Synergetic effect of alkaline earth metal oxides and iron oxides on the degradation of hexachlorobenzene and its degradation pathway

Su, Guoshao; Liu, Yexuan; Huang, Linyan; Shi, Yanmeng; Zhang, Aiqian; Zhang, Lixia; Liu, Wenbin; Gao, Lian; Zheng, Minghui

doi:10.1016/j.chemosphere.2012.08.009

Cited by 22 publications

(19 citation statements)

References 26 publications

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“…Based on these reports, it has been speculated that the free electrons released by the transformation of Fe 3 O 4 into Fe 2 O 3 could promote the reductive hydrodechlorination of CB-209. A similar case has been reported for the degradation of hexachlorobenzene over a material containing Fe 3 O 4 [37]. [54].…”

Section: Effect Of Spinel Structure On the Degradation Pathways Of Cbsupporting

confidence: 78%

“…The reason may be that the surface reactivity of materials was not only dependent on the surface area and pore volume, but also other properties such as phase composition [19]. Similar case about the lower reactivity held by The identification of the newly formed PCB products, as listed in Table S3, indicated the occurrence of a reductive hydrodechlorination reaction during the degradation of CB-209 on the iron-based spinels [36,37]. For the degradation of CB-209 over Fe 3 O 4 , the detected hydrodechlorinated products included nonachlorobiphenyl (NoCB), octachlorobiphenyl (OcCB), heptachlorobiphenyl (HpCB), hexachlorobiphenyl (HxCB), pentachlorobiphenyl (PeCB), tetrachlorobiphenyl (TeCB), trichlorobiphenyl (TrCB), and dichlorobiphenyl (DiCB).…”

Section: Activity Testmentioning

confidence: 86%

“…Taken together, these results could provide an explanation why the oxidation reaction was favored over NiFe 2 O 4 more so than over Fe 3 O 4 , even though the XPS results showed that the amount of the reactive oxygen species was greater over Fe 3 O 4 than over NiFe 2 O 4 . The competitive coexistence of reductive hydrodechlorination and oxidation reactions has been often reported for the degradation of chlorinated aromatics over metal oxides, since lower hydrochlorinated products and oxidation products, such as phenolate and acid species, have been detected simultaneously [27,37,55]. This phenomenon might be explained by different types of catalyst active centers.…”

Section: Effect Of Spinel Structure On the Degradation Pathways Of Cbmentioning

confidence: 95%

“…In contrast, only small amount of the initially hydrodechlorinated product NoCB with CB-207 was detected in NiFe 2 O 4 systems. The amounts and varieties of PCBs formed over Fe 3 O 4 were much greater than those formed over [37], and the reason would be discussed in Section 3.5.…”

Section: Activity Testmentioning

confidence: 98%

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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: Effect Of Spinel Structure On the Degradation Pathways Of Cbsupporting

confidence: 78%

Section: Activity Testmentioning

confidence: 86%

Section: Effect Of Spinel Structure On the Degradation Pathways Of Cbmentioning

confidence: 95%

Section: Activity Testmentioning

confidence: 98%

See 2 more Smart Citations

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Huang¹,

Su²,

Zhang³

et al. 2013

Journal of Hazardous Materials

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“…Su et al [48] found that the physical mixtures of alkaline earth metal oxides (MgO, CaO, SrO, BaO) and iron oxides could effectively decompose hexachlorobenzene at 300 • C. It is presumed that the decomposition of PCP precursor itself could inhibit the formation of PCDD/Fs in the reaction system. Fig.…”

Section: Possible Mechanism Of Synergetic Inhibitionmentioning

confidence: 99%

Synergetic inhibition of PCDD/F formation from pentachlorophenol by mixtures of urea and calcium oxide

et al. 2016

Journal of Hazardous Materials

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h i g h l i g h t s• Mixed CaO/urea have a synergetic inhibition effect for PCDD/Fs formation from PCP.• 5-20% urea reaction systems obtained the better synergetic inhibition effect.• 2,3,7,8-PCDD congeners were the dominant products in eight reaction systems.• Intermediates could promote the acid-base reaction to realize synergetic inhibition. a r t i c l e i n f o b s t r a c tChlorophenols are structurally similar to PCDD/Fs and have been considered as highly potential precursors for PCDD/Fs formation. The suppressing effects of PCDD/F formation from pentachlorophenol (PCP) were investigated on various mass ratios of CaO and urea. The total concentration of 2,3,7,8-PCDD/Fs, mostly dominated by OCDD, was determined to be 48.58-10186 ng/mg in inhibitor-reaction systems, being much lower than that in blank reaction system (75654 ng/mg). Interestingly, compared with pure CaO and urea reaction system, the concentration and TEQ of formed 2,3,7,8-PCDD/Fs in mixed urea/CaO reaction system were lower, especially with 5-20% urea reaction systems being respectively at decrease by 96.5-99.4% and 99.2-99.7%. The suppression efficiency of TEQ in 5-20% urea reaction systems could be always approximately 100% under 250-350• C. These results suggested that mixed inhibitors, especially 5-20% urea inhibitors, have a synergetic inhibition effect for PCDD/Fs formation from PCP. Mixed inhibitor generated several intermediates, involving CO 2 , H 2 O, NH 3 , Ca(OH) 2 , CaCO 3 , HNCO, biuret and ammelide. The complex between PCP and Ca, N-doped species, lower chlorinated phenols and benzenediol, and organic acids were also determined. Synergetic inhibition mechanism may be attributed to accelerated facilitation of acid-base reaction and N doping. The decomposition of PCP itself also contributes to prevent PCDD/Fs formation.

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Application of Deconica castanella ligninolytic enzymatic system in the degradation of hexachlorobenzene in soil

Neto

Coelho

Ballaminut

et al. 2021

Biotech and App Biochem

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Hexachlorobenzene (HCB) is a pollutant still found in the environment despite being widely banned. Considering that basidiomycetes are useful to degrade a variety of organochlorinated pollutants, we therefore report the influence of HCB on the ligninolytic enzymatic system of Deconica castanella. The inoculum was prepared with sugarcane bagasse and soybean flour and was added in soil with and without HCB (2000 mg kg soil −1 ), 5% emulsion containing soybean oil and Tween 20 at proportion 9:1, v:v; with 70% moisture at 25 • C. Fungal biomass was quantified by widely acknowledged growth biomarker ergosterol. The extraction of the enzymatic complex was performed and laccase, Mn-dependent peroxidase (MnP), and lignin peroxidase (LiP) activities were determined. Furthermore, HCB and its metabolites were quantified by gas chromatography and chlorides by potentiometric titration. Results evidenced that HCB did not interfere in fungal growth, though the only detected enzymatic activity was laccase. MnP and Lip were not detected during D. castanella growth in soil. The peak of laccase enzymatic activity occurred in the presence of HCB. In addition, the laccase exhibited thermostability. Therefore, we hereby shed light on the role of laccase in the degradation of HCB by an efficient low-cost and environmentally safe detoxification mechanism.

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Synergetic effect of alkaline earth metal oxides and iron oxides on the degradation of hexachlorobenzene and its degradation pathway

Cited by 22 publications

References 26 publications

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Synergetic inhibition of PCDD/F formation from pentachlorophenol by mixtures of urea and calcium oxide

Application of Deconica castanella ligninolytic enzymatic system in the degradation of hexachlorobenzene in soil

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