Magnetic-luminescent nanocomposites have obtained a great deal of attention due to their potential applications in magnetic separation of cells, magnetic resonance imaging and luminescence imaging, and so on. Herein, ...Magnetic-luminescent nanocomposites have obtained a great deal of attention due to their potential applications in magnetic separation of cells, magnetic resonance imaging and luminescence imaging, and so on. Herein, a new and facile two-step synthetic strategy was developed to prepare magnetic Fe304 modified single crystalline up- conversion luminescent NaYF4： Yb3＋, Er3＋ nanocrystals using Fe304 nanoparticles as the seeds. Acting as the ＂nu- clei＂ in the reaction, the presence of Fe304 nanoparticles facilitates the formation of up-conversion NaYF4： Yb3＋, Er3＋ nanocrystals on their surfaces through heterogeneous nucleation process. The structure and properties of these multifunctional nanocrystals were characterized by transmission electron microscope （TEM）, X-ray photoelectron spectroscopy （XPS）, photo luminescence （PL） and X-ray diffraction （XRD）. The results revealed that the as-prepared multifunctional nanocrystals show dual distinct properties of up-conversion fluorescent and superpara- magnetism, which were cubic in shape and very uniform in size with an average size ranging 30m40 nm. These unique functionalities could be very attractive for biological systems, and some biological applications such as cell- labelling were also demonstrated.展开更多
The modified Fe3O4 nanoparticles with the extracted pectin from the cell wall of Azolla filicoloides（FNEP） can remove methyl orange as a watersoluble azo dye from waste water better than Azolla and the extracted pec...The modified Fe3O4 nanoparticles with the extracted pectin from the cell wall of Azolla filicoloides（FNEP） can remove methyl orange as a watersoluble azo dye from waste water better than Azolla and the extracted pectin from Azolla（EPA）,alone.It could be due to more crowding the main functional groups of uptake after binding pectin with nanoparticles.Thermodynamic studies showed that adsorption equilibrium constant（KL） and maximum adsorption capacities（Q（max）） were increased with decreasing temperature（exothermic）.The maximum uptake capacity（Q（max）） of dye by FNEP in a batch reactor was 0.533,0.498 and 0.446 mmol/g at 5,25 and 50℃,respectively.The enthalpy change（△H） and entropy change（△S） were 15.31 kJ/mol and 0.02434 kJ/mol K,respectively.展开更多
基金supported by Major Basic Research Programme of Science and Technology Commission of Shanghai Municipality （No. 10JC1403200）, Shuguang Talents Programme of Edu- cation Commission of Shanghai Municipality （No. 09SG27）, National Natural Science Foundation of China （Nos. 20973059, 91022023, 21076076）, Fundamental Research Funds for the Central Universities （No. WJ0913001）, Program for Professor of Special Appointment （Eastern Scholar） at Shanghai Institutions of Higher Learning and Program for New Century Excel- lent Talents in University （No. NCET-09-0347）.
文摘Magnetic-luminescent nanocomposites have obtained a great deal of attention due to their potential applications in magnetic separation of cells, magnetic resonance imaging and luminescence imaging, and so on. Herein, a new and facile two-step synthetic strategy was developed to prepare magnetic Fe304 modified single crystalline up- conversion luminescent NaYF4： Yb3＋, Er3＋ nanocrystals using Fe304 nanoparticles as the seeds. Acting as the ＂nu- clei＂ in the reaction, the presence of Fe304 nanoparticles facilitates the formation of up-conversion NaYF4： Yb3＋, Er3＋ nanocrystals on their surfaces through heterogeneous nucleation process. The structure and properties of these multifunctional nanocrystals were characterized by transmission electron microscope （TEM）, X-ray photoelectron spectroscopy （XPS）, photo luminescence （PL） and X-ray diffraction （XRD）. The results revealed that the as-prepared multifunctional nanocrystals show dual distinct properties of up-conversion fluorescent and superpara- magnetism, which were cubic in shape and very uniform in size with an average size ranging 30m40 nm. These unique functionalities could be very attractive for biological systems, and some biological applications such as cell- labelling were also demonstrated.
文摘The modified Fe3O4 nanoparticles with the extracted pectin from the cell wall of Azolla filicoloides（FNEP） can remove methyl orange as a watersoluble azo dye from waste water better than Azolla and the extracted pectin from Azolla（EPA）,alone.It could be due to more crowding the main functional groups of uptake after binding pectin with nanoparticles.Thermodynamic studies showed that adsorption equilibrium constant（KL） and maximum adsorption capacities（Q（max）） were increased with decreasing temperature（exothermic）.The maximum uptake capacity（Q（max）） of dye by FNEP in a batch reactor was 0.533,0.498 and 0.446 mmol/g at 5,25 and 50℃,respectively.The enthalpy change（△H） and entropy change（△S） were 15.31 kJ/mol and 0.02434 kJ/mol K,respectively.
