Powder quartz(PQ)/nano-TiO_2 composite was prepared by a mechanochemical method. Based on as-prepared PQ/nano-TiO_2 composite, we prepared interior paints and investigated the degradation efficiency of formaldehyde(DE...Powder quartz(PQ)/nano-TiO_2 composite was prepared by a mechanochemical method. Based on as-prepared PQ/nano-TiO_2 composite, we prepared interior paints and investigated the degradation efficiency of formaldehyde(DEF). Scanning electron microscopy showed that nano-TiO_2 got well dispersed by the adding of PQ. Thermogravimetric analysis indicated that the mass ratio of 4:1 was a relatively good proportion for the most production of PQ/nano-TiO_2 composite. Fourier transform-infrared spectrometry showed that the peak position of Ti-O-Si bond varied with the milling time. At the early stage, no characteristic peak of Ti-O-Si bond was observed, while at the later stage, new peaks at 902 cm^(-1) and 937 cm^(-1) appeared. Meanwhile, PQ/nano-TiO_2 composite-based interior paint exhibited significant DEF of 96.3% compared to that consisting of sole nanoTiO_2 of 92.0% under visible light illumination. As an abundant mineral resource, PQ would make interior paints with HCHO purifying effect much more efficient and cheaper.展开更多
The mechanism for tourmaline powder improving the photocatalysis effect of nano-TiO2 was studied by electron-spin resonance (ESR). It is found that the intensity of the signal of hydroxyl free radical produced by the ...The mechanism for tourmaline powder improving the photocatalysis effect of nano-TiO2 was studied by electron-spin resonance (ESR). It is found that the intensity of the signal of hydroxyl free radical produced by the mixture of the tourmaline and nano-TiO2 through 355nm wavelength ultraviolet radiating is increased. Under natural light, the mixture of nano TiO2 and tourmaline powder in a certain weight ratio can improve the effect of decomposing methyl orange that proved that the ESR result was right. The tourmaline particle could promote the photocatalysis of nano-TiO2. This result may be due to the surface electric field of the tourmaline, which can absorb the particle of nano-TiO2 and make the electron inspired by photon transfer from the inner of nano-TiO2 particle to its surface, and even make the electron transfer into tourmaline particle.展开更多
Cell surface of aquatic organisms constitutes a primary site for the interaction and a barrier for the nano-TiO_2 biological effects.In the present study,the biological effects of nano-TiO_2 on a unicellular green alg...Cell surface of aquatic organisms constitutes a primary site for the interaction and a barrier for the nano-TiO_2 biological effects.In the present study,the biological effects of nano-TiO_2 on a unicellular green algae Chlamydomonas reinhardtii were studied by observing the changes of the cell surface morphology and functional groups under UV or natural light.By SEM,the cell surface morphology of C.reinhardtii was changed under UV light,nano-TiO_2 with UV light or natural light,which indicated that photocatalysis damaged cell surface.It was also observed that cell surface was surrounded by TiO_2 nanoparticles.The ATR-FTIR spectra showed that the peaks of functional groups such as C-N,-C=O,-C-O-C and P=O,which were the important components of cell wall and membrane,were all depressed by the photocatalysis of nano-TiO_2 under UV light or natural light.The photocatalysis of nano-TiO_2 promoted peroxidation of functional groups on the surface of C.reinhardtii cells,which led to the damages of cell wall and membrane.展开更多
Mn:ZnSe/ZnS/L-Cys core-shell quantum dots(QDs)sensitized La-doped nano-TiO2 thin film(QDSTF)was prepared.X-ray photoelectron spectroscopy(XPS),nanosecond transient photovoltaic(TPV),and steady state surface photovolta...Mn:ZnSe/ZnS/L-Cys core-shell quantum dots(QDs)sensitized La-doped nano-TiO2 thin film(QDSTF)was prepared.X-ray photoelectron spectroscopy(XPS),nanosecond transient photovoltaic(TPV),and steady state surface photovoltaic(SPV)technologies were used for probing the photoelectron behaviors in the Mn-doped QDSTF.The results revealed that the Mn-doped QDSTF had a p-type TPV characteristic.The bottom of the conduction band of the QDs as a sensitizer was just 0.86 eV above that of the La-doped nano-TiO2 thin film,while the acceptor level of the doped Mn2+ions was located at about 0.39 eV below and near the bottom of the conduction band of the QDs.The intensity of the SPV response of the Mn-doped QDSTF at a specific wavelength was ~2.1 times higher than that of the undoped QDSTF.The region of the SPV response of the Mn-doped QDSTF was extended by 191 nm to almost the whole visible region as compared with the undoped QDSTF one.And the region of the TPV response of the Mn-doped QDSTF was also obviously wider than that of the undoped QDSTF.These PV characteristics of the Mn-doped QDSTF may be due to the prolonged lifetime and extended diffusion length of photogenerated free charge carriers injected into the sensitized La-doped nano-TiO2 thin film.展开更多
Nano-TiO_2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO_2 dosage and initial p H of the wastewate...Nano-TiO_2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO_2 dosage and initial p H of the wastewater on the removal rate of COD were tested. The GC/MS and EEM techniques were used to qualitatively analyze organic compounds in the wastewater before and after treatment. The result showed that after the biologically treated chemical comprehensive wastewater was treated by nano-TiO_2 photocatalytic oxidation under the conditions of reaction time 3 h,nano-TiO_2 dosage 8 g/L,and pH 8. 0,the effluent COD was 61. 9 mg/L and its removal rate was 63. 8%. Additionally,the species of organic pollutants reduced from 12 to 6. Meanwhile,the content of humic-like and fulvic-like substances dropped dramatically.展开更多
基金Funded by the National Natural Science Foundation of China(No.41130746)
文摘Powder quartz(PQ)/nano-TiO_2 composite was prepared by a mechanochemical method. Based on as-prepared PQ/nano-TiO_2 composite, we prepared interior paints and investigated the degradation efficiency of formaldehyde(DEF). Scanning electron microscopy showed that nano-TiO_2 got well dispersed by the adding of PQ. Thermogravimetric analysis indicated that the mass ratio of 4:1 was a relatively good proportion for the most production of PQ/nano-TiO_2 composite. Fourier transform-infrared spectrometry showed that the peak position of Ti-O-Si bond varied with the milling time. At the early stage, no characteristic peak of Ti-O-Si bond was observed, while at the later stage, new peaks at 902 cm^(-1) and 937 cm^(-1) appeared. Meanwhile, PQ/nano-TiO_2 composite-based interior paint exhibited significant DEF of 96.3% compared to that consisting of sole nanoTiO_2 of 92.0% under visible light illumination. As an abundant mineral resource, PQ would make interior paints with HCHO purifying effect much more efficient and cheaper.
基金The National Nature Science Foundation of China (50272062) and Beijing City Science Foundation of China(2042021)
文摘The mechanism for tourmaline powder improving the photocatalysis effect of nano-TiO2 was studied by electron-spin resonance (ESR). It is found that the intensity of the signal of hydroxyl free radical produced by the mixture of the tourmaline and nano-TiO2 through 355nm wavelength ultraviolet radiating is increased. Under natural light, the mixture of nano TiO2 and tourmaline powder in a certain weight ratio can improve the effect of decomposing methyl orange that proved that the ESR result was right. The tourmaline particle could promote the photocatalysis of nano-TiO2. This result may be due to the surface electric field of the tourmaline, which can absorb the particle of nano-TiO2 and make the electron inspired by photon transfer from the inner of nano-TiO2 particle to its surface, and even make the electron transfer into tourmaline particle.
基金Funded by the National Natural Science Foundation of China(No.51579159)
文摘Cell surface of aquatic organisms constitutes a primary site for the interaction and a barrier for the nano-TiO_2 biological effects.In the present study,the biological effects of nano-TiO_2 on a unicellular green algae Chlamydomonas reinhardtii were studied by observing the changes of the cell surface morphology and functional groups under UV or natural light.By SEM,the cell surface morphology of C.reinhardtii was changed under UV light,nano-TiO_2 with UV light or natural light,which indicated that photocatalysis damaged cell surface.It was also observed that cell surface was surrounded by TiO_2 nanoparticles.The ATR-FTIR spectra showed that the peaks of functional groups such as C-N,-C=O,-C-O-C and P=O,which were the important components of cell wall and membrane,were all depressed by the photocatalysis of nano-TiO_2 under UV light or natural light.The photocatalysis of nano-TiO_2 promoted peroxidation of functional groups on the surface of C.reinhardtii cells,which led to the damages of cell wall and membrane.
基金Project supported by the Natural Science Foundation of Hebei Province,China(Grant No.E2017203029)。
文摘Mn:ZnSe/ZnS/L-Cys core-shell quantum dots(QDs)sensitized La-doped nano-TiO2 thin film(QDSTF)was prepared.X-ray photoelectron spectroscopy(XPS),nanosecond transient photovoltaic(TPV),and steady state surface photovoltaic(SPV)technologies were used for probing the photoelectron behaviors in the Mn-doped QDSTF.The results revealed that the Mn-doped QDSTF had a p-type TPV characteristic.The bottom of the conduction band of the QDs as a sensitizer was just 0.86 eV above that of the La-doped nano-TiO2 thin film,while the acceptor level of the doped Mn2+ions was located at about 0.39 eV below and near the bottom of the conduction band of the QDs.The intensity of the SPV response of the Mn-doped QDSTF at a specific wavelength was ~2.1 times higher than that of the undoped QDSTF.The region of the SPV response of the Mn-doped QDSTF was extended by 191 nm to almost the whole visible region as compared with the undoped QDSTF one.And the region of the TPV response of the Mn-doped QDSTF was also obviously wider than that of the undoped QDSTF.These PV characteristics of the Mn-doped QDSTF may be due to the prolonged lifetime and extended diffusion length of photogenerated free charge carriers injected into the sensitized La-doped nano-TiO2 thin film.
文摘Nano-TiO_2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO_2 dosage and initial p H of the wastewater on the removal rate of COD were tested. The GC/MS and EEM techniques were used to qualitatively analyze organic compounds in the wastewater before and after treatment. The result showed that after the biologically treated chemical comprehensive wastewater was treated by nano-TiO_2 photocatalytic oxidation under the conditions of reaction time 3 h,nano-TiO_2 dosage 8 g/L,and pH 8. 0,the effluent COD was 61. 9 mg/L and its removal rate was 63. 8%. Additionally,the species of organic pollutants reduced from 12 to 6. Meanwhile,the content of humic-like and fulvic-like substances dropped dramatically.
基金Project supported by the Foundation of National Key Technologies Research and Development Program-Shanghai World Expo Special Project (Grant No.04DZ05803)
