Hydrodechlorination of hexachlorobenzene in a miniaturized nano-Pd(0) reaction system combined with the simultaneous extraction of all dechlorination products

Wiltschka, Katrin; Neumann, Larissa; Werheid, Matthias; Bunge, Michael; Düring, Rolf‐Alexander; Mackenzie, Kenneth D.; Böhm, Leonard

doi:10.1016/j.apcatb.2020.119100

Cited by 22 publications

(9 citation statements)

References 44 publications

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“…8, the debromination pathway proceeded as following: BDE15 → BDE3 → DE. So, the degradation of BDE15 with OP-Pd/Fe was mainly stepwise debromination reaction, and hydrogen transfer mode was assumed as the dominated debromination mechanism, which was similar to previous studies (Liu et al 2015;Wiltschka et al 2020).…”

Section: Debrominatin Mechanism For Bde15 By Op-pd/fesupporting

confidence: 86%

Highly efficient debromination of 4,4′-dibrominated diphenyl ether by organic palygorskite–supported Pd/Fe nanoparticles

Shao

Zhang

Liu

et al. 2021

Environ Sci Pollut Res

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Organic-palygorskite (OP) supported Pd/Fe nanoparticles composite (OP-Pd/Fe) was prepared by stepwise reduction method. The removal capacity of 4,4 -dibrominated diphenyl ether (BDE15) by OP-Pd/Fe was compared with other various materials. For better understanding the possible mechanism, the synthesized and reacted OP-Pd/Fe materials were characterized by TEM, SEM, XRD, and XPS, respectively. The effects of major in uencing parameters on the degradation of BDE15 were also studied. Bene t from the synergistic effect of the carrier and bimetallic nanoparticles, BDE15 could be completely debrominated into diphenyl ether (DE) under suitable conditions. A two-stage adsorption/debromination removal mechanism was proposed. The degradation of BDE15 with OP-Pd/Fe was mainly stepwise debromination reaction, and hydrogen transfer mode was assumed as the dominated debromination mechanism. The removal process tted well to the pseudo rst-order kinetic equation. The observed rate constants increased with increasing Pd loading and OP-Pd/Fe dosage, while decreased with increasing initial BDE15 concentration, the tetrahydrofuran/water ratio, and the initial pH of the solution. The work provides a new approach for the treatment of PBDEs pollution.

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Section: Debrominatin Mechanism For Bde15 By Op-pd/fesupporting

confidence: 86%

Highly efficient debromination of 4,4′-dibrominated diphenyl ether by organic palygorskite–supported Pd/Fe nanoparticles

Shao

Zhang

Liu

et al. 2021

Environ Sci Pollut Res

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“…Samples were extracted by automated solid-phase microextraction (SPME) following previous studies (Böhm et al 2016 , 2017 ; Wiltschka et al 2020 ) with modifications. Samples and blanks were measured together with an external standard calibration under the same conditions.…”

Section: Methodsmentioning

confidence: 99%

Adsorption of the hydrophobic organic pollutant hexachlorobenzene to phyllosilicate minerals

Böhm

Grančič

Scholtzová

et al. 2022

Environ Sci Pollut Res

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Hexachlorobenzene (HCB), a representative of hydrophobic organic chemicals (HOC), belongs to the group of persistent organic pollutants (POPs) that can have harmful effects on humans and other biota. Sorption processes in soils and sediments largely determine the fate of HCB and the risks arising from the compound in the environment. In this context, especially HOC–organic matter interactions are intensively studied, whereas knowledge of HOC adsorption to mineral phases (e.g., clay minerals) is comparatively limited. In this work, we performed batch adsorption experiments of HCB on a set of twelve phyllosilicate mineral sorbents that comprised several smectites, kaolinite, hectorite, chlorite, vermiculite, and illite. The effect of charge and size of exchangeable cations on HCB adsorption was studied using the source clay montmorillonite STx-1b after treatment with nine types of alkali (M+: Li, K, Na, Rb, Cs) and alkaline earth metal cations (M2+: Mg, Ca, Sr, Ba). Molecular modeling simulations based on density functional theory (DFT) calculations to reveal the effect of different cations on the adsorption energy in a selected HCB-clay mineral system accompanied this study. Results for HCB adsorption to minerals showed a large variation of solid–liquid adsorption constants Kd over four orders of magnitude (log Kd 0.9–3.3). Experiments with cation-modified montmorillonite resulted in increasing HCB adsorption with decreasing hydrated radii of exchangeable cations (log Kd 1.3–3.8 for M+ and 1.3–1.4 for M2+). DFT calculations predicted (gas phase) adsorption energies (− 76 to − 24 kJ mol−1 for M+ and − 96 to − 71 kJ mol−1 for M2+) showing a good correlation with Kd values for M2+-modified montmorillonite, whereas a discrepancy was observed for M+-modified montmorillonite. Supported by further calculations, this indicated that the solvent effect plays a relevant role in the adsorption process. Our results provide insight into the influence of minerals on HOC adsorption using HCB as an example and support the relevance of minerals for the environmental fate of HOCs such as for long-term source/sink phenomena in soils and sediments.

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“…Additionally, less chlorinated benzenes such as tetrachlorobenzene (TeCB), trichlorobenzene (TCB), dichlorobenzene (DCB), and benzene (the parent compound) are absent in the spectra, indicating that the degradation pathway of HCB in this case is not merely the stepwise dechlorination. 51,52 In particular, the MC treatment of HCB by sulfite leads to much less accumulation of chlorinated benzenes than that by reduced iron powder (Figures S14 and S15), probably because sulfite (−0.93 V SHE ) owns much stronger reducing ability than Fe 0 (−0.44 V SHE ) does. As a reference, we also identified the occurrence of intermediates during the MC treatment of 1,2,4,5-TeCB by sulfite.…”

Section: Degradation Pathway Of Hcbmentioning

confidence: 99%

Sulfite as a Green Co-milling Agent for Mechanochemical Destruction of Polychlorinated Aromatics: Working Mechanism and Structural Dependence

et al. 2023

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Mechanochemical destruction of obsolete halogenated persistent organic chemicals (especially polychlorinated aromatics) has been documented as a safe non-combustion technology, but the smooth implementation of such a system still calls for an appropriate and sustainable co-milling agent. As an example, we show that Na 2 SO 3 as a co-milling agent not only achieves faster degradation rate for hexachlorobenzene (HCB) than calcium oxide (1.4-fold) and reduced iron powders (2.9-fold) with equal mass but also enables high dechlorination ratio (97.4%) after 4 h of milling in a planetary mill. With the input of mechanical energy, the mechanistic study suggests that sulfite salts suffer partial melt to generate SO 3 2− species on fresh surfaces, which attack HCB molecules via the one-electron-transfer mechanism. Detection on intermediates and characterization on milled samples demonstrate that HCB undergoes dechlorination, polymerization, and hydrogenation and finally converts to amorphous and graphitic carbons. Correlation analysis indicates that the degradation reactivity of a specific polychlorinated aromatic compound in such a system is strongly dependent on its molecular structure (e.g., substituent groups and degree of chlorination). This work provides a new insight for utilizing sulfite for green disposal of halogenated wastes.

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Hydrodechlorination of hexachlorobenzene in a miniaturized nano-Pd(0) reaction system combined with the simultaneous extraction of all dechlorination products

Cited by 22 publications

References 44 publications

Highly efficient debromination of 4,4′-dibrominated diphenyl ether by organic palygorskite–supported Pd/Fe nanoparticles

Highly efficient debromination of 4,4′-dibrominated diphenyl ether by organic palygorskite–supported Pd/Fe nanoparticles

Adsorption of the hydrophobic organic pollutant hexachlorobenzene to phyllosilicate minerals

Sulfite as a Green Co-milling Agent for Mechanochemical Destruction of Polychlorinated Aromatics: Working Mechanism and Structural Dependence

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