Pyrolysis of banana leaves biomass: Physico-chemical characterization, thermal decomposition behavior, kinetic and thermodynamic analyses

Lignin from Plant-Based Agro-Industrial Biowastes: From Extraction to Sustainable Applications

Lignin, the most abundant aromatic polymer in nature, plays a critical role in lignocellulosic biomasses by providing structural support. However, its presence complicates the industrial exploitation of these materials for biofuels, paper production and other high-value compounds. Annually, the industrial extraction of lignin reaches an estimated 225 million tons, yet only a fraction is recovered for reuse, with most incinerated as low-value fuel. The growing interest in lignin potential has sparked research into sustainable recovery methods from lignocellulosic agro-industrial wastes. This review examines the chemical, physical and physicochemical processes for isolating lignin, focusing on innovative, sustainable technologies that align with the principles of a circular economy. Key challenges include lignin structural complexity and heterogeneity, which hinder its efficient extraction and application. Nonetheless, its properties such as high thermal stability, biodegradability and abundant carbon content place lignin as a promising material for diverse industrial applications, including chemical synthesis and energy generation. A structured analysis of advancements in lignin extraction, characterization and valorization offers insights into transforming this undervalued by-product into a vital resource, reducing reliance on non-renewable materials while addressing environmental sustainability.

Critical insights into ensemble learning with decision trees for the prediction of biochar yield and higher heating value from pyrolysis of biomass

Pyrolysis is an efficient thermochemical conversion process, but accurate prediction of yield and properties of biochar presents a significant challenge. Three prominent ensemble learning methods, viz. Random Forest (RF), eXtreme Gradient Boosting (XGB), and Adaptive Boosting (AdaBoost) were utilized to develop models to predict yield and higher heating value (HHV) of biochar. Dataset comprising 423 observations from 44 different biomasses was curated from peer-reviewed journals for predicting biochar yield. RF regressor achieved a test R2 of 0.86 for biochar yield, while XGB regressor achieved a test R2 of 0.87 for biochar HHV prediction. The SHapley Additive exPlanations (SHAP) analysis was conducted to assess influence of each feature on the model's output. Pyrolysis temperature and ash content of biomass were identified as the most influential features for the prediction of both yield and HHV of biochar. The partial dependence plots (PDPs) revealed nonlinear relationships, interpreting how the model formulates its predictions.

An eco-friendly enzymatic treatment to prepare spinnable banana fibers as an alternative to cotton for textile applications

Banana fibers are a sustainable material with natural mechanical strength and antibacterial properties. These fibers are extracted from the large amount of waste produced by banana pseudo stems annually. However, despite their numerous advantages, their stiffness and rough texture impede their full use in the textile. This research investigates the degumming treatment of banana fibers using enzyme combination and chemical methods to achieve spinnable soft banana fibers. An L9 orthogonal array was used in a Taguchi design of the experiment to optimize the process parameters. For enzyme combination degumming, the experimental setup comprised different quantities of hemicellulase, laccase, amylase, and pectinase; for chemical degumming, varied amounts of sodium hydroxide (NaOH) were used. The results indicate that enzyme-based degumming procedures produce better results than chemical treatments. Optimum enzyme combinations for various fiber qualities were found using the Taguchi design of experiments. These combinations included Hemicellulase 5 %, Laccase 5 %, Amylase 3 %, and Hemicellulase 5 %, Laccase 3 %, Pectinase 5 %. Without degrading the cellulose structure, these ideal enzyme combinations produced fibers with lower lignin content and higher cellulose percentages, moisture content, and tenacity values. By determining the most efficient enzyme combinations and their effects on fiber qualities, the study offers sustainable fiber processing methods for textile grade banana fiber.

Municipal Solid and Plastic Waste Co-pyrolysis Towards Sustainable Renewable Fuel and Carbon Materials: A Comprehensive Review

The substantial rise in global energy demand, propelled by industrial expansion, population growth, and transportation needs, poses a formidable challenge. The concurrent urbanization places pressure on the disposal of solid municipal solid waste and the management of plastic waste. Addressing the global waste crisis requires innovative and sustainable garbage disposal solutions with an environmentally friendly approach. This review tackles the challenges of worldwide waste management, focusing on renewable and sustainable fuels and waste recycling through the exploration of co-pyrolysis as an innovative method. It explores the characteristics and environmental impact of municipal solid waste (MSW) and plastic waste (PW), delving into pyrolysis fundamentals, processes, and challenges. The primary emphasis is on co-pyrolysis, elucidating its integration of municipal and plastic waste, synergistic effects, and advantages. The manuscript thoroughly analyzes reaction kinetics, thermodynamics, and the feasibility of co-pyrolysis for energy recovery. It also delves into the synthesis of renewable fuels and valuable chemical intermediates, considering optimization of product distribution. Environmental and economic sustainability aspects, including impact assessment, greenhouse gas emissions, life cycle analysis, and cost analysis of co-pyrolysis processes, are comprehensively investigated. The review underscores the economic benefits of renewable fuel and chemical materials synthesis. The conclusion addresses challenges, proposes future directions, outlines limitations, technical challenges, environmental considerations, and recommends further exploration and integration with other waste management techniques. The manuscript emphasizes the ongoing importance of research in this critical field, aiming to contribute to the development of effective solutions for the escalating global waste management crisis.

Kinetic analysis of slow pyrolysis of oily sludge at medium temperature (350 ℃-650 ℃) and the effects of heating rate on pyrolysis

ABSTRACTPyrolysis is an effective way for the harmless treatment of oily sludge. The composition, physicochemical properties, and pyrolysis of oily sludge were experimentally studied in the present study. The Starink and Coats-Redfern methods were used to analyze the pyrolysis kinetics of oily sludge. Pyrolysis of oily sludge is divided into four stages: water evaporation stage, light component evaporation stage, heavy component pyrolysis stage, and final pyrolysis stage. The light component evaporation and heavy component pyrolysis stages are the main stages of medium-temperature pyrolysis. The pyrolysis characteristic parameters under heating rates of 10, 20, 30, and 40 K/min were obtained, and the effects of heating rates on the pyrolysis characteristics of oily sludge were discussed. The results show that with the increase in heating rate, the temperature range of each stage expands, and the temperature of the pyrolysis peaks also increases, with an average increase of 14.88%. The activation energies of the main pyrolysis stages obtained by the Starink method and Coats-Redfern method are consistent. In the light component evaporation stage, the activation energies obtained by the two methods are 61.93kJ/mol and 68.6kJ/mol, while the activation energies are 294.88kJ/mol and 367kJ/mol in the heavy component pyrolysis stage. The pyrolysis mechanism functions are obtained, and the pyrolysis kinetic equations under 10, 20, 30, and 40 K/min were constructed and validated by comparison with the results of the calculated properties and experimental measurement. This study can provide a better insight into the heat and mass transfer processes of oily sludge in pyrolysis reactors for further development and optimization.

Exploring Corymbia torelliana hydrochar combustion kinetics through thermogravimetric analysis, peak deconvolution and reaction profile modelling

This study aims to conduct an applied and innovative investigation to enhance the energy quality of wood residues through hydrothermal carbonization pretreatment. For this purpose, the treatment was carried out at three different temperatures: 180, 220, and 240 °C under autogenous pressure. The in natura material and the hydrochars were characterized, and thermogravimetric analyses were performed in an O2 atmosphere with heating rates of 2.5, 5, 10, and 20 °C min-1. The global activation energy for natura biomass combustion was determined to be 112.49 kJ.mol-1. On the other hand, the hydrothermal carbonization process promoted a reduction in this value for the 94.85 kJ.mol-1. The conversion function for the in natura biomass was characterized as 1 - α , order 1, while the hydrochars was 2(1-α) [-ln(1-α)] (1⁄2), Avrami-Erofe'ev I. Triple kinetic parameters were ascertained, and the conversion curves along with their respective derivatives were modeled, exhibiting minimal deviations between theoretical and experimental data. This facilitated the mathematical representation of the reaction processes and allowed for a comprehensive comparison of the results.

From biomass to Energy: Investigating Chlorella pyrenoidosa's potential for fuel and carbon materials

This study investigated the bioenergy potential of Chlorella pyrenoidosa (CP) for use as fuel and carbon material through chemical and thermal characterization. The thermo-kinetic characteristics of Chlorella pyrenoidosa were assessed using isoconversional, linear regression, and non-linear regression approaches. The physicochemical analysis revealed high carbon (53.1 %), volatile (69.35 %), and low moisture (2.19 %), ash content (3.42 %). The results indicated that the non-linear model fitting method was the most accurate with the approximated activation energy (Eα) and pre-exponential Arrhenius constant (Ln A) were 124.92 ± 2.74 kJ/mol and 23.38 ± 4.63 min-1, respectively. Additionally, the inclusion of sodium bicarbonate resulted in a significant increase in BET surface area. FTIR analysis revealed several functional groups beneficial for carbon material, while XRD analysis showed a broad peak correlated with an amorphous structure. This study highlighted the potential of Chlorella pyrenoidosa biomass for various applications, including carbon material and renewable fuel.

The Fabrication, Drug Loading, and Release Behavior of Porous Mannitol

Porous materials are widely used as an effective strategy for the solubilization of insoluble drugs. In order to improve the solubility and bioavailability of low water-solubility drugs, it is necessary to prepare porous materials. Mannitol is one of the most popular excipients in food and drug formulations. In this study, porous mannitol was investigated as a drug carrier for low water solubility drugs. Its fabrication, drug loading, and drug release mechanisms were investigated. Porous mannitol was fabricated using the co-spray-antisolvent process and utilizing polyvinylpyrrolidone K30 (PVP K30) as the template agent. Porous mannitol particles were prepared by changing the proportion of the template agent, spraying the particles with mannitol, and eluting with ethanol in order to regulate their pore structure. In subsequent studies, porous mannitol morphology and characteristics were determined systematically. Furthermore, curcumin and ibuprofen, two poorly water-soluble drugs, were loaded into porous mannitol, and their release profiles were analyzed. The results of the study indicated that porous mannitol can be prepared using PVP K30 as a template and that the amount of template agent can be adjusted in order to control the structure of the porous mannitol. When the template agent was added in amounts of 1%, 3%, and 5%, the mannitol pore size increased by 167.80%, 95.16%, and 163.98%, respectively, compared to raw mannitol. Molecular docking revealed that mannitol and drugs are adsorbents and adhere to each other by force interaction. The cumulative dissolution of curcumin and ibuprofen-loaded porous mannitol reached 69% and 70%, respectively. The release mechanism of curcumin and ibuprofen from drug-loaded mannitol was suitable for the Korsmeyer-Peppas kinetic model. In summary, the co-spray-antisolvent method proved effective in fabricating porous materials rapidly, and porous mannitol had a remarkable effect on drug solubilization. The results obtained are conducive to the development of porous materials.

Navigating Pyrolysis Implementation-A Tutorial Review on Consideration Factors and Thermochemical Operating Methods for Biomass Conversion

Pyrolysis and related thermal conversion processes have shown increased research momentum in recent decades. Understanding the underlying thermal conversion process principles alongside the associated/exhibited operational challenges that are specific to biomass types is crucial for beginners in this research area. From an extensive literature search, the authors are convinced that a tutorial review that guides beginners particularly towards pyrolysis implementation, from different biomasses to the thermal conversion process and conditions, is scarce. An effective understanding of pre-to-main pyrolysis stages, alongside corresponding standard methodologies, would help beginners discuss anticipated results. To support the existing information, therefore, this review sought to seek how to navigate pyrolysis implementation, specifically considering factors and thermochemical operating methods for biomass conversion, drawing the ideas from: (a) the evolving nature of the thermal conversion process; (b) the potential inter-relatedness between individual components affecting pyrolysis-based research; (c) pre- to post-pyrolysis' engagement strategies; (d) potential feedstock employed in the thermal conversion processes; (e) the major pre-treatment strategies applied to feedstocks; (f) system performance considerations between pyrolysis reactors; and (g) differentiating between the reactor and operation parameters involved in the thermal conversion processes. Moreover, pre-pyrolysis activity tackles biomass selection/analytical measurements, whereas the main pyrolysis activity tackles treatment methods, reactor types, operating processes, and the eventual product output. Other areas that need beginners' attention include high-pressure process reactor design strategies and material types that have a greater potential for biomass.

New insights into the influence of encapsulation materials on the feasibility of ultrasonic-assisted encapsulation of Mosla chinensis essential oil

The study aimed to estimate the feasibility of α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), and γ-cyclodextrin (γ-CD) to encapsulate Mosla chinensis essential oil (EO) by ultrasonic-assisted method. The physical properties variations, stabilization mechanisms, and formation processes of the inclusion complexes (ICs) were investigated using experimental methods, molecular docking, and molecular dynamics (MD) simulation. Scanning electron microscopy, fourier transform infrared spectroscopy, thermogravimetric analysis, and gas chromatography-mass spectrometry showed that the ICs were successfully prepared, which differentially improved the thermal stability and retained the chemical composition of EO. The dissolution profile showed that the Peppas model can be used to describe the diffuse release mechanism of EO. Finally, molecular docking and MD simulation theoretically confirmed the interaction and conformational changes of carvacrol (the main active component of Mosla chinensis EO) inside the cavity of CDs. The results indicate that hydrogen bonding was the primary driving force for the carvacrol spontaneous access to the cavity. Further, a binding dynamic balance occurs between carvacrol and β-CD, whereas a bind and away dynamic balance occurs in the IC between carvacrol and α-CD, γ-CD. The comprehensive results show that the medium cavity size of β-CD is a suitable host molecule for Mosla chinensis EO of encapsulation, release, and stabilization. A combination of experimental and theoretical calculations is useful for the pinpoint targeted design and optimization of CD molecular encapsulation of small entity molecules. β-CD was rationally screened as a better candidate for stabilizing EO, which provides an option for a meaningful path to realistic EO applications.

Conversion of solid wastes and natural biomass for deciphering the valorization of biochar in pollution abatement: A review on the thermo-chemical processes

This overview addresses the formation of solid trash and the various forms of waste from a variety of industries, which environmentalists have embraced. The paper investigates the negative effects on the environment caused by unsustainable management of municipal solid trash as well as the opportunities presented by the formal system. This examination looks at the origins of solid waste as well as the typical treatment methods. Pyrolysis methods, feedstock pyrolysis, and lignocellulosic biomass pyrolysis were highlighted. Explain in detail the various thermochemical processes that take place during the pyrolysis of biomass. Due to its carbon content, low cost, accessibility, ubiquitousness, renewable nature, and environmental friendliness, biomass waste is a unique biochar precursor. This study looks at the different types of biomass waste that are available for treating wastewater. This study discussed a wide variety of reactors. Adsorption is the standard method that is used the most frequently to remove hazardous organic, dye, and inorganic pollutants from wastewater. These pollutants cause damage to the environment and water supplies, thus it is important to remove them. Adsorption is both simple and inexpensive to utilize. Temperature-dependent conversions explain the kinetic theories of biomaterial biochemical degradation. This article presents a review that explains how pyrolytic breakdown char materials can be used to reduce pollution and improve environmental management.

Kinetic mechanism of wheat straw pellets combustion process with a thermogravimetric analyser

In this study, the combustion characteristics of two wheat straw pellets (WSP) (T1: 100% wheat straw and T5: 70% wheat straw; 10% sawdust, 10% biochar; 10% bentonite clay) were performed at a heating rate 20 °C/min under a temperature from 25 to 1200 °C in air atmosphere. A thermogravimetric analyser (TGA) was used to investigate the activation energy (Eα), pre-exponential factor (A), and thermodynamic parameters. The DTG/TG profile of WSP was evaluated by model-free and model-based methods and found the model-based method was suitable for WSP thermal characterisation. The result demonstrates that the thermal decomposition occurred in four stages, comprising four consecutive reaction steps. A→B→C→D→E→F. Further, the model-based techniques were best fitted with kinetic reaction models like Cn (nth-order reaction with auto-catalyst), Fn (reaction of nth order), F2 (second-order phase interfacial reaction) and D3 (diffusion control). The average Eα for Fn, Cn, D3 and F2 models were 164.723, 189.782, 273.88, and 45.0 kJ/mol, respectively, for the T1 pellets. Alternatively, for T5 pellets, the A was 1.17E+2, 1.76E+16, 5.5E+23, and 1.1E+3 (1/s) for F2, D3, Cn and Fn models. Overall, the thermodynamic properties showed that WSP thermokinetic reactions were complex and multi-point equilibrium, indicating a potentiality as a bioenergy feedstock.

Banana biomass waste: A prospective nanocellulose source and its potential application in food industry - A review

Bananas are among the most produced and consumed fruit all over the world. However, a vast amount of banana biomass is generated because banana trees bear fruit only once in their lifetime. This massive amount of biomass waste is either disposed of in agricultural fields, combusted, or dumped at plantations, thus posing environmental concerns. Nanocellulose (NC) extraction from this source can be one approach to improve the value of banana biomass. Owing to its superb properties, such as high surface area and aspect ratio, good tensile strength, and high thermal stability, this has facilitated nanocellulose application in the food industry either as a functional ingredient, an additive or in food packaging. In this review, two different applications of banana biomass NC were identified: (i) food packaging and (ii) food stabilizers. Relevant publications were reviewed, focusing on the nanocellulose extraction from several banana biomass applications as food additives, as well as on the safety and regulatory aspects. Ultimately, further research is required to prompt a perspicuous conclusion about banana biomass NC safety, its potential hazards in food applications, as well as its validated standards for future commercialization.

Valorization of millet agro-residues for bioenergy production through pyrolysis: Recent inroads, technological bottlenecks, possible remedies, and future directions

Millets are receiving increasing attention, lately, in view of their preeminent agronomic traits, nutritional significance, and renewed emphasis on highlighting their health benefits through national and international programs. As a consequence, a variety of millets are being cultivated in different parts of the world resulting in significant amount of millet agro-residues. Present study comprehends critical analysis of reported investigations on pyrolysis of different millet agro-residues encompassing (i) physico-chemical characterization (ii) kinetics and thermodynamic parameters (iii) reactors employed and (iv) relationship between the reaction conditions and characteristics of millets-derived biochar and its prospective applications. Based on the analysis of reported investigations, specific research gaps have been figured out. Finally, future directions for leveraging the energy potential of millet agro-residues are also discussed. The analysis elucidated is expected to be useful for the researchers for making further inroads pertaining to sustainable utilization of millet agro-residues in tandem with other commonly employed agro-residues.

Investigation of thermodynamic and kinetic parameters of Albizia lebbeck seed pods using thermogravimetric analysis

Thermodynamic and kinetic studies are very necessary to evaluate the conversion efficiency of biomass to energy. Therefore, this current work reported the thermodynamic and kinetic parameters of Albizia lebbeck seed pods through thermogravimetric analysis, which was carried out at temperatures from 25 °C to 700 °C, and heating rates of 5, 10, 15, and 20 °C/min. Apparent activation energies were determined by applying three iso-conversional model-free methods including Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), and Starink. Resultantly, average apparent activation energy values for the three models of KAS, OFW, and Starink were found to be 155.29, 156.14, and 155.53 kJ/mol, respectively. In addition, thermodynamic triplets such as enthalpy, Gibbs free energy, and entropy were obtained as 151.16 kJ/mol, 150.64 kJ/mol, and -7.57 J/mol·K, respectively. The above results suggest Albizia lebbeck seed pods could become a potential source for bioenergy production aiming to achieve the sustainable goal and waste-to-energy strategy.

A review on co-pyrolysis of agriculture biomass and disposable medical face mask waste for green fuel production: recent advances and thermo-kinetic models

The Association of Southeast Asian Nations is blessed with agricultural resources, and with the growing population, it will continue to prosper, which follows the abundance of agricultural biomass. Lignocellulosic biomass attracted researchers' interest in extracting bio-oil from these wastes. However, the resulting bio-oil has low heating values and undesirable physical properties. Hence, co-pyrolysis with plastic or polymer wastes is adopted to improve the yield and quality of the bio-oil. Furthermore, with the spread of the novel coronavirus, the surge of single-use plastic waste such as disposable medical face mask, can potentially set back the previous plastic waste reduction measures. Therefore, studies of existing technologies and techniques are referred in exploring the potential of disposable medical face mask waste as a candidate for co-pyrolysis with biomass. Process parameters, utilisation of catalysts and technologies are key factors in improving and optimising the process to achieve commercial standard of liquid fuel. Catalytic co-pyrolysis involves a series of complex mechanisms, which cannot be explained using simple iso-conversional models. Hence, advanced conversional models are introduced, followed by the evolutionary models and predictive models, which can solve the non-linear catalytic co-pyrolysis reaction kinetics. The outlook and challenges for the topic are discussed in detail.

Thermodegradation of naturally decomposed forest logging residues: Characteristics, kinetics, and thermodynamics

Combustion and pyrolysis characteristics, kinetics, and thermodynamics of naturally decomposed softwood and hardwood forest logging residues (FLR) were investigated using thermogravimetric analysis. Results showed that calorific values of fresh red pine, two-year decomposed, four-years decomposed, fresh red maple, two-year decomposed, and four-years decomposed were 19.78, 19.40, 20.19, 20.35, 19.27, and 19.62 MJ/kg, respectively. Hemicellulose pyrolysis peak only occurred in the hardwood thermodegradation process. Softwood had a higher pyrolysis yield of solid products (16.08-19.30%) than hardwood (11.19-14.67%). The average pyrolysis activation energy (E_a) of hardwood residue increased with the year after harvest, whereas softwood samples decreased. The average combustion E_a of hardwood samples increased first, then decreased, while that of softwood samples decreased continuously. Enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) were also investigated. This research will aid in understanding the thermal decomposition properties of naturally decomposed FLR from various years after harvest.

Determination of thermal degradation behavior and kinetics parameters of chemically modified sun hemp biomass

Sun hemp fibers are natural fibers obtained from plants grown in India and nearby countries. It is lignocellulosic biomass having the complex structure of hemicelluloses, cellulose and lignin. Chemical treatment of natural fibers is in practice to enhance the properties being used as reinforcement. Alkaline-treated fiber was sampled and thermal stability along with kinetic parameters was assessed with thermo gravimetric data at heating rates 10, 20 and 30 °C/min using four model-free methods Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Friedman (FM), Starink (STAR) along with Distributed activation energy model (DAEM) to calculate pre-exponential factor. The calculated activation energy E_a by these model-free methods were in the range of 93.3-104.8 kJ/mol and pre-exponential factor (A) was observed between the range 46.6 x10³-90.5 x10⁶/min by the DAEM method. The standard deviation (σ) calculated from average activation energy using all four methods was 4.5 kJ/mol, which showed the consistency in the methods employed to determine the activation energy of sun hemp.

Degradation of tetrabromobisphenol A (TBBA) with calcium hydroxide: a thermo-kinetic analysis

Thermal treatment of bromine-contaminated polymers (i.e., as in e-waste) with metal oxides is currently deployed as a mainstream strategy in recycling and resources recovery from these objects. The underlying aim is to capture the bromine content and to produce pure bromine-free hydrocarbons. Bromine originates from the added brominated flame retardants (BFRs) to the polymeric fractions in printed circuits boards, where tetrabromobisphenol A (TBBA) is the most utilized BFR. Among notable deployed metal oxides is calcium hydroxide, i.e., Ca(OH)₂ that often displays high debromination capacity. Comprehending thermo-kinetic parameters that account for the BFRs:Ca(OH)₂ interaction is instrumental to optimize the operation at an industrial scale. Herein, we report comprehensive kinetics and thermodynamics studies into the pyrolytic and oxidative decomposition of a TBBA:Ca(OH)₂ mixture at four different heating rates, 5, 10, 15, and 20 °C min^-1, carried out using a thermogravimetric analyser. Fourier Transform Infrared Spectroscopy (FTIR) and a carbon, hydrogen, nitrogen, and sulphur (CHNS) elemental analyser established the vibrations of the molecules and carbon content of the sample. From the thermogravimetric analyser (TGA) data, the kinetic and thermodynamic parameters were evaluated using iso-conversional methods (KAS, FWO, and Starink), which were further validated by the Coats-Redfern method. The computed activation energies for the pyrolytic decomposition of pure TBBA and its mixture with Ca(OH)₂ reside in the narrow ranges of 111.7-112.1 kJ mol^-1 and 62.8-63.4 kJ mol^-1, respectively (considering the various models). Obtained negative ΔS values suggest the formation of stable products. The synergic effects of the blend exhibited positive values in the low-temperature ranges (200-300 °C) due to the emission of HBr from TBBA and the solid-liquid bromination process occurring between TBBA and Ca(OH)₂. From a practical point of view, data provided herein are useful in efforts that aim to fine-tune operational conditions encountered in real recycling scenarios, i.e., in co-pyrolysis of e-waste with Ca(OH)₂ in rotary kilns.

Pyrolysis of tea and coffee wastes: effect of physicochemical properties on kinetic and thermodynamic characteristics

Physicochemical properties, kinetic pyrolysis and thermodynamic study of spent green tea, pure spent coffee grounds, spent coffee grounds blended with 50% torrefied barley and coffee husk were experimentally investigated using thermogravimetric analysis under an inert atmosphere to evaluate their thermochemical application. Five isoconversional methods were applied to determine effective activation energy (E _a) of the pyrolysis processes. All methods showed good agreement by determining fluctuating E _a values (150-500 kJ mol^-1). Complex E _a profiles with conversion were divided into four stages corresponding to thermal degradation of main biomass constituents (extractives, hemicellulose, cellulose and lignin), indicating that extractives decomposition was the least demanding reaction while lignin decomposition was the most demanding. The kinetic process was verified by reconstruction according to the Friedman parameters. The thermodynamic parameters were evaluated to determine the energy demand and efficiency throughout the process. The values obtained for physicochemical properties such as volatile matter (> 68%) and higher heating value (> 17 MJ kg^-1), average E _a (223-319 kJ mol^-1) and significant energy efficiency implied that these types of biomass waste have significant reactivity and consequently the highest potential for the production of bioenergy and a range of high-value chemicals and materials.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10973-022-11878-4.

Pyrolysis Kinetics of Byrsonima crassifolia Stone as Agro-Industrial Waste through Isoconversional Models

This study is aimed at the analysis of the pyrolysis kinetics of Nanche stone BSC (Byrsonima crassifolia) as an agro-industrial waste using non-isothermal thermogravimetric experiments by determination of triplet kinetics; apparent activation energy, pre-exponential factor, and reaction model, as well as thermodynamic parameters to gather the required fundamental information for the design, construction, and operation of a pilot-scale reactor for the pyrolysis this lignocellulosic residue. Results indicate a biomass of low moisture and ash content and a high volatile matter content (≥70%), making BCS a potential candidate for obtaining various bioenergy products. Average apparent activation energies obtained from different methods (KAS, FWO and SK) were consistent in value (~123.8 kJ/mol). The pre-exponential factor from the Kissinger method ranged from 10⁵ to 10¹⁴ min^-1 for the highest pyrolytic activity stage, indicating a high-temperature reactive system. The thermodynamic parameters revealed a small difference between E_A and ∆H (5.2 kJ/mol), which favors the pyrolysis reaction and indicates the feasibility of the energetic process. According to the analysis of the reaction models (master plot method), the pyrolytic degradation was dominated by a decreasing reaction order as a function of the degree of conversion. Moreover, BCS has a relatively high calorific value (14.9 MJ/kg) and a relatively low average apparent activation energy (122.7 kJ/mol) from the Starink method, which makes this biomass very suitable to be exploited for value-added energy production.

Influence of Intrinsic Physicochemical Properties of Agroforestry Waste on Its Pyrolysis Characteristics and Behavior

To obtain a comprehensive understanding of the qualitative and quantitative effects of the intrinsic properties of biomass on its pyrolysis characteristics and assess the behavior of agroforestry waste, thermogravimetric analyses of three representative agroforestry wastes, namely rape (Brassica campestris L.) straw (RS), apple (Malus domestica) tree branches (ATB), and pine (Pinus sp.) sawdust (PS), were carried out by pyrolysis under dynamic conditions (30 to 900 °C) at different heating rates of 5, 10, and 15 °C·min^-1. Correlation analysis showed that intrinsic physicochemical properties play distinct roles in different stages of pyrolysis. The ash content was negatively correlated with the temperature range (R₂) of the second stage (190-380 °C) of pyrolysis. The lignin content and the amount of pyrolysis residues (RSS) were positively correlated. Kinetic triplets, including the activation energy (Ea), pre-exponential factor (A), and reaction model [f(α)], were obtained using different methods, including the Flynn-Wall-Ozawa (FWO), Freidman, Kissinger-Akahira-Sunose (KAS), and Starink methods. The mean activation energy (Ea[mean]) for RS, ATB, and PS calculated by the different methods ranged from 167.15 to 195.58 kJ·mol^-1, 195.37 to 234.95 kJ·mol^-1, and 191.27-236.45 kJ·mol^-1, respectively. Correlation analysis of the intrinsic physicochemical characteristics and kinetic factors of agroforestry waste showed that the minimum Ea (Ea[min]) was significantly positively correlated with heat capacity (C₀) and negatively correlated with thermal diffusivity (D). The Ea[mean] and the maximum value of Ea (Ea[max]) significantly positively correlated with the sum content of cellulose and lignin, indicating that the contents of cellulose and lignin determines the energy required for the pyrolysis process of agroforestry waste. The mechanism of degradation involves the diffusion model (D1, D2, and D3), the growth model (A4), and the geometrical contraction model (R3). These results indicate that the pyrolysis of agroforestry waste is a complex process due to the heterogeneity of its intrinsic physicochemical properties.

Synthesis of carbon molecular sieves from agricultural residues: Status, challenges and prospects

Adsorption is the most promising technology used in the gas separation and purification process. The key success of this technology relies on the selection of an adsorbent. Activated carbon and zeolites are the most commonly used adsorbents in the separation of particular gas from gaseous mixtures. Activated carbon deriving from fossil and biomass-based resources has wide pore size distribution and thereby results in lower selectivity. Whereas, zeolites synthesized from natural minerals are expensive which increases the cost of the purification process. Taking this into concern, the quest for synthesizing low-cost and effective adsorbents has gained greater attention in recent years. Carbon Molecular Sieves (CMSs), are considered as an attractive alternative to replace the conventional adsorbents. Furthermore, CMSs exhibit higher selectivity and adsorption capacity, due to their narrow micropore size distribution (0.3-0.5 nm). CMSs are synthesized from any organic carbonaceous precursor with low inorganic content. Since most of the agricultural residues fall under this category, they can be used as a feedstock for CMSs production. The synthesis of CMSs involves three stages: carbonization, activation, and pore modification. In this review, physicochemical characteristics of various agricultural residues, the effects of carbonization process parameters, activation methods, and pore modification techniques adopted for producing CMSs are comprehensively discussed. The effect of deposition temperature, time, and flow rate of depositing agent on pore characteristics of CMSs is briefed. The prospects and challenges in CMSs production are also studied. The insights in this review provide guidelines for synthesizing CMSs from agro-residues.

Biomass valorization of Eichhornia crassipes root using thermogravimetric analysis

Present study focused on the thermo-chemical potential of waste biomass of Eichhornia crassipes or water hyacinth root (WHR). The pyrolysis-kinetic parameters are investigated using thermo-gravimetric analysis at the various heating rates (5, 10, 15, and 20 °C/min). Three model-free techniques, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starink, were used for the thermal kinetic analysis of biomass. The average activation energy for WHR biomass was determined using KAS, FWO, and Starink, with the values of 57.87, 64.69, and 58.27 kJ/mol, respectively. From the study it is observed that the roots of water hyacinth have rich in carbon, oxygen and hydrogen composition around 24%, 70% and 4% respectively. The higher heating value of water hyacinth root was observed around 15 MJ/kg.

Biochar and bio-oil fuel properties from nickel nanoparticles assisted pyrolysis of cassava peel

Direct biomass usage as a renewable fuel source and substitute for fossil fuels is discouraging due to high moisture, low energy density and low bulk density. Herein, thermogravimetric analysis (TGA) was conducted at various heating rates to determine peak decomposition temperatures for the dried cassava peels (DCP). The influence of pyrolysis temperature (300, 400, 500 and 600 °C) and heating rates (10, 20 and 30 °C/min) on the nickel nanoparticles catalyzed decomposition of DCP to produce biochar, bio-oil and biogas was investigated and characterized. The results revealed higher biochar (CBC) yield of 68.59 wt%, 62.55 wt% and 56.92 wt% at lower pyrolysis temperature of 300 °C for the different heating rates of 10, 20 and 30 °C/min. The higher carbon content of 52.39, 53.30 and 55.44 wt% was obtained at elevated temperature of 600 °C and heating rates of 10, 20 and 30 °C/min, respectively. At the pyrolysis temperature of 600 °C and heating rates of 10, 20 and 30 °C/min, the optimum yield of bio-oil (24.35, 17.69 and 18.16 wt%) and biogas (31.35, 42.03 and 46.12 wt%) were attained. A high heating value (HHV) of 28.70 MJ/kg was obtained for the biochar at 600 °C. Through the TGA, FTIR and HRSEM results, the thermal stability, hydrophobicity and structural changes of DCP and CBC samples were established. Similarly, the thermal stability of CBC samples increased with increasing pyrolysis temperature. Biochar with optimum fuel properties was produced at 600 °C due to the highest carbon content and high heating value (HHV). Improved kinematic viscosity (3.87 mm²/s) and density (0.850 g/cm³) were reported at the temperature of 300 °C and heating rate of 30 °C/min, while a higher pH (4.96), HHV (42.68 MJ/kg) and flash point (53.85 min) were presented by the bio-oil at the temperature of 600 °C and heating rate of 30 °C/min. Hence, DCP produced value-added biochar and bio-oil as renewable energy.

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Nickel nanoparticles successfully catalyzed the pyrolysis of CP biomass.

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Temperature and heating rates affected the yield of pyrolysis products.

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Fixed carbon content increased rapidly with temperature increase.

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The HHV of both biochar and bio-oil was higher than the DCP biomass.

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The fuel properties of biochar and bio-oil improved rapidly through NiNPs catalyzed pyrolysis.

Insights on kinetic triplets and thermodynamic analysis of Delonix regia biomass pyrolysis

The aim of this work was to study the pyrolysis of Delonix regia biomass with non-isothermal thermogravimetric experiments. The targeted objective was to investigate kinetic triplets and thermodynamic parameters. Five iso-conversional methods, namely Differential Friedman, Kissinger-Akahira-Sunose, Ozawa-Flynn-Wall, Starink, and Distributed Activation Energy, have been considered. In the adopted heating rates of 5-55 °C min^-1, the average activation energy and pre-exponential factor varied in the range 202.34-205.89 kJ mol^-1 and 4.98 × 10¹⁷ - 2.04 × 10²⁰ s^-1 respectively. Corresponding average enthalpy and Gibbs free energy varied from 196.84 to 200.87 kJ mol^-1 and from 182.64 to 206.41 kJ mol^-1 respectively. Pyrolysis mechanism have been confirmed by Avrami-Erofeyev (A4), power-law (P2 and P4) and reaction (F1, F2, and ≥ F5) according to Criado's master plots.

RETRACTED: Chemistry-Informed Neural Networks modelling of lignocellulosic biomass pyrolysis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the authors and the Editor-in-Chief. The article has reused text from the papers published by other authors in Combustion and Flame 240 (2022) 111992 https://doi.org/10.1016/j.combustflame.2022.111992 and the Journal of Physical Chemistry A 125 (2021) 1082–1092 https://doi.org/10.1021/acs.jpca.0c09316 without proper citation and discussion of the two articles. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. As such this article represents a misuse of the scientific publishing system. The scientific community takes a strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Insights into kinetic and thermodynamic analyses of co-pyrolysis of wheat straw and plastic waste via thermogravimetric analysis

This work studied the co-pyrolysis of wheat straw (WS) and polyethylene (PE) via thermogravimetric experiments from room temperature to 1000 °C at various heating rates (10, 20, and 30 °C/min). Thermal behavior revealed that the maximum decomposition of WS, PE, and their blend occurred in three temperature ranges, viz. 250 - 496, 200 - 486, and 200 - 501 °C. Kinetic parameters were determined using model-free isoconversional methods. Activation energy from KAS (163.56, 220.26 and 196.78 kJ/mol for WS, PE, and blend), FWO (165.97, 222.05, 198.86 kJ/mol for WS, PE, and blend), and Starink (163.45, 220.05, 196.46 kJ/mol for WS, PE, and blend) method was estimated. From among various solid-state kinetic models, first-order reaction kinetics and one and two-dimensional diffusion models dominated co-pyrolysis of WS and PE. Thermodynamic parameters confirmed the feasibility of co-pyrolysis of WS and PE while differential thermal analysis signified that endothermic and exothermic reactions occur simultaneously.

Biochar Synthesis from Mineral- and Ash-Rich Waste Biomass, Part 1: Investigation of Thermal Decomposition Mechanism during Slow Pyrolysis

Synthesizing biochar from mineral- and ash-rich waste biomass (MWB), a by-product of human activities in urban areas, can result in renewable and versatile multi-functional materials, which can also cater to the need of solid waste management. Hybridizing biochar with minerals, silicates, and metals is widely investigated to improve parent functionalities. MWB intrinsically possesses such foreign materials. The pyrolysis of such MWB is kinetically complex and requires detailed investigation. Using TGA-FTIR, this study investigates and compares the kinetics and decomposition mechanism during pyrolysis of three types of MWB: (i) mineral-rich banana peduncle (BP), (ii) ash-rich sewage sludge (SS), and (iii) mineral and ash-rich anaerobic digestate (AD). The results show that the pyrolysis of BP, SS, and AD is exothermic, catalyzed by its mineral content, with heat of pyrolysis 5480, 4066, and 1286 kJ/kg, respectively. The pyrolysis favors char formation kinetics mainly releasing CO₂ and H₂O. The secondary tar reactions initiate from ≈318 °C (BP), 481 °C (SS), and 376 °C (AD). Moreover, negative apparent activation energies are intrinsic to their kinetics after 313 °C (BP), 448 °C (SS), and 339 °C (AD). The results can support in tailoring and controlling sustainable biochar synthesis from slow pyrolysis of MWB.

Pyrolysis kinetics and pyrolysate composition analysis of Mesua ferrea L: A non-edible oilseed towards the production of sustainable renewable fuel

The present study on one non-edible oilseed (Mesua ferrea L) employs the pyrolysis process to understand the pyrolysate composition and the thermal degradation behavior of biomass. The physicochemical characterization of whole seed was investigated using thermogravimetric analysis at different heating rates (5, 10, 20, and 40 °C min^-1), bomb calorimeter, proximate/ultimate analysis. FTIR analysis confirmed the presence of the lignocellulosic compounds. Kinetic analysis of biomass was investigated using iso-conversional models such as Friedman, Kissinger-Akhaira-Sunose, Ozawa-Flynn-Wall, Starink, Distributed Activation Energy model, and Avrami model. Further, composition analysis of the pyrolytic vapor was analyzed using analytical fast pyrolysis coupled with gas chromatogram/mass spectrometer (Py-GC/MS) at 400, 500, 600 °C. This study confirmed that alkenes were major pyrolysates, followed by alkanes and esters. The current investigation suggested that Mesua ferrea L whole seed can be converted to valuable chemicals using pyrolysis.

Pyrolysis of pigeon pea (Cajanus cajan) stalk: Kinetics and thermodynamic analysis of degradation stages via isoconversional and master plot methods

Detailed analysis of thermo-kinetics, reaction mechanism, and estimation of thermodynamic parameters are imperative for the design of reactor systems in thermochemical conversion processes. Present investigation was aimed at exploring the pyrolysis potential of pigeon pea stalk (PPS) by thermogravimetric experiments at 10, 20, and 30 °C/min heating rates. Maximum devolatilization of PPS was found to take place below 480 °C. The average activation energy for PPS pyrolysis was found to be 95.97, 100.74, 96.24, and 96.64 kJ/mol by Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Starink, and Friedman method, respectively. Statistical analysis by one way analysis of variance method by employing Tukey test revealed that the difference in activation energy estimated from different methods was insignificant. Thermodynamic parameters (ΔH, ΔS_, and ΔG) together with reaction mechanisms were also evaluated. Difference in the activation energy and enthalpy was found to be less than 5 kJ/mol. R2 and R3 models were found best fitted with experimental PPS pyrolysis data.

Comparative study on fuel characteristics and pyrolysis kinetics of corn residue-based hydrochar produced via microwave hydrothermal carbonization

Corn residues are an important source of bioenergy. Due to their highly diverse lignocellulosic structures, the hydrochar produced from microwave-assisted carbonization of different corn residues may have distinct fuel properties and pyrolysis kinetics. This study comprehensively investigated the effect of processing temperature on the basic fuel properties of hydrochar and examined the pyrolysis behavior of hydrochar as a precursor through kinetic analysis. The results indicate that the fuel quality of corn straw hydrochar prepared by microwave-assisted hydrothermal carbonization at 230 °C was significantly improved over that of its feedstock, with a higher heating value of approximately 20.7 MJ/kg. Hydrochar prepared by microwave-assisted hydrothermal carbonization of corn cob at 230 °C presents noticeable environmental advantages because it contains the lowest ash and nitrogen contents (0.5% and 0.5%, respectively) and lower sulfur content (0.05%). Moreover, regarding the kinetic modeling, the Doyle and Coats-Redfern models, which are both first-order and single-step kinetic models, were identified as satisfactory in interpreting the key pyrolysis kinetic parameters. Additionally, the microwave-assisted hydrothermal process increased the apparent activation energy of hydrochar due to the increase in crystallinity and the increase in the number of CC and CO bonds.

Comprehensive approach of methods for microstructural analysis and analytical tools in lignocellulosic biomass assessment - A review

The trend in the modern world is to replace fossil fuels with green energy sources in order to reduce their environmental impact. The biorefinery industry, within this premise, needs to establish quantitative and qualitative analytical methods to better understand lignocellulosic biomass composition and structure. This paper presents chemical techniques (chromatography, thermal analysis, HRMS, FTIR, NIR, and NMR) and physicochemical techniques (XRD, optical and electron microscopy techniques - Confocal fluorescence, Raman, SPM, AFM, SEM, and TEM) for the microstructural characterization of lignocellulosic biomass and its derivatives. Each of these tools provides different and complementary information regarding molecular and microstructural composition of lignocellulosic biomass. Understanding these properties is essential for the design and operation of associated biomass conversion processing facilities. PAT, monitored in real-time, ensures an economical and balanced mass-energy process. This review aimed to help researchers select the most suitable analytical technique with which to investigate biomass feedstocks with recalcitrant natures.

Thermo-chemical potential of solid waste seed biomass obtained from plant Phoenix dactylifera and Aegle marmelos L. Fruit core cell

The present study explores thermo-chemical potential of two biomasses namely; Phoenix dactylifera seed (PDS) and Aegle marmelos L core (AMP). These biomasses contain high amount of cellulose and exhibit heating value of 3-18 MJ/kg. The thermal kinetic of both the biomasses have been extensively studied using thermogravimetric analysis (TGA) at four different heating rates 5, 10, 15, and 20 °C/min. Kinetic analysis was carried out using three model-free techniques including Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Starink. The average activation energy has been found to be 173.75, 172.94 and 170.71 kJ/mol, for PDS whereas 170.26, 167.24 and 164.80 kJ/mol, for AMP analyzed through KAS, FWO and Starink methods, respectively. Further, among all these models, the Starink model exhibits better result for the biofuels potential point of view.

Co-pyrolysis of petroleum coke and banana leaves biomass: Kinetics, reaction mechanism, and thermodynamic analysis

Insights into thermal degradation behaviour, kinetics, reaction mechanism, possible synergism, and thermodynamic analysis of co-pyrolysis of carbonaceous materials are crucial for efficient design of co-pyrolysis reactor systems. Present study deals with comprehensive kinetics and thermodynamic investigation of co-pyrolysis of petroleum coke (PC) and banana leaves biomass (BLB) for realizing the co-pyrolysis potential. Thermogravimetric non-isothermal studies have been performed at 10, 20, and 30 ^°C/min heating rates. Synergistic effect between PC and BLB was determined by Devolatilization index (D_i) and mass loss method. Kinetic parameters were estimated using seven model-free methods. Standard activation energy for PC + BLB blend from FWO, KAS, Starink, and Vyazovkin methods was ≈165 kJ/mol and that from Friedman and Vyazovkin advanced isoconversional methods was ≈171 kJ/mol. The frequency factor calculated for the blend from Kissinger method was found to be in the range of 10⁶-10¹⁶s^-1. Devolatilization index (D_i) showed synergistic effect of blending. The data pertaining to co-pyrolysis was found to fit well with R2 (second order) and D3 (three dimensional) from Z(α) master plot. Thermodynamic parameters, viz. ΔH ≈ 163 kJ/mol and ΔG ≈ 151 kJ/mol were calculated to determine the feasibility and reactivity of the co-pyrolysis process. The results are expected to be useful in the design of petcoke and banana leaves biomass co-pyrolysis systems.

Lignocellulosic composition based thermal kinetic study of Mangiferaindica Lam, Artocarpus Heterophyllus Lam and Syzygium Jambolana seeds

In the present study, pyrolysis of mangifera indica L., Artocarpus heterophyllus L. and jambolana seeds have been performed using thermogravimetric analysis. These biomasses have enriched lignocellulosic composition of hemicellulose (5-10%) and lignin (1-3%) which are unexplored. The TGA analysis was performed at various heating rates of 10, 15, 20, 25 and 30 °C/min from 25 to 600 °C. Kinetic investigation of the pyrolysis method using TGA statistics has been done using iso-conversional models of Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, Vyazovkin and Vyazovkin AIC. The apparent activation energies value ranged from 179.86 to 226.31 kJ/mol in the fractional conversion range of 0.1 to 0.7.

Pyrolysis of mustard straw: Evaluation of optimum process parameters, kinetic and thermodynamic study

The aim of this work was to evaluate the pyrolysis of mustard straw (MS) in a thermogravimetric analyser and in a tubular reactor to recognize its bioenergy capability. The model free methods of Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) and Vyazovkin were employed for kinetic analysis and Coats-Redfern (CR) method for elucidating the reaction mechanism. Response surface methodology (RSM) with central composite design technique was employed to optimize the pyrolysis process parameters to gain maximum amount of bio-oil. The highest bio-oil yield (44.69%) was obtained at the heating rate of 25 °C/min and at 500 °C under inert condition (N₂ gas flow rate = 100 ml/min). Further, FTIR and GCMS analysis of bio-oil revealed the presence of different functional groups and valuable chemicals, whereas physicochemical characterization revealed its fuel characteristic. The results confirmed the suitability of mustard straw as a feed-stock for obtaining a cleaner fuel and value added products.

Pyrolysis of mustard oil residue: A kinetic and thermodynamic study

Critical analysis of thermogravimetric data, characterization of the biomass, and kinetic and thermodynamic analyses are crucial in the design of efficient biomass pyrolysis systems. In this study, characterization, kinetic and thermodynamic analysis was performed for pyrolysis of mustard oil residue (MOR). Thermogravimetric analysis (TGA) with differential thermal analysis (DTA) was applied to study thermal decomposition behaviour of MOR at 10, 20, and 30 °C/min. FTIR and XRD analyses were used to characterize MOR. Average activation energy estimated from employed isoconversional methods was ≈155 kJ/mol. Variation in activation energy was found to be statistically insignificant as suggested by p-value of 0.992 by one-way ANOVA method. The pyrolytic temperature for MOR ranged from 234 to 417 °C. Reaction mechanism predicted as R3 (third order) and D3 (three dimensional). Thermodynamic parameters (ΔH_α, ΔG_α, and ΔS_α) showed that endothermicity increased from 0.2 to 0.8 conversion and product had highest energy at 0.8 conversion.

Determination of kinetic triplet, thermal degradation behaviour and thermodynamic properties for pyrolysis of a lignocellulosic biomass

Kinetic triplet, thermal degradation behaviour and thermodynamic properties of peanut shells were determined on the basis of non-isothermal thermogravimetric experiments conducted at three different heating rates under N₂ atmosphere. A single differential peak was observed for the devolatilization stage. The kinetic triplet of devolatilization stage was determined using Coats-Redfern and a combined method consisting the utilization of isoconversional and Criado methods. Kinetic validation revealed that the kinetic triplet determined using the combined method described the experimental values more precisely. The reaction mechanism ascertained by the combined method was D5-D3 combination. The E_a value was strong function of conversion, and computed using isoconversional methods (Boswell, Flynn-Wall-Ozawa, Starink, Tang) between 169 and 268 kJ/mol. Entalphy, entrophy and Gibbs energy changes were computed in 164-259 kJ/mol, -37-141 J/(mol.K) and 173-187 kJ/mol ranges, respectively. The comprehensive pyrolysis index values were also calculated, and shown to increase with increasing heating rate.

Studies on individual pyrolysis and co-pyrolysis of corn cob and polyethylene: Thermal degradation behavior, possible synergism, kinetics, and thermodynamic analysis

The knowledge on thermo-kinetics, synergistic effect, and reaction mechanism of pyrolysis/co-pyrolysis of biomass with plastics is crucial for designing efficient reactor system and subsequently the pyrolysis/co-pyrolysis process. The present work explores thermal response, kinetics, reaction mechanism and thermodynamic analysis of pyrolysis and co-pyrolysis of individual corn cob (CC) and polyethylene (PE), and their blend in the ratio of 3:1 (w/w). Thermogravimetric analysis (TGA) data was obtained under inert atmosphere at various heating rates of 10, 20, and 30 °C/min and synergistic effect in the co-pyrolysis of CC and PE is discussed. The obtained TGA data was processed using various model-free isoconversional methods like KAS, FWO, Friedman, Starink, and Vyazovkin for determination of kinetics of pyrolysis/co-pyrolysis process of CC and PE. Average activation energy for CC pyrolysis was estimated to be 240 ± 51.25 kJ/mol, 240 ± 51.51 kJ/mol, 237 ± 49.67 kJ/mol, and 245 ± 52.10 kJ/mol according to KAS, Starink, FWO, and Vyazovkin models, respectively. Statistical analysis showed that the variation in reported values of activation energy was not significantly different (p = 0.994). Similar statistically insignificant difference was also observed for pyrolysis of PE and co-pyrolysis of CC and PE. Results showed that co-pyrolysis (CC + PE) requires 10% less activation energy than pyrolysis of CC alone. For the co-pyrolysis process, the extent of synergistic effect was discussed by difference in mass loss (ΔW). Investigation also revealed that residue left for co-pyrolysis of CC and PE is 50% less than pyrolysis of CC alone showing synergistic effect during co-pyrolysis. Thermodynamic parameters were calculated to illustrate complex mechanism of the process. Third order reaction, 3D diffusion Jander, and Ginstling-Brounshtein (D4) models were found to be best fitted for CC pyrolysis, PE pyrolysis, and co-pyrolysis, respectively. Results obtained are expected to be useful in the design of corn cob and waste polyethylene co-pyrolysis systems.

Pyrolysis of corn cob: physico-chemical characterization, thermal decomposition behavior and kinetic analysis

Bioenergy out of lignocellulosic biomass, especially from agricultural crop residues, is making massive inroads in our quest for sustainable environment. In the present study, detailed physico-chemical characterization, thermal degradation characteristics, and kinetics of pyrolysis of corn cob are reported. Thermogravimetric experiments were performed at different heating rates, such as, 10, 20, and 30 °C/min in an inert atmosphere. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves inferred the thermal behavior characteristics of corn cob. Significant content of cellulose and hemicellulose put together (76.23%) suggested tremendous potential of corn cob to give enhanced yield of bio-oil through pyrolysis. Maximum mass loss of 61.92% for corn cob was observed in the temperature range of 180–360 °C. The kinetic parameters for pyrolysis of corn cob were determined by employing model-free isoconversional methods like, Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, and Starink. Activation energy from FWO (62.44 kJ/mol) and Starink (61.74 kJ/mol) method for pyrolysis of corn cob was found to be in close proximity. The results revealed prospective bioenergy potential of corn cob as a feedstock for pyrolysis process.