An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence(LIF)methods is developed to quantitatively measure the concentrations of hydroxyl in CH_4/air flat laminar f...An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence(LIF)methods is developed to quantitatively measure the concentrations of hydroxyl in CH_4/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.展开更多
[Objectives] The aim of this work was to compare the inhibitory effects of different water-soluble extracts of ginseng on hydroxyl radical. [Methods]The water-soluble effective parts of ginseng were extracted by ortho...[Objectives] The aim of this work was to compare the inhibitory effects of different water-soluble extracts of ginseng on hydroxyl radical. [Methods]The water-soluble effective parts of ginseng were extracted by orthogonal test,the hydroxyl radical scavenging rate of each extract was determined by salicylic acid method,and the extraction process of the optimum hydroxyl radical inhibitor was optimized using variance analysis and cluster analysis. [Results] A total of 16 samples were prepared. Among them,the sample No. 12 had the highest hydroxyl radical scavenging rate,and the inhibition rate reached 105. 08% at the concentration of 1 g/L. [Conclusions] Ginseng water extract contained hydroxyl radical scavenger,of which the optimum extraction process was as follows: p H of 8,solid to liquid ratio of 1∶ 10,extraction temperature of 4℃,extraction time of 12 h and extraction times of 3.展开更多
Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydrox...Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.展开更多
Co-crystal is a very potential kind of drug solid forms, and has a far-reaching influence on designing and preparing drugs. A new 1:1:1 co-crystal compound consisting of 4-amino-3,5-dichloro-benzenesulfonamide, 1,10-p...Co-crystal is a very potential kind of drug solid forms, and has a far-reaching influence on designing and preparing drugs. A new 1:1:1 co-crystal compound consisting of 4-amino-3,5-dichloro-benzenesulfonamide, 1,10-phenanthroline and water was synthesized, and its crystal structure was characterized by X-ray diffraction method. The compositions of the co-crystal are self-assembled into a three-dimensional network structure via intermolecular interactions including hydrogen bonds, π-π stacking, Cl???Cl interactions and van der Waals' forces. According to the evaluations of cytotoxicity assays, anti-microbial and anti-hydroxyl radicals, this co-crystal is a potential drug.展开更多
A new method was introduced to detect the concentration of OH radical in dielectric barrier discharge(DBD)reaction.A film, which was impregnated with salicylic acid,was used to detect OH radical in plasma reaction at ...A new method was introduced to detect the concentration of OH radical in dielectric barrier discharge(DBD)reaction.A film, which was impregnated with salicylic acid,was used to detect OH radical in plasma reaction at room temperature and atmospheric pressure.Salicylic acid reacts with OH radical and produces 2,5-dihydroxybenzoic acid(2,5-DHBA).Then,a high performance liquid chromatography(HPLC)was carried out to detect the concentration of 2,5-DHBA.Therefore,OH radical in nonthermal plasma reaction could be calculated.In this plasma reaction,the applied voltage was controlled at 10 kV,the initial concentration of toluene was 400 mg/m3,and the gas flow rate was 300 ml/min.It was observed that when the film was placed away from the plasma area,2,5-DHBA could not be detected by HPLC,although the sampling time lasted for 48 h.On the other hand,when the film was placed in the plasma area and the sampling time being too long(>4 h),the concentration of 2,5-DHBA was also below detection limit,and it could not be detected by HPLC.However,when the film was placed in the plasma reaction field with the sampling time being 3 h,the concentration of OH radical was calculated to be 10.54×1012 cm-3.In addition,concentration of OH radical was investigated under different humidity,such as 0.2%,0.4%,0.6%,0.8%,and 1.0%.The results showed that the amount of OH radical stayed at order of magnitude of 1012 cm-3 and increased with the increase of humidity.展开更多
The generation and transformation of radicals on the cathode of indirect electrochemical oxidation were studied by chemilumines- cence(CL)and UV-Visible spectra in the reactor with a salt bridge that connected the sep...The generation and transformation of radicals on the cathode of indirect electrochemical oxidation were studied by chemilumines- cence(CL)and UV-Visible spectra in the reactor with a salt bridge that connected the separated chambers.The CL intensity of 4×10^(-9)mol/L luminol on the cathode with bubbling oxygen was about seven times that of the intensity without it,which was because of the generation of reactive oxygen species(ROS).The existence of ROS,especially the generation of the superoxide radical,c...展开更多
In an aqueous solution, normal electrolysis at high voltages switches over sponta-neously to glow discharge electrolysis and gives rise to hydroxyl radical, hydrogen peroxide, andaqueous electron, as well as several o...In an aqueous solution, normal electrolysis at high voltages switches over sponta-neously to glow discharge electrolysis and gives rise to hydroxyl radical, hydrogen peroxide, andaqueous electron, as well as several other active species. Hydroxyl radical directly attacks or-ganic contaminants to make them oxidized. In the present paper, 2-naphthylamine is eventuallydegraded into hydrogen carbonate and carbon dioxide. The degradation process is analyzed byusing an Ultraviolet (UV) absorption spectrum, high-performance liquid chromatography (HPLC)and chemical oxygen demand (COD). It is demonstrated that 2-naphthylamine (c0 =30 mg.1-1) iscompletely converted within 2h at 30℃ and 600 V by glow discharge electrolysis, and the degra-dation is strongly dependent upon the presence of ferrous ions. COD is ascended in the absenceof ferrous ions and descended in the presence of them.展开更多
The high ratio concentration hydroxyl solution is produced by strong discharge, and applied to the prevention of invasive species in ship ballast water and red tide. This paper introduces the plasma process of hydroxy...The high ratio concentration hydroxyl solution is produced by strong discharge, and applied to the prevention of invasive species in ship ballast water and red tide. This paper introduces the plasma process of hydroxyl radical production, the production process of high ratio hydroxyl solution, and the application to treating ballast water and red tide.展开更多
The qualitative and quantitative analyses of reactive oxygen species are essential to determine their steady-state concentration and related reaction mechanisms in environmental aquatic systems. In this study, salicyl...The qualitative and quantitative analyses of reactive oxygen species are essential to determine their steady-state concentration and related reaction mechanisms in environmental aquatic systems. In this study, salicylic acid was employed as an innovative molecular probe of hydroxyl radical(OH) generated in aqueous nitrate and nitrite solutions through photochemical reactions. Kinetic studies showed that the steady-state concentrations of OH in aqueous NO- 3(10 mmol/L, pH=5) and NO- 2(10 mmol/L, pH=5) solutions under ultraviolet irradiation were at a same magnitude, 10 -15 mol/L. Apparent quantum yields of OH at 313 nm were measured as 0.011 and 0.07 for NO- 3 and NO- 2 respectively, all comparable to the results of previous studies.展开更多
The aim of the present work is to quantitatively measure the hydroxyl radical concentration by using LIF(laserinduced fluorescence) in flame.The detailed physical models of spectral absorption lineshape broadening,col...The aim of the present work is to quantitatively measure the hydroxyl radical concentration by using LIF(laserinduced fluorescence) in flame.The detailed physical models of spectral absorption lineshape broadening,collisional transition and quenching at elevated pressure are built.The fine energy level structure of the OH molecule is illustrated to understand the process with laser-induced fluorescence emission and others in the case without radiation,which include collisional quenching,rotational energy transfer(RET),and vibrational energy transfer(VET).Based on these,some numerical results are achieved by simulations in order to evaluate the fluorescence yield at elevated pressure.These results are useful for understanding the real physical processes in OH-LIF technique and finding a way to calibrate the signal for quantitative measurement of OH concentration in a practical combustor.展开更多
Effects of discharge mode,voltage applied,size of the nozzle discharge electrodeand flow rate of water on the generation of hydroxyl radical were investigated in air dischargewith atomized water,by using optical emiss...Effects of discharge mode,voltage applied,size of the nozzle discharge electrodeand flow rate of water on the generation of hydroxyl radical were investigated in air dischargewith atomized water,by using optical emission spectroscopy(OES).Water was injected into thedischarge region through the discharge nozzle electrode,and a large amount of fine water drops,formed and distributed in the discharge region,were observed.It was found that negative DCcorona discharge was more effective to generate the hydroxyl radicals in comparison to positiveDC corona discharge or negative pulsed discharge.A larger outer diameter of the nozzle electrodeor a stronger electric field is beneficial for hydroxyl-radical generation.Moreover,there is a criticalvalue in the flow rate of atomized water against the discharge voltage.Below this critical value,hydroxyl-radical generation increases with the increase in flow rate of the water,while above thisvalue,it decreases.In addition,it is observed that OES from the discharge is mainly in theultraviolet domain.The results are helpful in the study of the mechanism and application ofplasma in pollution-control in either air or water.展开更多
With physical method of micro-gap gas discharge, a large amount of hydroxyl radical can be produced in 20t/h pilot-scale system using the ionization of O2 and H2O. In this paper, the effect of biochemistry of hydroxyl...With physical method of micro-gap gas discharge, a large amount of hydroxyl radical can be produced in 20t/h pilot-scale system using the ionization of O2 and H2O. In this paper, the effect of biochemistry of hydroxyl radicals on introduced organisms in ballast water was experimentally investi- gated. The results indicate that the contents of chlorophyl-a, chlorophyl-b, chlorophyl-c and carotenoid are decreased by 35%–64% within 8.0s and further to the lowest limit of test 5 minutes. In addition, the main reasons of cell death are the lipid peroxidation, the strong destruction to the monose, amylose, pro- tein, DNA and RNA of cell, and damage in CAT, POD and SOD of antioxidant enzyme system.展开更多
Ab initio and density functional theory calculations have been carried out to investigate the reaction of hydroxyl radical (OH) and 1,1,1-trichloroethane (CH3CCl3). The potential energy surface has been given accordin...Ab initio and density functional theory calculations have been carried out to investigate the reaction of hydroxyl radical (OH) and 1,1,1-trichloroethane (CH3CCl3). The potential energy surface has been given according to the relative energies calculated at the MP2/cc-pVTZ level after the spin projection (PMP2). Five reaction channels were identified and the intramolecular hydrogen bonding was observed in some transition state structures. The barrier heights and reaction enthalpies calculated for all possible channels show that the hydrogen abstraction channel is predominant kinetically and thermodynamically. The contribution from other channels was predicted to be minor.展开更多
Lead dioxide electrodes on Ti substrates were prepared by thermal-deposition or electro-deposition. The amount of hydroxyl radicals generated at the electrodes prepared by the above-mentioned two methods was compared ...Lead dioxide electrodes on Ti substrates were prepared by thermal-deposition or electro-deposition. The amount of hydroxyl radicals generated at the electrodes prepared by the above-mentioned two methods was compared with that at the electrodes mingled with Bi or La prepared by electro-deposition. The experimental results indicate that the highest concentration of hydroxyl radicals generated by thermal-deposition, electro-deposition mingled with nothing, electro-deposition mingled with Bi or La was 0.781, 1.048, 1.838 or 2.044 μmol/L, respectively. When phenol was electrolyzed on the four electrodes at a current density of 30 mA/cm2, the removal efficiency of phenol after electrolysis for 1.5 h was 87.30%, 93.55%, 97.95% or 98.70%, TOC removal efficiency after electrolysis for 5 h was 86.76%, 94.26%, 98.53% or 99.60%, respectively. Through the degradation experiments of phenol, the amount of hydroxyl radicals was responsible for the removal efficiency of phenol. The electro-catalytic characteristics were investigated by SEM, the generation amount of hydroxyl radicals, the degradation degree of phenol and the stability and conductivity of the electrodes were also investigated. The experimental results indicate that the four electrodes all show good electro-catalytic characteristics; the electro-catalytic characteristics of the electrode mingled with La were superior to those of the other three ones, and the electrochemical degradation of phenol followed one-step reaction dynamics.展开更多
With the physical method of micro-gap gas discharge,OH.radicals were producedby the ionization of 02 in air and H_O in the gaseous state,in order to explore more effectivemethod totreat the ship's ballast water.Th...With the physical method of micro-gap gas discharge,OH.radicals were producedby the ionization of 02 in air and H_O in the gaseous state,in order to explore more effectivemethod totreat the ship's ballast water.The surface morphology of Al_2O_3 dielectric layer wasanalysed using Atomic Force Microscopy(AFM),where the size of Al_2O3 particles was in the rangeof 2 μm to 5 μm.At the same time,the biochemical effect of hydroxyl radicals on the introducedorganisms and the quality of ship's ballast water were studied.The results indicate that the mainreasons of cell death are lipid peroxide and damage of the antioxidant enzyme system in Catalase(CAT),Peroxidase(POD)and Superoxide dismutase(SOD).In addition,the quality of the ballastwater was greatly improved.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11272338)the Science and Technology on Scramjet Key Laboratory Funding,China(Grant No.STSKFKT 2013004)the China Scholarship Council
文摘An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence(LIF)methods is developed to quantitatively measure the concentrations of hydroxyl in CH_4/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.
基金Supported by Open Foundation of Key Laboratory of Ministry of Education for TCM Viscera-State Theory and Applications,Liaoning University of Traditional Chinese Medicine(ZYZX1709)Project of Education Department of Liaoning Province(L201606)China Postdoctoral Science Foundation(2013M530945)
文摘[Objectives] The aim of this work was to compare the inhibitory effects of different water-soluble extracts of ginseng on hydroxyl radical. [Methods]The water-soluble effective parts of ginseng were extracted by orthogonal test,the hydroxyl radical scavenging rate of each extract was determined by salicylic acid method,and the extraction process of the optimum hydroxyl radical inhibitor was optimized using variance analysis and cluster analysis. [Results] A total of 16 samples were prepared. Among them,the sample No. 12 had the highest hydroxyl radical scavenging rate,and the inhibition rate reached 105. 08% at the concentration of 1 g/L. [Conclusions] Ginseng water extract contained hydroxyl radical scavenger,of which the optimum extraction process was as follows: p H of 8,solid to liquid ratio of 1∶ 10,extraction temperature of 4℃,extraction time of 12 h and extraction times of 3.
文摘Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.
基金Supported by Guangxi Natural Science Foundation(No.2016GXNSFAA380292)National Natural Science Foundation of China(No.21661011)
文摘Co-crystal is a very potential kind of drug solid forms, and has a far-reaching influence on designing and preparing drugs. A new 1:1:1 co-crystal compound consisting of 4-amino-3,5-dichloro-benzenesulfonamide, 1,10-phenanthroline and water was synthesized, and its crystal structure was characterized by X-ray diffraction method. The compositions of the co-crystal are self-assembled into a three-dimensional network structure via intermolecular interactions including hydrogen bonds, π-π stacking, Cl???Cl interactions and van der Waals' forces. According to the evaluations of cytotoxicity assays, anti-microbial and anti-hydroxyl radicals, this co-crystal is a potential drug.
基金supported by the National Natural Sci-ence Foundation of China(No.50708021)the GuangzhouUniversity Xinmiao Project(No.gyf1-1001)the Guangzhou University Scientific Research Start-up Project(No.gyf1-1002)
文摘A new method was introduced to detect the concentration of OH radical in dielectric barrier discharge(DBD)reaction.A film, which was impregnated with salicylic acid,was used to detect OH radical in plasma reaction at room temperature and atmospheric pressure.Salicylic acid reacts with OH radical and produces 2,5-dihydroxybenzoic acid(2,5-DHBA).Then,a high performance liquid chromatography(HPLC)was carried out to detect the concentration of 2,5-DHBA.Therefore,OH radical in nonthermal plasma reaction could be calculated.In this plasma reaction,the applied voltage was controlled at 10 kV,the initial concentration of toluene was 400 mg/m3,and the gas flow rate was 300 ml/min.It was observed that when the film was placed away from the plasma area,2,5-DHBA could not be detected by HPLC,although the sampling time lasted for 48 h.On the other hand,when the film was placed in the plasma area and the sampling time being too long(>4 h),the concentration of 2,5-DHBA was also below detection limit,and it could not be detected by HPLC.However,when the film was placed in the plasma reaction field with the sampling time being 3 h,the concentration of OH radical was calculated to be 10.54×1012 cm-3.In addition,concentration of OH radical was investigated under different humidity,such as 0.2%,0.4%,0.6%,0.8%,and 1.0%.The results showed that the amount of OH radical stayed at order of magnitude of 1012 cm-3 and increased with the increase of humidity.
文摘The generation and transformation of radicals on the cathode of indirect electrochemical oxidation were studied by chemilumines- cence(CL)and UV-Visible spectra in the reactor with a salt bridge that connected the separated chambers.The CL intensity of 4×10^(-9)mol/L luminol on the cathode with bubbling oxygen was about seven times that of the intensity without it,which was because of the generation of reactive oxygen species(ROS).The existence of ROS,especially the generation of the superoxide radical,c...
基金The project supported in part by the Project of Key Science and Technology of Education Ministry (00250)the Nature Science Foundation of Gansu Province (3ZS041-A25-028)the Invention Project of Science and Technology (KJCXGC-01, NWNU), 2000
文摘In an aqueous solution, normal electrolysis at high voltages switches over sponta-neously to glow discharge electrolysis and gives rise to hydroxyl radical, hydrogen peroxide, andaqueous electron, as well as several other active species. Hydroxyl radical directly attacks or-ganic contaminants to make them oxidized. In the present paper, 2-naphthylamine is eventuallydegraded into hydrogen carbonate and carbon dioxide. The degradation process is analyzed byusing an Ultraviolet (UV) absorption spectrum, high-performance liquid chromatography (HPLC)and chemical oxygen demand (COD). It is demonstrated that 2-naphthylamine (c0 =30 mg.1-1) iscompletely converted within 2h at 30℃ and 600 V by glow discharge electrolysis, and the degra-dation is strongly dependent upon the presence of ferrous ions. COD is ascended in the absenceof ferrous ions and descended in the presence of them.
基金The study has been funded by Key Project of National Foundation Research from the Ministry of Science and Technology of China,(2002CCC00900),outlay:30,0000Key and General Projects of National Natural Science Foundation of China(NSFC:60371035),outlay:26,0000Key and General Projects of National Natural Science Foundation of China(NSFC:60471036),outlay:21,0000.
文摘The high ratio concentration hydroxyl solution is produced by strong discharge, and applied to the prevention of invasive species in ship ballast water and red tide. This paper introduces the plasma process of hydroxyl radical production, the production process of high ratio hydroxyl solution, and the application to treating ballast water and red tide.
文摘The qualitative and quantitative analyses of reactive oxygen species are essential to determine their steady-state concentration and related reaction mechanisms in environmental aquatic systems. In this study, salicylic acid was employed as an innovative molecular probe of hydroxyl radical(OH) generated in aqueous nitrate and nitrite solutions through photochemical reactions. Kinetic studies showed that the steady-state concentrations of OH in aqueous NO- 3(10 mmol/L, pH=5) and NO- 2(10 mmol/L, pH=5) solutions under ultraviolet irradiation were at a same magnitude, 10 -15 mol/L. Apparent quantum yields of OH at 313 nm were measured as 0.011 and 0.07 for NO- 3 and NO- 2 respectively, all comparable to the results of previous studies.
基金Project supported by the National Natural Science Foundation of China(Grant No.11272338)the Fund from the Science and Technology on Scramjet Key Laboratory,China(Grant No.STSKFKT2013004)
文摘The aim of the present work is to quantitatively measure the hydroxyl radical concentration by using LIF(laserinduced fluorescence) in flame.The detailed physical models of spectral absorption lineshape broadening,collisional transition and quenching at elevated pressure are built.The fine energy level structure of the OH molecule is illustrated to understand the process with laser-induced fluorescence emission and others in the case without radiation,which include collisional quenching,rotational energy transfer(RET),and vibrational energy transfer(VET).Based on these,some numerical results are achieved by simulations in order to evaluate the fluorescence yield at elevated pressure.These results are useful for understanding the real physical processes in OH-LIF technique and finding a way to calibrate the signal for quantitative measurement of OH concentration in a practical combustor.
基金supported by Science and Technology Commission of Shanghai Municipality of China(No.09ZR1421200)Shanghai Maritime University of China(No.2008462)
文摘Effects of discharge mode,voltage applied,size of the nozzle discharge electrodeand flow rate of water on the generation of hydroxyl radical were investigated in air dischargewith atomized water,by using optical emission spectroscopy(OES).Water was injected into thedischarge region through the discharge nozzle electrode,and a large amount of fine water drops,formed and distributed in the discharge region,were observed.It was found that negative DCcorona discharge was more effective to generate the hydroxyl radicals in comparison to positiveDC corona discharge or negative pulsed discharge.A larger outer diameter of the nozzle electrodeor a stronger electric field is beneficial for hydroxyl-radical generation.Moreover,there is a criticalvalue in the flow rate of atomized water against the discharge voltage.Below this critical value,hydroxyl-radical generation increases with the increase in flow rate of the water,while above thisvalue,it decreases.In addition,it is observed that OES from the discharge is mainly in theultraviolet domain.The results are helpful in the study of the mechanism and application ofplasma in pollution-control in either air or water.
基金Key Project of National Foundation Research from Science and Tech-nology, Ministry of China (2002CCC00900), Key and General Projects of NSFC (No. 60371035) and Project of Society Development of Dalian (2004B3SF181).
文摘With physical method of micro-gap gas discharge, a large amount of hydroxyl radical can be produced in 20t/h pilot-scale system using the ionization of O2 and H2O. In this paper, the effect of biochemistry of hydroxyl radicals on introduced organisms in ballast water was experimentally investi- gated. The results indicate that the contents of chlorophyl-a, chlorophyl-b, chlorophyl-c and carotenoid are decreased by 35%–64% within 8.0s and further to the lowest limit of test 5 minutes. In addition, the main reasons of cell death are the lipid peroxidation, the strong destruction to the monose, amylose, pro- tein, DNA and RNA of cell, and damage in CAT, POD and SOD of antioxidant enzyme system.
基金supported by the National Natural Science Foundation of China (No. 20573029)the Natural Science Foundation of Heilongjiang Province (No. B200905)
文摘Ab initio and density functional theory calculations have been carried out to investigate the reaction of hydroxyl radical (OH) and 1,1,1-trichloroethane (CH3CCl3). The potential energy surface has been given according to the relative energies calculated at the MP2/cc-pVTZ level after the spin projection (PMP2). Five reaction channels were identified and the intramolecular hydrogen bonding was observed in some transition state structures. The barrier heights and reaction enthalpies calculated for all possible channels show that the hydrogen abstraction channel is predominant kinetically and thermodynamically. The contribution from other channels was predicted to be minor.
基金the Environment Bureau of Jilin Province, China(No.2006-11)Scientific Institute of Changchun City(No. 2007KZ15)985 Project of Jilin University
文摘Lead dioxide electrodes on Ti substrates were prepared by thermal-deposition or electro-deposition. The amount of hydroxyl radicals generated at the electrodes prepared by the above-mentioned two methods was compared with that at the electrodes mingled with Bi or La prepared by electro-deposition. The experimental results indicate that the highest concentration of hydroxyl radicals generated by thermal-deposition, electro-deposition mingled with nothing, electro-deposition mingled with Bi or La was 0.781, 1.048, 1.838 or 2.044 μmol/L, respectively. When phenol was electrolyzed on the four electrodes at a current density of 30 mA/cm2, the removal efficiency of phenol after electrolysis for 1.5 h was 87.30%, 93.55%, 97.95% or 98.70%, TOC removal efficiency after electrolysis for 5 h was 86.76%, 94.26%, 98.53% or 99.60%, respectively. Through the degradation experiments of phenol, the amount of hydroxyl radicals was responsible for the removal efficiency of phenol. The electro-catalytic characteristics were investigated by SEM, the generation amount of hydroxyl radicals, the degradation degree of phenol and the stability and conductivity of the electrodes were also investigated. The experimental results indicate that the four electrodes all show good electro-catalytic characteristics; the electro-catalytic characteristics of the electrode mingled with La were superior to those of the other three ones, and the electrochemical degradation of phenol followed one-step reaction dynamics.
基金supported by the Key Project of National Support Plan from Science and Technology Ministry of China （2006BAC11B06） the Key Project of International Cooperation from the Ministry of Science and Technology of China （2005DFA20800）+1 种基金the Support Plan of National New Century Excellent Youth of China （NCET-04-0286, -05-0398） the Project of National Natural Science Foundation of China （No. 60371035）
文摘With the physical method of micro-gap gas discharge,OH.radicals were producedby the ionization of 02 in air and H_O in the gaseous state,in order to explore more effectivemethod totreat the ship's ballast water.The surface morphology of Al_2O_3 dielectric layer wasanalysed using Atomic Force Microscopy(AFM),where the size of Al_2O3 particles was in the rangeof 2 μm to 5 μm.At the same time,the biochemical effect of hydroxyl radicals on the introducedorganisms and the quality of ship's ballast water were studied.The results indicate that the mainreasons of cell death are lipid peroxide and damage of the antioxidant enzyme system in Catalase(CAT),Peroxidase(POD)and Superoxide dismutase(SOD).In addition,the quality of the ballastwater was greatly improved.
基金This work was supported by the National Natural Science Foundation of China （No.21177041 and No.21107026）, the Fundamental Research Funds for the Central Universities （No.2013ZZ0073）, and the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry.
