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
This study investigated the indirect oxidation of nitrobenzene(NB)by hydroxyl radicals(·OH)in a rotating packed bed(RPB)using competitive kinetics method with p-nitrochlorobenzene as a reference compound.The rate...This study investigated the indirect oxidation of nitrobenzene(NB)by hydroxyl radicals(·OH)in a rotating packed bed(RPB)using competitive kinetics method with p-nitrochlorobenzene as a reference compound.The rate constants of NB with·OH are calculated to be between(1.465±0.113)×10^(9)L/(mol·s)and(2.497±0.192)×10^(9)L/(mol·s).The experimental data are fitted by the modified Arrhenius equation,where the activation energy is 4877.74 J/mol,the order of NB concentration,rotation speed,and initial pH is 0.2425,0.1400 and 0.0167,respectively.The ozonation process of NB could be enhanced by RPB,which is especially effective for highly concentrated NB-containing waste-water under alkaline conditions.The high gravity technology can accelerate ozone mass transfer and self-decomposition of ozone to produce more·OH,resulting in an increase in the indirect oxidation rate of NB by·OH and consequently effective degradation of NB in wastewater.展开更多
<Abstract>In order to explore the production of hydroxyl radical(·OH)in a confined space,a novel ozone-light irradiation system is constructed in this study,and the·OH radical is measured by spin-trapp...<Abstract>In order to explore the production of hydroxyl radical(·OH)in a confined space,a novel ozone-light irradiation system is constructed in this study,and the·OH radical is measured by spin-trapping electron spin resonance(ESR)method in which 5,5-dimethyl-1-pyrroline-N-oxide(DMPO)is selected as the spin-trap.Several influence factors including the light intensity,the irradiation time and DMPO mass concentration are discussed. The results show that in this experimental system,with DMPO mass concentration of 1g/L and the irradiation time of 30 min,the·OH radical can be best captured.Besides,both wavelength and intensity of the irradiation light could effect the generation of·OH radical.These results are of great importance to further study the sterilization effect of·OH radical in confined space.展开更多
Excessive reactive oxygen species(ROS)would attack living cells and cause a series of oxidative stress related diseases,such as liver damage.Hydroxyl radicals(·OH)are currently known as one of the most toxic and ...Excessive reactive oxygen species(ROS)would attack living cells and cause a series of oxidative stress related diseases,such as liver damage.Hydroxyl radicals(·OH)are currently known as one of the most toxic and harmful free radicals to organisms.Therefore,studies involving hydroxyl radicals have become important research topics in the fields of biology,biochemistry,and biomedicine.In addition,imaging of analytes using upconversion nanoparticles(UCNPs)possesses significant advantages over that using general fluorescent dyes or nanoparticles due to its high spatial resolution,reduced photodamage,and deep tissue penetration properties.Herein,we designed a highly selective and sensitive hydroxyl radical nanoprobe based on the luminescence resonance energy transfer between upconversion nanoparticles and methylene blue(MB).The concentration of·OH could be determined by the fluorescence recovery of the UCNPs due to the oxidative damage of MB.Using this nanoprobe,the·OH in living cells or in liver tissues could be monitored with high sensitivity and selectivity.展开更多
Ozonation has been proved to be a promising approach for eliminating emerging pollutants in wastewater.In previous studies,emerging pollutants including diverse pharmaceuticals were found to exhibit significantly diff...Ozonation has been proved to be a promising approach for eliminating emerging pollutants in wastewater.In previous studies,emerging pollutants including diverse pharmaceuticals were found to exhibit significantly different ozonation reactivity.However,how the structural differences of emerging pollutants determine ozonation reactivity and mechanisms are still ambiguous.In this work,ozonation of dimethylaminophenazone(DMP)and acetylaminophenazone(AAA)with the same parent structure of phenazone but different substitution groups was investigated,in order to probe influencing mechanisms of structural differences on ozonation reactivity.Results show that DMP reacts with ozone and HOalmost 2 and 1 order of magnitude faster than AAA,respectively.At pH 8,HO· accelerates ozonation of DMP,but decreases ozonation of AAA.Competition simultaneously decreases degradation rate of the two phenazones,but effects on AAA are more significant than that on DMP.According to theoretical calculation results,differences in ozonation reactivity and mechanisms of the two phenazones can be mainly attributed to different substitution groups.The dimethylamino group in the structure of DMP increases the ozonation reactivity of phenazone by increasing reaction orbital energies and altering reaction sites,while the acetylamino group in the structure of AAA decreases the reaction orbital energy and therefore lowers the reactivity.展开更多
[Objectives]To study the optimum conditions of solid fermentation of natto with antioxidant function as an index.[Methods]Single factor experiment and orthogonal experiment were designed to study the effects of temper...[Objectives]To study the optimum conditions of solid fermentation of natto with antioxidant function as an index.[Methods]Single factor experiment and orthogonal experiment were designed to study the effects of temperature,time,initial pH and inoculum amount on the antioxidant activity of natto solid fermentation.The optimum conditions of natto solid fermentation were determined and the antioxidant ac-tivity of natto extract was compared.[Results]The optimal fermentation conditions were as follows:temperature 32℃,initial pH 7.0,inocu-lation amount 8%,fermentation time 32 h.The hydroxyl radical scavenging rate of natto solid fermentation crude extract was the highest,which was 82.7%.The optimized nato fermentation extract showed stronger scavenging ability for-OH and O,:,and showed obvious dose-effect relationship.ICso was 3.63 and 4.24 mg/mL,respectively,and the scavenging efficiency was 1.3 and 1.9 times higher than that of the unoptimized fermentation extract,respectively.[Conclusions]Natto is rich in nattokinase and other functional factors,and its antioxidant ac-tivity can be improved by optimizing fermentation technology,so that natto products can be widely used,including cosmetic raw materials,nat-to skin care soap,health food and medicine,etc.,and have a broader development prospect.展开更多
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
Selective upgrading of C=O bonds to afford carboxylic acid is significant for the petrochemical industry and biomass utilization.Here we declared the efficient electrooxidation of biomass-derived aldehydes family over...Selective upgrading of C=O bonds to afford carboxylic acid is significant for the petrochemical industry and biomass utilization.Here we declared the efficient electrooxidation of biomass-derived aldehydes family over NiV-layered double hydroxides(LDHs) thin films.Mechanistic studies confirmed the hydroxyl active intermediate(-OH*) generated on the surface of NiV-LDHs films by employing electrochemical impedance spectroscopy and the electron paramagnetic resonance spectroscopy.By using advanced techniques,e.g.,extended X-ray absorption fine structure and high-angle annular dark-field scanning transmission electron microscopy,NiV-LDHs films with 2.6 nm could expose larger specific surface area.Taking benzaldehyde as a model,high current density of 200 mA cm^(-2)at 1.8 V vs.RHE,81.1% conversion,77.6% yield of benzoic acid and 90.8% Faradaic efficiency were reached,which was superior to most of previous studies.Theoretical DFT analysis was well matched with experimental findings and documented that NiV-LDHs had high adsorption capacity for the aldehydes to suppress the side reaction,and the aldehydes were oxidized by the electrophilic hydroxyl radicals formed on NiV-LDHs.Our findings offer a universal strategy for the robust upgrading of diverse biomass-derived platform chemicals.展开更多
[Objectives]To explore the extraction and in vitro antioxidant effects of astragalus polysaccharides(APS)and Ganoderma lucidum mycelia polysaccharides(GLMPS).[Methods]By studying the polysaccharides of the herbal medi...[Objectives]To explore the extraction and in vitro antioxidant effects of astragalus polysaccharides(APS)and Ganoderma lucidum mycelia polysaccharides(GLMPS).[Methods]By studying the polysaccharides of the herbal medicinal material Astragalus membranaceus and the fungal medicinal material Ganoderma lucidum mycelia,two polysaccharides were mixed according to different proportions and concentrations by using the principle of traditional Chinese medicine compound combination.The effect of polysaccharides on the scavenging ability of hydroxyl radical system was determined by salicylic acid method.[Results]When the compound ratios of GLMPS and APS were 1∶1,1∶4,1∶5,4∶1,and 5∶1,the scavenging effect of compound polysaccharides was better than that of single-component polysaccharides,and with the increase of concentration,the scavenging effect increased.When the ratio of GLMPS and APS was 5∶1,the hydroxyl radical scavenging rate of the compound polysaccharide reached 59.77%,which was 18.72%higher than that of single GLMPS and 28.58%higher than that of single APS.The scavenging effect of compound polysaccharide is closely related to the compound ratio and concentration.[Conclusions]APS and GLMPS can obtain better hydroxyl radical scavenging ability than single-component polysaccharides through compounding in appropriate proportions.In addition,within a suitable concentration range,as the concentration increases,the scavenging ability also increases.展开更多
Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions...Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions is still poorly understood.The batch experiments were performed to investigate the effects of estuarine conditions including aging(in air,in water),seawater anions(Cl^(-),Br^(-)and HCO_(3)^(-))and light on the HO^(·)production by pyrite oxidation.The one-electron transfer dominated the process from O_(2) to HO^(·)induced by oxidation of pyrite.The Fe(oxyhydr)oxide coatings on the surface of pyrite aged in air and water consumed hydrogen peroxide while mediating the electron transfer,and the combined effect of the two resulted in a suppression of HO^(·)production in the early stage of aging and a promotion of HO^(·)production in the later stage of aging.Corrosion of the surface oxide layers by aggressive anions was the main reason for the inhibition of HO^(·)production by Cl^(-)and Br^(-),and the generation of Cl^(·)and Br^(·)may also play a role in the scavenging of HO^(·).HCO_(3)^(-)increased the average rate of HO^(·)production through surface-CO_(2) complexes formed by adsorption on the surface of pyrite.The significant enhancement of HO^(·)production under light was attributed to the formation of photoelectrons induced by photochemical reactions on pyrite and its surface oxide layers.These findings provide new insights into the environmental chemical behavior of pyrite in the estuary and enrich the understanding of natural remediation of estuarine environments.展开更多
The discharge of the antibiotic wastewater has increased dramatically in our country with the development of medical science and wide application of antibiotic,resulting in serious harm to human body and ecological en...The discharge of the antibiotic wastewater has increased dramatically in our country with the development of medical science and wide application of antibiotic,resulting in serious harm to human body and ecological environment.In this work,ciprofloxacin(CIP)was selected as one of typical antibiotics and heterogeneous Fenton-like catalysts were prepared for the treatment of ciprofloxacin wastewater.The sodium alginate(SA)gel microspheres catalysts were prepared by polymerization method using double metal ions of Fe^(3+)and Mn^(2+)as cross-linking agents.Preparation conditions such as metal ions concentration,mass fraction of SA,polymerization temperature and dual-metal ions as crosslinking agent were optimized.Moreover,the effects of operating conditions such as initial concentration of CIP,pH value and catalyst dosage on CIP removal were studied.The kinetic equation showed that the effect of the initial concentration of CIP on the degradation rate was in line with second-order kinetics,and the effects of catalyst dosage and pH value on the degradation rate of CIP were in line with first-order kinetics.The SA gel microspheres catalysts prepared by dual-metal ions exhibited a high CIP removal and showed a good reusability after six recycles.The SA gel microspheres catalysts with an easy recovery performance provided an economical and efficient method for the removal of antibiotics in the future.展开更多
Hydrodynamic cavitation is considered to be a promising technology for process intensification,due to its high energy efficiency,cost-effective operation,ability to induce chemical reactions,and scale-up possibilities...Hydrodynamic cavitation is considered to be a promising technology for process intensification,due to its high energy efficiency,cost-effective operation,ability to induce chemical reactions,and scale-up possibilities.In the past decade,advancements have been made in the fundamental understanding of hydrodynamic cavitation and its main variables,which provide a basis for applications of hydrodynamic cavitation in radical-induced chemical reaction processes.Here,we provide an extensive review of these research efforts,including the fundamentals of hydrodynamic cavitation,the design of cavitation reactors,cavitation-induced reaction enhancement,and relevant industrial applications.Two types of hydrodynamic cavitation reactors—namely,stationary and rotational—are compared.The design parameters of a hydrodynamic cavitation reactor and reactor performance at the laboratory and pilot scales are discussed,and recommendations are made regarding optimal operation and geometric conditions.The commercial cavitation reactors that are currently on the market are reviewed here for the first time.The unique features of hydrodynamic cavitation have been widely applied to various chemical reactions,such as oxidization reactions and wastewater treatment,and to physical processes,such as emulsion generation and component extraction.The roles of radicals and gas bubble implosion are also thoroughly discussed.展开更多
The effects of Humic Acid (HA) concentration,pH value and aeration on the photocatalysis degradation of HA by the silica gel supported TiO2 were studied.Moreover,the effect of aeration on the generation of hydroxyl ra...The effects of Humic Acid (HA) concentration,pH value and aeration on the photocatalysis degradation of HA by the silica gel supported TiO2 were studied.Moreover,the effect of aeration on the generation of hydroxyl radicals are investigated.The experimental results indicated that the hydroxyl radicals are generated during the photocatalysis process.The generation of hydroxyl radicals is increasing linearly with the reaction time,approximately.Moreover,the generation rate of hydroxyl under the condition of aeration is 1.57 times of that under the condition without aeration,which is the main influent factor on the reaction rate.Therefore,the reaction rate constant with and without aeration is 0.012 min-1 and 0.0063 min-1,respectively.The degradation rate decreases when the initial HA concentration increases,which is due to that more TiO2 active sites are occupied by HA when the HA concentration is higher.Moreover,HA can absorb large amount of photons,which can prevent those available photons to arrive at the activate TiO2 particles.The degradation rate decreases when increasing pH value,which is due to that the adsorption of HA on the TiO2 particles is weakened and not benefit for the degradation process of HA.展开更多
The Electro-Fenton(EF)process is one of the promising advanced oxidation processes(AOPs)for environmental remediation.The H_(2)O_(2) yield of EF process largely determines its performance on organic pollutants degrada...The Electro-Fenton(EF)process is one of the promising advanced oxidation processes(AOPs)for environmental remediation.The H_(2)O_(2) yield of EF process largely determines its performance on organic pollutants degradation.Conventional Pd-catalytic EF process generates H_(2)O_(2) via the combination reaction of anodic O_(2) and cathodic H;.However,the relatively expensive catalyst limits its application.Herein,a hybrid Pd/activated carbon(Pd/AC)-stainless steel mesh(SS)cathode(PACSS)was proposed,which enables more efficie nt H_(2)O_(2)generation.It utilizes AC,the support of Pd catalyst,as part of cathode for H_(2)O_(2) generation via 2-electron anodic O_(2) reduction,and SS serve as a current distributor.Moreover,H_(2)O_(2) could be catalytically decomposed upon AC to generate highly reactive·OH,which avoids the use of Fe;.Compared with conventional Pd catalyst,H_(2)O_(2) concentration obtained by PACSS cathode is248.2%higher,the O_(2)utilization efficiency was also increased from 3.2%to 10.8%.Within 50 min,26.3%,72.5%,and 94.0%H_(2)O_(2) was decomposed by Pd,AC,and Pd/AC.Fluorescence detection results implied that Pd/AC is effective upon H_(2)O_(2) activation for·OH generation.Finally,iron-free EF process enabled by PACSS cathode was examined to be effective for reactive blue 19(RB19)degradation.After continuous running for 10 cycles(500 min),the PACSS cathode was still stable for H_(2)O_(2)generation,H_(2)O_(2)activation,and RB19 degradation,showing its potential application for organic pollutants degradation without increase in the running cost.展开更多
AIM: To study the mechanism underlying carbon tetrachloride (CCl4)-induced alterations of protein synthesis in liver. METHODS: Male Sprague-Dawley rats were given CCl4 (1 mL/100 g body weight) and 3H-leucine incorpora...AIM: To study the mechanism underlying carbon tetrachloride (CCl4)-induced alterations of protein synthesis in liver. METHODS: Male Sprague-Dawley rats were given CCl4 (1 mL/100 g body weight) and 3H-leucine incorporation. Malondialdehyde (MDA) level in the liver, in vitro response of hepatocyte nuclei nucleotide triphosphatase (NTPase) to free radicals, and nuclear export of total mRNA with 3'-poly A+ were measured respectively. Survival response of HepG2 cells to CCl4 treatment was assessed by methyl thiazolyl tetrazolium. Km and Vmax values of nuclear envelope NTPase activity in liver of rats treated with CCl4 were assayed by a double-reciprocal plot. RESULTS: The protein synthesis was inhibited while the MDA level was signif icantly increased in liver of rats treated with CCl4. In addition, CCl4 decreased the NTPase binding capacity of nuclear envelope (Km value) in cultured HepG2 cells. Moreover, in vitro ferrous radicals from Fenton's system suppressed the NTPase activity of liver nuclear envelope in a dose-dependent manner. Down-regulation of the nuclear envelope NTPase activity indicated a lower energy provision for nucleocytoplasmic transport of mRNA molecules, an evidence in CCl4-treated HepG2 cells correspondingly supported by the nuclear sequestration of poly (A)+ mRNA molecules in morphological hybridization research. CONCLUSION: Inhibition of mRNA transport, suggestive of decreased NTPase activity of the nuclear envelope, may be involved in carbon tetrachloride-inhibited protein synthesis in liver.展开更多
The hydroxyl radical(·OH)has a crucial function in the oxidation and removal of many atmospheric compounds that are harmful to health.Nevertheless,high reactivity,low atmospheric abundance,determination of hydrox...The hydroxyl radical(·OH)has a crucial function in the oxidation and removal of many atmospheric compounds that are harmful to health.Nevertheless,high reactivity,low atmospheric abundance,determination of hydroxyl,and hydroperoxyl radical’s quantity is very difficult.In the atmosphere and troposphere,hydroperoxyl radicals(HO_(2))are closely demanded in the chemical oxidation of the troposphere.But advances in technology have allowed researchers to improve the determination methods on the research of free radicals through some spectroscopic techniques.So far,several methods such as laser-induced fluorescence(LIF),high-performance liquid chromatography(HPLC),and chemical ionization mass spectroscopy have been identified and mostly used in determining the quantity of hydroxyl and hydroperoxyl radicals.In this systematic review,we have advised the use of scavenger as an advance for further researchers to circumvent some of these problems caused by free radicals.The primary goal of this review is to deepen our understanding of the functions of the most critical free radical(·OH,HO_(2))and also understand the currently used methods to quantify them in the atmosphere and troposphere.展开更多
The sluggish kinetics of Fe(Ⅱ)recovery in Fenton/Fenton-like reactions significantly limits the oxidation efficiency.In this study,we for the first time use boron carbide(BC)as a green and stable promotor to enhance ...The sluggish kinetics of Fe(Ⅱ)recovery in Fenton/Fenton-like reactions significantly limits the oxidation efficiency.In this study,we for the first time use boron carbide(BC)as a green and stable promotor to enhance the reaction of Fe(Ⅲ)/H_(2)O_(2) for degradation of diverse organic pollutants.Electron paramagnetic resonance analysis and chemical quenching/capturing experiments demonstrate that hydroxyl radicals(·OH)are the primary reactive species in the BC/Fe(Ⅲ)/H_(2)O_(2) system.In situ electrochemical analysis indicates that BC remarkably boosts the Fe(Ⅲ)/Fe(Ⅱ)redox cycles,where the adsorbed Fe(Ⅲ)cations were transformed to more active Fe(Ⅲ)species with a higher oxidative potential to react with H_(2)O_(2) to produce Fe(Ⅱ).Thus,the recovery of Fe(Ⅱ)from Fe(Ⅲ)is facilitated over BC surface,which enhancesOH generation via Fenton reactions.Moreover,BC exhibits outstanding reusability and stability in successive cycles and avoids the secondary pollution caused by conventional organic and metalliferous promotors.Therefore,metal-free BC boosting Fe(Ⅲ)/H_(2)O_(2) oxidation of organics provides a green and advanced strategy for water decontamination.展开更多
Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively....Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively. It was found thatβ-alanine C60 adducts showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50% inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.15 mg/mL and 0.048 mg/mL, respectively. The difference should be mainly attributed to the different scavenging mechanisms.展开更多
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the Specialized Research Fund for Sanjin Scholars Program of Shanxi Province(No.201707)Key Research&Development Plan of Shanxi Province(No.201903D321059)+1 种基金Shanxi Scholarship Council of China(No.HGKY2019071)Transformation and Cultivation Projects of Scientific and Technological Achievements of Higher Education Institutions for Shanxi Province(No.2020CG040).
文摘This study investigated the indirect oxidation of nitrobenzene(NB)by hydroxyl radicals(·OH)in a rotating packed bed(RPB)using competitive kinetics method with p-nitrochlorobenzene as a reference compound.The rate constants of NB with·OH are calculated to be between(1.465±0.113)×10^(9)L/(mol·s)and(2.497±0.192)×10^(9)L/(mol·s).The experimental data are fitted by the modified Arrhenius equation,where the activation energy is 4877.74 J/mol,the order of NB concentration,rotation speed,and initial pH is 0.2425,0.1400 and 0.0167,respectively.The ozonation process of NB could be enhanced by RPB,which is especially effective for highly concentrated NB-containing waste-water under alkaline conditions.The high gravity technology can accelerate ozone mass transfer and self-decomposition of ozone to produce more·OH,resulting in an increase in the indirect oxidation rate of NB by·OH and consequently effective degradation of NB in wastewater.
文摘<Abstract>In order to explore the production of hydroxyl radical(·OH)in a confined space,a novel ozone-light irradiation system is constructed in this study,and the·OH radical is measured by spin-trapping electron spin resonance(ESR)method in which 5,5-dimethyl-1-pyrroline-N-oxide(DMPO)is selected as the spin-trap.Several influence factors including the light intensity,the irradiation time and DMPO mass concentration are discussed. The results show that in this experimental system,with DMPO mass concentration of 1g/L and the irradiation time of 30 min,the·OH radical can be best captured.Besides,both wavelength and intensity of the irradiation light could effect the generation of·OH radical.These results are of great importance to further study the sterilization effect of·OH radical in confined space.
基金the support from the National Natural Science Foundation of China(21601046,31500812,and 21603051)the Natural Science Foundation of Hebei Province(B2016201169,B2017201226,B2018201221,and B2018201157)+2 种基金Key Projects of Education Department of Hebei Province(ZD2018036)the Foundation for Returned Overseas Chinese Scholars of Hebei Province(CY201703)Hebei Youth Top Talent Project.
文摘Excessive reactive oxygen species(ROS)would attack living cells and cause a series of oxidative stress related diseases,such as liver damage.Hydroxyl radicals(·OH)are currently known as one of the most toxic and harmful free radicals to organisms.Therefore,studies involving hydroxyl radicals have become important research topics in the fields of biology,biochemistry,and biomedicine.In addition,imaging of analytes using upconversion nanoparticles(UCNPs)possesses significant advantages over that using general fluorescent dyes or nanoparticles due to its high spatial resolution,reduced photodamage,and deep tissue penetration properties.Herein,we designed a highly selective and sensitive hydroxyl radical nanoprobe based on the luminescence resonance energy transfer between upconversion nanoparticles and methylene blue(MB).The concentration of·OH could be determined by the fluorescence recovery of the UCNPs due to the oxidative damage of MB.Using this nanoprobe,the·OH in living cells or in liver tissues could be monitored with high sensitivity and selectivity.
基金supported by the National High Technology Research and Development of China(No.2013AA06A305)Program for Changjiang Scholars and Innovative Research Team in University,China Postdoctoral Science Foundation(2013T60128)Hundreds Talents Program of Chinese Academy of Sciences.
文摘Ozonation has been proved to be a promising approach for eliminating emerging pollutants in wastewater.In previous studies,emerging pollutants including diverse pharmaceuticals were found to exhibit significantly different ozonation reactivity.However,how the structural differences of emerging pollutants determine ozonation reactivity and mechanisms are still ambiguous.In this work,ozonation of dimethylaminophenazone(DMP)and acetylaminophenazone(AAA)with the same parent structure of phenazone but different substitution groups was investigated,in order to probe influencing mechanisms of structural differences on ozonation reactivity.Results show that DMP reacts with ozone and HOalmost 2 and 1 order of magnitude faster than AAA,respectively.At pH 8,HO· accelerates ozonation of DMP,but decreases ozonation of AAA.Competition simultaneously decreases degradation rate of the two phenazones,but effects on AAA are more significant than that on DMP.According to theoretical calculation results,differences in ozonation reactivity and mechanisms of the two phenazones can be mainly attributed to different substitution groups.The dimethylamino group in the structure of DMP increases the ozonation reactivity of phenazone by increasing reaction orbital energies and altering reaction sites,while the acetylamino group in the structure of AAA decreases the reaction orbital energy and therefore lowers the reactivity.
基金Supported by 2023 Zhanjiang Non-funded Science and Technology Research Plan(2023B01023)2022 University-level Education and Teaching Reform Project of Lingnan Normal University(LingShiJiaoWu2022154).Junxia SONG,bachelor degree,experimenter,research fields:physical geography.
文摘[Objectives]To study the optimum conditions of solid fermentation of natto with antioxidant function as an index.[Methods]Single factor experiment and orthogonal experiment were designed to study the effects of temperature,time,initial pH and inoculum amount on the antioxidant activity of natto solid fermentation.The optimum conditions of natto solid fermentation were determined and the antioxidant ac-tivity of natto extract was compared.[Results]The optimal fermentation conditions were as follows:temperature 32℃,initial pH 7.0,inocu-lation amount 8%,fermentation time 32 h.The hydroxyl radical scavenging rate of natto solid fermentation crude extract was the highest,which was 82.7%.The optimized nato fermentation extract showed stronger scavenging ability for-OH and O,:,and showed obvious dose-effect relationship.ICso was 3.63 and 4.24 mg/mL,respectively,and the scavenging efficiency was 1.3 and 1.9 times higher than that of the unoptimized fermentation extract,respectively.[Conclusions]Natto is rich in nattokinase and other functional factors,and its antioxidant ac-tivity can be improved by optimizing fermentation technology,so that natto products can be widely used,including cosmetic raw materials,nat-to skin care soap,health food and medicine,etc.,and have a broader development prospect.
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.
基金supported by the National Natural Science Foundation of China(22078374,21776324)the Scientific and Technological Planning Project of Guangzhou(202206010145)+2 种基金the National Ten Thousand Talent Plan,Key-Area Research and Development Program of Guangdong Province(2019B110209003)the Guangdong Basic and Applied Basic Research Foundation(2019B1515120058,2020A1515011149)the Start-up Fund for Senior Talents in Jiangsu University(21JDG060)。
文摘Selective upgrading of C=O bonds to afford carboxylic acid is significant for the petrochemical industry and biomass utilization.Here we declared the efficient electrooxidation of biomass-derived aldehydes family over NiV-layered double hydroxides(LDHs) thin films.Mechanistic studies confirmed the hydroxyl active intermediate(-OH*) generated on the surface of NiV-LDHs films by employing electrochemical impedance spectroscopy and the electron paramagnetic resonance spectroscopy.By using advanced techniques,e.g.,extended X-ray absorption fine structure and high-angle annular dark-field scanning transmission electron microscopy,NiV-LDHs films with 2.6 nm could expose larger specific surface area.Taking benzaldehyde as a model,high current density of 200 mA cm^(-2)at 1.8 V vs.RHE,81.1% conversion,77.6% yield of benzoic acid and 90.8% Faradaic efficiency were reached,which was superior to most of previous studies.Theoretical DFT analysis was well matched with experimental findings and documented that NiV-LDHs had high adsorption capacity for the aldehydes to suppress the side reaction,and the aldehydes were oxidized by the electrophilic hydroxyl radicals formed on NiV-LDHs.Our findings offer a universal strategy for the robust upgrading of diverse biomass-derived platform chemicals.
基金Supported by the Project of"Striving to Be First-classImproving Weak LinksBuilding Strong Feature"in 2019–Tropical and South China Sea Biological Resources Comprehensive Utilization Program(000301900410)。
文摘[Objectives]To explore the extraction and in vitro antioxidant effects of astragalus polysaccharides(APS)and Ganoderma lucidum mycelia polysaccharides(GLMPS).[Methods]By studying the polysaccharides of the herbal medicinal material Astragalus membranaceus and the fungal medicinal material Ganoderma lucidum mycelia,two polysaccharides were mixed according to different proportions and concentrations by using the principle of traditional Chinese medicine compound combination.The effect of polysaccharides on the scavenging ability of hydroxyl radical system was determined by salicylic acid method.[Results]When the compound ratios of GLMPS and APS were 1∶1,1∶4,1∶5,4∶1,and 5∶1,the scavenging effect of compound polysaccharides was better than that of single-component polysaccharides,and with the increase of concentration,the scavenging effect increased.When the ratio of GLMPS and APS was 5∶1,the hydroxyl radical scavenging rate of the compound polysaccharide reached 59.77%,which was 18.72%higher than that of single GLMPS and 28.58%higher than that of single APS.The scavenging effect of compound polysaccharide is closely related to the compound ratio and concentration.[Conclusions]APS and GLMPS can obtain better hydroxyl radical scavenging ability than single-component polysaccharides through compounding in appropriate proportions.In addition,within a suitable concentration range,as the concentration increases,the scavenging ability also increases.
基金supported by the National Natural Science Foundation of China (No.51709157)the Youth Interdisciplinary Science and Innovative Research Groups of Shandong University (No.2020QNQT014)。
文摘Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions is still poorly understood.The batch experiments were performed to investigate the effects of estuarine conditions including aging(in air,in water),seawater anions(Cl^(-),Br^(-)and HCO_(3)^(-))and light on the HO^(·)production by pyrite oxidation.The one-electron transfer dominated the process from O_(2) to HO^(·)induced by oxidation of pyrite.The Fe(oxyhydr)oxide coatings on the surface of pyrite aged in air and water consumed hydrogen peroxide while mediating the electron transfer,and the combined effect of the two resulted in a suppression of HO^(·)production in the early stage of aging and a promotion of HO^(·)production in the later stage of aging.Corrosion of the surface oxide layers by aggressive anions was the main reason for the inhibition of HO^(·)production by Cl^(-)and Br^(-),and the generation of Cl^(·)and Br^(·)may also play a role in the scavenging of HO^(·).HCO_(3)^(-)increased the average rate of HO^(·)production through surface-CO_(2) complexes formed by adsorption on the surface of pyrite.The significant enhancement of HO^(·)production under light was attributed to the formation of photoelectrons induced by photochemical reactions on pyrite and its surface oxide layers.These findings provide new insights into the environmental chemical behavior of pyrite in the estuary and enrich the understanding of natural remediation of estuarine environments.
基金supported by the National Natural Science Foundation of China(22125802 and 22108012)Natural Science Foundation of Beijing Municipality(2222017)Fundamental Research Funds for the Central Universities(BUCTRC-202109)。
文摘The discharge of the antibiotic wastewater has increased dramatically in our country with the development of medical science and wide application of antibiotic,resulting in serious harm to human body and ecological environment.In this work,ciprofloxacin(CIP)was selected as one of typical antibiotics and heterogeneous Fenton-like catalysts were prepared for the treatment of ciprofloxacin wastewater.The sodium alginate(SA)gel microspheres catalysts were prepared by polymerization method using double metal ions of Fe^(3+)and Mn^(2+)as cross-linking agents.Preparation conditions such as metal ions concentration,mass fraction of SA,polymerization temperature and dual-metal ions as crosslinking agent were optimized.Moreover,the effects of operating conditions such as initial concentration of CIP,pH value and catalyst dosage on CIP removal were studied.The kinetic equation showed that the effect of the initial concentration of CIP on the degradation rate was in line with second-order kinetics,and the effects of catalyst dosage and pH value on the degradation rate of CIP were in line with first-order kinetics.The SA gel microspheres catalysts prepared by dual-metal ions exhibited a high CIP removal and showed a good reusability after six recycles.The SA gel microspheres catalysts with an easy recovery performance provided an economical and efficient method for the removal of antibiotics in the future.
基金The authors are grateful for the financial support provided by the Natural Sciences and Engineering Research Council of Canada(RGPIN_2019-06614).
文摘Hydrodynamic cavitation is considered to be a promising technology for process intensification,due to its high energy efficiency,cost-effective operation,ability to induce chemical reactions,and scale-up possibilities.In the past decade,advancements have been made in the fundamental understanding of hydrodynamic cavitation and its main variables,which provide a basis for applications of hydrodynamic cavitation in radical-induced chemical reaction processes.Here,we provide an extensive review of these research efforts,including the fundamentals of hydrodynamic cavitation,the design of cavitation reactors,cavitation-induced reaction enhancement,and relevant industrial applications.Two types of hydrodynamic cavitation reactors—namely,stationary and rotational—are compared.The design parameters of a hydrodynamic cavitation reactor and reactor performance at the laboratory and pilot scales are discussed,and recommendations are made regarding optimal operation and geometric conditions.The commercial cavitation reactors that are currently on the market are reviewed here for the first time.The unique features of hydrodynamic cavitation have been widely applied to various chemical reactions,such as oxidization reactions and wastewater treatment,and to physical processes,such as emulsion generation and component extraction.The roles of radicals and gas bubble implosion are also thoroughly discussed.
基金Sponsored by the Fundamental Research Funds for the Central Universities (Grant No. 2009BO1614)the Ministry of Water Resources' Special Funds for Scientific Research on Public Causes(Grant No. 201101052)the Natural Found of Hohai University(Grant No. 2009423311)
文摘The effects of Humic Acid (HA) concentration,pH value and aeration on the photocatalysis degradation of HA by the silica gel supported TiO2 were studied.Moreover,the effect of aeration on the generation of hydroxyl radicals are investigated.The experimental results indicated that the hydroxyl radicals are generated during the photocatalysis process.The generation of hydroxyl radicals is increasing linearly with the reaction time,approximately.Moreover,the generation rate of hydroxyl under the condition of aeration is 1.57 times of that under the condition without aeration,which is the main influent factor on the reaction rate.Therefore,the reaction rate constant with and without aeration is 0.012 min-1 and 0.0063 min-1,respectively.The degradation rate decreases when the initial HA concentration increases,which is due to that more TiO2 active sites are occupied by HA when the HA concentration is higher.Moreover,HA can absorb large amount of photons,which can prevent those available photons to arrive at the activate TiO2 particles.The degradation rate decreases when increasing pH value,which is due to that the adsorption of HA on the TiO2 particles is weakened and not benefit for the degradation process of HA.
基金financially supported by the National Natural Science Foundation of China(Nos.52006049,51776055)the China Postdoctoral Science Foundation(Nos.2019M661293,2020T130149)。
文摘The Electro-Fenton(EF)process is one of the promising advanced oxidation processes(AOPs)for environmental remediation.The H_(2)O_(2) yield of EF process largely determines its performance on organic pollutants degradation.Conventional Pd-catalytic EF process generates H_(2)O_(2) via the combination reaction of anodic O_(2) and cathodic H;.However,the relatively expensive catalyst limits its application.Herein,a hybrid Pd/activated carbon(Pd/AC)-stainless steel mesh(SS)cathode(PACSS)was proposed,which enables more efficie nt H_(2)O_(2)generation.It utilizes AC,the support of Pd catalyst,as part of cathode for H_(2)O_(2) generation via 2-electron anodic O_(2) reduction,and SS serve as a current distributor.Moreover,H_(2)O_(2) could be catalytically decomposed upon AC to generate highly reactive·OH,which avoids the use of Fe;.Compared with conventional Pd catalyst,H_(2)O_(2) concentration obtained by PACSS cathode is248.2%higher,the O_(2)utilization efficiency was also increased from 3.2%to 10.8%.Within 50 min,26.3%,72.5%,and 94.0%H_(2)O_(2) was decomposed by Pd,AC,and Pd/AC.Fluorescence detection results implied that Pd/AC is effective upon H_(2)O_(2) activation for·OH generation.Finally,iron-free EF process enabled by PACSS cathode was examined to be effective for reactive blue 19(RB19)degradation.After continuous running for 10 cycles(500 min),the PACSS cathode was still stable for H_(2)O_(2)generation,H_(2)O_(2)activation,and RB19 degradation,showing its potential application for organic pollutants degradation without increase in the running cost.
基金Supported by The National Natural Science Foundation of China,No.30470846
文摘AIM: To study the mechanism underlying carbon tetrachloride (CCl4)-induced alterations of protein synthesis in liver. METHODS: Male Sprague-Dawley rats were given CCl4 (1 mL/100 g body weight) and 3H-leucine incorporation. Malondialdehyde (MDA) level in the liver, in vitro response of hepatocyte nuclei nucleotide triphosphatase (NTPase) to free radicals, and nuclear export of total mRNA with 3'-poly A+ were measured respectively. Survival response of HepG2 cells to CCl4 treatment was assessed by methyl thiazolyl tetrazolium. Km and Vmax values of nuclear envelope NTPase activity in liver of rats treated with CCl4 were assayed by a double-reciprocal plot. RESULTS: The protein synthesis was inhibited while the MDA level was signif icantly increased in liver of rats treated with CCl4. In addition, CCl4 decreased the NTPase binding capacity of nuclear envelope (Km value) in cultured HepG2 cells. Moreover, in vitro ferrous radicals from Fenton's system suppressed the NTPase activity of liver nuclear envelope in a dose-dependent manner. Down-regulation of the nuclear envelope NTPase activity indicated a lower energy provision for nucleocytoplasmic transport of mRNA molecules, an evidence in CCl4-treated HepG2 cells correspondingly supported by the nuclear sequestration of poly (A)+ mRNA molecules in morphological hybridization research. CONCLUSION: Inhibition of mRNA transport, suggestive of decreased NTPase activity of the nuclear envelope, may be involved in carbon tetrachloride-inhibited protein synthesis in liver.
基金the National Key R&D Program of China(No.2016YFC0202900)the National Natural Science Foundation of China(Nos.21567015 and 21407072)+5 种基金the West Light Foundation of The Chinese Academy of Sciences(2019)special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control(No.20K03ESPCP)the Natural Science Foundation of Gansu Province(Nos.18JR3RA079 and 17JR5RA109)the Project of Food and Drug Administration of Gansu Province(No.2018GSFDA014)the Gansu Provincial Party Committee Young Creative Talents(No.Ganzutongzi[2017]121)the Hongliu Science Fund for Distinguished Young Scholars(2018)。
文摘The hydroxyl radical(·OH)has a crucial function in the oxidation and removal of many atmospheric compounds that are harmful to health.Nevertheless,high reactivity,low atmospheric abundance,determination of hydroxyl,and hydroperoxyl radical’s quantity is very difficult.In the atmosphere and troposphere,hydroperoxyl radicals(HO_(2))are closely demanded in the chemical oxidation of the troposphere.But advances in technology have allowed researchers to improve the determination methods on the research of free radicals through some spectroscopic techniques.So far,several methods such as laser-induced fluorescence(LIF),high-performance liquid chromatography(HPLC),and chemical ionization mass spectroscopy have been identified and mostly used in determining the quantity of hydroxyl and hydroperoxyl radicals.In this systematic review,we have advised the use of scavenger as an advance for further researchers to circumvent some of these problems caused by free radicals.The primary goal of this review is to deepen our understanding of the functions of the most critical free radical(·OH,HO_(2))and also understand the currently used methods to quantify them in the atmosphere and troposphere.
基金support to visit The University of Adelaide from the China Scholarship Council(No.201906240037).
文摘The sluggish kinetics of Fe(Ⅱ)recovery in Fenton/Fenton-like reactions significantly limits the oxidation efficiency.In this study,we for the first time use boron carbide(BC)as a green and stable promotor to enhance the reaction of Fe(Ⅲ)/H_(2)O_(2) for degradation of diverse organic pollutants.Electron paramagnetic resonance analysis and chemical quenching/capturing experiments demonstrate that hydroxyl radicals(·OH)are the primary reactive species in the BC/Fe(Ⅲ)/H_(2)O_(2) system.In situ electrochemical analysis indicates that BC remarkably boosts the Fe(Ⅲ)/Fe(Ⅱ)redox cycles,where the adsorbed Fe(Ⅲ)cations were transformed to more active Fe(Ⅲ)species with a higher oxidative potential to react with H_(2)O_(2) to produce Fe(Ⅱ).Thus,the recovery of Fe(Ⅱ)from Fe(Ⅲ)is facilitated over BC surface,which enhancesOH generation via Fenton reactions.Moreover,BC exhibits outstanding reusability and stability in successive cycles and avoids the secondary pollution caused by conventional organic and metalliferous promotors.Therefore,metal-free BC boosting Fe(Ⅲ)/H_(2)O_(2) oxidation of organics provides a green and advanced strategy for water decontamination.
文摘Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively. It was found thatβ-alanine C60 adducts showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50% inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.15 mg/mL and 0.048 mg/mL, respectively. The difference should be mainly attributed to the different scavenging mechanisms.