Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized...Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.展开更多
ZnO nanoparticles with an average size of 125 nm were prepared via homogeneous precipitation method and were characterized by SEM.The products were surface-modified by the surfactant SDS.Surface-modified nano particle...ZnO nanoparticles with an average size of 125 nm were prepared via homogeneous precipitation method and were characterized by SEM.The products were surface-modified by the surfactant SDS.Surface-modified nano particles were added at a mass ratio of 1.0%,2.0%,3.0%,and 4.0%,respectively,in base oil and their friction and wear behaviors were evaluated on a MRS-10D type four-ball wear tester.After four-ball wear tests,the morphology of the rubbing surfaces was evaluated with metallographic microscope.It was revealed that the modified nano ZnO had excellent behavior for improving anti-wear property and friction coefficient,which could greatly reduce the friction of machine parts.展开更多
Uniform circinate aggregates of sheet ZnO nanoparticles with a specific surface area of 24 m^2·g^-1 were prepared by the direct precipitation method.The circinate aggregates were hexagonal ZnO,with the wall thick...Uniform circinate aggregates of sheet ZnO nanoparticles with a specific surface area of 24 m^2·g^-1 were prepared by the direct precipitation method.The circinate aggregates were hexagonal ZnO,with the wall thickness ranging from 0.5 to 1 μm and the diameter ranging from 5 to 10 μm.The backs of the circinate aggregates were regularly arranged by numerous sheet ZnO nanoparticles with a thickness of 30-80 nm and a diameter of 300-400 nm.The precursors were aggregates of sheet Zn5（CO3）2（OH）6 nanoparticles,which were decomposed into ZnO by calcining in air in the range of 200-285°C,and the ZnO retained the similar special structure.The C2H5OH content had a significant effect on the formation of sheet ZnO.The centripetal force,the Van der Waals force,and the hydrogen bond were deduced as the driving forces of the formation of circinate.展开更多
Photocatalytic degradations of p-nitrochlorbenzene (p-NCB) with distilled water wereinvestigated with ZnO crystals (catalyst) of 70nm in diameter under UV irradiation.The suitable experimental conditions are determine...Photocatalytic degradations of p-nitrochlorbenzene (p-NCB) with distilled water wereinvestigated with ZnO crystals (catalyst) of 70nm in diameter under UV irradiation.The suitable experimental conditions are determined as: ZnO 0.25g, pH 7, p-NCBconcentration 30mg/L. These variables in terms of the degradation rate have beendiscussed, which was defined as the rate of the initial degradation to the final degrada-tion of p-NCB. When all of the experimental degradation rate values are plotted as afunction of irradiation time, all of the points appeared on a single line for wide range ofp-NCB degradations. On the basis of these results, it has been concluded that at lowerZnO catalyst amount, much of the light is transmitted through the slurry in the con-tainer beaker, while at higher catalyst amount, all the incident photons are observedby the slurry. Degradation rates of p-NCB were found to decrease with increasingsolution pH. It has been concluded that the maximum degradation rate values of p-NCB under principally the same experimental conditions mentioned above are 97.4%,98.8% and 95.5% at 100min respectively. The results suggest that the photocatalyticdegradation is initiated by an oxidation of the p-NCB through ZnO surface-adsorbedhydroxyl radicals. Absorption spectra are recorded using spectrophotometer before andafter UV-irradiation in the wavelength range 200-400nm at room temperature. Itis found that the variation of irradiation time over the range 20-100min resulted inchange in the form of the spectrum linear absorption and a higher maximum valuewill be obtained at longer irradiation time.展开更多
The desulfurizer research is focused on transition-metal oxide.The paper had discussed in depth the desulfurization activity of nano-size ZnO doped with metallic elements.In order to improve the desulfurization activi...The desulfurizer research is focused on transition-metal oxide.The paper had discussed in depth the desulfurization activity of nano-size ZnO doped with metallic elements.In order to improve the desulfurization activity of nano-desulfurizer,we prepared the nano-size ZnO desulfurizer doped with iron,nickel and copper ionic respectively,using homogeneous precipitation.At the same time,the effects of different doped elements on the desulfurization activity of nano-size ZnO were compared by removing the pollutant of H2S.The experimental results showed that the desulfurization activity of metallic elements-doped nano-size ZnO increased significantly.When the molar ratio of Fe/Zn is 5:100(FZ5.0) and Cu/Zn is 2:100(CuZ2.0),their sulfur contents are 5.3% and 5.6% respectively.These desulfurizers can reach better desulfurization activity than that doped with nickel.Further research showed that,for CuZ2.0,the primary desulfurization activity is better than that of FZ5.0,but the regeneration temperature is as high as 570 ℃,and after three times regeneration/sulfuration cycle tests,the desulfurization activity decreases obviously.However,FZ5.0 can be recycled 5 times continuously at 370℃ with a stable desulfurization activity.In view of the better regeneration/sulfuration performance of FZ5.0,the dynamics of the removing H2S process by FZ5.0 were further studied.The result showed that the reaction order of removing H2S by FZ5.0 is 0.96385 at 25 ℃.展开更多
ZnO nano-particles were synthesized via an ammonical ammonium carbonate solution by precipitation method in presence of some additives such as urea, oleic and stearic acid. The morphology and crystallinity of the obta...ZnO nano-particles were synthesized via an ammonical ammonium carbonate solution by precipitation method in presence of some additives such as urea, oleic and stearic acid. The morphology and crystallinity of the obtained zinc oxide particles depend critically on the type of additive which was used. Additives also affected the crystal orientation of precipitate nano-particles. SEM, XRD, BET and UV-visible were used to characterize morphology, microstructure, specific surface area and optical properties of the products.Photo-catalysis properties of the as-prepared ZnO powders were evaluated by degradation of methyl red(acid red) in aqueous solution exposed to UV-light. Results suggested a close relationship among the morphology,size and surface area on photo-catalysis and optical properties of the particles. The widest Egvalue(3.56 e V),highest degradation and decolorization efficiency(99%) were obtained from a sample with the smallest grain size(largest surface area) which were used urea as an additive.展开更多
基金Supported by the Program of Jiangsu Development & Reform Commission(2005)the Industrial-ization Boosting Program of College Scientific Reserach Achievements of the Education Department of Jiangsu Province(JHB06-03)~~
文摘Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.
基金supported by Liaoning Provincial Office of Education for Innovation Team (Project number:2006T001)Liaoning Province of Key Laboratory Project (Project number:2008403001)
文摘ZnO nanoparticles with an average size of 125 nm were prepared via homogeneous precipitation method and were characterized by SEM.The products were surface-modified by the surfactant SDS.Surface-modified nano particles were added at a mass ratio of 1.0%,2.0%,3.0%,and 4.0%,respectively,in base oil and their friction and wear behaviors were evaluated on a MRS-10D type four-ball wear tester.After four-ball wear tests,the morphology of the rubbing surfaces was evaluated with metallographic microscope.It was revealed that the modified nano ZnO had excellent behavior for improving anti-wear property and friction coefficient,which could greatly reduce the friction of machine parts.
基金supported by the National Natural Science Foundation of China(No.50374021).
文摘Uniform circinate aggregates of sheet ZnO nanoparticles with a specific surface area of 24 m^2·g^-1 were prepared by the direct precipitation method.The circinate aggregates were hexagonal ZnO,with the wall thickness ranging from 0.5 to 1 μm and the diameter ranging from 5 to 10 μm.The backs of the circinate aggregates were regularly arranged by numerous sheet ZnO nanoparticles with a thickness of 30-80 nm and a diameter of 300-400 nm.The precursors were aggregates of sheet Zn5（CO3）2（OH）6 nanoparticles,which were decomposed into ZnO by calcining in air in the range of 200-285°C,and the ZnO retained the similar special structure.The C2H5OH content had a significant effect on the formation of sheet ZnO.The centripetal force,the Van der Waals force,and the hydrogen bond were deduced as the driving forces of the formation of circinate.
文摘Photocatalytic degradations of p-nitrochlorbenzene (p-NCB) with distilled water wereinvestigated with ZnO crystals (catalyst) of 70nm in diameter under UV irradiation.The suitable experimental conditions are determined as: ZnO 0.25g, pH 7, p-NCBconcentration 30mg/L. These variables in terms of the degradation rate have beendiscussed, which was defined as the rate of the initial degradation to the final degrada-tion of p-NCB. When all of the experimental degradation rate values are plotted as afunction of irradiation time, all of the points appeared on a single line for wide range ofp-NCB degradations. On the basis of these results, it has been concluded that at lowerZnO catalyst amount, much of the light is transmitted through the slurry in the con-tainer beaker, while at higher catalyst amount, all the incident photons are observedby the slurry. Degradation rates of p-NCB were found to decrease with increasingsolution pH. It has been concluded that the maximum degradation rate values of p-NCB under principally the same experimental conditions mentioned above are 97.4%,98.8% and 95.5% at 100min respectively. The results suggest that the photocatalyticdegradation is initiated by an oxidation of the p-NCB through ZnO surface-adsorbedhydroxyl radicals. Absorption spectra are recorded using spectrophotometer before andafter UV-irradiation in the wavelength range 200-400nm at room temperature. Itis found that the variation of irradiation time over the range 20-100min resulted inchange in the form of the spectrum linear absorption and a higher maximum valuewill be obtained at longer irradiation time.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50978073)China Postdoctoral Science Foundation (Grant No.20090450982)the Postdoctoral Research Foundation of Heilongjiang Province(Grant No.LBH-Z08171)
文摘The desulfurizer research is focused on transition-metal oxide.The paper had discussed in depth the desulfurization activity of nano-size ZnO doped with metallic elements.In order to improve the desulfurization activity of nano-desulfurizer,we prepared the nano-size ZnO desulfurizer doped with iron,nickel and copper ionic respectively,using homogeneous precipitation.At the same time,the effects of different doped elements on the desulfurization activity of nano-size ZnO were compared by removing the pollutant of H2S.The experimental results showed that the desulfurization activity of metallic elements-doped nano-size ZnO increased significantly.When the molar ratio of Fe/Zn is 5:100(FZ5.0) and Cu/Zn is 2:100(CuZ2.0),their sulfur contents are 5.3% and 5.6% respectively.These desulfurizers can reach better desulfurization activity than that doped with nickel.Further research showed that,for CuZ2.0,the primary desulfurization activity is better than that of FZ5.0,but the regeneration temperature is as high as 570 ℃,and after three times regeneration/sulfuration cycle tests,the desulfurization activity decreases obviously.However,FZ5.0 can be recycled 5 times continuously at 370℃ with a stable desulfurization activity.In view of the better regeneration/sulfuration performance of FZ5.0,the dynamics of the removing H2S process by FZ5.0 were further studied.The result showed that the reaction order of removing H2S by FZ5.0 is 0.96385 at 25 ℃.
文摘ZnO nano-particles were synthesized via an ammonical ammonium carbonate solution by precipitation method in presence of some additives such as urea, oleic and stearic acid. The morphology and crystallinity of the obtained zinc oxide particles depend critically on the type of additive which was used. Additives also affected the crystal orientation of precipitate nano-particles. SEM, XRD, BET and UV-visible were used to characterize morphology, microstructure, specific surface area and optical properties of the products.Photo-catalysis properties of the as-prepared ZnO powders were evaluated by degradation of methyl red(acid red) in aqueous solution exposed to UV-light. Results suggested a close relationship among the morphology,size and surface area on photo-catalysis and optical properties of the particles. The widest Egvalue(3.56 e V),highest degradation and decolorization efficiency(99%) were obtained from a sample with the smallest grain size(largest surface area) which were used urea as an additive.
