Ammonia （NH3） has an important use in the chemical industry and is widely found in industrial wastewater. For this investigation of copper-based rare earth composite metal materials, aqueous solutions containing 400...Ammonia （NH3） has an important use in the chemical industry and is widely found in industrial wastewater. For this investigation of copper-based rare earth composite metal materials, aqueous solutions containing 400 mg/L of ammonia were oxidized in a batch-bed reac-tor with a catalyst prepared by the co-precipitation of copper nitrate, lanthanum nitrate and cerium nitrate. Barely any of the dissolved ammo-nia was removed by wet oxidation without a catalyst, but about 88% of the ammonia was reduced during wet oxidation over the catalysts at 423 K with an oxygen partial pressure of 4.0 MPa. The catalytic redox behavior was determined by cyclic voltammetry （CV）. Furthermore, the catalysts were characterized using thermogravimetric analyzer （TGA） and scanning electron microscope-energy dispersive X-ray spectroscopy （SEM-EDX）, which showed that the catalytic behavior was related to the metal oxide properties of the catalyst. In addition, the copper-lanthanum-cerium composite-induced cytotoxicity in the human lung MRC-5 cell line was tested, and the percentage cell survival was determined by 3-（4,5-dimethylthiazol-2-yl）-5-（3-carboxymethoxyphenyl）-2-（4-sulfophenyl）-2H-tetra-zolium （MTS） analysis in vitro. No ap-parent cytotoxicity was observed when the human lung cells were exposed to the copper-lanthanum-cerium composite.展开更多
A series of three-way catalysts (TWCs),containing a small amount of precious metals (PMs,including Pt,Pd and Rh) and a large amount of promoters CeO2 and La2O3,were prepared with different precursor compounds and vari...A series of three-way catalysts (TWCs),containing a small amount of precious metals (PMs,including Pt,Pd and Rh) and a large amount of promoters CeO2 and La2O3,were prepared with different precursor compounds and various doped manners.Crystal phases,dispersion of cerium and lanthanum,textural structure and thermal stability of the catalysts were investigated by XRD,XPS and pore parameters determination.The catalytic performance was studied by the measurements of CO,C3H6 and NO conversions on dependence of temperature at stoichimetric number point (S=1.00),and from S=0.75 to 1.30 at 280℃ or 340℃ for fresh or aged samples,respectively.The correlation between the catalytic performance and the characteristics of fresh and aged samples were discussed.The results show that the sample,in which CeO2 and La2O3 are doped with mixed oxide powders,possesses poor dispersion and less thermal stability,and the conversions of NO and C3H6 are apparently lower than those of the samples aged at 850℃ The main reason is due to the lanthanum enrichment on the surface.The precious metals and cerium may be covered and enveloped,and the PMs located on the internal microporous surface where no cerium and lanthanum exist,are easier to sinter and oxidize.For the sample doped with La(NO3)3 and Ce(NO3)3 aqueous solutions,high dispersion and thermal stable CeO2 La2O3 solid solution on all the surface of microporous γ-Al2O3 is identified.The solid solution CeO2-La2O3 also possessed high dispersion in the sample doped with La2O3 powder and Ce(NO3)3 aqueous solution.The last two aged samples keep higher NO conversion at S≥1 region.展开更多
基金supported by the National Science Council of Taiwan (NSC 98-2221-E-132-003-MY3)
文摘Ammonia （NH3） has an important use in the chemical industry and is widely found in industrial wastewater. For this investigation of copper-based rare earth composite metal materials, aqueous solutions containing 400 mg/L of ammonia were oxidized in a batch-bed reac-tor with a catalyst prepared by the co-precipitation of copper nitrate, lanthanum nitrate and cerium nitrate. Barely any of the dissolved ammo-nia was removed by wet oxidation without a catalyst, but about 88% of the ammonia was reduced during wet oxidation over the catalysts at 423 K with an oxygen partial pressure of 4.0 MPa. The catalytic redox behavior was determined by cyclic voltammetry （CV）. Furthermore, the catalysts were characterized using thermogravimetric analyzer （TGA） and scanning electron microscope-energy dispersive X-ray spectroscopy （SEM-EDX）, which showed that the catalytic behavior was related to the metal oxide properties of the catalyst. In addition, the copper-lanthanum-cerium composite-induced cytotoxicity in the human lung MRC-5 cell line was tested, and the percentage cell survival was determined by 3-（4,5-dimethylthiazol-2-yl）-5-（3-carboxymethoxyphenyl）-2-（4-sulfophenyl）-2H-tetra-zolium （MTS） analysis in vitro. No ap-parent cytotoxicity was observed when the human lung cells were exposed to the copper-lanthanum-cerium composite.
基金Project (No. 9712301) supported by Ford-China Research and Development Fund
文摘A series of three-way catalysts (TWCs),containing a small amount of precious metals (PMs,including Pt,Pd and Rh) and a large amount of promoters CeO2 and La2O3,were prepared with different precursor compounds and various doped manners.Crystal phases,dispersion of cerium and lanthanum,textural structure and thermal stability of the catalysts were investigated by XRD,XPS and pore parameters determination.The catalytic performance was studied by the measurements of CO,C3H6 and NO conversions on dependence of temperature at stoichimetric number point (S=1.00),and from S=0.75 to 1.30 at 280℃ or 340℃ for fresh or aged samples,respectively.The correlation between the catalytic performance and the characteristics of fresh and aged samples were discussed.The results show that the sample,in which CeO2 and La2O3 are doped with mixed oxide powders,possesses poor dispersion and less thermal stability,and the conversions of NO and C3H6 are apparently lower than those of the samples aged at 850℃ The main reason is due to the lanthanum enrichment on the surface.The precious metals and cerium may be covered and enveloped,and the PMs located on the internal microporous surface where no cerium and lanthanum exist,are easier to sinter and oxidize.For the sample doped with La(NO3)3 and Ce(NO3)3 aqueous solutions,high dispersion and thermal stable CeO2 La2O3 solid solution on all the surface of microporous γ-Al2O3 is identified.The solid solution CeO2-La2O3 also possessed high dispersion in the sample doped with La2O3 powder and Ce(NO3)3 aqueous solution.The last two aged samples keep higher NO conversion at S≥1 region.
基金National Natural Science Foundation of China(21276036)Liaoning Provincial Nature Science Foundation of China(2014025018)the Fundamental Research Funds for the Central Universities(3132014323)
