Coats-Redfern Method Research Articles

Mesoporous, high surface area and microrod-shaped cobalt (II) coordination polymer for assessment of molecular structure, thermolysis and non-isothermal kinetics parameters

This study is significant as it presents the assessment of molecular identification, thermal degradation, and non-isothermal kinetics of a cobalt (II) coordination polymer [Co (II) CPs] synthesized from suberoyl bis (2-ethoxybenzamide) (sbebz) and cobalt acetate through the condensation process. The condensation product sbebz was obtained from suberoyl chloride and 2-ethoxybenzamide. The XRD, FT-IR, Raman, and XPS investigated as aspects to identify its structure, purity, and chemical state. The morphological facet was confirmed by SEM and TEM. The morphology data revealed a microrod-shaped morphology of Co (II) CPs with an average particle size 0.7 µm to 1 µm. The pore size, and surface properties were examined by Brunauer-Emmett-Teller (BET) and atomic force microscopy (AFM), revealing a highly large surface area (1076 m2/g), mesoporous and monodisperse nature. The molecular interaction of ligand was estimated using protein molecule. The thermal-decomposition behavior and non-isothermal kinetics of Co (II) CPs were estimated at different heating rates (5 °C/min, 10 °C/min, 15 °C/min, and 20 °C/min) under nitrogen atmosphere by thermogravimetry/Derivative thermogravimetry (TG/DTG). As-synthesized Co (II) CPs show enhanced thermal stability compared to the ligand (sbebz). The multiple heating TG/DTG curve exhibits a more or less identical degradation profile/pattern. The kinetic parameters like order of reaction (n), pre-exponential Arrhenius factor (A), activation entropy (∆s), activation energy (Ea), activation free-energy (∆G), and activation enthalpy (∆H) were calculated using Coats-Redfern (CR) method.

Kinetic and thermodynamic analysis of the PET-date seed mixture co-pyrolysis using Coats-Redfern method

This study focuses on improving the polyethylene terephthalate (PET) pyrolysis outcome by incorporating date pits in a balanced 50–50 mixture. The effect of date pit addition on the co-pyrolytic process is determined via thermal analysis using the Coats-Redfern method, which provides an estimation of the activation energy and the pre-exponential factor of the PET-Date mixture. The results demonstrate that the majority of the reaction mechanisms exhibit enhanced performance for the modified mixture, requiring 70 % less reaction energy on average. Hence, a positive effect is observed on the PET pyrolysis, thus highlighting its potential for biomass incorporation. This study provides valuable insights into optimising the co-pyrolytic processes for sustainable waste management and resource utilization practices.

An Investigation on the Thermal Degradation Kinetics of Wood-Polymer Composites Used in Interior Automobile Panels via Non-Isothermal Thermogravimetry

Wood plastic composites (WPCs) offer a promising alternative for various automotive components, combining the benefits of wood and polymers such as lightness, strength, and sustainability. However, determining decomposition kinetics is challenging due to the intricate composition of WPCs. Therefore, this research work focused to analyze the relationship between the thermal degradation of WPCs, the degradation atmosphere, and the kinetics. The kinetic parameters were evaluated by Coats and Redfern method based on a set of TGA experiments under variable atmospheres (inert and oxidative) using 10 ℃/min heating rate. Thermograms demonstrated significant differences in the thermal properties of WPC when subjected to oxidative and inert atmospheres, despite two conditions having the same number of thermal degradation zones. It has been suggested that the process of thermal decomposition of WPC contains three weight loss segments under inert and oxidative atmosphere according to the Gaussian multi-peak fitting function. The Coats-Redfern method showed multi-step chemical kinetics and more accurately characterizes the decomposition behavior of WPC, attributing to its multi-compositional properties. Proposed reaction schemes had regression coefficients higher than 0.9809 to obtain reaction order, activation energy and pre-exponential factor.

Kinetics and mechanism of thermal and thermo-oxidative degradation for high-density polyethylene modified by fullerene and its derivative

To investigate the effect of fullerene (C60) and its iron compound (C60-Fe) on the thermal and thermo-oxidative degradation mechanism of high-density polyethylene (HDPE), the Kissinger method, Flynn-Wall-Ozawa method and Coats-Redfern methods are used. The data of thermal and thermo-oxidative degradation are achieved through the thermogravimetric (TG) analysis, and the trapping free-radical ability and the dispersion of C60 or C60-Fe in matrix are characterized by the electron spin resonance (ESR) and transmission electron microscopy (TEM). C60 and C60-Fe improve effectively the thermal and thermo-oxidative stability of HDPE. In N2, C60 and C60-Fe do not change the degradation mechanism of HDPE, and the degradation rate is determined by the random generation and growth of free-radicals. In air, C60 changes the reaction order (n) of HDPE at the oxidation stage and the degradation mechanism at the random fracture. C60-Fe changes the thermo-oxidative mechanism of HDPE due to the formation of cross-linked network.

In-Depth Study on Synergic Interactions and Thermo-Kinetic Analysis of (Wheat Straw and Woody Sawdust) Biomass Co-Pyrolysis over Mussel Shell-Derived CaO Catalyst Using Coats–Redfern Method

The behavior of wheat straw biomass (WS), woody sawdust biomass (WB), and their blends during catalytic co-pyrolysis are analyzed in the presence of CaO catalyst, which is obtained from the calcination of mussel shells. Synergy analysis of blends and pure materials is measured by studying the difference between theoretical and experimental values of wt.%/min, (RL%), and (WL%), which correspond to maximum weight loss rate, residue left, and weight loss, respectively. The Coats–Redfern method is utilized for evaluating the thermo-kinetic properties. The chemical reaction order model F1 is the best model that describes the Ea of 60.05 kJ/mol and ∆H, ∆G, and ∆S values of 55.03 kJ/mol, 162.26 kJ/mol, and −0.18 kJ/mol.K, respectively, for the optimum blend 80WS−20WB, reducing the thermo-kinetic properties. Model D3 showed better results for the Ea, ∆H, ∆G, and ∆S for the 5% CaO blend, which certified the viability of co-pyrolysis of WS and WB, while DTG indicated that exothermic and endothermic reactions occur together.

Comprehensive thermal properties, kinetic, and thermodynamic analyses of biomass wastes pyrolysis via TGA and Coats-Redfern methodologies

This study comprehensively analyzes the thermal decomposition characteristics as well as the kinetic and thermodynamic parameters of five biomass wastes, including coffee husk, groundnut shell, macadamia nutshell, rice husk, and tea waste, using Thermogravimetric Analysis (TGA) and the Coats-Redfern method. The TGA experiments were conducted on a PerkinElmer STA 6000 instrument under an inert N2 atmosphere with a heating rate of 20 °C/min, spanning a temperature range from 25 °C to 950 °C. The results identified three distinct pyrolysis stages: drying, devolatilization, and char formation, with macadamia nutshell demonstrating the highest thermal reactivity and efficient devolatilization characteristics, reflected by its lowest initial devolatilization temperature (175 °C) and highest peak temperature (380 °C). Kinetic analysis revealed that coffee husk had the highest overall activation energy (Ea) of 60.59 kJ/mol, indicating complex thermal degradation behavior. The thermodynamic evaluation showed that coffee husk also exhibited the highest enthalpy change (ΔH=55.46 kJ/mol) but the lowest Gibbs free energy change (ΔG=148.34 kJ/mol), suggesting high energy requirements for decomposition but relatively more spontaneous reactions compared to other biomass types. Macadamia nutshell demonstrated high ΔG (163.24 kJ/mol) and moderate ΔH (32.44 kJ/mol), reflecting greater resistance to spontaneous decomposition. The comprehensive pyrolysis index (CPI) and devolatilization index (Ddev) confirmed macadamia nutshell as the most reactive biomass, while rice husk exhibited the lowest reactivity. The findings highlight the importance of multi-step kinetic analysis for accurately understanding pyrolysis processes, providing critical insights for optimizing biomass conversion for energy production. Future research should explore co-pyrolysis with varied biomass mixtures and advanced kinetic modeling to enhance energy yields.

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.

Holistic approach for sequential transesterification and pyrolysis of microalgal biomass: Kinetic and thermodynamic analysis of pyrolysis using model-free and model-based approaches

Due to the renewability and sustainability, biofuels derived from algae are considered as competitive substitutes for fossil fuels. Present study investigated a holistic approach for sequential transesterification and pyrolysis of microalgal biomass, i.e. Chlorella minutissima. This study explores the complete utilization of algal biomass through sequential chemical (transesterification) and thermochemical (pyrolysis) processes. First, the lipids were extracted and converted to eco-friendly biodiesel using catalytic route. Then lipid-extracted microalgae were pyrolyzed via thermogravimetric analyzer at four heating rates, namely 5, 10, 20 and 30 °C/min. The model-free isoconversional Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Vyazovkin models were used to analyze the kinetics and thermodynamics of algal pyrolysis. The activation energy obtained for the pyrolysis of Chlorella minutissima utilizing KAS, FWO and Vyazovkin were 146.78, 148.86, 147.11 kJ/mol, respectively. Positive ΔH values from KAS, FWO, and Vyazovkin show an endothermic nature of the process. The mean ΔH was found to be 142.81, 143.97, and 142.82 kJ/mol, while the ΔG was 151.9, 152.20, and 161.40 kJ/mol, respectively for KAS, FWO, and Vyazovkin approaches, at 10 °C/min heating rate. Importantly, this study also revealed that the phase interfacial model was the most appropriate model to represent the degradation process using Coats-Redfern method at 5 oC

Metal-based compounds: Synthesis and characterization of new thiazole-based iridium and palladium complexes with potential anticancer and other biological activities

Thiazoles and their derivatives are one of the most active classes of compounds known for their wide spectrum of bioactivity. Metal complexes, based on them, show antitumor potential that is attractive for investigations. Herein, we report 6 new biologically active thiazole-based complexes have been synthesized. The iridium- and palladium-based coordination compounds obtained by the precipitation method were characterized using elemental analysis (EA), Fourier-transform infrared spectroscopy (FTIR), magnetic measurements, thermogravimetric analysis coupled with mass spectrometry (TGA-MS), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Spectroscopic data helped to propose the formulas of the complexes and indicated that all ligands acted in a monodentate manner. Water molecules were identified by thermal analysis and FTIR spectroscopy. Mathematical analysis and evaluation of thermodynamic parameters including entropy (ΔS), Gibbs free energy (ΔG), and activation energy (E) were performed using the Coats–Redfern method for all complexes. The biological potential (anticancer, antibacterial, and antifungal properties) of compounds was analyzed by biological evaluation studies. Investigated CT-DNA studies revealed that the prepared compounds were intercalatively bound to the DNA. Cytotoxicity analyses showed that complexation with Ir(III) increased the toxicity of L2 towards both tested cell lines (LN-229 and MDA-MB-231), while complexation of L3 with Pd(II) significantly increased cytotoxic activity against LN-229. Due to this, the further biological studies, such as apoptosis/necrosis detection, cell cycle analysis and JC-1 fluorescence measurements were performed on this pair of compounds.

Effect of acidity of solid acid catalysts during non-oxidative thermal decomposition of LDPE

AbstractThermal decomposition of low-density polyethylene (LDPE) was monitored by thermogravimetry under N2 atmosphere in the presence of solid acid catalysts such as alumina (α-Al2O3, γ-Al2O3), crystalline silica-alumina (SA, molar ratio of Si/Al = 0.19) and amorphous silica-alumina catalysts (ASA, molar ratio of Si/Al = 4.9). Crystal structure and surface area of solid acid catalysts were measured by XRD and BET, respectively. The strength and distribution of acid sites of solid acid catalysts were estimated by NH3-TPD. It was observed that total acidity strength is in the order of ASA (1.77 μmmol NH3/g) > AS (1.42 μmol NH3/g) > γ-Al2O3 (1.06 μmol NH3/g) > α-Al2O3 (0.06 μmol NH3/g). Thermal degradation behavior of LDPE with and without solid acid catalyst was monitored by TGA, where heating rates (β) of 5, 10, and 20 °C/min were employed under an inert atmosphere, and their activation energies (Ea), onset temperatures (Tinitial), decomposition temperatures (Tdecomp) were calculated and compared. The activation energy (Ea) was evaluated using the Coats-Redfern method. Solid acid catalysts with stronger acidity and higher surface area showed a decrease in activation energy and onset temperature. Activation energy of LDPE over ASA catalyst is decreased to 97.3 kJ/mol from thermal decomposition of LDPE without catalyst of 117.2 kJ/mol under heating rate of 10 °C/min. The isothermal decomposition of LDPE was monitored at 300 °C for 3 h with a heating rate of 10 °C/min, where 13.1% and 24.2% wt. loss were observed over SA and ASA, respectively, while only 0.7% wt. loss was observed for LDPE without a solid acid catalyst. Graphical abstract Single step decomposition of LDPE Thermal degradation behavior of LDPE monitored by TGA, with different heating rates (β) of 5, 10, 20 °C/min.

Kinetic, thermodynamic and artificial neural network prediction studies on co-pyrolysis of the agricultural waste and algae

The thermal decomposition behaviors of Maize straw (MS), algae (AL), and their blends were studied in a thermogravimetric analyzer to evaluate the bio-energy potential in this research. The blends neutralized violent reactions of each other at the second pyrolysis stage, and S and CPI respectively achieved the lowest points at 40%MS-60%AL and 60%MS-40%AL. The average Eα calculated by OFW, KAS, Starink and Friedman methods changed from 6.94 to 68.03 kJ/mol, 14.61–85.76 kJ/mol, 14.31–85.12 kJ/mol, respectively. When α was in range of 0.2–0.6, the Coats-Redfern method was calculated within 19.39 kJ/mol. KAS and Starink methods seemed more reliable. Reaction mechanism analyzed by Criado method show that AL was significantly different from that of MS. In addition, thermal degradation input by biomass types, heating rate and temperature were well predicted by artificial neural network (ANN). ANN 19 modal (3-5-15-1) was obtained the best (MSE = 0.0978 and R2 = 0.9999). The modal was utilized to predict the thermogravimetric curve without experiment, DTGmax of 70%MS-30%AL was the highest. While overfitting occurred in the high-temperature ranges (>700 °C). This study proves the potential of ANN modeling for producing derived energy from co-pyrolysis of biomass and other residues.

Pyrolysis characterization and kinetic analysis of typical coals in western China: effects of coal type, particle size and heating rate

ABSTRACT The three typical coals selected in this study (Shuangyi coal (SY), Hengsheng coal (HS) and Ningxia anthracite (NX)) are widely used in western China, but their pyrolysis characteristics have been less studied. In this study, based on the simultaneous thermal analysis-Fourier transform infrared spectroscopy (STA-FTIR) technique, the effects of different coal types, particle sizes and heating rates on the pyrolysis characteristics of coal powder were investigated. The results showed that the weight loss behaviors of different types of coals with different particle sizes varied, as influenced by the type of coal and heat transfer. When the particle size increased from 170 μm to 380 μm, the weight loss rate decreased by 2.95% and 24.45% for SY and NX coals while increased by 4.81% for HS coals; whereas for the maximum decomposition rate, both SY and HS coals showed an increasing tendency (increased by 2.76% and 9.32%), while NX coals decreased by 21.43%. The R2 of the three coal DTG curves fitted by subcurves was all 0.999, which proved that the nature of coal weight loss was the coupling effect of certain types of chemical reactions or covalent bond breakage. Real-time infrared spectroscopy was combined with covalent bonding to explore the major gas products and their influence by particle size. The activation energies at different temperatures were calculated by the Coats-Redfern method, in which the activation energies of the fast pyrolysis stage of HS coal were 1.68 and 2.75 times higher than those of the other two stages, 1.79 and 3.03 times higher than those of SY coal, and 1.99 and 1.11 times higher than those of NX coal, respectively.

Study of synergistic behavior during bituminous coal-cow manure co-gasification: The role of intrinsic AAEM and organic matter

Co-thermal chemical conversion of coal and biomass is one of the important ways to realize efficient and clean utilization of coal. In this study, a typical Ningdong coal-Yangchangwan bituminous coal and cow manure were used to study the synergistic effect of intrinsic alkali, alkaline earth metals (AAEM) and organic matter on the co-gasification of coal and biomass by thermogravimetry analyzer (TG). The results showed that AAEM had obvious synergistic promotion effect on the gasification of a bituminous coal-cow manure mixture in the isothermal gasification (1000 ℃), whereas the organic matter will show the opposite effect on the process. To further investigate the effect of organic matter on the gasification process, the influence of organic matter on non-isothermal (25-1000 ℃) gasification reaction was investigated with heating rate of 10 ℃ /min, the kinetic parameters of the gasification reaction were obtained by Coats-Redfern method. The increase of biomass mass fraction in the sample facilitates the migration of alkali metals from the material to the solid phase. The possible mechanism of the synergistic effect of intrinsic AAEM/organic matter on the co-gasification process was proposed.

Pyrolysis kinetic analysis and model constructions of different ranks of coal and validation by GA–BP neural networks

In the current steel industry, environmental pressures are mounting. If the reducing gases generated from coal pyrolysis can be utilized for reducing iron ore, the goal of low-carbon production with controllable costs can be achieved. However, the release of volatile content in coal has a significant impact on the pyrolysis process and final products. Therefore, in this study, the pyrolysis characteristics and gaseous products of four types of coal with different volatile matter content was investigated by thermogravimetry-mass spectrometry (TG-MS) technology. The results showed that coals with higher volatile matter content demonstrated stronger reactivity during pyrolysis. As the volatile matter content in coal increased, the starting temperature for releasing the reducing gases decreased, leading to a significant increase in the released gas volume. In addition, the three kinetic factors were calculated by isoconversional method, distribution of the activation energy model (DAEM) and Coats-Redfern (CR) method respectively, and the pyrolysis reaction mechanism function suitable for all coal types was reconstructed based on common solid reaction models. Finally, a predictive model based on a GA-improved back-propagation neural network (BPNN) was developed, which useing 21 input parameters to predict the TG curves, activation energy (E), lnA and mechanism function (fα) and achieving R2 values above 0.95. This study contributes to a comprehensive understanding of the pyrolysis mechanism of coals with different volatile matter content, providing scientific guidance for effective utilization.

Pyrolysis characteristics of different types of tobacco and its correlation with the released aroma components under heating condition

An in-depth insight into the pyrolysis characteristics of tobacco is of great significance for the utilization of tobacco wastes. The effects of glycerol addition on the pyrolysis characteristics and distribution of aroma components of four types of tobacco was investigated in this study by using thermogravimetry and self-built rapid heating furnace capture and GC-MS analysis. Further, correlation network analysis was used to study the correlation between pyrolysis characteristics and released aroma components. It was found that the thermal weight loss behavior of different samples exhibited both commonalities and differences, the thermal weight loss process could be divided into four stages. After the application of glycerol, the overall performance of all types of tobacco leaves at stage II showed that DTGmax2 and WL2 increased, and glycerol had a relatively obvious effect on the pyrolysis characteristic parameters of flue-cured tobacco. Pyrolysis kinetic analysis based on Coats-Redfern method showed that the activation energy and pre-exponential factor of tobacco samples were decreased after the addition of glycerol. Under the heating condition, the total amount of released aroma components from each type of tobacco followed the order of burley tobacco > flue-cured tobacco >oriental tobacco > yellow sun-cured tobacco. The release amount of heterocyclic and olefins compounds from burley tobacco were higher, while flue-cured tobacco released higher contents of esters, ketones and furans compounds. The addition of glycerol promoted the release of aroma components. In terms of correlation, Tmax2 was negatively correlated with esters, aldehydes, and furans compounds, and positively correlated with DTGmax3. Tmax3 was significantly correlated with a lot of indicators, positively with acids, aldehydes, and furans compounds, but negatively with olefins and heterocyclic compounds.

Thermal decomposition of Syagrus romanzoffiana palm fibers: Thermodynamic and kinetic studies using the coats-redfern method

This work uses thermogravimetric analysis to perform the thermokinetics and thermodynamic studies of Syagrus romanzoffiana fibers (SRFs). In a nitrogen environment, SRFs were heated non-isothermally between 25 and 800 °C at four heating rates of 5 °C/min, 10 °C/min, 15 °C/min, and 20 °C/min. According to thermogravimetric examination, the pyrolysis of SRFs occurred in three steps. The second stage has had its kinetic and thermodynamic characteristics determined. The low-temperature stable components were decomposed at temperatures ranging from 218 to 376 °C, 218–391 °C, 218–394 °C, and 218–398 °C at heating rates of 5 °C/min, 10 °C/min, 15 °C/min, and 20 °C/min, respectively. The Coats-Redfern method was applied to twenty-one distinct kinetic models representing four key solid-phase reaction processes. The diffusion model using the Zhuravlev equation is the best-fitted model, having the most outstanding correlation coefficient values (R2 > 0.99) for all heating rates. Heating rates of 5, 10, 15, and 20 °C/min resulted in activation energy values of 114.02, 118.77, 119.44, and 113.89 kJ/mol, respectively. Thermodynamic characteristics (ΔH, ΔG, and ΔS) were computed using kinetic parameters. The data presented here helps evaluate SRFs as a possible biomass renewable energy source for building reactors and generating chemicals.

Slow pyrolysis of Agave americana L. fibers: Analysis of kinetics and thermodynamics using the coats-redfern method at different heating rates

This study employed thermogravimetric analysis (TGA) alongside the Coats-Redfern method (CRM) to investigate the thermal degradation's kinetics and thermodynamics of fibers extracted from the flower stalk of Agave americana (FSAA). We explored FSAA fibers' thermal behavior across varying heating rates (HRs) to elucidate complex reaction mechanisms and estimate critical parameters. TGA experiments at 5, 10, and 20 °C/min HRs reveal a multi-step breakdown process supported by solid coefficients of determination (R2 > 0.99). Activation energy values, ranging from 83.6 to 210.1 kJ/mol, vary with HR, providing insights into thermal decomposition kinetics. Thermodynamic parameters, including variations in entropy (ΔS), Gibb's free energy, and enthalpy, shed light on spontaneity and energy transfer during the process. Negative ΔS values suggested reduced disorder during thermal decomposition. This study represented a novel investigation into the thermal behavior of fibers extracted from the FSAA for the first time, using CRM in conjunction with TGA. Through comprehensive analysis, we elucidated the kinetics and thermodynamics of FSAA fiber degradation across various HRs. Our findings shed light on the intricate reaction mechanisms underlying FSAA fiber decomposition, providing valuable insights for potential applications in biofuel production and composite materials.

Recovery of iron from copper slag using jatropha oil as a green reductant: Investigation of pyrolysis analysis, reaction kinetic and artificial neural network model prediction

Jatropha oil (JO) is a non-edible vegetable oil and a potential renewable energy source. In this paper, JO was proposed as a reductant to recover iron from copper slag (CS), and the effects of JO dosage, reduction temperature and reduction time on the recovery of iron by deep reduction of CS were investigated. Based on Coats-Redfern method, a thermogravimetric analyzer was used to explore the reactivity, mass loss behavior, and kinetic mechanism of CS reduction by JO, and to compare the reduction characteristics of anthracite and JO char when used as a reductant. Additionally, artificial neural network (ANN) modeling was used to predict the effects of reductant type, temperature, and heating rate on mass loss during CS reduction. The results showed that the optimum condition for CS reduction when JO was used as the reductant was 3 wt% JO at 1250 °C for 45 min, which resulted in 84.97 % Fe recovery and 94.58 % Fe grade in CS; the reduction mechanism of CS followed a one-dimensional diffusion model (D1); and ANN5 (15*1) was the optimum ANN model to predict the reduction of CS. This research introduces innovative strategies for the environmentally friendly and efficient recovery of iron from iron-containing furnace slag.

Hydrothermal carbonization of sugar beet pulp: optimization and characterization

In this study, the optimum hydrothermal conditions of sugar beet pulp were investigated by Response Surface Methodology (RSM) based on Central Composite Design (CCD). The hydrochar obtained from sugar beet pulp (SBP) was optimized for maximum yield and carbon content. Process conditions were chosen with reaction temperatures of 200–240 °C, residence time 60–150 min, and biomass to water ratio of 1:3–1:10. The yield and carbon content of the hydrochar varied with the process parameters. In order to obtain hydrochar with the highest yield and carbon content in optimization, the reaction temperature should be 220.74 °C, the biomass to water ratio should be 1:3, and the residence time should be 95.58 min. High heating value, energy and mass yield, and energy densification ratio of sugar beet pulp and hydrochar were also investigated. The products were characterized using FT-IR, SEM, and ultimate analysis techniques. The Coats-Redfern method was used to estimate the kinetic parameters of the combustion processes. The activation energy values of SBP and SBP-HC products were calculated as 13.88 and 11.46 kJ/mol, respectively. The kinetic data were used to determine the thermodynamic parameters (ΔH, ΔG, and ΔS). As a result, the properties of hydrochar produced from sugar beet pulp under optimum conditions have been extensively investigated and the results have shown that hydrochar has potential for use in different areas.

Investigation on the thermochemical characteristics, kinetics and evolved gases for typical kitchen waste pyrolysis

Kitchen waste is a complex biomass waste, whose composition and properties vary with factors such as source, season and region. It is challenging to classify and characterize it. A thermogravimetric and kinetic study was performed to estimate pyrolysis characteristics and gas emissions of starch, peel, nut shell, and vegetables. Samples underwent pyrolysis in the Simultaneous Thermal Analysis from room temperature to 1200 K at different heating rates of 10, 20, 30 and 50 K/min. The starch had the narrowest pyrolysis temperature range, while nut shell exhibited the highest residual rate. The average activation energy for pyrolysis process calculated using Coats–Redfern method was in order of starch > vegetable ≈ nut shell > peel. The gaseous products and typical functional groups of the released volatiles were identified using specific information from Fourier Transform Infrared Spectroscopy (FTIR) and Mass Spectrometry (MS). These primarily included small inorganic molecules, aldehydes, aromatics, ethers, furans, ketones, organic acids, and phenols. Aliphatic hydrocarbons significantly contributed to the total gas yield and were the most abundant for all samples. The characteristic ion fragment with m/z = 60 was only observed in peel and nut shell, while m/z = 58 ion fragments were exclusive to starch and vegetables. The practical research can provide theoretical basis for the resource utilization and environmental management of kitchen waste.