsorption.Moreover,the short-term sediment-water partitioning of SAs was clarified on the basis of distribution coefficient(K_(dl))for the labile SAs,among which the sulfadiazine(SDZ)had the largest labile pool.The ability of sediments to release SAs to the liquid phase as a sink was determined by response time(T_(c)).Among the 9 SAs,the longterm release of soseulfamethoxypyridazine(SMP)from the solid phase of sediments would have a potential risk to the aquatic environment,to which more attention should be paid in the future.
基金funding from the Environmental Science Program for Academic Excellence and Community Research for Fiscal Year 2024,a financial resource of the Environmental Science and Technology Program,Faculty of Science,Buriram Rajabhat University.Additionally,Buriram Rajabhat University provided a publication budget.
文摘Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films from fruits and vegetables,using alginate as a binding agent.Using a completely randomized design,seven experimental sets were prepared with carrots,Kimju guava,and Namwa banana peel fibers as the primary materials and alginate as the secondary material at three levels:1.2,1.8,and 2.4 by weight.The solution technique was employed to create the samples.Upon testing mechanical and physical properties,experimental set 3,consisting of 60%guava and 1.8%alginate,emerged as the optimal ratio.This combination exhibited favorable physical properties,including a thickness of 0.26±0.02 mm,meeting the standards for food packaging films.Additionally,the tensile strength was 0.50±0.01 N/m²,and the elongation at break was 55.60±0.44%.Regarding chemical properties,the moisture content of 5.64±0.03%fell within the acceptable range for dried food.Furthermore,a 30-day soil burial test revealed that the sample from experimental set 3 exhibited the highest degradation rate.In conclusion,these findings suggest that guava can be a promising raw material for producing biodegradable plastics suitable for packaging applications.
基金supported by Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515110824 and 2025A1515011839)Shenzhen Science and Technology Program(No.RCBS20231211090638066).
文摘Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-ments in karst hydrology,significant gaps remain in long-term trends,underlying processes,and quantitative effects of environmental changes.This is especially true in areas like the Wujiang River(WJ)in China,where human activities such as reservoir construction and land use/cover changes have accelerated hydrochemical changes.We combined recent and historical monitoring data to provide a detailed analysis of the spatial and temporal characteristics,evolution,and controlling factors of major ions in WJ.These findings are important for local water management and contribute to global efforts to manage similar karst systems facing human-induced pressures.Our research shows clear seasonal differences in solute concentrations,with higher levels during the dry season.WJ’s water is rich in calcium,with Ca-HCO_(3) ion pairs being the most common.Reservoir monitor-ing stations show much higher levels of NO_(3)^(−)and SO_(4)^(2−)compared to river-type stations,likely due to longer hydraulic retention time and increased acid deposition.The study confirms the significant role of pH and water temperature in rock weathering processes.Land use/cover changes were identified as the primary drivers of solute variations(46.37%),followed by lithology(13.92%)and temperature(8.35%).Over the past two decades,in-tense carbonate weathering has been observed,especially during wet seasons.Among karstic provinces,Guizhou Province stands out with the highest ion concentrations,indicative of its extensive karst coverage and heightened weathering processes.
基金the financial support from the National Natural Science Foundation of China(52172110,52472231,52311530113)Shanghai"Science and Technology Innovation Action Plan"intergovernmental international science and technology cooperation project(23520710600)+1 种基金Science and Technology Commission of Shanghai Municipality(22DZ1205600)the Central Guidance on Science and Technology Development Fund of Zhejiang Province(2024ZY01011)。
文摘Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.
基金Project supported by the National Key Basic Research Support Foundation of China (No. G1998040800).
文摘Pedogenic carbonates, found extensively in arid and semiarid regions, are important in revealing regional climatic and environmental changes as well as the carbon cycle. In addition, stable carbon and oxygen isotopic compositions of pedogenic carbonates have been used to rebuild paleoecology (biomass and vegetation) and to estimate paleotemperature and paleoprecipitation during past geological time. By utilizing the stable carbon and oxygen isotopic compositions (δ13C and (δ18O) of secondary nodules in Ustic Vertisols, this study looked into the climatic and environmental changes in the dry valleys of the Yuanmou Basin, Yunnan Province, in southwestern China. The results showed that during the early Holocene, a warm-humid or hot-humid climate existed in the Yuanmou Basin, but since then fluctuations in climate have occurred, with a dry climate prevailing. A highly significant correlation (r = 0.92, n = 9) between δ13C and δ18O values of carbonates illustrated that there had been a continual shifting between cold-humid and warm-dry climates in southwestern China including the Yuanmou Basin since the early Holocene.
文摘The bottom ash and fly ash from the co-combustion of wood residues and peat at a bubbling fluidised bed boiler（296 MW） contained only quartz（SiO_2）, microcline（KAl Si_3O_8） and albite（NaAlSi_3O_8）. Thus, X-ray powder diffraction（XRD） was not useful for clarifying the difference in the release of associated heavy metals from ash matrices. In order to assess the release of heavy metals from ashes under changing environmental conditions, they were sequentially extracted and fractionated by the BCR-procedure into acid soluble/exchangeable（CH_3COOH）, reducible（NH_2OH-HCl） and oxidizable（H_2O_2/CH_3COONH_4） phases. The CH_3 COOH extractable fraction in conjunction with the total heavy metals concentrations were used to calculate the risk assessment code values for heavy metals leaching from the ash matrix. The leaching studies indicate that the heavy metals in the bottom ash and fly ash are bound to different fractions with different strengths. From the environmental and utilization perspectives, heavy metals in ashes posed different levels of environmental contamination risk. Only As in the bottom ash posed a very high risk. High risk metals were Cd in the bottom ash as well as As, Cd and Se in the fly ash.
基金Project(2011BAJ01B05) supported by the National Science and Technology Pillar Program during the Twelfth Five-year Plan Period of China
文摘With rapid economy growth,building energy consumption in China has been gradually increased.The energy consumption and indoor environmental quality of 51 office buildings in Hainan Province,a hot and humid area,were studied through collection of verified data in site visits and field tests.The result revealed that,electricity accounted for 99.79% of the total energy consumption,natural gas 0.17%,and diesel 0.04%.The air conditioning dominated the energy use with a share of 43.18%,equipment in the particular areas 26.90%,equipment in the office rooms 11.95%,lighting system 8.67%,general service system 7.57%,and miscellaneous items 1.73%.Statistical method including six indicators obtained the energy consumption benchmark with upper limit of 98.31 kW-h/m2 and lower limit of 55.26 kW-h/m2.According to ASHRAE standard(comfortable standard) and GB/T 18883-2002(acceptable standard),the indoor environmental quality of 51 sampled office buildings was classified into three ranks:good,normal and bad.With benchmark of building energy consumption combined with indoor environmental quality,it was found that only 3.92% of sampled buildings can be identified as the best performance buildings with low energy consumption and advanced indoor environmental quality,and the buildings classified into normal level accounted for the maximum ratio.
文摘Human exposure to toxic metals is on the increase especially in the developing world;this is compounded by the almost unavoidable application of the metals domestically and industrially and their implication in several genetic defects, aging and some chronic illnesses including Autism Spectrum Disorders (ASD). This study investigated the concentration of toxic metals (Pb and V) and micro-essential elements (Cu and Se) in children with ASD and controls in Nigeria towards establishing their possible associations with the aetiopathogenesis of ASD. Eight children clinically diagnosed by Paediatric Neurologist and Child Psychiatrist for ASD using DMS-IV and fifteen apparently healthy children (age range 2 - 12 years) were recruited as cases and controls respectively. Plasma levels of Pb, V, Cu and Se were analyzed using Induction ICP-MS. Results were analyzed using students t-test. The mean plasma lead and vanadium levels were (7.92 ± 1.30 μg/dl;1.07 ± 0.22 μg/dl) and (6.83 ± 0.72 μg/dl;2.59 ± 0.48 μg/dl) in children with ASD and in controls respectively. The result showed that blood lead level in ASD was slightly increased but not significant when compared with control (p < 0.433). On the other hand, plasma vanadium concentration in ASD was significantly reduced (1.07 ± 0.22 μg/dl) when compared with control (2.59 ± 0.48 μg/dl) (P < 0.038). Mean plasma copper was similar in all participants (1.98 ± 0.13, 2.23 ± 0.12) but selenium concentrations were significantly reduced (0.37 ± 0.05 mg/L;0.57 ± 0.02 mg/L) in ASD relative to controls respectively. Given the physiological functions of vanadium and selenium, the observed reduced levels of the two elements in children with ASD may account for the speech and other neurological dysfunctions of the brain in ASD.
基金supported by National Nature Science Foundation of China(22105118)Nature Science Foundation of Shandong Provinces(ZR2021QB095)China Postdoctoral Science Foundation(2020TQ0183 and 2021M701979).
文摘Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kinetics still require improvement.Encouraged by the excellent electrochemical performance of titanium-based anode materials,here,we present a novel titanium vanadate@carbon(TVO@C)material as anode for SIBs.Our TVO@C material is synthesized via a facile coprecipitation method,with the following annealing process in an acetylene atomosphere.The opened ion channel and the oxygen vacancies within TVO@C facilitate the diffusion of Na^(+) ions,reducing their diffusion barrier.Thus,an ultrahigh rate of 100 A g^(-1)and long life of 10,000 cycles have been achieved.Furthermore,the TVO@C electrode exhibits stable performance,not only at room temperature,but also at temperatures as low as 20 C.The TVO@CjjNa_(3)V_(2)(PO_(4))_(3)@C full cells have also achieved stable discharge/charge for 500 cycles.It is believed that this strategy provides new insight into the development of advanced electrodes and provides a new opportunity for constructing novel high rate electrodes.
基金financially supported by the National Natural Science Foundation of China(Nos.22176025 and 22136007)the National Key Research and Development Program of China(No.2022YFC3701404)the Petro China Innovation Foundation(No.D2019-5007-0502)。
文摘Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated.This work concentrated on the potential evolution of soil microbiomes and their effects on PHC dissipation within the Suaeda salsa(L.)Pall.planting system in a pot experiment.Two representative compounds,polycyclic aromatic hydrocarbons(PAHs)and n-alkanes,were used as target PHCs.The findings revealed a significant efficiency in the dissipation of PHCs in soil with Suaeda salsa cultivation,particularly with respect to n-alkanes.The high dissipation efficiency of PHCs was the synergistic result of root accumulation and microbial biodegradation.The key microbes involved in PHC dissipation were revealed,with the dominant phylum Proteobacteria and genus Salinimicrobium.The alterations in microbial diversity and abundance were closely associated with root exudation and PHC exposure.Significant differences in enzyme activities,an indicator of soil health and fertility,were observed between the rhizospheric and non-rhizospheric soils,which was attributed to root exudation.This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soils and serves as a valuable scientific reference for the phytoremediation of such soils.
基金supported by the National Natural Science Foundation of China(22222601 and 22076019)the Fundamental Research Funds for the Central Universities(DUT23LAB611).
文摘The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insufficient Cu^(+)/Cu^(0)active sites lead to their limited selectivity and stability for C_(2+)production.Herein,we embedded copper oxide(CuO_(x))particles into porous nitrogen-doped carbon nanofibers(CuO_(x)@PCNF)by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu_(2)O particles.The porous nitrogendoped carbon nanofibers protected and dispersed Cu^(+)species,and its micro porous structure enhanced the interaction between CuO_(x)and reactants during eCO_(2)RR.The obtained CuO_(x)@PCNF created more effective and stable Cu^(+)/Cu^(0)active sites.It showed a high Faradaic efficiency of 62.5%for C_(2+)products in Hcell,which was 2 times higher than that of bare CuO_(x)(~31.1%).Furthermore,it achieved a maximum Faradaic efficiency of 80.7%for C_(2+)products in flow cell.In situ characterization and density functional theory(DFT)calculation confirmed that the N-doped carbon layer protected Cu^(+)from electrochemical reduction and lowered the energy barrier for the dimerization of^(*)CO.Stable and exposed Cu^(+)/Cu^(0)active sites enhanced the enrichment of^(*)CO and promoted the C-C coupling reaction on the catalyst surface,which facilitated the formation of C_(2+)products.
基金supported by the National Key Research and Development Program of China(No.2022YFC3701301)the National Natural Science Foundation of China(Nos.42173063 and 42377251)+1 种基金the Youth Innovation Promotion Association CAS(No.2020200)the Fundamental Research Funds for the Central Universities.
文摘In sulfidic anoxic environments,iron sulfides are widespread solid phases that play an important role in the arsenic(As)biogeochemical cycle.This work investigated the transformation process of FeS-As coprecipitates,the concurrent behavior,and the speciation of associated As under anoxic conditions.The results showed that FeS-As coprecipitates could convert to greigite and pyrite.The transformation degree of the produced solid phases was dependent upon the pH conditions and initial As species.These results showed that the As mobilization was closely associated with the solid phase transformation.The solid phase transformationwent from disordered mackinawite to crystallinemackinawite,then greigite and finally pyrite.The As in the coprecipitates underwent a process of release,fixation,and release again.Both reduction of As(Ⅴ)and oxidation of As(Ⅲ)were observed in the aqueous and solid phases during reactions.Our study may have important implications for further understanding of As behavior and Fe/S cycling thatmay occur under an anoxic environment more comprehensively.
基金supported by the Research Fund of Rambhai Barni Rajabhat University(RBRU,Contract No.2221/2023),Thailand.
文摘Sediment quality in global estuaries was reported by assessing the degree of anthropogenic input and the corresponding ecological risks.This research intended to categorize the quantities of marine pollution at the mouth of the Chanthaburi River,on the Eastern Gulf of Thailand,by examining the interactions amongst the heavy metals(Pb,Cd,Cu,Zn)and microplastics(MPs)in surface marine sediments.Marine pollution severity was classified using the Geo-accumulation Index(I_(geo)),Sediment Enrichment Factor(SEF),and Pollution Load Index(PLI).Spatial distribution of pollutants and geostatistical covariance were examined via Geographic Information System(GIS)and Principal Component Analysis(PCA).The average concentrations determined in sediment samples were as follows:Pb,0.369±0.022 ppm;Cd,0.0042±0.0004 ppm;Cu,5.424±0.007 ppm;Zn,33.756±0.182 ppm;and microplastics,1.36±0.06 particles/g.All metal levels were below the WASV,CCV,and TRV reference thresholds.I_(geo) and SEF indicated that Zn was moderately accumulated with minor enrichment,while other metals were unpolluted.PCA explained 90.85%of the variance,mainly reflecting Zn accumulation in downstream sites.We also found an inconspicuous correlation between heavy metals and MPs,which may be caused by distinct sources,physicochemical properties,and potential biological synergistic effects that remain unclear.A key originality of this study lies in the integration of GIS-based spatial interpolation with the PLI data to visualize and distinguish site-specific accumulation zones.The study did not assess biological uptake or biomarkers,limiting insight into actual bioavailability and toxicity to marine species.These findings provide spatially explicit evidence for targeted estuarine management and highlight the need for future studies on bioavailability and ecological risks.
基金supported by the National Key R&D Program of China(Nos.2022YFC3701000 and 2021YFA1601800)the National Natural Science Foundation of China(Nos.42230701 and 42375105)+1 种基金the Foundation for Program of Science and Technology Research(No.2024A1515011937)Guangdong Foundation for Program of Science and Technology Research(No.2023B1212060049).
文摘Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contribution from potential non-biomass burning sources,such as cooking.To address this,we examined the dynamic variation and sources of levoglucosan using a chemical ionization mass spectrometer and other advanced instruments during Beijing’s summer of 2021.The average mass concentration of levoglucosan and its isomer(C_(6)H_(10)O_(5))was 0.025±0.014μg/m^(3),constituting 0.55%±0.32%of total organic carbon(OC)in this campaign.Despite cooking emissions contributing significantly to the organic aerosol(OA,20%),levoglucosan and its isomers correlated more strongly with biomass-burning related tracers(R>0.6),black carbon(R=0.72)and less so with cooking-related sources(R=0.3).This indicates that levoglucosan is primarily dominated by biomass-burning emissions rather than cooking in Beijing’s urban areas during summertime.The diurnal variation of levoglucosan concentrations highlighted the importance of daytime and nocturnal biomass burning emissions during polluted periods in Beijing.Using levoglucosan as a tracer to quantify the biomass burning OC(BBOC),we found good agreement on the time series of BBOC between the tracermethod and other independent source apportionmentmethod.This reaffirms the reliability of levoglucosan as a biomass burning tracer.Biomass burning contributed an average of 7%-8%to OC,highlighting its significant impact on Beijing’s summer air quality.Our study enhances understanding of biomass burning influences on ambient aerosol in typical urban areas.
基金supported by the Ministry of Science and Technology of China,China(No.2017YFC0210004)the National Natural Science Foundation of China,China(No.91544215)the Science and Technology Plan of Shenzhen Municipality(No.JCYJ20170412150626172)
文摘Oxygenated volatile organic compounds(OVOCs) are important precursors and products of atmospheric secondary pollution. The sources of OVOCs, however, are still quite uncertain,especially in the atmosphere with much pollution in China. To study the sources of OVOCs in rural atmospheres, a proton transfer reaction mass spectrometry(PTR-MS) was deployed at a northern rural site(WD) and a southern rural site(YMK) in China during the summer of 2014 and 2016, respectively. The continuous observation showed that the mean concentration of TVOCs(totally 17 VOCs) measured at WD(52.4 ppbv) was far higher than that at YMK(11.1 ppbv), and the OVOCs were the most abundant at both the two sites. The diurnal variations showed that local sources of OVOCs were still prominent at WD, while regional transport influenced YMK much. The photochemical age-based parameterization method was then used to quantitatively apportion the sources of ambient OVOCs. The anthropogenic primary sources at WD and YMK contributed less(2%–16%) to each OVOC species. At both the sites, the atmospheric background had a dominant contribution(～ 50%) to acetone and formic acid, while the anthropogenic secondary formation was the main source(～ 40%) of methanol and MEK. For acetaldehyde and acetic acid, the biogenic sources were their largest source(～ 40%) at WD, while the background(39%) and anthropogenic secondary formation(42%) were their largest sources at YMK, respectively. This study reveals the complexity of sources of OVOCs in China, which urgently needs explored further.
基金supported by the Ministry of Science and Technology of China (Nos.2017YFC0210004,2014BAC21B01)the Science and Technology Plan of Shenzhen Municipality (Nos.JCYJ20170412150626172,JCYJ20160122105855253)
文摘Oxygenated volatile organic compounds(OVOCs) are key intermediates in the atmospheric photooxidation process. To further study the primary and secondary sources of OVOCs,their ambient levels were monitored using a proton-transfer reaction mass spectrometer(PTR-MS) at an urban site in the Pearl River Delta of China. Continuous monitoring campaigns were conducted in the spring, summer, fall, and winter of 2016. Among the six types of OVOC species, the mean concentrations of methanol were the highest in each season(up to 13–20 ppbv), followed by those of acetone, acetaldehyde and acetic acid(approximately 2–4 ppbv), while those of formic acid and methyl ethyl ketone(MEK) were the lowest(approximately 1–2 ppbv). As observed from a diurnal variation chart, the OVOCs observed in Shenzhen may have been affected by numerous factors such as their primary and secondary sources and photochemical consumption. The photochemical age-based parameterization method was used to apportion the sources of ambient OVOCs. Methanol had significant anthropogenic primary sources but negligible anthropogenic secondary sources during all of the seasons. Acetone, MEK and acetic acid were mostly attributed to anthropogenic primary sources during each season with smaller contributions from anthropogenic secondary sources. Acetaldehyde had similar contributions from both anthropogenic secondary and anthropogenic primary sources throughout the year.Meanwhile, anthropogenic primary sources contributed the most to formic acid.
基金Project supported by the National Natural Science Foundation of Chi-na (No. 40432004, 40601086) the Natural Science Foundationof Zhejiang Province (No. Y504109).
文摘All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C （Cmic）/organic C （Corg） ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient.
基金financially supported by the National Natural Science Foundation of China (21577014, 21876019, 21825203, 21688102)Programme of Introducing Talents of Discipline to Universities (B13012)the fund of the State Key Laboratory of Catalysis in DICP (Y401010502)
文摘Copper-based catalysts for CO2 hydrogenation to methanol are supported on ZrO2 and CeO2,respectively.Reaction results at 3.0 MPa and temperatures between 200 and 300°C reveal that Cu catalysts supported on ZrO2 and CeO2 exhibit better activity and selectivity than pure Cu catalyst due to Cu-support(ZrO2 and CeO2)interaction.Combining the structural characterizations with in-situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS),Cu/CeO2 shows the higher methanol selectivity due to the formation of main carbonates intermediates,which are closely related with the oxygen vacancies over Cu/CeO2.In contrast,bicarbonate and carboxyl species are observed on Cu/ZrO2,which originates from the hydroxyl groups presented on catalyst surfaces.Difference in CO2 adsorption intermediates results in the distinct methanol selectivity over the two catalysts.
基金the National High Technology Research and Development Program (863 Program) of China(No.2001AA241025-1).
文摘A rhizobox experiment with two phosphorus (P) treatments, zero-P (0 mg P kg-1) and plus-P (100 mg P kg-1) as Ca(H2PO4)2·H2O, was conducted to study the chemical and biochemical properties in the rhizosphere of two rice genotypes (cv. Zhongbu 51 and Pembe) different in P uptake ability and their relationship with the depletion of soil P fractions. Plant P uptake, pH, phosphatase activity, and soil P fractions in the rhizosphere were measured. Both total dry weight and total P uptake of Pembe were significantly (P < 0.05) higher than those of Zhongbu 51 in the zero-P and plus-P treatments. Significant depletions of resin-Pi, NaHCO3-Pi, NaHCO3-Po, and NaOH-Pi, where Pi stands for inorganic P and Po for organic P, were observed in the rhizosphere of both Zhongbu 51 and Pembe under both P treatments. Pembe showed a greater ability than Zhongbu 51 in depleting resin-Pi, NaHCO3-Pi, NaHCO3-Po, NaOH-Pi, and NaOH- Po in the rhizosphere. HCl-Pi and residual-P were not depleted in the rhizosphere of both genotypes, regardless of P treatments despite significant acidification in the rhizosphere of Pembe under zero-P treatment. Higher acid phosphatase (AcPME) activity and alkaline phosphatase (AlPME) activity were observed in the rhizosphere of both Zhongbu 51 and Pembe compared to the corresponding controls without plant. AcPME activity was negatively (P < 0.01) correlated to NaHCO3-Po concentration in the rhizosphere of both Zhongbu 51 and Pembe, suggesting that AcPME was associated with the mineralization of soil organic P.
