Effects of Ti-Ce refiners on the solidification structure and the hot ductility of Fe-36Ni invar alloy were investigated, the corresponding mechanisms were also discussed. The results showed that the solidification of...Effects of Ti-Ce refiners on the solidification structure and the hot ductility of Fe-36Ni invar alloy were investigated, the corresponding mechanisms were also discussed. The results showed that the solidification of the alloy was remarkably refined with the addition of 0.05%Ti-0.01%Ce refiners. Not only did the columnar grains become shorter and thinner, but the growth pattern of them changed into staggered growth from linear growth. The alloy had a bad hot ductility below 1050 °C, which was mainly attrib-uted to weaker boundaries and the presence of grain boundary sliding. However, the hot ductility of the alloy was highly enhanced at 850-1000 °C as the addition of 0.05%Ti-0.01%Ce refiners could refine grain sizes, thus hinder grain boundary sliding, strengthen the grain boundary and promote the grain boundary movement. The alloy had a good hot ductility over 1050 °C, dynamic recrys-tallization occurred and was found to be responsible for the better hot ductility. In addition, the average coefficient of thermal ex-pansion of the alloy decreased a little with the addition of 0.05%Ti-0.01%Ce refiners, which met the requirement of material prop-erties.展开更多
Environmental risks posed by discharge of the emerging contaminant antimony(Sb) into water bodies have raised global concerns recently.The toxicity of Sb has been shown to be species-dependent,with Sb(Ⅲ) demonstratin...Environmental risks posed by discharge of the emerging contaminant antimony(Sb) into water bodies have raised global concerns recently.The toxicity of Sb has been shown to be species-dependent,with Sb(Ⅲ) demonstrating much greater toxicity than Sb(V).Here,we proposed an electrochemical filtration system to achieve rapid detoxification of Sb(Ⅲ) via a non-radical pathway.The key to this technology was an electroactive carbon nanotube filter functionalized with nanoscale Ti-Ce binary oxide.Under an electric field,in situ generated H_(2) O_(2) could react with the Ti-Ce binary oxide to produce hydroperoxide complexes,which enabled an efficient transformation of Sb(Ⅲ) to the less toxic Sb(V)(τ<2 s) at neutral pH.The impact of important operational parameters was assessed and optimized,and system efficacy could be maintained over a wide pH range and long-term operation.An optimum detoxification efficiency of> 90% was achieved using lake water spiked with Sb(Ⅲ) at 500 μg/L.The results showed that Ti/Ce-hydroperoxo surface complexes were the dominant species responsible for the non-radical oxidation of Sb(Ⅲ) based on extensive experimental evidences and advanced characterizations.This study provides a robust and effective strategy for the detoxification of water containing Sb(Ⅲ) and other similar heavy metal ions by integrating state-of-the-art advanced oxidation processes,electrochemistry and nano-filtration technology.展开更多
A series of copper-doped Ti-Ce-O_x complex oxide catalysts were synthesized by sol-gel method and evaluated for selective catalytic reduction of NO by NH_3 at low temperature. The promotional effect of copper doping o...A series of copper-doped Ti-Ce-O_x complex oxide catalysts were synthesized by sol-gel method and evaluated for selective catalytic reduction of NO by NH_3 at low temperature. The promotional effect of copper doping on their structure, acidity and catalytic activity were investigated by means of Brumauer-Emmett-Teller（BET）, temperature-programmed reduction（H_2-TPR）, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, temperature programmed desorption（NH_3-TPD） and pyridine adsorption infrared spectrum（Py-IR） technologies. Results showed that the copper additives could improve the low temperature catalytic performance for selective catalytic reduction of Ti-Ce-O_x catalyst and the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached above 90% at 150-250 oC（Ti/Cu=4）. The introduction of copper could enhance the redox property of the Ti-Ce-O_x complex oxide catalyst, refine the particle size caused by lattice distortion and oxygen vacancy defect and enhance the acid amount of the Lewis acid site. Moreover, Ti-Cu-Ce-O_x complex oxide catalyst also had good anti-sulfur ability and anti-water influence, when injecting 300 ppm SO_2 and 10 vol.%H_2O, the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached 80%.展开更多
文摘Effects of Ti-Ce refiners on the solidification structure and the hot ductility of Fe-36Ni invar alloy were investigated, the corresponding mechanisms were also discussed. The results showed that the solidification of the alloy was remarkably refined with the addition of 0.05%Ti-0.01%Ce refiners. Not only did the columnar grains become shorter and thinner, but the growth pattern of them changed into staggered growth from linear growth. The alloy had a bad hot ductility below 1050 °C, which was mainly attrib-uted to weaker boundaries and the presence of grain boundary sliding. However, the hot ductility of the alloy was highly enhanced at 850-1000 °C as the addition of 0.05%Ti-0.01%Ce refiners could refine grain sizes, thus hinder grain boundary sliding, strengthen the grain boundary and promote the grain boundary movement. The alloy had a good hot ductility over 1050 °C, dynamic recrys-tallization occurred and was found to be responsible for the better hot ductility. In addition, the average coefficient of thermal ex-pansion of the alloy decreased a little with the addition of 0.05%Ti-0.01%Ce refiners, which met the requirement of material prop-erties.
基金supported by the Natural Science Foundation of Shanghai,China (No.18ZR1401000)。
文摘Environmental risks posed by discharge of the emerging contaminant antimony(Sb) into water bodies have raised global concerns recently.The toxicity of Sb has been shown to be species-dependent,with Sb(Ⅲ) demonstrating much greater toxicity than Sb(V).Here,we proposed an electrochemical filtration system to achieve rapid detoxification of Sb(Ⅲ) via a non-radical pathway.The key to this technology was an electroactive carbon nanotube filter functionalized with nanoscale Ti-Ce binary oxide.Under an electric field,in situ generated H_(2) O_(2) could react with the Ti-Ce binary oxide to produce hydroperoxide complexes,which enabled an efficient transformation of Sb(Ⅲ) to the less toxic Sb(V)(τ<2 s) at neutral pH.The impact of important operational parameters was assessed and optimized,and system efficacy could be maintained over a wide pH range and long-term operation.An optimum detoxification efficiency of> 90% was achieved using lake water spiked with Sb(Ⅲ) at 500 μg/L.The results showed that Ti/Ce-hydroperoxo surface complexes were the dominant species responsible for the non-radical oxidation of Sb(Ⅲ) based on extensive experimental evidences and advanced characterizations.This study provides a robust and effective strategy for the detoxification of water containing Sb(Ⅲ) and other similar heavy metal ions by integrating state-of-the-art advanced oxidation processes,electrochemistry and nano-filtration technology.
基金supported by the National Natural Science Foundation of China(51272105)the National Key Technology R&D Program of China(2012BAE01B03)+1 种基金the Research Subject of Environmental Protection Department of Jiangsu Province of China(2013006)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘A series of copper-doped Ti-Ce-O_x complex oxide catalysts were synthesized by sol-gel method and evaluated for selective catalytic reduction of NO by NH_3 at low temperature. The promotional effect of copper doping on their structure, acidity and catalytic activity were investigated by means of Brumauer-Emmett-Teller（BET）, temperature-programmed reduction（H_2-TPR）, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, temperature programmed desorption（NH_3-TPD） and pyridine adsorption infrared spectrum（Py-IR） technologies. Results showed that the copper additives could improve the low temperature catalytic performance for selective catalytic reduction of Ti-Ce-O_x catalyst and the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached above 90% at 150-250 oC（Ti/Cu=4）. The introduction of copper could enhance the redox property of the Ti-Ce-O_x complex oxide catalyst, refine the particle size caused by lattice distortion and oxygen vacancy defect and enhance the acid amount of the Lewis acid site. Moreover, Ti-Cu-Ce-O_x complex oxide catalyst also had good anti-sulfur ability and anti-water influence, when injecting 300 ppm SO_2 and 10 vol.%H_2O, the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached 80%.
