CaTi_(2)O_(5)was selectively prepared by a solvothermal process without template and surfactant.The phase of the as-prepared samples was determined by X-ray diffraction(XRD).The microstructure was characterized by sca...CaTi_(2)O_(5)was selectively prepared by a solvothermal process without template and surfactant.The phase of the as-prepared samples was determined by X-ray diffraction(XRD).The microstructure was characterized by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Results found that pH values had a crucial effect on the crystal phase and shape evolution of the samples.CaTi_(2)O_(5)sample prepared at pH of 5.2 shows high efficient light harvesting,large surface area and crystallinity.Moreover,CaTi_(2)O_(5)shuttle-like sample shows good photocatalytic activity against methyl orange due to its longer and thinner shuttle-like morphology and high crystallinity,enhanced light harvesting and large surface area.The photocatalytic rate of CaTi_(2)O_(5)shuttle-like structure reaches 0.1988 min-1 for 25-min methyl orange degradation under the ultraviolet light irradiation and displays an excellent photostability with a degradation efficiency of 0.1952 min^(-1)after four cycles.展开更多
This paper focuses on the pathway,the kinetic laws and the mechanisms of BDE-47 photo-degradation in the environment.By changing the degradation conditions(such as light sources,solvents,inorganic salts and free radic...This paper focuses on the pathway,the kinetic laws and the mechanisms of BDE-47 photo-degradation in the environment.By changing the degradation conditions(such as light sources,solvents,inorganic salts and free radical scavengers)and analyzing the degradation products using gas chromatography(GC)and gas chromatography/mass spectrometry(GC/MS),a better understanding of the fate of 2,2',4,4'-Tetrabromodiphenyl ether(BDE-47)in the environment is obtained.Results show that(i)the degradation reactions of BDE-47 under four different types of light sources are well described by the first order kinetic equation(r≥0.9995);(ii)hydrogen-donating ability and light absorption property of an organic solvent have a joint influence on the kinetics of degradation of BDE-47,which makes the degradation rate constants of BDE-47 different in different solvents(hexane 0.2735,methanol 0.2720,toluene 0.1280,methanol/water(1:1)0.0673,acetonitrile 0.0471,acetone 0.0030);(iii)the types and quantities of detected degradation products of BDE-47 are different in different solvents,BDE-1 is found only in hexane solvent,BDE-3 is not found in toluene,the relative content of BDE-28 in toluene is the highest(91.3%);(iv)inorganic ions have different effects on the degradation of BDE-47,the half-life of 0.10 mmol Fe^(3+) is reduced by 46.1%compared with that without adding 0.10 mmol Fe^(3+),the half-life of 0.5 mmol NH_(4)^(+) is reduced by 46.7%compared with that without 0.5 mmol NH4 t,50 mg/L TBA can increase the halflife by 5.1%compared with no addition.展开更多
基金the National Natural Science Foundation of China(No.51502119)Jiangxi Major Natural Science Foundation(Nos.20152ACB21022 and 20161BBH80048)。
文摘CaTi_(2)O_(5)was selectively prepared by a solvothermal process without template and surfactant.The phase of the as-prepared samples was determined by X-ray diffraction(XRD).The microstructure was characterized by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Results found that pH values had a crucial effect on the crystal phase and shape evolution of the samples.CaTi_(2)O_(5)sample prepared at pH of 5.2 shows high efficient light harvesting,large surface area and crystallinity.Moreover,CaTi_(2)O_(5)shuttle-like sample shows good photocatalytic activity against methyl orange due to its longer and thinner shuttle-like morphology and high crystallinity,enhanced light harvesting and large surface area.The photocatalytic rate of CaTi_(2)O_(5)shuttle-like structure reaches 0.1988 min-1 for 25-min methyl orange degradation under the ultraviolet light irradiation and displays an excellent photostability with a degradation efficiency of 0.1952 min^(-1)after four cycles.
基金This work is supported by the National Natural Science Foundation of China(No.21377033),and the Key Program of Hebei Education Department(No.ZD20131046).
文摘This paper focuses on the pathway,the kinetic laws and the mechanisms of BDE-47 photo-degradation in the environment.By changing the degradation conditions(such as light sources,solvents,inorganic salts and free radical scavengers)and analyzing the degradation products using gas chromatography(GC)and gas chromatography/mass spectrometry(GC/MS),a better understanding of the fate of 2,2',4,4'-Tetrabromodiphenyl ether(BDE-47)in the environment is obtained.Results show that(i)the degradation reactions of BDE-47 under four different types of light sources are well described by the first order kinetic equation(r≥0.9995);(ii)hydrogen-donating ability and light absorption property of an organic solvent have a joint influence on the kinetics of degradation of BDE-47,which makes the degradation rate constants of BDE-47 different in different solvents(hexane 0.2735,methanol 0.2720,toluene 0.1280,methanol/water(1:1)0.0673,acetonitrile 0.0471,acetone 0.0030);(iii)the types and quantities of detected degradation products of BDE-47 are different in different solvents,BDE-1 is found only in hexane solvent,BDE-3 is not found in toluene,the relative content of BDE-28 in toluene is the highest(91.3%);(iv)inorganic ions have different effects on the degradation of BDE-47,the half-life of 0.10 mmol Fe^(3+) is reduced by 46.1%compared with that without adding 0.10 mmol Fe^(3+),the half-life of 0.5 mmol NH_(4)^(+) is reduced by 46.7%compared with that without 0.5 mmol NH4 t,50 mg/L TBA can increase the halflife by 5.1%compared with no addition.
