According to the design principle of the central composite experimental,the method of response surface analysis with three factors and three levels was adopted based on one factor test.A second-order quadratic equatio...According to the design principle of the central composite experimental,the method of response surface analysis with three factors and three levels was adopted based on one factor test.A second-order quadratic equation for photocatalysis of Procion Red MX-5B was built.Response surface and contour were graphed with the decoloration rate of Procion Red MX-5B as the response value.Based on the analysis of the response surface plots and their corresponding contour plots,effects of pH value,irradiation time and catalyst loading were explored.By using this new method,the optimum decoloration condition was obtained as follows:pH value,1.3;irradiation time,49.9 min;catalyst loading,0.57 g/L.In the optimization,R-Squared and Adj R-Squared correlation coefficients for quadratic model were evaluated quite satisfactorily as 0.9310 and 0.8620,respectively.Under the optimum conditions established,the performance of 99.47% for color removal was experimentally reached.It was found that all factors considered have an important effect on the decolorization efficiency of Procion Red MX-5B.By the ANOVA analysis and model confirmation the optimal solution obtained using RSM was experimentally validated and credible with preferable instructional ability for experiments.展开更多
A series of TiO 2-XSiO 2[X denotes the molar fraction(%) of silica in the mixed oxides] with different \{n(Ti)\}(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared were ch...A series of TiO 2-XSiO 2[X denotes the molar fraction(%) of silica in the mixed oxides] with different \{n(Ti)\}(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared were characterized by XRD, thermal analysis, FTIR, UV-Vis and SPS. The characterization results of FTIR and UV-Vis spectra show that Ti atoms were gradually changed from octahedral coordination to tetrahedral coordination with the addition of silica, which is not beneficial for obtaining strong Brnsted acidity and higher photocatalytic activity. The photocatalytic activity experiments, which were conducted by using heptane(or SO 2) as the model reactant, showed that TiO 2-SiO 2 containing a suitable amount of silica can exhibit much higher photocatalytic activity than pure TiO 2. The enhanced photocatalytic activity can be attributed to three following factors: (1) smaller crystalline size; (2) higher thermal stability; (3) the new strong Brnsted acidity.展开更多
A series of catalysts were prepared by doping different loadings of CeO2 over TiO2-SiO2-WO3 and used for the selective catalytic reduction of NOx by NH3. The experimental results showed that the selective catalytic re...A series of catalysts were prepared by doping different loadings of CeO2 over TiO2-SiO2-WO3 and used for the selective catalytic reduction of NOx by NH3. The experimental results showed that the selective catalytic reduction(SCR) performance and SO2-resistant ability of TiO2-SiO2-WO3 were greatly enhanced by the introduction of cerium. The catalyst containing 10% CeO2 showed the highest NO conversion in a wide temperature range and good N2 selectivity with broad operation temperature window at the gas hourly space velocity(GHSV) of 30000 h–1, which was a very promising catalyst for NOx abatement from diesel engine exhaust. The catalysts were characterized by X-ray diffraction(XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy(SEM-EDS), N2 adsorption-desorption(BET) and X-ray photoelectron spectroscopy(XPS). The characterization results showed that the bigger pore radius, higher surface atomic concentration and dispersion of Ce and the abundant adsorbed oxygen on the surface of catalyst contributed to the best NH3-SCR performance of CeO2/TiO2-SiO2-WO3 catalyst containing 10% CeO2.展开更多
Using glucose and sucrose as the electron donors,the photocatalytic hydrogen evolution over Pt/TiO2 was investigated.Glucose and sucrose enhance notably the activity for hydrogen generation.The amounts of produced H2 ...Using glucose and sucrose as the electron donors,the photocatalytic hydrogen evolution over Pt/TiO2 was investigated.Glucose and sucrose enhance notably the activity for hydrogen generation.The amounts of produced H2 increase almost proportionally to time within 5 h irradiation in the reaction systems of the two electron donors.The effect of the initial concentration of glucose and sucrose on the reaction rate is consistent with the Langmuir-Hinshelwood kinetic model.After 5 h irradiation,the COD(chemical oxygen demand) in the reaction system of glucose and in that of sucrose decrease by 33.2%,11.4% respectively.The effect of electron donors on the flat-band potential of conduction band of TiO2 electrode was investigated.The flat-band potential of conduction band of TiO2 electrode in the presence of the electron donors shifts negatively,and the shift in the presence of glucose is larger than that in the presence of sucrose due to glucose having a larger adsorption amount on TiO2.展开更多
A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acid...A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.展开更多
本文利用纳米TiO2粉体,以聚乙烯吡咯烷(PVP)为分散剂和结构引导剂,以正硅酸乙酯(TEOS)为纳米SiO2前驱体,在纳米TiO2粉体表面包覆纳米SiO2,制备纳米TiO2-SiO2复合粒子。将纳米TiO2-SiO2复合粒子整理到棉织物上,并通过十六烷基三甲氧...本文利用纳米TiO2粉体,以聚乙烯吡咯烷(PVP)为分散剂和结构引导剂,以正硅酸乙酯(TEOS)为纳米SiO2前驱体,在纳米TiO2粉体表面包覆纳米SiO2,制备纳米TiO2-SiO2复合粒子。将纳米TiO2-SiO2复合粒子整理到棉织物上,并通过十六烷基三甲氧基硅烷(HDTMS)低表面能修饰后,得到抗紫外和超疏水复合功能棉织物。探究制备纳米TiO2-SiO2复合粒子的最佳工艺,并对复合粒子和处理后棉织物进行表征。结果表明,当PVP用量为0.025%,硅钛比例为2∶1,氨水用量为5 m L时,纳米SiO2包覆TiO2效果较好。处理棉织物的抗紫外指数(UPF)达115.42,紫外线UVA(320420 nm)透过率为3.35%,接触角为156.54°,滚动角为8°,具有优异的抗紫外、超疏水性能。此外,处理棉织物经过24 h紫外线照射后,接触角仍为152.73°,滚动角仍可达到9°,实现了耐紫外线稳定性。展开更多
基金Sponsored by the National Natural Science Foundation of China (Grant No. 51078100)the National Creative Research Groups granted by NSFC(Grant No. 50821002)+1 种基金Excellent Youth Foundation of Heilongjiang Scientific Committee(Grant No. JC2010-03)State Key Laboratory of Urban Water Resource and Environment(Grant No. 2010DX11)
摘要According to the design principle of the central composite experimental,the method of response surface analysis with three factors and three levels was adopted based on one factor test.A second-order quadratic equation for photocatalysis of Procion Red MX-5B was built.Response surface and contour were graphed with the decoloration rate of Procion Red MX-5B as the response value.Based on the analysis of the response surface plots and their corresponding contour plots,effects of pH value,irradiation time and catalyst loading were explored.By using this new method,the optimum decoloration condition was obtained as follows:pH value,1.3;irradiation time,49.9 min;catalyst loading,0.57 g/L.In the optimization,R-Squared and Adj R-Squared correlation coefficients for quadratic model were evaluated quite satisfactorily as 0.9310 and 0.8620,respectively.Under the optimum conditions established,the performance of 99.47% for color removal was experimentally reached.It was found that all factors considered have an important effect on the decolorization efficiency of Procion Red MX-5B.By the ANOVA analysis and model confirmation the optimal solution obtained using RSM was experimentally validated and credible with preferable instructional ability for experiments.
基金Supported by the National Natural Science Foundation of China(No.2 0 2 770 15 )
摘要A series of TiO 2-XSiO 2[X denotes the molar fraction(%) of silica in the mixed oxides] with different \{n(Ti)\}(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared were characterized by XRD, thermal analysis, FTIR, UV-Vis and SPS. The characterization results of FTIR and UV-Vis spectra show that Ti atoms were gradually changed from octahedral coordination to tetrahedral coordination with the addition of silica, which is not beneficial for obtaining strong Brnsted acidity and higher photocatalytic activity. The photocatalytic activity experiments, which were conducted by using heptane(or SO 2) as the model reactant, showed that TiO 2-SiO 2 containing a suitable amount of silica can exhibit much higher photocatalytic activity than pure TiO 2. The enhanced photocatalytic activity can be attributed to three following factors: (1) smaller crystalline size; (2) higher thermal stability; (3) the new strong Brnsted acidity.
基金supported by the National Natural Science Foundation of China(21173153)the National High Technology Research and Development Program of China(863 project)(2013AA065304)
摘要A series of catalysts were prepared by doping different loadings of CeO2 over TiO2-SiO2-WO3 and used for the selective catalytic reduction of NOx by NH3. The experimental results showed that the selective catalytic reduction(SCR) performance and SO2-resistant ability of TiO2-SiO2-WO3 were greatly enhanced by the introduction of cerium. The catalyst containing 10% CeO2 showed the highest NO conversion in a wide temperature range and good N2 selectivity with broad operation temperature window at the gas hourly space velocity(GHSV) of 30000 h–1, which was a very promising catalyst for NOx abatement from diesel engine exhaust. The catalysts were characterized by X-ray diffraction(XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy(SEM-EDS), N2 adsorption-desorption(BET) and X-ray photoelectron spectroscopy(XPS). The characterization results showed that the bigger pore radius, higher surface atomic concentration and dispersion of Ce and the abundant adsorbed oxygen on the surface of catalyst contributed to the best NH3-SCR performance of CeO2/TiO2-SiO2-WO3 catalyst containing 10% CeO2.
摘要Using glucose and sucrose as the electron donors,the photocatalytic hydrogen evolution over Pt/TiO2 was investigated.Glucose and sucrose enhance notably the activity for hydrogen generation.The amounts of produced H2 increase almost proportionally to time within 5 h irradiation in the reaction systems of the two electron donors.The effect of the initial concentration of glucose and sucrose on the reaction rate is consistent with the Langmuir-Hinshelwood kinetic model.After 5 h irradiation,the COD(chemical oxygen demand) in the reaction system of glucose and in that of sucrose decrease by 33.2%,11.4% respectively.The effect of electron donors on the flat-band potential of conduction band of TiO2 electrode was investigated.The flat-band potential of conduction band of TiO2 electrode in the presence of the electron donors shifts negatively,and the shift in the presence of glucose is larger than that in the presence of sucrose due to glucose having a larger adsorption amount on TiO2.
摘要A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.
摘要本文利用纳米TiO2粉体,以聚乙烯吡咯烷(PVP)为分散剂和结构引导剂,以正硅酸乙酯(TEOS)为纳米SiO2前驱体,在纳米TiO2粉体表面包覆纳米SiO2,制备纳米TiO2-SiO2复合粒子。将纳米TiO2-SiO2复合粒子整理到棉织物上,并通过十六烷基三甲氧基硅烷(HDTMS)低表面能修饰后,得到抗紫外和超疏水复合功能棉织物。探究制备纳米TiO2-SiO2复合粒子的最佳工艺,并对复合粒子和处理后棉织物进行表征。结果表明,当PVP用量为0.025%,硅钛比例为2∶1,氨水用量为5 m L时,纳米SiO2包覆TiO2效果较好。处理棉织物的抗紫外指数(UPF)达115.42,紫外线UVA(320420 nm)透过率为3.35%,接触角为156.54°,滚动角为8°,具有优异的抗紫外、超疏水性能。此外,处理棉织物经过24 h紫外线照射后,接触角仍为152.73°,滚动角仍可达到9°,实现了耐紫外线稳定性。