The Co_(3)O_(4)nanoparticles,dominated by a catalytically active(110)lattice plane,were synthesized as a low-temperature NO_(x) adsorbent to control the cold start emissions from vehicles.These nanoparticles boast a s...The Co_(3)O_(4)nanoparticles,dominated by a catalytically active(110)lattice plane,were synthesized as a low-temperature NO_(x) adsorbent to control the cold start emissions from vehicles.These nanoparticles boast a substantial quantity of active chemisorbed oxygen and lattice oxygen,which exhibited a NO_(x) uptake capacity commensurate with Pd/SSZ-13 at 100℃.The primary NO_(x) release temperature falls within a temperature range of 200-350℃,making it perfectly suitable for diesel engines.The characterization results demonstrate that chemisorbed oxygen facilitate nitro/nitrites intermediates formation,contributing to the NO_(x) storage at 100℃,while the nitrites begin to decompose within the 150-200℃range.Fortunately,lattice oxygen likely becomes involved in the activation of nitrites into more stable nitrate within this particular temperature range.The concurrent processes of nitrites decomposition and its conversion to nitrates results in a minimal NO_(x) release between the temperatures of 150-200℃.The nitrate formed via lattice oxygen mainly induces the NO_(x) to be released as NO_(2) within a temperature range of 200-350℃,which is advantageous in enhancing the NO_(x) activity of downstream NH_(3)-SCR catalysts,by boosting the fast SCR reaction pathway.Thanks to its low cost,considerable NO_(x) absorption capacity,and optimal release temperature,Co_(3)O_(4)demonstrates potential as an effective material for passive NO_(x) adsorber applications.展开更多
Adansonia digitata L.(Malvaceae) is commonly known as baobab tree native to Africa.Baobab is a multi-purpose tree which offers protection and provides food,clothing and medicine as well as raw material for many useful...Adansonia digitata L.(Malvaceae) is commonly known as baobab tree native to Africa.Baobab is a multi-purpose tree which offers protection and provides food,clothing and medicine as well as raw material for many useful items.The fruit pulp,seeds,leaves,flowers.roots,and bark of baobab are edible and they have been studied by scientists for their useful properties.The fruit pulp have very high vitamin C.calcium,phosphorus,carbohydrates,fibers,potassium,proteins and lipids content,which can be used in seasoning as an appetizer and also make juices.Seeds contain appreciable quantities of phosphorus,magnesium,zinc,sodium,iron,manganese,whereas they have high levels of lysine,thiamine,calcium and iron.Baobab has numerous biological properties including antimicrobial,anti-malarial,diarrhoea,anaemia,asthma,antiviral,anti-oxidant and anti-inflammatory activities amongst others.Phytochemical investigation revealed the presence of flavonoids.phytosterols.amino acids,fatty acids,vitamins and minerals.The review summarizes the information on various aspects of traditional information,taxonomic description,medicinal properties and importantly nutritional value.展开更多
In this work,the characterizations of Cu-SSZ-13 after hydrothermal aging(HTA)and thermal aging(TA)at different temperatures(750,800,and 850°C)are compared,and the differences between those two serious aged sample...In this work,the characterizations of Cu-SSZ-13 after hydrothermal aging(HTA)and thermal aging(TA)at different temperatures(750,800,and 850°C)are compared,and the differences between those two serious aged samples are analyzed.With this data,the effect of steam on catalysts deactivation during hydrothermal aging is analyzed.The TA at 750 and 800°C causes the dealumination and the agglomeration of Cu^(2+)ions to Cu O,resulting in the activity loss of Cu-SSZ-13.The presence of steam upon HTA at750 and 800°C aggravates the catalyst deactivation by increasing the Al detachment and the Cu^(2+)agglomeration.The structure and cupric state are almost the same in the Cu-SSZ-13 after TA and HTA at 850°C,respectively,indicating that the steam has little influence on the deactivation.The formation of CuAl_(2)O_(4) spinel is the primary reason for the deactivation after both HTA and TA at 850°C,probably attributed to the strong interaction between Cu^(2+)ions and framework Al sites at high temperatures.展开更多
In this study,ultrasonic field was applied during potassium hydroxide(KOH) pretreatment of wheat straw(WS).Three concentrations of KOH(2%,4%,and 6%) were tested during pretreatment.The results showed that there was a ...In this study,ultrasonic field was applied during potassium hydroxide(KOH) pretreatment of wheat straw(WS).Three concentrations of KOH(2%,4%,and 6%) were tested during pretreatment.The results showed that there was a significant influence of the ultrasonic assisted KOH pretreatment(KOH(Upt)) on physiochemical characteristics of WS during pretreatment as well as on digester performance.The pretreatment time was optimized to 36 h for all KOH concentrations.The highest total volatile fatty acid(TVFA) productions(3189 mg·L^-1) from 6%KOHupt samples were observed.Similarly,the SEM analysis and FTIR observation revealed that KOH(Upt) effectively disrupted the physical morphology of WS and successful breaking of lignin and hemicellulose linkage between carboxyl groups.Moreover,the highest biogasification(555 ml·(g VS(loaded))^-1) and biomethane productions(282 ml·(g VS(loaded))^-1) from 4%KOH(Upt) digesters,with 69% of biodegradability,indicated significant availability of organic matter from KOH(Upt).The R^2 values(0.993-0.998) in Modified Gompertz Model indicated that the model was feasible to predict methane yield for this study.Similarly,the Bo values for 4%KOH(Upt)(283.30±2.74 ml·(gVS(loaded))^-1) were also in agreement to the experimental methane yield.These results suggested that ultrasonic addition during KOH pretreatment of WS can effectively increase the organic yield during pretreatment.Moreover,the increase in methane production from 4% KOH(Upt) suggested that digester performance can be improved with lower KOH concentrations using this pretreatment.展开更多
Iron and oxalic acids are widely distributed in the atmosphere and easily form ferric oxalate complex(Fe(III)-Ox).The tropospheric aqueous-phase could provide a medium to enable the photo-Fenton reaction with Fe(III)-...Iron and oxalic acids are widely distributed in the atmosphere and easily form ferric oxalate complex(Fe(III)-Ox).The tropospheric aqueous-phase could provide a medium to enable the photo-Fenton reaction with Fe(III)-Ox under solar irradiation.Although the photolysis mechanisms of Fe(III)-Ox have been investigated extensively,information about the oxidation of volatile organic compounds(VOC),specifically the potential for Secondary Organic Aerosol(SOA)formation in the Fe(III)-Ox system,is lacking.In this study,a ubiquitous VOC methacrolein(MACR)is chosen as a model VOC,and the oxidation of MACR with Fe(III)-Ox is investigated under typical atmospheric water conditions.The effects of oxalate concentration,Fe(III)concentration,MACR concentration,and pH on the oxidation of MACR are studied in detail.Results show that the oxidation rate of MACR greatly accelerates in the presence of oxalate when compared with only Fe(III).The oxidation rate of MACR also accelerates with increasing concentration of oxalate.The effect of Fe(III)is found to be more complicated.The oxidation rate of MACR first increases and then decreases with increasing Fe(III)concentration.The oxidation rate of MACR increases monotonically with decreasing pH in the common atmospheric water pH range or with decreasing MACR concentration.The production of ferrous and hydrogen peroxide,pH,and aqueous absorbance are monitored throughout the reaction process.The quenching experiments verify that·OH and O_(2)^(+)are both responsible for the oxidation of MACR.MACR is found to rapidly oxidize into small organic acids with higher boiling points and oligomers with higher molecular weight,which contributes to the yield of SOA.These results suggest that Fe(III)-Ox plays an important role in atmospheric oxidation.展开更多
Cities rely on massive amounts of physical,chemical,and biological resources to support their growth and metabolism.These‘metabolic inputs’are accumulated in cities to form material stocks in buildings,infrastructur...Cities rely on massive amounts of physical,chemical,and biological resources to support their growth and metabolism.These‘metabolic inputs’are accumulated in cities to form material stocks in buildings,infrastructures,transportation facilities,and household appliances.This study takes China’s urbanization as an example to illustrate the characteristics of material stock changes in developing countries and compare them with those in developed countries.Results show that(1)material stocks have been growing in China,but have saturated in developed countries,and(2)the major components of urban metabolism are construction and industrial materials(e.g.,steel)in developing countries but biomass(e.g.,food)in developed countries.The changes in the magnitude and types of material stocks can not only measure urban development but also directly link city and its residents,offering advantages in representing urbanization over the existing indices such as population,land use,or gross domestic product(GDP).Given the new insights provided by material stock,we recommend to embrace it as a critical index of urbanization for guiding urban planning and policy-making.展开更多
The air quality in China has improved significantly in the last decade and,correspondingly,the characteristics of PM_(2.5)have also changed.We studied the interannual variation of PM_(2.5)in Chengdu,one of the most he...The air quality in China has improved significantly in the last decade and,correspondingly,the characteristics of PM_(2.5)have also changed.We studied the interannual variation of PM_(2.5)in Chengdu,one of the most heavily polluted megacities in southwest China,during the most polluted season(winter).Our results show that the mass concentrations of PM_(2.5)decreased significantly year-by-year,from 195.8±91.0μg/m~3in winter 2016 to 96.1±39.3μg/m^(3)in winter 2020.The mass concentrations of organic matter(OM),SO_()4^(2-),NH_(4)^(+)and NO_(3)^(-)decreased by 49.6%,57.1%,49.7% and 28.7%,respectively.The differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO_(3)^(-)and there was a larger contribution from mobile sources.The contribution of OM and NO_(3)^(-)not only increased with increasing levels of pollution,but also increased year-by-year at the same level of pollution.Four sources of PM_(2.5)were identified:combustion sources,vehicular emissions,dust and secondary aerosols.Secondary aerosols made the highest contribution and increased year-by-year,from 40.6%in winter 2016 to 46.3% in winter 2020.By contrast,the contribution from combustion sources decreased from 14.4% to 8.7%.Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants(e.g.,OM and NO_(3)^(-))and sources(secondary aerosols and vehicular emissions)in future policies for the reduction of pollution in Chengdu during the winter months.展开更多
The electrochemical CO_(2)reduction reaction(ECO_(2)RR)to formate is perceived as a technoeconomic pathway for transforming renewable electricity into fuels.However,the indeterminate mechanism underlying structural se...The electrochemical CO_(2)reduction reaction(ECO_(2)RR)to formate is perceived as a technoeconomic pathway for transforming renewable electricity into fuels.However,the indeterminate mechanism underlying structural self-reconstruction obstructs the strategic design of a high-performance In catalyst for the ECO_(2)RR.In this study,we chose InOOH as the model catalyst to illustrate the dynamic structure of In-based catalysts during reconstruction in the ECO_(2)RR.The findings of the current study indicate that the in situ electrochemical reconstruction of crystalline InOOH results in the creation of crystalline In clusters/InOOH,followed by In/InOOH heterostructures,and finally,metallic In over time.The efficiencies of the different phases conformed to the sequence:In clusters/InOOH>In/InOOH heterostructures>metallic In.This progression leads to a continuous drop in maximum current density and Faradaic efficiency from 29.6 mA/cm2 and 87%to 6.3 mA/cm2 and 75%,respectively with time extending to 7200 s,at-1.0 V relative to the reversible hydrogen electrode.Our in situ characterization and theoretical studies highlighted the crucial role of the In-cluster/InOOH interface in CO_(2)activation and conversion.展开更多
The hygroscopicity of atmospheric aerosols significantly influences their size distribution,cloud condensation nuclei ability,atmospheric residence time,and climate forcing.In order to investigate the hygroscopic beha...The hygroscopicity of atmospheric aerosols significantly influences their size distribution,cloud condensation nuclei ability,atmospheric residence time,and climate forcing.In order to investigate the hygroscopic behavior of aerosol particles and serious haze in China,a Hygroscopic Tandem Differential Mobility Analyzers(HTDMA)system was designed and constructed at Fudan University.It can function as a scanning mobility particle sizing system to measure particle size distribution in the range of 20–1000 nm in diameter, as well as a hygroscopicity analyzer for aerosol particles with diameters between 20–400 nm in the range of 20%–90%RH(relative humidity).It can also measure the e?ect of uptake of inorganic acids or semi- VOCs on the hygroscopic behavior of aerosols,such as typical inorganic salts in atmospheric dust or their mixtures.The performance tests show that the system measured particle size of the standard polystyrene latex spheres(PSLs)is 197 nm,which is in excellent agreement with the certified diameter D=199±6 nm, as well as a standard deviation of the repeated runs SD=8.9×10-4.In addition,the measured hygroscopic growth factors of the model compounds,(NH4)2SO4 and NaNO3,agree with the Khler theoretical curves. The results indicate that the HTDMA system is an excellent and powerful tool for studying the hygroscopic behavior of submicron aerosols and meets the demand required for laboratory research and fieldwork on atmospheric aerosols in China.展开更多
A water-stable bimetallic Fe/Zrmetal-organic framework[UiO-66(Fe/Zr)]for exceptional decontamination of arsenic in water was fabricated through a facile one-step strategy.The batch adsorption experiments revealed the ...A water-stable bimetallic Fe/Zrmetal-organic framework[UiO-66(Fe/Zr)]for exceptional decontamination of arsenic in water was fabricated through a facile one-step strategy.The batch adsorption experiments revealed the excellent performances with ultrafast adsorption kinetics due to the synergistic effects of two functional centers and large surface area(498.33 m^(2)/g).The absorption capacity of UiO-66(Fe/Zr)for arsenate[As(V)]and arsenite[As(III)]reached as high as 204.1 mg/g and 101.7 mg/g,respectively.Langmuir model was suitable to describe the adsorption behaviors of arsenic on UiO-66(Fe/Zr).The fast kinetics(adsorption equilibrium in 30min,10mg/L As)and pseudo-second-ordermodel implied the strong chemisorption between arsenic ions and UiO-66(Fe/Zr),which was further confirmed by DFT theoretical calculations.The results of FT-IR,XPS analysis and TCLP test demonstrated that arsenic was immobilized on the surface of UiO-66(Fe/Zr)through Fe/Zr-O-As bonds,and the leaching rates of the adsorbed As(III)and As(V)from the spent adsorbent were only 5.6%and 1.4%,respectively.UiO-66(Fe/Zr)can be regenerated for five cycles without obvious removal efficiency decrease.The original arsenic(1.0mg/L)in lake and tapwater was effectively removed in 2.0 hr[99.0%of As(III)and 99.8%of As(V)].The bimetallic UiO-66(Fe/Zr)has great potentials in water deep purification of arsenic with fast kinetics and high capacity.展开更多
The establishment of the environmental management system in the financial sector can be effectively promoted through the introduction of the environmental protection concept and its implementation by the financial sec...The establishment of the environmental management system in the financial sector can be effectively promoted through the introduction of the environmental protection concept and its implementation by the financial sector.The impact of a sustainable development system on the sector is analyzed in this article from three aspects:environmental risk assessment,financing support for environmental protection projects,and financial services to environmentally friendly corporations and individuals.Influential factors on the development of the environmental management system in China’s financial sector are discussed from the perspective of various entities such as financial institutions,financial regulation authorities,environmental protection departments,corporations,and the public.It is pointed out that China’s financial sector is now in the transitional phase from a defensive attitude to a preventive attitude.Strengthening governmental guidance,the supervision of regulators as well as public awareness of environmental protection should be used to enhance the initiative in the development of the environmental management system in the Chinese financial sector.展开更多
The application of selenium nanoparticles(SeNPs)as nanofertilizers may lead to the release of SeNPs into aquatic systems.However,the environmental behavior of SeNPs is rarely studied.In this study,using alginate-coate...The application of selenium nanoparticles(SeNPs)as nanofertilizers may lead to the release of SeNPs into aquatic systems.However,the environmental behavior of SeNPs is rarely studied.In this study,using alginate-coated SeNPs(Alg-SeNPs)and polyvinyl alcohol-coated SeNPs(PVA-SeNPs)as models,we systematically investigated the aggregation and stability of SeNPs under various water conditions.PVA-SeNPs were highly stable in mono-and polyvalent electrolytes,probably due to the strong steric hindrance of the capping agent.Alg-SeNPs only suffered from a limited increase in size,even at 2500 mmol/L NaCl and 200 mmol/L MgCl_(2),while they underwent apparent aggregation in CaCl_(2) and LaCl_(3) solutions.The binding of Ca^(2+) and La^(3+) with the guluronic acid part in alginate induced the formation of cross-linking aggregates.Natural organic matter enhanced the stability of Alg-SeNPs in monovalent electrolytes,while accelerated the attachment of Alg-SeNPs in polyvalent electrolytes,due to the cation bridge effects.The long-term stability of SeNPs in natural water showed that the aggregation sizes of Alg-SeNPs and PVA-SeNPs increased to several hundreds of nanometers or above 10μm after 30 days,implying that SeNPs may be suspended in the water column or further settle down,depending on the surrounding water chemistry.The study may contribute to the deep insight into the fate and mobility of SeNPs in the aquatic environment.The varying fate of SeNPs in different natural waters also suggests that the risks of SeNPs to organisms living in diverse depths in the aquatic compartment should be concerned.展开更多
Molybdenum disulfide(MoS_(2))has shown significant promise as an economic hydrogen evolution reaction(HER)catalyst for hydrogen generation,but its catalytic performance is still lower than noble metalbased catalysists...Molybdenum disulfide(MoS_(2))has shown significant promise as an economic hydrogen evolution reaction(HER)catalyst for hydrogen generation,but its catalytic performance is still lower than noble metalbased catalysists.Herein,a silver nanoparticles(Ag NPs)-decorated 1T/2H phase layered MoS_(2) electrocatalyst grown on titanium dioxide nanorod arrays(Ag NPs/1T(2H)MoS_(2)/TNRs)was prepared through acid-tunable ammonium ion intercalation.Taking advantage of MoS_(2) layered structure and crystal phase controllability,as-prepared Ag NPs/1T(2H)MoS_(2)/TNRs exhibited ultrahigh HER activity.As-proposed strategy combines facile hydrogen desorption(Ag NPs)with efficient hydrogen adsorption(1T/2H MoS_(2))effectively circumventes the kinetic limitation of hydrogen desorption by 1T/2H MoS_(2).The as-prepared Ag NPs/1T(2H)MoS_(2)/TNRs electrocatalyst exhibited excellent HER activity in 0.5 mol/L H2SO4 with low overpotential(118 mV vs.reversible hydrogen electrode(RHE))and small Tafel slope(38.61 mV/dec).The overpotential exhibts no obvious attenuation after 10 h of constant current flow.First-principles calculation demonstrates that as-prepared 1T/2H MoS_(2) exhibit a large capacity to store protons.These protons can be subsequently transferred to Ag NPs,which significantly increases the hydrogen coverage on the surface of Ag NPs in HER process and thus change the rate-determining step of HER on Ag NPs from water dissociation to hydrogen recombination.This study provides a unique strategy to improve the catalytic activity and stability for MoS_(2)-based electrocatalyst.展开更多
Over the last several decades,scientists have established a wealth of evidence to demonstrate the risks posed to human health by toxic elements in atmospheric particulate matter(PM).Antimony(Sb),as one of ever ignored...Over the last several decades,scientists have established a wealth of evidence to demonstrate the risks posed to human health by toxic elements in atmospheric particulate matter(PM).Antimony(Sb),as one of ever ignored PM-bound heavy metals,attracts more and more attentions and has been regarded as one emerging air pollutant with the change of pollution sources of particulate matter.To study the distribution of Sb in PM with different particle sizes is of great practical significance for understanding its source and health risks.In this study,the size distributions of Sb in PM(PM_(2.5),PM_(10)and TSP)in different seasons were studied from July 2018 to May 2019.The high concentration of PM-bound Sb was found and the health risk was evaluated.Sb was enriched in fine particles and showed higher values in winter,which was probably caused by coal combustion and meteorological conditions.It was also found that traffic-related non-exhaust emissions might become another main contribution to fine particle Sb.Health risk assessment demonstrated that the hazard quotient(HQ)of Sb in PM_(2.5)and PM_(10)for children(PM_(2.5):1.54,PM_(10):1.32)exceeded the acceptable threshold and ingestion contributed the most to the HQ for both children and adults.展开更多
Atmospheric nanoparticles are crucial components contributing to fine particulate matter(PM_(2.5)),and therefore have significant effects on visibility,climate,and human health.Due to the unique role of atmospheric na...Atmospheric nanoparticles are crucial components contributing to fine particulate matter(PM_(2.5)),and therefore have significant effects on visibility,climate,and human health.Due to the unique role of atmospheric nanoparticles during the evolution process from gas-phase molecules to larger particles,a number of sophisticated experimental techniques have been developed and employed for online monitoring and characterization of the physical and chemical properties of atmospheric nanoparticles,helping us to better understand the formation and growth of new particles.In this paper,we firstly review these state-of-the-art techniques for investigating the formation and growth of atmospheric nanoparticles(e.g.,the gas-phase precursor species,molecular clusters,physicochemical properties,and chemical composition).Secondly,we present findings from recent field studies on the formation and growth of atmospheric nanoparticles,utilizing several advanced techniques.Further-more,perspectives are proposed for technique development and improvements in measuring atmospheric nanoparticles.展开更多
La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy...La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Furthermore, the adsorption properties of La-EDTA-Fe3O4 toward phosphate in water were investigated. The uptake rate of phosphate in water by La-EDTA-Fe3O4 was 3-1000 times than that of EDTA-Fe3O4 , and reached 97.8% at 7 hr. The adsorption process agreed well with the Freundlich model and kinetics studies showed that the adsorption of phosphate proceeds according to pseudo second-order adsorption kinetics. The maximum removal rate was achieved at pH 6.0-7.0. The La-EDTA-Fe3O4 had good adsorption properties and could be separated well from aqueous solution by a permanent magnet. Therefore, this nanomaterial has potential application for the removal of phosphate from large water bodies.展开更多
Atmospheric pollutants including SO_2, NO_2, CO, O_3 and inhalable particulate matter(PM2.5 and PM10) were monitored continuously from March 2014 to February 2015 to investigate characteristics of air pollution at Lha...Atmospheric pollutants including SO_2, NO_2, CO, O_3 and inhalable particulate matter(PM2.5 and PM10) were monitored continuously from March 2014 to February 2015 to investigate characteristics of air pollution at Lhasa, Tibetan Plateau. Species exhibited similar seasonal variations except O_3, with the peaks in winter but low valleys in summer. The maximum O_3 concentration was observed in spring, followed by summer, autumn, and winter. The positive correlation between O_3 and PM10 in spring indicated similar sources of them, and was assumed to be turbulent transport. Temperature was the dominant meteorological factor for most species in spring. High temperature accelerates O_3 photochemistry, and favors air disturbance which is conductive to dust resuspension in spring. Relative humidity(RH) and atmospheric pressure were the main meteorological factors in summer. RH showed negative correlations with species, while atmospheric pressure posed opposite situation. Wind speed(WS) was the dominant meteorological factor in autumn, the negative correlations between WS and species indicated diffusion by wind. Most species showed non-significant correlations with meteorological factors in winter, indicating the dependence of pollution on source emission rather than restriction by meteorology. Pollution weather character indicated that emissions were from biomass burning and dust suspension, and meteorological factors also played an important role. Air stream injection from the stratosphere was observed during O_3 pollution period. Air parcels from Southwest Asia were observed during air pollution period in winter. An enhancement in air pollutants such as O_3 would be expected in the future, more attention should be given to countermeasures for prevention of air pollution in the future.展开更多
Recently,heterogeneous activation of peroxymonosulfate(PMS) to oxidatively degrade organic pollutants has been a hotspot.In the present work,copper ferrite-graphite oxide hybrid(CuFe2 O4@GO)was prepared and used as ca...Recently,heterogeneous activation of peroxymonosulfate(PMS) to oxidatively degrade organic pollutants has been a hotspot.In the present work,copper ferrite-graphite oxide hybrid(CuFe2 O4@GO)was prepared and used as catalyst to activate PMS for degradation of methylene blue(MB) in aqueous solution.A high degradation efficiency(93.3%) was achieved at the experimental conditions of20 mg/L MB,200 mg/L CuFe2 O4@GO,0.8 mmol/L PMS,and 25℃temperature.Moreover,CuFe2 O4@GO showed an excellent reusability and stability.The effects of various operational parameters including pollutant type,solution pH,catalyst dosage,PMS dosage,pollutant concentration,temperature,natural organic matter(NOM),and inorganic anions on the catalytic degradation process were comprehensively investigated and elucidated.The further mechanistic study revealed the Cu(Ⅱ)/Cu(Ⅰ) redox couple on CuFe2 O4@GO played the dominant role in PMS activation,where both hydroxyl and sulfate radicals were generated and proceeded the degradation of pollutants.In general,CuFe2 O4@GO is a promising heterocatalyst for PMS-based advanced oxidation processes(AOPs) in wastewater treatment.展开更多
Bismuth-based material has been broadly studied due to their potential applications in various areas,especially used as promising photocatalysts for the removal of persistent organic pollutants(POPs) and several appro...Bismuth-based material has been broadly studied due to their potential applications in various areas,especially used as promising photocatalysts for the removal of persistent organic pollutants(POPs) and several approaches have been adopted to tailor their features.Herein,the bismuth-based photocatalysts(BiOCl,BiPO4,BiOPO4/BiOCl) were synthesized by hydrothermal method and advanced characterization techniques(XRD,SEM,EDS elemental mapping,Raman and UV-vis DRS) were employed to analyze their morphology,crystal structure,and purity of the prepared photocatalysts.These synthesized photocatalysts offered a praiseworthy activity as compared to commercial TiO2(P25) for the degradation of model pollutant perfluorooctanoic acid(PFOA) under 254 nm UV light.It was interesting to observe that all synthesized photocatalysts show significant degradation of PFOA and their photocatalytic activity follows the order:bismuth-based catalysts> TiO2(P25)> without catalyst.Bismuth-based catalysts degraded the PFOA by almost 99.99% within 45 min while this degradation efficiency was 66.05% with TiO2 under the same reaction condition.Our work shows that the bismuth-based photocatalysts are promising in PFOA treatment.展开更多
Tunnel displays a typical semi-closed environment, and multitudes of the pollutants tend to accumulate. The samples of gaseous pollutants and particulate matter(PM) were collected from the Xiangyin tunnel at Shanghai ...Tunnel displays a typical semi-closed environment, and multitudes of the pollutants tend to accumulate. The samples of gaseous pollutants and particulate matter(PM) were collected from the Xiangyin tunnel at Shanghai to investigate the characteristics of the pollutant emissions. The results indicated that both gaseous pollutants and PM exhibited much higher concentrations during the rush hours in the morning and at night due to vehicle emission. Two peaks of the PM concentration were observed in the scope of 0.7‐1.1 and 3.3–4.7 μm, accounting for 14.6% and 20.3% of the total concentrations, respectively.Organic matter(OM), EC, and many water-soluble ions were markedly higher at the rush hours in the morning than those at night, implicating comprehensive effects of vehicle types and traffic volume. The particle number concentrations exhibited two peaks at Aitken mode(25 nm and 100 nm) and accumulation mode(600 nm), while the particle volume concentration displayed high values at the accumulation mode(100–500 nm) and coarse mode(2.5–4.0 μm). The peak around 100 nm was detected in the morning rush hours, but it diminished with the decrease of the traffic volume. Individual-particle analysis revealed that main particles in the tunnel were Fe-rich particles, K-rich particles, mineral particles,Ca–S rich particles and Al–Si particles. The particles collected at the rush hours displayed marked different morphologies, element concentrations and particle sizes compared to the ones collected at the non-rush period. The data presented herein could shed a light on the feature of vehicle emissions.展开更多
基金supported by the National Natural Science Foundation of China(22006044,22006043)External Cooperation Program of Science and Technology Planning of Fujian Province(2023I0018)+2 种基金the Fujian Province Science and Technology Program Funds(2020H6013)the National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2020A03)the Scientific Research Funds of Huaqiao University(605-50Y200270001)。
文摘The Co_(3)O_(4)nanoparticles,dominated by a catalytically active(110)lattice plane,were synthesized as a low-temperature NO_(x) adsorbent to control the cold start emissions from vehicles.These nanoparticles boast a substantial quantity of active chemisorbed oxygen and lattice oxygen,which exhibited a NO_(x) uptake capacity commensurate with Pd/SSZ-13 at 100℃.The primary NO_(x) release temperature falls within a temperature range of 200-350℃,making it perfectly suitable for diesel engines.The characterization results demonstrate that chemisorbed oxygen facilitate nitro/nitrites intermediates formation,contributing to the NO_(x) storage at 100℃,while the nitrites begin to decompose within the 150-200℃range.Fortunately,lattice oxygen likely becomes involved in the activation of nitrites into more stable nitrate within this particular temperature range.The concurrent processes of nitrites decomposition and its conversion to nitrates results in a minimal NO_(x) release between the temperatures of 150-200℃.The nitrate formed via lattice oxygen mainly induces the NO_(x) to be released as NO_(2) within a temperature range of 200-350℃,which is advantageous in enhancing the NO_(x) activity of downstream NH_(3)-SCR catalysts,by boosting the fast SCR reaction pathway.Thanks to its low cost,considerable NO_(x) absorption capacity,and optimal release temperature,Co_(3)O_(4)demonstrates potential as an effective material for passive NO_(x) adsorber applications.
基金Supported by University Grant Commission,New Delhi,India[Grant No.F.14-2(SC)/2010(SA-Ⅲ)]
文摘Adansonia digitata L.(Malvaceae) is commonly known as baobab tree native to Africa.Baobab is a multi-purpose tree which offers protection and provides food,clothing and medicine as well as raw material for many useful items.The fruit pulp,seeds,leaves,flowers.roots,and bark of baobab are edible and they have been studied by scientists for their useful properties.The fruit pulp have very high vitamin C.calcium,phosphorus,carbohydrates,fibers,potassium,proteins and lipids content,which can be used in seasoning as an appetizer and also make juices.Seeds contain appreciable quantities of phosphorus,magnesium,zinc,sodium,iron,manganese,whereas they have high levels of lysine,thiamine,calcium and iron.Baobab has numerous biological properties including antimicrobial,anti-malarial,diarrhoea,anaemia,asthma,antiviral,anti-oxidant and anti-inflammatory activities amongst others.Phytochemical investigation revealed the presence of flavonoids.phytosterols.amino acids,fatty acids,vitamins and minerals.The review summarizes the information on various aspects of traditional information,taxonomic description,medicinal properties and importantly nutritional value.
基金supported by the National Key Research and Development Program of China (2018YFC0214103)the National Natural Science Foundation of China (22006044)the Scientific Research Funds of Huaqiao University (605-50Y200270001)。
文摘In this work,the characterizations of Cu-SSZ-13 after hydrothermal aging(HTA)and thermal aging(TA)at different temperatures(750,800,and 850°C)are compared,and the differences between those two serious aged samples are analyzed.With this data,the effect of steam on catalysts deactivation during hydrothermal aging is analyzed.The TA at 750 and 800°C causes the dealumination and the agglomeration of Cu^(2+)ions to Cu O,resulting in the activity loss of Cu-SSZ-13.The presence of steam upon HTA at750 and 800°C aggravates the catalyst deactivation by increasing the Al detachment and the Cu^(2+)agglomeration.The structure and cupric state are almost the same in the Cu-SSZ-13 after TA and HTA at 850°C,respectively,indicating that the steam has little influence on the deactivation.The formation of CuAl_(2)O_(4) spinel is the primary reason for the deactivation after both HTA and TA at 850°C,probably attributed to the strong interaction between Cu^(2+)ions and framework Al sites at high temperatures.
基金supported by Yuan Yi Biomass S&T Company of China(No.H2015198)。
文摘In this study,ultrasonic field was applied during potassium hydroxide(KOH) pretreatment of wheat straw(WS).Three concentrations of KOH(2%,4%,and 6%) were tested during pretreatment.The results showed that there was a significant influence of the ultrasonic assisted KOH pretreatment(KOH(Upt)) on physiochemical characteristics of WS during pretreatment as well as on digester performance.The pretreatment time was optimized to 36 h for all KOH concentrations.The highest total volatile fatty acid(TVFA) productions(3189 mg·L^-1) from 6%KOHupt samples were observed.Similarly,the SEM analysis and FTIR observation revealed that KOH(Upt) effectively disrupted the physical morphology of WS and successful breaking of lignin and hemicellulose linkage between carboxyl groups.Moreover,the highest biogasification(555 ml·(g VS(loaded))^-1) and biomethane productions(282 ml·(g VS(loaded))^-1) from 4%KOH(Upt) digesters,with 69% of biodegradability,indicated significant availability of organic matter from KOH(Upt).The R^2 values(0.993-0.998) in Modified Gompertz Model indicated that the model was feasible to predict methane yield for this study.Similarly,the Bo values for 4%KOH(Upt)(283.30±2.74 ml·(gVS(loaded))^-1) were also in agreement to the experimental methane yield.These results suggested that ultrasonic addition during KOH pretreatment of WS can effectively increase the organic yield during pretreatment.Moreover,the increase in methane production from 4% KOH(Upt) suggested that digester performance can be improved with lower KOH concentrations using this pretreatment.
基金The authors gratefully acknowledge financial support from the Ministry of Science and Technology of the People’s Republic of China(Grant Nos.2017YFC0210005 and 2016YFE0112200).
文摘Iron and oxalic acids are widely distributed in the atmosphere and easily form ferric oxalate complex(Fe(III)-Ox).The tropospheric aqueous-phase could provide a medium to enable the photo-Fenton reaction with Fe(III)-Ox under solar irradiation.Although the photolysis mechanisms of Fe(III)-Ox have been investigated extensively,information about the oxidation of volatile organic compounds(VOC),specifically the potential for Secondary Organic Aerosol(SOA)formation in the Fe(III)-Ox system,is lacking.In this study,a ubiquitous VOC methacrolein(MACR)is chosen as a model VOC,and the oxidation of MACR with Fe(III)-Ox is investigated under typical atmospheric water conditions.The effects of oxalate concentration,Fe(III)concentration,MACR concentration,and pH on the oxidation of MACR are studied in detail.Results show that the oxidation rate of MACR greatly accelerates in the presence of oxalate when compared with only Fe(III).The oxidation rate of MACR also accelerates with increasing concentration of oxalate.The effect of Fe(III)is found to be more complicated.The oxidation rate of MACR first increases and then decreases with increasing Fe(III)concentration.The oxidation rate of MACR increases monotonically with decreasing pH in the common atmospheric water pH range or with decreasing MACR concentration.The production of ferrous and hydrogen peroxide,pH,and aqueous absorbance are monitored throughout the reaction process.The quenching experiments verify that·OH and O_(2)^(+)are both responsible for the oxidation of MACR.MACR is found to rapidly oxidize into small organic acids with higher boiling points and oligomers with higher molecular weight,which contributes to the yield of SOA.These results suggest that Fe(III)-Ox plays an important role in atmospheric oxidation.
基金supported by the National Key Research and Development Program of Ministry of Science and Technology of China(2017YFC0505703)the National Natural Science Foundation of China(41801222)+1 种基金the Key Program of Frontier Science of the Chinese Academy of Sciences(QYZDB-SSW-DQC012)the Fujian Foreign Cooperation Funding(2019I0031).
文摘Cities rely on massive amounts of physical,chemical,and biological resources to support their growth and metabolism.These‘metabolic inputs’are accumulated in cities to form material stocks in buildings,infrastructures,transportation facilities,and household appliances.This study takes China’s urbanization as an example to illustrate the characteristics of material stock changes in developing countries and compare them with those in developed countries.Results show that(1)material stocks have been growing in China,but have saturated in developed countries,and(2)the major components of urban metabolism are construction and industrial materials(e.g.,steel)in developing countries but biomass(e.g.,food)in developed countries.The changes in the magnitude and types of material stocks can not only measure urban development but also directly link city and its residents,offering advantages in representing urbanization over the existing indices such as population,land use,or gross domestic product(GDP).Given the new insights provided by material stock,we recommend to embrace it as a critical index of urbanization for guiding urban planning and policy-making.
基金supported by the National Natural Science Foundation of China(Nos.42205100 and 41805095)the Sichuan Science and Technology Program(Nos.2019YFS0476and 2022NSFSC0982)support from the Sichuan comprehensive monitoring station for environmental air quality。
文摘The air quality in China has improved significantly in the last decade and,correspondingly,the characteristics of PM_(2.5)have also changed.We studied the interannual variation of PM_(2.5)in Chengdu,one of the most heavily polluted megacities in southwest China,during the most polluted season(winter).Our results show that the mass concentrations of PM_(2.5)decreased significantly year-by-year,from 195.8±91.0μg/m~3in winter 2016 to 96.1±39.3μg/m^(3)in winter 2020.The mass concentrations of organic matter(OM),SO_()4^(2-),NH_(4)^(+)and NO_(3)^(-)decreased by 49.6%,57.1%,49.7% and 28.7%,respectively.The differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO_(3)^(-)and there was a larger contribution from mobile sources.The contribution of OM and NO_(3)^(-)not only increased with increasing levels of pollution,but also increased year-by-year at the same level of pollution.Four sources of PM_(2.5)were identified:combustion sources,vehicular emissions,dust and secondary aerosols.Secondary aerosols made the highest contribution and increased year-by-year,from 40.6%in winter 2016 to 46.3% in winter 2020.By contrast,the contribution from combustion sources decreased from 14.4% to 8.7%.Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants(e.g.,OM and NO_(3)^(-))and sources(secondary aerosols and vehicular emissions)in future policies for the reduction of pollution in Chengdu during the winter months.
基金supported by the National Natural Science Foundation of China[22006044]External Cooperation Program of Science and Technology Planning of Fujian Province[2023I0018],National Engineering Laboratory for Mobile Source Emission Control Technology[NELMS2020A03]Scientific Research Funds of Huaqiao University[605-50Y200270001].
文摘The electrochemical CO_(2)reduction reaction(ECO_(2)RR)to formate is perceived as a technoeconomic pathway for transforming renewable electricity into fuels.However,the indeterminate mechanism underlying structural self-reconstruction obstructs the strategic design of a high-performance In catalyst for the ECO_(2)RR.In this study,we chose InOOH as the model catalyst to illustrate the dynamic structure of In-based catalysts during reconstruction in the ECO_(2)RR.The findings of the current study indicate that the in situ electrochemical reconstruction of crystalline InOOH results in the creation of crystalline In clusters/InOOH,followed by In/InOOH heterostructures,and finally,metallic In over time.The efficiencies of the different phases conformed to the sequence:In clusters/InOOH>In/InOOH heterostructures>metallic In.This progression leads to a continuous drop in maximum current density and Faradaic efficiency from 29.6 mA/cm2 and 87%to 6.3 mA/cm2 and 75%,respectively with time extending to 7200 s,at-1.0 V relative to the reversible hydrogen electrode.Our in situ characterization and theoretical studies highlighted the crucial role of the In-cluster/InOOH interface in CO_(2)activation and conversion.
基金support from the National Natural Science Foundation of China(Grant Nos.40533017,40775080,40728006)the key project from the Ministry of Education of China(Grant No.108050)the Research Fund for the Doctoral Program of Higher Education(Grant No.20070246024)
文摘The hygroscopicity of atmospheric aerosols significantly influences their size distribution,cloud condensation nuclei ability,atmospheric residence time,and climate forcing.In order to investigate the hygroscopic behavior of aerosol particles and serious haze in China,a Hygroscopic Tandem Differential Mobility Analyzers(HTDMA)system was designed and constructed at Fudan University.It can function as a scanning mobility particle sizing system to measure particle size distribution in the range of 20–1000 nm in diameter, as well as a hygroscopicity analyzer for aerosol particles with diameters between 20–400 nm in the range of 20%–90%RH(relative humidity).It can also measure the e?ect of uptake of inorganic acids or semi- VOCs on the hygroscopic behavior of aerosols,such as typical inorganic salts in atmospheric dust or their mixtures.The performance tests show that the system measured particle size of the standard polystyrene latex spheres(PSLs)is 197 nm,which is in excellent agreement with the certified diameter D=199±6 nm, as well as a standard deviation of the repeated runs SD=8.9×10-4.In addition,the measured hygroscopic growth factors of the model compounds,(NH4)2SO4 and NaNO3,agree with the Khler theoretical curves. The results indicate that the HTDMA system is an excellent and powerful tool for studying the hygroscopic behavior of submicron aerosols and meets the demand required for laboratory research and fieldwork on atmospheric aerosols in China.
基金This work was supported by the National Natural Science Foundation of China(No.21777040)the Beijing Natural Science Foundation(No.8182051)the Fundamental Research Funds for the Central Universities(No.2017ZZD07).
文摘A water-stable bimetallic Fe/Zrmetal-organic framework[UiO-66(Fe/Zr)]for exceptional decontamination of arsenic in water was fabricated through a facile one-step strategy.The batch adsorption experiments revealed the excellent performances with ultrafast adsorption kinetics due to the synergistic effects of two functional centers and large surface area(498.33 m^(2)/g).The absorption capacity of UiO-66(Fe/Zr)for arsenate[As(V)]and arsenite[As(III)]reached as high as 204.1 mg/g and 101.7 mg/g,respectively.Langmuir model was suitable to describe the adsorption behaviors of arsenic on UiO-66(Fe/Zr).The fast kinetics(adsorption equilibrium in 30min,10mg/L As)and pseudo-second-ordermodel implied the strong chemisorption between arsenic ions and UiO-66(Fe/Zr),which was further confirmed by DFT theoretical calculations.The results of FT-IR,XPS analysis and TCLP test demonstrated that arsenic was immobilized on the surface of UiO-66(Fe/Zr)through Fe/Zr-O-As bonds,and the leaching rates of the adsorbed As(III)and As(V)from the spent adsorbent were only 5.6%and 1.4%,respectively.UiO-66(Fe/Zr)can be regenerated for five cycles without obvious removal efficiency decrease.The original arsenic(1.0mg/L)in lake and tapwater was effectively removed in 2.0 hr[99.0%of As(III)and 99.8%of As(V)].The bimetallic UiO-66(Fe/Zr)has great potentials in water deep purification of arsenic with fast kinetics and high capacity.
基金This work was supported by the National Natural Science Foundation of China(Grant No.70773068)。
文摘The establishment of the environmental management system in the financial sector can be effectively promoted through the introduction of the environmental protection concept and its implementation by the financial sector.The impact of a sustainable development system on the sector is analyzed in this article from three aspects:environmental risk assessment,financing support for environmental protection projects,and financial services to environmentally friendly corporations and individuals.Influential factors on the development of the environmental management system in China’s financial sector are discussed from the perspective of various entities such as financial institutions,financial regulation authorities,environmental protection departments,corporations,and the public.It is pointed out that China’s financial sector is now in the transitional phase from a defensive attitude to a preventive attitude.Strengthening governmental guidance,the supervision of regulators as well as public awareness of environmental protection should be used to enhance the initiative in the development of the environmental management system in the Chinese financial sector.
基金supported by the National Natural Science Foundation of China(Nos.22076198,42192571,and 21827815).
文摘The application of selenium nanoparticles(SeNPs)as nanofertilizers may lead to the release of SeNPs into aquatic systems.However,the environmental behavior of SeNPs is rarely studied.In this study,using alginate-coated SeNPs(Alg-SeNPs)and polyvinyl alcohol-coated SeNPs(PVA-SeNPs)as models,we systematically investigated the aggregation and stability of SeNPs under various water conditions.PVA-SeNPs were highly stable in mono-and polyvalent electrolytes,probably due to the strong steric hindrance of the capping agent.Alg-SeNPs only suffered from a limited increase in size,even at 2500 mmol/L NaCl and 200 mmol/L MgCl_(2),while they underwent apparent aggregation in CaCl_(2) and LaCl_(3) solutions.The binding of Ca^(2+) and La^(3+) with the guluronic acid part in alginate induced the formation of cross-linking aggregates.Natural organic matter enhanced the stability of Alg-SeNPs in monovalent electrolytes,while accelerated the attachment of Alg-SeNPs in polyvalent electrolytes,due to the cation bridge effects.The long-term stability of SeNPs in natural water showed that the aggregation sizes of Alg-SeNPs and PVA-SeNPs increased to several hundreds of nanometers or above 10μm after 30 days,implying that SeNPs may be suspended in the water column or further settle down,depending on the surrounding water chemistry.The study may contribute to the deep insight into the fate and mobility of SeNPs in the aquatic environment.The varying fate of SeNPs in different natural waters also suggests that the risks of SeNPs to organisms living in diverse depths in the aquatic compartment should be concerned.
基金supported by the National Natural Science Foundation of China(No.52270078)the Royal Society IEC\NSFC\211201-International Exchanges 2021 Cost Share(NSFC).
文摘Molybdenum disulfide(MoS_(2))has shown significant promise as an economic hydrogen evolution reaction(HER)catalyst for hydrogen generation,but its catalytic performance is still lower than noble metalbased catalysists.Herein,a silver nanoparticles(Ag NPs)-decorated 1T/2H phase layered MoS_(2) electrocatalyst grown on titanium dioxide nanorod arrays(Ag NPs/1T(2H)MoS_(2)/TNRs)was prepared through acid-tunable ammonium ion intercalation.Taking advantage of MoS_(2) layered structure and crystal phase controllability,as-prepared Ag NPs/1T(2H)MoS_(2)/TNRs exhibited ultrahigh HER activity.As-proposed strategy combines facile hydrogen desorption(Ag NPs)with efficient hydrogen adsorption(1T/2H MoS_(2))effectively circumventes the kinetic limitation of hydrogen desorption by 1T/2H MoS_(2).The as-prepared Ag NPs/1T(2H)MoS_(2)/TNRs electrocatalyst exhibited excellent HER activity in 0.5 mol/L H2SO4 with low overpotential(118 mV vs.reversible hydrogen electrode(RHE))and small Tafel slope(38.61 mV/dec).The overpotential exhibts no obvious attenuation after 10 h of constant current flow.First-principles calculation demonstrates that as-prepared 1T/2H MoS_(2) exhibit a large capacity to store protons.These protons can be subsequently transferred to Ag NPs,which significantly increases the hydrogen coverage on the surface of Ag NPs in HER process and thus change the rate-determining step of HER on Ag NPs from water dissociation to hydrogen recombination.This study provides a unique strategy to improve the catalytic activity and stability for MoS_(2)-based electrocatalyst.
基金supported by the National Natural Science Foundation of China(No.22176056)the Fundamental Research Funds for the Central Universities,China(No.2017ZZD07).
文摘Over the last several decades,scientists have established a wealth of evidence to demonstrate the risks posed to human health by toxic elements in atmospheric particulate matter(PM).Antimony(Sb),as one of ever ignored PM-bound heavy metals,attracts more and more attentions and has been regarded as one emerging air pollutant with the change of pollution sources of particulate matter.To study the distribution of Sb in PM with different particle sizes is of great practical significance for understanding its source and health risks.In this study,the size distributions of Sb in PM(PM_(2.5),PM_(10)and TSP)in different seasons were studied from July 2018 to May 2019.The high concentration of PM-bound Sb was found and the health risk was evaluated.Sb was enriched in fine particles and showed higher values in winter,which was probably caused by coal combustion and meteorological conditions.It was also found that traffic-related non-exhaust emissions might become another main contribution to fine particle Sb.Health risk assessment demonstrated that the hazard quotient(HQ)of Sb in PM_(2.5)and PM_(10)for children(PM_(2.5):1.54,PM_(10):1.32)exceeded the acceptable threshold and ingestion contributed the most to the HQ for both children and adults.
基金supported by the National Key Research and Development Program of China(No.2017YFC0209500)。
文摘Atmospheric nanoparticles are crucial components contributing to fine particulate matter(PM_(2.5)),and therefore have significant effects on visibility,climate,and human health.Due to the unique role of atmospheric nanoparticles during the evolution process from gas-phase molecules to larger particles,a number of sophisticated experimental techniques have been developed and employed for online monitoring and characterization of the physical and chemical properties of atmospheric nanoparticles,helping us to better understand the formation and growth of new particles.In this paper,we firstly review these state-of-the-art techniques for investigating the formation and growth of atmospheric nanoparticles(e.g.,the gas-phase precursor species,molecular clusters,physicochemical properties,and chemical composition).Secondly,we present findings from recent field studies on the formation and growth of atmospheric nanoparticles,utilizing several advanced techniques.Further-more,perspectives are proposed for technique development and improvements in measuring atmospheric nanoparticles.
基金supported by the National Natural Science Foundation of China (No.21007014, 21107024)the Start Foundation of Hunan Agricultural University (No.10YJ01)+2 种基金the National Science and Technology Major Projects (No.2009ZX07212-001-05)the National Environmental Protection Public Welfare Program (No.201009047)the Scientific Research Fund of Hunan Provincial Education Department (No.11C0650)
文摘La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Furthermore, the adsorption properties of La-EDTA-Fe3O4 toward phosphate in water were investigated. The uptake rate of phosphate in water by La-EDTA-Fe3O4 was 3-1000 times than that of EDTA-Fe3O4 , and reached 97.8% at 7 hr. The adsorption process agreed well with the Freundlich model and kinetics studies showed that the adsorption of phosphate proceeds according to pseudo second-order adsorption kinetics. The maximum removal rate was achieved at pH 6.0-7.0. The La-EDTA-Fe3O4 had good adsorption properties and could be separated well from aqueous solution by a permanent magnet. Therefore, this nanomaterial has potential application for the removal of phosphate from large water bodies.
基金supported by the National Natural Science Foundation of China(Nos.21577022,21190053,40975074)Ministry of Science and Technology of China(2016YFC0203700)
文摘Atmospheric pollutants including SO_2, NO_2, CO, O_3 and inhalable particulate matter(PM2.5 and PM10) were monitored continuously from March 2014 to February 2015 to investigate characteristics of air pollution at Lhasa, Tibetan Plateau. Species exhibited similar seasonal variations except O_3, with the peaks in winter but low valleys in summer. The maximum O_3 concentration was observed in spring, followed by summer, autumn, and winter. The positive correlation between O_3 and PM10 in spring indicated similar sources of them, and was assumed to be turbulent transport. Temperature was the dominant meteorological factor for most species in spring. High temperature accelerates O_3 photochemistry, and favors air disturbance which is conductive to dust resuspension in spring. Relative humidity(RH) and atmospheric pressure were the main meteorological factors in summer. RH showed negative correlations with species, while atmospheric pressure posed opposite situation. Wind speed(WS) was the dominant meteorological factor in autumn, the negative correlations between WS and species indicated diffusion by wind. Most species showed non-significant correlations with meteorological factors in winter, indicating the dependence of pollution on source emission rather than restriction by meteorology. Pollution weather character indicated that emissions were from biomass burning and dust suspension, and meteorological factors also played an important role. Air stream injection from the stratosphere was observed during O_3 pollution period. Air parcels from Southwest Asia were observed during air pollution period in winter. An enhancement in air pollutants such as O_3 would be expected in the future, more attention should be given to countermeasures for prevention of air pollution in the future.
基金the Collaborative Innovation Plan of Hubei Province for Key Technologies in the Eco-Ramie Industryfinancially supported by the Natural Science Foundation of Hubei Province,China (No.2018CFB515)the financial support from the National Natural Science Foundation of China (No.41701541)
文摘Recently,heterogeneous activation of peroxymonosulfate(PMS) to oxidatively degrade organic pollutants has been a hotspot.In the present work,copper ferrite-graphite oxide hybrid(CuFe2 O4@GO)was prepared and used as catalyst to activate PMS for degradation of methylene blue(MB) in aqueous solution.A high degradation efficiency(93.3%) was achieved at the experimental conditions of20 mg/L MB,200 mg/L CuFe2 O4@GO,0.8 mmol/L PMS,and 25℃temperature.Moreover,CuFe2 O4@GO showed an excellent reusability and stability.The effects of various operational parameters including pollutant type,solution pH,catalyst dosage,PMS dosage,pollutant concentration,temperature,natural organic matter(NOM),and inorganic anions on the catalytic degradation process were comprehensively investigated and elucidated.The further mechanistic study revealed the Cu(Ⅱ)/Cu(Ⅰ) redox couple on CuFe2 O4@GO played the dominant role in PMS activation,where both hydroxyl and sulfate radicals were generated and proceeded the degradation of pollutants.In general,CuFe2 O4@GO is a promising heterocatalyst for PMS-based advanced oxidation processes(AOPs) in wastewater treatment.
基金financial support from Ministry of Science and Technology of the People’s Republic of China (Nos.2016YFE0112200 and 2016YFC0202700)National Natural Science Foundation of China (Nos.21507011,21677037 and 21607027)Natural Science Foundation of Shanghai (Nos. 19ZR1471200,17ZR1440200)
文摘Bismuth-based material has been broadly studied due to their potential applications in various areas,especially used as promising photocatalysts for the removal of persistent organic pollutants(POPs) and several approaches have been adopted to tailor their features.Herein,the bismuth-based photocatalysts(BiOCl,BiPO4,BiOPO4/BiOCl) were synthesized by hydrothermal method and advanced characterization techniques(XRD,SEM,EDS elemental mapping,Raman and UV-vis DRS) were employed to analyze their morphology,crystal structure,and purity of the prepared photocatalysts.These synthesized photocatalysts offered a praiseworthy activity as compared to commercial TiO2(P25) for the degradation of model pollutant perfluorooctanoic acid(PFOA) under 254 nm UV light.It was interesting to observe that all synthesized photocatalysts show significant degradation of PFOA and their photocatalytic activity follows the order:bismuth-based catalysts> TiO2(P25)> without catalyst.Bismuth-based catalysts degraded the PFOA by almost 99.99% within 45 min while this degradation efficiency was 66.05% with TiO2 under the same reaction condition.Our work shows that the bismuth-based photocatalysts are promising in PFOA treatment.
基金supported by the National Key R&D Program of China(2016YFC0202700)Ministry of Science and Technology of China(2016YFE0112200)+2 种基金National Natural Science Foundation of China(Nos.21777025,21577022,21190053,40975074)the Marie Sklodowska-Curie Actions(690958-MARSU-RISE2015)the International Cooperation project of Shanghai municipal government(15520711200)
文摘Tunnel displays a typical semi-closed environment, and multitudes of the pollutants tend to accumulate. The samples of gaseous pollutants and particulate matter(PM) were collected from the Xiangyin tunnel at Shanghai to investigate the characteristics of the pollutant emissions. The results indicated that both gaseous pollutants and PM exhibited much higher concentrations during the rush hours in the morning and at night due to vehicle emission. Two peaks of the PM concentration were observed in the scope of 0.7‐1.1 and 3.3–4.7 μm, accounting for 14.6% and 20.3% of the total concentrations, respectively.Organic matter(OM), EC, and many water-soluble ions were markedly higher at the rush hours in the morning than those at night, implicating comprehensive effects of vehicle types and traffic volume. The particle number concentrations exhibited two peaks at Aitken mode(25 nm and 100 nm) and accumulation mode(600 nm), while the particle volume concentration displayed high values at the accumulation mode(100–500 nm) and coarse mode(2.5–4.0 μm). The peak around 100 nm was detected in the morning rush hours, but it diminished with the decrease of the traffic volume. Individual-particle analysis revealed that main particles in the tunnel were Fe-rich particles, K-rich particles, mineral particles,Ca–S rich particles and Al–Si particles. The particles collected at the rush hours displayed marked different morphologies, element concentrations and particle sizes compared to the ones collected at the non-rush period. The data presented herein could shed a light on the feature of vehicle emissions.
