Magnetic MnFe2O4-bentonite was synthesized by chemical co-precipitation method（CCM） and applied as catalyst in heterogeneous activation of persulfate（PS） to oxidize a target pollutant, 2,4-dichlorophenol（2,4-DCP...Magnetic MnFe2O4-bentonite was synthesized by chemical co-precipitation method（CCM） and applied as catalyst in heterogeneous activation of persulfate（PS） to oxidize a target pollutant, 2,4-dichlorophenol（2,4-DCP）, in aqueous solutions. The surface morphology and structure of MnFe2On-bentonite were characterized by X-ray diffraction（XRD）, scanning electron microscope（SEM）, energy dispersive X-ray（EDX） and X-ray photoelectron spectroscopy（XPS） analyses.The catalytic activity of MnFe2O4-bentonite for 2,4-DCP degradation was evaluated considering the effects of various process parameters, such as mass ratio of MnFe2O4 to bentonite, concentration of catalyst, PS concentration, and pH. The MnFe2O4-bentonite hybrid exhibited higher catalytic activity than pure MnFe2O4. Treatment with 5 g/L MnFe2O4-bentonite at 30℃ for 240 rain oxidized 92% of 100 mg/L 2,4-DCP（70.2% mineralization）, whereas treatment with pure MnFe2O4 under the same condition oxidized only 70% of the pollutant. This result indicate the erdlanced performance of the activated PS. Moreover, MnFe2O4-bentonite exhibits stable performance with minimal loss in activity after five successive runs. Thus, MnFe2O4-bentonite could be a promising catalyst in oxidative degradation of 2,4-DCE展开更多
In this article,MnFe2O4 nanocrystals were synthesized by coprecipitation at low temperature,and the effects of temperature,time and additive on crystallization and particle sizes of samples were also studied.In additi...In this article,MnFe2O4 nanocrystals were synthesized by coprecipitation at low temperature,and the effects of temperature,time and additive on crystallization and particle sizes of samples were also studied.In addition,the samples prepared by the method were characterized by XRD,TEM and VSM,respectively.展开更多
Nano-MnFe2O4 particles were synthesized by co-precipitation phase inversion method and low-temperature combustion method respectively, using MnCl2, FeCl3, Mn（NO3）2, Fe（NO3）3, NaOH and C6H8O7. X-ray diffraction （...Nano-MnFe2O4 particles were synthesized by co-precipitation phase inversion method and low-temperature combustion method respectively, using MnCl2, FeCl3, Mn（NO3）2, Fe（NO3）3, NaOH and C6H8O7. X-ray diffraction （XRD）, transmission electron microscope （TEM）, Fourier transform infrared spectroscopy （FT-IR）, thermogravim-etry-differential thermal analysis （TG-DTA） and differential scanning calorimetry （DSC） were used to characterize the structure, morphology, thermal stability of MnFe2O4 and its catalytic performance to ammonium perchlorate. Results showed that single-phased and uniform spinel MnFe2O4 was obtained. The average particle size was about 30 and 20 nm. The infrared absorption peaks appeared at about 420 and 574 cm-1, and the particles were stable below 524 ℃. Using the two prepared catalysts, the higher thermal decomposition temperature of ammonium perchlorate was decreased by 77.3 and 84.9 ℃ respectively, while the apparent decomposition heat was increased by 482.5 and 574.3 J？g？1. The catalytic mechanism could be explained by the favorable electron transfer space provided by outer d orbit of transition metal ions and the high specific surface absorption effect of MnFe2O4 particles.展开更多
基金Supported by the Key Project of the National Natural Science Foundation of China（No.41530636） and the National Natural Science Foundation of China（Nos.41302184, 41471252 ）.
文摘Magnetic MnFe2O4-bentonite was synthesized by chemical co-precipitation method（CCM） and applied as catalyst in heterogeneous activation of persulfate（PS） to oxidize a target pollutant, 2,4-dichlorophenol（2,4-DCP）, in aqueous solutions. The surface morphology and structure of MnFe2On-bentonite were characterized by X-ray diffraction（XRD）, scanning electron microscope（SEM）, energy dispersive X-ray（EDX） and X-ray photoelectron spectroscopy（XPS） analyses.The catalytic activity of MnFe2O4-bentonite for 2,4-DCP degradation was evaluated considering the effects of various process parameters, such as mass ratio of MnFe2O4 to bentonite, concentration of catalyst, PS concentration, and pH. The MnFe2O4-bentonite hybrid exhibited higher catalytic activity than pure MnFe2O4. Treatment with 5 g/L MnFe2O4-bentonite at 30℃ for 240 rain oxidized 92% of 100 mg/L 2,4-DCP（70.2% mineralization）, whereas treatment with pure MnFe2O4 under the same condition oxidized only 70% of the pollutant. This result indicate the erdlanced performance of the activated PS. Moreover, MnFe2O4-bentonite exhibits stable performance with minimal loss in activity after five successive runs. Thus, MnFe2O4-bentonite could be a promising catalyst in oxidative degradation of 2,4-DCE
文摘In this article,MnFe2O4 nanocrystals were synthesized by coprecipitation at low temperature,and the effects of temperature,time and additive on crystallization and particle sizes of samples were also studied.In addition,the samples prepared by the method were characterized by XRD,TEM and VSM,respectively.
基金Supported by the National Natural Science Foundation of China （90305008, 51077072）.
文摘Nano-MnFe2O4 particles were synthesized by co-precipitation phase inversion method and low-temperature combustion method respectively, using MnCl2, FeCl3, Mn（NO3）2, Fe（NO3）3, NaOH and C6H8O7. X-ray diffraction （XRD）, transmission electron microscope （TEM）, Fourier transform infrared spectroscopy （FT-IR）, thermogravim-etry-differential thermal analysis （TG-DTA） and differential scanning calorimetry （DSC） were used to characterize the structure, morphology, thermal stability of MnFe2O4 and its catalytic performance to ammonium perchlorate. Results showed that single-phased and uniform spinel MnFe2O4 was obtained. The average particle size was about 30 and 20 nm. The infrared absorption peaks appeared at about 420 and 574 cm-1, and the particles were stable below 524 ℃. Using the two prepared catalysts, the higher thermal decomposition temperature of ammonium perchlorate was decreased by 77.3 and 84.9 ℃ respectively, while the apparent decomposition heat was increased by 482.5 and 574.3 J？g？1. The catalytic mechanism could be explained by the favorable electron transfer space provided by outer d orbit of transition metal ions and the high specific surface absorption effect of MnFe2O4 particles.
