Effects analysis of substituent characteristics and solvents on the photodegradation of polybrominated diphenyl ethers

Jiang, Long; Qiu, Youli; Yu, Lie

doi:10.1016/j.chemosphere.2017.07.063

Cited by 9 publications

(5 citation statements)

References 35 publications

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“…This theoretical calculation result coincides with the results of their inhibition effects on the photodegradation of NBFRs. The ΔG6 values of NBFRs in n-hexane were negative, indicating the photodegradation of NBFRs in n-hexane was spontaneous, which can be explained from two aspects: On the one hand, the reaction is affected by the electron ionization ability of ground state NBFRs molecules [ 52 ]. The vertical ionization energy of different ground state NBFRs molecules is different.…”

Section: Resultsmentioning

confidence: 99%

Photodegradation Kinetics and Solvent Effect of New Brominated Flame Retardants (NBFRS) in Liquid Medium

Jin

et al. 2022

IJERPH

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The photolysis of four typical NBFRs, hexabromobenzene (HBB), pentabromotoluene (PBT), pentabromobenzyl acrylateare (PBBA) and pentabromoethylbenzene (PBEB), were explored under different irradiation light wavelengths, initial concentrations and organic solvents. Density functional theory was used for chemical calculation to explore the internal mechanism of solvent effect. All degradation kinetics conformed to the first-order kinetic model. Under different irradiation light wavelengths, the degradation rates were in the following order: 180~400 nm (0.1702~0.3008 min−1) > 334~365 nm (0.0265~0.0433 min−1) > 400~700 nm (0.0058~0.0099 min−1). When the initial concentration varied from 0.25 mg/L to 1 mg/L, the degradation rate decreased from 0.0379~0.0784 min−1 to 0.0265~0.0433 min−1 under 334~365 nm irradiation, which might be attributed to the reduction in light energy received per unit area and competition from intermediate metabolites. In different organic solvents, the degradation rates were in the order of acetone (0.1702~0.3008 min−1) > toluene (0.0408~0.0534 min−1) > n-hexane (0.0124~0.0299 min−1). Quantum chemical calculation and analysis showed that the energy change in electron transfer between solvent and NBFRs was the key factor to solvent effect in the degradation of NBFRs. The active sites and degradation pathways of NBFRs were also speculated, the nucleophilic reaction of the Br atom on a benzene ring was the main process of photodegradation and it was preferential to remove the bromine and then the ethyl group on the benzene ring. Our research will be helpful in predicting and evaluating their photochemical behavior in different environment conditions.

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Section: Resultsmentioning

confidence: 99%

Photodegradation Kinetics and Solvent Effect of New Brominated Flame Retardants (NBFRS) in Liquid Medium

Jin

et al. 2022

IJERPH

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“…The UV spectral information of TCPP and TCPP–OH in hydrogen peroxide solvent that generated hydroxyl radicals was calculated using the PCM based on the self-consistent reaction field (SCRF) theory at B3LYP/6–31 g (d) basis set level. The information from the UV spectrum was used to analyze the enhancement of photodegradation under the solvation effect of OPFRs and their derivatives [ 24 , 25 ]. The Gibbs free energy (ΔG) and reaction energy barrier (ΔE) of OPFRs and their derivative molecules in biodegradation and photodegradation reactions at B3LYP/6–31 g (d) basis set level were computed, as shown in Formulas (1) and (2).…”

Section: Methodsmentioning

confidence: 99%

“…The energy barrier of the biodegradation reaction of TCPP and TCPP-OH were calculated and marked for each step in the degradation reaction, as shown in Figure 3. As the reaction energy barrier lowers, the probability of the biodegradation reaction increased [24]. As seen in Figure 3, different side chains of TCPP and TCPP-OH were cleaved to generate product I.…”

Section: Mechanistic Analysis For the Enhancement Of Biodegradation Fmentioning

confidence: 99%

“…The energy required for the first excited state transition of OPFRs from the UV spectrum was used to characterize the photodegradation ability of these molecules. As energy decreases, the photodegradation efficiency increases [24]. The energies required for the first excited state transition of 22 OPFRs from the UV spectrum are shown in Table 1.…”

Section: Calculation Of Photodegradation and Functional Properties Ofmentioning

confidence: 99%

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Enhanced Biodegradation/Photodegradation of Organophosphorus Fire Retardant Using an Integrated Method of Modified Pharmacophore Model with Molecular Dynamics and Polarizable Continuum Model

Yang

Liu

2020

Polymers

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A comprehensive 3D-quantitative structure–activity relationship (QSAR) pharmacophore model was constructed using the values of comprehensive biodegradation/photodegradation effects of 17 organophosphorus flame retardants (OPFRs) evaluated by a normalization method to modify OPFRs with high biodegradation/photodegradation, taking tris(chloro-isopropyl) phosphate (TCPP), tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propyl) phosphate (TCIPP)—which occur frequently in the environment, and are the most difficult to degrade as target molecules. OPFR-derivative molecules TCPP–OH shows the highest improvement in biodegradation and photodegradation (55.48% and 46.37%, respectively). On simulating the biodegradation path and photodegradation path, it is found that the energy barrier of TCPP–OH for phosphate bond cleavage is reduced by 15.73% and 52.52% compared to TCPP after modification, respectively. Finally, in order to further significantly improve its biodegradability and photodegradation, the efficiency enhancement in the biodegradation and photodegradation of TCPP–OH are analyzed under the simulated environment by molecular dynamics and polarizable continuum model, respectively. The results of molecular dynamics show that the biodegradation efficiency of the TCPP–OH increased by 75.52% compared to TCPP. The UV spectral transition energy (4.07 eV) of TCPP–OH under the influence of hydrogen peroxide solvation effect is 44.23% lower than the actual transition energy (7.29 eV) of TCPP.

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“…(1) and (2) respectively. In addition, the UV spectra of the PAE derivatives in six different organic solvents were calculated via the polarizable continuum model [29] at the B3LYP/6-31G(d) level. The six solvents were methanol, ethanol, 1-butanol, benzene, carbon tetrachloride, and diethyl ether.…”

Section: Uv Spectra and Quantum Chemical Calculationsmentioning

confidence: 99%

High Ultraviolet Sensitivity of Phthalic Acid Esters with Environmental Friendliness after Modification through Pharmacophore Modeling Associated with the Solvation Effect

Qiu¹,

Zhang²,

Liu³

2020

Pol. J. Environ. Stud.

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We established three-dimensional quantitative structure-activity relationship (3D QSAR) pharmacophore models of ultraviolet (UV) absorption intensities for phthalic acid esters (PAEs). Substituent positions were obtained using the optimum pharmacophore model, and hydrophobic groups were used to generate PAE derivatives from the priority pollutants. The UV spectra of the PAE derivatives were calculated using the same method, and were used to screen for PAE derivatives with greatly enhanced UV absorption intensities. The derivatization and solvation effects on identification of PAEs and derivatives were considered. The results showed that the Hypo1 pharmacophore model had good predictive abilities and there were 14 PAE derivatives generated. The maximum UV absorption intensities of three PAE derivatives were 121.85%, 105.20%, and 191.11% respectively, higher than those of the corresponding original PAEs. Analysis of the solvation effect showed that the UV peaks red shifted, and the degree of red shift increased with increasing solvent polarity. The minimum differential wave numbers of the UV peaks after PAE derivatization and solvation were higher than the minimum resolution of the UV spectrometer (0.1 nm). A two-dimensional QSAR analysis of the enhancement mechanism can reveal the derivatization and solvation enhancement. The logK ow values of DNOP derivatives were predicted to lower by 25.55%-34.12%.

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Effects analysis of substituent characteristics and solvents on the photodegradation of polybrominated diphenyl ethers

Cited by 9 publications

References 35 publications

Photodegradation Kinetics and Solvent Effect of New Brominated Flame Retardants (NBFRS) in Liquid Medium

Photodegradation Kinetics and Solvent Effect of New Brominated Flame Retardants (NBFRS) in Liquid Medium

Enhanced Biodegradation/Photodegradation of Organophosphorus Fire Retardant Using an Integrated Method of Modified Pharmacophore Model with Molecular Dynamics and Polarizable Continuum Model

High Ultraviolet Sensitivity of Phthalic Acid Esters with Environmental Friendliness after Modification through Pharmacophore Modeling Associated with the Solvation Effect

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