Hierarchical FAU Zeolites Boosting the Hydrocracking of Polyolefin Waste into Liquid Fuels

ACS Sustainable Chemistry & Engineering, Год журнала: 2024, Номер 12(15), С. 6013 - 6022

Опубликована: Апрель 3, 2024

Conventional metal-zeolite catalysts struggle with hydrocracking polyolefin wastes due to a significant mismatch between the size of large polymer molecules and micropores zeolites. This severely constrains diffusion site accessibility, resulting in low efficiency. Here, we unveil simple hydrothermal treatment commercial Y zeolite that creates hierarchical (Y–H), which possesses substantial layers mesoporous nanoflakes on its surface, constructing unique pore architecture. network integrates (ca. 13 nm) medium 4 mesopores original (<1 critically without altering zeolite's topology, crystallinity, or acidity. Compared Pt/Al2O3, Y–H Pt/Al2O3 exhibit remarkable 4-fold increase activity, is attributed enhanced accessibility acid sites, providing sufficient cascade cracking space for macromolecular polyolefins be efficiently converted into small, branched alkanes. Notably, catalyst achieves an impressive 96.8% PE conversion 90.8% selectivity toward value-added gasoline diesel fuels (C5–20) within h at 280 °C. work not only demonstrates pivotal role networks but also highlights their broader applicability plastic waste upcycling.

Язык: Английский

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Photochemical upcycling and recycling of plastics: achievements and future opportunities

Green Chemistry, Год журнала: 2024, Номер 26(15), С. 8528 - 8549

Опубликована: Янв. 1, 2024

Recent developments in the photochemical upcycling and recycling of plastics.

Язык: Английский

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Supported Platinum Nanoparticles Catalyzed Carbon–Carbon Bond Cleavage of Polyolefins: Role of the Oxide Support Acidity

ACS Applied Materials & Interfaces, Год журнала: 2024, Номер 16(9), С. 11361 - 11376

Опубликована: Фев. 23, 2024

Supported platinum nanoparticle catalysts are known to convert polyolefins high-quality liquid hydrocarbons using hydrogen under relatively mild conditions. To date, few studies grafted onto various metal oxide (MxOy) supports have been undertaken understand the role of acidity support in carbon–carbon bond cleavage polyethylene consistent catalytic Specifically, two Pt/MxOy (MxOy = SrTiO3 and SiO2–Al2O3; Al 3.0 wt %, target Pt loading 2 % ∼1.5 nm), identical hydrogenolysis conditions (T 300 °C, P(H2) 170 psi, t 24 h; Mw ∼3,800 g/mol, Mn ∼1,100 Đ 3.45, Nbranch/100C 1.0), yielded a narrow distribution with molecular weights range lubricants (Mw < 600 g/mol; 400 1.5). While Pt/SrTiO3 formed saturated negligible branching, Pt/SiO2–Al2O3 partially unsaturated (<1 mol alkenes ∼4 alkyl aromatics) increased branch density (Nbranch/100C 5.5). Further investigations suggest evidence for competitive hydrocracking mechanism occurring alongside hydrogenolysis, stemming from compared Pt/SrTiO3. Additionally, products these polymer deconstruction reactions were found be independent feedstock, allowing potential upcycle polyethylenes properties into value-added product.

Язык: Английский

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Upcycling of polyethylene terephthalate (PET) plastic wastes into carbon-based nanomaterials: Current status and future perspectives

European Polymer Journal, Год журнала: 2024, Номер 215, С. 113249 - 113249

Опубликована: Июнь 21, 2024

Язык: Английский

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Chloride and Hydride Transfer as Keys to Catalytic Upcycling of Polyethylene into Liquid Alkanes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(17)

Опубликована: Март 4, 2024

Abstract Transforming polyolefin waste into liquid alkanes through tandem cracking‐alkylation reactions catalyzed by Lewis‐acid chlorides offers an efficient route for single‐step plastic upcycling. Lewis acids in dichloromethane establish a polar environment that stabilizes carbenium ion intermediates and catalyzes hydride transfer, enabling breaking of polyethylene C−C bonds forming alkylation. Here, we show selective deconstruction low‐density (LDPE) to is achieved with anhydrous aluminum chloride (AlCl 3 ) gallium (GaCl ). Already at 60 °C, complete LDPE conversion was achieved, while maintaining the selectivity gasoline‐range over 70 %. AlCl showed exceptional rate 5000 , surpassing other acid catalysts two orders magnitude. Through kinetic mechanistic studies, rates do not correlate directly intrinsic strength or steric constraints may limit polymer access sites. Instead, processes cracking alkylation are primarily governed initiation ions subsequent intermolecular transfer. Both jointly control relative alkylation, thereby determining overall selectivity.

Язык: Английский

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Chemical Upcycling of Polyolefin Plastics Using Structurally Well-defined Catalysts

JACS Au, Год журнала: 2024, Номер 4(6), С. 2081 - 2098

Опубликована: Июнь 4, 2024

Single-use polyolefins are widely used in our daily life and industrial production due to their light weight, low cost, superior stability, durability. However, the rapid accumulation of plastic waste low-profit recycling methods resulted a global crisis. Catalytic hydrogenolysis is regarded as promising technique, which can effectively selectively convert polyolefin value-added products. In this perspective, we focus on design synthesis structurally well-defined catalysts across mesoscopic, nanoscopic, atomic scales, accompanied by insights into future directions catalyst for further enhancing catalytic performance. These principles also be applied depolymerization other polymers ultimately realize chemical upcycling plastics.

Язык: Английский

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Synthesis, Characterization and Application of Biobased Unsaturated Polyester Resin Reinforced with Unmodified/Modified Biosilica Nanoparticles

Polymers, Год журнала: 2023, Номер 15(18), С. 3756 - 3756

Опубликована: Сен. 14, 2023

This paper presents sustainable technology for environmentally friendly composite production. Biobased unsaturated polyester resin (b-UPR), synthesized from waste polyethylene terephthalate (PET) glycosylate and renewable origin maleic anhydride (MAnh) propylene glycol (PG), was reinforced with unmodified vinyl-modified biosilica nanoparticles obtained rice husk. The structural morphological properties of the particles, b-UPR, as well composites, were characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), transmission (TEM) techniques. study influence modification on mechanical composites supported hardness modeling. Improvement tensile strength b-UPR-based at 2.5 wt.% addition modified vinyl silane, named “b-UPR/SiO2-V” composite, has been achieved 88% increase. thermal aging process applied to b-UPR/SiO2-V which simulates use over product’s lifetime, leads deterioration that used fillers in commercial (c-UPR). grinded artificially aged b-UPR filler c-UPR production a table top layer outstanding properties, i.e., impact resistance microhardness, fire rated V-0 category according UL-94 test. Developing are chemically sources is important aspect preserving environment existing resources extending their life cycle.

Язык: Английский

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Catalytic and non-catalytic low-pressure hydrothermal liquefaction of pinewood sawdust, polyolefin plastics and their mixtures

Journal of Cleaner Production, Год журнала: 2023, Номер 430, С. 139733 - 139733

Опубликована: Ноя. 13, 2023

Hydrothermal co-liquefaction of biomass and polyolefin plastic feedstocks offers advantage potential synergistic reaction environments for producing liquid products high fuel quality. In this present study, hydrothermal liquefaction sawdust, low-density polyethylene high-density were investigated in a batch reactor from 350 °C to 450 autogenic pressures below 30 bar. The novel low-pressure processing method was carried out with without low-cost Ni–Cu/Al2O3 bimetallic catalyst. Thermal degradation the sawdust started at °C, whereas plastics could only completely degrade which then chosen as optimum temperature. catalysed process led an increase oil yield carbon enrichment by 16.3% deoxygenation 22% deoxygenation. Furthermore, catalyst promoted formation ketones aromatic hydrocarbons, while consuming phenols furfural sawdust-derived bio-oils. For plastics, catalyst, gave slight decreases oils favour gas and/or char formation, promotion situ hydrogenation enhance yields alkanes over alkenes. Results tests showed that interactions occurred between plastics. observed synergy further presence leading dramatic produce hydrocarbon-rich fuels less than 4 wt% oxygen contents (≈90% deoxygenation). This is efficient cost-effective pathway single-loop conversion widely available into highly deoxygenated use sustainable fuels.

Язык: Английский

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Chemical upcycling of PVC-containing plastic wastes by thermal degradation and catalysis in a chlorine-rich environment

Environmental Pollution, Год журнала: 2023, Номер 342, С. 123074 - 123074

Опубликована: Дек. 2, 2023

Chlorine (Cl)-containing chemicals, including hydrogen chloride, generated during thermal degradation of PVC and corresponding mixture impede the chemical recycling polyvinyl chloride (PVC)-containing plastic wastes. While upgrading plastic-derived vapors, presence Cl-containing chemicals may deactivate catalysts. Accordingly, herein, catalytic pyrolysis vapor prepared from a PVC-containing polyolefin is performed using fixed-bed reactor comprising zeolites. Among H-forms zeolites (namely, ZSM-5, Y, β, chabazite) used in this study, higher yield gas products composed hydrocarbons with lower carbon numbers obtained H-ZSM-5, thus indicating further decomposition to C1–C4 on acid Although formation aromatic compounds better product distributions can be adjusted by modifying acidic properties via alteration Si/Al molar ratio, maximum yields (60.8%) olefins (64.7%) are achieved ratio 50. Additionally, metal ion exchange H-ZSM-5 conducted. It reveals that highest 1.74 wt% cobalt (Co)-substituted acquired selection an appropriate concentration adjustment. Nevertheless, introduction excess Co into surface decreases cracking activity, thereby implying highly distributed required achieve excellent activity. The addition also types more Lewis sites compared Bronsted selectively produced naphthenes over paraffins aromatics. Upgrading waste-derived small hydrocarbon molecules was successfully Co-substituted H-ZSM-5. proposed approach feasible process produce valuable petroleum-replacing mixed wastes, contributing closed loops for upcycling

Язык: Английский

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A Microkinetic Model for Isomerizing Ethenolysis

ACS Catalysis, Год журнала: 2024, Номер 14(8), С. 6339 - 6348

Опубликована: Апрель 10, 2024

In isomerizing ethenolysis, tandem double bond isomerization and olefin metathesis catalysts convert polyethylene ethylene coreactants into propylene. Isomerizing ethenolysis is particularly interesting among polymer upcycling strategies because of its potentially high selectivity to a specific value-added product. Following theoretical analysis by Guironnet Peters [J. Phys. Chem. 124, 3935 (2020)], Conk et al. [Science, 377, 1561 (2022)] demonstrated in experiments using an iridium pincer dehydrogenation catalyst, dimeric Pd(I) bromide second-generation Hoveyda–Grubbs catalyst. This paper compares model predictions the two-stage that accounts for initial subsequent evolution chain length distribution, we show experimental propylene generation rates are consistent with rate zeroth order concentration long ends. contrast, assumed first dependence on To understand discrepancy, developed solved microkinetic reaction. Rate parameters estimated from prior known equilibria. We find performed near conditions maximum production rate, where kinetics saturated respect both end concentrations. For chains, not preshortened steps as al., predicts lowered concentrations smaller can become inhibited pressure.

Язык: Английский

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