A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol （2-CP） and 4-chlorophenol （4-CP） were prepared, and the supported CuO catalysts were studied particularly. The supported CuO ...A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol （2-CP） and 4-chlorophenol （4-CP） were prepared, and the supported CuO catalysts were studied particularly. The supported CuO catalysts were characterized by XRD and NH3-TPD techniques, in which CuO/γ-Al2O3 exhibited high degradation activity. The addition of Na2O or K2O into CuO/γ-Al2O3 improved the oxidative degradation of CPs remarkably, in which Na2O was more efficient than K2O. Over CuO/γ-Al2O3-Na2O, CPs were completely converted and the liberation of the inorganic chloride from 2-CP or 4-CP reached 97% or 100% respectively at 30 ？C for 2 h. The supported CuO catalysts with good dispersion of CuO particles and less acid sites were favorable for the efficient oxidative degradation of CPs. In addition, the initial pH of the reaction solution was found to be an important factor which influenced the catalytic oxidative degradation of CPs and the initial pH of 11.2 and 9.8 was preferred for the oxidative degradation of 2-CP and 4-CP respectively over CuO/γ-Al2O3 catalyst.展开更多
The extensive use of tetracycline hydrochloride(TCH)poses a threat to human health and the aquatic environment.Here,magnetic p-n Bi2WO6/CuFe2O4 catalyst was fabricated to efficiently remove TCH.The obtained Bi2WO6/CuF...The extensive use of tetracycline hydrochloride(TCH)poses a threat to human health and the aquatic environment.Here,magnetic p-n Bi2WO6/CuFe2O4 catalyst was fabricated to efficiently remove TCH.The obtained Bi2WO6/CuFe2O4 exhibited 92.1%TCH degradation efficiency and 50.7%and 35.1%mineralization performance for TCH and raw secondary effluent from a wastewater treatment plant in a photo-Fenton-like system,respectively.The remarkable performance was attributed to the fact that photogenerated electrons accelerated the Fe(III)/Fe(II)and Cu(II)/Cu(I)conversion for the Fenton-like reaction between Fe(II)/Cu(I)and H2O2,thereby generating abundant·OH for pollutant oxidation.Various environmental factors including H2O2 concentration,initial pH,catalyst dosage,TCH concentration and inorganic ions were explored.The reactive oxidation species(ROS)quenching results and electron spin resonance(ESR)spectra confirmed that·O2-and·OH were responsible for the dark and photo-Fenton-like systems,respectively.The degradation mechanisms and pathways of TCH were proposed,and the toxicity of products was evaluated.This work contributes a highly efficient and environmentally friendly catalyst and provides a clear mechanistic explanation for the removal of antibiotic pollutants in environmental remediation.展开更多
The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented ...The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H 2O 2/UV has beneficial effect on mineralization than O 3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.展开更多
The development of new catalytic techniques for wastewater treatment has long attracted much attention from industrial and academic communities.However,because of catalyst leaching during degradation,catalysts can be ...The development of new catalytic techniques for wastewater treatment has long attracted much attention from industrial and academic communities.However,because of catalyst leaching during degradation,catalysts can be short lived,and therefore expensive,and unsuitable for use in wastewater treatment.In this work,we developed a bimetallic CuO-Co3O4@γ-Al2O3 catalyst for phenol degradation with bicarbonate-activated H2O2.The weakly basic environment provided by the bicarbonate buffer greatly suppresses leaching of active Cu and Co metal ions from the catalyst.X-ray diffraction and X-ray photoelectron spectroscopy results showed interactions between Cu and Co ions in the CuO-Co3O4@γ-Al2O3 catalyst,and these improve the catalytic activity in phenol degradation.Mechanistic studies using different radical scavengers showed that superoxide and hydroxyl radicals both played significant roles in phenol degradation,whereas singlet oxygen was less important.展开更多
Highly ordered Cu2O coated silicon nanowire arrays （SiNWAs） were fabricated as photocatalyst via depositing Cu nanoparticles on silver-assisted electroless-etched SiNWAs and subsequently annealing. The as-prepared s...Highly ordered Cu2O coated silicon nanowire arrays （SiNWAs） were fabricated as photocatalyst via depositing Cu nanoparticles on silver-assisted electroless-etched SiNWAs and subsequently annealing. The as-prepared samples have been characterized by scanning electron microscopy, X-ray diffraction and UV-VIS-NIR spectrophotometry. The photocatalytic properties of the Cu2O coated SiNWAs were investigated by degradation of Rhodamine B （RhB） under simulated solar light with a cut-off filter （λ 〉 420 nm）. The results indicated that H2O2 could greatly improve the photocatalytic properties of Cu2O coated SiNWAs, and exhibited strong synergy effect between them. The hybrid nanowire arrays will be promising photocatalytic materials in the field of energy and environment.展开更多
The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results sh...The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.展开更多
An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals.Various substituted toluenes（NO2,Cl,Br,H,CH3） were high selectively ...An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals.Various substituted toluenes（NO2,Cl,Br,H,CH3） were high selectively brominated at the benzyl position for monobromination in CH2C12 at ice water with catalyst free.This simple but effective bromination of toluene derivatives with an aqueous H2O2-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.展开更多
Fe3O4 magnetic nanoparticles(MNPs) were synthesised, characterised, and used as a peroxidase mimetic to accelerate levofloxacin sono-degradation in an ultrasound(US)/H2O2 system. The Fe3O4 MNPs were in nanometre scale...Fe3O4 magnetic nanoparticles(MNPs) were synthesised, characterised, and used as a peroxidase mimetic to accelerate levofloxacin sono-degradation in an ultrasound(US)/H2O2 system. The Fe3O4 MNPs were in nanometre scale with an average diameter of approximately 12 to 18 nm. The introduction of Fe3O4 MNPs increased levofloxacin sono-degradation in the US/H2O2 system. Experimental parameters, such as Fe3O4 MNP dose, initial solution p H, and H2O2 concentration, were investigated by a one-factor-at-a-time approach. The results showed that Fe3O4 MNPs enhanced levofloxacin removal in the p H range from 4.0 to 9.0. Levofloxacin removal ratio increased with Fe3O4 MNP dose up to 1.0 g·L-1and with H2O2 concentration until reaching the maximum. Moreover, three main intermediate compounds were identified by HPLC with electrospray ionisation tandem mass spectrometry, and a possible degradation pathway was proposed. This study suggests that combination of H2O2, Fe3O4 MNPs and US is a good way to improve the degradation efficiency of antibiotics.展开更多
Rho kinase （ROCK） was the first downstream Rho effector found to mediate RhoA-induced actin cytoskeletal changes through effects on myosin light chain phosphorylation. There is abundant evidence that the ROCK pathwa...Rho kinase （ROCK） was the first downstream Rho effector found to mediate RhoA-induced actin cytoskeletal changes through effects on myosin light chain phosphorylation. There is abundant evidence that the ROCK pathway participates in the pathogenesis of retinal endothelial injury and proliferative epiretinal membrane traction. In this study, we investigated the effect of the ROCK pathway inhibitor Y-27632 on retinal Müller cells subjected to hypoxia or oxidative stress. Müller cells were subjected to hypoxia or oxidative stress by exposure to CoCl2 or H2O2. After a 24-hour treatment with Y-27632, the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide assay was used to assess the survival of Müller cells. Hoechst 33258 was used to detect apoptosis, while 2′,7′-dichlorodihydrofluorescein diacetate was used to measure reactive oxygen species generation. A transwell chamber system was used to examine the migration ability of Müller cells. Western blot assay was used to detect the expression levels of α-smooth muscle actin, glutamine synthetase and vimentin. After treatment with Y-27632, Müller cells subjected to hypoxia or oxidative stress exhibited a morphology similar to control cells. Y-27632 reduced apoptosis, α-smooth muscle actin expression and reactive oxygen species generation under oxidative stress, and it reduced cell migration under hypoxia. Y-27632 also upregulated glutamine synthetase expression under hypoxia but did not impact vimentin expression. These findings suggest that Y-27632 protects Müller cells against cellular injury caused by oxidative stress and hypoxia by inhibiting the ROCK pathway.展开更多
The degradation of Microcystin-LR (MC-LR) in water by hydrogen peroxide assisted ultraviolet (UV/H2O2) process was investigated in this paper. The UV/H2O2 process appeared to be effective in removal of the MC-LR. MC-L...The degradation of Microcystin-LR (MC-LR) in water by hydrogen peroxide assisted ultraviolet (UV/H2O2) process was investigated in this paper. The UV/H2O2 process appeared to be effective in removal of the MC-LR. MC-LR decomposition was primarily ascribed to production of strong and nonselective oxidant-hydroxyl radicals within the system. The intensity of UV radiation, initial concentration of MC-LR, MC-LR purity, dosages of H2O2, the initial solution pH, and anions present in water, to some extent, influenced the degradation rate of MC-LR. A modified pseudo-first-order kinetic model was developed to predict the removal efficiency under different experimental conditions.展开更多
Three-dimensionally ordered mesoporous Fe2O3（meso-Fe2O3） and its supported Au, Pd,and Au-Pd alloy（xA uP dy/meso-Fe2O3; x = 0.08–0.72 wt.%; Pd/Au molar ratio（y） = 1.48–1.85）photocatalysts have been prepared via...Three-dimensionally ordered mesoporous Fe2O3（meso-Fe2O3） and its supported Au, Pd,and Au-Pd alloy（xA uP dy/meso-Fe2O3; x = 0.08–0.72 wt.%; Pd/Au molar ratio（y） = 1.48–1.85）photocatalysts have been prepared via the KIT-6-templating and polyvinyl alcohol-protected reduction routes, respectively. Physical properties of the samples were characterized, and their photocatalytic activities were evaluated for the photocatalytic oxidation of acetone in the presence of a small amount of H2O2 under visible-light illumination. It was found that the meso-Fe2O3 was rhombohedral in crystal structure. The as-obtained samples displayed a high surface area of 111.0–140.8 m^2/g and a bandgap energy of 1.98–2.12 eV. The Au, Pd and/or Au–Pd alloy nanoparticles（NPs） with a size of 3–4 nm were uniformly dispersed on the surface of the meso-Fe2O3 support. The 0.72 wt.% AuP d1.48/meso-Fe2O3 sample performed the best in the presence of 0.06 mol/L H2O2 aqueous solution, showing a 100% acetone conversion within4 hr of visible-light illumination. It was concluded that the good performance of 0.72 wt.%AuPd（1.48）/meso-Fe2O3 for photocatalytic acetone oxidation was associated with its ordered mesoporous structure, high adsorbed oxygen species concentration, plasmonic resonance effect between AuPd（1.48） NPs and meso-Fe2O3, and effective separation of the photogenerated charge carriers. In addition, the introduction of H2O2 and the involvement of the photo-Fenton process also played important roles in enhancing the photocatalytic activity of 0.72 wt.%AuPd（1.48）/meso-Fe2O3.展开更多
A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observe...A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.展开更多
The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the disinfection of water polluted by microcystins. The influenc...The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the disinfection of water polluted by microcystins. The influence factors such as H2O2, pH and UV light intensities were investigated respectively. Degradation of microcystin-RR （MC-RR） could be fitted by either the pseudo-first-order or second-order rate equations. This homogenous system could significantly enhance the degradation rate due to the synergetic effect between UV and H2O2. The degradation mainly followed the mechanism of direct photolysis and .OH oxidation reactions. Experimental results showed that 94.83% of MC-RR was removed under optimal experimental conditions and the UV/H2O2 system provided an alternative to promote the removal of microcystins in drinking water supplies.展开更多
Two azo dyes,C.I.Reactive Red 195(RR195)and C.I.Acid Black 234(AB234)were degraded by photocatalysis of Fe(Ⅲ)-oxalate complexes/H2O2 in aqueous non-ionic surfactant,Triton X-100(TX-100)solution.Some factors affecting...Two azo dyes,C.I.Reactive Red 195(RR195)and C.I.Acid Black 234(AB234)were degraded by photocatalysis of Fe(Ⅲ)-oxalate complexes/H2O2 in aqueous non-ionic surfactant,Triton X-100(TX-100)solution.Some factors affecting the dye degradation such as TX-100 concentration,irradiation intensity,and sodium chloride were investigated.The interaction and competition between dye and TX-100 during the degradation were also examined using spectrophotometry and maximum bubble pressure method,respectively.The results indicated that TX-100 showed a significant reduction effect on degradation of two azo dyes,but which was largely confined to TX-100 concentration below the Critical Micellar Concentration(CMC).And the reduction was considerably decreased above the CMC,especially in the case of AB234.Moreover,the reducing effect of TX-100 on dye degradation almost did not vary with irradiation intensity.And the impact of sodium chloride on dye degradation was limited by the addition of TX-100.展开更多
In order to obtain the chitosan oligomers, chitosan was irradiated in the solid state with and without H 2 O 2 as a radiation degradation sensitizer, respectively. At room temperature, the viscosity average-molecular ...In order to obtain the chitosan oligomers, chitosan was irradiated in the solid state with and without H 2 O 2 as a radiation degradation sensitizer, respectively. At room temperature, the viscosity average-molecular weight (M η ) of chitosan was decreased from 1.6 × 106 to 2.2 × 105 at an absorbed dose of 72 kGy without H2O2, and decreased to 2.7 × 104 at 2 kGy in the presence of an appropriate H2O2 content. In addition, the radiation degradation rate of chitosan containing 38.2wt% H2O2 is 59 times higher than that in the solid state without H2O2. FT-IR analysis suggests that there is no obvious change in the chemical structure of irradiated chitosan with and without H2O2 at a dose below 20 kGy, compared with unirradiated chitosan. On the other hand, the degree of deacetylation (DD) of irradiated chitosan in the studied dose range changed slightly, while DD of irradiated chitosan with H2O2 increased significantly. The XRD pattern indicates that the irradiated chitosan with H2O2 has more perfect crystalline structure than unirradiated chitosan. Therefore, it could be expected that irradiation of chitosan using H2O2 as a sensitizer would be a very effective method to prepare low molecular weight chitosan, because of its feasibility and benignancy to environment.展开更多
Large amounts of cyanide tailings are produced during the cyanidation process in gold extraction,which are hazardous solid wastes due to the toxic cyanide.Pyrite is one of the main minerals in cyanide tailings.The rem...Large amounts of cyanide tailings are produced during the cyanidation process in gold extraction,which are hazardous solid wastes due to the toxic cyanide.Pyrite is one of the main minerals in cyanide tailings.The removal of cyanide adsorbed on pyrite by H_2O_2 oxidation under alkaline conditions was investigated in this study.It was found that the removal efficiency was positively correlated with pH from 5 to 12,but remained almost constant when pH was higher than 12.The highest cyanide removal efficiency of 91.10% was achieved by adding no less than 0.6 wt.% of H_2O_2.Cyanide removal was positively correlated with the CN^-adsorption amount between 1.06 and 8.5 mg/g,and temperature between 25 and 85°C.The removal of cyanide adsorbed on pyrite by H_2O_2 oxidation under alkaline conditions was due to the oxidation of pyrite.Hexacyanoferrate,thiocyanate and sulfate were generated with mole ratios of about 2.03:1.12:3.17 during the cyanide removal.?2018 The Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences.展开更多
Mn-Ni oxides with different compositions were prepared using standard co-precipitation(CP) and urea hydrolysis-precipitation(UH) methods and optimized for the selective catalytic reduction of nitrogen oxides(NOx) by N...Mn-Ni oxides with different compositions were prepared using standard co-precipitation(CP) and urea hydrolysis-precipitation(UH) methods and optimized for the selective catalytic reduction of nitrogen oxides(NOx) by NH3 at low temperature.Mn((2))Ni(1)Ox-CP and Mn(2)Ni(1)Ox-UH(with Mn:Ni molar ratio of 2:1) catalysts showed almost identical selective catalytic reduction(SCR) catalytic activity,with about 96% NOx conversion at 750 C and-99%in the temperature range from 100 to 250℃.X-ray diffraction(XRD) results showed that Mn(2)Ni(1)Ox-CP and Mn(2)Ni(1)Ox-UH catalysts crystallized in the form of Mn2NiO4 and MnO2-Mn2NiO4 spinel,respectively.The latter gave relatively good selectivity to N2,which might be due to the presence of the MnO2 phase and high metal-O binding energy,resulting in low dehydrogenation ability.According to the results of various characterization methods,it was found that a high density of surface chemisorbed oxygen species and efficient electron transfer between Mn and Ni in the crystal structure of Mn2NiO4 spinel played important roles in the high-efficiency SCR activity of these catalysts.Mn(2)Ni(1)Ox catalysts presented good resistance to H2O or/and SO2 with stable activity,which benefited from the Mn2NiO4 spinel structure and Eley-Rideal mechanism,with only slight effects from SO2.展开更多
基金financially supported by the Education Department of Liaoning Province(No.2009A421)
文摘A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol （2-CP） and 4-chlorophenol （4-CP） were prepared, and the supported CuO catalysts were studied particularly. The supported CuO catalysts were characterized by XRD and NH3-TPD techniques, in which CuO/γ-Al2O3 exhibited high degradation activity. The addition of Na2O or K2O into CuO/γ-Al2O3 improved the oxidative degradation of CPs remarkably, in which Na2O was more efficient than K2O. Over CuO/γ-Al2O3-Na2O, CPs were completely converted and the liberation of the inorganic chloride from 2-CP or 4-CP reached 97% or 100% respectively at 30 ？C for 2 h. The supported CuO catalysts with good dispersion of CuO particles and less acid sites were favorable for the efficient oxidative degradation of CPs. In addition, the initial pH of the reaction solution was found to be an important factor which influenced the catalytic oxidative degradation of CPs and the initial pH of 11.2 and 9.8 was preferred for the oxidative degradation of 2-CP and 4-CP respectively over CuO/γ-Al2O3 catalyst.
基金supported by the National Natural Science Foundation of China(Nos.51678270,21872063)111 Project of Jilin University,China(No.B16020)。
文摘The extensive use of tetracycline hydrochloride(TCH)poses a threat to human health and the aquatic environment.Here,magnetic p-n Bi2WO6/CuFe2O4 catalyst was fabricated to efficiently remove TCH.The obtained Bi2WO6/CuFe2O4 exhibited 92.1%TCH degradation efficiency and 50.7%and 35.1%mineralization performance for TCH and raw secondary effluent from a wastewater treatment plant in a photo-Fenton-like system,respectively.The remarkable performance was attributed to the fact that photogenerated electrons accelerated the Fe(III)/Fe(II)and Cu(II)/Cu(I)conversion for the Fenton-like reaction between Fe(II)/Cu(I)and H2O2,thereby generating abundant·OH for pollutant oxidation.Various environmental factors including H2O2 concentration,initial pH,catalyst dosage,TCH concentration and inorganic ions were explored.The reactive oxidation species(ROS)quenching results and electron spin resonance(ESR)spectra confirmed that·O2-and·OH were responsible for the dark and photo-Fenton-like systems,respectively.The degradation mechanisms and pathways of TCH were proposed,and the toxicity of products was evaluated.This work contributes a highly efficient and environmentally friendly catalyst and provides a clear mechanistic explanation for the removal of antibiotic pollutants in environmental remediation.
文摘The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H 2O 2/UV has beneficial effect on mineralization than O 3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.
基金supported by the National Natural Science Foundation of China(21273086)Chutian Scholar Foundation from Hubei Province,China~~
文摘The development of new catalytic techniques for wastewater treatment has long attracted much attention from industrial and academic communities.However,because of catalyst leaching during degradation,catalysts can be short lived,and therefore expensive,and unsuitable for use in wastewater treatment.In this work,we developed a bimetallic CuO-Co3O4@γ-Al2O3 catalyst for phenol degradation with bicarbonate-activated H2O2.The weakly basic environment provided by the bicarbonate buffer greatly suppresses leaching of active Cu and Co metal ions from the catalyst.X-ray diffraction and X-ray photoelectron spectroscopy results showed interactions between Cu and Co ions in the CuO-Co3O4@γ-Al2O3 catalyst,and these improve the catalytic activity in phenol degradation.Mechanistic studies using different radical scavengers showed that superoxide and hydroxyl radicals both played significant roles in phenol degradation,whereas singlet oxygen was less important.
基金supported by the National Natural Science Foundation of China (Grant No.50772006)
文摘Highly ordered Cu2O coated silicon nanowire arrays （SiNWAs） were fabricated as photocatalyst via depositing Cu nanoparticles on silver-assisted electroless-etched SiNWAs and subsequently annealing. The as-prepared samples have been characterized by scanning electron microscopy, X-ray diffraction and UV-VIS-NIR spectrophotometry. The photocatalytic properties of the Cu2O coated SiNWAs were investigated by degradation of Rhodamine B （RhB） under simulated solar light with a cut-off filter （λ 〉 420 nm）. The results indicated that H2O2 could greatly improve the photocatalytic properties of Cu2O coated SiNWAs, and exhibited strong synergy effect between them. The hybrid nanowire arrays will be promising photocatalytic materials in the field of energy and environment.
基金supported by the National Natural Science Foundation of China(No.51908536)the Ministry of Science and Technology of China(No.2018YFE0204103)。
文摘The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.
基金This project was supported by the National Natural Science Foundation of Zhejiang Province(No.Y407306)the National Natural Science Foundation of China(No.20876148)
文摘An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals.Various substituted toluenes（NO2,Cl,Br,H,CH3） were high selectively brominated at the benzyl position for monobromination in CH2C12 at ice water with catalyst free.This simple but effective bromination of toluene derivatives with an aqueous H2O2-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.
基金Supported by the National Natural Science Foundation of China(51009115)Shaanxi Provincial Department of Education Key Laboratory Project(13JS067)+2 种基金the Hall of Shaanxi Province Science and Technology(2013JK0881)the Research Plan Project of Water Resources Department of Shaanxi Province(2013slkj-07)the Innovation of Science and Technology Fund of Xi'an University of Technology(211302)
文摘Fe3O4 magnetic nanoparticles(MNPs) were synthesised, characterised, and used as a peroxidase mimetic to accelerate levofloxacin sono-degradation in an ultrasound(US)/H2O2 system. The Fe3O4 MNPs were in nanometre scale with an average diameter of approximately 12 to 18 nm. The introduction of Fe3O4 MNPs increased levofloxacin sono-degradation in the US/H2O2 system. Experimental parameters, such as Fe3O4 MNP dose, initial solution p H, and H2O2 concentration, were investigated by a one-factor-at-a-time approach. The results showed that Fe3O4 MNPs enhanced levofloxacin removal in the p H range from 4.0 to 9.0. Levofloxacin removal ratio increased with Fe3O4 MNP dose up to 1.0 g·L-1and with H2O2 concentration until reaching the maximum. Moreover, three main intermediate compounds were identified by HPLC with electrospray ionisation tandem mass spectrometry, and a possible degradation pathway was proposed. This study suggests that combination of H2O2, Fe3O4 MNPs and US is a good way to improve the degradation efficiency of antibiotics.
基金financially supported by the Scientific and Technological Project of Shaanxi Province of China,No.2016SF-010
文摘Rho kinase （ROCK） was the first downstream Rho effector found to mediate RhoA-induced actin cytoskeletal changes through effects on myosin light chain phosphorylation. There is abundant evidence that the ROCK pathway participates in the pathogenesis of retinal endothelial injury and proliferative epiretinal membrane traction. In this study, we investigated the effect of the ROCK pathway inhibitor Y-27632 on retinal Müller cells subjected to hypoxia or oxidative stress. Müller cells were subjected to hypoxia or oxidative stress by exposure to CoCl2 or H2O2. After a 24-hour treatment with Y-27632, the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide assay was used to assess the survival of Müller cells. Hoechst 33258 was used to detect apoptosis, while 2′,7′-dichlorodihydrofluorescein diacetate was used to measure reactive oxygen species generation. A transwell chamber system was used to examine the migration ability of Müller cells. Western blot assay was used to detect the expression levels of α-smooth muscle actin, glutamine synthetase and vimentin. After treatment with Y-27632, Müller cells subjected to hypoxia or oxidative stress exhibited a morphology similar to control cells. Y-27632 reduced apoptosis, α-smooth muscle actin expression and reactive oxygen species generation under oxidative stress, and it reduced cell migration under hypoxia. Y-27632 also upregulated glutamine synthetase expression under hypoxia but did not impact vimentin expression. These findings suggest that Y-27632 protects Müller cells against cellular injury caused by oxidative stress and hypoxia by inhibiting the ROCK pathway.
基金supported by the National Key Technologies Supporting Program of China during the 11th Five-Year Plan Period (No. 2006BAJ08B06)the National Major Project of Science & Technology Ministry of China (No. 2008ZX07421-002)the Shanghai Science & Technology Commission Key Scientific & Technological Project (No. 072312001), China
文摘The degradation of Microcystin-LR (MC-LR) in water by hydrogen peroxide assisted ultraviolet (UV/H2O2) process was investigated in this paper. The UV/H2O2 process appeared to be effective in removal of the MC-LR. MC-LR decomposition was primarily ascribed to production of strong and nonselective oxidant-hydroxyl radicals within the system. The intensity of UV radiation, initial concentration of MC-LR, MC-LR purity, dosages of H2O2, the initial solution pH, and anions present in water, to some extent, influenced the degradation rate of MC-LR. A modified pseudo-first-order kinetic model was developed to predict the removal efficiency under different experimental conditions.
基金supported by the National Natural Science Foundation of China (No. 21377008)the National High Technology Research and Development Program of China ("863"Program)(No. 2015AA034603)the Foundation of the Creative Research Team Construction Promotion Project of Beijing Municipal Institutions
文摘Three-dimensionally ordered mesoporous Fe2O3（meso-Fe2O3） and its supported Au, Pd,and Au-Pd alloy（xA uP dy/meso-Fe2O3; x = 0.08–0.72 wt.%; Pd/Au molar ratio（y） = 1.48–1.85）photocatalysts have been prepared via the KIT-6-templating and polyvinyl alcohol-protected reduction routes, respectively. Physical properties of the samples were characterized, and their photocatalytic activities were evaluated for the photocatalytic oxidation of acetone in the presence of a small amount of H2O2 under visible-light illumination. It was found that the meso-Fe2O3 was rhombohedral in crystal structure. The as-obtained samples displayed a high surface area of 111.0–140.8 m^2/g and a bandgap energy of 1.98–2.12 eV. The Au, Pd and/or Au–Pd alloy nanoparticles（NPs） with a size of 3–4 nm were uniformly dispersed on the surface of the meso-Fe2O3 support. The 0.72 wt.% AuP d1.48/meso-Fe2O3 sample performed the best in the presence of 0.06 mol/L H2O2 aqueous solution, showing a 100% acetone conversion within4 hr of visible-light illumination. It was concluded that the good performance of 0.72 wt.%AuPd（1.48）/meso-Fe2O3 for photocatalytic acetone oxidation was associated with its ordered mesoporous structure, high adsorbed oxygen species concentration, plasmonic resonance effect between AuPd（1.48） NPs and meso-Fe2O3, and effective separation of the photogenerated charge carriers. In addition, the introduction of H2O2 and the involvement of the photo-Fenton process also played important roles in enhancing the photocatalytic activity of 0.72 wt.%AuPd（1.48）/meso-Fe2O3.
基金Funded by the National Natural Science Foundation of China(No.21476177)。
文摘A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.
文摘The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the disinfection of water polluted by microcystins. The influence factors such as H2O2, pH and UV light intensities were investigated respectively. Degradation of microcystin-RR （MC-RR） could be fitted by either the pseudo-first-order or second-order rate equations. This homogenous system could significantly enhance the degradation rate due to the synergetic effect between UV and H2O2. The degradation mainly followed the mechanism of direct photolysis and .OH oxidation reactions. Experimental results showed that 94.83% of MC-RR was removed under optimal experimental conditions and the UV/H2O2 system provided an alternative to promote the removal of microcystins in drinking water supplies.
基金National Natural Science Foundation of China(No.20773093)Tianjin Municipal Science Programme Foundation,China(No.043605911)
文摘Two azo dyes,C.I.Reactive Red 195(RR195)and C.I.Acid Black 234(AB234)were degraded by photocatalysis of Fe(Ⅲ)-oxalate complexes/H2O2 in aqueous non-ionic surfactant,Triton X-100(TX-100)solution.Some factors affecting the dye degradation such as TX-100 concentration,irradiation intensity,and sodium chloride were investigated.The interaction and competition between dye and TX-100 during the degradation were also examined using spectrophotometry and maximum bubble pressure method,respectively.The results indicated that TX-100 showed a significant reduction effect on degradation of two azo dyes,but which was largely confined to TX-100 concentration below the Critical Micellar Concentration(CMC).And the reduction was considerably decreased above the CMC,especially in the case of AB234.Moreover,the reducing effect of TX-100 on dye degradation almost did not vary with irradiation intensity.And the impact of sodium chloride on dye degradation was limited by the addition of TX-100.
文摘In order to obtain the chitosan oligomers, chitosan was irradiated in the solid state with and without H 2 O 2 as a radiation degradation sensitizer, respectively. At room temperature, the viscosity average-molecular weight (M η ) of chitosan was decreased from 1.6 × 106 to 2.2 × 105 at an absorbed dose of 72 kGy without H2O2, and decreased to 2.7 × 104 at 2 kGy in the presence of an appropriate H2O2 content. In addition, the radiation degradation rate of chitosan containing 38.2wt% H2O2 is 59 times higher than that in the solid state without H2O2. FT-IR analysis suggests that there is no obvious change in the chemical structure of irradiated chitosan with and without H2O2 at a dose below 20 kGy, compared with unirradiated chitosan. On the other hand, the degree of deacetylation (DD) of irradiated chitosan in the studied dose range changed slightly, while DD of irradiated chitosan with H2O2 increased significantly. The XRD pattern indicates that the irradiated chitosan with H2O2 has more perfect crystalline structure than unirradiated chitosan. Therefore, it could be expected that irradiation of chitosan using H2O2 as a sensitizer would be a very effective method to prepare low molecular weight chitosan, because of its feasibility and benignancy to environment.
基金supported by the National Key Research and Development Program of China (No. 2017YFC0703200)
文摘Large amounts of cyanide tailings are produced during the cyanidation process in gold extraction,which are hazardous solid wastes due to the toxic cyanide.Pyrite is one of the main minerals in cyanide tailings.The removal of cyanide adsorbed on pyrite by H_2O_2 oxidation under alkaline conditions was investigated in this study.It was found that the removal efficiency was positively correlated with pH from 5 to 12,but remained almost constant when pH was higher than 12.The highest cyanide removal efficiency of 91.10% was achieved by adding no less than 0.6 wt.% of H_2O_2.Cyanide removal was positively correlated with the CN^-adsorption amount between 1.06 and 8.5 mg/g,and temperature between 25 and 85°C.The removal of cyanide adsorbed on pyrite by H_2O_2 oxidation under alkaline conditions was due to the oxidation of pyrite.Hexacyanoferrate,thiocyanate and sulfate were generated with mole ratios of about 2.03:1.12:3.17 during the cyanide removal.?2018 The Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences.
基金financially supported by the National Key R&D Program of China (No.2017YFC0210303)National Natural Science Foundation of China (Nos.21806009 and 21677010)+1 种基金China Postdoctoral Science Foundation (Nos.2019T120049 and 2018M631344)Fundamental Research Funds for the Central Universities (No.FRF-TP-18-019A1).
文摘Mn-Ni oxides with different compositions were prepared using standard co-precipitation(CP) and urea hydrolysis-precipitation(UH) methods and optimized for the selective catalytic reduction of nitrogen oxides(NOx) by NH3 at low temperature.Mn((2))Ni(1)Ox-CP and Mn(2)Ni(1)Ox-UH(with Mn:Ni molar ratio of 2:1) catalysts showed almost identical selective catalytic reduction(SCR) catalytic activity,with about 96% NOx conversion at 750 C and-99%in the temperature range from 100 to 250℃.X-ray diffraction(XRD) results showed that Mn(2)Ni(1)Ox-CP and Mn(2)Ni(1)Ox-UH catalysts crystallized in the form of Mn2NiO4 and MnO2-Mn2NiO4 spinel,respectively.The latter gave relatively good selectivity to N2,which might be due to the presence of the MnO2 phase and high metal-O binding energy,resulting in low dehydrogenation ability.According to the results of various characterization methods,it was found that a high density of surface chemisorbed oxygen species and efficient electron transfer between Mn and Ni in the crystal structure of Mn2NiO4 spinel played important roles in the high-efficiency SCR activity of these catalysts.Mn(2)Ni(1)Ox catalysts presented good resistance to H2O or/and SO2 with stable activity,which benefited from the Mn2NiO4 spinel structure and Eley-Rideal mechanism,with only slight effects from SO2.
