Chlorinated phenols are a kind of environmental priority pollutants that attract much attention. The effect of Ni on the removal of pentachlorophenol （PCP） with Fe nanoparticles was investigated in this study. Fe na...Chlorinated phenols are a kind of environmental priority pollutants that attract much attention. The effect of Ni on the removal of pentachlorophenol （PCP） with Fe nanoparticles was investigated in this study. Fe nanoparticles and Ni submicron particles were synthesized using chemical reduction method and wet chemical techniques, respectively. And the concentrations of PCP and chloride ion in solutions were measured with and without Ni present. The results showed that the dechlorination of PCP was promoted in the presence of Ni particles, and the dechlorination efficiency was reduced along with the increase of Ni size. When the diameter of Ni particle was smaller than 300 nm, the removal efficiency of PCP was obviously increased in the initial 4 h, and then became the similar to that of the system with Fe only. When the diameter of Ni particle was between 400 nm and 1 μm, the removal efficiency of PCP was increased in the initial 1 h. Then the removal of PCP was inhibited, and the inhibition was increased with the increase of Ni size. Later, the removal efficiency was the similar in various systems.展开更多
In this study,we compared FeNi alloy magnetic nanoparticles(MNPs) prepared by either combustion or chemical precipitation methods.We found that the FeNi MNPs generated by combustion method have a rather high saturatio...In this study,we compared FeNi alloy magnetic nanoparticles(MNPs) prepared by either combustion or chemical precipitation methods.We found that the FeNi MNPs generated by combustion method have a rather high saturation magnetization Ms of ～180 emu/g and a coercivity field Hc of near zero.However,the alloy nanoparticles are easily aggregated and are not well dispersive such that size distribution of the nanoparticle clusters is wide and clusters are rather big(around 50～700 nm).To prepare a better quality and well dispersed Fe-Ni MNPs,we also developed a thermal reflux chemical precipitation method to synthesize FeNi3 alloy MNPs.The precursor chemicals of Fe(acac)3 and Ni(acac)2 in a molecular ratio of 1:3 reacted in octyl ether solvent at the boiling point of solvent(～300 ℃) by the thermal reflux process.The 1,2-hexadecandiol and tri-n-octylphosphine oxide(TOPO) were used as reducer and surfactant,respectively.The chemically precipitated FeNi3 MNPs are well dispersed and have well-controlled particle sizes around 10～20 nm with a very narrow size distribution(±1.2 nm).The highly monodispersive FeNi3 MNPs present good uniformity in particle shape and crystallinity on particle surfaces.The MNPs exhibit well soft magnetism with saturation magnetization of ～61 emu/g and Hc～0.The biomedically compatible FeNi MNPs which were coated with biocompatible polyethyleneimine(PEI) polymer were also synthesized.We demonstrated that the PEI coated FeNi MNPs can enter the mammalian cells in vitro and can be used as a magnetic resonance imagine(MRI) contrast agent.The results demonstrated that FeNi MNPs potentially could be applied in the biomedical field.The functionalized magnetic beads with biocompatible polymer coated on MNPs are also completed for biomedical applications.展开更多
采用油包水（W/O）微乳液法,以KBH4为还原剂,在水相-Triton X 100-异丙醇-环己烷组成的W/O微乳液中还原二价铁、钴、镍盐,合成Fe-Co-Ni合金纳米微粒。考察反应气氛、温度、时间和洗涤溶液对反应的影响,并用X射线衍射仪、扫描电子显微镜...采用油包水（W/O）微乳液法,以KBH4为还原剂,在水相-Triton X 100-异丙醇-环己烷组成的W/O微乳液中还原二价铁、钴、镍盐,合成Fe-Co-Ni合金纳米微粒。考察反应气氛、温度、时间和洗涤溶液对反应的影响,并用X射线衍射仪、扫描电子显微镜对合成的纳米微粒的形貌、结构进行检测。研究结果表明：在25-30℃的N2中反应1 h,得到的产物待丙酮破乳后用无水乙醇洗涤结果最佳。合成的Fe-Co-Ni合金是粒径为1-3 nm的球状微粒。展开更多
Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM ...Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM （transmission electron microscope）, XRD （X-ray diffractometer）, and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol （p-CP） as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L （Ni 5 wt%）. The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.展开更多
Fe_(0.64)Ni_(0.36)-NiFe_2O_4 nanocomposite was performed with partially reducing NiFe_2O_4 nanoparticles in Ar/H_2 ambient.The microwave and static magnetic properties were investigated.The results showed that the nan...Fe_(0.64)Ni_(0.36)-NiFe_2O_4 nanocomposite was performed with partially reducing NiFe_2O_4 nanoparticles in Ar/H_2 ambient.The microwave and static magnetic properties were investigated.The results showed that the nanocomposite was characterized with enhanced microwave absorption properties.The optimal reflection loss(RL)of the nanocomposite reached-24.8 dB at 14 GHz for an absorber thickness of 1.5 mm.Meanwhile,a broad bandwidth for RL<-10 dB was obtained in the range of 3.1—15.1 GHz for an absorber thickness from1.0 to 4.0 mm.The enhancement is attributed to the increase of dielectric and magnetic loss after reducing procedure.展开更多
基金Supported by the National Natural Science Foundation(51108454)
文摘Chlorinated phenols are a kind of environmental priority pollutants that attract much attention. The effect of Ni on the removal of pentachlorophenol （PCP） with Fe nanoparticles was investigated in this study. Fe nanoparticles and Ni submicron particles were synthesized using chemical reduction method and wet chemical techniques, respectively. And the concentrations of PCP and chloride ion in solutions were measured with and without Ni present. The results showed that the dechlorination of PCP was promoted in the presence of Ni particles, and the dechlorination efficiency was reduced along with the increase of Ni size. When the diameter of Ni particle was smaller than 300 nm, the removal efficiency of PCP was obviously increased in the initial 4 h, and then became the similar to that of the system with Fe only. When the diameter of Ni particle was between 400 nm and 1 μm, the removal efficiency of PCP was increased in the initial 1 h. Then the removal of PCP was inhibited, and the inhibition was increased with the increase of Ni size. Later, the removal efficiency was the similar in various systems.
文摘In this study,we compared FeNi alloy magnetic nanoparticles(MNPs) prepared by either combustion or chemical precipitation methods.We found that the FeNi MNPs generated by combustion method have a rather high saturation magnetization Ms of ～180 emu/g and a coercivity field Hc of near zero.However,the alloy nanoparticles are easily aggregated and are not well dispersive such that size distribution of the nanoparticle clusters is wide and clusters are rather big(around 50～700 nm).To prepare a better quality and well dispersed Fe-Ni MNPs,we also developed a thermal reflux chemical precipitation method to synthesize FeNi3 alloy MNPs.The precursor chemicals of Fe(acac)3 and Ni(acac)2 in a molecular ratio of 1:3 reacted in octyl ether solvent at the boiling point of solvent(～300 ℃) by the thermal reflux process.The 1,2-hexadecandiol and tri-n-octylphosphine oxide(TOPO) were used as reducer and surfactant,respectively.The chemically precipitated FeNi3 MNPs are well dispersed and have well-controlled particle sizes around 10～20 nm with a very narrow size distribution(±1.2 nm).The highly monodispersive FeNi3 MNPs present good uniformity in particle shape and crystallinity on particle surfaces.The MNPs exhibit well soft magnetism with saturation magnetization of ～61 emu/g and Hc～0.The biomedically compatible FeNi MNPs which were coated with biocompatible polyethyleneimine(PEI) polymer were also synthesized.We demonstrated that the PEI coated FeNi MNPs can enter the mammalian cells in vitro and can be used as a magnetic resonance imagine(MRI) contrast agent.The results demonstrated that FeNi MNPs potentially could be applied in the biomedical field.The functionalized magnetic beads with biocompatible polymer coated on MNPs are also completed for biomedical applications.
文摘采用油包水（W/O）微乳液法,以KBH4为还原剂,在水相-Triton X 100-异丙醇-环己烷组成的W/O微乳液中还原二价铁、钴、镍盐,合成Fe-Co-Ni合金纳米微粒。考察反应气氛、温度、时间和洗涤溶液对反应的影响,并用X射线衍射仪、扫描电子显微镜对合成的纳米微粒的形貌、结构进行检测。研究结果表明：在25-30℃的N2中反应1 h,得到的产物待丙酮破乳后用无水乙醇洗涤结果最佳。合成的Fe-Co-Ni合金是粒径为1-3 nm的球状微粒。
基金Project supported by the National Basic Research Program (973) of China(No. 2003CB415006)the National Natural Science Foundation of China (No. 20337020)
文摘Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM （transmission electron microscope）, XRD （X-ray diffractometer）, and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol （p-CP） as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L （Ni 5 wt%）. The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.
基金supported by National Science Fund for Distinguished Young Scholars (Grant No.50925103)the National Nature Science Foundation of China (Grant No.11034004)
文摘Fe_(0.64)Ni_(0.36)-NiFe_2O_4 nanocomposite was performed with partially reducing NiFe_2O_4 nanoparticles in Ar/H_2 ambient.The microwave and static magnetic properties were investigated.The results showed that the nanocomposite was characterized with enhanced microwave absorption properties.The optimal reflection loss(RL)of the nanocomposite reached-24.8 dB at 14 GHz for an absorber thickness of 1.5 mm.Meanwhile,a broad bandwidth for RL<-10 dB was obtained in the range of 3.1—15.1 GHz for an absorber thickness from1.0 to 4.0 mm.The enhancement is attributed to the increase of dielectric and magnetic loss after reducing procedure.
