Chemical Recycling of Polystyrene to Valuable Chemicals via Selective Acid-Catalyzed Aerobic Oxidation under Visible Light

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(14), P. 6532 - 6542

Published: March 30, 2022

Chemical recycling is one of the most promising technologies that could contribute to circular economy targets by providing solutions plastic waste; however, it still at an early stage development. In this work, we describe first light-driven, acid-catalyzed protocol for chemical polystyrene waste valuable chemicals under 1 bar O2. Requiring no photosensitizers and only mild reaction conditions, operationally simple has also been demonstrated in a flow system. Electron paramagnetic resonance (EPR) investigations density functional theory (DFT) calculations indicate singlet oxygen involved as reactive species degradation process, which abstracts hydrogen atom from tertiary C–H bond, leading hydroperoxidation subsequent C–C bond cracking events via radical process. Notably, our study indicates adduct acid catalyst might be formed situ, act photosensitizer initiate formation oxygen. addition, oxidized polymer may play role production light.

Language: Английский

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Singlet oxygen: Properties, generation, detection, and environmental applications

Journal of Hazardous Materials, Journal Year: 2023, Volume and Issue: 461, P. 132538 - 132538

Published: Sept. 13, 2023

Language: Английский

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Photocatalytic O2 activation and reactive oxygen species evolution by surface B-N bond for organic pollutants degradation

Applied Catalysis B Environment and Energy, Journal Year: 2022, Volume and Issue: 310, P. 121329 - 121329

Published: March 19, 2022

Language: Английский

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Photodegradation of organic micropollutants in aquatic environment: Importance, factors and processes

Water Research, Journal Year: 2022, Volume and Issue: 231, P. 118236 - 118236

Published: Feb. 26, 2022

Language: Английский

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Dual Activation of Molecular Oxygen and Surface Lattice Oxygen in Single Atom Cu₁/TiO₂ Catalyst for CO Oxidation

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(48)

Published: Oct. 5, 2022

The in-depth mechanism on the simultaneous activation of O2 and surface lattice O2- one active metallic site has not been elucidated yet. Herein, we report a strategy for construction abundant oxygen sites by rational design Cu1 /TiO2 single atom catalysts (SACs). charge transfer between isolated Cu TiO2 support generates CuI 2-coordinated Olat in -O-Ti hybridization structure, which facilitates chemisorption molecules. Simultaneously, induced distortion activate adjacent , achieving dual . switches CO oxidation from Eley-Rideal (80 °C) to Mars-van Krevelen route (200 with increase reaction temperature. can modulating electron properties SACs boost heterogeneous catalytic activity.

Language: Английский

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Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2021

Photochemical & Photobiological Sciences, Journal Year: 2022, Volume and Issue: 21(3), P. 275 - 301

Published: Feb. 21, 2022

Abstract The Environmental Effects Assessment Panel of the Montreal Protocol under United Nations Environment Programme evaluates effects on environment and human health that arise from changes in stratospheric ozone layer concomitant variations ultraviolet (UV) radiation at Earth’s surface. current update is based scientific advances have accumulated since our last assessment (Photochem Photobiol Sci 20(1):1–67, 2021). We also discuss how climate change affects depletion radiation, change. resulting interlinking depletion, UV are assessed terms air quality, carbon sinks, ecosystems, health, natural synthetic materials. further highlight potential impacts biosphere extreme events occurring with increasing frequency as a consequence These other interactive examined respect to benefits its Amendments providing life Earth by controlling production various substances contribute both

Language: Английский

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Comparing Photoactivities of Dissolved Organic Matter Released from Rice Straw-Pyrolyzed Biochar and Composted Rice Straw

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(4), P. 2803 - 2815

Published: Jan. 28, 2022

Here, we systematically compared the photoactivity and photobleaching behavior between dissolved black carbon (DBC) from rice straw biochar leached organic (LDOC) compost using complementary techniques. The Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis showed that DBC was dominated by polycyclic aromatic (55.1%) tannin-like molecules (24.1%), while LDOC lignin-like (58.9%) (19.7%). Under simulated sunlight conditions, had much higher apparent quantum yields for 3DOM* 1O2 but lower •OH than LDOC. After a 168 h irradiation, total number of formulas identified FT-ICR MS decreased 40.1% with concurrent increases in O/C H/C ratios also decreases double bond equivalence minus oxygen (DBE – O) average molecular weight gel permeation chromatography. However, despite large UVA254 DOC, only 12.0% nearly unchanged ratio, DBE O values, distribution, benzenepolycarboxylic condensation (BACon) index regardless percentage condensed (ConAC %). Compared LDOC, photolysis less oxidative destructive mainly via breakup small portion highly rings, probably accompanied photodecarboxylation.

Language: Английский

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Unveiling singlet oxygen spin trapping in catalytic oxidation processes using in situ kinetic EPR analysis

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(30)

Published: July 17, 2023

Singlet oxygen ( 1 O 2 ) plays a pivotal role in numerous catalytic oxidation processes utilized water purification and chemical synthesis. The spin-trapping method based on electron paramagnetic resonance (EPR) analysis is commonly employed for detection. However, it often limited to time-independent acquisition. Recent studies have raised questions about the reliability of trapper, 2,2,6,6-tetramethylpiperidine (TEMP), various systems. In this study, we introduce comprehensive, kinetic examination monitor process EPR analysis. intensity trapping product was used as quantitative measurement evaluate concentration aqueous This situ study successfully applied classical photocatalytic system with exceptional accuracy. Furthermore, demonstrated feasibility our approach more intricate -driven decontamination elucidated molecular mechanism direct TEMP oxidation. can avoid false-positive results associated conventional 2D detection techniques, provide insights into reaction mechanisms -dominated processes. work underscores necessity analysis, presenting an avenue comprehensive exploration governing

Language: Английский

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Dissolved Organic Matter Photoreactivity Is Determined by Its Optical Properties, Redox Activity, and Molecular Composition

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(16), P. 6703 - 6711

Published: April 11, 2023

Predicting the formation of photochemically produced reactive intermediates (PPRI) during irradiation dissolved organic matter (DOM) has remained challenging given complex nature this material and differences in PPRI mechanisms. We investigate role DOM composition photoreactivity using 48 samples that span range freshwater systems wastewater. relate quantum yields for excited triplet-state (fTMP), singlet oxygen (Φ1O2), hydroxylating species (Φ•OH) to determined spectroscopy, Fourier-transform ion cyclotron resonance mass spectrometry, electron-donating capacity (EDC). fTMP Φ1O2 follow similar trends are correlated with bulk properties derived from UV–vis spectra EDC. In contrast, no individual property can be used predict Φ•OH. At molecular level, subset is positively both Φ•OH EDC distinct formulas related Φ1O2, demonstrating •OH 1O2 formed different fractions. Multiple linear regressions each parameters multiple techniques, complementary methods ideal characterizing because technique only a DOM.

Language: Английский

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Micropollutants characteristics, fate, and sustainable removal technologies for landfill leachate: A technical perspective

Journal of Water Process Engineering, Journal Year: 2023, Volume and Issue: 53, P. 103649 - 103649

Published: March 15, 2023

Language: Английский

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