Simulated photo-degradation of fluorescent dissolved organic matter(FDOM) in Lake Baihua(BH) and Lake Hongfeng(HF) was investigated with three-dimensional excitationemission matrix(3 DEEM) fluorescence combined with t...Simulated photo-degradation of fluorescent dissolved organic matter(FDOM) in Lake Baihua(BH) and Lake Hongfeng(HF) was investigated with three-dimensional excitationemission matrix(3 DEEM) fluorescence combined with the fluorescence regional integration(FRI),parallel factor(PARAFAC) analysis,and multi-order kinetic models.In the FRI analysis,fulvic-like and humic-like materials were the main constituents for both BH-FDOM and HF-FDOM.Four individual components were identified by use of PARAFAC analysis as humic-like components(C1),fulvic-like components(C2),protein-like components(C3) and unidentified components(C4).The maximum 3 DEEM fluorescence intensity of PARAFAC components C1-C3 decreased by about 60%,70% and 90%,respectively after photo-degradation.The multi-order kinetic model was acceptable to represent the photo-degradation of FDOM with correlation coefficient(Radj2)(0.963-0.998).The photo-degradation rate constants(kn) showed differences of three orders of magnitude,from 1.09 × 10-6 to 4.02 × 10-4 min-1,and half-life of multi-order model(T1/2n)ranged from 5.26 to 64.01 min.The decreased values of fluorescence index(FI) and biogenic index(BI),the fact that of percent fluorescence response parameter of Region I(PⅠ,n) showed the greatest change ratio,followed by percent fluorescence response parameter of Region II(PⅡ,n,while the largest decrease ratio was found for C3 components,and the lowest T1/2n was observed for C3,indicated preferential degradation of protein-like materials/components derived from biological sources during photodegradation.This research on the degradation of FDOM by 3 DEEM/FRI-PARAFAC would be beneficial to understanding the photo-degradation of FD OM in natural environments and accurately predicting the environmental behaviors of contaminants in the presence of FDOM.展开更多
The Southern Ocean is an important carbon sink pool and plays a critical role in the global carbon cycling.The Amundsen Sea was reported to be highly productive in inshore area in the Southern Ocean.In order to invest...The Southern Ocean is an important carbon sink pool and plays a critical role in the global carbon cycling.The Amundsen Sea was reported to be highly productive in inshore area in the Southern Ocean.In order to investigate the influence of transparent exopolymer particles(TEP)on the behavior of dissolved organic carbon(DOC)in this region,a comprehensive study was conducted,encompassing both open water areas and highly productive polynyas.It was found that microbial heterotrophic metabolism is the primary process responsible for the production of humic-like fluorescent components in the open ocean.The relationship between apparent oxygen utilization and the two humic-like components can be accurately described by a power-law function,with a conversion rate consistent with that observed globally.The presence of TEP was found to have little impact on this process.Additionally,the study revealed the accumulation of DOC at the sea surface in the Amundsen Sea Polynya,suggesting that TEP may play a critical role in this phenomenon.These findings contribute to a deeper understanding of the dynamics and surface accumulation of DOC in the Amundsen Sea Polynya,and provide valuable insights into the carbon cycle in this region.展开更多
Dissolved organic matter(DOM)plays a crucial role in both the carbon cycle and geochemical cycles of other nutrient elements,which is of importance to the management and protection of the aquatic environments.To achie...Dissolved organic matter(DOM)plays a crucial role in both the carbon cycle and geochemical cycles of other nutrient elements,which is of importance to the management and protection of the aquatic environments.To achieve a more comprehensive understanding the characteristics of DOM in the Changjiang(Yangtze)River basin,water samples from four natural lakes(Xiandao,Baoan,Daye,and Qingshan)in southeastern Hubei Province in China with different eutrophication levels were collected and analyzed.The optical characteristics were analyzed using ultraviolet-visible spectrophotometry and excitation-emission matrix spectroscopy coupled with parallel factor analysis.The results show that:(1)two humic-like components(C1 and C2)and two protein-like substances(C3 and C4)of DOM were identified in all waterbodies;(2)C3 originated primarily from the degradation of microalgae and contributed substantially to humic-like components during transformation.C4 was widely present in the Changjiang River basin and its formation was related to microbial activity,rather than algal blooms or seasons.Influenced by the water mixing,the protein-like components were more likely to be transformed by microorganism,whereas humic-like components were more easily to be photobleached;(3)the concentration of DOM and the fluorescence intensity of humic-like components gradually increased with rising lake eutrophication levels.With respect to protein-like components,only C3 showed changes along the eutrophication gradients;(4)DOM showed a high affinity with permanganate index(COD Mn)and chlorophyll a(chl a)while the relationship was variable with phosphorus.This study helps us systematically understand the DOM characteristics,microbial activities,and pollutant transformation in the Changjiang River basin and provides reference to the ecological restoration of aquatic environments.展开更多
Dissolved organic matter(DOM)plays a vital role in promoting carbon and nutrient cycling.It is a food source for organisms and controls the migration and transformation of trace metals and other contaminants in aquati...Dissolved organic matter(DOM)plays a vital role in promoting carbon and nutrient cycling.It is a food source for organisms and controls the migration and transformation of trace metals and other contaminants in aquatic systems.The contributions of aquatic DOM to the environment and ecology of a system are closely related to its abundance and chemical structure.In this study,the chemical composition and binding properties of DOM in a hypersaline lake watershed were investigated for the fi rst time using dissolved organic carbon(DOC)analysis,absorption spectroscopy,Fourier transform infrared spectroscopy,pyrolysis-GC-MS(Py-GC-MS),and fl uorescence parallel factor(PARAFAC)analysis combined with Pb(II)titration techniques.The results showed that DOM from the tributaries that fl owed into the lake had a lower DOC content,higher molecular weight,and higher specifi c UV absorbance than the DOM in lake water.Protein-like fl uorophores were mainly found in tributary and lake surface water DOM(LSDOM)and humic-like substances were abundant in lake groundwater DOM(LGDOM).Using this multi-methodological approach,we found that the DOM from the hypersaline lake watershed was mainly from microbial origins,and consisted of aromatics,carbohydrates,and aliphatics.The results from quantitative analysis showed that DOM from the infl owing tributaries contained more aromatics,lower carbohydrates,and lower aliphatics than DOM in the lake.Monocyclic aromatic hydrocarbons and carbohydrates were more abundant in LSDOM than LGDOM.The results from the Pb(II)titration technique coupled with PARAFAC analysis suggested that PARAFAC-derived components had relatively low condition stability constants(log K_(M)<2).Of the two types of lake DOM,the LGDOM had a higher Pb(II)binding potential than the LSDOM.From this study we have improved our understanding of how DOM within a hypersaline lake watershed varies in its composition and potential to bind with metals.展开更多
Chromophoric dissolved organic matter(CDOM)is a key component of organic matter that contributes to the ecological functioning of lakes.The lakes in Taihu Lake Basin play an important role in maintaining regional ecol...Chromophoric dissolved organic matter(CDOM)is a key component of organic matter that contributes to the ecological functioning of lakes.The lakes in Taihu Lake Basin play an important role in maintaining regional ecological stabilities;however,the optical characteristics of the CDOM in the upstream and downstream lakes in this basin have not yet been systematically studied.Here,the optical characteristics of CDOM in ten lakes of upstream and downstream of the Taihu Lake Basin were studied using UV-Visible and excitation-emission matrix spectroscopies.Three different fluorophores consisting of two humic-like components(C1,C2)and one protein-like component(C3)were identified by parallel factor analysis.Soil or surface erosion was responsible for the higher abund-ance of C1 in the upstream lakes,and increased biological activities accounted for the higher abundance of C3 in the downstream lakes.Rainfall erosion in the wet season led to an increase in CDOM.We also found that the photodegradation and flocculation degree,which played a significant role in reducing CDOM,were higher in downstream lakes than in upstream lakes.Optical analysis of CDOM provides a promising method for monitoring water qualities(e.g.,total phosphorus and potassium permanganate index)in each lake.Re-ductions in soil or surface erosion in the upstream are needed to improve water quality.展开更多
A metalloporphyrin-based fluorescent sensor was developed to determine the acid value in frying oil.The electronic and structural performances of iron tetraphenylporphyrin(FeTPP)were theoretically investigated using t...A metalloporphyrin-based fluorescent sensor was developed to determine the acid value in frying oil.The electronic and structural performances of iron tetraphenylporphyrin(FeTPP)were theoretically investigated using time-dependent density functional theory and density functional theory at the B3LYP/LANL2DZ level.The quantified FeTPP-based fluorescent sensor results revealed its excellent performance in discriminating different analytes.In the present work,the acid value of palm olein was determined after every single frying cycle.A total of 10 frying cycles were conducted each day for 10 consecutive days.The FeTPP-based fluorescent sensor was used to quantify the acid value,and the results were compared with the chemical data obtained by conventional titration method.The synchronous fluorescence spectrum for each sample was recorded.Parallel factor analysis was used to decompose the three-dimensional spectrum data.Then,the support vector regression(SVR),partial least squares,and back-propagation artificial neural network methods were applied to build the regression models.After the comparison of the constructed models,the SVR models exhibited the highest correlation coefficients among all models,with 0.9748 and 0.9276 for the training and test sets,respectively.The findings suggested the potential of FeTPP-based fluorescent sensor in rapid monitoring of frying oil quality and perhaps also in other foods with higher oil contents.展开更多
This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced ...This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced oxidation processes (AOPs).The changing characteristics of NOM were evaluated by dissolved organic carbon (DOC),the specific UV absorbance (SUVA),trihalomethanes formation potential (THMFP),organic halogen adsorbable on activated carbon formation potential (AOXFP) and parallel factor analysis of excitation–emission matrices (PARAFAC-EEMs).In the three UV-based AOPs,HPI fraction with low molecular weight and aromaticity was more likely to degradate than HPO and TPI,and the removal efficiency of SUVA for HPO was much higher than TPI and HPI fraction.In terms of the specific THMFP of HPO,TPI and HPI,a reduction was achieved in the UV/H_(2)O_(2)process,and the higest removal rate even reached to 83%.UV/TiO_(2)and UV/PS processes can only decrease the specific THMFP of HPI.The specific AOXFP of HPO,TPI and HPI fractions were all able to be degraded by the three UV-based AOPs,and HPO content is more susceptible to decompose than TPI and HPI content.UV/H_(2)O_(2)was found to be the most effective treatment for the removal of THMFP and AOXFP under given conditions.C1 (microbial or marine derived humic-like substances),C_(2) (terrestrially derived humic-like substances)and C_(3) (tryptophan-like proteins) fluorescent components of HPO fraction were fairly labile across the UV-based AOPs treatment.C_(3) of each fraction of NOM was the most resistant to degrade upon the UV-based AOPs.Results from this study may provide the prediction about the consequence of UV-based AOPs for the degradation of different fractions of NOM with varied characteristics.展开更多
Sulfadiazine(SD)is a common antibiotic administered to treat bacterial infections in livestock,and its fate andmigration are greatly affected by dissolved organicmatter(DOM).The soil infiltration system[a typical low-...Sulfadiazine(SD)is a common antibiotic administered to treat bacterial infections in livestock,and its fate andmigration are greatly affected by dissolved organicmatter(DOM).The soil infiltration system[a typical low-impact development(LID)facility]can significantly alterDOMproperties during runoff pollution,thus affecting the complexation of SDwithDOM.Here,the binding characteristics of different DOM components and SD in the soil infiltration system were explored using spectroscopic techniques(excitation–emission matrices,parallel factor analysis,and synchronous fluorescence spectroscopy).Combined with the weakening of DOM fluorescence intensity and 78.63%reduction in mean SD concentration following treatment,synchronous degradation may have occurred.The binding sequence of SD and DOM fluorophores was further explored using two-dimensional correlation spectroscopy.Effluent DOM showed greater sensitivity to SD and more binding sites than influent DOM.Moreover,hydrophobic protein-like substances exhibited higher log K_(M) values than other fluorescent components,indicating that protein-like components play significant roles in SD complexation.The soil percolation system improved the complexation stability and binding sequence of fulvic-like substances.Thus,SD–DOM can be intercepted and degraded using LID facilities to reduce the risk of SD in aquatic environments.展开更多
Dissolved organic matter(DOM)in rivers is a critical regulator of the cycling and toxicity of pollutants and the behavior of DOM is a key indicator for the health of the environment.We investigated the sources and cha...Dissolved organic matter(DOM)in rivers is a critical regulator of the cycling and toxicity of pollutants and the behavior of DOM is a key indicator for the health of the environment.We investigated the sources and characteristics of DOM in surface water and sediment samples of the Wei River,China.Dissolved organic carbon(DOC)concentration and ultraviolet absorbance at 254 nm(UV254)increased in the surface water and were decreased in the sediment downstream,indicating that the source of DOM in the water differed from the sediment.Parallel factor(PARAFAC)analysis of the excitation-emission matrices(EEM)revealed the presence of terrestrial humus-like,microbial humus-like and tryptophan-like proteins in the surface water,whereas the sediment contained UVA humic-like,UVC humic-like and fulvic-like in the sediment.The DOM in the surface water and sediment were mainly derived from microbial metabolic activity and the surrounding soil.Surface water DOM displayed greater photodegradation potential than sediment DOM.PARAFAC analysis indicated that the terrestrial humic-like substance in the water and the fulvic-like component in the sediment decomposed more rapidly.These data describe the characteristics of DOM in the Wei River and are crucial to understanding the fluctuations in environmental patterns.展开更多
This work was to study composition characteristics and the subsequent effect on the lead(Pb) binding properties of dissolved organic matter(DOM) derived from seaweed-based(SWOF) and chicken manure organic fertilizers(...This work was to study composition characteristics and the subsequent effect on the lead(Pb) binding properties of dissolved organic matter(DOM) derived from seaweed-based(SWOF) and chicken manure organic fertilizers(CMOF) during a one-year field incubation experiment using the excitation-emission matrix-parallel factor(EEM-PARAFAC) and twodimensional correlation spectroscopy(2DCOS) analysis. Results showed that high aromatic and hydrophobic fluorescent substances were enriched in CMOF-derived DOM and SWOFderived DOM and enhanced over time. And phenolic groups in the fulvic-like substances for SWOF-derived DOM and carboxyl groups in the humic-like substances for CMOF-derived DOM had the fastest responses over time, respectively. Moreover, both non-fluorescent polysaccharides and fluorescent humic-like substances or fulvic-like substances with aromatic(C=C) groups first participated in the binding process of Pb to SWOF-derived DOM on day 0 and 180 during the lead binding process. In contrast, humic-like substances associated with aromatic(C=C) and phenolic groups gave a faster response to Pb binding on day 360. Regarding CMOF-derived DOM, the fulvic-like substances associated with aromatic(C=C) and carboxylic groups displayed a faster response to Pb ions on day 0. Nonetheless,polysaccharides and humic-like associated with phenolic groups had a faster response on days 180 and 360. It is noteworthy that the polysaccharides, which participated in Pb binding to CMOF-derived DOM, posed a higher risk of Pb in the environment after 360 days. Therefore, these findings gave new insights into the long-term applications of commercial organic fertilizers for the amendment of soil.展开更多
This study established back-propagation neural networks(BPNNs)for evaluating the freshness of bighead carp(Hypophthalmichthys nobilis)heads during chilled storage via fluorescence spectroscopy using an excitation-emis...This study established back-propagation neural networks(BPNNs)for evaluating the freshness of bighead carp(Hypophthalmichthys nobilis)heads during chilled storage via fluorescence spectroscopy using an excitation-emission matrix(EEM).The total volatile basic nitrogen(TVB-N)and total aerobic count(TAC)of fish increased obviously during storage at 0,4,8,12,and 16°C,while sensory scores decreased with increasing storage time.The EEM fluorescence intensity was measured,and its change was correlated with the freshness indicators of the samples.Three characteristic components of EEM data were extracted by parallel factor analysis,and two freshness indicators were used to construct the EEM-BPNNs model.The results demonstrated that the relative errors of the EEM-BPNNs model for TVB-N and TAC were less than 14%.This result indicated that the EEM-BPNNs model could determine the freshness of fish in cold chains in a rapid and nondestructive way.展开更多
The presence of municipal wastewater at the intake of a major drinking water treatment facility located on Lake Ontario was examined using fluorescence data collected during a period of continuous monitoring.In additi...The presence of municipal wastewater at the intake of a major drinking water treatment facility located on Lake Ontario was examined using fluorescence data collected during a period of continuous monitoring.In addition,controlled mixing of lake water and wastewater sampled from a local treatment facility were conducted using a bench-scale fluorescence system to quantify observed changes in natural organic matter.Multivariate linear regression was applied to components derived from parallel factors analysis.The resulting mean absolute error for predicted wastewater level was 0.22%(V/V,wastewater/lake water),indicating that wastewater detection at below 1.0%(V/V)was possible.Analyses of sucralose,a wastewater indicator,were conducted for treated wastewater as well as surface water collected at two intake locations on Lake Ontario.Results suggested minimal wastewater contribution at the drinking water intake.A wastewater detection model using a moving baseline was developed and applied to continuous fluorescence data collected at one of the drinking water intakes,which agreed well with sucralose results.Furthermore,the simulated addition of 1.0%(V/V)of wastewater/wastewater was detectable in 89%of samples analyzed,demonstrating the utility of fluorescence-based wastewater monitoring.展开更多
基金financially supported by the National Natural Science Foundation of China(No.41573130)BNU Interdisciplinary Research Foundation for First-Year Doctoral Candidates(No.BNUXKJC1802)
文摘Simulated photo-degradation of fluorescent dissolved organic matter(FDOM) in Lake Baihua(BH) and Lake Hongfeng(HF) was investigated with three-dimensional excitationemission matrix(3 DEEM) fluorescence combined with the fluorescence regional integration(FRI),parallel factor(PARAFAC) analysis,and multi-order kinetic models.In the FRI analysis,fulvic-like and humic-like materials were the main constituents for both BH-FDOM and HF-FDOM.Four individual components were identified by use of PARAFAC analysis as humic-like components(C1),fulvic-like components(C2),protein-like components(C3) and unidentified components(C4).The maximum 3 DEEM fluorescence intensity of PARAFAC components C1-C3 decreased by about 60%,70% and 90%,respectively after photo-degradation.The multi-order kinetic model was acceptable to represent the photo-degradation of FDOM with correlation coefficient(Radj2)(0.963-0.998).The photo-degradation rate constants(kn) showed differences of three orders of magnitude,from 1.09 × 10-6 to 4.02 × 10-4 min-1,and half-life of multi-order model(T1/2n)ranged from 5.26 to 64.01 min.The decreased values of fluorescence index(FI) and biogenic index(BI),the fact that of percent fluorescence response parameter of Region I(PⅠ,n) showed the greatest change ratio,followed by percent fluorescence response parameter of Region II(PⅡ,n,while the largest decrease ratio was found for C3 components,and the lowest T1/2n was observed for C3,indicated preferential degradation of protein-like materials/components derived from biological sources during photodegradation.This research on the degradation of FDOM by 3 DEEM/FRI-PARAFAC would be beneficial to understanding the photo-degradation of FD OM in natural environments and accurately predicting the environmental behaviors of contaminants in the presence of FDOM.
基金funded by the National Natural Science Foundation of China(Grant nos.42276255 and 41976227)project“Impact and Response of Antarctic Seas to Climate Change,IRASCC 2020-2022”(Grant nos.01-01-02A and 02-02-05).
文摘The Southern Ocean is an important carbon sink pool and plays a critical role in the global carbon cycling.The Amundsen Sea was reported to be highly productive in inshore area in the Southern Ocean.In order to investigate the influence of transparent exopolymer particles(TEP)on the behavior of dissolved organic carbon(DOC)in this region,a comprehensive study was conducted,encompassing both open water areas and highly productive polynyas.It was found that microbial heterotrophic metabolism is the primary process responsible for the production of humic-like fluorescent components in the open ocean.The relationship between apparent oxygen utilization and the two humic-like components can be accurately described by a power-law function,with a conversion rate consistent with that observed globally.The presence of TEP was found to have little impact on this process.Additionally,the study revealed the accumulation of DOC at the sea surface in the Amundsen Sea Polynya,suggesting that TEP may play a critical role in this phenomenon.These findings contribute to a deeper understanding of the dynamics and surface accumulation of DOC in the Amundsen Sea Polynya,and provide valuable insights into the carbon cycle in this region.
基金Supported by the Science and Technology Research Project of Education Department of Hubei Province(Nos.Q20182502,D20152503)the Innovation Team Project of HBNU of Heavy Metal Pollution Mechanism and Ecological Restoration for Lake-Catchment System,Youth Project of Hubei Natural Science Foundation(No.2018CFB321)the Hubei Undergraduate Training Program for Innovation and Entrepreneurship(No.S201910513001)。
文摘Dissolved organic matter(DOM)plays a crucial role in both the carbon cycle and geochemical cycles of other nutrient elements,which is of importance to the management and protection of the aquatic environments.To achieve a more comprehensive understanding the characteristics of DOM in the Changjiang(Yangtze)River basin,water samples from four natural lakes(Xiandao,Baoan,Daye,and Qingshan)in southeastern Hubei Province in China with different eutrophication levels were collected and analyzed.The optical characteristics were analyzed using ultraviolet-visible spectrophotometry and excitation-emission matrix spectroscopy coupled with parallel factor analysis.The results show that:(1)two humic-like components(C1 and C2)and two protein-like substances(C3 and C4)of DOM were identified in all waterbodies;(2)C3 originated primarily from the degradation of microalgae and contributed substantially to humic-like components during transformation.C4 was widely present in the Changjiang River basin and its formation was related to microbial activity,rather than algal blooms or seasons.Influenced by the water mixing,the protein-like components were more likely to be transformed by microorganism,whereas humic-like components were more easily to be photobleached;(3)the concentration of DOM and the fluorescence intensity of humic-like components gradually increased with rising lake eutrophication levels.With respect to protein-like components,only C3 showed changes along the eutrophication gradients;(4)DOM showed a high affinity with permanganate index(COD Mn)and chlorophyll a(chl a)while the relationship was variable with phosphorus.This study helps us systematically understand the DOM characteristics,microbial activities,and pollutant transformation in the Changjiang River basin and provides reference to the ecological restoration of aquatic environments.
基金Supported by the Natural Science Foundation of Qinghai Province(Nos.2020-ZJ-940Q,2014-ZJ-937Q)the West Light Foundation of the Chinese Academy of Sciences(No.E010GC09)the Youth Innovation Promotion Association CAS(No.E010GC15)。
文摘Dissolved organic matter(DOM)plays a vital role in promoting carbon and nutrient cycling.It is a food source for organisms and controls the migration and transformation of trace metals and other contaminants in aquatic systems.The contributions of aquatic DOM to the environment and ecology of a system are closely related to its abundance and chemical structure.In this study,the chemical composition and binding properties of DOM in a hypersaline lake watershed were investigated for the fi rst time using dissolved organic carbon(DOC)analysis,absorption spectroscopy,Fourier transform infrared spectroscopy,pyrolysis-GC-MS(Py-GC-MS),and fl uorescence parallel factor(PARAFAC)analysis combined with Pb(II)titration techniques.The results showed that DOM from the tributaries that fl owed into the lake had a lower DOC content,higher molecular weight,and higher specifi c UV absorbance than the DOM in lake water.Protein-like fl uorophores were mainly found in tributary and lake surface water DOM(LSDOM)and humic-like substances were abundant in lake groundwater DOM(LGDOM).Using this multi-methodological approach,we found that the DOM from the hypersaline lake watershed was mainly from microbial origins,and consisted of aromatics,carbohydrates,and aliphatics.The results from quantitative analysis showed that DOM from the infl owing tributaries contained more aromatics,lower carbohydrates,and lower aliphatics than DOM in the lake.Monocyclic aromatic hydrocarbons and carbohydrates were more abundant in LSDOM than LGDOM.The results from the Pb(II)titration technique coupled with PARAFAC analysis suggested that PARAFAC-derived components had relatively low condition stability constants(log K_(M)<2).Of the two types of lake DOM,the LGDOM had a higher Pb(II)binding potential than the LSDOM.From this study we have improved our understanding of how DOM within a hypersaline lake watershed varies in its composition and potential to bind with metals.
基金Under the auspices of the Science and Technology Research Project of Education Department of Hubei Province(No.Q20182502,No.D20152503)Innovation Team Project of HBNU of Heavy Metal Pollution Mechanism and Ecological Restoration for Lake-Catchment System(No.2019CZ014)。
文摘Chromophoric dissolved organic matter(CDOM)is a key component of organic matter that contributes to the ecological functioning of lakes.The lakes in Taihu Lake Basin play an important role in maintaining regional ecological stabilities;however,the optical characteristics of the CDOM in the upstream and downstream lakes in this basin have not yet been systematically studied.Here,the optical characteristics of CDOM in ten lakes of upstream and downstream of the Taihu Lake Basin were studied using UV-Visible and excitation-emission matrix spectroscopies.Three different fluorophores consisting of two humic-like components(C1,C2)and one protein-like component(C3)were identified by parallel factor analysis.Soil or surface erosion was responsible for the higher abund-ance of C1 in the upstream lakes,and increased biological activities accounted for the higher abundance of C3 in the downstream lakes.Rainfall erosion in the wet season led to an increase in CDOM.We also found that the photodegradation and flocculation degree,which played a significant role in reducing CDOM,were higher in downstream lakes than in upstream lakes.Optical analysis of CDOM provides a promising method for monitoring water qualities(e.g.,total phosphorus and potassium permanganate index)in each lake.Re-ductions in soil or surface erosion in the upstream are needed to improve water quality.
基金sponsored by the National Natural Science Foundation of China(No.31701685)Educational Commission of Anhui Province(KJ2021A1071)Chuzhou Municipal Science and Technology(Nos.2021GJ011,2021ZD017),China.
文摘A metalloporphyrin-based fluorescent sensor was developed to determine the acid value in frying oil.The electronic and structural performances of iron tetraphenylporphyrin(FeTPP)were theoretically investigated using time-dependent density functional theory and density functional theory at the B3LYP/LANL2DZ level.The quantified FeTPP-based fluorescent sensor results revealed its excellent performance in discriminating different analytes.In the present work,the acid value of palm olein was determined after every single frying cycle.A total of 10 frying cycles were conducted each day for 10 consecutive days.The FeTPP-based fluorescent sensor was used to quantify the acid value,and the results were compared with the chemical data obtained by conventional titration method.The synchronous fluorescence spectrum for each sample was recorded.Parallel factor analysis was used to decompose the three-dimensional spectrum data.Then,the support vector regression(SVR),partial least squares,and back-propagation artificial neural network methods were applied to build the regression models.After the comparison of the constructed models,the SVR models exhibited the highest correlation coefficients among all models,with 0.9748 and 0.9276 for the training and test sets,respectively.The findings suggested the potential of FeTPP-based fluorescent sensor in rapid monitoring of frying oil quality and perhaps also in other foods with higher oil contents.
基金supported by the “Central leading local” Science and Technology Development Fund Project of Shandong Province (No.YDZX202037 00001642)the Key Research and Development Plan of Shandong Province(NO.2020CXGC011406),the Natural Science Foundation of Shandong Province (No.ZR2021ME166)the Special Project of Taishan Scholar Construction Engineering (No.ts201712084)。
文摘This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced oxidation processes (AOPs).The changing characteristics of NOM were evaluated by dissolved organic carbon (DOC),the specific UV absorbance (SUVA),trihalomethanes formation potential (THMFP),organic halogen adsorbable on activated carbon formation potential (AOXFP) and parallel factor analysis of excitation–emission matrices (PARAFAC-EEMs).In the three UV-based AOPs,HPI fraction with low molecular weight and aromaticity was more likely to degradate than HPO and TPI,and the removal efficiency of SUVA for HPO was much higher than TPI and HPI fraction.In terms of the specific THMFP of HPO,TPI and HPI,a reduction was achieved in the UV/H_(2)O_(2)process,and the higest removal rate even reached to 83%.UV/TiO_(2)and UV/PS processes can only decrease the specific THMFP of HPI.The specific AOXFP of HPO,TPI and HPI fractions were all able to be degraded by the three UV-based AOPs,and HPO content is more susceptible to decompose than TPI and HPI content.UV/H_(2)O_(2)was found to be the most effective treatment for the removal of THMFP and AOXFP under given conditions.C1 (microbial or marine derived humic-like substances),C_(2) (terrestrially derived humic-like substances)and C_(3) (tryptophan-like proteins) fluorescent components of HPO fraction were fairly labile across the UV-based AOPs treatment.C_(3) of each fraction of NOM was the most resistant to degrade upon the UV-based AOPs.Results from this study may provide the prediction about the consequence of UV-based AOPs for the degradation of different fractions of NOM with varied characteristics.
基金supported by the National Water Pollution Control and Management Technology Major Project(No.2018ZX07110005)the National Natural Science Foundation of China(No.52170097)+1 种基金the Fundamental Research Funds for Beijing University of Civil Engineering and Architecture(No.X20137)BUCEA Post Graduate Innovation Project(No.2022).
文摘Sulfadiazine(SD)is a common antibiotic administered to treat bacterial infections in livestock,and its fate andmigration are greatly affected by dissolved organicmatter(DOM).The soil infiltration system[a typical low-impact development(LID)facility]can significantly alterDOMproperties during runoff pollution,thus affecting the complexation of SDwithDOM.Here,the binding characteristics of different DOM components and SD in the soil infiltration system were explored using spectroscopic techniques(excitation–emission matrices,parallel factor analysis,and synchronous fluorescence spectroscopy).Combined with the weakening of DOM fluorescence intensity and 78.63%reduction in mean SD concentration following treatment,synchronous degradation may have occurred.The binding sequence of SD and DOM fluorophores was further explored using two-dimensional correlation spectroscopy.Effluent DOM showed greater sensitivity to SD and more binding sites than influent DOM.Moreover,hydrophobic protein-like substances exhibited higher log K_(M) values than other fluorescent components,indicating that protein-like components play significant roles in SD complexation.The soil percolation system improved the complexation stability and binding sequence of fulvic-like substances.Thus,SD–DOM can be intercepted and degraded using LID facilities to reduce the risk of SD in aquatic environments.
基金the National Natural Science Foundation of China(Grant No.41977307).
文摘Dissolved organic matter(DOM)in rivers is a critical regulator of the cycling and toxicity of pollutants and the behavior of DOM is a key indicator for the health of the environment.We investigated the sources and characteristics of DOM in surface water and sediment samples of the Wei River,China.Dissolved organic carbon(DOC)concentration and ultraviolet absorbance at 254 nm(UV254)increased in the surface water and were decreased in the sediment downstream,indicating that the source of DOM in the water differed from the sediment.Parallel factor(PARAFAC)analysis of the excitation-emission matrices(EEM)revealed the presence of terrestrial humus-like,microbial humus-like and tryptophan-like proteins in the surface water,whereas the sediment contained UVA humic-like,UVC humic-like and fulvic-like in the sediment.The DOM in the surface water and sediment were mainly derived from microbial metabolic activity and the surrounding soil.Surface water DOM displayed greater photodegradation potential than sediment DOM.PARAFAC analysis indicated that the terrestrial humic-like substance in the water and the fulvic-like component in the sediment decomposed more rapidly.These data describe the characteristics of DOM in the Wei River and are crucial to understanding the fluctuations in environmental patterns.
基金supported by the Natural Science Foundation for High-level Talents from Basic and Applied Basic Research Programs of Hainan Province (No. 2019RC022)the National Natural Science Foundation of China (Nos. 41807326 and 21866013)。
文摘This work was to study composition characteristics and the subsequent effect on the lead(Pb) binding properties of dissolved organic matter(DOM) derived from seaweed-based(SWOF) and chicken manure organic fertilizers(CMOF) during a one-year field incubation experiment using the excitation-emission matrix-parallel factor(EEM-PARAFAC) and twodimensional correlation spectroscopy(2DCOS) analysis. Results showed that high aromatic and hydrophobic fluorescent substances were enriched in CMOF-derived DOM and SWOFderived DOM and enhanced over time. And phenolic groups in the fulvic-like substances for SWOF-derived DOM and carboxyl groups in the humic-like substances for CMOF-derived DOM had the fastest responses over time, respectively. Moreover, both non-fluorescent polysaccharides and fluorescent humic-like substances or fulvic-like substances with aromatic(C=C) groups first participated in the binding process of Pb to SWOF-derived DOM on day 0 and 180 during the lead binding process. In contrast, humic-like substances associated with aromatic(C=C) and phenolic groups gave a faster response to Pb binding on day 360. Regarding CMOF-derived DOM, the fulvic-like substances associated with aromatic(C=C) and carboxylic groups displayed a faster response to Pb ions on day 0. Nonetheless,polysaccharides and humic-like associated with phenolic groups had a faster response on days 180 and 360. It is noteworthy that the polysaccharides, which participated in Pb binding to CMOF-derived DOM, posed a higher risk of Pb in the environment after 360 days. Therefore, these findings gave new insights into the long-term applications of commercial organic fertilizers for the amendment of soil.
基金This study was supported by the Young Beijing Scholars Program and Beijing Agricultural Forestry Academy Foundation(QNJJ202218).
文摘This study established back-propagation neural networks(BPNNs)for evaluating the freshness of bighead carp(Hypophthalmichthys nobilis)heads during chilled storage via fluorescence spectroscopy using an excitation-emission matrix(EEM).The total volatile basic nitrogen(TVB-N)and total aerobic count(TAC)of fish increased obviously during storage at 0,4,8,12,and 16°C,while sensory scores decreased with increasing storage time.The EEM fluorescence intensity was measured,and its change was correlated with the freshness indicators of the samples.Three characteristic components of EEM data were extracted by parallel factor analysis,and two freshness indicators were used to construct the EEM-BPNNs model.The results demonstrated that the relative errors of the EEM-BPNNs model for TVB-N and TAC were less than 14%.This result indicated that the EEM-BPNNs model could determine the freshness of fish in cold chains in a rapid and nondestructive way.
基金funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) Industrial Chair in Drinking Water Research at the University of Toronto
文摘The presence of municipal wastewater at the intake of a major drinking water treatment facility located on Lake Ontario was examined using fluorescence data collected during a period of continuous monitoring.In addition,controlled mixing of lake water and wastewater sampled from a local treatment facility were conducted using a bench-scale fluorescence system to quantify observed changes in natural organic matter.Multivariate linear regression was applied to components derived from parallel factors analysis.The resulting mean absolute error for predicted wastewater level was 0.22%(V/V,wastewater/lake water),indicating that wastewater detection at below 1.0%(V/V)was possible.Analyses of sucralose,a wastewater indicator,were conducted for treated wastewater as well as surface water collected at two intake locations on Lake Ontario.Results suggested minimal wastewater contribution at the drinking water intake.A wastewater detection model using a moving baseline was developed and applied to continuous fluorescence data collected at one of the drinking water intakes,which agreed well with sucralose results.Furthermore,the simulated addition of 1.0%(V/V)of wastewater/wastewater was detectable in 89%of samples analyzed,demonstrating the utility of fluorescence-based wastewater monitoring.
