Pyrolysis Of Waste Research Articles

Towards sustainable electronics: High-performance biodegradable polymer-based dielectric composite utilizing hydroxyapatite from cattle bone waste

Polymer-based film capacitors find widespread use in electronics and electrical systems, but the utilization of non-biodegradable dielectric materials contributes to excessive electronic waste. To address this issue, a biodegradable composite of hydroxyapatite (HAp) and poly (butylene adipate-co-terephthalate) (PBAT) was prepared and extensively characterized. HAp, as a filler, was synthesized via biomass-derived bone waste pyrolysis. The analyses confirmed successful HAp synthesis with high crystallinity and well-defined grain boundaries, which promote interfacial polarization and charge storage capability. The composite exhibited remarkable dielectric properties, with high dielectric constant, low dielectric loss, and good breakdown strength at low filler content. The PBAT/HAp-3 % composite showed significant energy storage density improvement (3.56 J/cm3), 43.55 % higher than pure PBAT (2.48 J/cm3), alongside enhanced mechanical properties and thermal stability. This study presents a cost-effective, eco-friendly route for next-generation high-performance disposable electronics.

Microwave-assisted pyrolysis of plastic waste for liquid oil production

In this work, the article presents the results of the production of fuel oil from plastic waste using microwave-assisted pyrolysis. Under the influence of microwave power, microwave absorption material, time, catalyst, polyethylene (PE), polypropylene (PP), polystyrene (PS) and mixture (34% PE + 33% PP + 33 wt% PS) were pyrolyzed to liquid oil. The results showed that with 500 g of raw plastic, 500 W microwave power, and 120 minutes, the carbon absorber accounted for 10 wt% (compared to plastic), catalysts accounted for 20 wt%, fuel efficiency reached 84% with PS and PP, 83% with PE, and 83.5% with mixed plastics. The oil obtained qualified the standards of FO No. 1 TCVN 6239:2019. The gas chromatography/mass spectroscopy GC/MS analysis (GC-MS) showed that the composition of the pyrolysis oil is mainly hydrocarbon from C7-C12.

Comparative analysis of N2 and H2 atmospheres in fast pyrolysis of mixed palm waste: Optimizing deoxygenation and hydrocarbon yield

Comparative analysis of N2 and H2 atmospheres in fast pyrolysis of mixed palm waste: Optimizing deoxygenation and hydrocarbon yield

Selective catalytic conversion of model olefin and diolefin compounds of waste plastic pyrolysis oil: Insights for light olefin production and coke minimization

The primary challenges in ex-situ catalytic pyrolysis of plastic waste to produce light olefins lie in the selective conversion of larger olefins and diolefins downstream of the pyrolyzer. Hence, the catalytic cracking mechanism of plastic pyrolysis oil was explored using an α-olefin (1-decene) and a diolefin (1,9-decadiene) model compounds over an HZSM-5 zeolite-based catalyst in a fixed-bed reactor. Key objectives were to elucidate the reaction pathways for light olefin production, aromatization, and coke formation in catalytic cracking of larger olefins and diolefins. The investigation explored the impact of HZSM-5 steam treatment severity, contact time (∼58–226 ms), and reaction temperature (250–450 °C) on product yields. The severity of steam treatment was found to increase the 1-decene isomerization rate while decreasing the cracking rate and conversion of 1-decene to C3-4 light olefins. In the catalytic cracking of 1-decene, major product types included olefins (linear and nonlinear) and a few naphthenes, while in the case of 1,9-decadiene catalytic cracking, non-linear olefins were absent, with abundant naphthenes followed by lighter diolefins and C3-5 linear olefins. Temperature and contact time variations revealed that the catalytic cracking of 1-decene initiated with double bond rearrangement isomerization, progressing to skeletal isomerization, and intensified cracking reactions producing light C3-4 olefins. Conversely, in the catalytic cracking of 1,9-decadiene, cyclization was the primary reaction pathway, followed by β-scission, resulting in lighter conjugated dienes and light linear olefins. Thermal gravimetric analysis (TGA) of spent catalysts confirmed a higher coke amount generated during 1,9-decadiene cracking compared to 1-decene cracking, indicating that diene compounds serve as precursors for significant coke formation in plastic pyrolysis oil. These insights provide valuable understanding for catalytic upgrading of pyrolysis oil from polyolefin pyrolysis.

Electric arc synthesis of titanium carbide using carbon obtained from thermal conversion of waste from the power industry

The work presents for the first time the results of obtaining titanium carbide using a vacuum-free electric arc method using various types of biocarbon obtained by classical pyrolysis of biomass waste, such as tangerine peel, pomelo peel, banana peel, pine nut shells, walnut shells. Analysis of X-ray diffraction patterns of the synthesized materials showed the repeatability of the experiment with the receipt of diffraction maxima indicating the formation of a cubic structure of titanium carbide. An analysis of the thermal oxidation of the resulting powders showed that up to a thousand degrees the process proceeds quite slowly, but with increasing temperature the oxidation rate increases significantly. It has been established that during thermal heating in an oxidizing environment, the mass of the studied titanium carbide powders obtained using various types of carbon increases, which is confirmed by thermogravimetric analysis.

Steam cracking in a semi-industrial dual fluidized bed reactor: Tackling the challenges in thermochemical recycling of plastic waste

Steam cracking is an integral process in the plastic manufacturing industry. Conventional steam crackers are tubular reactors and use fossil-based feedstocks like naphtha and LPG. This work presents steam cracking in a dual fluidized bed (DFB) reactor as an alternative for the direct steam cracking of plastic waste. Experiments were performed on a semi-industrial DFB system using naphtha, clean polyolefins, real-life plastic wastes, and a polyolefin-derived pyrolysis oil. The results show that steam cracking in a DFB is fundamentally equivalent to steam cracking in tubular reactors. Selective production of light olefins and monoaromatics was achieved within a temperature range of 700–825 °C. Naphtha yielded up to 56 % light olefins and 7 % BTXS, with ethylene and BTXS production positively correlating with cracking severity, while C3 and C4 olefins show a negative correlation. These results confirm that the established steam cracking mechanisms also apply to large-scale DFB steam crackers. The yield of light olefins is consistently obtained at approximately 52 % relative to the polyolefin content of the feedstock, regardless of the non-polyolefin content. This highlights the DFB steam cracker’s ability to produce light olefins directly from plastic waste without presorting. However, steam cracking in DFB results in significantly higher CO and CO2 yields than conventional steam cracking, especially with feedstocks containing non-polyolefins like PET and cellulose. Additionally, steam cracking of an olefin-rich pyrolysis oil yields up to 50 % light olefins with minimal coke formation, highlighting the potential in processing plastic waste pyrolysis oils without pretreatment steps such as distillation and hydrotreatment.

PROSPECTS OF THE APPLICATION OF LOW-TEMPERATURE PYROLYSIS PROCESSES FOR THE THERMAL DESTRUCTION OF HYDROCARBON-CONTAINING WASTE OF VARIOUS ORIGINS

A generalized analysis of the existing methods of utilization of hydrocarbon-containing waste of various origins and practical data on the existing experience of using low-temperature pyrolysis processes for the thermal destruction of hydrocarbon-containing municipal and oil waste are presented. A series of studies of thermochemical processes of waste destruction were conducted for both municipal solid waste and industrial waste. The common feature that unites the objects of research is their wide morphology, the presence of the predominant proportion of hydrocarbons and their derivatives. To implement the process of low-temperature pyrolysis of hydrocarbon-containing waste of various origins, a universal installation with a rotating reactor is proposed. The features of its operation, technical characteristics and advantages are presented. The prospects for further development of low-temperature pyrolysis technology for the utilization of unsorted waste groups from sorting complexes are substantiated. Bibl. 30, Fig. 2, Tab. 2.

Fe2O3, Al2O3, or sludge ash-catalyzed pyrolysis of typical 3D printing waste toward tackling plastic pollution

Catalytic pyrolysis offers a potential solution to tackling plastic pollution by transforming plastic waste into valuable chemicals. This study explored the catalytic pyrolysis of 3D printing waste (3DPW), specifically focusing on photosensitive resin waste (PRW) and polycaprolactone waste (PCLW), with Al2O3, Fe2O3, or sludge ash (SA) containing Fe/Al. The study revealed a synergistic effect between the catalyst and 3DPW, influencing the pyrolysis properties and kinetic models. The addition of Fe2O3 significantly accelerated the main degradation stages, promoting the releases of 2-Ethylacrolein (64.78 % from PRW) and 2-Oxepanone (16.45 % from PCLW), as well as decreasing the acidic products. The catalytic pyrolysis changed the valence state of Fe, with some Fe(III) shifting to Fe(II), accompanied by the release of CO2. The addition of Al2O3 or SA generated new gaseous products (e.g., 2.93 % 1,3-Pentadiene, 2-methyl-, (E)-) through volatile reforming. The joint optimization of the multi-response artificial neural network revealed PCLW/Fe2O3 between 325–399 °C (D = 0.669) as the optimal operation for achieving both minimal remaining mass and maximum decomposition rate. These findings offer actionable insights into the catalytic pyrolysis of 3DPW, promoting its efficient treatment and clean reutilization.

Probing the influence of synthesized hierarchical ZSM-5 catalyst in ex-situ catalytic conversion of real-world plastic waste into aromatic rich liquid oil

Plastic waste management has become a vitally important environmental and economic concern for researchers and technologists worldwide. Currently, catalytic pyrolysis of plastic waste emerged as a promising plastic waste management technique, further aiding the full-scale development of an alternate innovation to convert plastic waste into fuel (liquid oil) energy. Lately, zeolites have been one of the most suitable and versatile catalysts in converting plastic waste into fuel grade hydrocarbons via catalytic pyrolysis. The present work exhibits an attempt to synthesize and study the performance of a hierarchical ZSM-5 in a fixed bed reactor to convert the real-world (LDPE, HDPE, PP and PS) plastic wastes into higher quality fuel grade liquid oil. The hierarchical ZSM-5 catalyst having both mesopores and micropores (dual porosity) in its framework is synthesized by using a single organic template i.e., 10 % tetra propylammonium hydroxide (TPAOH). The catalyst performance study displays remarkable selectivity and increase in the yield of the aromatic component in the liquid oil obtained from different plastic wastes. The results indicate that presence of hierarchical catalyst has exceptionally lowered the reaction temperature in the range of 400–430 °C and increased the liquid oil yield in comparison with that of the thermal pyrolysis. Also, the obtained liquid oils have comparable fuel properties with that of kerosene and diesel.

Sustainable Energy Application of Pyrolytic Oils from Plastic Waste in Gas Turbine Engines: Performance, Environmental, and Economic Analysis

The rapid accumulation of polymer waste presents a significant environmental challenge, necessitating innovative waste management and resource recovery strategies. This study investigates the potential of chemical recycling via pyrolysis of plastic waste, specifically polystyrene (PS) and polypropylene (PP), to produce high-quality pyrolytic oils (WPPOs) for use as alternative fuels. The physicochemical properties of these oils were analyzed, and their performance in a gas turbine engine was evaluated. The results show that WPPOs increase NOx emissions by 61% for PSO and 26% for PPO, while CO emissions rise by 25% for PSO. Exhaust gas temperatures increase by 12.2% for PSO and 8.7% for PPO. Thrust-specific fuel consumption (TSFC) decreases by 13.8% for PPO, with negligible changes for PSO. The environmental-economic analysis indicates that using WPPO results in a 68.2% increase in environmental impact for PS100 and 64% for PP100, with energy emission indexes rising by 101% for PS100 and 57.8% for PP100, compared to JET A. Although WPPO reduces fuel costs by 15%, it significantly elevates emissions of CO2, CO, and NOx. This research advances the understanding of integrating waste plastic pyrolysis into energy systems, promoting a circular economy while balancing environmental challenges.

Effects of pyrolysis temperature on the photooxidation of water-soluble fraction of wheat straw biochar based on 21 ​T FT-ICR mass spectrometry

Biochar, formed through the pyrolysis or burning of organic wastes, has a complex chemical composition influenced by feedstock, pyrolysis temperature, and reaction conditions. Water-soluble, dissolved black carbon species released from biochar comprise one of the most photoreactive organic matter fractions. Photodegradation of these water-soluble species from wheat straw biochar, produced at different pyrolysis temperatures in laboratory microcosms, resulted in noticeable compositional differences. This study characterized water-soluble transformation products formed through the photodegradation of wheat straw biochar pyrolyzed at 300, 400, 500, or 600°C by electrospray ionization 21 ​T Fourier transform ion cyclotron resonance mass spectrometry (21T FT-ICR MS). We also evaluated global trends in the toxicity of these water-soluble fractions using MicroTox™ to assess the impacts of pyrolysis temperature. Additionally, we examined biochar surface morphology after photodegradation and observed minimal change after irradiation for 48 ​h, though the total yield of water-soluble biochar species varied with pyrolysis temperature. Trends in toxicity observed from MicroTox® analysis reveal that water-soluble photoproducts from biochar produced at 300°C and 900°C are nearly three times as toxic compared to dark controls. The ultrahigh resolving power of 21T FT-ICR MS allows for the separation of tens of thousands of highly oxidized, low-molecular-weight (<1 ​kDa) species, showing that photoproducts span a wider range of H/C and O/C ratios compared to their dark analogs. This study highlights the impacts of photodegradation on the molecular composition of water-soluble biochar species and underscores the influence of pyrolysis temperature on the quantity and composition of dissolved organic species.

Pyrolysis of Khat waste vs. Coal: Experimental and Aspen plus analysis

This study explores the potential of Khat waste as a biofuel through a detailed analysis of its physical properties and pyrolytic behavior, employing both laboratory and simulation techniques. Biomass, including Khat waste, is a valuable renewable energy source with potential applications in reducing waste and CO2 emissions, especially in rural areas of developing countries like Ethiopia. The physical properties of the Khat waste were thoroughly examined, including moisture content, ash, volatile matter (VM), fixed carbon (FC), and elemental composition. The apparent density of the pyrolyzed khat waste was found to be 0.9688 g/cm³. The TGA results showed a moisture loss of 6.7 %, volatile matter of 4.7 %, fixed carbon of 6.78 %, and ash content of 5.55 %. Notably, Khat waste exhibited unique thermal behavior with a downward shift in TG curves above 220 °C. DTGA identified three decomposition peaks: moisture evaporation at 100 °C, hemicellulose breakdown at 210 °C, and cellulose degradation at higher temperatures. Fourier Transform Infrared Spectroscopy (FTIR) provided insights into the functional groups present in Khat waste, including alkene functional groups and O-H bonds, which are crucial for biofuel properties. Simulation using Aspen Plus software modeled the pyrolysis process, highlighting how varying heating rates affect volatile matter and fixed carbon content. Increasing heating rates decreased volatile matter and moisture but increased fixed carbon content. These findings offer valuable insights for optimizing Khat waste as a biofuel, emphasizing the need for tailored pyrolysis conditions to enhance biofuel production efficiency.

Thermal and catalytic pyrolysis of automotive plastic wastes to diesel range fuel

This study investigated the pyrolysis of automotive plastic wastes (APW) for the production of diesel-grade oil products using a modified calcium bentonite clay catalyst. The research aimed to optimize the process for maximum oil yield and diesel range organics yield. The APW was characterized by its chemical composition and physical properties and the optimal temperature and catalyst amount were determined for maximum oil yield and diesel range hydrocarbons. The results showed that the APW contained mixed Acrylonitrile Butadiene Styrene (ABS), High/Low Density Polyethylene (H/LDPE), Polypropylene (PP), Polystrene (PS) and fiberglass, with a large quantity of volatiles and ash. The average oil yield was higher in the catalytic process compared to that in the thermal process. Generally, higher temperature above 450 °C produced waxy oil, thus lower temperature favoured more Diesel Range Organics (DRO). Both processes yield similar yields of C8–C24 DRO, and in both cases, lower temperature favoured high yield of C8-C24 hydrocarbons. The catalyst significantly increased the yield of oil, but did not significantly increase C8–C24 DRO yield. The optimal conditions for a maximum oil yield of 78.6 % and DRO yield of 79.5 % was a temperature of 416 °C and 24.3 wt% clay. Thus, the modified calcium bentonite clay can be used to improve oil yield from pyrolysis of APW. The oil produced had properties such as calorific value (49.85 MJ/kg), flash point (113 °C) and total aromatics 3.55 area%, similar to those of commercial diesel, and comprised mostly of 2,4-Dimethyl-1-heptene (25.37 ± 2.01 %) of thermal and 2, 4 – Dimethyl – 1 – heptane (23.44 ± 2.42) in the catalytic process. The study suggests further research to explore different catalysts, maximization of both DRO and gasoline range organics, recover energy from residues, and conduct techno-economic assessments for plant-scale operations. Additionally, policies on the management of end-of-life vehicles should include provisions for stripping and segregation of plastic components by accredited providers for the purpose of plastics recycling.

Design of a Thermally Resistant and Safe Door for a Medical Waste Pyrolysis Incinerator in a Green Environment

Abstract The door of a medical waste pyrolysis incinerator plays a critical role in ensuring safe and efficient operation, as it must withstand extreme conditions, including combustion temperatures ranging from 1000 °C to 1200 °C and internal pressure. This study focuses on designing a door that is not only robust and airtight but also highly resistant to these high temperatures, ensuring both operational safety and environmental protection. The design process began with a combustion chamber capacity of 0.5 m3, with the incinerator body measuring 900 mm x 900 mm x 1200 mm and the door measuring 650 mm x 650 mm. The door was fabricated using steel with a yield strength of 245 MPa, equipped with locking bolts, and sealed with high-temperature-resistant asbestos to prevent leaks. The design was initially developed using 2D AutoCAD and 3D SolidWorks software. Analytical calculations were validated through SolidWorks simulations, revealing that the stress at the critical point was 58.185 MPa, providing a safety factor of 4.2 times above the yield stress. This robust design not only enhances the durability of the incinerator door but also contributes to the overall safety and effectiveness of medical waste management, supporting broader environmental safety goals.

Biochar-based adsorption for heavy metal removal in water: a sustainable and cost-effective approach.

The increasing contamination of aquatic bodies by heavy metals poses a significant threat to environment and human health, necessitates innovative, sustainable and cost-effective remediation strategies. Due to their persistence and toxicity, heavy metals like copper (Cu), lead (Pb), mercury (Hg), and cadmium (Cd) pose severe threats, even in trace amounts. Traditional removal methods of these heavy metals, like chemical precipitation, oxidation/reduction, filtration, ion exchange, membrane separation, and adsorption, are costly, inefficient, and have drawbacks. As an efficient and low-cost adsorbent, biochar has the potential for heavy metal remediation from water. Biochar is a versatile carbonaceous material produced through pyrolysis of organic wastes, emerged as a powerful adsorbent for heavy metal removal from contaminated water. The unique property of biochar makes it an effective medium immobilizing and capturing of heavy metals like Pb, Cd, As and Hg. Various factors affect its adsorption potential and capacity. Feedstocks type, composition, activation methods, and production processes including the pyrolysis temperature, temperature rate and residence time significantly impact the efficacy of biochar. Therefore, this review has assessed, compared, and contrasted different forms of biochar along with their production methods, modification techniques and mechanisms for their potential use as an adsorbent for heavy metal removal from the contaminated water. Modified biochar offers an environmentally friendly and cost-effective solution for water purification and remediation of toxic heavy metals from water. This review highlights the biochar potential as a crucial component for future research projects focusing on water treatment technologies, providing avenues for safer and cleaner water resources.

Enhancing catalytic pyrolysis of polypropylene using mesopore-modified HZSM-5 catalysts: insights and strategies for improved performance

Designing an active, selective, and stable catalyst for catalytic polyolefin pyrolysis is crucial for enhancing energy efficiency and economic viability in chemical processes. In this study, two synthesis methods—NaOH and NaOH/CTAB treatments—were employed to modify the physicochemical properties of CBV23, CBV55, and CBV80 zeolites. The catalytic performance of both parent and modified zeolites was evaluated for polypropylene pyrolysis using a two-stage micro-pyrolyzer coupled with two-dimensional GC-FID/MS. The NaOH/CTAB treatment preserved and enhanced strong acid sites while promoting a more uniform mesopore distribution. Among the catalysts tested, the hierarchical CBV80-ZM exhibited the best performance, achieving a propylene yield of 41 wt% and total light olefin and MA yields of 92 wt%. The improved catalytic performance was attributed to optimized acidity and larger pore size, which reduced the number of weak acid sites. These findings offer valuable insights for designing tailored zeolites based on specific target products for catalytic pyrolysis of plastic waste, particularly in the production of propylene and other high-value chemicals.

Debromination of Pyrolytic oil from waste printed circuit boards by catalytic thermo chemical reactions with Ca(OH)2 and ZSM-5

The surge in Waste Electrical and Electronic Equipment (WEEE) volume presents a formidable disposal challenge. This study focused on catalytic pyrolysis of waste printed circuit boards (WPCBs) employing Ca(OH)2 alone and in conjunction with ZSM-5 as catalysts. Kinetic parameters for catalytic and non-catalytic pyrolysis were derived through thermogravimetric analysis (TGA). The Coats-Redfern method for non-catalytic pyrolysis showcased activation energies of 33.52, 405.81, and 67.96 kJ/mol in zones 1, 2, and 3, respectively with corresponding reaction orders of 0.9, 2.8, and 1.2. Introduction of Ca(OH)2 amplified activation energy and reaction order in zones 2 and 3. Subsequent incorporation of ZSM-5 with Ca(OH)2 resulted in reduced activation energy and reaction order in zone 2, while elevating them in zones 1 and 3. Validation through laboratory-scale fixed-bed reactor experiments confirmed TGA findings and unveiled that pyrolysis oil had enhanced phenolic yield because of ZSM-5 where Ca(OH)2 showcased its effectiveness in eliminating halogens.

Improving sample preparation by biochar-coated sampling tubes: proof-of-concept extraction of sex hormones from real waters

This work showcases a novel application of biochar for analytical sample treatment. The carbonaceous material, obtained by pyrolysis of orange peel waste (550°C) without any post-synthesis treatment or functionalization, was thoroughly characterized and easily immobilized on the inner wall of sampling tubes in order to perform a sort of “in-vial” solid-phase extraction (SPE). The as-obtained device was tested for the extraction of seven sexual steroids, as probe water pollutants, from tap, lake, river water and wastewater treatment plant effluent samples spiked with 0.2-5 µg L−1 of each compound. The sorption kinetics profiles showed quantitative uptake from the sample (25 mL) in 20 min contact time, followed by complete elution in pure ethanol (2 mL, 15 min), thanks to the proper balance between sorption affinity and ease of elution. Under the selected conditions, recovery was in the range 60-123 %, with good inter-day precision (RSD 10-18 %, n=3). As evidence of the excellent reproducibility, an overall RSD below 15 % was observed from inter-day inter-batch recovery tests on three individually prepared sampling tubes. The procedure, carried out on a roller mixer, allows 10 samples to be extracted simultaneously, improving the sample throughput. Moreover, reusability tests showed that the same device maintains its efficiency for 10 consecutive sorption/desorption cycles. The greenness assessment, carried out by two dedicated software, further supported the sustainability of this biochar-based sample preparation as an alternative SPE.

Catalytic Pyrolysis of Polyethylene with Microporous and Mesoporous Materials: Assessing Performance and Mechanistic Understanding.

Testing the performance for the catalytic pyrolysis of plastic waste is hampered by mass transfer limitations induced by a size mismatch between the catalyst's pores and the bulky polymer molecules. To investigate this aspect, the behavior of a series of microporous and mesoporous materials was assessed in the catalytic pyrolysis of polyethylene (PE). More specifically, a mesoporous material, namely sulfated zirconia (Zr(SO4)2) on SBA-15, was synthesized to increase the pore accessibility, which reduces mass transfer limitations and thereby enables to better assess the effect of active site density. To demonstrate this approach, mesoporous SBA-15 wascompared to microporous zeolite Y. Using the degradation temperature during thermogravimetric analysis as a measure of activity, no correlation between acidity and activity was observed for microporous zeolite Y. However, depending on the Mw of PE, the reactivity of the mesoporous catalysts increased with increasing Zr(SO4)2 weight loading, showing that utilizing a mesoporous catalyst can overcome the accessibility limitations at least partially, which was further confirmed by polymer melt infiltration and in situ X-ray diffraction. Product analysis revealed that more aromatics and coke were produced with zeolite Y. The mesoporous material remained active and structurally intact and catalyses PE degradation via acid- and radical-based pathways.

KOH etching catalyzed microwave pyrolysis of waste tires to prepare porous graphene

KOH etching catalyzed microwave pyrolysis of waste tires to prepare porous graphene