Carbonic anhydrase(CA)as a typical metalloenzyme in biological system can accelerate the hydration/dehydration of carbon dioxide(CO2,the major components of greenhouse gases),which performer with high selectivity,envi...Carbonic anhydrase(CA)as a typical metalloenzyme in biological system can accelerate the hydration/dehydration of carbon dioxide(CO2,the major components of greenhouse gases),which performer with high selectivity,environmental friendliness and superior efficiency.However,the free form of CA is quite expensive(~RMB 3000/100 mg),unstable,and non-reusable as the free form of CA is not easy for recovery from the reaction environment,which severely limits its large-scale industrial applications.The immobilization may solve these problems at the same time.In this context,many efforts have been devoted to improving the chemical and thermal stabilities of CA through immobilization strategy.Very recently,a wide range of available inorganic,organic and hybrid compounds have been explored as carrier materials for CA immobilization,which could not only improve the tolerance of CA in hazardous environments,but also improve the efficiency and recovery to reduce the cost of large-scale application of CA.Several excellent reviews about immobilization methods and application potential of CA have been published.By contrast,in our review,we stressed on the way to better retain the biocatalytic activity of immobilized CA system based on different carrier materials and to solve the problems facing in practical operations well.The concluding remarks are presented with a perspective on constructing efficient CO2 conversion systems through rational combining CA and advanced carrier materials.展开更多
This paper focuses on the heavy metal enrichment and heavy metal pollution degree associated with mining activities in some crops and the soils of different parent materials in the Xiaoqinling Gold Belt.According to t...This paper focuses on the heavy metal enrichment and heavy metal pollution degree associated with mining activities in some crops and the soils of different parent materials in the Xiaoqinling Gold Belt.According to the geochemical analysis results of the soils observed in the gold belt,the soils are most highly enriched in Pb,followed by Cr,Cu,and Zn.Furthermore,they are relatively poor in Hg,Cd,and As.It is also shown that the heavy metals in all kinds of soils have the same geochemical characteristics in the gold belt.As for the crops(such as corn and wheat)in the gold belt,Zn and Cu are the most abundant elements,followed by Pb and Cr.Meanwhile,Hg,Cd,and As were found to have relatively low concentrations in the crops.The heavy metals in wheat and corn have the same geochemical characteristics in the gold belt in general.Compared to the aeolian loess soils and the crops therein,heavy metals are more enriched in diluvial and alluvial soils and the crops therein.As shown by relevant studies,the Hg,Pb,Cd,Cu,and Zn pollution are mainly caused by mining activities.Corn and wheat in the gold belt have a high tendency of risk exposure to heavy metal pollution since they are mostly affected by mining activities and feature high background values of heavy metal concentrations.Furthermore,wheat is more liable to be enriched in heavy metals than corn is grown in all types of soils.The Hg pollution in soils leads to Hg accumulation,increasing the risk of Hg uptake in crops,and further affecting human health.This study will provide a scientific basis for the control and management of heavy metals in farmland soils of mining areas.展开更多
Herein,we reported a method to prepare magnetic sodalite sphere by using the mud from backwash wastewater after polyaluminum chloride(PAC)coagulation.The results showed that approximately 100%of Fe in the wastewater w...Herein,we reported a method to prepare magnetic sodalite sphere by using the mud from backwash wastewater after polyaluminum chloride(PAC)coagulation.The results showed that approximately 100%of Fe in the wastewater was precipitated as flocculent iron mud(FM)by adding PAC.FM was converted to spherical magnetic sodalite(FMP)with a diameter of 3μm via a facile alkali hydrothermal method without adding Al/Si resources or reductant.The product FMP had the saturated magnetization of 10.9 emu g^(-1) and high Zn^(2+)adsorption capacity of 50.6 mg g^(-1).Without coagulation with PAC,the removal rate of Fe from the wastewater was only 92.7%,and the precipitated mud(RM)was converted to irregular particles(RMP),which had weak magnetic response and low capacity of Zn^(2+)adsorption comparing with FMP.With the method,the Fe in backwash wastewater was effectively recycled,and the generated sludge was converted to well-formed sodalite sphere without generating any secondary waste.展开更多
Based on the monitoring data of PM2.5 mass concentration at four national environmental monitoring stations in Anqing City from 2015 to 2018,the monthly and daily variation characteristics of PM2.5 mass concentration ...Based on the monitoring data of PM2.5 mass concentration at four national environmental monitoring stations in Anqing City from 2015 to 2018,the monthly and daily variation characteristics of PM2.5 mass concentration in Anqing were studied.Besides,the relationship between PM2.5 mass concentration and meteorological conditions was analyzed based on the meteorological data of Anqing station in the same period.The results showed that the mass concentration of PM2.5 in Anqing City was high in winter and low in summer,and the diurnal variation curve had two peaks and one valley.Precipitation had a significant effect on the removal of PM2.5,and the relationship between wind speed and PM2.5 mass concentration was more complicated.When the hourly average wind speed was force 1,the mass concentration of PM2.5 was the highest.In winter,the greater the wind speed was,the higher the mass concentration of PM2.5 was.As horizontal visibility was 1-4 km,the mass concentration of PM2.5 was the highest.Under the influence of water mist,it dropped significantly when visibility was less than 1 km.展开更多
This paper mainly was based on the average temperature,precipitation,humidity,and wind direction of Gangcha county from 1960 to 2013.By using wavelet analysis and Mann-Kendall(M-K)mutation analysis,specifically analyz...This paper mainly was based on the average temperature,precipitation,humidity,and wind direction of Gangcha county from 1960 to 2013.By using wavelet analysis and Mann-Kendall(M-K)mutation analysis,specifically analyzed the climate change characteristics in the lake basin area of Gangcha county.The result showed that the climatic change in the lake basin area of Gangcha county is noticeable.The average temperature,average minimum temperature,average maximum temperature,and evaporation showed an increasing trend.But the evaporation in the study area was higher than precipitation.The average relative humidity showed a decreasing trend.And the sunshine and the average wind speed percentage showed a significant decreasing trend.Utilizing the Morelet wavelet,The time series of annual mean temperature,annual evaporation and annual sunshine percentage all have quasi3a and quasi4A periods,and the annual mean precipitation has quasi2–3A,quasi2–5A and quasi2–6A periods,which appear in 1996–2005,1962–1978 and 1978–1996 respectively.The mean annual relative humidity has obvious quasi2–7A and quasi3A time series,which appear from 1960 to 1996,1997 to 2005 and after 2008,respectively.The annual mean wind speed has quasi3–4A and quasi5A time series characteristics,which appear in 1964–1967,1984–1995,after 2009 and 1971–1983,respectively.Through Mann-Kendall(M-K)mutation analysis,it is found that the mutations of evaporation and the average speed of wind are significant.The mutation of evaporation started in 2004,and the mutation of average started in 2003.展开更多
In this paper,RS,GIS and GPS technologies are used to interpret the remote sensing images of the north shore of Qinghai Lake from 1987 to 2014 according to the inversion results of vegetation coverage(FVC),albedo,land...In this paper,RS,GIS and GPS technologies are used to interpret the remote sensing images of the north shore of Qinghai Lake from 1987 to 2014 according to the inversion results of vegetation coverage(FVC),albedo,land surface temperature(LST),soil moisture(WET)and other major parameters after image preprocessing,such as radiometric correction,geometric correction and atmospheric correction.On this basis,the decision tree classification method based on landsat8 remote sensing image is used to classify the desertification land in this area,and the development and change of desertification in this period are analyzed.The results show that the fluctuation of desertification land area in this area increased during the study period,but from 2003 to 2014,the land area of mild desertification,moderate desertification and severe desertification landwere respectively decreased 0.92,145.89 and 29.39 km2,while the area of serious desertification land still has a slow increasing trend.Whether the driving force of desertification change trend in this area is caused by human factors or global change needs to be further studied.展开更多
Land desertification is a widely concerned ecological environment problem.Studying the evolution trend of desertification types is of great significance to prevent and control land desertification.In this study,we app...Land desertification is a widely concerned ecological environment problem.Studying the evolution trend of desertification types is of great significance to prevent and control land desertification.In this study,we applied the decision tree classification method,to study the land area and temporal and spatial change law of different types of desertification in the North Bank of Qinghai Lake area from 1987 to 2014,based on the current land use situation and TM remote sensing image data of Haiyan County,Qinghai Province,The results show that the area of mild desertification land and moderate desertification land in the study area has decreased,while the area of severe desertification land and extreme desertification land has increased significantly in the past 30 years.The area of desertification land decreased by 4.02 km2,of which the area of mild and moderate desertification land decreased by 39.73 km2 and 36.8 km2 respectively,and the area of severe and extreme desertification land increased by 32.78 km2 and 39.73 km2 respectively.As for the mutual transformation relationship,the transformation from severe desertification land to extreme desertification land is the main,and the junction of severe desertification land and extreme desertification land is the sensitive area of transformation.In the north shore of Qinghai Lake,the sandy land tends to expand eastward.The research provides reference basis for local land desertification monitoring,and has a great guidance for local effective land desertification and soil and water conservation.展开更多
Although both the aerobic photocatalytic oxidation of organic pollutants into CO2 and the anaerobic photocatalytic reduction of CO2 into solar fuels have been intensively studied,few efforts have been devoted to combi...Although both the aerobic photocatalytic oxidation of organic pollutants into CO2 and the anaerobic photocatalytic reduction of CO2 into solar fuels have been intensively studied,few efforts have been devoted to combining these carbon-involved photocatalytic oxidation-reduction processes together,by which an artificial photocatalytic carbon cycling process can be established.The key challenge lies in the exploitation of efficient bifunctional photocatalysts,capable of triggering both aerobic oxidation and anaerobic reduction reactions.In this work,a bifunctional ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst is successfully constructed,which not only demonstrates superior aerobic photocatalytic oxidation performance in degrading an organic pollutant(using the dye,Rhodamine B as a model),but also exhibits impressive photocatalytic CO2 reduction performance under anaerobic conditions.Moreover,a direct conversion of Rhodamine B to solar fuels in a one-pot anaerobic reactor can be achieved with the as-prepared ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst.The excellent bifunctional photocatalytic performance of the g-C3N4/Bi/BiVO4 photocatalyst is associated with the formation of efficient S-scheme hybrid junctions,which contribute to promoting the appropriate charge dynamics,and sustaining favorable charge potentials.The formation of the S-scheme heterojunction is supported by scavenger studies and density functional theory calculations.Moreover,the in-situ formed plasmonic metallic Bi nanoparticles in the S-scheme hybrid g-C3N4/Bi/BiVO4 photocatalyst enhances vectorial interfacial electron transfer.This novel bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalyst system provides new insights for the further development of an integrated aerobic-anaerobic reaction system for photocatalytic carbon cycling.展开更多
Microorganisms in natural environments are crucial in maintaining the material and energy cycle and the ecological balance of the environment.However,it is challenging to delineate environmental microbes'actual me...Microorganisms in natural environments are crucial in maintaining the material and energy cycle and the ecological balance of the environment.However,it is challenging to delineate environmental microbes'actual metabolic pathways and intraspecific heterogeneity because most microorganisms cannot be cultivated.Raman spectroscopy is a culture-independent technique that can collect molecular vibration profiles from cells.It can reveal the physiological and biochemical information at the single-cell level rapidly and non-destructively in situ.The first part of this review introduces the principles,advantages,progress,and analytical methods of Raman spectroscopy applied in environmental microbiology.The second part summarizes the applications of Raman spectroscopy combined with stable isotope probing(SIP),fluorescence in situ hybridization(FISH),Raman-activated cell sorting and genomic sequencing,and machine learning in microbiological studies.Finally,this review discusses expectations of Raman spectroscopy and future advances to be made in identifying microorganisms,especially for uncultured microorganisms.展开更多
Water-borne pathogenic bacteria are always the top priority to be removed through disinfection process in water treatment due to their threat to human health. It was necessary to develop novel disinfection methods sin...Water-borne pathogenic bacteria are always the top priority to be removed through disinfection process in water treatment due to their threat to human health. It was necessary to develop novel disinfection methods since the conventional chlorine disinfection was inefficient in inactivating chlorine-resistant bacteria, inducing the viable but non-culturable(VBNC) bacteria and forming disinfection by-products(DBPs). In this study, the inactivation of four model strains including Gram-negative(G), Gram-positive(G) and environmental samples by atmospheric-pressure air-liquid discharge plasma(ALDP) was assessed systematically. The results showed that ALDP was superior in inactivating all of the samples compared with chlorination. During 10 min ALDP treatment, the Gbacteria were completely inactivated, and the Gone was inactivated by more than 4.61 logs. The inactivation of bacteria from a campus lake and a wastewater treatment plant effluent exceeded 99.82% and 97.78%, respectively. For G-bacteria, ALDP resulted in a much lower(10~2~10~3 times) levels of VBNC cells than chlorination. ALDP could effectively remove the chlorine-resistant bacteria. More than 96.41% of the intracellular DNA and 99.99% of the extracellular DNA were removed, whereas it was only 56.35% and 12.82% for chlorination. ALDP had a stronger ability to destroy cell structure than chlorination, presumably due to the existence of ROS( ·OH, ~1Oand O). GC-MS analysis showed that ALDP produced less DBPs than chlorination. These findings provided new insights for the application of discharge plasma in water disinfection, which could be complemental or alternative to the conventional disinfection methods.展开更多
Utilization of carbon dioxide(CO_(2))has become a crucial and anticipated solution to address environmental and ecological issues.Enzymes such as carbonic anhydrase(CA)can efficiently convert CO_(2) into various platf...Utilization of carbon dioxide(CO_(2))has become a crucial and anticipated solution to address environmental and ecological issues.Enzymes such as carbonic anhydrase(CA)can efficiently convert CO_(2) into various platform chemicals under ambient conditions,which offers a promising way for CO_(2) utilization.Herein,we constructed a Pickering interfacial biocatalytic system(PIBS)stabilized by CA‐embedded MOFs(ZIF‐8 and ZIF‐L)for CO_(2) mineralization.Through structure engineering of MOFs and incorporation of Pickering emulsion,the internal and external diffusion processes of CO_(2) during the enzymatic mineralization were greatly intensified.When CO_(2) was ventilated at a flow rate of 50 mL min^(–1) for 1 h,the pH value of PIBS dropped from~8.00 to~6.50,while the average pH value of free system only dropped to~7.15,indicating that the initial reaction rate of CO_(2) mineralization of PIBS is nearly twice that of the free system.After the 8^(th) cycle reaction,PIBS can still produce more than 9.8 mg of CaCO_(3) in 5 min,realizing efficient and continuous mineralization of CO_(2).展开更多
It has been demonstrated that microplastics (MPs) can accumulate heavy metals from the environment and transfer them into organisms via the food chain. However, adsorption and desorption capacities for biodegradable M...It has been demonstrated that microplastics (MPs) can accumulate heavy metals from the environment and transfer them into organisms via the food chain. However, adsorption and desorption capacities for biodegradable MPs relative to those for conventional MPs remain poorly understood. In this study, cadmium (Cd(II)) adsorption and desorption characteristics of polylactic acid (PLA), a typical biodegradable MP, were investigated. Two conventional MPs, i.e., polypropylene (PP) and polyamide (PA) were used for comparison. The maximum Cd(II) adsorption capacities of the MPs studied in the adsorption experiments decreased in the order PA (0.96 ± 0.07 mg/g) > PLA (0.64 ± 0.04 mg/g) > PP (0.22 ± 0.03 mg/g). The Pseudo-second-order kinetic model and Freundlich isothermal model described the Cd(II) adsorption behaviors of PLA MPs well. X-ray photoelectron spectroscopy and two-dimensional Fourier transform infrared correlation spectroscopy analysis indicated that oxygen functional groups were the major and preferential binding sites of PLA MPs, which contributed to their high Cd(II) adsorption capacities. Simulated gastric and intestinal fluids both significantly enhanced the desorption capacities of the examined MPs. Notably, degradation of the PLA MPs during in vitro human digestion made the Cd(II) on the PLA MPs more bioaccessible (19% in the gastric phase and 62% in the intestinal phase) than Cd(II) on the PP and PA MPs. These results indicate the remarkable capacities of biodegradable MPs to accumulate Cd(II) and transfer it to the digestive system and show that biodegradable MPs might pose more severe threats to human health than conventional nonbiodegradable MPs.展开更多
Immobilization is an effective method to promote the application of enzyme industry for improving the stability and realizing recovery of enzyme.To some extent,the performance of immobilized enzyme depends on the choi...Immobilization is an effective method to promote the application of enzyme industry for improving the stability and realizing recovery of enzyme.To some extent,the performance of immobilized enzyme depends on the choice of carrier material.Therefore,the development of new carrier materials has been one of the key issues concerned by enzyme immobilization researchers.In this work,a novel organic–inorganic hybrid material,nickel-carnosine complex(NiCar),was synthesized for the first time by solvothermal method.The obtained NiCar exhibits spherical morphology,hierarchical porosity and abundant unsaturated coordination nickel ions,which provide excellent anchoring sites for the immobilization of proteins.His-tagged organophosphate-degrading enzyme(Opd A)and x-transaminase(ω-TA)were used as model enzymes to evaluate the performance of NiCar as a carrier.By a simple adsorption process,the enzyme molecules can be fixed on the particles of NiCar,and the stability and reusability are significantly improved.The analysis of protein adsorption on NiCar verified that the affinity adsorption between the imidazole functional group on the protein and the unsaturated coordination nickel ions on NiCar was the main force in the immobilization process,which provided an idea way for the development of new enzyme immobilization carriers.展开更多
Designing and fabricating highly efficient photocatalysts for water splitting is a promising strategy to address energy and environmental issues.Cadmium sulfide(CdS)has received significant interest as a photocatalyst...Designing and fabricating highly efficient photocatalysts for water splitting is a promising strategy to address energy and environmental issues.Cadmium sulfide(CdS)has received significant interest as a photocatalyst for visible‐light‐induced hydrogen(H2)generation.However,the severe photocorrosion,high overpotential,rapid charge recombination,and sluggish surface reaction kinetics drastically hinder its practical application in water splitting.Herein,uniform zinc cadmium sulfide(Zn_(0.5)Cd_(0.5)S)nanoparticles were anchored on ultrathin Ni(OH)_(2)nanosheets via a facile solution‐phase approach to form an intimate two‐dimensional(2D)/zero‐dimensional(0D)heterojunction.Under visible light irradiation,the 7%Ni(OH)_(2)/Zn_(0.5)Cd_(0.5)S composite exhibited the highest H2 production rate of 6.87 mmol·h^(–1)·g^(–1)with an apparent quantum yield of 16.8%at 420 nm,which is almost 43 times higher than that of pristine Zn_(0.5)Cd_(0.5)S and considerably higher than that of the Pt/Zn_(0.5)Cd_(0.5)S photocatalyst.The high photoactivity of the 2D/0D Ni(OH)_(2)/Zn_(0.5)Cd_(0.5)S heterojunction can be ascribed to its unique and robust structure,wherein the ultrathin Ni(OH)_(2)nanosheets not only provide an excellent platform for the incorporation of Zn_(0.5)Cd_(0.5)S nanoparticles but also serve as an effective cocatalyst to promote photoinduced electron transfer and offer more active sites for photocatalytic H_(2) generation.This work paves the way toward the development of versatile,low‐cost,and highly efficient 2D/0D heterojunction photocatalysts for solar energy conversion.展开更多
Massive waste aluminum scraps produced from the spent aluminum products have high electron capacity and can be recycled as an attractive alternative to materials based on zerovalent iron(Fe^(0))for the removal of oxid...Massive waste aluminum scraps produced from the spent aluminum products have high electron capacity and can be recycled as an attractive alternative to materials based on zerovalent iron(Fe^(0))for the removal of oxidative contaminants from wastewater.This study thus proposed an approach to fabricate micron-sized sulfidated zero-valent iron-aluminum particles(S-Al^(0)@Fe^(0))with high reactivity,electron selectivity and capacity using recycled waste aluminum scraps.S-Al^(0)@Fe^(0)with a three-layer structure contained zero-valent aluminum(Al^(0))core,Fe^(0) middle layer and iron sulfide(FeS)shell.The rates of chromate(Cr(Ⅵ))removal by S-Al^(0)@Fe^(0)at pH 5.0-9.0 were 1.6-5.9 times greater than that by sulfidated zero-valent iron(S-Fe^(0)).The Cr(Ⅵ)removal capacity of S-Al^(0)@Fe^(0)was 8.2-,11.3-and 46.9-fold greater than those of S-Fe0,zero-valent iron-aluminum(Al^(0)-Fe^(0))and Fe^(0),respectively.The chemical cost of S-Al^(0)@Fe^(0) for the equivalent Cr(Ⅵ)removal was 78.5%lower than that of S-Fe^(0).Negligible release of soluble aluminum during the Cr(Ⅵ)removal was observed.The significant enhancement in the reactivity and capacity of S-Al^(0)@Fe^(0)was partially ascribed to the higher reactivity and electron density of the Al0core than Fe^(0).More importantly,S-Al^(0)@Fe^(0) served as an electric cell to harness the persistent and selective electron transfer from the Al^(0)-Fe^(0) core to Cr(Ⅵ)at the surface via coupling Fe^(0)-Fe^(2+)-Fe^(3+)redox cycles,resulting in a higher electron utilization efficiency.Therefore,S-Al^(0)@Fe^(0) fabricated using recycled waste aluminum scraps can be a cost-effective and environmentally-friendly alternative to S-Fe^(0) for the enhanced removal of oxidative contaminants in industrial wastewater.展开更多
Organic matter-induced mineralization is a green and versatile method for synthesizing hybrid nanostructured materials,where the material properties are mainly influenced by the species of natural biomolecules,linear ...Organic matter-induced mineralization is a green and versatile method for synthesizing hybrid nanostructured materials,where the material properties are mainly influenced by the species of natural biomolecules,linear synthetic polymer,or small molecules,limiting their diversity.Herein,we adopted dendrimer poly(amidoamine)(PAMAM)as the inducer to synthesize organosilica-PAMAM network(OSPN)capsules for mannose isomerase(MIase)encapsulation based on a hard-templating method.The structure of OSPN capsules can be precisely regulated by adjusting the molecular weight and concentration of PAMAM,thereby demonstrating a substantial impact on the kinetic behavior of the MIase@OSPN system.The MIase@OSPN system was used for catalytic production of mannose from Dfructose.A mannose yield of 22.24% was obtained,which is higher than that of MIase in organosilica network capsules and similar to that of the free enzyme.The overall catalytic efficiency(kcat/Km)of the MIase@OSPN system for the substrate D-fructose was up to 0.556 s^(-1)·mmol^(-1)·L.Meanwhile,the MIase@OSPN system showed excellent stability and recyclability,maintaining more than 50% of the yield even after 12 cycles.展开更多
As deep borehole heat exchangers(DBHEs)extract heat from geothermal energy with depth of 2–3 kilometers,the circulation water pressure drop is larger than that of shallow-depth borehole heat exchangers,influenced by ...As deep borehole heat exchangers(DBHEs)extract heat from geothermal energy with depth of 2–3 kilometers,the circulation water pressure drop is larger than that of shallow-depth borehole heat exchangers,influenced by the water flow rates.This paper conducted field tests and simulation analysis to study the heat transfer performance and water circulation resistance of DBHE in coupled,where the natural circulation characteristic has been discovered and analyzed quantitatively.Results show that the water temperature and density variation along DBHE forms the driving force of natural circulation.For mechanical flow rate of 6.0 kg/s and inlet water temperature of 20.0℃,the natural circulation flow rate reaches about 2.2 kg/s with transient heat extraction power of 78.5 kW,without energy consumption of water pumps.And the larger inlet water temperature,smaller mechanical water flow rate,higher inner tube thermal conductivity coefficient and larger depth of DBHE all contribute to the larger natural circulation water flow rate.In addition,the natural circulation could effectively decrease the comprehensive water pressure drops of DBHE,which is about 47.3%smaller than the calculated value of traditional models.Thus the natural circulation characteristic has significant influence on the heat transfer performance of DBHE,and also on the energy performance of whole heat pump systems.展开更多
Fly ash,industry-grade lime and a few oxidizing manganese compound additive were used to prepare the“Oxygen-riched”highly reactive absorbent for simultaneous desulfurization and denitrification.Experiments of simult...Fly ash,industry-grade lime and a few oxidizing manganese compound additive were used to prepare the“Oxygen-riched”highly reactive absorbent for simultaneous desulfurization and denitrification.Experiments of simultaneous desulfurization and denitrification were carried out using the highly reactive absorbent in the flue gas circulating fluidized bed(CFB)system.Removal efficiencies of 94.5%for SO_(2)and 64.2%for NO were obtained respectively.The scanning electron microscope(SEM)and accessory X-ray energy spectrometer were used to observe micro-properties of the samples,including fly ash,common highly reactive absorbent,“Oxygen-riched”highly reactive absorbent and spent absorbent.The white flake layers were observed in the SEM images about surfaces of the common highly reactive absorbent and“Oxygen-riched”one,and the particle surfaces of the spent absorbent were porous.The content of calcium on surface was higher than that of the average in the highly reactive absorbent.The manganese compound additive dispersed uniformly on the surfaces of the“Oxygen-riched”highly reactive absorbent.There was a sulfur peak in the energy spectra pictures of the spent absorbent.The component of the spent absorbent was analyzed with chemical analysis methods,and the results indicated that more nitrogen species appeared in the absorbent except sulfur species,and SO_(2)and NO were removed by chemical absorption according to the experimental results of X-ray energy spectrometer and the chemical analysis.Sulfate being the main desulfurization products,nitrite was the main denitrification ones during the process,in which NO was oxidized rapidly to NO_(2)and absorbed by the chemical reaction.展开更多
The effects of chemical oxygen demand(COD)concentration in the influent on nitrous oxide(N_(2)O)emissions,together with the relationships between N_(2)O and water quality parameters in free water surface constructed w...The effects of chemical oxygen demand(COD)concentration in the influent on nitrous oxide(N_(2)O)emissions,together with the relationships between N_(2)O and water quality parameters in free water surface constructed wetlands,were investigated with laboratoryscale systems.N_(2)O emission and purification performance of wastewater were very strongly dependent on COD concentration in the influent,and the total N_(2)O emission in the system with middle COD influent concentration was the least.The relationships between N_(2)O and the chemical and physical water quality variables were studied by using principal component scores in multiple linear regression analysis to predict N_(2)O flux.The multiple linear regression model against principal components indicated that different water parameters affected N_(2)O flux with different COD concentrations in the influent,but nitrate nitrogen affected N_(2)O flux in all systems.展开更多
Chlorine dioxide(ClO_(2))disinfection usually does not produce halogenated disinfection byproducts,but the formation of the inorganic by-product chlorite(ClO^(–)_(2))is a serious consideration.In this study,the ClO^(...Chlorine dioxide(ClO_(2))disinfection usually does not produce halogenated disinfection byproducts,but the formation of the inorganic by-product chlorite(ClO^(–)_(2))is a serious consideration.In this study,the ClO^(–)_(2)formation rule in the ClO_(2)disinfection of drinking water was investigated in the presence of three representative reductive inorganics and four natural organic matters(NOMs),respectively.Fe^(2+)and S^(2–)mainly reduced ClO_(2)to ClO^(–)_(2)at low concentrations.When ClO_(2)was consumed,the ClO^(–)_(2)would be further reduced by Fe^(2+)and S^(2–),leading to the decrease of ClO^(–)_(2).The reaction efficiency of Mn^(2+)with ClO_(2)was lower than that of Fe^(2+)and S^(2–).It might be the case that Mn O 2 generated by the reaction between Mn^(2+)and ClO_(2)had adsorption and catalytic oxidation on Mn^(2+).However,Mn^(2+)would not reduce ClO^(–)_(2).Among the four NOMs,humic acid and fulvic acid reacted with ClO_(2)actively,followed by bovine serum albumin,while sodium alginate had almost no reaction with ClO_(2).The maximum ClO^(–)_(2)yields of reductive inorganics(70%)was higher than that of NOM(around 60%).The lower the concentration of reductive substances,the more ClO^(–)_(2)could be produced by per unit concentration of reductive substances.The results of the actual water samples showed that both reductive inorganics and NOM played an important role in the formation of ClO^(–)_(2)in disinfection.展开更多
基金the National Natural Science Fundation of China(21776213)Natural Science Fund of Tianjin(19JCYBJC19700)for financial support。
文摘Carbonic anhydrase(CA)as a typical metalloenzyme in biological system can accelerate the hydration/dehydration of carbon dioxide(CO2,the major components of greenhouse gases),which performer with high selectivity,environmental friendliness and superior efficiency.However,the free form of CA is quite expensive(~RMB 3000/100 mg),unstable,and non-reusable as the free form of CA is not easy for recovery from the reaction environment,which severely limits its large-scale industrial applications.The immobilization may solve these problems at the same time.In this context,many efforts have been devoted to improving the chemical and thermal stabilities of CA through immobilization strategy.Very recently,a wide range of available inorganic,organic and hybrid compounds have been explored as carrier materials for CA immobilization,which could not only improve the tolerance of CA in hazardous environments,but also improve the efficiency and recovery to reduce the cost of large-scale application of CA.Several excellent reviews about immobilization methods and application potential of CA have been published.By contrast,in our review,we stressed on the way to better retain the biocatalytic activity of immobilized CA system based on different carrier materials and to solve the problems facing in practical operations well.The concluding remarks are presented with a perspective on constructing efficient CO2 conversion systems through rational combining CA and advanced carrier materials.
基金funded by the survey projects initiated by the Ministry of Natural and Resources of the People’s Republic of China(DD20189220,1212010741003,1212011220224,and 121201011000150022)the Public Welfare Scientific Research Project launched by the Ministry of Natural and Resources of the People’s Republic of China(201111020)+1 种基金the project of 2015 Natural Science Basic Research Program of Shaanxi(2015JM4129)the project of 2016 Fundamental Research Funds for the Central Universities(open fund)(310829161128).
文摘This paper focuses on the heavy metal enrichment and heavy metal pollution degree associated with mining activities in some crops and the soils of different parent materials in the Xiaoqinling Gold Belt.According to the geochemical analysis results of the soils observed in the gold belt,the soils are most highly enriched in Pb,followed by Cr,Cu,and Zn.Furthermore,they are relatively poor in Hg,Cd,and As.It is also shown that the heavy metals in all kinds of soils have the same geochemical characteristics in the gold belt.As for the crops(such as corn and wheat)in the gold belt,Zn and Cu are the most abundant elements,followed by Pb and Cr.Meanwhile,Hg,Cd,and As were found to have relatively low concentrations in the crops.The heavy metals in wheat and corn have the same geochemical characteristics in the gold belt in general.Compared to the aeolian loess soils and the crops therein,heavy metals are more enriched in diluvial and alluvial soils and the crops therein.As shown by relevant studies,the Hg,Pb,Cd,Cu,and Zn pollution are mainly caused by mining activities.Corn and wheat in the gold belt have a high tendency of risk exposure to heavy metal pollution since they are mostly affected by mining activities and feature high background values of heavy metal concentrations.Furthermore,wheat is more liable to be enriched in heavy metals than corn is grown in all types of soils.The Hg pollution in soils leads to Hg accumulation,increasing the risk of Hg uptake in crops,and further affecting human health.This study will provide a scientific basis for the control and management of heavy metals in farmland soils of mining areas.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2019YFE0117900)the National Natural Science Foundation of China(Grant Nos.52070038 and 51878134)the Science and Technology Program of Jilin Province(Grant No.20190303001SF).
文摘Herein,we reported a method to prepare magnetic sodalite sphere by using the mud from backwash wastewater after polyaluminum chloride(PAC)coagulation.The results showed that approximately 100%of Fe in the wastewater was precipitated as flocculent iron mud(FM)by adding PAC.FM was converted to spherical magnetic sodalite(FMP)with a diameter of 3μm via a facile alkali hydrothermal method without adding Al/Si resources or reductant.The product FMP had the saturated magnetization of 10.9 emu g^(-1) and high Zn^(2+)adsorption capacity of 50.6 mg g^(-1).Without coagulation with PAC,the removal rate of Fe from the wastewater was only 92.7%,and the precipitated mud(RM)was converted to irregular particles(RMP),which had weak magnetic response and low capacity of Zn^(2+)adsorption comparing with FMP.With the method,the Fe in backwash wastewater was effectively recycled,and the generated sludge was converted to well-formed sodalite sphere without generating any secondary waste.
文摘Based on the monitoring data of PM2.5 mass concentration at four national environmental monitoring stations in Anqing City from 2015 to 2018,the monthly and daily variation characteristics of PM2.5 mass concentration in Anqing were studied.Besides,the relationship between PM2.5 mass concentration and meteorological conditions was analyzed based on the meteorological data of Anqing station in the same period.The results showed that the mass concentration of PM2.5 in Anqing City was high in winter and low in summer,and the diurnal variation curve had two peaks and one valley.Precipitation had a significant effect on the removal of PM2.5,and the relationship between wind speed and PM2.5 mass concentration was more complicated.When the hourly average wind speed was force 1,the mass concentration of PM2.5 was the highest.In winter,the greater the wind speed was,the higher the mass concentration of PM2.5 was.As horizontal visibility was 1-4 km,the mass concentration of PM2.5 was the highest.Under the influence of water mist,it dropped significantly when visibility was less than 1 km.
基金This work was supported by the National Natural Science Foundation of China“Study on the dynamic mechanism of grassland ecosystem response to climate change in Qinghai Plateau”under grant number U20A2098,and the Second Tibet Plateau Scientific Expedition and Research Program(STEP)under grant number 2019QZKK0804.
文摘This paper mainly was based on the average temperature,precipitation,humidity,and wind direction of Gangcha county from 1960 to 2013.By using wavelet analysis and Mann-Kendall(M-K)mutation analysis,specifically analyzed the climate change characteristics in the lake basin area of Gangcha county.The result showed that the climatic change in the lake basin area of Gangcha county is noticeable.The average temperature,average minimum temperature,average maximum temperature,and evaporation showed an increasing trend.But the evaporation in the study area was higher than precipitation.The average relative humidity showed a decreasing trend.And the sunshine and the average wind speed percentage showed a significant decreasing trend.Utilizing the Morelet wavelet,The time series of annual mean temperature,annual evaporation and annual sunshine percentage all have quasi3a and quasi4A periods,and the annual mean precipitation has quasi2–3A,quasi2–5A and quasi2–6A periods,which appear in 1996–2005,1962–1978 and 1978–1996 respectively.The mean annual relative humidity has obvious quasi2–7A and quasi3A time series,which appear from 1960 to 1996,1997 to 2005 and after 2008,respectively.The annual mean wind speed has quasi3–4A and quasi5A time series characteristics,which appear in 1964–1967,1984–1995,after 2009 and 1971–1983,respectively.Through Mann-Kendall(M-K)mutation analysis,it is found that the mutations of evaporation and the average speed of wind are significant.The mutation of evaporation started in 2004,and the mutation of average started in 2003.
基金supported by the National Natural Science Foundation of China“Study on the dynamic mechanism of grassland ecosystem response to climate change in Qinghai Plateau”under grant number U20A2098the Second Tibet Plateau Scientific Expedition and Research Program(STEP)under grant number 2019QZKK0804.
文摘In this paper,RS,GIS and GPS technologies are used to interpret the remote sensing images of the north shore of Qinghai Lake from 1987 to 2014 according to the inversion results of vegetation coverage(FVC),albedo,land surface temperature(LST),soil moisture(WET)and other major parameters after image preprocessing,such as radiometric correction,geometric correction and atmospheric correction.On this basis,the decision tree classification method based on landsat8 remote sensing image is used to classify the desertification land in this area,and the development and change of desertification in this period are analyzed.The results show that the fluctuation of desertification land area in this area increased during the study period,but from 2003 to 2014,the land area of mild desertification,moderate desertification and severe desertification landwere respectively decreased 0.92,145.89 and 29.39 km2,while the area of serious desertification land still has a slow increasing trend.Whether the driving force of desertification change trend in this area is caused by human factors or global change needs to be further studied.
基金This research was supported by the National Nature&Science Foundation of China“Study on the dynamic mechanism of grassland ecosystem response to climate change in Qinghai Plateau”(No.U20A2098)the second Tibetan plateau scientific expedition and research program(STEP,No.2019QZKK0804)China Huaneng Group Co.Science and Technology Program“The research development and implement on the evaluation technology of wind resource”(No.HNKJ18-H31).
文摘Land desertification is a widely concerned ecological environment problem.Studying the evolution trend of desertification types is of great significance to prevent and control land desertification.In this study,we applied the decision tree classification method,to study the land area and temporal and spatial change law of different types of desertification in the North Bank of Qinghai Lake area from 1987 to 2014,based on the current land use situation and TM remote sensing image data of Haiyan County,Qinghai Province,The results show that the area of mild desertification land and moderate desertification land in the study area has decreased,while the area of severe desertification land and extreme desertification land has increased significantly in the past 30 years.The area of desertification land decreased by 4.02 km2,of which the area of mild and moderate desertification land decreased by 39.73 km2 and 36.8 km2 respectively,and the area of severe and extreme desertification land increased by 32.78 km2 and 39.73 km2 respectively.As for the mutual transformation relationship,the transformation from severe desertification land to extreme desertification land is the main,and the junction of severe desertification land and extreme desertification land is the sensitive area of transformation.In the north shore of Qinghai Lake,the sandy land tends to expand eastward.The research provides reference basis for local land desertification monitoring,and has a great guidance for local effective land desertification and soil and water conservation.
基金financially supported by the National Natural Science Foundation of China(51872341,51572209)the Start-up Funds for High-Level Talents of Sun Yat-sen University(38000-31131105)+1 种基金the Fundamental Research Funds for the Central Universities(19lgzd29)the Science and Technology Program of Guangzhou(201707010095)~~
文摘Although both the aerobic photocatalytic oxidation of organic pollutants into CO2 and the anaerobic photocatalytic reduction of CO2 into solar fuels have been intensively studied,few efforts have been devoted to combining these carbon-involved photocatalytic oxidation-reduction processes together,by which an artificial photocatalytic carbon cycling process can be established.The key challenge lies in the exploitation of efficient bifunctional photocatalysts,capable of triggering both aerobic oxidation and anaerobic reduction reactions.In this work,a bifunctional ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst is successfully constructed,which not only demonstrates superior aerobic photocatalytic oxidation performance in degrading an organic pollutant(using the dye,Rhodamine B as a model),but also exhibits impressive photocatalytic CO2 reduction performance under anaerobic conditions.Moreover,a direct conversion of Rhodamine B to solar fuels in a one-pot anaerobic reactor can be achieved with the as-prepared ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst.The excellent bifunctional photocatalytic performance of the g-C3N4/Bi/BiVO4 photocatalyst is associated with the formation of efficient S-scheme hybrid junctions,which contribute to promoting the appropriate charge dynamics,and sustaining favorable charge potentials.The formation of the S-scheme heterojunction is supported by scavenger studies and density functional theory calculations.Moreover,the in-situ formed plasmonic metallic Bi nanoparticles in the S-scheme hybrid g-C3N4/Bi/BiVO4 photocatalyst enhances vectorial interfacial electron transfer.This novel bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalyst system provides new insights for the further development of an integrated aerobic-anaerobic reaction system for photocatalytic carbon cycling.
基金This work was financially supported by the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.K19313901)the National Natural Science Foundation of China(91851210,42141003)+4 种基金the State Key R&D project of China grant(No.2018YFA0605800)the Stable Support Plan Program of Shenzhen Natural Science Fund(20200925173954005)the Guangdong-Shenzhen Joint Fund(2021B1515120080)the Shenzhen Key Laboratory of Marine Archaea Geo-Omics,Southern University of Science and Technology(ZDSYS201802081843490)the financial support from China Postdoctoral Science Foundation(2020M682769).
文摘Microorganisms in natural environments are crucial in maintaining the material and energy cycle and the ecological balance of the environment.However,it is challenging to delineate environmental microbes'actual metabolic pathways and intraspecific heterogeneity because most microorganisms cannot be cultivated.Raman spectroscopy is a culture-independent technique that can collect molecular vibration profiles from cells.It can reveal the physiological and biochemical information at the single-cell level rapidly and non-destructively in situ.The first part of this review introduces the principles,advantages,progress,and analytical methods of Raman spectroscopy applied in environmental microbiology.The second part summarizes the applications of Raman spectroscopy combined with stable isotope probing(SIP),fluorescence in situ hybridization(FISH),Raman-activated cell sorting and genomic sequencing,and machine learning in microbiological studies.Finally,this review discusses expectations of Raman spectroscopy and future advances to be made in identifying microorganisms,especially for uncultured microorganisms.
基金supported by the Natural Science Foundation of China (Nos. 41861144023 and U2005206)the Natural and Science Guiding Project of Fujian Province (No. 2019H0036)the Xiamen Municipal Bureau of Science and Technology (No. YDZX20203502000003)。
文摘Water-borne pathogenic bacteria are always the top priority to be removed through disinfection process in water treatment due to their threat to human health. It was necessary to develop novel disinfection methods since the conventional chlorine disinfection was inefficient in inactivating chlorine-resistant bacteria, inducing the viable but non-culturable(VBNC) bacteria and forming disinfection by-products(DBPs). In this study, the inactivation of four model strains including Gram-negative(G), Gram-positive(G) and environmental samples by atmospheric-pressure air-liquid discharge plasma(ALDP) was assessed systematically. The results showed that ALDP was superior in inactivating all of the samples compared with chlorination. During 10 min ALDP treatment, the Gbacteria were completely inactivated, and the Gone was inactivated by more than 4.61 logs. The inactivation of bacteria from a campus lake and a wastewater treatment plant effluent exceeded 99.82% and 97.78%, respectively. For G-bacteria, ALDP resulted in a much lower(10~2~10~3 times) levels of VBNC cells than chlorination. ALDP could effectively remove the chlorine-resistant bacteria. More than 96.41% of the intracellular DNA and 99.99% of the extracellular DNA were removed, whereas it was only 56.35% and 12.82% for chlorination. ALDP had a stronger ability to destroy cell structure than chlorination, presumably due to the existence of ROS( ·OH, ~1Oand O). GC-MS analysis showed that ALDP produced less DBPs than chlorination. These findings provided new insights for the application of discharge plasma in water disinfection, which could be complemental or alternative to the conventional disinfection methods.
文摘Utilization of carbon dioxide(CO_(2))has become a crucial and anticipated solution to address environmental and ecological issues.Enzymes such as carbonic anhydrase(CA)can efficiently convert CO_(2) into various platform chemicals under ambient conditions,which offers a promising way for CO_(2) utilization.Herein,we constructed a Pickering interfacial biocatalytic system(PIBS)stabilized by CA‐embedded MOFs(ZIF‐8 and ZIF‐L)for CO_(2) mineralization.Through structure engineering of MOFs and incorporation of Pickering emulsion,the internal and external diffusion processes of CO_(2) during the enzymatic mineralization were greatly intensified.When CO_(2) was ventilated at a flow rate of 50 mL min^(–1) for 1 h,the pH value of PIBS dropped from~8.00 to~6.50,while the average pH value of free system only dropped to~7.15,indicating that the initial reaction rate of CO_(2) mineralization of PIBS is nearly twice that of the free system.After the 8^(th) cycle reaction,PIBS can still produce more than 9.8 mg of CaCO_(3) in 5 min,realizing efficient and continuous mineralization of CO_(2).
基金supported by the Hubei Provincial Natural Science Foundation of China(Nos.2021CF349 and 2020CFA042).
文摘It has been demonstrated that microplastics (MPs) can accumulate heavy metals from the environment and transfer them into organisms via the food chain. However, adsorption and desorption capacities for biodegradable MPs relative to those for conventional MPs remain poorly understood. In this study, cadmium (Cd(II)) adsorption and desorption characteristics of polylactic acid (PLA), a typical biodegradable MP, were investigated. Two conventional MPs, i.e., polypropylene (PP) and polyamide (PA) were used for comparison. The maximum Cd(II) adsorption capacities of the MPs studied in the adsorption experiments decreased in the order PA (0.96 ± 0.07 mg/g) > PLA (0.64 ± 0.04 mg/g) > PP (0.22 ± 0.03 mg/g). The Pseudo-second-order kinetic model and Freundlich isothermal model described the Cd(II) adsorption behaviors of PLA MPs well. X-ray photoelectron spectroscopy and two-dimensional Fourier transform infrared correlation spectroscopy analysis indicated that oxygen functional groups were the major and preferential binding sites of PLA MPs, which contributed to their high Cd(II) adsorption capacities. Simulated gastric and intestinal fluids both significantly enhanced the desorption capacities of the examined MPs. Notably, degradation of the PLA MPs during in vitro human digestion made the Cd(II) on the PLA MPs more bioaccessible (19% in the gastric phase and 62% in the intestinal phase) than Cd(II) on the PP and PA MPs. These results indicate the remarkable capacities of biodegradable MPs to accumulate Cd(II) and transfer it to the digestive system and show that biodegradable MPs might pose more severe threats to human health than conventional nonbiodegradable MPs.
文摘Immobilization is an effective method to promote the application of enzyme industry for improving the stability and realizing recovery of enzyme.To some extent,the performance of immobilized enzyme depends on the choice of carrier material.Therefore,the development of new carrier materials has been one of the key issues concerned by enzyme immobilization researchers.In this work,a novel organic–inorganic hybrid material,nickel-carnosine complex(NiCar),was synthesized for the first time by solvothermal method.The obtained NiCar exhibits spherical morphology,hierarchical porosity and abundant unsaturated coordination nickel ions,which provide excellent anchoring sites for the immobilization of proteins.His-tagged organophosphate-degrading enzyme(Opd A)and x-transaminase(ω-TA)were used as model enzymes to evaluate the performance of NiCar as a carrier.By a simple adsorption process,the enzyme molecules can be fixed on the particles of NiCar,and the stability and reusability are significantly improved.The analysis of protein adsorption on NiCar verified that the affinity adsorption between the imidazole functional group on the protein and the unsaturated coordination nickel ions on NiCar was the main force in the immobilization process,which provided an idea way for the development of new enzyme immobilization carriers.
文摘Designing and fabricating highly efficient photocatalysts for water splitting is a promising strategy to address energy and environmental issues.Cadmium sulfide(CdS)has received significant interest as a photocatalyst for visible‐light‐induced hydrogen(H2)generation.However,the severe photocorrosion,high overpotential,rapid charge recombination,and sluggish surface reaction kinetics drastically hinder its practical application in water splitting.Herein,uniform zinc cadmium sulfide(Zn_(0.5)Cd_(0.5)S)nanoparticles were anchored on ultrathin Ni(OH)_(2)nanosheets via a facile solution‐phase approach to form an intimate two‐dimensional(2D)/zero‐dimensional(0D)heterojunction.Under visible light irradiation,the 7%Ni(OH)_(2)/Zn_(0.5)Cd_(0.5)S composite exhibited the highest H2 production rate of 6.87 mmol·h^(–1)·g^(–1)with an apparent quantum yield of 16.8%at 420 nm,which is almost 43 times higher than that of pristine Zn_(0.5)Cd_(0.5)S and considerably higher than that of the Pt/Zn_(0.5)Cd_(0.5)S photocatalyst.The high photoactivity of the 2D/0D Ni(OH)_(2)/Zn_(0.5)Cd_(0.5)S heterojunction can be ascribed to its unique and robust structure,wherein the ultrathin Ni(OH)_(2)nanosheets not only provide an excellent platform for the incorporation of Zn_(0.5)Cd_(0.5)S nanoparticles but also serve as an effective cocatalyst to promote photoinduced electron transfer and offer more active sites for photocatalytic H_(2) generation.This work paves the way toward the development of versatile,low‐cost,and highly efficient 2D/0D heterojunction photocatalysts for solar energy conversion.
基金supported by the National Natural Science Foundation of China(No.42177358)the Natural Science Foundation of Guangdong Province(No.2023A1515011232)。
文摘Massive waste aluminum scraps produced from the spent aluminum products have high electron capacity and can be recycled as an attractive alternative to materials based on zerovalent iron(Fe^(0))for the removal of oxidative contaminants from wastewater.This study thus proposed an approach to fabricate micron-sized sulfidated zero-valent iron-aluminum particles(S-Al^(0)@Fe^(0))with high reactivity,electron selectivity and capacity using recycled waste aluminum scraps.S-Al^(0)@Fe^(0)with a three-layer structure contained zero-valent aluminum(Al^(0))core,Fe^(0) middle layer and iron sulfide(FeS)shell.The rates of chromate(Cr(Ⅵ))removal by S-Al^(0)@Fe^(0)at pH 5.0-9.0 were 1.6-5.9 times greater than that by sulfidated zero-valent iron(S-Fe^(0)).The Cr(Ⅵ)removal capacity of S-Al^(0)@Fe^(0)was 8.2-,11.3-and 46.9-fold greater than those of S-Fe0,zero-valent iron-aluminum(Al^(0)-Fe^(0))and Fe^(0),respectively.The chemical cost of S-Al^(0)@Fe^(0) for the equivalent Cr(Ⅵ)removal was 78.5%lower than that of S-Fe^(0).Negligible release of soluble aluminum during the Cr(Ⅵ)removal was observed.The significant enhancement in the reactivity and capacity of S-Al^(0)@Fe^(0)was partially ascribed to the higher reactivity and electron density of the Al0core than Fe^(0).More importantly,S-Al^(0)@Fe^(0) served as an electric cell to harness the persistent and selective electron transfer from the Al^(0)-Fe^(0) core to Cr(Ⅵ)at the surface via coupling Fe^(0)-Fe^(2+)-Fe^(3+)redox cycles,resulting in a higher electron utilization efficiency.Therefore,S-Al^(0)@Fe^(0) fabricated using recycled waste aluminum scraps can be a cost-effective and environmentally-friendly alternative to S-Fe^(0) for the enhanced removal of oxidative contaminants in industrial wastewater.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFC210-2300)the National Key Research and Development Program of China(Grant No.2022YFC2105902)+2 种基金Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(Grant No.TSBICIP-KJGG-003)Open Funding Project of the State Key Laboratory of Biochemical Engineering of China(Grant No.2020KF-06)Haihe Laboratory of Sustainable Chemical Transformations.
文摘Organic matter-induced mineralization is a green and versatile method for synthesizing hybrid nanostructured materials,where the material properties are mainly influenced by the species of natural biomolecules,linear synthetic polymer,or small molecules,limiting their diversity.Herein,we adopted dendrimer poly(amidoamine)(PAMAM)as the inducer to synthesize organosilica-PAMAM network(OSPN)capsules for mannose isomerase(MIase)encapsulation based on a hard-templating method.The structure of OSPN capsules can be precisely regulated by adjusting the molecular weight and concentration of PAMAM,thereby demonstrating a substantial impact on the kinetic behavior of the MIase@OSPN system.The MIase@OSPN system was used for catalytic production of mannose from Dfructose.A mannose yield of 22.24% was obtained,which is higher than that of MIase in organosilica network capsules and similar to that of the free enzyme.The overall catalytic efficiency(kcat/Km)of the MIase@OSPN system for the substrate D-fructose was up to 0.556 s^(-1)·mmol^(-1)·L.Meanwhile,the MIase@OSPN system showed excellent stability and recyclability,maintaining more than 50% of the yield even after 12 cycles.
基金support from the National Natural Science Foundation of China(Grant No.52308095)the National Key Research and Development Program of China(Grant No.2022YFE0197400)the Natural Science Foundation of Hubei Province of China(Grant No.2024AFB586).
文摘As deep borehole heat exchangers(DBHEs)extract heat from geothermal energy with depth of 2–3 kilometers,the circulation water pressure drop is larger than that of shallow-depth borehole heat exchangers,influenced by the water flow rates.This paper conducted field tests and simulation analysis to study the heat transfer performance and water circulation resistance of DBHE in coupled,where the natural circulation characteristic has been discovered and analyzed quantitatively.Results show that the water temperature and density variation along DBHE forms the driving force of natural circulation.For mechanical flow rate of 6.0 kg/s and inlet water temperature of 20.0℃,the natural circulation flow rate reaches about 2.2 kg/s with transient heat extraction power of 78.5 kW,without energy consumption of water pumps.And the larger inlet water temperature,smaller mechanical water flow rate,higher inner tube thermal conductivity coefficient and larger depth of DBHE all contribute to the larger natural circulation water flow rate.In addition,the natural circulation could effectively decrease the comprehensive water pressure drops of DBHE,which is about 47.3%smaller than the calculated value of traditional models.Thus the natural circulation characteristic has significant influence on the heat transfer performance of DBHE,and also on the energy performance of whole heat pump systems.
基金This work was supported by the Significant Pre-research Foundat ion of the North China Electric Power University.
文摘Fly ash,industry-grade lime and a few oxidizing manganese compound additive were used to prepare the“Oxygen-riched”highly reactive absorbent for simultaneous desulfurization and denitrification.Experiments of simultaneous desulfurization and denitrification were carried out using the highly reactive absorbent in the flue gas circulating fluidized bed(CFB)system.Removal efficiencies of 94.5%for SO_(2)and 64.2%for NO were obtained respectively.The scanning electron microscope(SEM)and accessory X-ray energy spectrometer were used to observe micro-properties of the samples,including fly ash,common highly reactive absorbent,“Oxygen-riched”highly reactive absorbent and spent absorbent.The white flake layers were observed in the SEM images about surfaces of the common highly reactive absorbent and“Oxygen-riched”one,and the particle surfaces of the spent absorbent were porous.The content of calcium on surface was higher than that of the average in the highly reactive absorbent.The manganese compound additive dispersed uniformly on the surfaces of the“Oxygen-riched”highly reactive absorbent.There was a sulfur peak in the energy spectra pictures of the spent absorbent.The component of the spent absorbent was analyzed with chemical analysis methods,and the results indicated that more nitrogen species appeared in the absorbent except sulfur species,and SO_(2)and NO were removed by chemical absorption according to the experimental results of X-ray energy spectrometer and the chemical analysis.Sulfate being the main desulfurization products,nitrite was the main denitrification ones during the process,in which NO was oxidized rapidly to NO_(2)and absorbed by the chemical reaction.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50508019)the National Natural Science Foundation of China-Japan Science and Technology Agency(NSFC-JST)Strategic Joint Research Project(Grant No.50721140117).
文摘The effects of chemical oxygen demand(COD)concentration in the influent on nitrous oxide(N_(2)O)emissions,together with the relationships between N_(2)O and water quality parameters in free water surface constructed wetlands,were investigated with laboratoryscale systems.N_(2)O emission and purification performance of wastewater were very strongly dependent on COD concentration in the influent,and the total N_(2)O emission in the system with middle COD influent concentration was the least.The relationships between N_(2)O and the chemical and physical water quality variables were studied by using principal component scores in multiple linear regression analysis to predict N_(2)O flux.The multiple linear regression model against principal components indicated that different water parameters affected N_(2)O flux with different COD concentrations in the influent,but nitrate nitrogen affected N_(2)O flux in all systems.
基金supported by the National Key Research and Development Program of China(No.2018YFD0900805)the Practice Innovation Program of Postgraduates in Jiangsu Province(No.SJCX20_0306)。
文摘Chlorine dioxide(ClO_(2))disinfection usually does not produce halogenated disinfection byproducts,but the formation of the inorganic by-product chlorite(ClO^(–)_(2))is a serious consideration.In this study,the ClO^(–)_(2)formation rule in the ClO_(2)disinfection of drinking water was investigated in the presence of three representative reductive inorganics and four natural organic matters(NOMs),respectively.Fe^(2+)and S^(2–)mainly reduced ClO_(2)to ClO^(–)_(2)at low concentrations.When ClO_(2)was consumed,the ClO^(–)_(2)would be further reduced by Fe^(2+)and S^(2–),leading to the decrease of ClO^(–)_(2).The reaction efficiency of Mn^(2+)with ClO_(2)was lower than that of Fe^(2+)and S^(2–).It might be the case that Mn O 2 generated by the reaction between Mn^(2+)and ClO_(2)had adsorption and catalytic oxidation on Mn^(2+).However,Mn^(2+)would not reduce ClO^(–)_(2).Among the four NOMs,humic acid and fulvic acid reacted with ClO_(2)actively,followed by bovine serum albumin,while sodium alginate had almost no reaction with ClO_(2).The maximum ClO^(–)_(2)yields of reductive inorganics(70%)was higher than that of NOM(around 60%).The lower the concentration of reductive substances,the more ClO^(–)_(2)could be produced by per unit concentration of reductive substances.The results of the actual water samples showed that both reductive inorganics and NOM played an important role in the formation of ClO^(–)_(2)in disinfection.
