In the present work, a novel heterogeneous photo-Fenton catalyst was prepared by iron and cerium pillared bentonite. The catalyst Fe-Ce/bentonite was characterized by X-ray diffraction （XRD）, X-ray fluorescence （XR...In the present work, a novel heterogeneous photo-Fenton catalyst was prepared by iron and cerium pillared bentonite. The catalyst Fe-Ce/bentonite was characterized by X-ray diffraction （XRD）, X-ray fluorescence （XRF）, Brunauer-Emmett-Teller （BET） and scanning electron microscopy （SEM） methods. It is found that Fe and Ce intercalate into the silicate layers of bentonite successfully. Tetracycline was removed by heterogeneous photo-Fenton reaction using the catalyst in this work. The effects of different reaction systems, hydrogen peroxide concentration, initial pH, catalyst dosage, UV power and introduction of different anions on degradation were investigated in details. The stability of catalyst was investigated through recycling experiment. The results show that removal rate of tetracycline is 98.13% under the conditions of 15 mmol/L H202, 0.50 g/L catalyst dosage, initial pH 3.0, 11 W UV lamp power and 60 min reaction time. However, the removal rate decreases after adding some anions. The hydroxyl radical plays an important role in heterogeneous photo-assisted Fenton degradation of tetracycline. The catalyst is very stable and can be recycled many times.展开更多
Inhibition mechanism between sodium （NaaAlF6） and sulfur on coke reactivity was investigated by simulating petroleum coke with low-impurity pitch coke and by impurity doping. The mechanism was discussed by scanning ...Inhibition mechanism between sodium （NaaAlF6） and sulfur on coke reactivity was investigated by simulating petroleum coke with low-impurity pitch coke and by impurity doping. The mechanism was discussed by scanning electron microscopy, energy-dispersive spectrometry, and X-ray powder diffraction. Results show that Na effectively inhibited S catalysis during carbon-air/CO2 reactions, and S inhibited the catalysis of Na during carbon- air reaction to a certain extent. A stable structure with a Na-to-S atomic ratio of 1.4 and a cyclic reaction system of ＂Na2SO3→ Na2S→Na2CO3→ Na2SO3＂ were likely the keys to producing this mutual inhibition.展开更多
Carbon spheres with size of 50-300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave.The morphologies and microstructures of carbon spheres befor...Carbon spheres with size of 50-300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave.The morphologies and microstructures of carbon spheres before and after high temperature treatment(HTT) were characterized by X-ray diffractometry(XRD) ,scanning electronic microscopy(SEM) ,energy diffraction spectroscopy(EDS) ,and transmission electron microscopy(TEM) .The formation mechanism of carbon spheres was discussed.The results indicate that the carbon spheres convert to hollow polyhedron through HTT.Carbon spheres are composed of entangled and curve graphitic layers with short range order similar to cotton structure,and carbon polyhedron with dimension of 50-250 nm and shell thickness of 15-30 nm.The change of solid spheres to hollow polyhedron with branches gives a new evidence for formation mechanism of hollow carbon spheres.展开更多
β-Sialon/ZrN bonded corundum composites were synthesized using fused white corundum,alumina micro powder,zircon and carbon black by nitridation reaction sintering process. Phase composition and microstructure of the ...β-Sialon/ZrN bonded corundum composites were synthesized using fused white corundum,alumina micro powder,zircon and carbon black by nitridation reaction sintering process. Phase composition and microstructure of the synthesized composites were investigated by X-ray powder diffraction and scanning electronic microscope,and the formation process of the composites was discussed. The results show that the composites with different compositions can be obtained by controlling the heating temperature and contents of zircon and carbon black. The proper temperature to synthesize the composites is 1773 K.展开更多
Phosphorous slag （PHS）, ground granulated blast-furnace slag （GGBS） and fly ash （FA） were used as replacements of Portland cement to modify the microstruc^xe of recycled aggregate concrete （RAC）. A new manufac...Phosphorous slag （PHS）, ground granulated blast-furnace slag （GGBS） and fly ash （FA） were used as replacements of Portland cement to modify the microstruc^xe of recycled aggregate concrete （RAC）. A new manufacturing method named ＂W3T4＂ was proposed to improve the performances of interracial transition zone （ITZ） between recycled aggregate and mortar. The mechanical properties and the durability of RAC were tested, which show that this new manufacturing method improves the properties of RAC, and the GGBS with finest size makes a great contribution to the performance of RAC due to its better filling effect and much earlier pozzolanic reaction. Combined with GGBS, the effects of PHS on the retardation of setting time can be alleviated and the synergistic effect helps to make a more compact RAC. For the RAC with 25% of the recycled aggregate （RA） replacement and 10% PHS ＋ 10% GGBS additives, the compressive strength increases by 25.4%, but the permeability decreases by 64.3% with respect to the reference concrete made with nature aggregates. The micro-mechanisms of these improvements were investigated by the scanning electron microscope （SEM）. The SEM images show that the new manufacturing method, adding superfine pozzolanic powders and super-plasticizer benefits, makes a much denser ITZ in RAC.展开更多
Novel organic-inorganic composite photocatalyst offers new opportunities in the practical applications of photocatalysis. Novel visible light-induced Cr-doped Sr Ti O3–carbon nitride intercalation compound(CNIC) comp...Novel organic-inorganic composite photocatalyst offers new opportunities in the practical applications of photocatalysis. Novel visible light-induced Cr-doped Sr Ti O3–carbon nitride intercalation compound(CNIC) composite photocatalysts were synthesized. The composite photocatalyst was characterized by X-ray diffraction(XRD), field-emission scanning electron microscopy(FESEM), high-resolution transmission electron microscopy(HRTEM), Fourier transform infrared(FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, photoluminescence(PL) spectroscopy, and BET surface area analyzer. The photocatalytic oxidation ability of the novel composite photocatalyst was evaluated using methyl orange(MO) as a target pollutant. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO. For maximizing the photodegradation activity of the composite photocatalysts, the optimal CNIC content was determined. The improved photocatalytic activity of the as-prepared Cr-doped Sr Ti O3–CNIC composite photocatalyst may be attributed to the enhancement of photo-generated electron–hole separations at the interface.展开更多
基金Project(51004053)supported by National Natural Science Foundation of ChinaProject(2009J01033)supported by Natural Science Foundation of Fujian Province,China+2 种基金Project(3502Z20116008)supported by the Science and Technology Research Project of Xiamen City,ChinaProject(JA11146)supported by Program for Fostering Distinguished Young Scholars in University of Fujian Province,ChinaProject(2011B003)supported by the Foundation for Young Professors of Jimei University,China
文摘In the present work, a novel heterogeneous photo-Fenton catalyst was prepared by iron and cerium pillared bentonite. The catalyst Fe-Ce/bentonite was characterized by X-ray diffraction （XRD）, X-ray fluorescence （XRF）, Brunauer-Emmett-Teller （BET） and scanning electron microscopy （SEM） methods. It is found that Fe and Ce intercalate into the silicate layers of bentonite successfully. Tetracycline was removed by heterogeneous photo-Fenton reaction using the catalyst in this work. The effects of different reaction systems, hydrogen peroxide concentration, initial pH, catalyst dosage, UV power and introduction of different anions on degradation were investigated in details. The stability of catalyst was investigated through recycling experiment. The results show that removal rate of tetracycline is 98.13% under the conditions of 15 mmol/L H202, 0.50 g/L catalyst dosage, initial pH 3.0, 11 W UV lamp power and 60 min reaction time. However, the removal rate decreases after adding some anions. The hydroxyl radical plays an important role in heterogeneous photo-assisted Fenton degradation of tetracycline. The catalyst is very stable and can be recycled many times.
基金Projects(51374253,51574289)supported by the National Natural Science Foundation of China
文摘Inhibition mechanism between sodium （NaaAlF6） and sulfur on coke reactivity was investigated by simulating petroleum coke with low-impurity pitch coke and by impurity doping. The mechanism was discussed by scanning electron microscopy, energy-dispersive spectrometry, and X-ray powder diffraction. Results show that Na effectively inhibited S catalysis during carbon-air/CO2 reactions, and S inhibited the catalysis of Na during carbon- air reaction to a certain extent. A stable structure with a Na-to-S atomic ratio of 1.4 and a cyclic reaction system of ＂Na2SO3→ Na2S→Na2CO3→ Na2SO3＂ were likely the keys to producing this mutual inhibition.
基金Project(2006CB600901) supported by the National Basic Research Program of ChinaProject(0991015) supported by Guangxi Natural Science Foundation,ChinaProject(200808MS083) supported by Guangxi Education Department Foundation,China
文摘Carbon spheres with size of 50-300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave.The morphologies and microstructures of carbon spheres before and after high temperature treatment(HTT) were characterized by X-ray diffractometry(XRD) ,scanning electronic microscopy(SEM) ,energy diffraction spectroscopy(EDS) ,and transmission electron microscopy(TEM) .The formation mechanism of carbon spheres was discussed.The results indicate that the carbon spheres convert to hollow polyhedron through HTT.Carbon spheres are composed of entangled and curve graphitic layers with short range order similar to cotton structure,and carbon polyhedron with dimension of 50-250 nm and shell thickness of 15-30 nm.The change of solid spheres to hollow polyhedron with branches gives a new evidence for formation mechanism of hollow carbon spheres.
基金Project(50274021) supported by the National Natural Science Foundation of China and Baoshan Iron and Steel Co., Ltd.
文摘β-Sialon/ZrN bonded corundum composites were synthesized using fused white corundum,alumina micro powder,zircon and carbon black by nitridation reaction sintering process. Phase composition and microstructure of the synthesized composites were investigated by X-ray powder diffraction and scanning electronic microscope,and the formation process of the composites was discussed. The results show that the composites with different compositions can be obtained by controlling the heating temperature and contents of zircon and carbon black. The proper temperature to synthesize the composites is 1773 K.
基金Project(51178417)supported by the National Natural Science Foundation of ChinaProject(2012R10025)supported by the Qianjiang Talent Plan of Zhejiang Province,China+2 种基金Project(2012HY006B)supported by the Marine Cross-Guide Research Funds of Zhejiang University,ChinaProject(2013FZA4015)supported by the Fundamental Research Funds for the Central Universities,ChinaProject supported by the Department of Construction of Zhejiang Province,China
文摘Phosphorous slag （PHS）, ground granulated blast-furnace slag （GGBS） and fly ash （FA） were used as replacements of Portland cement to modify the microstruc^xe of recycled aggregate concrete （RAC）. A new manufacturing method named ＂W3T4＂ was proposed to improve the performances of interracial transition zone （ITZ） between recycled aggregate and mortar. The mechanical properties and the durability of RAC were tested, which show that this new manufacturing method improves the properties of RAC, and the GGBS with finest size makes a great contribution to the performance of RAC due to its better filling effect and much earlier pozzolanic reaction. Combined with GGBS, the effects of PHS on the retardation of setting time can be alleviated and the synergistic effect helps to make a more compact RAC. For the RAC with 25% of the recycled aggregate （RA） replacement and 10% PHS ＋ 10% GGBS additives, the compressive strength increases by 25.4%, but the permeability decreases by 64.3% with respect to the reference concrete made with nature aggregates. The micro-mechanisms of these improvements were investigated by the scanning electron microscope （SEM）. The SEM images show that the new manufacturing method, adding superfine pozzolanic powders and super-plasticizer benefits, makes a much denser ITZ in RAC.
基金Project(51208102)supported by the National Natural Science Foundation of China
文摘Novel organic-inorganic composite photocatalyst offers new opportunities in the practical applications of photocatalysis. Novel visible light-induced Cr-doped Sr Ti O3–carbon nitride intercalation compound(CNIC) composite photocatalysts were synthesized. The composite photocatalyst was characterized by X-ray diffraction(XRD), field-emission scanning electron microscopy(FESEM), high-resolution transmission electron microscopy(HRTEM), Fourier transform infrared(FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, photoluminescence(PL) spectroscopy, and BET surface area analyzer. The photocatalytic oxidation ability of the novel composite photocatalyst was evaluated using methyl orange(MO) as a target pollutant. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO. For maximizing the photodegradation activity of the composite photocatalysts, the optimal CNIC content was determined. The improved photocatalytic activity of the as-prepared Cr-doped Sr Ti O3–CNIC composite photocatalyst may be attributed to the enhancement of photo-generated electron–hole separations at the interface.
