Synthesis of flower-like Co3O4–CeO2 composite oxide and its application to catalytic degradation of 1,2,4-trichlorobenzene

Lin, Shen; Su, Guoshao; Zheng, Minghui; Ji, Dekun; Jia, Meilin; Liu, Yexuan

doi:10.1016/j.apcatb.2012.05.011

Cited by 74 publications

(24 citation statements)

References 64 publications

(100 reference statements)

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“…As shown in Fig. 8(a), four characteristic peaks with three split peaks were observed when DMSO was used as the solvent, with the hyperfine constants of N = 13.91 G and g = 2.0092, being in agreement with those previously identified for DMPO-O 2 −• [51,52]. However, no DMPO-• OH signal was observed when water was used as the solvent, as shown in Fig.…”

Section: Esr Analysissupporting

confidence: 86%

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Huang¹,

Su²,

Zhang³

et al. 2013

Journal of Hazardous Materials

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h i g h l i g h t s• The NiFe 2 O 4 had the highest activity in degradation of CB-209, followed by Fe 3 O 4 .• Hydroxyl species, organic acids, PCBs and chlorobenzenes were identified as products.• Three degradation reactions and one combination reaction competitively occurred.• Hydrodechlorination of CB-209 was more favored over Fe 3 O 4 than NiFe 2 O 4 .• Oxidation reaction of CB-209 was more favored over t r a c tA series of mesoporous iron-based spinel materials were synthesized to degrade polychlorinated biphenyls (PCBs), with CB-209 being used as a model compound. The materials were characterized by X-ray powder diffraction (XRD), pore structure analysis, and X-ray photoelectron spectroscopy (XPS). A comparison of the dechlorination efficiencies (DEs) of the materials revealed that NiFe 2 O 4 had the highest DE, followed by Fe 3 O 4 . Newly produced polychlorinated biphenyls, chlorinated benzenes, hydroxyl species and organic acids were detected by gas chromatography-mass spectrometry, high performance liquid chromatography-mass spectrometry and ion chromatograph. Identification of the intermediate products indicates that three degradation pathways, hydrodechlorination, the breakage of C C bridge bond and oxidative reaction, accompanied by one combination reaction, are competitively occurring over the iron-based spinels. The relative amounts of produced three NoCB isomers were illustrated by the C Cl BDEs of CB-209 at meta-, para-and ortho-positions, and their energy gap between HOMO and LUMO. The consumption of the reactive oxygen species caused by the transformation of Fe 3 O 4 into Fe 2 O 3 in the Fe 3 O 4 reaction system, and the existence of the highly reactive O 2 −• species in the NiFe 2 O 4 reaction system, could provide a reason why the oxidation reaction was more favored over NiFe 2 O 4 than Fe 3 O 4 .

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Section: Esr Analysissupporting

confidence: 86%

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Huang¹,

Su²,

Zhang³

et al. 2013

Journal of Hazardous Materials

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“…Liu et al that the impurities of silicon and phosphorous within titanium dioxide nanoparticles change the surface charge and electrostatic interaction of nanoparticles (Liu et al, 2011). Lin et al also found that the cerium in the cobalt oxide nanomaterial could improve the mobility of the oxgyen on the surface (Lin et al, 2012). The higher reactivity of alkaline earth metal-iron composite oxides relative to iron oxide towards chlorinated organic compounds has been reported to be attributed to the Cl À /O 2À exchange (Jiang et al, 1998;Decker et al, 2002;Ma et al, 2005).…”

Section: Activity Measurementmentioning

confidence: 98%

Synthesis of hierarchical Mg-doped Fe3O4 micro/nano materials for the decomposition of hexachlorobenzene

Liu

Huang

et al. 2014

Chemosphere

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“…α-Fe 2 O 3 also promoted the catalytic activity of Ca 2 Fe 2 O 5 , owing to the interaction between supporter and active component (Tauster et al, 1981). The interaction could enhance the mobility of oxygen species in catalyst (Lin et al, 2012). However, when the molar ratio of Ca increased to 5%, the activity of the material decreased significantly, and even lower than that over pure α-Fe 2 O 3 which had lower surface area.…”

Section: Characterizations Of Ca Species-doped Fe 2 Omentioning

confidence: 90%

Thermal dechlorination of PCB-209 over Ca species-doped Fe2O3

Huang

Shi

et al. 2016

Chemosphere

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h i g h l i g h t s• 1% mol Ca species enhanced the activity of Fe 2 O 3 in the degradation of DecaCB.• Dominant Nona-MonoCB isomers were determined during hydrodechlorination reaction.• Thermodynamic and/or steric effects drive conversion.• Steric effect prevented the hydrodechlorination at ortho-positions. a r t i c l e i n f o b s t r a c tDegradation reaction of decachlorobiphenyl (PCB-209) was investigated over the synthesized Ca speciesdoped Fe 2 O 3 at 300°C. The 1%Ca-Fe 2 O 3 exhibited the highest activity among the four catalysts prepared with the pseudo-first order reaction at k obs = 0.103 min −1 . PCB-207, PCB-197, PCB-176, PCB-184, PCB-150, PCB-136, PCB-148, PCB-104, PCB-96, PCB-54, PCB-19, PCB-4 and PCB-1 were identified as the dominant isomers in their respective nonachlorobiphenyl (NonaCB) to monochlorobiphenyl (MonoCB) homologue groups. Analysis of the hydrodechlorination products indicated that dechlorination was much more favored on meta-and para-than on ortho-positions. The formation of significantly predominant NonaCB and octachlorobiphenyl (OctaCB) isomers was attributed to lower energy principles and to the 90°dihe-dral angles of two aromatic rings which prevented the hydrodechlorination at ortho-positions. When the number of chlorine atoms is not more than 7, the steric effect supports the formation of predominant PCB isomers having chlorines at four ortho-positions. During the dechlorination of tetrachlorobiphenyl (TetraCB) formed to generate monochlorobiphenyl (MonoCB) isomers, the chlorine atoms fully substituted at the ortho-positions have to be successively removed, with the first two dechlorinations preferentially occurring at the two different benzene rings. This is dissimilar to that of octachloronaphthalene in which the hydrodechlorination reaction happened preferentially at ortho-position due to the existence of steric effects. The opposite roles of the steric effect in ortho-position between PCB-209 and PCN-75 might be due to the difference of the π -conjugated plane caused by the dihedral angle of 90°and 0°of the two aromatic rings.

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Synthesis of flower-like Co3O4–CeO2 composite oxide and its application to catalytic degradation of 1,2,4-trichlorobenzene

Cited by 74 publications

References 64 publications

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Synthesis of hierarchical Mg-doped Fe3O4 micro/nano materials for the decomposition of hexachlorobenzene

Thermal dechlorination of PCB-209 over Ca species-doped Fe2O3

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