Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium r...Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium retention and thermal desorption behaviors are key issues for the applications of vanadium alloys in fusion reactors since helium can be produced by helium discharge cleaning and neutron transmutation. A. van Veen groupt investigated helium trapping and thermal desorption mechanisms in vanadium alloys by using 1 keV helium ion irradiation to the fluence of 10^13～10^14He/cm^2, and the influenee of pre-annealing treatments on helium trapping. Two group of peaks were found at the thermal helium desorption spectrum. They thought one was due to helium-vacancyimpurity clusters and the other was corresponding to helium trapping into pre-existing traps, such as fine-size precipitates.展开更多
Halo-olefinic impurities in 1,1,1,3,3-pentafluoropropane （HFC-245fa） product used as blowing agents, etc. could damage the human body and must be removed. Activated carbon was treated by HCI, HN03 and NaOH, respecti...Halo-olefinic impurities in 1,1,1,3,3-pentafluoropropane （HFC-245fa） product used as blowing agents, etc. could damage the human body and must be removed. Activated carbon was treated by HCI, HN03 and NaOH, respectively. The adsorptive performance of unmodified and modified activated carbons for the removal of a low con- tent of l-chloro-3,3,3-trifluoro-l-propene （HCFC-1233zd）, 1,3,3,3-tetrafluoro-l-propene （HFC-1234ze）, 1- chloro-l,3,3,3-tetrafluoro-l-propene （HFC-1224zb） and 2-chloro-l,3,3,3-tetrafluoro-l-propene （HFC-1224xe） halo-olefins in the 1,1,1,3,3-pentafluoropropane （HFC-245fa] product was investigated. These halo-olefinic im- purities could be substantially removed from the HFC-245fa product via the adsorption over activated carbon when the adsorption temperature was under 333 K, which can be attributed to the n-n dispersion interactions between the halo-olefins and carbon graphite layer. The basic surface groups of activated carbon could catalyze the decomposition of HFC-245fa to form HFC-1234ze. However, the significant increase in the amount of surface acidic groups of activated carbon led to a distinct decrease of adsorption capacity due to the reduction in the mi- cropore volume of adsorbent and a decrease in the strength of the n-n dispersive interactions between halo- olefin molecules and carbon basal. The breakthrough time of halo-olefinic impurities on activated carbon in- creased with the increase of molecular mass and the decrease of molecular symmetry.展开更多
In this study,a clew-like ZnO superstructure was synthesized by a copolymer-controlled self-assembly homogeneous precipitation method. Ni was impregnated to the clew-like ZnO superstructure to obtain Ni/ZnO adsorbents...In this study,a clew-like ZnO superstructure was synthesized by a copolymer-controlled self-assembly homogeneous precipitation method. Ni was impregnated to the clew-like ZnO superstructure to obtain Ni/ZnO adsorbents.The synthesized materials were characterized by scanning electron microscopy,transmission electron microscopy,N_2 sorption,X-ray diffraction,Fourier transform infrared spectrometry,and H2-temperature programmed reduction techniques. The reactive adsorption desulfurization（RADS）performance of the adsorbents was evaluated in a fixed bed reactor using thiophene in n-octane as a model fuel. Sample Ni/ZnO-4h exhibits a remarkably high performance with a sulfur capacity of 189.1 mg S g^（-1）,which is above 6 times that of the one prepared with commercial ZnO. Characterization results show that the morphology changes from micro-clews to large solid sticks with the increase of the crystallization time.The loose and open architecture of the clew-like ZnO superstructure facilitates the diffusion of reactants/products,and prevents the adsorbent particles from breakage by supplying space for the volume expansion during the RADS process. The small nanoparticles in ZnO nanostrips result in a high sulfur adsorption capacity and also favor the dispersion of Ni,leading to an excellent RADS performance.展开更多
文摘Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium retention and thermal desorption behaviors are key issues for the applications of vanadium alloys in fusion reactors since helium can be produced by helium discharge cleaning and neutron transmutation. A. van Veen groupt investigated helium trapping and thermal desorption mechanisms in vanadium alloys by using 1 keV helium ion irradiation to the fluence of 10^13～10^14He/cm^2, and the influenee of pre-annealing treatments on helium trapping. Two group of peaks were found at the thermal helium desorption spectrum. They thought one was due to helium-vacancyimpurity clusters and the other was corresponding to helium trapping into pre-existing traps, such as fine-size precipitates.
基金Supported by the Major Project of Green Chemical Industry of Zhejiang Province(2007C11043)
文摘Halo-olefinic impurities in 1,1,1,3,3-pentafluoropropane （HFC-245fa） product used as blowing agents, etc. could damage the human body and must be removed. Activated carbon was treated by HCI, HN03 and NaOH, respectively. The adsorptive performance of unmodified and modified activated carbons for the removal of a low con- tent of l-chloro-3,3,3-trifluoro-l-propene （HCFC-1233zd）, 1,3,3,3-tetrafluoro-l-propene （HFC-1234ze）, 1- chloro-l,3,3,3-tetrafluoro-l-propene （HFC-1224zb） and 2-chloro-l,3,3,3-tetrafluoro-l-propene （HFC-1224xe） halo-olefins in the 1,1,1,3,3-pentafluoropropane （HFC-245fa] product was investigated. These halo-olefinic im- purities could be substantially removed from the HFC-245fa product via the adsorption over activated carbon when the adsorption temperature was under 333 K, which can be attributed to the n-n dispersion interactions between the halo-olefins and carbon graphite layer. The basic surface groups of activated carbon could catalyze the decomposition of HFC-245fa to form HFC-1234ze. However, the significant increase in the amount of surface acidic groups of activated carbon led to a distinct decrease of adsorption capacity due to the reduction in the mi- cropore volume of adsorbent and a decrease in the strength of the n-n dispersive interactions between halo- olefin molecules and carbon basal. The breakthrough time of halo-olefinic impurities on activated carbon in- creased with the increase of molecular mass and the decrease of molecular symmetry.
基金supported by the Joint Funds of the National Natural Science Foundation of China and China National Petroleum Corporation(U1362202)the National Natural Science Foundation of China(51601223 and 21206195)+2 种基金the Fundamental Research Funds for the Central Universities(17CX05018,17CX02056 and YCX2017039)Shandong Provincial Natural Science Foundation(ZR2012BM014)the project sponsored by Scientific Research Foundation for Returned Overseas Chinese Scholars
文摘In this study,a clew-like ZnO superstructure was synthesized by a copolymer-controlled self-assembly homogeneous precipitation method. Ni was impregnated to the clew-like ZnO superstructure to obtain Ni/ZnO adsorbents.The synthesized materials were characterized by scanning electron microscopy,transmission electron microscopy,N_2 sorption,X-ray diffraction,Fourier transform infrared spectrometry,and H2-temperature programmed reduction techniques. The reactive adsorption desulfurization（RADS）performance of the adsorbents was evaluated in a fixed bed reactor using thiophene in n-octane as a model fuel. Sample Ni/ZnO-4h exhibits a remarkably high performance with a sulfur capacity of 189.1 mg S g^（-1）,which is above 6 times that of the one prepared with commercial ZnO. Characterization results show that the morphology changes from micro-clews to large solid sticks with the increase of the crystallization time.The loose and open architecture of the clew-like ZnO superstructure facilitates the diffusion of reactants/products,and prevents the adsorbent particles from breakage by supplying space for the volume expansion during the RADS process. The small nanoparticles in ZnO nanostrips result in a high sulfur adsorption capacity and also favor the dispersion of Ni,leading to an excellent RADS performance.
