Energy band gap of titanium dioxide(TiO_2) semiconductor plays significant roles in many practical applications of the semiconductor and determines its appropriateness in technological and industrial applications such...Energy band gap of titanium dioxide(TiO_2) semiconductor plays significant roles in many practical applications of the semiconductor and determines its appropriateness in technological and industrial applications such as UV absorption, pigment,photo-catalysis, pollution control systems and solar cells among others. Substitution of impurities into crystal lattice structure is the most commonly used method of tuning the band gap of TiO_2 for specific application and eventually leads to lattice distortion. This work utilizes the distortion in the lattice structure to estimate the band gap of doped TiO_2, for the first time, through hybridization of a particle swarm optimization algorithm(PSO) with a support vector regression(SVR) algorithm for developing a PSO-SVR model. The precision and accuracy of the developed PSO-SVR model was further justified by applying the model for estimating the effect of cobalt-sulfur co-doping, nickel-iodine co-doping, tungsten and indium doping on the band gap of TiO_2 and excellent agreement with the experimentally reported values was achieved. Practical implementation of the proposed PSO-SVR model would further widen the applications of the semiconductor and reduce the experimental stress involved in band gap determination of TiO_2.展开更多
Nanosized TiO 2 particles, synthesized by microemulsion mediated method, were characterized by XRD, TEM, EDS and BET. To judge the activity of TiO 2 particles, the photocatalytic destruction of phenol in aerated su...Nanosized TiO 2 particles, synthesized by microemulsion mediated method, were characterized by XRD, TEM, EDS and BET. To judge the activity of TiO 2 particles, the photocatalytic destruction of phenol in aerated suspension was studied. The result shows that the photocatalytic activity of lab made nanometer anatase TiO 2 is comparable to or higher than that of commercial titania particles. The effects of some processing parameters such as TiO 2 content, oxygen flow rate, pH value on phenol removal were also investigated. The experimental results indicate that there is an optimum value for the TiO 2 content. Sufficient O 2 supply is needed, but too high gas flow rate induces large bubbles that eliminate the gas residence time and the gas/liquid contact interface. The pH value of the phenol solutions has a complex effect on the photocatalytic activity of the particles.展开更多
In the presence of titanium dioxide powder, cross-linking reaction between commercial polyvinyl alcohol(PVA)-based macromonomer and acrylic acid(AA) was initiated with potassium persulfate in an emulsifying system. As...In the presence of titanium dioxide powder, cross-linking reaction between commercial polyvinyl alcohol(PVA)-based macromonomer and acrylic acid(AA) was initiated with potassium persulfate in an emulsifying system. As a result, PVA-AA/TiO2 composite gel particles were obtained. The morphology and composition of the particles were analyzed with scanning electron microscopy(SEM), energy scattering x-ray spectroscopy(EDS), Fourier infrared spectroscopy(FTIR), and thermogravimetric analysis(TGA). The analysis results confirmed that the particles were the expected ones. TiO2 was dispersed homogeneously within the spheroidal particles. Compared to the control gel, the composite gel particles not only contained Ti element but also showed higher thermal stability. In addition, the photo-catalytic behavior of the particles for the degradation of methyl orange contained in aqueous solution was examined. The particles exhibited photocatalytic characteristic for the degradation of the model dye, which could be modulated by simply varying the amount of cross-linking agent or TiO2. The photo-catalytic degradation percentage of methyl orange maintained at 91%-96% after using the particles three times, which indicated that TiO2 could played its role repeatedly via being fixated within polyvinyl alcohol-based gel.展开更多
It was tried to prepare composite particles made of polymer and two kinds of solid powders by forming Pickeringemulsion followed by the drying-in-liquid method and to investigate how the stepwise addition of solid pow...It was tried to prepare composite particles made of polymer and two kinds of solid powders by forming Pickeringemulsion followed by the drying-in-liquid method and to investigate how the stepwise addition of solid powders affected the contained ratio and adhesion ratio of solid powders and the structure of composite particles. Limonene oil dissolving expanded polystyrene and ethylene glycol were adopted as the dispersed phase and the continuous phase, respectively. Magnetite and titanium dioxide were used as solid powders. Magnetite was added before or after formation of the (O/W) dispersion. Titanium dioxide was added at the various elapsed times from addition of magnetite. Titanium dioxide adhered only on the surface of composite particles irrespective of addition time. At the earlier addition of both solid powders, the surface-covering type composite particles were prepared. At the latter addition of titanium dioxide, a part of magnetite adhered on the surface and the remainder was dispersed into composite particle.展开更多
The effect of inhaled nano-TiO2 on lung histology and serum biochemical indexes is evaluated in healthy and adult Kunming mice（eight in each group）after exposure to TiO2 aerosols（1 500 mg/m3）in a sealed chamber.An...The effect of inhaled nano-TiO2 on lung histology and serum biochemical indexes is evaluated in healthy and adult Kunming mice（eight in each group）after exposure to TiO2 aerosols（1 500 mg/m3）in a sealed chamber.Another eight mice are exposed to indoor air to be served as a control group.Lung tissue and blood are collected after euthanizing the animals.The results show that lactate dehydrogenase（LDH）activity increases in all experimental groups.Alanine aminotransferase（ALT）activity and blood urea nitrogen（BUN）levels are increased in the group exposed to TiO2 aerosols for 28 d,and creatinine（Cr）levels are increased in 14 d and 28 d samples（P0.05）.No obvious changes are observed in other serum indexes.Lungs of mice exposed to 28 d exposure show significant but moderate increase in pulmonary inflammation,and many TiO2 particles are found in the interstitium of pulmonary alveoli.展开更多
Titanium dioxide is a photocatalytically active substance used as a white pigment for cosmetics.In sunlight,titanium dioxide catalyzes decomposition of a certain amount of sebum on the skin by ultraviolet radiation.He...Titanium dioxide is a photocatalytically active substance used as a white pigment for cosmetics.In sunlight,titanium dioxide catalyzes decomposition of a certain amount of sebum on the skin by ultraviolet radiation.Herein,a novel white pigment for use in cosmetics was developed from titanium dioxide and phosphoric acid at pH=4 with and without glycerin,sodium lactate,lactic acid,and urea.The chemical composition,powder properties,photocatalytic activity,color phase,and smoothness of the samples were studied.Addition of glycerin led to a decline in the intensity of the X-ray diffraction(XRD)peak of TiO_(2) relative to that of the other samples.The particle size of the materials prepared with and without additives was 0.3μm;however,extensive aggregation was observed in the obtained materials.The photocatalytic activity of TiO_(2) was inhibited by phosphoric acid treatment.The materials prepared with sodium lactate,lactic acid,and glycerin exhibited higher photocatalytic activity than that prepared without additives.The obtained materials showed a high reflectance in the range of visible light,and the L^(*)values in L^(*)a^(*)b^(*) color space were high(where L^(*)defines lightness,a^(*) denotes the red/green value,and b^(*) the yellow/blue value).These results indicate that the samples prepared in this work are suitable for use as white pigments.展开更多
Presence of external electrical field plays a vital role in heat transfer and fluid flow phenomena. Keeping this in view present article is a numerical investigation of stagnation point flow of water based nanoparticl...Presence of external electrical field plays a vital role in heat transfer and fluid flow phenomena. Keeping this in view present article is a numerical investigation of stagnation point flow of water based nanoparticles suspended fluid under the influence of induced magnetic field. A detailed comparative analysis has been performed by considering Copper and Titanium dioxide nanoparticles. Utilization of similarity analysis leads to a simplified system of coupled nonlinear differential equations, which has been tackled numerically by means of shooting technique followed by Runge-Kutta of order 5. The solutions are computed correct up to 6 decimal places. Influence of pertinent parameters is examined for fluid flow, induced magnetic field, and temperature profile. One of the key findings includes that magnetic parameter plays a vital role in directing fluid flow and lowering temperature profile. Moreover, it is concluded that Cu-water based nanofluid high thermal conductivity contributes in enhancing heat transfer efficiently.展开更多
基金The support of King Fahd University of Petroleum and Minerals
文摘Energy band gap of titanium dioxide(TiO_2) semiconductor plays significant roles in many practical applications of the semiconductor and determines its appropriateness in technological and industrial applications such as UV absorption, pigment,photo-catalysis, pollution control systems and solar cells among others. Substitution of impurities into crystal lattice structure is the most commonly used method of tuning the band gap of TiO_2 for specific application and eventually leads to lattice distortion. This work utilizes the distortion in the lattice structure to estimate the band gap of doped TiO_2, for the first time, through hybridization of a particle swarm optimization algorithm(PSO) with a support vector regression(SVR) algorithm for developing a PSO-SVR model. The precision and accuracy of the developed PSO-SVR model was further justified by applying the model for estimating the effect of cobalt-sulfur co-doping, nickel-iodine co-doping, tungsten and indium doping on the band gap of TiO_2 and excellent agreement with the experimentally reported values was achieved. Practical implementation of the proposed PSO-SVR model would further widen the applications of the semiconductor and reduce the experimental stress involved in band gap determination of TiO_2.
文摘Nanosized TiO 2 particles, synthesized by microemulsion mediated method, were characterized by XRD, TEM, EDS and BET. To judge the activity of TiO 2 particles, the photocatalytic destruction of phenol in aerated suspension was studied. The result shows that the photocatalytic activity of lab made nanometer anatase TiO 2 is comparable to or higher than that of commercial titania particles. The effects of some processing parameters such as TiO 2 content, oxygen flow rate, pH value on phenol removal were also investigated. The experimental results indicate that there is an optimum value for the TiO 2 content. Sufficient O 2 supply is needed, but too high gas flow rate induces large bubbles that eliminate the gas residence time and the gas/liquid contact interface. The pH value of the phenol solutions has a complex effect on the photocatalytic activity of the particles.
基金Funded by the Science&Technology Program of Fujian Province(No.2017H0018)
文摘In the presence of titanium dioxide powder, cross-linking reaction between commercial polyvinyl alcohol(PVA)-based macromonomer and acrylic acid(AA) was initiated with potassium persulfate in an emulsifying system. As a result, PVA-AA/TiO2 composite gel particles were obtained. The morphology and composition of the particles were analyzed with scanning electron microscopy(SEM), energy scattering x-ray spectroscopy(EDS), Fourier infrared spectroscopy(FTIR), and thermogravimetric analysis(TGA). The analysis results confirmed that the particles were the expected ones. TiO2 was dispersed homogeneously within the spheroidal particles. Compared to the control gel, the composite gel particles not only contained Ti element but also showed higher thermal stability. In addition, the photo-catalytic behavior of the particles for the degradation of methyl orange contained in aqueous solution was examined. The particles exhibited photocatalytic characteristic for the degradation of the model dye, which could be modulated by simply varying the amount of cross-linking agent or TiO2. The photo-catalytic degradation percentage of methyl orange maintained at 91%-96% after using the particles three times, which indicated that TiO2 could played its role repeatedly via being fixated within polyvinyl alcohol-based gel.
文摘It was tried to prepare composite particles made of polymer and two kinds of solid powders by forming Pickeringemulsion followed by the drying-in-liquid method and to investigate how the stepwise addition of solid powders affected the contained ratio and adhesion ratio of solid powders and the structure of composite particles. Limonene oil dissolving expanded polystyrene and ethylene glycol were adopted as the dispersed phase and the continuous phase, respectively. Magnetite and titanium dioxide were used as solid powders. Magnetite was added before or after formation of the (O/W) dispersion. Titanium dioxide was added at the various elapsed times from addition of magnetite. Titanium dioxide adhered only on the surface of composite particles irrespective of addition time. At the earlier addition of both solid powders, the surface-covering type composite particles were prepared. At the latter addition of titanium dioxide, a part of magnetite adhered on the surface and the remainder was dispersed into composite particle.
文摘The effect of inhaled nano-TiO2 on lung histology and serum biochemical indexes is evaluated in healthy and adult Kunming mice（eight in each group）after exposure to TiO2 aerosols（1 500 mg/m3）in a sealed chamber.Another eight mice are exposed to indoor air to be served as a control group.Lung tissue and blood are collected after euthanizing the animals.The results show that lactate dehydrogenase（LDH）activity increases in all experimental groups.Alanine aminotransferase（ALT）activity and blood urea nitrogen（BUN）levels are increased in the group exposed to TiO2 aerosols for 28 d,and creatinine（Cr）levels are increased in 14 d and 28 d samples（P0.05）.No obvious changes are observed in other serum indexes.Lungs of mice exposed to 28 d exposure show significant but moderate increase in pulmonary inflammation,and many TiO2 particles are found in the interstitium of pulmonary alveoli.
文摘Titanium dioxide is a photocatalytically active substance used as a white pigment for cosmetics.In sunlight,titanium dioxide catalyzes decomposition of a certain amount of sebum on the skin by ultraviolet radiation.Herein,a novel white pigment for use in cosmetics was developed from titanium dioxide and phosphoric acid at pH=4 with and without glycerin,sodium lactate,lactic acid,and urea.The chemical composition,powder properties,photocatalytic activity,color phase,and smoothness of the samples were studied.Addition of glycerin led to a decline in the intensity of the X-ray diffraction(XRD)peak of TiO_(2) relative to that of the other samples.The particle size of the materials prepared with and without additives was 0.3μm;however,extensive aggregation was observed in the obtained materials.The photocatalytic activity of TiO_(2) was inhibited by phosphoric acid treatment.The materials prepared with sodium lactate,lactic acid,and glycerin exhibited higher photocatalytic activity than that prepared without additives.The obtained materials showed a high reflectance in the range of visible light,and the L^(*)values in L^(*)a^(*)b^(*) color space were high(where L^(*)defines lightness,a^(*) denotes the red/green value,and b^(*) the yellow/blue value).These results indicate that the samples prepared in this work are suitable for use as white pigments.
文摘Presence of external electrical field plays a vital role in heat transfer and fluid flow phenomena. Keeping this in view present article is a numerical investigation of stagnation point flow of water based nanoparticles suspended fluid under the influence of induced magnetic field. A detailed comparative analysis has been performed by considering Copper and Titanium dioxide nanoparticles. Utilization of similarity analysis leads to a simplified system of coupled nonlinear differential equations, which has been tackled numerically by means of shooting technique followed by Runge-Kutta of order 5. The solutions are computed correct up to 6 decimal places. Influence of pertinent parameters is examined for fluid flow, induced magnetic field, and temperature profile. One of the key findings includes that magnetic parameter plays a vital role in directing fluid flow and lowering temperature profile. Moreover, it is concluded that Cu-water based nanofluid high thermal conductivity contributes in enhancing heat transfer efficiently.
