Sudden temperature drops cause soils in natural environments to freeze unidirectionally,resulting in soil expansion and deformation that can lead to damage to engineering structures.The impact of temperature-induced f...Sudden temperature drops cause soils in natural environments to freeze unidirectionally,resulting in soil expansion and deformation that can lead to damage to engineering structures.The impact of temperature-induced freezing on deformation and solute migration in saline soils,especially under extended freezing,is not well understood due to the lack of knowledge regarding the microscopic mechanisms involved.This study investigated the expansion,deformation,and water-salt migration in chlorinated saline soils,materials commonly used for canal foundations in cold and arid regions,under different roof temperatures and soil compaction levels through unidirectional freezing experiments.The microscopic structures of saline soils were observed using scanning electron microscopy(SEM)and optical microscopy.A quantitative analysis of the microstructural data was conducted before and after freezing to elucidate the microscopic mechanisms of water-salt migration and deformation.The results indicate that soil swelling is enhanced by elevated roof temperatures approaching the soil's freezing point and soil compaction,which prolongs the duration and accelerates the rate of water-salt migration.The unidirectional freezing altered the microstructure of saline soils due to the continuous temperature gradients,leading to four distinct zones:natural frozen zone,peak frozen zone,gradual frozen zone,and unfrozen zone,each exhibiting significant changes in pore types and fractal dimensions.Vacuum suction at the colder end of the soil structure facilitates the upward migration of salt and water,which subsequently undergoes crystallization.This process expands the internal pore structure and causes swelling.The findings provide a theoretical basis for understanding the evolution of soil microstructure in cold and arid regions and for the management of saline soil engineering.展开更多
The first example of Nd@C_(3)N_(4)-photoredox/chlorine dual catalyzed alkylation with unactivated alkanes as the alkyl sources has been developed,which allows for the synthesis of various 4-alkylated cyclic sulfonyl k...The first example of Nd@C_(3)N_(4)-photoredox/chlorine dual catalyzed alkylation with unactivated alkanes as the alkyl sources has been developed,which allows for the synthesis of various 4-alkylated cyclic sulfonyl ketimines.In this process,chlorine functions as both a redox and hydrogen atom transfer catalyst.The synergism of the reversible Nd^(2+)/Nd^(3+)and Cl^(ˉ)/Cl˙redox pairs significantly enhances overall photocatalytic efficiency.The in vitro anticancer activity of 4-alkylated products was evaluated by using the CCK8assay against both human choroidal melanoma(MUM-2B)and lung cancer(A549)cell.Compound 3da showed approximately triple the potency of 5-fluorouracil.展开更多
Following the COVID-19 outbreak,a vast array of chlorine disinfectants was used to eliminate the virus,leading to inevitable discharge into aquatic ecosystems.These environments also contain various anthropogenic micr...Following the COVID-19 outbreak,a vast array of chlorine disinfectants was used to eliminate the virus,leading to inevitable discharge into aquatic ecosystems.These environments also contain various anthropogenic micropollutants,such as pharmaceuticals,which pose threats to the survival and activities of biological communities.Consequently,the presence of discharged chlorine disinfectants and pharmaceuticals can simultaneously impact the structure and function of aquatic ecosystems.To investigate the combined effects of chlorine disinfectants and pharmaceuticals on the periphyton and zoobenthos(Limnodrilus hoffmeisteri)community composition and function,we conducted a 12-flume reactor experiment using sodium hypochlorite and representative pharmaceuticals(abundant in the Yangtze River)as influents.Results demonstrated that the discharge of chlorine disinfectants further altered the composition of river prokaryotic communities.Eukaryotic organisms within the periphyton exhibited greater resilience to chlorine exposure compared to prokaryotic communities.Metagenomic analysis revealed that prokaryotic communities with different compositions can execute similar functions,while RNA sequencing indicated that co-exposure promoted biological processes such as focal adhesion and ribosome synthesis,but inhibited activities related to nitrogen metabolism and resistance to folate antimicrobials.Additionally,co-exposure induced oxidative stress in L.hoffmeisteri,leading to stronger environmental adaptation.展开更多
Halogenated aromatic disinfection byproducts(DBPs)are gradually receiving attention due to their high detection frequency and usually higher toxicity than regulated DBPs.In this study,we established a solid phase extr...Halogenated aromatic disinfection byproducts(DBPs)are gradually receiving attention due to their high detection frequency and usually higher toxicity than regulated DBPs.In this study,we established a solid phase extraction(SPE)-LC-MS/MS method to simultaneously trace analyze 59 halogenated aromatic DBPs.The limits of detection and limits of quantification of halogenated aromatic DBPs ranged from 0.03 to 135.23 ng/L and from 0.1 to 450.76 ng/L,respectively.The range of recoveries and relative standard deviation(RSD)in river water were between 72.41%to 119.54%and 1.86%to 16.03%,respectively.Therefore,this method can be used to accurately analyze trace levels of halogenated aromatic DBPs in drinking water.The occurrence and transformation of halogenated aromatic DBPs were explored based on this method.In the chlorinated simulated source water and chlorinated river water,20 and 45 halogenated aromatic DBPs were determined,respectively.The active halogen species(HOCl,HOBr,and HOI)first reacted with natural organic matter(NOM)to form halogenated aromatic DBPs.Then,chlorine further reacted with the halogenated aromatic DBPs to convert them into small-molecule halogenated aliphatic DBPs through oxidation,electrophilic substitution,and hydrolysis reaction,etc.In the chlorinated simulated source water,chlorinated river water,and tap water,the toxicity contribution of bromoacetic acids(Br-HAAs)accounted for themajority(>71.16%).Given that halogenated aromatic DBPs are intermediate products of halogenated aliphatic DBPs,controlling the formation of halogenated aromatic DBPs is beneficial in decreasing the formation of halogenated aliphatic DBPs,thereby diminishing the toxicity of drinking water.展开更多
Seawater electrolysis offers a promising pathway to generate green hydrogen,which is crucial for the net-zero emission targets.Indirect seawater electrolysis is severely limited by high energy demands and system compl...Seawater electrolysis offers a promising pathway to generate green hydrogen,which is crucial for the net-zero emission targets.Indirect seawater electrolysis is severely limited by high energy demands and system complexity,while the direct seawater electrolysis bypasses pre-treatment,offering a simpler and more cost-effective solution.However,the chlorine evolution reaction and impurities in the seawater lead to severe corrosion and hinder electrolysis’s efficiency.Herein,we review recent advances in the rational design of chlorine-suppressive catalysts and integrated electrolysis systems architectures for chloride-induced corrosion,with simultaneous enhancement of Faradaic efficiency and reduction of electrolysis’s cost.Furthermore,promising directions are proposed for durable and efficient seawater electrolysis systems.This review provides perspectives for seawater electrolysis toward sustainable energy conversion and environmental protection.展开更多
Layered sodium cobaltate(Na_(x)CoO_(2)),characterized by CoO_(2) slabs and intralayer edge-shared CoO_6 octahedra,holds promising potential as an electrocatalyst for chlorine evolution reaction(CER).However,the subopt...Layered sodium cobaltate(Na_(x)CoO_(2)),characterized by CoO_(2) slabs and intralayer edge-shared CoO_6 octahedra,holds promising potential as an electrocatalyst for chlorine evolution reaction(CER).However,the suboptimal adsorption of the intermediate on Na_(x)CoO_(2) resulted in unsatisfactory activity.Herein,Na_(x)CoO_(2) flakes with varying sodium densities(x=0.6,0.7,0.9)were engineered for efficient CER.Excitingly,the optimal Na_(0.7)CoO_(2) achieves an ultralow overpotential(55.47 mV)outperforming commercial RuO_(2) at 10 mA/cm^(2),while remaining inactive toward the competing OER.Experimental and theoretical calculations demonstrate that appropriate interlayer sodium density has optimized the d-band center level of Co atoms in Na_(x)CoO_(2),thereby weakening the strength of Co-Cl bonds.This modulation facilitates the adsorption-desorption equilibrium of Cl species(ΔG_(Cl^(*))=-0.109 eV)on the surface and kinetically accelerating Cl_2 release.This work is anticipated to elucidate the mechanism by which interlayer sodium density modifies the catalytic performance of Na_(x)CoO_(2),and present new insights for the rational design of advanced CER electrocatalysts.展开更多
Weight lost method was used to comparatively study the corrosion behavior of four different metals under the dosage of chlorine dioxide, chlorine and their mixture respectively. The experimental results indicated that...Weight lost method was used to comparatively study the corrosion behavior of four different metals under the dosage of chlorine dioxide, chlorine and their mixture respectively. The experimental results indicated that chlorine causes the most serious corrosion of carbon steel, and the higher the concentration of chlorine, the more serious the corrosion. On the contrary, metals corrosion is the least serious in the case of chlorine dioxide. The results further revealed that chlorine dioxide is the most effective water treatment reagent, making it the best choice to use extensively in circulated cooling water disinfection and corrosion control.展开更多
Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. I...Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this paper, a full-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Cyclops removal was conducted in a waterworks. The experimental results were compared with that of the existing prechlorination process in several aspects: including the Cyclops removal efficiencies of water samples taken from the outlets of sedimentation tank and sand filter and the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Cyclops than chlorine and Cyclops could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that of prechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.展开更多
A method was developed for determination of chlorine and bromine in plant materials by ion chromatography using temperature programing-semi molten for sample preparation. Values of detection limits of the method found...A method was developed for determination of chlorine and bromine in plant materials by ion chromatography using temperature programing-semi molten for sample preparation. Values of detection limits of the method found were 1.0×10^-5 for CI and 1.3×10^-6 for Br. The measuring range of the method found were 0.3-20.0 mg/L for CI and 4,0-120,0 μg/L for Br. The results obtained agreed quite well with those reference values.展开更多
Hazardous waste dechlorination reduces the potential of creating dioxins during the incineration process. To investigate the salt effect on waste dechlorination, molten hydroxides with a low melting temperature were u...Hazardous waste dechlorination reduces the potential of creating dioxins during the incineration process. To investigate the salt effect on waste dechlorination, molten hydroxides with a low melting temperature were utilized for the pre-dechlorination and decomposition of chlorine-containing organic wastes(COWs) including trichlorobenzene(TCB),perchloroethylene, hexachlorobenzene and chlordane. The results showed that a eutectic mixture of caustic sodium and potassium hydroxides(41 wt.% NaOH and 59 wt.% KOH) led to a low melting point below 300°C and a relatively high chlorine retention efficiency(CRE) with TCB as a representative COWs. The amounts of hydroxides, reaction time, and temperature all had notable influence on CRE. When the mass ratio of hydroxides to TCB reached 30:1,approximately 98.1% of the TCB was destroyed within 2.5 hr at 300°C with CRE of 71.6%.According to the residue analysis, the shapes of reaction residues were irregular with particles becoming swollen and porous. The benzene ring and C–Cl bonds disappeared, while carboxyl groups formed in the residues. The stripped chlorine was retained and condensed to form chloride salts, and the relative abundance of the chloride ions associated with the mass of TCB in residues increased from 0 to 75.0% within the 2.5 hr reaction time. The observed concentration of dioxins in residues was 5.6 ngTEQ/kg. A reaction pathway and possible additional reactions that occur in this dechlorination system were proposed. Oxidizing agents may attack TCB and facilitate hydrogenation/dechlorination reactions, making this process a promising and environmentally friendly approach for chlorine-containing organic waste treatment.展开更多
Chironomid larvae propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfection process like chlorination due to its stronger resistance to oxidation. In this...Chironomid larvae propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfection process like chlorination due to its stronger resistance to oxidation. In this paper, a pilot-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Chironomid larvae removal was conducted in Shenzhen Waterworks in Guangdong Province, China. The experimental results were compared with that of the existing prechlorination process in several aspects, including the Chironomid larvae removal efficiencies of water samples taken from the outlets of sedimentation tank, sand filter, the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Chironomid larvae than chlorine and Chironomid larvae could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that ofprechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.展开更多
Objective To better understand the mechanism of chlorine resistance of mycobacteria and evaluate the efficiency of various disinfection processes.Methods Inactivation experiments of one strain Mycobacteria mucogenicum...Objective To better understand the mechanism of chlorine resistance of mycobacteria and evaluate the efficiency of various disinfection processes.Methods Inactivation experiments of one strain Mycobacteria mucogenicum,isolated from a drinking water distribution system in South China were conducted with various chlorine disinfectants.Inactivation efficiency and disinfectant residual,as well as the formation of organic chloramines,were measured during the experiments.Results This strain of M.mucogenicum showed high resistance to chlorine.The CT values of 99.9% inactivation by free chlorine,monochloramine and chlorine dioxide were detected as 29.6±1.46,170±6.16,and 10.9±1.55 min（mg/L） respectively,indicating that chlorine dioxide exhibited significantly higher efficiency than free chlorine and monochloramine.It was also found that M.mucogenicum reacted with chlorine disinfectants more slowly than S.aureus,but consumed more chlorine disinfectants during longer time of contact.Lipid analysis of the cell construction revealed that 95.7% of cell membrane lipid of M.mucogenicum was composed of saturated long chain fatty acids.Saturated fatty acids were regarded as more stable and more hydrophilic which enabled the cell membrane to prevent the diffusion of chlorine.Conclusion It was concluded that different compositions of cell membrane might endow M.mucogenicum with a higher chlorine resistance.展开更多
We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then ...We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then the chlorine ion selective membrane is formed on the sensing window,and the fabrication of the EGFET chlorine ion sensing device is completed.The surface potential on the sensing membrane of the EGFET chlorine ion sensing device will be changed in the different chlorine ion concentration solutions,then changes further gate voltage and drain current to detect chlorine ion concentration.We will study non-ideal effects such as temperature,hysteresis and drift effects for the EGFET chlorine ion sensing device in this paper,these researches will help us to improve the sensing characteristics of the EGFET chlorine ion sensing device.展开更多
Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catal...Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.展开更多
Increasing demand is fueling the booming polyurethane industry worldwide. An impeding issue for poly- urethane industry is how to handle the large quantity of hydrogen chloride byproduct generated from the synthesis o...Increasing demand is fueling the booming polyurethane industry worldwide. An impeding issue for poly- urethane industry is how to handle the large quantity of hydrogen chloride byproduct generated from the synthesis of intermediates, i.e., isocyanates. In the meantime, the traditional chloro-alkaline process sufibrs both from the high en- ergy intensity of electrolysis method and the disparity in the chlorine and caustic soda market. To solve these prob- lems, the state-of-the-art chlorine recycling technologies are reviewed and compared. Approaches for cost-effective utilization of chlorine in polyurethane industry are investigated. Chinese academies and enterprises＇ on-going effort on the development of a novel hydrogen chloride oxidation process for the synthesis of chlorine is presented. With this process, the closed loop recycling of chlorine can be realized. Tremendous economic, environmental and social bene- fits can be expected. A wide adoption of this technology will significantly advance the sustainable development of polyurethane industry.展开更多
This paper presents a system approach of mass balance calculations of ozone and other species under diffusion-convection-reaction processes to study the impacts of major ozone-depleting chemicals, chlorine (Cl) and ch...This paper presents a system approach of mass balance calculations of ozone and other species under diffusion-convection-reaction processes to study the impacts of major ozone-depleting chemicals, chlorine (Cl) and chlorine monoxide (ClO), and the effect of photolysis on ozone concentrations, ozone depletion, total ozone abundance, and ozone layer along the altitude in the stratosphere. The calculated ozone concentrations and profile of the layer followed a similar trend and were generally in good agreement with the measurements above the tropical area. The calculated peak of the layer was at the same mid-stratosphere at Z = 30 km with a peak concentration and total ozone abundance about 20% higher than the measured peak concentration of 8.0 ppm and total abundance of 399 DU. In the presence of Cl and ClO, the calculated ozone concentrations and total abundance were substantially reduced. Cl generally depleted more uniformly of ozone across the altitude, while ClO reduced substantially the ozone in the upper stratosphere and thus shifted the peak of the layer to a much lower elevation at Z = 14 km. Although both ClO and Cl are active ozone-depleting chemicals, ClO was found to have a more pronounced impact on ozone depletion and distribution than Cl. The possible explanations of these interesting phenomena were discussed and elaborated. The approach and calculations in this paper were shown to be useful in providing an initial insight into the structure and behavior of the complex ozone layer.展开更多
First, the date palm kernel is used to produce granular activated carbon （GAC） by a physiochemical activation process. The process involves six steps： washing, drying, crushing, sieving, carbonization, and activati...First, the date palm kernel is used to produce granular activated carbon （GAC） by a physiochemical activation process. The process involves six steps： washing, drying, crushing, sieving, carbonization, and activation. Secondly, the ability of the produced GAC to remove pollutants is examined through batch experiments of residual chlorine adsorption whereas the equilibrium isotherm experimental data are tested for the Langmuir and Freundlich isotherms equations. Thirdly, the experimental and theoretical study of dynamic adsorption process and the effect of major operating parameters on dynamic adsorption are investigated. The results show that the Langmuir isotherm gives the best fitting to experimental data, which indicates that the residual chlorine adsorption can be characterized by mono layer adsorption behavior. The produced GAC has a great potential as an adsorbent for residual chlorine in water systems and it can compete favorably with the conventional adsorbents. The Thomas extended model with combined mass transfer resistances is used for verifying the experimental results and the results show that the proposed model coincides well with the experimental data of the dynamic adsorption process.展开更多
Chlorine(Cl) is extensively present in solid wastes, causing significant problems during the thermal conversion of waste to energy or fuels, by combustion, gasification or pyrolysis.This paper introduces the analytica...Chlorine(Cl) is extensively present in solid wastes, causing significant problems during the thermal conversion of waste to energy or fuels, by combustion, gasification or pyrolysis.This paper introduces the analytical methods for determining the Cl content in solid materials and presents the concentrations of Cl in various types of wastes, as reported in literature. Then, it provides a comprehensive analysis on the Cl emission behavior and Cl species formed during the thermal processing of the inorganic and organic Cl sources. The challenges resulted from the reactions between the formed Cl species and the ferrous metals, the heavy metals and the organic matters are summarized and discussed, e.g., high temperature corrosion, heavy metal evaporation and dioxin formation. The quality degradation of products(oil, char and syngas) by Cl is analyzed. Finally, the available controlling methods of Cl emission, including pre-treatment(water washing, sorting,microwave irradiation and stepwise pyrolysis) and in-furnace(absorbents, co-treatment and catalysts) methods are assessed.展开更多
The impact of moisture on the partitioning of the heavy metals including Pb,Zn,Cu and Cd in municipal solid waste （MSW） was studied in a laboratory tubular furnace.A thermodynamic investigation using CHEMKIN softwar...The impact of moisture on the partitioning of the heavy metals including Pb,Zn,Cu and Cd in municipal solid waste （MSW） was studied in a laboratory tubular furnace.A thermodynamic investigation using CHEMKIN software was performed to compare the experimental results.Simulated waste,representative of typical MSW with and without chlorine compounds,was burned at the background temperature of 700 and 950°C,respectively.In the absence of chlorine,the moisture content has no evident effect on the volatility of Pb,Zn and Cu at either 700 or 950°C,however,as flue gas moisture increasing the Cd distribution in the bottom ash increased at 700°C and reduced at 950°C,respectively.In the presence of chlorine,the flue gas moisture reduced the volatility of Pb,Zn and Cu due to the transformation of the more volatile metal chlorides into less volatile metal oxides,and the reduction became significant as chlorine content increase.For Cd,the chlorine promotes its volatility through the formation of more volatile CdCl 2.As a result,the increased moisture content increases the Pb,Zn,Cu and Cd concentrations in the bottom ash,which limits the utilization of the bottom ash as a construction material.Therefore,in order to accumulate heavy metals into the fly ash,MSW should be dried before incineration.展开更多
The variations in the isotopic compositions of chlorine in evaporation controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs 2Cl + ion by...The variations in the isotopic compositions of chlorine in evaporation controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs 2Cl + ion by thermal ionization mass spectrometry. The results showed that variation in δ 37 Cl values in these evaporation controlled brines are attributable to evaporation of brine accompanied by the deposition of saline minerals. The isotopic fractionation of chlorine between the deposited saline mineral and the co existing brine caused the variation of δ 37 Cl values in the brine. In general the isotopic fractionation of chlorine in nature indicates enrichment of 3 7Cl in the solid phase relative to 3 5Cl. The reverse isotopic fractionation of chlorine in which 3 5Cl is enriched in the solid phase, was observed to some extent during quick deposition under laboratory conditions as well as in nature. The mechanism of isotopic fractionation of chlorine during evaporation deposition was studied.展开更多
基金supported by the Open Fund of State Key Laboratory of Frozen Soil Engineering (Grant No.SKLFSE201806)the National Natural Science Foundation of China (Grant No.42177155).
文摘Sudden temperature drops cause soils in natural environments to freeze unidirectionally,resulting in soil expansion and deformation that can lead to damage to engineering structures.The impact of temperature-induced freezing on deformation and solute migration in saline soils,especially under extended freezing,is not well understood due to the lack of knowledge regarding the microscopic mechanisms involved.This study investigated the expansion,deformation,and water-salt migration in chlorinated saline soils,materials commonly used for canal foundations in cold and arid regions,under different roof temperatures and soil compaction levels through unidirectional freezing experiments.The microscopic structures of saline soils were observed using scanning electron microscopy(SEM)and optical microscopy.A quantitative analysis of the microstructural data was conducted before and after freezing to elucidate the microscopic mechanisms of water-salt migration and deformation.The results indicate that soil swelling is enhanced by elevated roof temperatures approaching the soil's freezing point and soil compaction,which prolongs the duration and accelerates the rate of water-salt migration.The unidirectional freezing altered the microstructure of saline soils due to the continuous temperature gradients,leading to four distinct zones:natural frozen zone,peak frozen zone,gradual frozen zone,and unfrozen zone,each exhibiting significant changes in pore types and fractal dimensions.Vacuum suction at the colder end of the soil structure facilitates the upward migration of salt and water,which subsequently undergoes crystallization.This process expands the internal pore structure and causes swelling.The findings provide a theoretical basis for understanding the evolution of soil microstructure in cold and arid regions and for the management of saline soil engineering.
基金supported by grants from the Provincial Natural Science Foundation of Hunan(No.2023JJ60335)。
文摘The first example of Nd@C_(3)N_(4)-photoredox/chlorine dual catalyzed alkylation with unactivated alkanes as the alkyl sources has been developed,which allows for the synthesis of various 4-alkylated cyclic sulfonyl ketimines.In this process,chlorine functions as both a redox and hydrogen atom transfer catalyst.The synergism of the reversible Nd^(2+)/Nd^(3+)and Cl^(ˉ)/Cl˙redox pairs significantly enhances overall photocatalytic efficiency.The in vitro anticancer activity of 4-alkylated products was evaluated by using the CCK8assay against both human choroidal melanoma(MUM-2B)and lung cancer(A549)cell.Compound 3da showed approximately triple the potency of 5-fluorouracil.
基金supported by the National Natural Science Foundation of China(Nos.52293442,52300249,and 52388101)the Scientific Research Project of China Three Gorges Corporation(No.201903139).
文摘Following the COVID-19 outbreak,a vast array of chlorine disinfectants was used to eliminate the virus,leading to inevitable discharge into aquatic ecosystems.These environments also contain various anthropogenic micropollutants,such as pharmaceuticals,which pose threats to the survival and activities of biological communities.Consequently,the presence of discharged chlorine disinfectants and pharmaceuticals can simultaneously impact the structure and function of aquatic ecosystems.To investigate the combined effects of chlorine disinfectants and pharmaceuticals on the periphyton and zoobenthos(Limnodrilus hoffmeisteri)community composition and function,we conducted a 12-flume reactor experiment using sodium hypochlorite and representative pharmaceuticals(abundant in the Yangtze River)as influents.Results demonstrated that the discharge of chlorine disinfectants further altered the composition of river prokaryotic communities.Eukaryotic organisms within the periphyton exhibited greater resilience to chlorine exposure compared to prokaryotic communities.Metagenomic analysis revealed that prokaryotic communities with different compositions can execute similar functions,while RNA sequencing indicated that co-exposure promoted biological processes such as focal adhesion and ribosome synthesis,but inhibited activities related to nitrogen metabolism and resistance to folate antimicrobials.Additionally,co-exposure induced oxidative stress in L.hoffmeisteri,leading to stronger environmental adaptation.
基金supported by the National Natural Science Foundation of China(No.52300005)China Postdoctoral Science Foundation(No.2023TQ0098)+5 种基金Heilongjiang Postdoctoral Fund(No.LBH-Z23175)Heilongjiang Touyan Innovation Team Program(No.HIT-SE-01)the Crossover Fund of Medical Engineering Science of Harbin Institute of Technology(No.IR2021107)the National Natural Science Foundation of International(Regional)Cooperation and Exchange Project(No.51961125104)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2022TS15)the Ecological and Environmental Protection Research Project of Heilongjiang Province(No.HST2022ST006).
文摘Halogenated aromatic disinfection byproducts(DBPs)are gradually receiving attention due to their high detection frequency and usually higher toxicity than regulated DBPs.In this study,we established a solid phase extraction(SPE)-LC-MS/MS method to simultaneously trace analyze 59 halogenated aromatic DBPs.The limits of detection and limits of quantification of halogenated aromatic DBPs ranged from 0.03 to 135.23 ng/L and from 0.1 to 450.76 ng/L,respectively.The range of recoveries and relative standard deviation(RSD)in river water were between 72.41%to 119.54%and 1.86%to 16.03%,respectively.Therefore,this method can be used to accurately analyze trace levels of halogenated aromatic DBPs in drinking water.The occurrence and transformation of halogenated aromatic DBPs were explored based on this method.In the chlorinated simulated source water and chlorinated river water,20 and 45 halogenated aromatic DBPs were determined,respectively.The active halogen species(HOCl,HOBr,and HOI)first reacted with natural organic matter(NOM)to form halogenated aromatic DBPs.Then,chlorine further reacted with the halogenated aromatic DBPs to convert them into small-molecule halogenated aliphatic DBPs through oxidation,electrophilic substitution,and hydrolysis reaction,etc.In the chlorinated simulated source water,chlorinated river water,and tap water,the toxicity contribution of bromoacetic acids(Br-HAAs)accounted for themajority(>71.16%).Given that halogenated aromatic DBPs are intermediate products of halogenated aliphatic DBPs,controlling the formation of halogenated aromatic DBPs is beneficial in decreasing the formation of halogenated aliphatic DBPs,thereby diminishing the toxicity of drinking water.
基金supported by the National Natural Science Foundation of China(Nos.22208376,UA22A20429)Shandong Provincial Natural Science Foundation(Nos.ZR2024QB175,ZR2023LFG005)+1 种基金Qingdao New Energy Shandong Laboratory Open Project(QNESL OP 202303)Ministry of Education University-Industry Collaborative Education Program(No.230804132140429).
文摘Seawater electrolysis offers a promising pathway to generate green hydrogen,which is crucial for the net-zero emission targets.Indirect seawater electrolysis is severely limited by high energy demands and system complexity,while the direct seawater electrolysis bypasses pre-treatment,offering a simpler and more cost-effective solution.However,the chlorine evolution reaction and impurities in the seawater lead to severe corrosion and hinder electrolysis’s efficiency.Herein,we review recent advances in the rational design of chlorine-suppressive catalysts and integrated electrolysis systems architectures for chloride-induced corrosion,with simultaneous enhancement of Faradaic efficiency and reduction of electrolysis’s cost.Furthermore,promising directions are proposed for durable and efficient seawater electrolysis systems.This review provides perspectives for seawater electrolysis toward sustainable energy conversion and environmental protection.
基金jointly supported by the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.24JR031)the Research Fund of Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials(No.SKL001)+1 种基金the National Natural Science Foundation of China(No.52372288)the Natural Science Basic Research Program of Shaanxi(No.2022JQ-373)。
文摘Layered sodium cobaltate(Na_(x)CoO_(2)),characterized by CoO_(2) slabs and intralayer edge-shared CoO_6 octahedra,holds promising potential as an electrocatalyst for chlorine evolution reaction(CER).However,the suboptimal adsorption of the intermediate on Na_(x)CoO_(2) resulted in unsatisfactory activity.Herein,Na_(x)CoO_(2) flakes with varying sodium densities(x=0.6,0.7,0.9)were engineered for efficient CER.Excitingly,the optimal Na_(0.7)CoO_(2) achieves an ultralow overpotential(55.47 mV)outperforming commercial RuO_(2) at 10 mA/cm^(2),while remaining inactive toward the competing OER.Experimental and theoretical calculations demonstrate that appropriate interlayer sodium density has optimized the d-band center level of Co atoms in Na_(x)CoO_(2),thereby weakening the strength of Co-Cl bonds.This modulation facilitates the adsorption-desorption equilibrium of Cl species(ΔG_(Cl^(*))=-0.109 eV)on the surface and kinetically accelerating Cl_2 release.This work is anticipated to elucidate the mechanism by which interlayer sodium density modifies the catalytic performance of Na_(x)CoO_(2),and present new insights for the rational design of advanced CER electrocatalysts.
文摘Weight lost method was used to comparatively study the corrosion behavior of four different metals under the dosage of chlorine dioxide, chlorine and their mixture respectively. The experimental results indicated that chlorine causes the most serious corrosion of carbon steel, and the higher the concentration of chlorine, the more serious the corrosion. On the contrary, metals corrosion is the least serious in the case of chlorine dioxide. The results further revealed that chlorine dioxide is the most effective water treatment reagent, making it the best choice to use extensively in circulated cooling water disinfection and corrosion control.
文摘Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this paper, a full-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Cyclops removal was conducted in a waterworks. The experimental results were compared with that of the existing prechlorination process in several aspects: including the Cyclops removal efficiencies of water samples taken from the outlets of sedimentation tank and sand filter and the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Cyclops than chlorine and Cyclops could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that of prechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.
文摘A method was developed for determination of chlorine and bromine in plant materials by ion chromatography using temperature programing-semi molten for sample preparation. Values of detection limits of the method found were 1.0×10^-5 for CI and 1.3×10^-6 for Br. The measuring range of the method found were 0.3-20.0 mg/L for CI and 4,0-120,0 μg/L for Br. The results obtained agreed quite well with those reference values.
基金supported by the National Natural Science Foundation of China(No.21677112)the Science and Technology Program of Ministry of Housing and Urban–Rural Development(No.2015-K7-021)
文摘Hazardous waste dechlorination reduces the potential of creating dioxins during the incineration process. To investigate the salt effect on waste dechlorination, molten hydroxides with a low melting temperature were utilized for the pre-dechlorination and decomposition of chlorine-containing organic wastes(COWs) including trichlorobenzene(TCB),perchloroethylene, hexachlorobenzene and chlordane. The results showed that a eutectic mixture of caustic sodium and potassium hydroxides(41 wt.% NaOH and 59 wt.% KOH) led to a low melting point below 300°C and a relatively high chlorine retention efficiency(CRE) with TCB as a representative COWs. The amounts of hydroxides, reaction time, and temperature all had notable influence on CRE. When the mass ratio of hydroxides to TCB reached 30:1,approximately 98.1% of the TCB was destroyed within 2.5 hr at 300°C with CRE of 71.6%.According to the residue analysis, the shapes of reaction residues were irregular with particles becoming swollen and porous. The benzene ring and C–Cl bonds disappeared, while carboxyl groups formed in the residues. The stripped chlorine was retained and condensed to form chloride salts, and the relative abundance of the chloride ions associated with the mass of TCB in residues increased from 0 to 75.0% within the 2.5 hr reaction time. The observed concentration of dioxins in residues was 5.6 ngTEQ/kg. A reaction pathway and possible additional reactions that occur in this dechlorination system were proposed. Oxidizing agents may attack TCB and facilitate hydrogenation/dechlorination reactions, making this process a promising and environmentally friendly approach for chlorine-containing organic waste treatment.
文摘Chironomid larvae propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfection process like chlorination due to its stronger resistance to oxidation. In this paper, a pilot-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Chironomid larvae removal was conducted in Shenzhen Waterworks in Guangdong Province, China. The experimental results were compared with that of the existing prechlorination process in several aspects, including the Chironomid larvae removal efficiencies of water samples taken from the outlets of sedimentation tank, sand filter, the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Chironomid larvae than chlorine and Chironomid larvae could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that ofprechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.
基金funded by the Major Science and Technology Program for Water Pollution Control and Treatment (No. 2008ZX07420‐005)National Natural Science Foundation of China (No. 50708050)
文摘Objective To better understand the mechanism of chlorine resistance of mycobacteria and evaluate the efficiency of various disinfection processes.Methods Inactivation experiments of one strain Mycobacteria mucogenicum,isolated from a drinking water distribution system in South China were conducted with various chlorine disinfectants.Inactivation efficiency and disinfectant residual,as well as the formation of organic chloramines,were measured during the experiments.Results This strain of M.mucogenicum showed high resistance to chlorine.The CT values of 99.9% inactivation by free chlorine,monochloramine and chlorine dioxide were detected as 29.6±1.46,170±6.16,and 10.9±1.55 min（mg/L） respectively,indicating that chlorine dioxide exhibited significantly higher efficiency than free chlorine and monochloramine.It was also found that M.mucogenicum reacted with chlorine disinfectants more slowly than S.aureus,but consumed more chlorine disinfectants during longer time of contact.Lipid analysis of the cell construction revealed that 95.7% of cell membrane lipid of M.mucogenicum was composed of saturated long chain fatty acids.Saturated fatty acids were regarded as more stable and more hydrophilic which enabled the cell membrane to prevent the diffusion of chlorine.Conclusion It was concluded that different compositions of cell membrane might endow M.mucogenicum with a higher chlorine resistance.
文摘We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then the chlorine ion selective membrane is formed on the sensing window,and the fabrication of the EGFET chlorine ion sensing device is completed.The surface potential on the sensing membrane of the EGFET chlorine ion sensing device will be changed in the different chlorine ion concentration solutions,then changes further gate voltage and drain current to detect chlorine ion concentration.We will study non-ideal effects such as temperature,hysteresis and drift effects for the EGFET chlorine ion sensing device in this paper,these researches will help us to improve the sensing characteristics of the EGFET chlorine ion sensing device.
基金the National Natural Science Foundation of China(U21A20286,22206054 and 21805069)Natural Science Foundation of Hubei(2021CFB094)the Fundamental Research Funds for the Central China Normal University(CCNU)for financial support。
文摘Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.
文摘Increasing demand is fueling the booming polyurethane industry worldwide. An impeding issue for poly- urethane industry is how to handle the large quantity of hydrogen chloride byproduct generated from the synthesis of intermediates, i.e., isocyanates. In the meantime, the traditional chloro-alkaline process sufibrs both from the high en- ergy intensity of electrolysis method and the disparity in the chlorine and caustic soda market. To solve these prob- lems, the state-of-the-art chlorine recycling technologies are reviewed and compared. Approaches for cost-effective utilization of chlorine in polyurethane industry are investigated. Chinese academies and enterprises＇ on-going effort on the development of a novel hydrogen chloride oxidation process for the synthesis of chlorine is presented. With this process, the closed loop recycling of chlorine can be realized. Tremendous economic, environmental and social bene- fits can be expected. A wide adoption of this technology will significantly advance the sustainable development of polyurethane industry.
文摘This paper presents a system approach of mass balance calculations of ozone and other species under diffusion-convection-reaction processes to study the impacts of major ozone-depleting chemicals, chlorine (Cl) and chlorine monoxide (ClO), and the effect of photolysis on ozone concentrations, ozone depletion, total ozone abundance, and ozone layer along the altitude in the stratosphere. The calculated ozone concentrations and profile of the layer followed a similar trend and were generally in good agreement with the measurements above the tropical area. The calculated peak of the layer was at the same mid-stratosphere at Z = 30 km with a peak concentration and total ozone abundance about 20% higher than the measured peak concentration of 8.0 ppm and total abundance of 399 DU. In the presence of Cl and ClO, the calculated ozone concentrations and total abundance were substantially reduced. Cl generally depleted more uniformly of ozone across the altitude, while ClO reduced substantially the ozone in the upper stratosphere and thus shifted the peak of the layer to a much lower elevation at Z = 14 km. Although both ClO and Cl are active ozone-depleting chemicals, ClO was found to have a more pronounced impact on ozone depletion and distribution than Cl. The possible explanations of these interesting phenomena were discussed and elaborated. The approach and calculations in this paper were shown to be useful in providing an initial insight into the structure and behavior of the complex ozone layer.
基金The National Natural Science Foundation of China(No. 51078074)
文摘First, the date palm kernel is used to produce granular activated carbon （GAC） by a physiochemical activation process. The process involves six steps： washing, drying, crushing, sieving, carbonization, and activation. Secondly, the ability of the produced GAC to remove pollutants is examined through batch experiments of residual chlorine adsorption whereas the equilibrium isotherm experimental data are tested for the Langmuir and Freundlich isotherms equations. Thirdly, the experimental and theoretical study of dynamic adsorption process and the effect of major operating parameters on dynamic adsorption are investigated. The results show that the Langmuir isotherm gives the best fitting to experimental data, which indicates that the residual chlorine adsorption can be characterized by mono layer adsorption behavior. The produced GAC has a great potential as an adsorbent for residual chlorine in water systems and it can compete favorably with the conventional adsorbents. The Thomas extended model with combined mass transfer resistances is used for verifying the experimental results and the results show that the proposed model coincides well with the experimental data of the dynamic adsorption process.
基金supported by the National Natural Science Foundation of China (Nos. 51621005, 51676170)the Key Project for Strategic International Collaboration on Science and Technology Innovation of the National Key R&D Program of China (No. 2016YFE0202000)+1 种基金 the Fundamental Research Funds for the Central Universities (No. 2017FZA4013)the Academic Raising Star Training Program for PhD Student of Zhejiang University
文摘Chlorine(Cl) is extensively present in solid wastes, causing significant problems during the thermal conversion of waste to energy or fuels, by combustion, gasification or pyrolysis.This paper introduces the analytical methods for determining the Cl content in solid materials and presents the concentrations of Cl in various types of wastes, as reported in literature. Then, it provides a comprehensive analysis on the Cl emission behavior and Cl species formed during the thermal processing of the inorganic and organic Cl sources. The challenges resulted from the reactions between the formed Cl species and the ferrous metals, the heavy metals and the organic matters are summarized and discussed, e.g., high temperature corrosion, heavy metal evaporation and dioxin formation. The quality degradation of products(oil, char and syngas) by Cl is analyzed. Finally, the available controlling methods of Cl emission, including pre-treatment(water washing, sorting,microwave irradiation and stepwise pyrolysis) and in-furnace(absorbents, co-treatment and catalysts) methods are assessed.
基金supported by the National Natural Science Foundation of China (No. 50776007)the Beijing Municipal Science and Technology Commission under the Municipal Solid Waste Development Program(No. H020620330120)
文摘The impact of moisture on the partitioning of the heavy metals including Pb,Zn,Cu and Cd in municipal solid waste （MSW） was studied in a laboratory tubular furnace.A thermodynamic investigation using CHEMKIN software was performed to compare the experimental results.Simulated waste,representative of typical MSW with and without chlorine compounds,was burned at the background temperature of 700 and 950°C,respectively.In the absence of chlorine,the moisture content has no evident effect on the volatility of Pb,Zn and Cu at either 700 or 950°C,however,as flue gas moisture increasing the Cd distribution in the bottom ash increased at 700°C and reduced at 950°C,respectively.In the presence of chlorine,the flue gas moisture reduced the volatility of Pb,Zn and Cu due to the transformation of the more volatile metal chlorides into less volatile metal oxides,and the reduction became significant as chlorine content increase.For Cd,the chlorine promotes its volatility through the formation of more volatile CdCl 2.As a result,the increased moisture content increases the Pb,Zn,Cu and Cd concentrations in the bottom ash,which limits the utilization of the bottom ash as a construction material.Therefore,in order to accumulate heavy metals into the fly ash,MSW should be dried before incineration.
文摘The variations in the isotopic compositions of chlorine in evaporation controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs 2Cl + ion by thermal ionization mass spectrometry. The results showed that variation in δ 37 Cl values in these evaporation controlled brines are attributable to evaporation of brine accompanied by the deposition of saline minerals. The isotopic fractionation of chlorine between the deposited saline mineral and the co existing brine caused the variation of δ 37 Cl values in the brine. In general the isotopic fractionation of chlorine in nature indicates enrichment of 3 7Cl in the solid phase relative to 3 5Cl. The reverse isotopic fractionation of chlorine in which 3 5Cl is enriched in the solid phase, was observed to some extent during quick deposition under laboratory conditions as well as in nature. The mechanism of isotopic fractionation of chlorine during evaporation deposition was studied.
