Water soluble organic carbon (WSOC) is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WS...Water soluble organic carbon (WSOC) is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WSOC extracted from 7 soils differently managed. WSOC was extracted from soil with water (soil/water ratio of 1:2, W/V) for 30 min, and then tested for biodegradability by a liquid state respirometric test. Result obtained confirmed the finding that WSOC biodegradability depended on the both land use and management practice. These results suggested the biodegradability test as suitable method to characterize WSOC, and provided useful information to soil fertility.展开更多
Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction tempera...Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction temperature, pH value, and salt on the water extractable organic matter (WEOM) was determined by means of the UV absorbance, fluorescence excitation-emission matrix, and derived fluorescence indexes. In general, the carbon content and aromaticity of WEOM increased with the increasing of extraction temperature, with the exception that there was no significant difference in the amount at 0 and 20℃. More fluorophores, especially microbially-derived organic matter were extracted at high temperature. The pH values of extractant, including 5, 7, and 10, showed no effect on the carbon amount of WEOM, whereas the aromaticity and microbially-derived component gradually increased with the increasing of pH values. The fluorescence intensity of humic acid-like fluorophore was stronger in neutral and alkali condition than that in acidic condition. The addition of 10 mmol L-1 CaCl2 significantly decreased the carbon amount of recovered WEOM. Moreover, it significantly decreased the aromaticity of WEOM and the quantity of fulvic acid-like and humic acid-like fluorophores, whereas increased the percentage of tyrosine-like and tryptophan-like fluorophores in the total fluorophores and the amount of microbially-derived organic matter. Generally, 10 mmol L-1 KCl showed the same influence trend, but with low influence degree.展开更多
Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect ...Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient (k) of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions (〈 63 μm, 63-100 μm, and 100-300 μm). The total concentration of WSOC in sediments (Cwsoc) and k were estimated using multiple water-sediment ratio experiments. Results showed that Cwsoc ranged from 0.012 to 0.022 mg/g, while k ranged from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions (〈 63 μm), k is higher in larger size fractions (63- 100 μm and 100-300 μm) related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy (FT-IR) at 3400 and 1430 cm^-1 implied that the lowest k was related to the highest concentration of acidic humic groups in particles 〈 63 μm. WSOC in finer fractions (〈 63 μm) is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water.展开更多
Fluorescence excitation and average molecular weight of 46 water soluble organic matter (WSOC) samples extracted from 20 soil types in eastern China were determined. It was found all samples shared similar spectrosco...Fluorescence excitation and average molecular weight of 46 water soluble organic matter (WSOC) samples extracted from 20 soil types in eastern China were determined. It was found all samples shared similar spectroscopy. A good linear relationship existed between total organic carbon and excitation in the range of 350 to 450 nm though the content of organic carbon and pH of the samples vary in a wide range. No significant correlation between relative excitation intensity and average molecular weight of WSOC and FA was found, but the partial correlation became significant with pH as the controlling factor for WSOC samples. The relative excitation intensity showed a general trend of increasing from south to north in the study area. The pH value might play an important role in regulating the fluorescent spatial variation of WSOC. S153 A展开更多
In this paper the effect of ion-exchange simplified as water handling on basic zeolitewas studied.It was foond that the interaction between chemisorbed water and Na+-O2- couplewould increase the total number of basic ...In this paper the effect of ion-exchange simplified as water handling on basic zeolitewas studied.It was foond that the interaction between chemisorbed water and Na+-O2- couplewould increase the total number of basic sites, while weaken the intensity of each basic sites.Theprocess can be explained by the adsorb model of organic acid on NaX presented before.展开更多
Purification of surface water is widely practiced with conventional water treatment processes like coagulation-flocculation, sedimentation, filtration,and disinfection. Some reports have specified that conventional wa...Purification of surface water is widely practiced with conventional water treatment processes like coagulation-flocculation, sedimentation, filtration,and disinfection. Some reports have specified that conventional wastewater purification processes do not effectively remove many chemical contaminants,展开更多
Along the recently evacuated shores of the retreating Dead Sea black mud deposits have been exposed and hence subjected to head ward erosion resulting in landslides and land collapses threatening herewith the infrastr...Along the recently evacuated shores of the retreating Dead Sea black mud deposits have been exposed and hence subjected to head ward erosion resulting in landslides and land collapses threatening herewith the infrastructure in the area. The geotechnical and mineralogical characterization of the black mud show the presence of a variety of clays including smectite, kaolinite, illite, montmorollinite and muscovite with a natural water content near the liquid limit. These geotechnical and mineralogical properties indicate that the mud is prone to rapid erosion and sliding, which actually hit the area and have until now caused damages and degrading topography and geology in the area. The study also refers the origin of the black mud and its organic content to the erosion and deposition of Upper Cretaceous-Tertiary oil shale deposits formerly covering the whole surrounding areas of the Dead Sea. The study suggests engineering solutions to the geologic degradation processes in the area, before further damage to the infrastructure takes place.展开更多
This paper is a critical review of current knowledge of organic chloramines in water systems,including their formation, stability, toxicity, analytical methods for detection, and their impact on drinking water treatme...This paper is a critical review of current knowledge of organic chloramines in water systems,including their formation, stability, toxicity, analytical methods for detection, and their impact on drinking water treatment and quality. The term organic chloramines may refer to any halogenated organic compounds measured as part of combined chlorine(the difference between the measured free and total chlorine concentrations), and may include N-chloramines,N-chloramino acids, N-chloraldimines and N-chloramides. Organic chloramines can form when dissolved organic nitrogen or dissolved organic carbon react with either free chlorine or inorganic chloramines. They are potentially harmful to humans and may exist as an intermediate for other disinfection by-products. However, little information is available on the formation or occurrence of organic chloramines in water due to a number of challenges. One of the biggest challenges for the identification and quantification of organic chloramines in water systems is the lack of appropriate analytical methods. In addition, many of the organic chloramines that form during disinfection are unstable, which results in difficulties in sampling and detection. To date research has focussed on the study of organic monochloramines.However, given that breakpoint chlorination is commonly undertaken in water treatment systems, the formation of organic dichloramines should also be considered. Organic chloramines can be formed from many different precursors and pathways. Therefore, studying the occurrence of their precursors in water systems would enable better prediction and management of their formation.展开更多
The sorption of water and organic vapors on valnemulin hydrochloride was determined by dynamic vapor sorption at 25℃. The adsorption-desorption behavior of water vapor and a series of organic vapors was investigated ...The sorption of water and organic vapors on valnemulin hydrochloride was determined by dynamic vapor sorption at 25℃. The adsorption-desorption behavior of water vapor and a series of organic vapors was investigated to probe the structural changes in valnemulin hydrochloride before and after sorption. The isothermal adsorption equilibrium data was evaluated using Guggenheim-Anderson-deBoer (GAB) and Bru- nauer-Emmett-Teller (BET) models. The BET model is applicable only at low relative pressures (0.1 ≤ RP ≤ 0.4) while the GAB model is applicable in the whole range of RPs (0.1 ≤RP≤0.9). The sorption kinetics at high RPs was determined by fitting the sorption data to the Avrami equation and the sorption content vs. time relationship could be predicted by the Avrami equation. Finally, the possible sorption mechanism of valnemulin hydrochloride was also discussed.展开更多
Municipal wastewater reclamation is becoming of increasing importance in the world to solve the problem of water scarcity. A better understanding of the molecular composition of effluent organic matter(Ef OM) in the...Municipal wastewater reclamation is becoming of increasing importance in the world to solve the problem of water scarcity. A better understanding of the molecular composition of effluent organic matter(Ef OM) in the treated effluents of municipal wastewater treatment plants(WWTPs) is crucial for ensuring the safety of water reuse. In this study, the molecular composition of Ef OM in the secondary effluent of a WWTP in Beijing and the reclaimed water further treated with a coagulation–sedimentation–ozonation process were characterized using a non-target Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS) method and compared to that of natural organic matter(NOM) in the local source water from a reservoir. It was found that the molecular composition of Ef OM in the secondary effluent and reclaimed water was dominated by CHOS formulas, while NOM in the source water was dominated by CHO formulas. The CHO formulas of the three samples had similar origins. Anthropogenic surfactants were responsible for the CHOS formulas in Ef OM of the secondary effluent and were not well removed by the coagulation-sedimentation-ozonation treatment process adopted.展开更多
Biological soil disinfestation is an effective method to control soil-borne disease by flooding and incorporating with organic amendments, but field conditions and resources sometimes limited its practical application...Biological soil disinfestation is an effective method to control soil-borne disease by flooding and incorporating with organic amendments, but field conditions and resources sometimes limited its practical application. A laboratory experiment was conducted to develop practice guidelines on controlling Fusarium wilt, a widespread banana disease caused by Fusarium oxysporum f. sp. cubense(FOC). FOC infested soil incorporated with rice or maize straw at rates of 1.5 tons/ha and 3.0 tons/ha was incubated under flooded or water-saturated(100% water holding capacity) conditions at 30℃ for 30 days. Results showed that FOC populations in the soils incorporated with either rice or maize straw rapidly reduced more than 90% in the first 15 days and then fluctuated till the end of incubation, while flooding alone without organic amendment reduced FOC populations slightly. The rapid and dramatic decrease of redox potential(down to- 350 m V) in straw-amended treatments implied that both anaerobic condition and strongly reductive soil condition would contribute to pathogen inactivation. Water-saturation combined with straw amendments had the comparable effects on reduction of FOC, indicating that flooding was not indispensable for inactivating FOC. There was no significant difference in the reduction of FOC observed in the straw amendments at between 1.5 and 3 tons/ha. Therefore,incorporating soil with straw(rice or maize straw) at a rate of 3.0 tons/ha under 100%water holding capacity or 1.5 tons/ha under flooding, would effectively alleviate banana Fusarium wilt caused by FOC after 15-day treating under 30℃.展开更多
This study investigated the partitioning behavior of dissolved organic matter(DOM) in liquid and ice phases, as well as the changes in the optical properties and chlorine reactivity of DOM during the freezing proces...This study investigated the partitioning behavior of dissolved organic matter(DOM) in liquid and ice phases, as well as the changes in the optical properties and chlorine reactivity of DOM during the freezing processes of water. DOM was rejected from the ice phase and accumulated in the remaining liquid phase during water freezing. Moreover, the decrease in freezing temperature, as well as the increase in dissolved organic carbon(DOC)concentration of feed water, caused an increase in DOM captured in the ice phase. The ultraviolet-absorbing compounds, trihalomethane precursors, as well as fulvic acid- and humic acid-like fluorescent materials, were more liable to be to be rejected from the ice phase and were more easily retained in the unfrozen liquid phase during water freezing, as compared with organics(on average) that comprise DOC. In addition, it was also found a higher accumulation of these organics in the unfrozen liquid phase during water freezing at higher temperature. The freeze/thaw processes altered the quantity, optical properties, and chlorine reactivity of DOM. The decrease in ultraviolet light at 254 nm as well as the production of aromatic protein- and soluble microbial byproduct-like fluorescent materials in DOM due to freeze/thaw were consistently observed. On the other hand, the changes in DOC, trihalomethane formation potential, and fulvic acid- and humic acid-like fluorescence caused by freeze/thaw varied significantly between samples.展开更多
The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds(WSOCs) and their effects on ammonium sulfate(AS) and sodium chloride were investigated using a hygroscopicity ta...The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds(WSOCs) and their effects on ammonium sulfate(AS) and sodium chloride were investigated using a hygroscopicity tandem differential mobility analyzer(HTDMA) in the relative humidity(RH) range of 5%–90%. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model(E-AIM) and Zdanovskii–Stokes–Robinson(ZSR) method. The equal mass multicomponent WSOCs mixture containing levoglucosan, succinic acid, phthalic acid and humic acid showed gradual water uptake without obvious phase change over the whole RH range. It was found that the organic content played an important role in the water uptake of mixed particles.When organic content was dominant in the mixture(75%), the measured hygroscopic growth was higher than predictions from the E-AIM or ZSR relation, especially under high RH conditions. For mass fractions of organics not larger than 50%, the hygroscopic growth of mixtures was in good agreement with model predictions. The influence of interactions between inorganic and organic components on the hygroscopicity of mixed particles was related to the salt type and organic content. These results could contribute to understanding of the hygroscopic behaviors of multicomponent aerosol particles.展开更多
Anion exchange resins (AERs) with different properties were evaluated for their ability to remove dissolved organic matter (DOM) and bromide, and to reduce disinfection by-product (DBP) formation potentials of w...Anion exchange resins (AERs) with different properties were evaluated for their ability to remove dissolved organic matter (DOM) and bromide, and to reduce disinfection by-product (DBP) formation potentials of water collected from a eutrophic surface water source in Japan. DOM and bromide were simultaneously removed by all selected AERs in batch adsorption experiments. A polyacrylic magnetic ion exchange resin (MIEX) showed faster dissolved organic carbon (DOC) removal than other AERs because it had the smallest resin bead size. Aromatic DOM fractions with molecular weight larger than 1600 Da and fluorescent organic fractions of fulvic acid- and humic acid-like compounds were efficiently removed by all AERs. Polystyrene AERs were more effective in bromide removal than polyacrylic AERs. This result implied that the properties of AERs, i.e. material and resin size, influenced not only DOM removal but also bromide removal efficiency, MIEX showed significant chlorinated DBP removal because it had the highest DOC removal within 30 rain, whereas polystyrene AERs efficiently removed brominated DBPs, especially brominated trihalomethane species. The results suggested that, depending on source water DOM and bromide concentration, selecting a suitable AER is a key factor in effective control of chlorinated and brominated DBPs in drinking water.展开更多
The nanotechnology industry advances rapidly,and at the vanguard are the promising silver nanoparticles(Ag NPs),which have diverse applications.These nanometer-sized particles have been shown to inhibit the ability ...The nanotechnology industry advances rapidly,and at the vanguard are the promising silver nanoparticles(Ag NPs),which have diverse applications.These nanometer-sized particles have been shown to inhibit the ability of bacteria to produce adenosine triphosphate(ATP),a molecule necessary for chemical energy transport in cells.The antimicrobial properties of Ag NPs(and Ag+)make them valued antibacterial展开更多
Environmental water samples can be extremely complex,with potentially thousands of molecules that can derive from natural organic matter(NOM)and thousands that derive from anthropogenic contaminants.As complex as th...Environmental water samples can be extremely complex,with potentially thousands of molecules that can derive from natural organic matter(NOM)and thousands that derive from anthropogenic contaminants.As complex as these samples are,drinking water can be even more complex.Due to disinfectants that are used to treat drinking water(e.g.,chlorine,chloramines,展开更多
PM(2.5) samples were collected in Zhengzhou during 3 years of observation, and chemical characteristics and source contribution were analyzed. Approximately 96% of the daily PM(2.5) concentrations and annual avera...PM(2.5) samples were collected in Zhengzhou during 3 years of observation, and chemical characteristics and source contribution were analyzed. Approximately 96% of the daily PM(2.5) concentrations and annual average values exceeded the Chinese National Ambient Air Quality Daily and Annual Standards, indicating serious PM(2.5) pollution. The average concentration of water-soluble inorganic ions was 2.4 times higher in heavily polluted days(daily PM32.5 concentrations > 250 μg/mand visibility < 3 km) than that in other days, with sulfate, nitrate, and ammonium as major ions. According to the ratio of NO-3/SO2-4,stationary sources are still the dominant source of PM(2.5) and vehicle emission could not be ignored. The ratio of secondary organic carbon to organic carbon indicated that photochemical reactivity in heavily polluted days was more intense than in other days.Crustal elements were the most abundant elements, accounting for more than 60% of 23 elements. Chemical Mass Balance results indicated that the contributions of major sources(i.e., nitrate, sulfate, biomass, carbon and refractory material, coal combustion, soil dust,vehicle, and industry) of PM(2.5) were 13%, 16%, 12%, 2%, 14%, 8%, 7%, and 8% in heavily polluted days and 20%, 18%, 9%, 2%, 27%, 14%, 15%, and 9% in other days, respectively.Extensive combustion activities were the main sources of polycyclic aromatic hydrocarbons during the episode(Jan 1-9, 2015) and the total benzo[a]pyrene equivalency concentrations in heavily polluted days present significant health threat. Because of the effect of regional transport, the pollution level of PM(2.5) in the study area was aggravated.展开更多
TiO2 has been everlastingly employed as popular photocatalyst for water splitting. However, the wide band gap (3.0-3.2 eV) and poor absorption to visible light of TiO2 result in a low utilization of solar energy and...TiO2 has been everlastingly employed as popular photocatalyst for water splitting. However, the wide band gap (3.0-3.2 eV) and poor absorption to visible light of TiO2 result in a low utilization of solar energy and limit its large-scale application. To decrease its band gap and promote the utilization of full solar energy, we here modified TiO2 by in situ growth of N-rich covalent organic polymer (termed as COPuM). During the in situ growth of COPuM on the surface of TiO2, intimate contacts between TiO2 and COPuM were built and core-shell structures were finally formed. The derived TiO2@COPHM demon-strated a narrower band gap (2.53 eV) compared to raw TiO2 (3.13 eV) and improved absorption to visible light. The optimal TiO2@COPHM hybrid exhibited excellent hydrogen evolution performance of 162.7μmol h^-1 under simulated sunlight which was more than 3 times higher than raw TiO2 (51.3μmol h^-1). Particularly, visible light hydrogen evolution rate of TiO2@COPHM reached 0.65 μmol h^-1 while non-hydrogen generation was observed using raw TiO2.展开更多
Atmospheric fine particles (PM2.5) were collected in this study with middle volume samplers in Fuzhou, China, during both normal days and haze days in summer (September 2007) and winter (january 2008). The conce...Atmospheric fine particles (PM2.5) were collected in this study with middle volume samplers in Fuzhou, China, during both normal days and haze days in summer (September 2007) and winter (january 2008). The concentrations, distributions, and sources of polycyclic aromatic hydrocarbons (PAHs), organic carbon (OC), elemental carbon (EC), and water soluble inorganic ions (WSIls) were determinated. The results showed that the concentrations of PM2.s, PAHs, OC, EC, and WSIIs were in the orders of haze 〉 normal and winter〉 summer. The dominant PAHs of PM2.s in Fuzhou were Fluo, Pyr, Chr, BbF, BkF, BaP, BghiP, and IcdP, which represented about 80.0% of the total PAHs during different sampling periods. The BaPeq concentrations of ^-~PAHs were 0.78, 0.99, 1.22, and 2.43 ng/m3 in summer normal, summer haze, winter normal, and winter haze, respectively. Secondary pollutants (SO42 , NO3 , NH4*, and OC) were the major chemical compositions of PM2.5, accounting for 69.0%, 55.1%, 63.4%, and 64.9% of PM2.s mass in summer normal, summer haze, winter normal, and winter haze, respectively. Correspondingly, secondary organic carbon (SOC) in Fuzhou accounted for 20.1%, 48.6%, 24.5%, and 50.5% of OC. The average values of nitrogen oxidation ratio (NOR) and sulfur oxidation ratio (SOR) were higher in haze days (0.08 and 0.27) than in normal days (0.05 and 0.22). Higher OC/EC ratios were also found in haze days (5.0) than in normal days (3.3). Correlation analysis demonstrated that visibility had positive correlations with wind speed, and neg- ative correlations with relative humidity and major air pollutants. Overall, the enrichments of PM2.5, OC, EC, SO42 ,andNO3 promoted haze formation. Furthermore, the diagnostic ratios of IcdP/(IcdP + BghiP), lcdP/BghiP, OC/EC, and NO3 /SO42 indicated that vehicle exhaust and coal consumption were the main sources of pollutants in Fuzhou.展开更多
文摘Water soluble organic carbon (WSOC) is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WSOC extracted from 7 soils differently managed. WSOC was extracted from soil with water (soil/water ratio of 1:2, W/V) for 30 min, and then tested for biodegradability by a liquid state respirometric test. Result obtained confirmed the finding that WSOC biodegradability depended on the both land use and management practice. These results suggested the biodegradability test as suitable method to characterize WSOC, and provided useful information to soil fertility.
基金supported by the National Natural Science Foundation of China (51109089 and 31071862)
文摘Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction temperature, pH value, and salt on the water extractable organic matter (WEOM) was determined by means of the UV absorbance, fluorescence excitation-emission matrix, and derived fluorescence indexes. In general, the carbon content and aromaticity of WEOM increased with the increasing of extraction temperature, with the exception that there was no significant difference in the amount at 0 and 20℃. More fluorophores, especially microbially-derived organic matter were extracted at high temperature. The pH values of extractant, including 5, 7, and 10, showed no effect on the carbon amount of WEOM, whereas the aromaticity and microbially-derived component gradually increased with the increasing of pH values. The fluorescence intensity of humic acid-like fluorophore was stronger in neutral and alkali condition than that in acidic condition. The addition of 10 mmol L-1 CaCl2 significantly decreased the carbon amount of recovered WEOM. Moreover, it significantly decreased the aromaticity of WEOM and the quantity of fulvic acid-like and humic acid-like fluorophores, whereas increased the percentage of tyrosine-like and tryptophan-like fluorophores in the total fluorophores and the amount of microbially-derived organic matter. Generally, 10 mmol L-1 KCl showed the same influence trend, but with low influence degree.
基金supported by the Major State Basic Research Program of China (No. 2007CB407202)the National Natural Science Foundation of China (No. 40501063).
文摘Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient (k) of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions (〈 63 μm, 63-100 μm, and 100-300 μm). The total concentration of WSOC in sediments (Cwsoc) and k were estimated using multiple water-sediment ratio experiments. Results showed that Cwsoc ranged from 0.012 to 0.022 mg/g, while k ranged from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions (〈 63 μm), k is higher in larger size fractions (63- 100 μm and 100-300 μm) related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy (FT-IR) at 3400 and 1430 cm^-1 implied that the lowest k was related to the highest concentration of acidic humic groups in particles 〈 63 μm. WSOC in finer fractions (〈 63 μm) is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water.
基金National Natural Science Foundation of China No. 40024101
文摘Fluorescence excitation and average molecular weight of 46 water soluble organic matter (WSOC) samples extracted from 20 soil types in eastern China were determined. It was found all samples shared similar spectroscopy. A good linear relationship existed between total organic carbon and excitation in the range of 350 to 450 nm though the content of organic carbon and pH of the samples vary in a wide range. No significant correlation between relative excitation intensity and average molecular weight of WSOC and FA was found, but the partial correlation became significant with pH as the controlling factor for WSOC samples. The relative excitation intensity showed a general trend of increasing from south to north in the study area. The pH value might play an important role in regulating the fluorescent spatial variation of WSOC. S153 A
文摘In this paper the effect of ion-exchange simplified as water handling on basic zeolitewas studied.It was foond that the interaction between chemisorbed water and Na+-O2- couplewould increase the total number of basic sites, while weaken the intensity of each basic sites.Theprocess can be explained by the adsorb model of organic acid on NaX presented before.
基金supported by grants from Science and Technology Planning Project of Shenzhen [No.200703079]
文摘Purification of surface water is widely practiced with conventional water treatment processes like coagulation-flocculation, sedimentation, filtration,and disinfection. Some reports have specified that conventional wastewater purification processes do not effectively remove many chemical contaminants,
文摘Along the recently evacuated shores of the retreating Dead Sea black mud deposits have been exposed and hence subjected to head ward erosion resulting in landslides and land collapses threatening herewith the infrastructure in the area. The geotechnical and mineralogical characterization of the black mud show the presence of a variety of clays including smectite, kaolinite, illite, montmorollinite and muscovite with a natural water content near the liquid limit. These geotechnical and mineralogical properties indicate that the mud is prone to rapid erosion and sliding, which actually hit the area and have until now caused damages and degrading topography and geology in the area. The study also refers the origin of the black mud and its organic content to the erosion and deposition of Upper Cretaceous-Tertiary oil shale deposits formerly covering the whole surrounding areas of the Dead Sea. The study suggests engineering solutions to the geologic degradation processes in the area, before further damage to the infrastructure takes place.
基金the Australian Research Council (LP110100548 and LP130100602)Water Corporation of Western Australia+3 种基金Water Research AustraliaCurtin University for supporting this studyCurtin University (Curtin International Postgraduate Research Scholarship)Water Research Australia (WaterRA PhD Scholarship)
文摘This paper is a critical review of current knowledge of organic chloramines in water systems,including their formation, stability, toxicity, analytical methods for detection, and their impact on drinking water treatment and quality. The term organic chloramines may refer to any halogenated organic compounds measured as part of combined chlorine(the difference between the measured free and total chlorine concentrations), and may include N-chloramines,N-chloramino acids, N-chloraldimines and N-chloramides. Organic chloramines can form when dissolved organic nitrogen or dissolved organic carbon react with either free chlorine or inorganic chloramines. They are potentially harmful to humans and may exist as an intermediate for other disinfection by-products. However, little information is available on the formation or occurrence of organic chloramines in water due to a number of challenges. One of the biggest challenges for the identification and quantification of organic chloramines in water systems is the lack of appropriate analytical methods. In addition, many of the organic chloramines that form during disinfection are unstable, which results in difficulties in sampling and detection. To date research has focussed on the study of organic monochloramines.However, given that breakpoint chlorination is commonly undertaken in water treatment systems, the formation of organic dichloramines should also be considered. Organic chloramines can be formed from many different precursors and pathways. Therefore, studying the occurrence of their precursors in water systems would enable better prediction and management of their formation.
基金This research was financially supported by National Natural Science Foundation of China (Grant No. 21376165) and the Key Project of Tianjin Science and Technology Supporting Program (No. 13ZCZDNC02000).
文摘The sorption of water and organic vapors on valnemulin hydrochloride was determined by dynamic vapor sorption at 25℃. The adsorption-desorption behavior of water vapor and a series of organic vapors was investigated to probe the structural changes in valnemulin hydrochloride before and after sorption. The isothermal adsorption equilibrium data was evaluated using Guggenheim-Anderson-deBoer (GAB) and Bru- nauer-Emmett-Teller (BET) models. The BET model is applicable only at low relative pressures (0.1 ≤ RP ≤ 0.4) while the GAB model is applicable in the whole range of RPs (0.1 ≤RP≤0.9). The sorption kinetics at high RPs was determined by fitting the sorption data to the Avrami equation and the sorption content vs. time relationship could be predicted by the Avrami equation. Finally, the possible sorption mechanism of valnemulin hydrochloride was also discussed.
基金supported by the National Natural Science Foundation of China(Nos.21377150 and 51578530)
文摘Municipal wastewater reclamation is becoming of increasing importance in the world to solve the problem of water scarcity. A better understanding of the molecular composition of effluent organic matter(Ef OM) in the treated effluents of municipal wastewater treatment plants(WWTPs) is crucial for ensuring the safety of water reuse. In this study, the molecular composition of Ef OM in the secondary effluent of a WWTP in Beijing and the reclaimed water further treated with a coagulation–sedimentation–ozonation process were characterized using a non-target Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS) method and compared to that of natural organic matter(NOM) in the local source water from a reservoir. It was found that the molecular composition of Ef OM in the secondary effluent and reclaimed water was dominated by CHOS formulas, while NOM in the source water was dominated by CHO formulas. The CHO formulas of the three samples had similar origins. Anthropogenic surfactants were responsible for the CHOS formulas in Ef OM of the secondary effluent and were not well removed by the coagulation-sedimentation-ozonation treatment process adopted.
基金supported by the National Natural Science Foundation of China (Nos. 41222005, 41330744, 413301335)the Natural Science Foundation of Jiangsu Province (Nos. BK2010611, SBK201220477)+1 种基金Research Fund of State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences (Y412201404)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Biological soil disinfestation is an effective method to control soil-borne disease by flooding and incorporating with organic amendments, but field conditions and resources sometimes limited its practical application. A laboratory experiment was conducted to develop practice guidelines on controlling Fusarium wilt, a widespread banana disease caused by Fusarium oxysporum f. sp. cubense(FOC). FOC infested soil incorporated with rice or maize straw at rates of 1.5 tons/ha and 3.0 tons/ha was incubated under flooded or water-saturated(100% water holding capacity) conditions at 30℃ for 30 days. Results showed that FOC populations in the soils incorporated with either rice or maize straw rapidly reduced more than 90% in the first 15 days and then fluctuated till the end of incubation, while flooding alone without organic amendment reduced FOC populations slightly. The rapid and dramatic decrease of redox potential(down to- 350 m V) in straw-amended treatments implied that both anaerobic condition and strongly reductive soil condition would contribute to pathogen inactivation. Water-saturation combined with straw amendments had the comparable effects on reduction of FOC, indicating that flooding was not indispensable for inactivating FOC. There was no significant difference in the reduction of FOC observed in the straw amendments at between 1.5 and 3 tons/ha. Therefore,incorporating soil with straw(rice or maize straw) at a rate of 3.0 tons/ha under 100%water holding capacity or 1.5 tons/ha under flooding, would effectively alleviate banana Fusarium wilt caused by FOC after 15-day treating under 30℃.
基金supported by the National Natural Science Foundation of China (No. 21107039)the Science and Technology Research Project of Liaoning Provincial Education Department (Nos. L2011002, L2012006)+1 种基金the Science and Technology Plan Project of Liaoning Province (No. 2011230009)the Natural Science Foundation of Liaoning Province of China (No. 201202091)
文摘This study investigated the partitioning behavior of dissolved organic matter(DOM) in liquid and ice phases, as well as the changes in the optical properties and chlorine reactivity of DOM during the freezing processes of water. DOM was rejected from the ice phase and accumulated in the remaining liquid phase during water freezing. Moreover, the decrease in freezing temperature, as well as the increase in dissolved organic carbon(DOC)concentration of feed water, caused an increase in DOM captured in the ice phase. The ultraviolet-absorbing compounds, trihalomethane precursors, as well as fulvic acid- and humic acid-like fluorescent materials, were more liable to be to be rejected from the ice phase and were more easily retained in the unfrozen liquid phase during water freezing, as compared with organics(on average) that comprise DOC. In addition, it was also found a higher accumulation of these organics in the unfrozen liquid phase during water freezing at higher temperature. The freeze/thaw processes altered the quantity, optical properties, and chlorine reactivity of DOM. The decrease in ultraviolet light at 254 nm as well as the production of aromatic protein- and soluble microbial byproduct-like fluorescent materials in DOM due to freeze/thaw were consistently observed. On the other hand, the changes in DOC, trihalomethane formation potential, and fulvic acid- and humic acid-like fluorescence caused by freeze/thaw varied significantly between samples.
基金supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (No. XDB05010400)the National Natural Science Foundation of China (Nos. 21477134, 41175119, 21473009)
文摘The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds(WSOCs) and their effects on ammonium sulfate(AS) and sodium chloride were investigated using a hygroscopicity tandem differential mobility analyzer(HTDMA) in the relative humidity(RH) range of 5%–90%. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model(E-AIM) and Zdanovskii–Stokes–Robinson(ZSR) method. The equal mass multicomponent WSOCs mixture containing levoglucosan, succinic acid, phthalic acid and humic acid showed gradual water uptake without obvious phase change over the whole RH range. It was found that the organic content played an important role in the water uptake of mixed particles.When organic content was dominant in the mixture(75%), the measured hygroscopic growth was higher than predictions from the E-AIM or ZSR relation, especially under high RH conditions. For mass fractions of organics not larger than 50%, the hygroscopic growth of mixtures was in good agreement with model predictions. The influence of interactions between inorganic and organic components on the hygroscopicity of mixed particles was related to the salt type and organic content. These results could contribute to understanding of the hygroscopic behaviors of multicomponent aerosol particles.
基金supported by the Environment Research and Technology Development Fund (S-8) of the Ministry of the Environment, Japan, Grant-inAid for Scientific Research (#22404012) by JSPSthe CREST Project Fund by JST
文摘Anion exchange resins (AERs) with different properties were evaluated for their ability to remove dissolved organic matter (DOM) and bromide, and to reduce disinfection by-product (DBP) formation potentials of water collected from a eutrophic surface water source in Japan. DOM and bromide were simultaneously removed by all selected AERs in batch adsorption experiments. A polyacrylic magnetic ion exchange resin (MIEX) showed faster dissolved organic carbon (DOC) removal than other AERs because it had the smallest resin bead size. Aromatic DOM fractions with molecular weight larger than 1600 Da and fluorescent organic fractions of fulvic acid- and humic acid-like compounds were efficiently removed by all AERs. Polystyrene AERs were more effective in bromide removal than polyacrylic AERs. This result implied that the properties of AERs, i.e. material and resin size, influenced not only DOM removal but also bromide removal efficiency, MIEX showed significant chlorinated DBP removal because it had the highest DOC removal within 30 rain, whereas polystyrene AERs efficiently removed brominated DBPs, especially brominated trihalomethane species. The results suggested that, depending on source water DOM and bromide concentration, selecting a suitable AER is a key factor in effective control of chlorinated and brominated DBPs in drinking water.
文摘The nanotechnology industry advances rapidly,and at the vanguard are the promising silver nanoparticles(Ag NPs),which have diverse applications.These nanometer-sized particles have been shown to inhibit the ability of bacteria to produce adenosine triphosphate(ATP),a molecule necessary for chemical energy transport in cells.The antimicrobial properties of Ag NPs(and Ag+)make them valued antibacterial
文摘Environmental water samples can be extremely complex,with potentially thousands of molecules that can derive from natural organic matter(NOM)and thousands that derive from anthropogenic contaminants.As complex as these samples are,drinking water can be even more complex.Due to disinfectants that are used to treat drinking water(e.g.,chlorine,chloramines,
基金supported by the public welfare projects from MEPPRC (No. 201409010)
文摘PM(2.5) samples were collected in Zhengzhou during 3 years of observation, and chemical characteristics and source contribution were analyzed. Approximately 96% of the daily PM(2.5) concentrations and annual average values exceeded the Chinese National Ambient Air Quality Daily and Annual Standards, indicating serious PM(2.5) pollution. The average concentration of water-soluble inorganic ions was 2.4 times higher in heavily polluted days(daily PM32.5 concentrations > 250 μg/mand visibility < 3 km) than that in other days, with sulfate, nitrate, and ammonium as major ions. According to the ratio of NO-3/SO2-4,stationary sources are still the dominant source of PM(2.5) and vehicle emission could not be ignored. The ratio of secondary organic carbon to organic carbon indicated that photochemical reactivity in heavily polluted days was more intense than in other days.Crustal elements were the most abundant elements, accounting for more than 60% of 23 elements. Chemical Mass Balance results indicated that the contributions of major sources(i.e., nitrate, sulfate, biomass, carbon and refractory material, coal combustion, soil dust,vehicle, and industry) of PM(2.5) were 13%, 16%, 12%, 2%, 14%, 8%, 7%, and 8% in heavily polluted days and 20%, 18%, 9%, 2%, 27%, 14%, 15%, and 9% in other days, respectively.Extensive combustion activities were the main sources of polycyclic aromatic hydrocarbons during the episode(Jan 1-9, 2015) and the total benzo[a]pyrene equivalency concentrations in heavily polluted days present significant health threat. Because of the effect of regional transport, the pollution level of PM(2.5) in the study area was aggravated.
基金supported by the National Natural Science Foundation of China(51502012,21676020,and 21620102007)Beijing Natural Science Foundation(2162032)+3 种基金the Start-up Fund for Talent Introduction of Beijing University of Chemical Technology(BUCT),Talent Cultivation of State Key Laboratory of Organic-Inorganic Compositesthe Fundamental Research Funds for the Central Universities(buctrc201420,buctrc201714,and ZD1502)the ‘‘111" project of China(B14004)Distinguished Scientist Program at BUCT(buctylkxj02)
文摘TiO2 has been everlastingly employed as popular photocatalyst for water splitting. However, the wide band gap (3.0-3.2 eV) and poor absorption to visible light of TiO2 result in a low utilization of solar energy and limit its large-scale application. To decrease its band gap and promote the utilization of full solar energy, we here modified TiO2 by in situ growth of N-rich covalent organic polymer (termed as COPuM). During the in situ growth of COPuM on the surface of TiO2, intimate contacts between TiO2 and COPuM were built and core-shell structures were finally formed. The derived TiO2@COPHM demon-strated a narrower band gap (2.53 eV) compared to raw TiO2 (3.13 eV) and improved absorption to visible light. The optimal TiO2@COPHM hybrid exhibited excellent hydrogen evolution performance of 162.7μmol h^-1 under simulated sunlight which was more than 3 times higher than raw TiO2 (51.3μmol h^-1). Particularly, visible light hydrogen evolution rate of TiO2@COPHM reached 0.65 μmol h^-1 while non-hydrogen generation was observed using raw TiO2.
基金financially supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Nos.KZCX2-YW-453,KZCX2-YW-JS404,and KZCX2-EW-408)the National Natural Science Foundation of China(No.41005082)the Commonweal Program of Environment Protection Department of China(No.201009004)
文摘Atmospheric fine particles (PM2.5) were collected in this study with middle volume samplers in Fuzhou, China, during both normal days and haze days in summer (September 2007) and winter (january 2008). The concentrations, distributions, and sources of polycyclic aromatic hydrocarbons (PAHs), organic carbon (OC), elemental carbon (EC), and water soluble inorganic ions (WSIls) were determinated. The results showed that the concentrations of PM2.s, PAHs, OC, EC, and WSIIs were in the orders of haze 〉 normal and winter〉 summer. The dominant PAHs of PM2.s in Fuzhou were Fluo, Pyr, Chr, BbF, BkF, BaP, BghiP, and IcdP, which represented about 80.0% of the total PAHs during different sampling periods. The BaPeq concentrations of ^-~PAHs were 0.78, 0.99, 1.22, and 2.43 ng/m3 in summer normal, summer haze, winter normal, and winter haze, respectively. Secondary pollutants (SO42 , NO3 , NH4*, and OC) were the major chemical compositions of PM2.5, accounting for 69.0%, 55.1%, 63.4%, and 64.9% of PM2.s mass in summer normal, summer haze, winter normal, and winter haze, respectively. Correspondingly, secondary organic carbon (SOC) in Fuzhou accounted for 20.1%, 48.6%, 24.5%, and 50.5% of OC. The average values of nitrogen oxidation ratio (NOR) and sulfur oxidation ratio (SOR) were higher in haze days (0.08 and 0.27) than in normal days (0.05 and 0.22). Higher OC/EC ratios were also found in haze days (5.0) than in normal days (3.3). Correlation analysis demonstrated that visibility had positive correlations with wind speed, and neg- ative correlations with relative humidity and major air pollutants. Overall, the enrichments of PM2.5, OC, EC, SO42 ,andNO3 promoted haze formation. Furthermore, the diagnostic ratios of IcdP/(IcdP + BghiP), lcdP/BghiP, OC/EC, and NO3 /SO42 indicated that vehicle exhaust and coal consumption were the main sources of pollutants in Fuzhou.