A novel composite electrode was constructed by pressing together Co3O4 and graphite and it was used as the cathode in an electro-Fenton-like (EFL) system. The poor electron transport characteristic of Co3O4 was overco...A novel composite electrode was constructed by pressing together Co3O4 and graphite and it was used as the cathode in an electro-Fenton-like (EFL) system. The poor electron transport characteristic of Co3O4 was overcome by incorporating graphite. In situ electro-catalytic generation of hydroxyl radicals (·OH) occurred at high current efficiencies from pH 2-10, extending the traditional Fenton reaction pH range. Cyclic voltammetry and AC impedance spectrometry were used to characterize the composite electrode. The ability of the EFL system to degrade organic compounds was investigated using sulforhodamine B (SRB) and 2,4-dichlorophenol (2,4-DCP) as probes. Decoloration of SRB (1.0×10-5 mol/L) was complete (100%) in 150 min and SRB was effectively degraded from pH 2-10. The decomposition of SRB was studied using Fourier transform infrared spectroscopy (FT-IR) and total organic carbon (TOC) analysis and results indicated that the final degradation products were carbon dioxide, carboxylic acids and amines. The EFL system also decomposed 2,4-DCP and the degradation was 98.6% in 240 min. Electro-catalytic degradation of SRB occurs by a ·OH mechanism. After 5 times reused, the degradation rate of SRB did not significantly slow down. The electrode shows excellent potential for use in advanced oxidation processes (AOPs) used to treat persistent organic pollutants (POPs) in wastewater.展开更多
Silica gel-supported Fe(II) (SiOFe) was prepared and used for heterogeneous degradation of sulforho-damine B (SRB) and 2,4-dichlorophenol (DCP) under visible irradiation (λ > 420 nm) as an effective catalyst. UVvi...Silica gel-supported Fe(II) (SiOFe) was prepared and used for heterogeneous degradation of sulforho-damine B (SRB) and 2,4-dichlorophenol (DCP) under visible irradiation (λ > 420 nm) as an effective catalyst. UVvisible spectra, and infrared Spectrophotometry (IR), fluorescence, total organic carbon (TOC) and electron spin resonance (ESR) measurements were employed to analyze the photoreaction products. The results showed that SRB could be efficiently degraded by SiOFe/H2O2 system under visible irradiation with 100% decolorization and 72.3% TOC removal after 180 min illumination. The results of ESR and fluorescence measurements indicated that the oxidative process was predominated mainly by the hydroxyl radical (·OH) generated in the system.展开更多
A TiO2@SiO2 hybrid support was prepared by the sol-precipitation method using n-octylamine as a template.The photocatalyst manganese phthalocyanine tetrasulfonic acid (MnPcS) was immobilized on the support to form MnP...A TiO2@SiO2 hybrid support was prepared by the sol-precipitation method using n-octylamine as a template.The photocatalyst manganese phthalocyanine tetrasulfonic acid (MnPcS) was immobilized on the support to form MnPcS-TiO2@SiO2.X-ray diffraction (XRD) and UV-Visible diffuse reflectance spectra (UV-Vis DRS) were employed to characterize the catalyst.The photocatalytic degradation of rhodamine B (RhB) and the catalytic oxidation of o-phenylenediamine (OPDA) under visible light irradiation were used as probe reactions.The mineralization efficiency and the degradation mechanism were evaluated using chemical oxygen demand (COD Cr) assays and electron spin resonance (ESR),respectively.RhB was efficiently degraded by immobilized MnPcS-TiO2@SiO2 under visible light irradiation.Complete decolorization of RhB occurred after 240 min of irradiation and 64.02% COD Cr removal occurred after 24 h of irradiation.ESR results indicated that the oxidation process was dominated by the hydroxyl radical (·OH) and superoxide radical (O-·2) generated in the system.展开更多
A hydrophobic complex of Cu2+[bis-salicylic aldehyde-o-phenylenediamine],Cu-SPA,was prepared and used as a heterogeneous photocatalyst to degrade organic pollutants in water under visible irradiation(420 nm)at neutral...A hydrophobic complex of Cu2+[bis-salicylic aldehyde-o-phenylenediamine],Cu-SPA,was prepared and used as a heterogeneous photocatalyst to degrade organic pollutants in water under visible irradiation(420 nm)at neutral pH.The structure of complex was characterized by using nuclear magnetic resonance(NMR),elemental analysis,IR and UV-vis spectrometries.Degradation of Rhodamine B(RhB),Sulforhodamine B(SRB)and Benzoic acid(BA)in water were used as model reactions to evaluate the photocatalytic activities of Cu-SPA.The results indicated that RhB and SRB were easily adsorbed on the hydrophobic surface of Cu-SPA from aqueous solution(the maximum adsorption amount:Qmax=11.09 and 8.05μmol/g,respectively).Under visible irradiation,RhB and SRB were decolorized completely after 210 and 240 min,respectively,and BA was removed completely after 5 h.The efficiency of H2O2was>95%,in contrast to that of the reaction without catalyst or light(<20%).In water soluble medium,the hydrophobic Cu-SPA can be used more than 6 cycles.ESR results and the behavior of cyclic voltammetry showed that,in the reaction process,Cu2+-SPA was reduced to intermediate state Cu+-SPA firstly,which was extremely unstable and reacted rapidly with H2O2,leading to high reactive oxygen species(·OH radical)to degrade the substrate.展开更多
The mechanism of oxidative damage to deoxyribonucleic acid (DNA) by iron-containing mesoporous molecular sieves (MCM-41) irradiated with visible light was elucidated. Fe-loaded MCM-41 (Fe/MCM-41) was used as a photoca...The mechanism of oxidative damage to deoxyribonucleic acid (DNA) by iron-containing mesoporous molecular sieves (MCM-41) irradiated with visible light was elucidated. Fe-loaded MCM-41 (Fe/MCM-41) was used as a photocatalyst and the damage to calf thymus DNA caused by hydrogen peroxide (H2O2) was studied. The damage and extent of oxidation of DNA were measured by high-performance liquid chromatography (HPLC) and intermediate products were detected by HPLC/electrospray ionization tandem mass spectrometry. Electron spin resonance was used to detect changes in reactive oxygen species and peroxidase catalytic spectrophotometry was used to determine the concentration of H2O2. The results indicated that Fe/MCM-41 efficiently activated H2O2 in solution at pH 4.0-8.0 under irradiation with visible light. The photocatalytic system degraded DNA most effectively at pH 5.0-6.0 but also operated at pH 8.0. At pH 4.2, the degree of DNA damage reached 25.65% after 5 h and the kinetic constant was 5.89×10 2 min 1. Damage to DNA was predominantly caused by hydroxyl radicals generated in the system. The mechanism of DNA damage is of potential concern to human health because it can occur in neutral solutions irradiated by visible light.展开更多
Visible light irradiation combined with homogeneous iron and/or hydrogen peroxide to degrade organic dye rhodamine B (RhB) and small molecular compound 2,4-dichlorophenol (2,4-DCP) in a home-made bottle reactor was as...Visible light irradiation combined with homogeneous iron and/or hydrogen peroxide to degrade organic dye rhodamine B (RhB) and small molecular compound 2,4-dichlorophenol (2,4-DCP) in a home-made bottle reactor was assessed. The concen-tration of oxidize species, Fe3+ and Fe2+ were determined during the degradation process. The results demonstrated that visible light irradiation combined with electro-Fenton improved the degradation efficiency. Moreover, both RhB and 2,4-DCP were mineralized during visible light synergistic electro-Fenton oxidation process. 95.0% TOC (total organic carbon) removal rate of RhB occurred after 90 min and 96.7% of COD (chemical oxygen demand) removal rate after 65 min of irradiation. 91.3% TOC removal rate of 2,4-DCP occurred after 16 h of irradiation and 99.9% COD removal rate occurred after 12 h of illumination. The degradation and oxidation process was dominated by the hydroxyl radical ( · OH) generated in the system. Both the impressed electricity and dye sensitization by visible light facilitated the conversion between Fe3+ and Fe 2+ , thus, improving Fenton reaction efficiency.展开更多
In this paper, the oxidative degradation of 2, 4-dichlor- ophenoxyacetic acid （2, 4-D） using Mn2＋/H2O2 reagent under UV irradiation was studied. The results show that 2, 4-D was degraded more completely in Mn〉/H2O...In this paper, the oxidative degradation of 2, 4-dichlor- ophenoxyacetic acid （2, 4-D） using Mn2＋/H2O2 reagent under UV irradiation was studied. The results show that 2, 4-D was degraded more completely in Mn〉/H2O2 solution than traditional Fenton solutions. The effects of the concentration of Mn2＋, H2O2 and pH were also investigated. And under the optimal condition of CMn2＋ 1.48×10^-4mol/L, CH2O2 8.99×10^-5mol/L and pH 3.38, the formation of .OH was the most, both the decomposition rate of H202 and the degradation rate of 2, 4-D were the fastest. In addi- tion, the photoreaction process was monitored using spin-trapping electron paramagnetic resonance （EPR）, and the results indicated that the oxidative process was predominated mainly by the hydroxyl radical （＊ OH） gennerated in the system.展开更多
基金supported by the National Natural Science Foundation of China (21177072, 21207079)the Educational Commission for Distinguished Group of Hubei Province, China (T200703)the Natural Science Foundation for Innovation Group of Hubei Province, China(2009CDA020)
文摘A novel composite electrode was constructed by pressing together Co3O4 and graphite and it was used as the cathode in an electro-Fenton-like (EFL) system. The poor electron transport characteristic of Co3O4 was overcome by incorporating graphite. In situ electro-catalytic generation of hydroxyl radicals (·OH) occurred at high current efficiencies from pH 2-10, extending the traditional Fenton reaction pH range. Cyclic voltammetry and AC impedance spectrometry were used to characterize the composite electrode. The ability of the EFL system to degrade organic compounds was investigated using sulforhodamine B (SRB) and 2,4-dichlorophenol (2,4-DCP) as probes. Decoloration of SRB (1.0×10-5 mol/L) was complete (100%) in 150 min and SRB was effectively degraded from pH 2-10. The decomposition of SRB was studied using Fourier transform infrared spectroscopy (FT-IR) and total organic carbon (TOC) analysis and results indicated that the final degradation products were carbon dioxide, carboxylic acids and amines. The EFL system also decomposed 2,4-DCP and the degradation was 98.6% in 240 min. Electro-catalytic degradation of SRB occurs by a ·OH mechanism. After 5 times reused, the degradation rate of SRB did not significantly slow down. The electrode shows excellent potential for use in advanced oxidation processes (AOPs) used to treat persistent organic pollutants (POPs) in wastewater.
基金the National Natural Science Foundation of China (Grant Nos. 50639070 and 20373074)the Youth Outstanding Foundation of Hubei Province of China (Grant No. 2005ABB030)the Natural Science Research Plan Project of Education Office of Hubei Province of China (Grant No. 2004Z001)
文摘Silica gel-supported Fe(II) (SiOFe) was prepared and used for heterogeneous degradation of sulforho-damine B (SRB) and 2,4-dichlorophenol (DCP) under visible irradiation (λ > 420 nm) as an effective catalyst. UVvisible spectra, and infrared Spectrophotometry (IR), fluorescence, total organic carbon (TOC) and electron spin resonance (ESR) measurements were employed to analyze the photoreaction products. The results showed that SRB could be efficiently degraded by SiOFe/H2O2 system under visible irradiation with 100% decolorization and 72.3% TOC removal after 180 min illumination. The results of ESR and fluorescence measurements indicated that the oxidative process was predominated mainly by the hydroxyl radical (·OH) generated in the system.
基金supported by the National Natural Science Foundation of China(20877048)the National Basic Research Program of China(2008CB417206)the Innovation Group Project of Hubei Provincial Natural Science Foundation(2009CDA020)
文摘A TiO2@SiO2 hybrid support was prepared by the sol-precipitation method using n-octylamine as a template.The photocatalyst manganese phthalocyanine tetrasulfonic acid (MnPcS) was immobilized on the support to form MnPcS-TiO2@SiO2.X-ray diffraction (XRD) and UV-Visible diffuse reflectance spectra (UV-Vis DRS) were employed to characterize the catalyst.The photocatalytic degradation of rhodamine B (RhB) and the catalytic oxidation of o-phenylenediamine (OPDA) under visible light irradiation were used as probe reactions.The mineralization efficiency and the degradation mechanism were evaluated using chemical oxygen demand (COD Cr) assays and electron spin resonance (ESR),respectively.RhB was efficiently degraded by immobilized MnPcS-TiO2@SiO2 under visible light irradiation.Complete decolorization of RhB occurred after 240 min of irradiation and 64.02% COD Cr removal occurred after 24 h of irradiation.ESR results indicated that the oxidation process was dominated by the hydroxyl radical (·OH) and superoxide radical (O-·2) generated in the system.
基金supported by the National Natural Science Foundation of China(21207079,21307073,21177072,21377067)
文摘A hydrophobic complex of Cu2+[bis-salicylic aldehyde-o-phenylenediamine],Cu-SPA,was prepared and used as a heterogeneous photocatalyst to degrade organic pollutants in water under visible irradiation(420 nm)at neutral pH.The structure of complex was characterized by using nuclear magnetic resonance(NMR),elemental analysis,IR and UV-vis spectrometries.Degradation of Rhodamine B(RhB),Sulforhodamine B(SRB)and Benzoic acid(BA)in water were used as model reactions to evaluate the photocatalytic activities of Cu-SPA.The results indicated that RhB and SRB were easily adsorbed on the hydrophobic surface of Cu-SPA from aqueous solution(the maximum adsorption amount:Qmax=11.09 and 8.05μmol/g,respectively).Under visible irradiation,RhB and SRB were decolorized completely after 210 and 240 min,respectively,and BA was removed completely after 5 h.The efficiency of H2O2was>95%,in contrast to that of the reaction without catalyst or light(<20%).In water soluble medium,the hydrophobic Cu-SPA can be used more than 6 cycles.ESR results and the behavior of cyclic voltammetry showed that,in the reaction process,Cu2+-SPA was reduced to intermediate state Cu+-SPA firstly,which was extremely unstable and reacted rapidly with H2O2,leading to high reactive oxygen species(·OH radical)to degrade the substrate.
基金supported by the National Natural Science Foundation of China (20877048, and 21177072)the National Basic Research Program of China (2008CB417206)the Innovation Group Project of Hubei Province Natural Science Foundation(2009CDA020, and T200703)
文摘The mechanism of oxidative damage to deoxyribonucleic acid (DNA) by iron-containing mesoporous molecular sieves (MCM-41) irradiated with visible light was elucidated. Fe-loaded MCM-41 (Fe/MCM-41) was used as a photocatalyst and the damage to calf thymus DNA caused by hydrogen peroxide (H2O2) was studied. The damage and extent of oxidation of DNA were measured by high-performance liquid chromatography (HPLC) and intermediate products were detected by HPLC/electrospray ionization tandem mass spectrometry. Electron spin resonance was used to detect changes in reactive oxygen species and peroxidase catalytic spectrophotometry was used to determine the concentration of H2O2. The results indicated that Fe/MCM-41 efficiently activated H2O2 in solution at pH 4.0-8.0 under irradiation with visible light. The photocatalytic system degraded DNA most effectively at pH 5.0-6.0 but also operated at pH 8.0. At pH 4.2, the degree of DNA damage reached 25.65% after 5 h and the kinetic constant was 5.89×10 2 min 1. Damage to DNA was predominantly caused by hydroxyl radicals generated in the system. The mechanism of DNA damage is of potential concern to human health because it can occur in neutral solutions irradiated by visible light.
基金supported by China National Funds for Distinguished Young Scientists (50925932)the National Natural Science Foundation of China (21177072, 21207079)Open Foundation about Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission& Ministry of Education of Hubei Province (CHCL10007)
文摘Visible light irradiation combined with homogeneous iron and/or hydrogen peroxide to degrade organic dye rhodamine B (RhB) and small molecular compound 2,4-dichlorophenol (2,4-DCP) in a home-made bottle reactor was assessed. The concen-tration of oxidize species, Fe3+ and Fe2+ were determined during the degradation process. The results demonstrated that visible light irradiation combined with electro-Fenton improved the degradation efficiency. Moreover, both RhB and 2,4-DCP were mineralized during visible light synergistic electro-Fenton oxidation process. 95.0% TOC (total organic carbon) removal rate of RhB occurred after 90 min and 96.7% of COD (chemical oxygen demand) removal rate after 65 min of irradiation. 91.3% TOC removal rate of 2,4-DCP occurred after 16 h of irradiation and 99.9% COD removal rate occurred after 12 h of illumination. The degradation and oxidation process was dominated by the hydroxyl radical ( · OH) generated in the system. Both the impressed electricity and dye sensitization by visible light facilitated the conversion between Fe3+ and Fe 2+ , thus, improving Fenton reaction efficiency.
基金Supported by the National Basic Research Program of China (973 Program) (2008CB417206)the National Natural Science Foundation of China (20877048)Hydrology and National Key Laboratory Open Funds of Water Resources and Hydraulic Engineering Science(2006412311)
文摘In this paper, the oxidative degradation of 2, 4-dichlor- ophenoxyacetic acid （2, 4-D） using Mn2＋/H2O2 reagent under UV irradiation was studied. The results show that 2, 4-D was degraded more completely in Mn〉/H2O2 solution than traditional Fenton solutions. The effects of the concentration of Mn2＋, H2O2 and pH were also investigated. And under the optimal condition of CMn2＋ 1.48×10^-4mol/L, CH2O2 8.99×10^-5mol/L and pH 3.38, the formation of .OH was the most, both the decomposition rate of H202 and the degradation rate of 2, 4-D were the fastest. In addi- tion, the photoreaction process was monitored using spin-trapping electron paramagnetic resonance （EPR）, and the results indicated that the oxidative process was predominated mainly by the hydroxyl radical （＊ OH） gennerated in the system.
