The Effect of Explicit Solvent on Photodegradation of Decabromodiphenyl Ether in Toluene: Insights from Theoretical Study

Fabrications, Classifications, and Environmental Impact of PCM-Incorporated Textiles: Current State and Future Outlook

Phase change materials (PCMs) are an extraordinary family of compounds that can store and release thermal energy during phase changes. In recent years, the incorporation of PCMs into textiles has attracted considerable interest, since it represents a unique way to improve the comfort and usefulness of textiles. This article examines the advancements achieved in the preparation, classifications, and environmental effects of PCM-integrated textiles, along with a roadmap for the future. Progress of different PCM has been reported including its pros and cons. In addition, fabrications of the PCM on the apparel have been highlighted. Moreover, this Review analyzed the positive environmental impact of PCM-integrated textiles including improved insulation, extended product lifespan, and energy savings along with negative effects like higher energy consumption in the manufacturing process, added chemical additives tending to have a negative impact on the environment, less disposal features textiles and many more with recent references. Moreover, the future outlook also reports more research on nanoencapsulation, making it energy efficient, ensuring affordability, and more applications in smart PCM textiles. It seeks to stimulate additional research, encourage innovation, and contribute to the creation of high-performance, energy-efficient textiles by investigating the possibilities of PCM-enhanced textiles. The future of PCM in textiles is hopeful, with continuous research and technological advances resolving the aforementioned difficulties.

Photodegradation of brominated flame retardants in polystyrene: Quantum yields, products and influencing factors

Brominated flame retardants (BFRs) are widely used as additives in plastics, textiles and electronics materials. Here, we investigated the photodegradation of four BFRs including decabromobiphenylether (BDE-209), tetrabromobipsphenol A (TBBPA), tetrabromobisphenol A-bis(2,3-dibromopropylether) (TBBPA-DBPE) and tetrabromobisphenol A bis (allyl) ether (TBBPA-BAE). Experiments were carried out in polystyrene (PS) films using monochromatic and polychromatic irradiations. For comparison, irradiations were also carried in a solvent (tetrahydrofuran: THF). Monitoring of BFR degradation was performed using bulk and surface infrared (IR) measurements, as well as by extraction and HPLC-UV. Photoproducts were characterized using HPLC-high resolution electrospray ionization mass spectrometry (HPLC-ESI-Orbitrap-MS). All four BFRs underwent photochemical transformation in THF at 290 nm with a quantum yield (Φ) ranging from 0.05 for TBBPA to 0.27 for BDE-209, indicating an increase of photoreactivity with the number of Br atoms in BFRs. On the other hand, no major difference in the Φ values was observed when BFRs were embedded in PS films (Φ: 0.82-0.89). The higher photoreactivity in PS appears to be associated with a fast oxidation of PS as revealed by infrared (IR) analysis and yellowing of the films. Interestingly, the faster the yellowing occurred, the faster the BFR degradation was inhibited due to light screening effect. Several major photoproducts were identified for TBBPA and TBBPA-DBPE. Additional photoproducts possibly arising from PS oxidation and bromination by Br^● were observed for the first time. This work provides a better understanding of the reactivity and fate of BFRs in polymers allowing for a better assessment of their environmental impacts.

Characterization and Photodegradation of Polybrominated Diphenyl Ethers in Car Seat Fabrics from End-of-Life Vehicles

In this study, we examined the photodegradation of decabromodiphenyl ether (BDE-209) on the surface of car seat covers from end-of-life vehicles (ELVs). Samples were collected at two car dismantling facilities in Sweden and cover car models from 1989 to 1998. The content of polybrominated diphenyl ethers (PBDEs) in nine real samples (fabric and polyurethane foam) was first characterized. Fabric samples that did not contain BDE-209 were then spiked with BDE-209 and irradiated in the laboratory and under sunlight. Photoproducts were identified using high performance liquid chromatography coupled to electrospray ionization mass spectrometer (HPLC-ESI-Orbitrap-MS), whereas volatile products were analyzed by gas chromatography-mass spectrometry (GC-MS). Similar photodegradation rates and oxidation products were observed in fabric samples irradiated in the laboratory and those collected from ELVs. Estimated half-life of BDE-209 on fabric inside vehicles ranged from 3 to 6 years. Thirteen major photoproducts were identified as lower brominated products, hydroxylated BDEs, brominated and hydroxylated dibenzofurans (PBDFs) and dioxins (PBDDs). Furthermore, several photoproducts were found to be transferable into water, particularly bromophenols and hydroxylated BDEs, and others into gas phase, such as bromomethanol and 1,2-dibromoethane. This should be taken into consideration for better estimating exposure to PBDEs and to develop strategies for ELV recycling.

Effect analysis of quantum chemical descriptors and substituent characteristics on Henry's law constants of polybrominated diphenyl ethers at different temperatures

Twelve substituent descriptors, 17 quantum chemical descriptors and 1/T were selected to establish a quantitative structure-property relationship (QSPR) model of Henry's law constants for 7 polybrominated diphenyl ethers (PBDEs) at five different temperatures. Then, the lgH of 202 congeners at different temperatures were predicted. The variation rule and regulating mechanism of lgH was studied from the perspectives of both quantum chemical descriptors and substituent characteristics. The R² for modeling and testing sets of the final QSPR model are 0.977 and 0.979, respectively, thus indicating good fitness and predictive ability for Henry' law constants of PBDEs at different temperatures. The favorable hydrogen binding sites are the 5,5',6,6'-positions for high substituent congeners and the O atom of the ether bond for low substituent congeners, which affects the interaction between PBDEs and water molecules. lgH is negatively and linearly correlated with 1/T, and the variation trends of lgH with temperature are primarily regulated by individual substituent characteristics, wherein: the more substituents involved, the smaller the lgH. The significant sequence for the main effect of substituent positions is para>meta>ortho, where the ortho-positions are mainly involved in second-order interaction effect (64.01%). Having two substituents in the same ring also provides a significant effect, with 81.36% of second-order interaction effects, particularly where there is an adjacent distribution (55.02%).

Efficient photocatalytic degradation of tetrabromodiphenyl ethers and simultaneous hydrogen production by TiO2-Cu2O composite films in N2 atmosphere: Influencing factors, kinetics and mechanism

TiO₂-Cu₂O photocatalyst composite film with a heterostructure was synthesized on a copper substrate for 2,2',4,4'-tetrabromodiphenyl ether (BDE47) reduction. First, Cu₂O film was synthesized by the electrochemical deposition method, and then TiO₂ was coated on the surface of the Cu₂O film. The morphology, surface chemical composition and optical characteristics of TiO₂-Cu₂O film were characterized. The degradation efficiency of BDE47 and hydrogen production by TiO₂-Cu₂O films was higher than those by pure TiO₂ or Cu₂O films. The highest BDE47 degradation efficiency of 90% and hydrogen production of 12.7mmolL_liq^-1 after 150min were achieved by 67%TiO₂-Cu₂O films. The influencing factors were investigated in terms of film component, solvent condition, and initial pH. A kinetics study demonstrated that BDE47 degradation followed a pseudo-first-order model. Photocatalytic apparent reaction rate constant of BDE47 by TiO₂-Cu₂O films was 0.0070min^-1, which was 3.3 times of that by directly photolysis process. During photocatalytic debrmination process, the photogenerated holes were reserved in the valance band of Cu₂O to oxidize methanol. Meanwhile, the partial photogenerated electrons transferred to the conduction band of TiO₂ and directly eliminated the ortho-Br of BDE47 and yielded BDE28 and BDE15. The other partial photogenerated electrons reduced protons (H⁺) to form atomic hydrogen (H°), which could substitute the para-Br of BDE47 and generated BDE17 and produce hydrogen.

A rhodium-catalyzed tandem reaction of N-sulfonyl triazoles with indoles: access to indole-substituted indanones

Rhodium(ii)-catalyzed tandem reaction of N-sulfonyl triazoles with indoles delivered structurally diverse indole-substituted indanones bearing vicinal quaternary carbon centers.

Dehalogenation of persistent halogenated organic compounds: A review of computational studies and quantitative structure-property relationships

Dehalogenation is one of the highly important degradation reactions for halogenated organic compounds (HOCs) in the environment, which is also being developed as a potential type of the remediation technologies. In combination with the experimental results, intensive efforts have recently been devoted to the development of efficient theoretical methodologies (e.g. multi-scale simulation) to investigate the mechanisms for dehalogenation of HOCs. This review summarizes the structural characteristics of neutral molecules, anionic species and excited states of HOCs as well as their adsorption behavior on the surface of graphene and the Fe cluster. It discusses the key physiochemical properties (e.g. frontier orbital energies and thermodynamic properties) calculated at various levels of theory (e.g. semiempirical, ab initio, density functional theory (DFT) and the periodic DFT) as well as their connections to the reactivity and reaction pathway for the dehalogenation. This paper also reviews the advances in the linear and nonlinear quantitative structure-property relationship models for the dehalogenation kinetics of HOCs and in the mathematical modeling of the dehalogenation processes. Furthermore, prospects of further expansion and exploration of the current research fields are described in this article.