Fe3O4/MWCNTs nanocomposites were prepared by chemical oxidation coprecipitation method and developed as highly efficient heterogeneous Fenton-like catalyst. XRD results revealed that Fe3O4 nanoparticles deposited onto...Fe3O4/MWCNTs nanocomposites were prepared by chemical oxidation coprecipitation method and developed as highly efficient heterogeneous Fenton-like catalyst. XRD results revealed that Fe3O4 nanoparticles deposited onto MWCNTs surface remained the inverse spinel crystal structure of cubic Fe3O4 phase. The FTIR characteristic peaks of MWCNTs weakened or disappeared due to the anchor of Fe3O4 nanoparticles and Fe-O peak at 570 cm^-1 was indicative of the formation of Fe3O4. TEM observation revealed that Fe3O4 nanoparticles were tightly anchored by MWCNTs. The Fenton-like catalytic activity of Fe3O4/MWCNTs nanocomposites for the discoloration of methyl orange （MO） was much higher than that of Fe3O4 nanoparticles. The process optimization of this heterogeneous Fenton-like system was implemented by response surface methodology （RSM）. The optimum conditions for MO discoloration were determined to be of 12.3 mmoi/L H2O2 concentration, 2.9 glL catalyst dosage, solution pH 2.7 and 39.3 min reaction time, with the maximum predicted value for MO discoloration ratio of 101.85%. The corresponding experimental value under the identical conditions was obtained as 99.86%, which was very close to the predicted one with the absolute deviation of 1.99%.展开更多
Multi-walled carbon nanotubes （MWCNTs） can act not only as a support for Fe3O4 nanoparticles （NPs） but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of ...Multi-walled carbon nanotubes （MWCNTs） can act not only as a support for Fe3O4 nanoparticles （NPs） but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of Fe3O4 NPs. In this study, Fe3O4 NPs were in situ anchored onto MWCNTs by a moderate co-precipitation method and the as-prepared Fe3O4/MWCNTs nanocomposites were employed as the highly efficient Fenton-like catalysts. The analyses of XRD, FTIR, Raman, FESEM, TEM and HRTEM results indicated the formation of Fe3O4 crystals in Fe3O4/MWCNTs nanocomposites prepared at different conditions and the interaction between Fe3O4 NPs and MWCNTs. Over a wide pH range, the surface of modified MWCNTs possessed negative charges. Based on these results, the possible combination mechanism between Fe3O4 NPs and MWCNTs was discussed and proposed. Moreover, the effects of preparation and catalytic conditions on the Fenton-like catalytic efficiency were investigated in order to gain further insight into the heterogeneous Fenton-like reaction catalyzed by Fe3O4/MWCNTs nanocomposites.展开更多
The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe3O4/...The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe3O4/MWCNTs-H2O2 Fenton-like reaction for MO degradation. The results indicated that this reaction followed the first- order kinetic model. The relationship of reaction rate constant and temperature followed the Arrhenius equation. The activation energy and frequency factor of this system were calculated as 8.2 kJ.mo1-1 and 2.72 s-1, respectively. The quantifications of Fe ions dissolution and ,OH radicals generation confirmed that the homogeneous and hetero- geneous catalyses were involved in Fe3O4/MWCNTs＇H2O2 Fenton-like reaction. The reaction rate constant was closely related with Fe ions dissolution and ,OH radicals generation. Fe3O4/MWCNTs nanocomposites had typical ferromagnetic property and could be easily separated from solution by an external magnet after being used. Furthermore, Fe3O4/MWCNTs nanocomposites exhibited good stability and recyclability. Finally, the Fenton-like mechanisms on homogeneous and heterogeneous catalyses were described.展开更多
基金Acknowledgements This work was kindly supported by the National Natural Science Foundation of China （Grant Nos. 51404083 and 21273060）, the Natural Science Foundation of Heilongjiang Province （E2015065） and the Program for New Century Excellent Talents in Heilongjiang Provincial Universities （1253-NCET-010）.
文摘Fe3O4/MWCNTs nanocomposites were prepared by chemical oxidation coprecipitation method and developed as highly efficient heterogeneous Fenton-like catalyst. XRD results revealed that Fe3O4 nanoparticles deposited onto MWCNTs surface remained the inverse spinel crystal structure of cubic Fe3O4 phase. The FTIR characteristic peaks of MWCNTs weakened or disappeared due to the anchor of Fe3O4 nanoparticles and Fe-O peak at 570 cm^-1 was indicative of the formation of Fe3O4. TEM observation revealed that Fe3O4 nanoparticles were tightly anchored by MWCNTs. The Fenton-like catalytic activity of Fe3O4/MWCNTs nanocomposites for the discoloration of methyl orange （MO） was much higher than that of Fe3O4 nanoparticles. The process optimization of this heterogeneous Fenton-like system was implemented by response surface methodology （RSM）. The optimum conditions for MO discoloration were determined to be of 12.3 mmoi/L H2O2 concentration, 2.9 glL catalyst dosage, solution pH 2.7 and 39.3 min reaction time, with the maximum predicted value for MO discoloration ratio of 101.85%. The corresponding experimental value under the identical conditions was obtained as 99.86%, which was very close to the predicted one with the absolute deviation of 1.99%.
基金This work was financially supported by the Natural Science Foundation of Heilongjiang Province, China （No. E2015065）.
文摘Multi-walled carbon nanotubes （MWCNTs） can act not only as a support for Fe3O4 nanoparticles （NPs） but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of Fe3O4 NPs. In this study, Fe3O4 NPs were in situ anchored onto MWCNTs by a moderate co-precipitation method and the as-prepared Fe3O4/MWCNTs nanocomposites were employed as the highly efficient Fenton-like catalysts. The analyses of XRD, FTIR, Raman, FESEM, TEM and HRTEM results indicated the formation of Fe3O4 crystals in Fe3O4/MWCNTs nanocomposites prepared at different conditions and the interaction between Fe3O4 NPs and MWCNTs. Over a wide pH range, the surface of modified MWCNTs possessed negative charges. Based on these results, the possible combination mechanism between Fe3O4 NPs and MWCNTs was discussed and proposed. Moreover, the effects of preparation and catalytic conditions on the Fenton-like catalytic efficiency were investigated in order to gain further insight into the heterogeneous Fenton-like reaction catalyzed by Fe3O4/MWCNTs nanocomposites.
基金This work was financially supported by the Natural Science Foundation of Heilongjiang Province, China （Grant No. E2015065）.
文摘The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe3O4/MWCNTs-H2O2 Fenton-like reaction for MO degradation. The results indicated that this reaction followed the first- order kinetic model. The relationship of reaction rate constant and temperature followed the Arrhenius equation. The activation energy and frequency factor of this system were calculated as 8.2 kJ.mo1-1 and 2.72 s-1, respectively. The quantifications of Fe ions dissolution and ,OH radicals generation confirmed that the homogeneous and hetero- geneous catalyses were involved in Fe3O4/MWCNTs＇H2O2 Fenton-like reaction. The reaction rate constant was closely related with Fe ions dissolution and ,OH radicals generation. Fe3O4/MWCNTs nanocomposites had typical ferromagnetic property and could be easily separated from solution by an external magnet after being used. Furthermore, Fe3O4/MWCNTs nanocomposites exhibited good stability and recyclability. Finally, the Fenton-like mechanisms on homogeneous and heterogeneous catalyses were described.
