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
A graphite carbon nitride(g-C3N4)modified Bi4O5I2 composite was successfully prepared insitu via the thermal treatment of a g-C3N4/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C3N4/Bi4O5I2 showed high phot...A graphite carbon nitride(g-C3N4)modified Bi4O5I2 composite was successfully prepared insitu via the thermal treatment of a g-C3N4/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C3N4/Bi4O5I2 showed high photocatalytic performance in Methyl Orange(MO)degradation under visible light.The best sample presented a degradation rate of 0.164 min^-1,which is 3.2 and 82 times as high as that of Bi4O5I2 and g-C3N4,respectively.The g-C3N4/Bi4O5I2 was characterized by X-ray powder diffractometer(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman,X-ray photoelectron spectroscopy(XPS),ultraviolet-visible diffuse reflectance spectra(DRS),electrochemical impedance spectroscopy(EIS)and transient photocurrent response in order to explain the enhanced photoactivity.Results indicated that the decoration with a small amount of g-C3N4 influenced the specific surface area only slightly.Nevertheless,the capability for absorbing visible light was improved measurably,which was beneficial to the MO degradation.On top of that,a strong interaction between g-C3N4 and Bi4O5I2 was detected.This interplay promoted the formation of a favorable heterojunction structure and thereby enhanced the charge separation.Thus,the g-C3N4/Bi4O5I2 composite presented greater charge separation efficiency and much better photocatalytic performance than Bi4O5I2.Additionally,g-C3N4/Bi4O5I2 also presented high stability.·O2^- and holes were verified to be the main reactive species.展开更多
Perfluorooctanoic acid （PFOA） is a new-found hazardous persistent organic pollutant, and it is resistant to decomposition by hydroxyl radical （HO.） due to its stable chemical structure and the high electronegativi...Perfluorooctanoic acid （PFOA） is a new-found hazardous persistent organic pollutant, and it is resistant to decomposition by hydroxyl radical （HO.） due to its stable chemical structure and the high electronegativity of fluorine. Photocatalytic reduction of PFOA with β-Ga2O3 in anoxic aqueous solution was investigated for the first time, and the results showed that the photoinduced electron （ecb） coming from the β-Ga2O3 conduction band was the major degradation substance for PFOA, and shorter-chain perfluorinated carboxylic acids （PFCAs, CnF2n＋1COOH, 1 ≤ n ≤ 6） were the dominant products. Furthermore, the concentration of F- was measured by the IC technique and defluorination efficiency was calculated. After 3 hr, the photocatalytic degradation efficiency was 98.8% and defluorination efficiency was 31.6% in the presence of thiosulfate and bubbling N2. The degradation reaction followed first-order kinetics （k = 0.0239 min-1, t1/2 = 0.48 hr）. PFCAs （CnF2n＋xCOOH, 1 ≤ n≤ 7） were detected and measured by LC-MS and LC-MS/MS methods. It was deduced that the probable photocatalytic degradation mechanism involves ec-b attacking the carboxyl of CnF2n＋1COOH, resulting in decarboxylation and the generation of CnFzn＋1. The produced CnF2n＋1 reacted with H2O, forming CnF2n＋1OH, then CnF2n＋1OH underwent HF loss and hydrolysis to form CnF2,＋1COOH.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
研究了O_3-H_2O_2体系降解膜滤垃圾浓缩液中有机物的效果与特点。结果表明,在反应时间为30 min,臭氧投加质量流量为4 g/h时,添加4 m L/L的H2O2可取得理想的处理效果,BOD_5/COD由0.025提升至0.527,对色度、腐殖酸、COD的去除率分别为86....研究了O_3-H_2O_2体系降解膜滤垃圾浓缩液中有机物的效果与特点。结果表明,在反应时间为30 min,臭氧投加质量流量为4 g/h时,添加4 m L/L的H2O2可取得理想的处理效果,BOD_5/COD由0.025提升至0.527,对色度、腐殖酸、COD的去除率分别为86.99%、62.94%、53.03%,较之O_3体系的去除率分别提高了23.05%、18.91%、19.55%,原因是适量的H_2O_2有强化反应体系中自由基的作用。O_3-H_2O_2体系能将腐殖酸等大分子有机物分解为小分子烷烃类等臭氧惰性产物,随反应时间的延长以及H2O2的影响,p H有下降的趋势,且有机物的降解逐渐矿化为CO_3^(2-),由此导致了反应后期臭氧的利用率下降以及有机物的去除速率有所降低。展开更多
Given the difficulties of degrading benzotriazole(BTA),this study used a one-pot hydrothermal method to prepareα-Fe_(2)O_(3)/Cu_(2)O(FC)composites for photoelectrocatalytic(PEC)degradation of BTA.The characterization...Given the difficulties of degrading benzotriazole(BTA),this study used a one-pot hydrothermal method to prepareα-Fe_(2)O_(3)/Cu_(2)O(FC)composites for photoelectrocatalytic(PEC)degradation of BTA.The characterization of FC structure showed that Cu_(2)O in cubic crystals was loaded with circular sheets of Fe_(2)O_(3).Owing to this structure,FC showed efficient PEC degradation of BTA when exposed to ultraviolet light.The experimental results demonstrated that FC efficiently degraded BTA.When the PEC degradation continued for 60 min,100%degradation of BTA was achieved because FC enhanced the photoelectron-hole separation and the separation and transfer of articulated carriers.High per-formance liquid chromatography-mass spectrometry showed that intermediates formed during the PEC degradation of BTA.Finally,various pathways for degradation of BTA were postulated.This FC-based PEC system provides a harmless and effective method for degradation of BTA.展开更多
Positive bias temperature instability stress induced interface trap density in a buried InGaAs channel metaloxide-semiconductor field-effect transistor with a InCaP barrier layer and Al2O3 dielectric is investigated. ...Positive bias temperature instability stress induced interface trap density in a buried InGaAs channel metaloxide-semiconductor field-effect transistor with a InCaP barrier layer and Al2O3 dielectric is investigated. Well behaved split C-V characteristics with small capacitance frequency dispersion are confirmed after the insertion of the InCaP barrier layer. The direct-current Id-Vg measurements show both degradations of positive gate voltage shift and sub-threshold swing in the sub-threshold region, and degradation of positive △Vg in the oncurrent region. The Id-Vg degradation during the positive bias temperature instability tests is mainly contributed by the generation of near interface acceptor traps under stress. Specifically, the stress induced aeceptor traps contain both permanent and recoverable traps. Compared with surface channel InCaAs devices, stress induced recoverable donor traps are negligible in the buried channel ones.展开更多
A novel and effective BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst was synthesized through a precipitation method. The structure, morphology, and optical properties of the samples were certified by X-ray diffraction, UV...A novel and effective BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst was synthesized through a precipitation method. The structure, morphology, and optical properties of the samples were certified by X-ray diffraction, UV-Vis diffuse reflectance, scanning electron microscopy, and X-ray photoelectron spectroscopic characterizations. Photocatalytic experiments demonstrated that the synthesized BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst exhibited excellent photocatalytic performance toward the degradation of tetracycline hydrochloride(TCH) under simulated sunlight. Furthermore, the TCH degradation rate of BiOCl0.9I0.1/15%β-Bi2O3 increased by 27.6% and 61.4% compared with those of the pure BiOCl0.9I0.1 and pure β-Bi2O3, respectively. Due to the multiple vacancies and valence states possessed by BiOCl0.9I0.1/x%β-Bi2O3, namely Bi5+, Bi(3-x)+, Bi5+–O, Bi3+–O, I- and I3-, the charge separation in photocatalysis reactions can be effectively promoted. The Mott-Schottky measurements indicate that the conduction band(CB) level of BiOCl0.9I0.1/15%β-Bi2O3 becomes more negative relative to that of BiOCl0.9I0.1, guaranteeing an advantageous effect on the redox ability of the photocatalyst. This study provides a new bright spot for the construction of high-performance photocatalysts.展开更多
The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount...The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g,, it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84--24 mg/m^3 by O3/TiO2flJV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m^3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/（m^3.min） and Langmuir adsorption coefficient K of 0.0268 m^3/mg were obtained.展开更多
In order to develop a catalyst with high activity for catalytic wet oxidation （CWO） process at room temperature and atmospheric pressure, Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst was prepared by consecutive impregnation me...In order to develop a catalyst with high activity for catalytic wet oxidation （CWO） process at room temperature and atmospheric pressure, Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst was prepared by consecutive impregnation method and the prepared parameters were optimized. The structure of the catalyst was characterized by BET, XRF, SEM and XPS technologies, and the actual wastewater was used to investigate the catalytic activity of Fe2O3-CeO2-TiO2/γ-Al2O3 in CWO process. The experimental results showed that the prepared catalyst exhibited good catalytic activity when the doping amount of Ti was 1.0 wt% （the weight ratio of Ti to carriers）, and the middle product, Fe2O3-CeO2-TiO2/γ-Al2O3, was calcined in 450℃ for 2 h. The CWO experiment for treating actual dye wastewater indicated that the COD, color and TOC of actual wastewater were decreased by 62.23%, 50.12% and 41.26% in 3 h, respectively, and the ratio of BOD5/COD was increased from 0.19 to 0.30.展开更多
The combination of leachate recirculation and aeration to landfill may be an efficient way for in-situ nitrogen removal.However,nitrogenous substances contained in the landfill layer are concomitantly transformed into...The combination of leachate recirculation and aeration to landfill may be an efficient way for in-situ nitrogen removal.However,nitrogenous substances contained in the landfill layer are concomitantly transformed into N2O and NH3,leading to increased emissions into the atmosphere.In the present study,the emissions of N2O and NH3 were measured under conditions of fresh or partially stabilized refuse with or without leachate recirculation or intermittent aeration.The results showed that the largest N2O emission（12.4 mg-N/L of the column） was observed in the aerated column loaded with partially stabilized refuse and recycled with the leachate of low C/N ratio;while less than 0.33 mg-N/L of the column was produced in the other columns.N2O production was positively correlated with the prolonged aerobic time and negatively related with the C/N ratio in the recycled leachate.NH3 volatilization increased with enhanced gas flow and concentration of free ammonia in the leachate,and the highest cumulative volatilization quantity was 1.7 mg-N/L of the column.展开更多
ZnO/Znml2O4 nanocomposites with heteronanostructures were successfully prepared by co-precipitation method. The as-prepared samples were characterized by HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. Th...ZnO/Znml2O4 nanocomposites with heteronanostructures were successfully prepared by co-precipitation method. The as-prepared samples were characterized by HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photoeatalytic activities of the as-prepared samples were evaluated by the photocatalytic degradation of methyl orange and inactivation of Escherichia coli in suspension under the irradiation of the simulated sunlight. The effects of compositions, calcination temperatures, concentration ofphotocatalysts and light source on the photocatalytic activities were systematically studied. The results show that when the concentration of ZnO/ZnA1204 photocatalyst with the starting Zn to Al molar ratio of 1：1.5 calcined at 600 ℃ is 1.0 g/L, the maximum photocatalytic degradation rate of 98.5% can be obtained in 50 min under the irradiation of the simulated sunlight. Under the same conditions, an inactivation rate of 99.8% for E.coli is achieved in 60 min.展开更多
A nanoheterojunction composite photocatalyst Bi2O3/TiO2 working under visible-light （λ≥ 420 nm） was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2 molar ratio. Maleic acid was emplo...A nanoheterojunction composite photocatalyst Bi2O3/TiO2 working under visible-light （λ≥ 420 nm） was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2 molar ratio. Maleic acid was employed as an organic binder to unite Bi2O3 and TiO2 nanoparticles. The SEM, TEM, XRD and diffuse reflectance spectra were utilized to characterize the prepared Bi2O3/TiO2 nanoheterojunction. The nanocomposite exhibited unusual high photocatalytic activity in decomposing 2-propanol in gas phase and phenol in aqueous phase and, evolution of CO2 under visible light irradiation while the end members exhibited low photocatalytic activity. The composite was optimized to 5 mol% Bi2O3/TiO2. The remarkable high photocatalytic efficiency originates from the unique relative energy band position of Bi2O3 and TiO2 as well as the absorption of visible light by Bi2O3.展开更多
Fe（II）/γ-Al2O3 powders synthesized using the dipping method were produced from a mixed aqueous solution containing aluminium oxide （γ-Al2O3） and iron（II）-precursor （FeSO4）, and used for photoFenton degradati...Fe（II）/γ-Al2O3 powders synthesized using the dipping method were produced from a mixed aqueous solution containing aluminium oxide （γ-Al2O3） and iron（II）-precursor （FeSO4）, and used for photoFenton degradation of phthalocyanine dyes （PCs） under ultraviolet （UV） irradiation in an up-flow fluidized bed. The catalysts were characterized by XRD, ESCA, BET, EDS and SEM. The results showed that Fe2＋ ion was compounded on the γ-Al2O3 carder. The effects of different reaction parameters such as catalyst activity, dosage and solution pH on the decolorization of PCs were assessed. Results indicated that maximum decolorization （more than 95%） of PCs occurred with 20 wt% Fe（II）/γ-Al2O3 catalyst （dosage of 60 g/L） using a combination of UV irradiation and heterogeneous Fenton system. The degradation efficiency of PCs increases as pH decreases, exhibiting a maximum efficiency at pH 3.5. The recycled catalyst was capable of repeating three runs without a significant decrease in treatment efficiency, and this demonstrated the stability and reusability of catalyst.展开更多
A coaxial dielectric barrier discharge (DBD) reactor was used for plasma-catalytic degradation of tetracycline hydrochloride over a series of Mn/γ-Al2O3 catalysts prepared by the incipient wetness impregnation method...A coaxial dielectric barrier discharge (DBD) reactor was used for plasma-catalytic degradation of tetracycline hydrochloride over a series of Mn/γ-Al2O3 catalysts prepared by the incipient wetness impregnation method.The combination of plasma and the Mn/γ-Al2O3 catalysts significantly enhanced the degradation efficiency of tetracycline hydrochloride compared to the plasma process alone,with the 10% Mn/γ-Al2O3 catalyst exhibiting the best tetracycline hydrochloride degradation efficiency.A maximum degradation efficiency of 99.3% can be achieved after 5 min oxidation and a discharge power of 1.3 W,with only 69.7% by a single plasma process.The highest energy yield of the plasma-catalytic process is 91.7 g kWh-1.Probable reaction mechanisms of the plasma-catalytic removal of tetracycline hydrochloride were also proposed.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
A magnetic CoFe2O4/Cd S nanocomposite was prepared via one-step hydrothermal decomposition of cadmium diethanoldithiocarbamate complex on the surface of CoFe2O4 nanoparticles at a low temperature of 200 ℃.The nanocom...A magnetic CoFe2O4/Cd S nanocomposite was prepared via one-step hydrothermal decomposition of cadmium diethanoldithiocarbamate complex on the surface of CoFe2O4 nanoparticles at a low temperature of 200 ℃.The nanocomposite was characterised by X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy,energy-dispersive X-ray spectroscopy（EDX）,UV-visible spectroscopy,transmission electron microscopy（TEM）,N2 gas sorption analysis,X-ray photoelectron spectroscopy（XPS）,and vibrating sample magnetometry.The FT-IR,XRD,EDX and XPS results confirmed the formation of the CoFe2O4/Cd S nanocomposite.Based on the TEM analysis,the CoFe2O4/Cd S nanocomposite constituted nearly uniform,sphere-like nanoparticles of ～20 nm in size.The optical absorption spectrum of the CoFe2O4/Cd S nanocomposite displayed a band gap of 2.21 e V,which made it a suitable candidate for application in sono/photocatalytic degradation of organic pollutants.Accordingly,the sonocatalytic activity of the CoFe2O4/Cd S nanocomposite was evaluated towards the H2O2-assisted degradation of methylene blue,rhodamine B,and methyl orange under ultrasonic irradiation.The nanocomposite displayed excellent sonocatalytic activity towards the degradation of all dyes examined—the dyes were completely decomposed within 5–9 min.Furthermore,a comparison study revealed that the CoFe2O4/Cd S nanocomposite is a more efficient sonocatalyst than pure Cd S;thus,adopting the nanocomposite approach is an excellent means to improve the sonoactivity of Cd S.Moreover,the magnetic properties displayed by the CoFe2O4/Cd S nanocomposite allow easy retrieval of the catalyst from the reaction mixture for subsequent uses.展开更多
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 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
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financially supported by National Undergraduate Training Program for Innovation and Entrepreneurship(Nos.201810345012 and 201810345051)
文摘A graphite carbon nitride(g-C3N4)modified Bi4O5I2 composite was successfully prepared insitu via the thermal treatment of a g-C3N4/Bi OI precursor at 400°C for 3 hr.The as-prepared g-C3N4/Bi4O5I2 showed high photocatalytic performance in Methyl Orange(MO)degradation under visible light.The best sample presented a degradation rate of 0.164 min^-1,which is 3.2 and 82 times as high as that of Bi4O5I2 and g-C3N4,respectively.The g-C3N4/Bi4O5I2 was characterized by X-ray powder diffractometer(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman,X-ray photoelectron spectroscopy(XPS),ultraviolet-visible diffuse reflectance spectra(DRS),electrochemical impedance spectroscopy(EIS)and transient photocurrent response in order to explain the enhanced photoactivity.Results indicated that the decoration with a small amount of g-C3N4 influenced the specific surface area only slightly.Nevertheless,the capability for absorbing visible light was improved measurably,which was beneficial to the MO degradation.On top of that,a strong interaction between g-C3N4 and Bi4O5I2 was detected.This interplay promoted the formation of a favorable heterojunction structure and thereby enhanced the charge separation.Thus,the g-C3N4/Bi4O5I2 composite presented greater charge separation efficiency and much better photocatalytic performance than Bi4O5I2.Additionally,g-C3N4/Bi4O5I2 also presented high stability.·O2^- and holes were verified to be the main reactive species.
基金supported by the National Natural Science Foundation of China (No. 20907026)the High Level Talent Research Foundation of Qindao Technological University (No:C-10-210)
文摘Perfluorooctanoic acid （PFOA） is a new-found hazardous persistent organic pollutant, and it is resistant to decomposition by hydroxyl radical （HO.） due to its stable chemical structure and the high electronegativity of fluorine. Photocatalytic reduction of PFOA with β-Ga2O3 in anoxic aqueous solution was investigated for the first time, and the results showed that the photoinduced electron （ecb） coming from the β-Ga2O3 conduction band was the major degradation substance for PFOA, and shorter-chain perfluorinated carboxylic acids （PFCAs, CnF2n＋1COOH, 1 ≤ n ≤ 6） were the dominant products. Furthermore, the concentration of F- was measured by the IC technique and defluorination efficiency was calculated. After 3 hr, the photocatalytic degradation efficiency was 98.8% and defluorination efficiency was 31.6% in the presence of thiosulfate and bubbling N2. The degradation reaction followed first-order kinetics （k = 0.0239 min-1, t1/2 = 0.48 hr）. PFCAs （CnF2n＋xCOOH, 1 ≤ n≤ 7） were detected and measured by LC-MS and LC-MS/MS methods. It was deduced that the probable photocatalytic degradation mechanism involves ec-b attacking the carboxyl of CnF2n＋1COOH, resulting in decarboxylation and the generation of CnFzn＋1. The produced CnF2n＋1 reacted with H2O, forming CnF2n＋1OH, then CnF2n＋1OH underwent HF loss and hydrolysis to form CnF2,＋1COOH.
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supported by the Open Program of the Tianjin Key Laboratory of Green Chemical Engineering Process Engineering,Tiangong University,Tianjin(Grant No.GCEPE20190108)the Inner Mongolia Natural Science Foundation(Grant No.2020MS02015)the Regional Science Foundation Project of the National Natural Science Foundation of China(Grant No.42167029)
文摘Given the difficulties of degrading benzotriazole(BTA),this study used a one-pot hydrothermal method to prepareα-Fe_(2)O_(3)/Cu_(2)O(FC)composites for photoelectrocatalytic(PEC)degradation of BTA.The characterization of FC structure showed that Cu_(2)O in cubic crystals was loaded with circular sheets of Fe_(2)O_(3).Owing to this structure,FC showed efficient PEC degradation of BTA when exposed to ultraviolet light.The experimental results demonstrated that FC efficiently degraded BTA.When the PEC degradation continued for 60 min,100%degradation of BTA was achieved because FC enhanced the photoelectron-hole separation and the separation and transfer of articulated carriers.High per-formance liquid chromatography-mass spectrometry showed that intermediates formed during the PEC degradation of BTA.Finally,various pathways for degradation of BTA were postulated.This FC-based PEC system provides a harmless and effective method for degradation of BTA.
基金Supported by the National Science and Technology Major Project of China under Grant No 2011ZX02708-003the National Natural Science Foundation of China under Grant No 61504165the Opening Project of Key Laboratory of Microelectronics Devices and Integrated Technology of Institute of Microelectronics of Chinese Academy of Sciences
文摘Positive bias temperature instability stress induced interface trap density in a buried InGaAs channel metaloxide-semiconductor field-effect transistor with a InCaP barrier layer and Al2O3 dielectric is investigated. Well behaved split C-V characteristics with small capacitance frequency dispersion are confirmed after the insertion of the InCaP barrier layer. The direct-current Id-Vg measurements show both degradations of positive gate voltage shift and sub-threshold swing in the sub-threshold region, and degradation of positive △Vg in the oncurrent region. The Id-Vg degradation during the positive bias temperature instability tests is mainly contributed by the generation of near interface acceptor traps under stress. Specifically, the stress induced aeceptor traps contain both permanent and recoverable traps. Compared with surface channel InCaAs devices, stress induced recoverable donor traps are negligible in the buried channel ones.
文摘A novel and effective BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst was synthesized through a precipitation method. The structure, morphology, and optical properties of the samples were certified by X-ray diffraction, UV-Vis diffuse reflectance, scanning electron microscopy, and X-ray photoelectron spectroscopic characterizations. Photocatalytic experiments demonstrated that the synthesized BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst exhibited excellent photocatalytic performance toward the degradation of tetracycline hydrochloride(TCH) under simulated sunlight. Furthermore, the TCH degradation rate of BiOCl0.9I0.1/15%β-Bi2O3 increased by 27.6% and 61.4% compared with those of the pure BiOCl0.9I0.1 and pure β-Bi2O3, respectively. Due to the multiple vacancies and valence states possessed by BiOCl0.9I0.1/x%β-Bi2O3, namely Bi5+, Bi(3-x)+, Bi5+–O, Bi3+–O, I- and I3-, the charge separation in photocatalysis reactions can be effectively promoted. The Mott-Schottky measurements indicate that the conduction band(CB) level of BiOCl0.9I0.1/15%β-Bi2O3 becomes more negative relative to that of BiOCl0.9I0.1, guaranteeing an advantageous effect on the redox ability of the photocatalyst. This study provides a new bright spot for the construction of high-performance photocatalysts.
基金Project supported by the Science Project of Harbin City(No. H2001-12)the Youth Foundation of School of Municipal and Environmental Engineering in Harbin Institute of Technology(No. 01306914).
文摘The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g,, it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84--24 mg/m^3 by O3/TiO2flJV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m^3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/（m^3.min） and Langmuir adsorption coefficient K of 0.0268 m^3/mg were obtained.
基金The National Basic Research Program (973) of China (No. 2004CB418505) the Foundation for Excellent Youth of HeilongjiangProvince
文摘In order to develop a catalyst with high activity for catalytic wet oxidation （CWO） process at room temperature and atmospheric pressure, Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst was prepared by consecutive impregnation method and the prepared parameters were optimized. The structure of the catalyst was characterized by BET, XRF, SEM and XPS technologies, and the actual wastewater was used to investigate the catalytic activity of Fe2O3-CeO2-TiO2/γ-Al2O3 in CWO process. The experimental results showed that the prepared catalyst exhibited good catalytic activity when the doping amount of Ti was 1.0 wt% （the weight ratio of Ti to carriers）, and the middle product, Fe2O3-CeO2-TiO2/γ-Al2O3, was calcined in 450℃ for 2 h. The CWO experiment for treating actual dye wastewater indicated that the COD, color and TOC of actual wastewater were decreased by 62.23%, 50.12% and 41.26% in 3 h, respectively, and the ratio of BOD5/COD was increased from 0.19 to 0.30.
基金supported by the National Key Technology R&D Program of China(No.2006BAJ04A06)the National High Technology Research and Development Program(863) of China(No.2003AA644020)the Program of Shanghai Subject Chief Scientist(No. 10XD1404200)
文摘The combination of leachate recirculation and aeration to landfill may be an efficient way for in-situ nitrogen removal.However,nitrogenous substances contained in the landfill layer are concomitantly transformed into N2O and NH3,leading to increased emissions into the atmosphere.In the present study,the emissions of N2O and NH3 were measured under conditions of fresh or partially stabilized refuse with or without leachate recirculation or intermittent aeration.The results showed that the largest N2O emission（12.4 mg-N/L of the column） was observed in the aerated column loaded with partially stabilized refuse and recycled with the leachate of low C/N ratio;while less than 0.33 mg-N/L of the column was produced in the other columns.N2O production was positively correlated with the prolonged aerobic time and negatively related with the C/N ratio in the recycled leachate.NH3 volatilization increased with enhanced gas flow and concentration of free ammonia in the leachate,and the highest cumulative volatilization quantity was 1.7 mg-N/L of the column.
基金Project(21271071)supported by the National Natural Science Foundation of ChinaProject(21306041)supported by the National Natural Science Young Foundation of China
文摘ZnO/Znml2O4 nanocomposites with heteronanostructures were successfully prepared by co-precipitation method. The as-prepared samples were characterized by HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photoeatalytic activities of the as-prepared samples were evaluated by the photocatalytic degradation of methyl orange and inactivation of Escherichia coli in suspension under the irradiation of the simulated sunlight. The effects of compositions, calcination temperatures, concentration ofphotocatalysts and light source on the photocatalytic activities were systematically studied. The results show that when the concentration of ZnO/ZnA1204 photocatalyst with the starting Zn to Al molar ratio of 1：1.5 calcined at 600 ℃ is 1.0 g/L, the maximum photocatalytic degradation rate of 98.5% can be obtained in 50 min under the irradiation of the simulated sunlight. Under the same conditions, an inactivation rate of 99.8% for E.coli is achieved in 60 min.
文摘A nanoheterojunction composite photocatalyst Bi2O3/TiO2 working under visible-light （λ≥ 420 nm） was prepared by combining two semiconductors Bi2O3 and TiO2 varying the Bi2O3/TiO2 molar ratio. Maleic acid was employed as an organic binder to unite Bi2O3 and TiO2 nanoparticles. The SEM, TEM, XRD and diffuse reflectance spectra were utilized to characterize the prepared Bi2O3/TiO2 nanoheterojunction. The nanocomposite exhibited unusual high photocatalytic activity in decomposing 2-propanol in gas phase and phenol in aqueous phase and, evolution of CO2 under visible light irradiation while the end members exhibited low photocatalytic activity. The composite was optimized to 5 mol% Bi2O3/TiO2. The remarkable high photocatalytic efficiency originates from the unique relative energy band position of Bi2O3 and TiO2 as well as the absorption of visible light by Bi2O3.
文摘Fe（II）/γ-Al2O3 powders synthesized using the dipping method were produced from a mixed aqueous solution containing aluminium oxide （γ-Al2O3） and iron（II）-precursor （FeSO4）, and used for photoFenton degradation of phthalocyanine dyes （PCs） under ultraviolet （UV） irradiation in an up-flow fluidized bed. The catalysts were characterized by XRD, ESCA, BET, EDS and SEM. The results showed that Fe2＋ ion was compounded on the γ-Al2O3 carder. The effects of different reaction parameters such as catalyst activity, dosage and solution pH on the decolorization of PCs were assessed. Results indicated that maximum decolorization （more than 95%） of PCs occurred with 20 wt% Fe（II）/γ-Al2O3 catalyst （dosage of 60 g/L） using a combination of UV irradiation and heterogeneous Fenton system. The degradation efficiency of PCs increases as pH decreases, exhibiting a maximum efficiency at pH 3.5. The recycled catalyst was capable of repeating three runs without a significant decrease in treatment efficiency, and this demonstrated the stability and reusability of catalyst.
文摘A coaxial dielectric barrier discharge (DBD) reactor was used for plasma-catalytic degradation of tetracycline hydrochloride over a series of Mn/γ-Al2O3 catalysts prepared by the incipient wetness impregnation method.The combination of plasma and the Mn/γ-Al2O3 catalysts significantly enhanced the degradation efficiency of tetracycline hydrochloride compared to the plasma process alone,with the 10% Mn/γ-Al2O3 catalyst exhibiting the best tetracycline hydrochloride degradation efficiency.A maximum degradation efficiency of 99.3% can be achieved after 5 min oxidation and a discharge power of 1.3 W,with only 69.7% by a single plasma process.The highest energy yield of the plasma-catalytic process is 91.7 g kWh-1.Probable reaction mechanisms of the plasma-catalytic removal of tetracycline hydrochloride were also proposed.
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the Lorestan University and Iran Nanotechnology Initiative Council (INIC) for their financial support
文摘A magnetic CoFe2O4/Cd S nanocomposite was prepared via one-step hydrothermal decomposition of cadmium diethanoldithiocarbamate complex on the surface of CoFe2O4 nanoparticles at a low temperature of 200 ℃.The nanocomposite was characterised by X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy,energy-dispersive X-ray spectroscopy（EDX）,UV-visible spectroscopy,transmission electron microscopy（TEM）,N2 gas sorption analysis,X-ray photoelectron spectroscopy（XPS）,and vibrating sample magnetometry.The FT-IR,XRD,EDX and XPS results confirmed the formation of the CoFe2O4/Cd S nanocomposite.Based on the TEM analysis,the CoFe2O4/Cd S nanocomposite constituted nearly uniform,sphere-like nanoparticles of ～20 nm in size.The optical absorption spectrum of the CoFe2O4/Cd S nanocomposite displayed a band gap of 2.21 e V,which made it a suitable candidate for application in sono/photocatalytic degradation of organic pollutants.Accordingly,the sonocatalytic activity of the CoFe2O4/Cd S nanocomposite was evaluated towards the H2O2-assisted degradation of methylene blue,rhodamine B,and methyl orange under ultrasonic irradiation.The nanocomposite displayed excellent sonocatalytic activity towards the degradation of all dyes examined—the dyes were completely decomposed within 5–9 min.Furthermore,a comparison study revealed that the CoFe2O4/Cd S nanocomposite is a more efficient sonocatalyst than pure Cd S;thus,adopting the nanocomposite approach is an excellent means to improve the sonoactivity of Cd S.Moreover,the magnetic properties displayed by the CoFe2O4/Cd S nanocomposite allow easy retrieval of the catalyst from the reaction mixture for subsequent uses.
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.
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.
