Monocyclic Aromatics Research Articles

Role of Bifunctional Metal-Promoted Zeolitic Catalyst in Microwave-Assisted Pyrolysis of Polyethylene to Monocyclic Aromatics

Role of Bifunctional Metal-Promoted Zeolitic Catalyst in Microwave-Assisted Pyrolysis of Polyethylene to Monocyclic Aromatics

Chitosan-assisted reassembled hierarchical HZSM-5 for selective production of monocyclic aromatics in catalytic co-pyrolysis of biomass and plastic

Biomass presents significant potential as an alternative template agent for assisting zeolites in developing new pore structure during recrystallization to enhance their catalytic performance. In this study, a new hierarchical HZSM-5 was synthesized through the in-situ reassembly of alkali-treated HZSM-5 with chitosan as an assisting agent. The impact of chitosan dosage on the catalytic performance of the hierarchical HZSM-5, as well as the influences of temperature, catalyst dosage, and corn stover (CS) to high-density polyethylene (HDPE) mass ratio on the content and selectivity of monocyclic aromatic hydrocarbons (MAHs) during the catalytic co-pyrolysis process, were thoroughly investigated. The results indicated that chitosan exhibited great potential as a template in the reassembly of hierarchical HZSM-5 during NaOH treatment, promoting the formation of weak acid sites and micro-mesoporous structures. Compared to the parent HZSM-5, the chitosan-assistant reassembled hierarchical HZSM-5 significantly enhanced the production of MAHs and inhibited the formation of polycyclic aromatic hydrocarbons (PAHs). The highest carbon yield of MAHs reached 36.9 % at 550 °C with a chitosan dosage of 15 %. Furthermore, the chitosan-modified HZSM-5 notably enhanced the synergistic production of MAHs by 38.2 %, while preventing the formation of PAHs and coke. This study contributes insights into the sustainable synthesis of hierarchical HZSM-5 for improved production of high-value products in the co-pyrolysis of biomass and waste plastics.

Hierarchical HZSM-5 catalysts enhancing monocyclic aromatics selectivity in co-pyrolysis of wheat straw and polyethylene mixture

The limitation in bio-oil quality hampers its further utilization in the fuel or chemical industry. This study employed a combination of tetra propylammonium hydroxide (TPAOH) and NaOH solutions for HZSM-5 desilication to enhance the yield of monocyclic aromatic hydrocarbons in the catalytic co-pyrolysis of wheat straw with polyethylene. Results revealed hierarchical HZSM-5, prepared with equal mole concentrations of NaOH and TPAOH, exhibited optimal catalytic performance. The bio-oil from this process had an aromatic content of 72 %, with monocyclic aromatic hydrocarbons (MAHs) constituting 56.26 %. Further optimization was achieved through iron modification of hierarchical HZSM-5. The addition of 0.5 % iron-modified hierarchical HZSM-5 increased the aromatic hydrocarbons to 80.57 %, with BTX compounds (benzene, toluene, and xylene) reaching a selectivity of 61.9 %. This approach reduced polycyclic aromatic hydrocarbons (PAHs), contributing to less coke formation, presenting a promising method for high-quality bio-oil.

Reclamation of coastal marshes to croplands shifts molecular composition of soil organic matter in the Bohai Rim

AbstractReclamation of coastal marshes to croplands lost massive reserves of soil organic matter (SOM). However, it is uncertain how reclamation shifts chemical composition of SOM and its size fractions. Here, we investigated this issue at two coastal marshes (Qilihai, degradation with seasonal waterlog; Beidagang, annual long‐term waterlog) along with adjacent long‐term reclaimed croplands on the coast of the Bohai Bay, China. Three SOM fractions: coarse particulate (cPOM, >250 μm), fine particulate (fPOM, 53–250 μm), and mineral‐associated organic matter (<53 μm) were analyzed by pyrolysis‐gas chromatography–mass spectrometry. Compared with the Qilihai marsh, the Beidagang marsh had higher SOM contents and lower proportions of microbial‐derived N‐containing compounds, which was attributed to the waterlogging‐induced weaker decomposition. Reclamation decreased the SOM contents (−53.6% to −63.3%) and proportions of lignin in cPOM (−44% to −52%) at both sites. However, reclamation‐induced shifts of molecular composition of SOM between the two sites diverged. At the Qilihai site, reclamation decreased the relative abundances of N‐containing compounds (−28%) but increased the proportions of lipids (+17%) and phenolics (+40.7%) in mineral‐associated organic matter. At the Beidagang site, reclamation decreased the proportions of monocyclic aromatics (−60.3% to −70.2%), but increased the relative abundances of N‐containing compounds (+175% to +407%) in all fractions. By contrast, the molecular composition of SOM at the two croplands had covergent pattern. In conclusion, despite of marsh locations with different waterlogging conditions, long‐term reclamation of wetlands to croplands generated convergent patterns in storage and molecular composition of SOM, which was attributed to the similar cropland cultivation.

Counteractive catalytic effects of FeNi- versus Fe- and Ni- in plastic pyrolysis for advanced-quality jet fuel production

It is promising to produce jet fuel through catalytic pyrolysis of plastic to alleviate the fossil depletion and environmental pollution. Hence, it is important to improve the catalyst and catalytic parameters for the process. This study evaluated the performance of plastic pyrolysis using catalysts loaded with Fe-, Ni-, and FeNi-. The FeNi/Y (Fe and Ni loaded on Y zeolite) catalyst stood out, delivering a high oil yield rate of 64.0 wt%. The obtained oil was abundant in alkanes (38.21 area%) and monocyclic aromatics (35.40 area%) and low in alkenes (13.12 area%), which were optimal for jet fuel production. Various supports were then screened, including four zeolites (Beta zeolite, Y zeolite, Mordenite zeolite, and Zeolite Socony Mobil-5) and activated carbon, with FeNi/Y demonstrating superior performance in both oil yield and quality. Among different pyrolysis temperatures (450, 500, 550, 600, and 650 °C), 550 °C was found to be the ideal temperature for a maximum oil yield. The stable oil yield rate observed during catalyst regeneration experiments confirmed the potential of FeNi/Y for jet fuel production. The research also revealed a significant contrast in catalytic effects between FeNi- and single Fe- or Ni- catalysts. FeNi- favorably cyclized and hydrogenated alkenes, while Fe- and Ni- mainly decyclized monocyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. This difference may be attributed to their hydride ion abstraction capability, a trait absent in FeNi.

Recycling Valuable Alkylbenzenes from Polystyrene through Methanol-Assisted Depolymerization.

The vast bulk of polystyrene (PS), a major type of plastic polymers, ends up in landfills, which takes up to thousands of years to decompose in nature. Chemical recycling promises to enable lower-energy pathways and minimal environmental impacts compared with traditional incineration and mechanical recycling. Herein, we demonstrated that methanol as a hydrogen supplier assisted the depolymerization of PS (denoted as PS-MAD) into alkylbenzenes over a heterogeneous catalyst composed of Ru nanoparticles on SiO2. PS-MAD achieved a high yield of liquid products which accounted for 93.2 wt % of virgin PS at 280 °C for 6 h with the production rate of 118.1 mmolcarbon gcatal. -1 h-1. The major components were valuable alkylbenzenes (monocyclic aromatics and diphenyl alkanes), the sum of which occupied 84.3 wt % of liquid products. According to mechanistic studies, methanol decomposition dominates the hydrogen supply during PS-MAD, thereby restraining PS aromatization which generates by-products of fused polycyclic arenes and polyphenylenes.

Recycling Valuable Alkylbenzenes from Polystyrene through Methanol‐Assisted Depolymerization

AbstractThe vast bulk of polystyrene (PS), a major type of plastic polymers, ends up in landfills, which takes up to thousands of years to decompose in nature. Chemical recycling promises to enable lower‐energy pathways and minimal environmental impacts compared with traditional incineration and mechanical recycling. Herein, we demonstrated that methanol as a hydrogen supplier assisted the depolymerization of PS (denoted as PS‐MAD) into alkylbenzenes over a heterogeneous catalyst composed of Ru nanoparticles on SiO2. PS‐MAD achieved a high yield of liquid products which accounted for 93.2 wt % of virgin PS at 280 °C for 6 h with the production rate of 118.1 mmolcarbon gcatal.−1 h−1. The major components were valuable alkylbenzenes (monocyclic aromatics and diphenyl alkanes), the sum of which occupied 84.3 wt % of liquid products. According to mechanistic studies, methanol decomposition dominates the hydrogen supply during PS‐MAD, thereby restraining PS aromatization which generates by‐products of fused polycyclic arenes and polyphenylenes.

Study on H3PO4-activated carbon catalytic co-pyrolysis of bamboo and LDPE to poly-generation syngas and aromatics at low temperature

Biomass-derived carbon activated by H3PO4 was adopted to catalytic co-pyrolysis of bamboo and low-density polyethylene (LDPE) to produce syngas and aromatics on a fixed bed reactor. Effects of LDPE ratio in the feedstock, catalytic co-pyrolysis temperature and ratio of catalyst to feedstock on the yields and compositions of the products were investigated. The increase of LDPE ratio in liquid first improved and then reduced the relative content of aromatics, while it showed a positive effect on the yield and the H2/CO ratio of gas. 500℃ was an optimum temperature, under which the relative content of aromatics in liquid kept higher, meanwhile, avoided the undesirable polymerization reactions of monocyclic aromatics. At the same time, the content of H2 in gas reached a maximum (59.3%), which was in favor of poly-generation. H3PO4-activated carbon catalyst (H3PO4-ACC) with abundant functional groups on surface catalyzed cracking, hydrodeoxygenation, cyclization and aromatization reactions so as to facilitate the generation of aromatics. Non-condensable gas was dry reformed on P-ACC at the expense of CO2, CH4 and CO to generate char and H2. When the reaction condition was at a LDPE ratio of 50%, a catalyst/feedstock ratio of 2:1 and at 500℃, the relative content of aromatics in liqiud was 81.65% and the proportion of syngas component in gas was 79.73%. The volume ratio of H2/CO approached to 3:1 in gas under this condition. H3PO4-ACC catalytic co-pyrolysis of bamboo and LDPE could obtain high quality gas and liquid products at a relative low reaction temperature, which provided a new research idea on high-value application of biomass and waste plastics.

Study on ex-situ catalytic pyrolysis of poplar to produce aromatics over a dual-catalyst system of hydroxyapatite and HZSM-5

The ex-situ catalytic pyrolysis of poplar in a dual-catalyst system of hydroxyapatite (HAP) and HZSM-5 was performed using a bench-scale device to enhance the aromatics production. Results indicated that the introduction of HAP could effectively achieve the deoxygenation of macromolecular oxygenates, which were then converted into hydrocarbon precursors. The combination of HAP and HZSM-5 exceedingly promoted the production of aromatics especially monocyclic aromatics (MAHs) than single HZSM-5. The effects of operating conditions on aromatics yield and distribution were investigated. Under the catalyst layout of mode B, with the optimum conditions reaching the catalytic temperature of 500 °C, HAP to HZSM-5 ratio of 2:4, and catalyst to biomass ratio of 1:1, the maximum aromatics yield of 9.10 wt% was achieved, accompanied by the monocyclic aromatics/polycyclic aromatics ratio enhanced to 2.33. At this point, the synergistic effect for MAHs and total aromatics reached 170.09% and 214.14%, respectively. Compared to the conventional metal oxides, the HAP/HZSM-5 dual-catalyst system exhibited superior performance in aromatics production. Besides, the anti-coking capability of HZSM-5 in the dual-catalyst system was also better than that of pure HZSM-5. This research provided a new perspective for the efficient utilization of biomass energy.

Synergistic interaction between scrap tyre and plastics for the production of sulphur-free, light oil from fast co-pyrolysis

Fast co-pyrolysis offers a sustainable solution for upcycling polymer waste, including scrap tyre and plastics. Previous studies primarily focused on slow heating rates, neglecting synergistic mechanisms and sulphur transformation in co-pyrolysis with tyre. This research explored fast co-pyrolysis of scrap tyre with polypropylene (PP), low-density polyethylene (LDPE), and polystyrene (PS) to understand synergistic effects and sulphur transformation mechanisms. A pronounced synergy was observed between scrap tyre and plastics, with the nature of the synergy being plastic-type dependent. Remarkably, blending 75 wt% PS or LDPE with tyre effectively eliminated sulphur-bearing compounds in the liquid product. This reduction in sulphur content can substantially mitigate the release of hazardous materials into the environment, emphasizing the environmental significance of co-pyrolysis. The synergy between PP or LDPE and tyre amplified the production of lighter hydrocarbons, while PS's interaction led to the creation of monocyclic aromatics. These findings offer insights into the intricate chemistry of scrap tyre and plastic interactions and highlight the potential of co-pyrolysis in waste management. By converting potential pollutants into valuable products, this method can significantly reduce the release of hazardous materials into the environment.

Enhancement of aromatics and syngas production by co-pyrolysis of biomass and plastic waste using biochar-based catalysts in microwave field

In this study, O-rich biomass (bamboo) was co pyrolyzed with H-rich plastic waste (PE) based on the biochar-based catalysts to investigate the yield and quality of pyrolysis oil and syngas. Focusing on the variations of aromatics and phenolics, to reveal the synergetic mechanism between biomass and PE in microwave field. Biomass is “rich in O and lack of H″, and waste plastics are “rich in C and rich in O″ which can provide a lot of H radicals for catalytic pyrolysis of biomass, improve the quality of bio-oil. And the active factors of biomass effectively activated PE. The biochar-based catalysts further promoted deoxygenation and arylation reactions, intensifying the generation of aromatics and reducing oxygen-containing compounds (phenols, etc.). Bamboo: PE = 1: 3 catalyzed by Zr-modified biochar-based catalysts resulted in aromatics yielded as high as 74.13%, while phenols yields was only 9.39%. Incorporation of the externally H-donor PE promoted the growth of carbon chains, and the microwave field activated free radicals which facilitated the cyclization and arylation of carbon. The biochar-based catalysts also promoted the generation of high-value monocyclic aromatics by utilizing the selective ability in the microwave field. Finally, the coupled synergistic mechanism of co-pyrolysis in microwave field was proposed.

Development of a Compact Skeletal Mechanism for Thermally Cracked Hydrocarbon Fuels

ABSTRACT The construction of a compact kinetic mechanism for thermally cracked hydrocarbon fuels holds great importance for developing advanced engine with regenerative cooling. In the present study, a skeletal oxidation mechanism consisting of 104 species and 373 reactions, which can be divided into two parts, i.e. a core mechanism for pyrolysis gas, and a skeletal sub-mechanism for pyrolysis liquid, was developed by a decoupling method. The combustion process of pyrolysis gas and its pure constituents was depicted by incorporating detailed reaction pathways of H2/CO/C1-C4 molecules, and variations of hydrocarbon classes, as well as carbon number distributions were also considered by introducing eight skeletal sub-mechanisms for heavy hydrocarbons which covered chain alkanes, cycloalkanes, and monocyclic aromatics in pyrolysis liquid, thus the newly developed mechanism was suitable for thermally cracked hydrocarbon fuels over a wide range of pyrolysis temperatures. The skeletal mechanism was extensively validated by experimental data of laminar burning velocities and ignition delay times, confirming its applicability for reproducing the flame characteristics of pyrolysis gases, pyrolysis liquids, and thermally cracked fuels. Sensitivity analyses showed that laminar burning velocities of thermally cracked fuels were only affected by reactions involving small radicals when the pyrolysis temperature was lower than 600°C, while reactions involving benzene rings started to dominate the flame propagation of thermally cracked fuel at 650°C under fuel-lean, stoichiometric, and fuel-rich conditions. Reactions of small radicals and heavy hydrocarbons both affected the ignition process of thermally cracked fuels.

Catalytic co-pyrolysis of coffee grounds and polyethylene: A comparison of HZSM-5 and HY

The effects of the HZSM-5 and HY catalysts on the co-pyrolysis performance and product distribution of coffee grounds and polyethylene (CP73) were characterized via thermogravimetric analyzer with Fourier transform infrared spectroscopy and pyrolysis–gas chromatography-mass spectrometry. The addition of HZSM-5 and HY facilitated the decomposition of CP73 and reduced its residual content. HY-catalyzed CP73 (CP73/HY) exhibited the lower residual content, with a 9.09 % decrease, than did CP73 (eliminating the influence of the mixing ratio). The addition of the catalysts did not enhance the pyrolysis performance of CP73; however, an increase in the mean decomposition rate promoted its decomposition. The addition of the catalysts significantly reduced the activation energy of CP73 to varying degrees. The maximum reduction in the activation energy occurred with CP73/HY, from 218.58 kJ/mol for CP73 to 191.86 kJ/mol. The addition of HY and HZSM-5 produced up to 35.94 % and 46.43 % aromatics, respectively, relative to that of CP73. In particular, CP73/HZSM-5 generated a higher quantity of monocyclic aromatics, whereas CP73/HY produced a greater amount of alkylbenzenes than did CP73. This study provides actionable insights into the practical implementation of the catalytic co-pyrolysis of biomass and plastics.

Highly efficient production of monocyclic aromatics from catalytic co-pyrolysis of biomass and plastic with nitrogen-doped activated carbon catalyst

Highly efficient production of monocyclic aromatics from catalytic co-pyrolysis of biomass and plastic with nitrogen-doped activated carbon catalyst

Novel insight into structure and content of olefins in thermally cracked heavy oil and its saturates, aromatics, resins and asphaltenes fractions determined by 1H NMR spectroscopy

The factors leading to olefinic hydrogen signal shielding in the 1H NMR spectra of thermally cracked vacuum residue (VR) and its heavy fractions were revealed using a series of model compound systems, and the effect of olefinic hydrogen signal shielding on the determination of olefinic hydrogen content was elucidated. There were two main factors leading to the olefinic hydrogen signal shielding in the 1H NMR spectra of olefins in heavy fractions, i.e. intramolecular and intermolecular. For the olefin itself in heavy fractions, the chemical shift of the olefinic hydrogen closest to the aromatic ring was in the aromatic region rather than the olefinic region due to the π-π conjugation effect between the double bond and the intramolecular aromatic ring. Notably, the response intensity of the olefinic hydrogen signal could be weakened or even disappear due to the suppressive effect of the intermolecular aromatic structures in other polycyclic aromatic hydrocarbons (PAHs), while alkanes and monocyclic aromatics had little effect on the olefinic hydrogen signal response. Although the olefinic hydrogen signal was detected merely at about 5.30 ppm in the 1H NMR spectra of heavy fractions, these olefinic structures may be predominantly of the R─CH═CH2 type rather than the R─CH═CH─R′ type. More importantly, the measured olefinic hydrogen content of thermally cracked VR and its heavy fractions may be considerably lower than the actual content, with the measured content being only about 30–40 % of the actual content. This is mainly due to the weakening and disappearance of the olefinic hydrogen signal, coupled with the fact that the integral area of the possible olefinic hydrogen signal in the aromatic region was overlooked when calculating the total integral area of the olefinic hydrogen signal in the 1H NMR spectrum.

Catalytic pyrolysis of lignite with clay catalyst activated with spent pickling liquor

AbstractSpent pickling liquor (SPL) is an acidic waste with rich iron content from the stainless steel production industry. Reusability of SPL as a catalytic activity promoter in bentonite clay is crucial for the catalytic pyrolysis of various materials like biomass, coal, and waste plastics. For this aim, the bentonite catalyst activated with the SPL nomenclatured as SPL‐treated bentonite (SPLAB) catalyst was employed in the catalytic pyrolysis of lignite for an oil product with high yield and quality. The SPL‐treated bentonite catalytic pyrolysis oil (SPLABO) for the conditions of the final temperature of 600°C, heating rate of 10°C/min, and catalyst ratio of 15 wt% had a yield of 26.35 ± 1.14 wt% and good fuel properties in view of the higher heating value of 35.23 MJ/kg and density of 1076.4 kg/m3 at 20°C. Moreover, it has a rich chemical content by means of monocyclic aromatics and shorter chain alkanes compared with that of the thermal activated bentonite oil (TABO). Based on the chemical structure analysis results of the SPLABO and TABO comparatively, it was concluded that the SPL agent used as a catalytic activity promoter led to a significant increase in the catalytic activity of bentonite catalyst.

Green synthesis of ZSM-5 using silica fume and catalytic co-cracking of lignin and plastics for production of monocyclic aromatics

ZSM-5 with hierarchical pore structure was synthesized by a simple two-step hydrothermal crystallization from silica fume without using any organic ammonium templates. The synthesized ZSM-5 were oval shaped particles with a particle size about 2.0 μm and weak acid-dominated with proper Brønsted (B) and Lewis (L) acid sites. The ZSM-5 was used for catalytic co-cracking of n-octane and guaiacol, low-density polyethylene (LDPE) and alkali lignin (AL) to enhance the production of benzene, toluene, ethylbenzene and xylene (BTEX). The most significant synergistic effect occurred at n-octane/guaiacol at 1:1 and LDPE/AL at 1:3, under the condition, the achieved BTEX selectivity were 24% and 33% (mass) higher than the calculated values (weighted average). The highest BTEX selectivity reached 88.5%, which was 3.7% and 54.2% higher than those from individual cracking LDPE and AL. The synthesized ZSM-5 exhibited superior catalytic performance compared to the commercial ZSM-5, indicating potential application prospect.

The mycoremediation potential of the armillarioids: a comparative genomics analysis.

Genes involved in mycoremediation were identified by comparative genomics analysis in 10 armillarioid species and selected groups of white-rot Basidiomycota (14) and soft-rot Ascomycota (12) species to confine the distinctive bioremediation capabilities of the armillarioids. The genomes were explored using phylogenetic principal component analysis (pPCA), searching for genes already documented in a biocatalysis/biodegradation database. The results underlined a distinct, increased potential of aromatics-degrading genes/enzymes in armillarioids, with particular emphasis on a high copy number and diverse spectrum of benzoate 4-monooxygenase [EC:1.14.14.92] homologs. In addition, other enzymes involved in the degradation of various monocyclic aromatics were more abundant in the armillarioids than in the other white-rot basidiomycetes, and enzymes involved in the degradation of polycyclic aromatic hydrocarbons (PAHs) were more prevailing in armillarioids and other white-rot species than in soft-rot Ascomycetes. Transcriptome profiling of A. ostoyae and A. borealis isolates confirmed that several genes involved in the degradation of benzoates and other monocyclic aromatics were distinctively expressed in the wood-invading fungal mycelia. Data were consistent with armillarioid species offering a more powerful potential in degrading aromatics. Our results provide a reliable, practical solution for screening the likely fungal candidates for their full biodegradation potential, applicability, and possible specialization based on their genomics data.

Hydrocarbon selectivity enhancement through catalytic fast co-pyrolysis of almond shell and plastic blends

BackgroundThe aim of this article is to explore possible pathways for the synergistic optimization of bio-oil by the catalytic fast co-pyrolysis of almond shell (AS) and plastic residues (polyethylene, PE, and polystyrene, PS). Pyrolysis was carried out at 650 °C at a heating rate of 20 °C/ms at a residence time of 20 s. Hydrogen from the plastic promoted the decarboxylation of acids and decarbonylation of carbonyls and sugars from biomass waste.ResultsCo-pyrolysis results showed a fall in oxygen in the AS/plastics blends, whereas carbon yields increased as did the calorific value of the oil. As expected, AS/PE blends enhanced production of hydrocarbon fractions, especially olefins, with yields reaching 81.1%, whereas AS/PS blends enhanced formation of aromatic compounds. HZSM-5 assisted the increase of monocyclic aromatics content in AS/PE blends. AS/PS blends favoured the increased of aromatics (45% of total hydrocarbons for 1:2 AS/PE-HZ). For AS/PS-HZ blends toluene was enhanced as was the production of 1,3,5-cycloheptatriene.ConclusionsThese findings helped to gain a great insight into how catalytic co-fast pyrolysis of feedstocks can enhance the formation of value-added products, promoting their economic potential for agricultural exploitations.Graphical

Catalytic pyrolysis of corn stalk for the production of aromatics: The effects of wet torrefaction and Zn/Ni-HZSM-5 on pyrolysis behavior

The pyrolysis of corn stalk (CS) was carried out to investigate the effect of wet torrefaction (WT) pre-treatment and Zn/Ni-HZSM-5 on the production of bio-oil characteristics. The synergy between WT and the loaded metal catalyst was also analyzed. The oxygen content of the CS was reduced from 50.5% to 40.8% with WT, and hemicellulose was almost removed. WT pretreatment also significantly reduced the oxygenated compounds of bio-oil and increased the selectivity of phenols, aromatics, and anhydro-sugars. The addition of catalyst improved the deoxygenation, oligomerization, and aromatization during pyrolysis. The loading of Zn and Ni could optimize the pyrolysis reaction path and increased the relative content of monocyclic aromatics (MAHs) from 3.58% to 9.67% and 6.44% during the pyrolysis of CS-WT, respectively, and bimetallic catalyst further enhanced the relative content of MAHs to 11.1%. The relative content of aromatics below C9 was higher than other groups (14.8%). Thus, the WT pretreatment of raw materials and synergistic effect of catalysts can jointly optimize the biomass pyrolysis reaction.