By using a new method, ^60Co γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanop...By using a new method, ^60Co γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM） and vibrating sample magnetometer （VSM）, respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation （10 kGy） is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation （10 kGy） are mainly in small cubic shape and the size uniformity of these particles is good.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
γ-Fe nano-particles with size of 20-40 nm were produced by SF6-sensitized CW CO2 laser-induced gaseous pyrolysis of Fe(Co) 5, The γ-Fe stabte in reaction zone at above 910℃ was formed.The rapid quenching prevents f...γ-Fe nano-particles with size of 20-40 nm were produced by SF6-sensitized CW CO2 laser-induced gaseous pyrolysis of Fe(Co) 5, The γ-Fe stabte in reaction zone at above 910℃ was formed.The rapid quenching prevents from the γ-Fe transforming to α-Fe as rapidly cooling from high temperature to room temperature, The characteristics of the particles were examined at room temperature by TEM. electron diffraction and XRD. It was proved that about 70% of γ-Fe phase in the particles was present. In addition. the lattice constant of the γ-Fe was 0.364 nm in place of 0.360 nm展开更多
基金This work was supported by the Natural Science Foundation of Henan Province under grant No. 0611023900.
文摘By using a new method, ^60Co γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM） and vibrating sample magnetometer （VSM）, respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation （10 kGy） is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation （10 kGy） are mainly in small cubic shape and the size uniformity of these particles is good.
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.
文摘γ-Fe nano-particles with size of 20-40 nm were produced by SF6-sensitized CW CO2 laser-induced gaseous pyrolysis of Fe(Co) 5, The γ-Fe stabte in reaction zone at above 910℃ was formed.The rapid quenching prevents from the γ-Fe transforming to α-Fe as rapidly cooling from high temperature to room temperature, The characteristics of the particles were examined at room temperature by TEM. electron diffraction and XRD. It was proved that about 70% of γ-Fe phase in the particles was present. In addition. the lattice constant of the γ-Fe was 0.364 nm in place of 0.360 nm
