The Kevlar/polytetrafluroethylene(Kevlar/PTFE) fabric composite can be used as a self-lubricating liner of the self-lubricating bearing.Many types of nano-particles can improve the tribological performance of the po...The Kevlar/polytetrafluroethylene(Kevlar/PTFE) fabric composite can be used as a self-lubricating liner of the self-lubricating bearing.Many types of nano-particles can improve the tribological performance of the polymer-based composite.Unfortunately,up to now,published work on the effect of nano-particles on the tribological performance of the fabric composite which can be used as a self-lubricating liner is quite scarce.Therefore,for the purpose of exploring a way to significantly improve the tribological performance of the fabric composite,the tribological performance of the Kevlar/PTFE fabric composite filled with nano-titania is evaluated by using the block-on-ring wear tester.The scanning electron microscopy is utilized to observe the morphologies of worn surfaces of the fabric composites and the counterparts.The tensile properties of the composites are evaluated on the universal material testing machine.The test results show that the addition of nano-titania at a proper mass fraction of the matrix resin improves the wear resistance and the tensile strength,decreases the friction coefficient,and makes the wear volume of the composite reach a relative steady state more quickly;plastic deformation and microcutting are important for the wear of the fabric composite;a lubricating layer is formed on the worn surface of the composite during sliding,and the lubricating layer is critical for the tribological performance of the composite;the formation and properties of the lubricating layer are influenced by the nano-titania particles.The proposed study on the effect of nano-titania on the tribological performance of the Kevlar/PTFE fabric composite,especially on the evolution of the worn surface of the composite,provides the basis for further understanding of the influence mechanism of the nano-particles on the tribological performance of the composite and explores a method of improving the tribological performance of the composite.展开更多
In this study, a new technique of air cleaning by plasma combined with catalyst was proposed, which consisted of electrostatic precipitation, volatile organic compounds (VOCs) decomposition and sterilization. A nove...In this study, a new technique of air cleaning by plasma combined with catalyst was proposed, which consisted of electrostatic precipitation, volatile organic compounds (VOCs) decomposition and sterilization. A novel indoor air purifier based on this technique was adopted. The experimental results showed that formaldehyde decomposition by the plasma-catalyst hybrid system was more efficient than that by plasma only, Positive discharge was better than negative discharge in formaldehyde removal. Meanwhile, the outlet concentration of ozone byproduct was effectively reduced by the nano-titania catalyst.展开更多
The highly pure nano-crystal Mg,Al-hydrotalcite with titania doping was synthesized by one-step liquid reaction method at atmospheric pressure. The preparation of the Mg,Al-hydrotalcite nano-crystal after doping titan...The highly pure nano-crystal Mg,Al-hydrotalcite with titania doping was synthesized by one-step liquid reaction method at atmospheric pressure. The preparation of the Mg,Al-hydrotalcite nano-crystal after doping titania was investigated according to the results of XRD, TEM, IR and DSC. Moreover, based on the DSC test results, the thermal mechanism functions of the Mg,Al-hydrotalcite with titania doping were studied after calculation and comparison.展开更多
PEG (Polyethylene Glycol)-grafted nano-titania has been obtained in a one-step procedure using hexamethylene diisocyanate as the coupling agent and dibutyltin dilaurate as the catalyst in toluene at 80℃ and charact...PEG (Polyethylene Glycol)-grafted nano-titania has been obtained in a one-step procedure using hexamethylene diisocyanate as the coupling agent and dibutyltin dilaurate as the catalyst in toluene at 80℃ and characterized qualitatively by FTIR and quantitatively by elemental analysis and thermogravimetric analysis. A comparison of nano-titania with two other commonly used inorganic nanoparticles, nano-silica and nano-alumina, is made, revealing that reactivity order is nano- silica 〉 nano-alumina 〉 nano-titania in view of PEG grafting. Possible mechanism of PEG grafting is also discussed.展开更多
<span style="font-family:Verdana;"><span style="font-family:Verdana;">Environmental sustainability apart from spoken at different levels need</span></span><span style=&qu...<span style="font-family:Verdana;"><span style="font-family:Verdana;">Environmental sustainability apart from spoken at different levels need</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> to </span><span style="font-family:Verdana;">investigate the management of industrial activities in terms of</span><span style="font-family:Verdana;"> eco</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">friendliness. It is well known that effluents from various industries become a major source of environmental degradation in particular water pollution. Thus water analysis report turns to be more significant, to determine the quality and standard of life maintained in a typical ecosystem. This study includes the analysis of physico-chemical factors of raw as well as treated water samples from Korattur Lake employing nano sized adsorbents like titania with tuned structural and morphological properties through organic plant extract. The XRD analysis, BET analysis, DRS-UV analysis, SEM and TEM analysis have been carried out and reported. The marked influence of leaf extract as a template is reflected in reduced crystallite size (12.4 nm) with maximum surface area 105 m</span><b><span style="font-family:Verdana;"><sup></sup></span></b><span style="font-family:Verdana;"></span><sup><span style="font-family:Verdana;">2</span><b><span style="font-family:Verdana;"></span></b></sup></span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">/g along with bathochromic shift of absorption edge. The usual indicators of contamination level at a given source namely Biological Oxygen Demand (BOD-85%), Chemical Oxygen Demand (COD-94.5%), Dissolved Oxygen (88%), Total Suspended Solids (TSS-75.6%), Electrical Conductivity (74.5%), Chloride (89%), Nitrate and Phosphate contents etc. were used to ascertain the efficiency of contaminants removal using tea leaf extract mediated nano titania. The reliability factor of the treatment process was found to be less than 1, revealed the effectiveness and reliability of nano material.</span></span></span>展开更多
In order to study the structure transition during calcination, nano-titania powders prepared by hydrolyzing precipitation approach and calcined at 300, 400, 500, 600 and 700 ℃ were characterized by XRD, TEM and elect...In order to study the structure transition during calcination, nano-titania powders prepared by hydrolyzing precipitation approach and calcined at 300, 400, 500, 600 and 700 ℃ were characterized by XRD, TEM and electron diffraction(ED), respectively. The results show that titania powders calcined below 500 ℃ are almost composed of anatase, rutile appears below 500 ℃ and its ratio increases gradually with increase of calcin temperature; nano-titania particles are smaller than 40 nm mostly and the dispersion is related to calcining temperature; the inter-planar distances of nano-anatase single crystalline change gradually when calcing temperature increases to 500 ℃; so do that of nano-rutile single crystalline when calcining temperature charges from 600 to 700 ℃. The conclusions can be drawn that the temperature of transformation from anatase to rutile is below 500 ℃ and the process carries on gradually. Both inter-planar distances and the structure of nano-titania transform gradually with increasing calcing temperature.展开更多
A low temperature preparation of nano TiO2 using sol-gel method was proposed. The antibacterial properties of the treatment solution and the treated cotton fabrics obtained via a dip-padding process were evaluated. XR...A low temperature preparation of nano TiO2 using sol-gel method was proposed. The antibacterial properties of the treatment solution and the treated cotton fabrics obtained via a dip-padding process were evaluated. XRD pattern shows that the nano TiO2 produced is an anatase phase. Aqueous nano-dispersion of the nano TiO2 exhibites positive results as an antibacterial finishing agent for cotton fabrics. The treatment solution possesses antibacterial rates of over 92% and 88.9% against Escherichia coli and Bacillus subtilis,respectively. The treated fabrics are slightly downgraded but still maintained over 89% and 83% of reduction towards the same bacteria. After washing for 50 times,the antibacterial performances of the treated fabric still remains at a relatively high level,indicating the durable characteristic of nano TiO2 treatment.展开更多
In order to study the effect mechanism of N-doping on the visible-light photoactivity of TiO2,N-doped and un-doped TiO2 nano-powders were prepared by an acid-catalyzed sol-gel method and characterized by X-ray diffrac...In order to study the effect mechanism of N-doping on the visible-light photoactivity of TiO2,N-doped and un-doped TiO2 nano-powders were prepared by an acid-catalyzed sol-gel method and characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),electron spin resonance(ESR),UV-Vis diffuse reflection spectra(DRS),and photoluminescence spectra(PL)techniques.Their photoactivities are evaluated by the photocatalytic degradation of methylene blue(MB)in aqueous solution under UV light and visible-light irradiation,respectively.The results reveal that the as-prepared N-doped sample with single anatase exhibits a good visible-light photoactivity,whereas its UV photoactivity decreases slightly,compared with the un-doped sample.The N-doping increases surface hydroxyl groups and forms abundant oxygen vacancies bounding single electrons.The visible-light response of the N-doped sample can be ascribed to a synergetic effect of impurity energy levels due to the substitutional N-doping and defect energy levels owing to the formation of oxygen vacancies.The separation of the photo-generated electron and hole can be promoted by the increase in both oxygen vacancies and surface hydroxyl groups,which are conducive for enhancement of photoactivity.The increase in visible-light photoactivity of the N-doped sample is related with the decrease in its PL spectral intensity in visible-light region.展开更多
Titania coating of multi wall carbon nano tube(MWCNT) was carried out by sol-gel method in order to improve its photo catalytic properties.The effect of MWCNT/TiO_2 mass to volume ratio on adsorption ability,reaction ...Titania coating of multi wall carbon nano tube(MWCNT) was carried out by sol-gel method in order to improve its photo catalytic properties.The effect of MWCNT/TiO_2 mass to volume ratio on adsorption ability,reaction rate and photo-catalytic removal efficiency of dibenzothiophene(DBT) from n-hexane solution was investigated using a 9 W UV lamp.The results show that the addition of nanotubes improves the photo-catalytic properties of TiO_2 by two factors;however,the DBT removal rate versus MWCNT content is found to follow a bimodal pattern.Two factors are observed to affect the removal rate of DBT and produce two optimum values for MWCNT content.First,large quantities of MWCNTs prevent light absorption by the solution and decrease removal efficiency.By contrast,a low dosage of MWCNT causes recombination of the electron holes,which also decreases the DBT removal rate.The optimum MWCNT contents in the composite are found to be 0.25 g and 0.75 g MWCNT per 80 m L of sol.展开更多
Titania nano particles were synthesized at carbon paste electrode by cyclic voltammetry and then it was employed for the determination of acetaminophen in phosphate buffer at pH 7.4. Carbon paste electrode with titani...Titania nano particles were synthesized at carbon paste electrode by cyclic voltammetry and then it was employed for the determination of acetaminophen in phosphate buffer at pH 7.4. Carbon paste electrode with titania nano particle displayed excellent electrochemically catalytic activities by shifting the oxidation potential of acetaminophen towards the negative side. The mass transfer process at electrochemical interface was diffusion controlled. Electrochemical techniques such as, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods were used to measure the resistance of the electrodes. The resistance of the titanium electrode decreased in two orders when compared to the bare carbon paste electrode;the decrease in the resistance of the electrode and increase in the surface area of the electrode are responsible for the negative shifting of the oxidation potential of acetaminophen. The present method was applied to the determination of actetaminophen in paracetamol tablet, urine and blood sample by using standard addition method and the obtained results were satisfactory with a good recovery of 98%.展开更多
Yb 3+-doped TiO_2 composite nano-particles were prepared by the acid-catalyzed sol-gel method using Ti(OC_4H_9)_4 and Yb(NO_3)_3 as precursors. The effects of the amount of Yb 3+ doping and calcination temperature on ...Yb 3+-doped TiO_2 composite nano-particles were prepared by the acid-catalyzed sol-gel method using Ti(OC_4H_9)_4 and Yb(NO_3)_3 as precursors. The effects of the amount of Yb 3+ doping and calcination temperature on the phase transformation, crystallite size, surface texture of the nanopowders were investigated by XRD and BET specific surface area. Their photocatalytic activities were evaluated using the photocatalytic degradation of methylene blue in aqueous solution as a probe reaction. At the interface, titanium ions substitute for ytterbium ions in the lattice of Yb_2O_3 to form Ti-O-Yb bonds, which cause distortion and inhibit the anatase to rutile phase transformation in TiO_2. The results indicate that Yb 3+-doping can enhance the photocatalytic activity of TiO_2 nano-powders as compared with pure TiO_2. 0.125%(mass fraction) Yb 3+ doped TiO_2 nano-powders calcined at 600 ℃ for 2 h show the highest photocatalytic activity. The increase in photoactivity is due to the effects of the factors such as crystal phase, crystallite size, surface chemical property, surface density of OH groups, and surface texture properties of the TiO_2 nano-powders.展开更多
文摘The Kevlar/polytetrafluroethylene(Kevlar/PTFE) fabric composite can be used as a self-lubricating liner of the self-lubricating bearing.Many types of nano-particles can improve the tribological performance of the polymer-based composite.Unfortunately,up to now,published work on the effect of nano-particles on the tribological performance of the fabric composite which can be used as a self-lubricating liner is quite scarce.Therefore,for the purpose of exploring a way to significantly improve the tribological performance of the fabric composite,the tribological performance of the Kevlar/PTFE fabric composite filled with nano-titania is evaluated by using the block-on-ring wear tester.The scanning electron microscopy is utilized to observe the morphologies of worn surfaces of the fabric composites and the counterparts.The tensile properties of the composites are evaluated on the universal material testing machine.The test results show that the addition of nano-titania at a proper mass fraction of the matrix resin improves the wear resistance and the tensile strength,decreases the friction coefficient,and makes the wear volume of the composite reach a relative steady state more quickly;plastic deformation and microcutting are important for the wear of the fabric composite;a lubricating layer is formed on the worn surface of the composite during sliding,and the lubricating layer is critical for the tribological performance of the composite;the formation and properties of the lubricating layer are influenced by the nano-titania particles.The proposed study on the effect of nano-titania on the tribological performance of the Kevlar/PTFE fabric composite,especially on the evolution of the worn surface of the composite,provides the basis for further understanding of the influence mechanism of the nano-particles on the tribological performance of the composite and explores a method of improving the tribological performance of the composite.
基金National Natural Science Foundation of China(No.50436040)
文摘In this study, a new technique of air cleaning by plasma combined with catalyst was proposed, which consisted of electrostatic precipitation, volatile organic compounds (VOCs) decomposition and sterilization. A novel indoor air purifier based on this technique was adopted. The experimental results showed that formaldehyde decomposition by the plasma-catalyst hybrid system was more efficient than that by plasma only, Positive discharge was better than negative discharge in formaldehyde removal. Meanwhile, the outlet concentration of ozone byproduct was effectively reduced by the nano-titania catalyst.
基金Project (2004E113) Supported by Natural Science Basic Research Plan of Shaanxi Province of China
文摘The highly pure nano-crystal Mg,Al-hydrotalcite with titania doping was synthesized by one-step liquid reaction method at atmospheric pressure. The preparation of the Mg,Al-hydrotalcite nano-crystal after doping titania was investigated according to the results of XRD, TEM, IR and DSC. Moreover, based on the DSC test results, the thermal mechanism functions of the Mg,Al-hydrotalcite with titania doping were studied after calculation and comparison.
文摘PEG (Polyethylene Glycol)-grafted nano-titania has been obtained in a one-step procedure using hexamethylene diisocyanate as the coupling agent and dibutyltin dilaurate as the catalyst in toluene at 80℃ and characterized qualitatively by FTIR and quantitatively by elemental analysis and thermogravimetric analysis. A comparison of nano-titania with two other commonly used inorganic nanoparticles, nano-silica and nano-alumina, is made, revealing that reactivity order is nano- silica 〉 nano-alumina 〉 nano-titania in view of PEG grafting. Possible mechanism of PEG grafting is also discussed.
文摘<span style="font-family:Verdana;"><span style="font-family:Verdana;">Environmental sustainability apart from spoken at different levels need</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> to </span><span style="font-family:Verdana;">investigate the management of industrial activities in terms of</span><span style="font-family:Verdana;"> eco</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">friendliness. It is well known that effluents from various industries become a major source of environmental degradation in particular water pollution. Thus water analysis report turns to be more significant, to determine the quality and standard of life maintained in a typical ecosystem. This study includes the analysis of physico-chemical factors of raw as well as treated water samples from Korattur Lake employing nano sized adsorbents like titania with tuned structural and morphological properties through organic plant extract. The XRD analysis, BET analysis, DRS-UV analysis, SEM and TEM analysis have been carried out and reported. The marked influence of leaf extract as a template is reflected in reduced crystallite size (12.4 nm) with maximum surface area 105 m</span><b><span style="font-family:Verdana;"><sup></sup></span></b><span style="font-family:Verdana;"></span><sup><span style="font-family:Verdana;">2</span><b><span style="font-family:Verdana;"></span></b></sup></span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">/g along with bathochromic shift of absorption edge. The usual indicators of contamination level at a given source namely Biological Oxygen Demand (BOD-85%), Chemical Oxygen Demand (COD-94.5%), Dissolved Oxygen (88%), Total Suspended Solids (TSS-75.6%), Electrical Conductivity (74.5%), Chloride (89%), Nitrate and Phosphate contents etc. were used to ascertain the efficiency of contaminants removal using tea leaf extract mediated nano titania. The reliability factor of the treatment process was found to be less than 1, revealed the effectiveness and reliability of nano material.</span></span></span>
文摘In order to study the structure transition during calcination, nano-titania powders prepared by hydrolyzing precipitation approach and calcined at 300, 400, 500, 600 and 700 ℃ were characterized by XRD, TEM and electron diffraction(ED), respectively. The results show that titania powders calcined below 500 ℃ are almost composed of anatase, rutile appears below 500 ℃ and its ratio increases gradually with increase of calcin temperature; nano-titania particles are smaller than 40 nm mostly and the dispersion is related to calcining temperature; the inter-planar distances of nano-anatase single crystalline change gradually when calcing temperature increases to 500 ℃; so do that of nano-rutile single crystalline when calcining temperature charges from 600 to 700 ℃. The conclusions can be drawn that the temperature of transformation from anatase to rutile is below 500 ℃ and the process carries on gradually. Both inter-planar distances and the structure of nano-titania transform gradually with increasing calcing temperature.
基金Project (06YFJMJC02700) supported by Municipal Natural Science Foundation of Tianjin, China
文摘A low temperature preparation of nano TiO2 using sol-gel method was proposed. The antibacterial properties of the treatment solution and the treated cotton fabrics obtained via a dip-padding process were evaluated. XRD pattern shows that the nano TiO2 produced is an anatase phase. Aqueous nano-dispersion of the nano TiO2 exhibites positive results as an antibacterial finishing agent for cotton fabrics. The treatment solution possesses antibacterial rates of over 92% and 88.9% against Escherichia coli and Bacillus subtilis,respectively. The treated fabrics are slightly downgraded but still maintained over 89% and 83% of reduction towards the same bacteria. After washing for 50 times,the antibacterial performances of the treated fabric still remains at a relatively high level,indicating the durable characteristic of nano TiO2 treatment.
基金Research Foundation for Young Academic Core of Harbin Normal University,China(No.08XBSK89)Science and Technology Research Program of Education Bureau of Heilongjiang Province of China(No.11551115)
文摘In order to study the effect mechanism of N-doping on the visible-light photoactivity of TiO2,N-doped and un-doped TiO2 nano-powders were prepared by an acid-catalyzed sol-gel method and characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),electron spin resonance(ESR),UV-Vis diffuse reflection spectra(DRS),and photoluminescence spectra(PL)techniques.Their photoactivities are evaluated by the photocatalytic degradation of methylene blue(MB)in aqueous solution under UV light and visible-light irradiation,respectively.The results reveal that the as-prepared N-doped sample with single anatase exhibits a good visible-light photoactivity,whereas its UV photoactivity decreases slightly,compared with the un-doped sample.The N-doping increases surface hydroxyl groups and forms abundant oxygen vacancies bounding single electrons.The visible-light response of the N-doped sample can be ascribed to a synergetic effect of impurity energy levels due to the substitutional N-doping and defect energy levels owing to the formation of oxygen vacancies.The separation of the photo-generated electron and hole can be promoted by the increase in both oxygen vacancies and surface hydroxyl groups,which are conducive for enhancement of photoactivity.The increase in visible-light photoactivity of the N-doped sample is related with the decrease in its PL spectral intensity in visible-light region.
文摘Titania coating of multi wall carbon nano tube(MWCNT) was carried out by sol-gel method in order to improve its photo catalytic properties.The effect of MWCNT/TiO_2 mass to volume ratio on adsorption ability,reaction rate and photo-catalytic removal efficiency of dibenzothiophene(DBT) from n-hexane solution was investigated using a 9 W UV lamp.The results show that the addition of nanotubes improves the photo-catalytic properties of TiO_2 by two factors;however,the DBT removal rate versus MWCNT content is found to follow a bimodal pattern.Two factors are observed to affect the removal rate of DBT and produce two optimum values for MWCNT content.First,large quantities of MWCNTs prevent light absorption by the solution and decrease removal efficiency.By contrast,a low dosage of MWCNT causes recombination of the electron holes,which also decreases the DBT removal rate.The optimum MWCNT contents in the composite are found to be 0.25 g and 0.75 g MWCNT per 80 m L of sol.
文摘Titania nano particles were synthesized at carbon paste electrode by cyclic voltammetry and then it was employed for the determination of acetaminophen in phosphate buffer at pH 7.4. Carbon paste electrode with titania nano particle displayed excellent electrochemically catalytic activities by shifting the oxidation potential of acetaminophen towards the negative side. The mass transfer process at electrochemical interface was diffusion controlled. Electrochemical techniques such as, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods were used to measure the resistance of the electrodes. The resistance of the titanium electrode decreased in two orders when compared to the bare carbon paste electrode;the decrease in the resistance of the electrode and increase in the surface area of the electrode are responsible for the negative shifting of the oxidation potential of acetaminophen. The present method was applied to the determination of actetaminophen in paracetamol tablet, urine and blood sample by using standard addition method and the obtained results were satisfactory with a good recovery of 98%.
文摘Yb 3+-doped TiO_2 composite nano-particles were prepared by the acid-catalyzed sol-gel method using Ti(OC_4H_9)_4 and Yb(NO_3)_3 as precursors. The effects of the amount of Yb 3+ doping and calcination temperature on the phase transformation, crystallite size, surface texture of the nanopowders were investigated by XRD and BET specific surface area. Their photocatalytic activities were evaluated using the photocatalytic degradation of methylene blue in aqueous solution as a probe reaction. At the interface, titanium ions substitute for ytterbium ions in the lattice of Yb_2O_3 to form Ti-O-Yb bonds, which cause distortion and inhibit the anatase to rutile phase transformation in TiO_2. The results indicate that Yb 3+-doping can enhance the photocatalytic activity of TiO_2 nano-powders as compared with pure TiO_2. 0.125%(mass fraction) Yb 3+ doped TiO_2 nano-powders calcined at 600 ℃ for 2 h show the highest photocatalytic activity. The increase in photoactivity is due to the effects of the factors such as crystal phase, crystallite size, surface chemical property, surface density of OH groups, and surface texture properties of the TiO_2 nano-powders.