Min Heating Rate Research Articles

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.

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

Highly efficient and eco-friendly process for selective recovery of copper from waste printed circuit boards via pyrolysis and ammoniacal solvoleaching

This study proposes a process combining pyrolysis and ammoniacal solvoleaching to selectively recover Cu from waste printed circuit boards (WPCBs). Optimal pyrolysis conditions were determined by investigating parameters such as temperature, heating rate, N2 flow rate, holding time and particle size. Under the conditions: 500 °C temperature, 20 °C/min heating rate, 0.3 L/min N2 flow rate, 10 min time and +9.50 mm particle size, ∼25% of weight loss was obtained. The pyrolyzed mass underwent further physical separation process involving impact crushing, magnetic- and gravity separations to enrich metals into a concentrate. Copper in the resulting concentrate was selectively extracted using a one-stage ammoniacal leaching and solvent extraction process (ammoniacal solvoleaching), employing an oxime-based organic extractant, LIX 84-I with a small volume of NH4OH. Ammoniacal solvoleaching was optimized by considering parameters such as stirring speed, time, LIX 84-I concentration, volume of aqueous ammonia, temperature and pulp density. Under the following conditions: 500 rpm, 0.3/0.3/10 (g/mL/mL) of sample/NH4OH/LIX 84-I (0.8 M), 3 h time and 25 °C temperature, quantitative Cu dissolution was achieved after two-stage solvoleaching. Cu solvoleaching followed the Avrami model, with an activation energy of 28.95 kJ/mol in the temperature range 15–45 °C (298–318 K) for the mixed control mechanism. LIX 84-I could be recycled without loss of extraction performance. Cu concentration was further enriched during stripping stage using H2SO4. A flowsheet for the sustainable metal recovery from WPCBs was developed.

Influence of Feedstock Particle Size on the Certain Determination of Chlorine and Bromine in Pyrolysis Oils from Waste Electrical and Electronic Equipment Plastics.

Rejected streams emerging from waste sorting and recycling plants are still capable of being valorized by unconventional recycling routes. This is the case of the plastic-rich fraction generated after the treatment of waste electrical and electronic equipment (WEEE). However, the material complexity of this stream supposes a handicap when it comes to obtaining repetitive results in laboratory-scale recycling processes. This work aims to highlight the influence that the pretreatment (mainly particle size reduction) of a real WEEE plastic-rich stream has on the variability of the concentration of halogens (representative pollutants) in the oils obtained from its recycling via pyrolysis. The pretreatment steps were based on the standards of the European Committee for Standardization (ECN) for the analysis of waste samples. Four samples were studied: the WEEE plastics as received; two milled samples (2 and 1 mm particle size) derived from the original one; and a simulated sample composed of virgin polymers. All the samples were treated under the same conditions: 500 °C reaction temperature, 15 °C min-1 heating rate, 30 min dwell time, and a 1 L min-1 nitrogen purge flow. The oils obtained in, at least, two pyrolysis tests performed on the same sample were deeply characterized, and the results were compared. The oils derived from the "as-received" sample showed an unacceptable relative standard deviation (RSD, ∼42%) in the chlorine concentration. The sample milled to 2 mm reduced the RSD on the concentration of chlorine in the oils down to 8%, while no enhancement in the results was observed for the further milled sample. The other two major pyrolysis fractions were also characterized, showing an overall enhancement in the RSD of the analysis of the main components of the gases, while no improvement in the solids pollutants' characterization was achieved.

Effect of Reaction Conditions on Energy Yield of Pyrolysis Gas from Apple Tree Branches.

Although the annual branches of apple trees are substantial, most of them are discarded or incinerated, resulting in a significant waste of resources and environmental pollution concerns. Therefore, it has become necessary and urgent to recycle these branches. Compared with crop straw, apple tree pruning branches exhibit a relatively elevated lignin content, which makes them an optimal feedstock for generating high-quality pyrolysis gases. Energy yield can comprehensively measure the gas production and heat value of the pyrolysis gas. Herein, the effect of reaction conditions on the energy yield of the pyrolysis gas is systematically investigated. The single-factor experimental results show that the optimal conditions are 750 °C reaction temperature, 2 °C/min heating rate, and 120 min holding time. The central composite design test of the response surface establishes that temperature has the most impact, followed by heating rate and holding time. In addition, a regression model is constructed to predict the energy yield of the pyrolysis gas. The analysis of interactions between factors indicates that factors within the lower temperature zones, higher heating rate, and shorter holding time have a more significant influence on the energy yield. These findings provide crucial guidance for the efficient production of pyrolysis gas from apple tree branches.

Insights into Activation Pathways of Recovered Carbon Black (rCB) from End-of-Life Tires (ELTs) by Potassium-Containing Agents.

This study explores the conversion of recovered carbon black (rCB) from end-of-life tires (ELTs) into activated carbons (ACs) using potassium-based activators, targeting enhanced textural properties development. The research focuses on the interaction between potassium and rCB, with the aim of understanding the underlying mechanisms of rCB activation. The study investigates several parameters of KOH activation, including the KOH/rCB mass ratio (1:3 to 1:6), activation temperatures (700-900 °C), activation time (1-4 h), and heating rate (5-13 °C/min). It also assesses the effects of different potassium salts (KCl, K2CO3, CH3COOK, and K2C2O4) on porosity and surface characteristics of the rCB/ACs. Furthermore, the role of the physical state of KOH as an activator (solid and gas-solid) was examined, alongside a comparative analysis with NaOH to evaluate the distinct effects of potassium and sodium ions. Optimal conditions were identified at an 800 °C activation temperature, a 7 °C/min heating rate, a 1:5 KOH/rCB ratio, and a 4 h activation period. X-ray diffraction analysis showed the formation of several K-phases, such as K2CO3, K2CO3·1.5H2O, K4(CO3)2·(H2O)3, KHCO3, and K2O. The effectiveness of the potassium salts was ranked as follows: KOH > K2C2O4 > CH3COOK > K2CO3 > KCl, with KOH emerging as the most effective. Notably, the gas-solid reaction of KOH/rCB was indicated as a contributor to the activation process. Additionally, it was concluded that the role of KOH in enhancing the textural properties of rCB was primarily due to the interaction of K+ ions with the graphite-like structure of rCB, compared to the effects observed with NaOH. This research introduces novel insights into the specific roles of different potassium salts and KOH activation conditions in optimizing the textural characteristics of rCB/ACs.

Tribological Properties of Spark Plasma Sintered Ti48Al48Cr2Nb2 Alloy

Ti48Al48Cr2Nb2 intermetallic alloy was studied for its tribological properties. The as-received TiAl alloy was prepared by spark plasma sintering (SPS) at 1200 °C for 5 and 7 min using 50 and 100 °C/min heating rates. Wear tests were done on the sintered TiAl under 10 N at room temperature in air. Results showed that an increase in relative density and superior microhardness led to a reduced material loss in the sample sintered for 7.5 min using a 100 °C/min heating rate. Scanning electron microscopy (SEM) images of the worn surface showed the wear widths and wear marks on the surface of TiAl alloy. The wear track width indicated the degree of wear, and the samples sintered for 7.5 min using a 100 °C/min heating rate showed improvement in wear resistance.

Impact of natural antioxidant (silybin) on the thermal stability of ultra high molecular weight polyethylene: a thermogravimetric study

The natural antioxidant (Silybin), with different concentrations, is introduced in Ultra High Molecular Weight Polyethylene (UHMWPE) and impact on thermal stability is observed. For this, thermograms are recorded at 5 ℃/min heating rate in temperature region 50–600 ℃ through Thermogravimetric Analysis (TGA) technique. The model fitting (Coats and Redfern) kinetic approach is adopted to determine activation energy of each recorded thermograms to identify optimum silybin concentration. UHMWPE, with optimum silybin concentration, are further subjected to three other heating rates (10, 15 and 20 ℃) in the same temperature region. By employing deconvolution (bi-Gaussian asymmetric function) approach, two iso-conversional kinetic models (Starink (SR) and Friedman (FR)) are utilized to obtain activation energies of the deconvoluted peaks. Further, the reaction mechanism involved in thermal decomposition, change in entropy ΔS#\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left({\\Delta \ ext{S}}^{\\#}\\right)$$\\end{document}, change in enthalpy ΔH#\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left({\\Delta \ ext{H}}^{\\#}\\right)$$\\end{document} and change in Gibbs free energy ΔG#\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left(\\Delta {\ ext{G}}^{\\#}\\right)$$\\end{document} are determined.

Potential of Miscanthus × giganteus as fuel in a suspended furnace

ABSTRACT Miscanthus is one of the potential bioenergy crops in the world. This non-woody biomass can grow almost anywhere and does not require high cultivation costs. Its energy content is approximately 525 GJ/ha/year, the highest among other non-woody biomass. This research aims to study the potency of Miscanthus × giganteus as fuel in a suspended furnace. Some combustion characteristics of Miscanthus particles were determined experimentally and numerically. At a 40°C/min heating rate, the particle's initial and active decomposition temperatures are 197 and 352°C, respectively. The study also reveals that the combustion mode of the Miscanthus particles was affected by the furnace temperature. At furnace temperatures of 300–400°C, the combustion mode of the Miscanthus particles refers to the simultaneous combustion model. While, at temperatures 450–600°C, its combustion produces extensive flames and is called the sequential combustion model. The extensive flames are useful in cyclone furnaces to maintain combustion stability. Under cold modelling, the average drag time of the representative particles with an equivalent diameter of 1384 µm, in a typical furnace, is 26.82 s, much higher than its combustion time of 11.25 s. This indicates that the particles can be burned out in a suspended state.

Fast-drying of red ceramics: A new evaluating approach based on the combined use of optical dilatometry and thermogravimetric analysis

This study aimed to evaluate the effects of composition and heating rate on the fast-drying (∼60 min) of red ceramics obtained by extrusion using optical dilatometry and thermogravimetry to obtain the drying curve. Three different plastic clays were used in the four formulations investigated, as well as three heating rates with a total time of 60 min and a maximum drying temperature of 200 °C: 5.83, 3.89, and 2.92 °C/min. Based on the results obtained from the modified Bigot curves, a fast-drying curve (3 °C/min) was established in a static laboratory dryer with a total cycle of 60 min and a maximum temperature of 160 °C. The samples were characterised in terms of compressive resistance and visual aspects related to drying cracks. Formulation F5, containing 50 wt% AM clay and 50 wt% AV clay, exhibited the worst performance in fast-drying with drying cracks, whereas formulation F7, containing 33.3 wt% AC clay, 33.3 wt% AM clay and 33.3 wt% AV clay, exhibited the best performance. Formulations F7 and F8 (16.7 wt% of AC clay, 66.6 wt% of AM clay and 16.7 wt% of AV clay) were fired at 900 °C in an electric kiln, with a heating rate of 1.5 °C/min and a 2 h holding time, and then characterised in terms of firing shrinkage, water absorption and compressive strength. The results showed that Formulation F7 presented suitable behaviour in the fast-drying process at 160 °C for 60 min in a laboratory dryer at a heating rate of 3 °C/min, 0.9 wt% a residual moisture. It exhibited no drying cracks and a dry compressive strength of 0.94 ± 0.09 MPa. However, the combined analysis of optical dilatometry and thermogravimetry indicated that the drying conditions could be optimised for a residual moisture of 2 wt%, using a thermal cycle of 138 °C for 19 min (heating rate of 5.83 °C/min) if adequate control of the humidity of the chamber atmosphere in the first drying stage is employed to avoid drying cracks. The results also showed that the specimens of formulations F7 and F8 met the technological requirements defined by the Brazilian standard ABNT NBR 15270-1, demonstrating the feasibility of producing red ceramic bricks by extrusion with fast-drying. The combined optical dilatometry and thermogravimetry techniques used to obtain the Bigot curve applied to fast-drying showed very good agreement with those obtained in the laboratory dryer. These combined techniques represent promising approaches for studying the fast-drying of red ceramics.

Implementation of Taguchi method, ANOVA and regression analyses to enhance char yield by carbonization in lignite-biomass blended

ABSTRACT Energy is a basic need for modern societies. Renewable energy refers to producing and using energy without harming the environment and without consuming resources. The transition to renewable and sustainable energy can provide many environmental, economic and social benefits. Academic research plays an important role in achieving this transition. Sustainable energy is critical to protecting the environment, promoting economic development and supporting social improvements. The transition to sustainable energy is a necessity for the future of humanity. For this purpose, in this study, lignite and biomass (apricot kernel shell) carbonization experiments were carried out under different conditions. Mixing ratio (Lignite/Biomass (w/w 1:1, 1:2, 1:3)), temperature (400°C, 500°C, 600°C) and heating rate (10°C/min, 30°C/min, 50°C/min) were determined as variable parameters. Taguchi’s experimental design was used to optimize the parameters. The orthogonal array design plan was determined as L9 according to the available variables (33 x 33). Since the study aimed to obtain clean solid fuel, char yields were taken into account from the results. Signal-to-noise (S/N) ratios were calculated based on the larger the better condition. As a result of the carbonization experiments performed under Taguchi optimization conditions, it was determined that the S/N ratio was 31.73 and the char yield was 40.19%. Since the estimated char yield with the Taguchi method was 38.85%, it was concluded that the optimization was achieved with 96.67% accuracy. The test parameters satisfying these conditions were determined as 1:1 lignite/biomass mixing ratio, 400°C temperature and 30°C/min heating rate. As a result of the ANOVA analysis, it was seen that the heating rate did not have a significant effect on these parameters. In contrast, the temperature and mixing ratio were important variables. Also, regression analysis (linear and quadratic) was used in this study to calculate the equations for the prediction of char yield. It was concluded that the linear regression model was more successful in estimating the char yield.

Influence of Cobalt content on the microstructure and texture evolution of hot-press sintered Tungsten nickel copper Alloy (W-Ni-Cu)

This study examines the effect of cobalt on the crystallographic texture and grain boundary evolution of hot-press sintered tungsten heavy alloy (W-4.9Ni-2.1Cu). Traditional tungsten heavy alloy with a Ni:Cu ratio of 7:3 has cobalt added (i.e., cobalt content increased from 0 to 1 wt% with a 0.25 wt% interval). The samples were produced using the hot press sintering method with the following parameters: 50 MPa pressure, 10 °C/min heating rate, 1450 °C temperature, and a 20-min hold time. The unalloyed cobalt WHA compact has a fibre texture in the (001) plane that is aligned in the 〈111〉 orientation. In addition, the cobalt-alloyed WHAs compacts exhibit a lower proportion of grain boundaries with low angles. Enhanced solid solution formation between cobalt and WHAs during liquid phase sintering led to increased compacts densification and randomised weak fibre development in cobalt-alloyed compacts. Texture deterioration (001) <111> in cobalt-added WHAs is caused predominantly by substructural recovery during liquid phase sintering. This study indicates that the addition of cobalt to the stoichiometry of WHAs resulted in the homogenous distribution of binder matrix within the compact during sintering. As a result, the W-4.9Ni-2.1Cu-1Co alloy exhibited improved microhardness (429.5 HV0.5), electrical conductivity (23.34% of IACS), and relative density (98.10%).

Effect of Mn addition in W-Ni-Cu heavy alloy processed through hot press sintering techniques on microstructure, microtexture and grain boundary character evolution

In this current study, the impact of manganese addition to 93 W-4.9Ni-2.1Cu-xMn (where x = 1, 2, 3, and 4 Wt%) on the microstructure, texture development, and grain boundary character distribution of tungsten heavy alloy (WHAs) was examined. The samples were produced through a vacuum hot press sintering, with parameters 50 MPa pressure, 10 °C/min heating rate, and 1450 °C sintering temperature for 20 min holding duration. To study the influence of manganese on the texture development and microstructure in conventional WHAs, electron backscatter diffraction (EBSD) was employed. The important findings from the EBSD analysis reveal that fibre texture (001) 〈111〉 and a higher fraction of low-angle grain boundaries in the Mn unalloyed compact resulted from extensive atomic jumps between the particles at elevated temperatures. Further texture analysis on the Mn-added compacts reveals that manganese oxide (MnO) formation during liquid phase sintering led to lower densification and randomized weak fibre texture development in manganese-alloyed compacts. In addition, the texture degradation in Mn-added compacts is mainly caused by recrystallization followed by sub-structural recovery during liquid phase sintering. This study indicates that increasing manganese content in WHAs stoichiometry led to a heterogeneous distribution of binder matrix (NiCu) in the sintered compact. As a result, W-4.9Ni-2.1Cu-4Mn alloy revealed decreased relative density (90.70%), microhardness (389.5 HV0.5), and electrical conductivity (15.74% of IACS).

Electrochemical Property of Activated Carbon Monolith from Potato for Supercapacitor Electrode

Electrochemical property of activated carbon monolith from potato was studied for possible application in supercapactor electrode. First, potato powder was purchased and used to prepare column shape samples via pressing. Then, they were subjected to two-step pyrolysis to avoid cracking, such as the 1st step at 300 °C at 0.5 °C/min heating rate and the 2nd pyrolysis at 400, 500 or 600 °C under N2 flow in a tube furnace. Next, the samples were cut into 1 mm thickness and then grinded into 0.5 mm, followed by immersing in 6M KOH solution and then the activation at 700 °C under N2 flow. Finally, the electrochemical properties of activated carbon monoliths were evaluated with a three-electrode system by cyclic voltammetry, galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). In addition, two-electrode system was also studied with the samples having highest specific capacitances, being from 400 °C pyrolysis. The samples were characterized by Raman, XRD, XPS and SEM, and specific surface area was also measured. Specific capacitance of 382 F/g was obtained from 400 °C pyrolysis, followed by 321 and 253 F/g from 500 and 600 pyrolysis, respectively.

Co-disposal kinetics and characteristics of sewage sludge and municipal solid waste incineration fly ash

Sewage sludge (SS) and municipal solid waste incineration fly ash (MSWIFA) have characteristics of high yield, scattered distribution, and strong harm. Co-disposal of SS and MSWIFA in the existing cement kilns is a prospective way to deal with these two types of solid waste. In this study, the pyrolysis kinetic, thermogravimetric analysis, heat and mass transfer characteristics and pollutant release during SS and MSWIFA co-disposal were investigated through a series of experiments and simulations. In the experiment, pulverized coal (PC) was used as fuel to imitate the real environment of a cement kiln. According to the results, the interaction of the two solid wastes was observed mainly during the devolatilization and combustion periods. At an average blending ratio (60%) and 25 ℃/min heating rate, the blend actual mass loss rate has the largest difference compared to the linearly calculated mass loss rate (0.74%/min), with higher comprehensive combustion characteristic index (3.54), and the blends have better overall heat transfer, internally converging to 350 K. Meanwhile, when SS proportion in PC-SS-MSWIFA is between 20% and 30%, the emission concentration of SO2 and NO was low, and it has good environmental benefits. This research aims to offer theoretical support for the co-disposal of SS and MSWIFA.

Co-Pyrolysis of walnut shell and waste tire with a focus on bio-oil yield quantity and quality

In this study, a series of pyrolysis and co-pyrolysis experiments on waste tires and walnut shells were conducted under ideal conditions of 500 °C, 10 °C/min heating rate, and 60 min of retention time. Mixture samples with WS/WT: 3/1, 2/2, and 1/3 additive ratios were utilized in co-pyrolysis experiments. The results of the experiments showed that the WS/WT: 3/1 additive ratio samples were necessary to achieve the positive synergistic effect. A 52.57 ± 0.28 % efficient liquid product by mass was produced under these conditions on a dry, ashless basis, which has a significant production potential for the production of high pyrolytic oil. The co-pyrolytic organic phase of the fuel contains around 40 % light naphtha, 10 % heavy naphtha, and 30 % medium distillate by volume, according to atmospheric distillation experiments. Furthermore, it has been discovered that this product can be utilized as a gasoline or gasoline additive due to its IBP-72 °C boiling point range, 20 % distillate percentage, and immediate or inexpensive improvement. When these observations are taken into consideration, it is clear that the co-pyrolytic liquid can be utilized as a raw material input in the production of various of commercial liquid fuels as well as a variety of chemicals with high added value.

Comparison of Ca-Based Commercial and Natural Catalysts Performance on Olive Pomace Pyrolysis Process

Physicochemical treatment was applied with 20 mg/L alum to the marble processing effluents as 5 minutes 200 rpm mixing, 25 minutes 15 rpm mixing and 60 minutes settling and marble sludge (MS) was produced. Catalytic performance of MS in olive pomace (OP) pyrolysis process was evaluated and compared to commercial Ca(OH)2 since it mainly comprises of different AAEMs (especially Ca and its forms such as CaCO3, CaO) functioned as catalyst. Catalytic pyrolysis was conducted at 600°C and 5°C/min heating rate with 5% and 10% catalyst (MS or Ca(OH)2) dosages. Although both catalysts had important effect on pyrolysis product yields, Ca(OH)2 was found as good alternative for higher gas production and MS was introduced as better option for the higher char production comparing to the conventional OP pyrolysis. Pyrolysis biochars produced with MS were in higher thermal strength than the biochars generated with Ca(OH)2. Moreover, biooils of OP+MS include different organic compounds, such as 9 heptadecanol, 1-eicosanol, ethyl linoleate, ethyl oleate, addition to the compounds observed in pyrolysis liquids of OP and OP+ Ca(OH)2. All detected organic components have diverse usage areas. Ca(OH)2 provided more decrement in the percentages of oxygenated compounds as compared to the MS. Consequently, it can be stated that MS can be used successfully as an alternative to Ca-based commercial catalyst in OP pyrolysis.

Effects of green and innovative pretreatment techniques on kinetic parameters of sunflower seed husk

The effects of green pretreatment processes, such as ultrasonic process (US) and deep eutectic solvent (DES), applied to the biomass on kinetic parameters are as important as their effects on characteristic properties. Process conditions and course of reaction progression depend on the knowledge about kinetic parameters, activation energy and reaction model of thermal degradation in scale-up studies. Therefore, in this study, the change in the kinetic parameters with US applied with both distilled water and DES (glycerol:sodium acetate) at 100 W power and 20 kHz frequency for 10 minutes to sunflower seed husk (SSH) was revelaed. Isoconversional methods Kissinger-Akahira-Sunose (KAS) and Flynn- Wall-Ozawa (FWO) were preferred for the evaluation of activation energy of SSH and pretreated SSH at 15°C/min, 20°C/min and 25°C/min heating rates. US pretreatment with DES instead of water resulted in increment of average activation energy values (Ea) from 113.13 to 143.65 kJ/mol in the KAS method. Ea values for all SSH samples changed in the range of 87.72-143.65 kJ/mol and higher Ea values was obtained with KAS method for pretreated SSH samples. Consequently, the use of DES in US pretreatment was more effective to change kinetic parameters of SSH compared to water.

Effect of final temperature and heating rate on the mechanical and optical properties of a zirconia veneering ceramic

PurposeTo evaluate the effect of firing temperature and heating rate on the volumetric shrinkage, translucency, flexural strength, hardness, and fracture toughness of a zirconia veneering ceramic. Material and methodsZirconia veneering ceramic specimens (N = 45) with varying final temperatures (730 °C, 750 °C, and 770 °C) and heating rates (70 °C/min, 55 °C/min, and 40 °C/min) were fabricated (n = 5). Each specimen's shrinkage, translucency, flexural strength, hardness, and fracture toughness were determined. Two-way analysis of variance, Scheffé test, and Pearson's correlation analysis were used to evaluate data (α = 0.05). ResultsThe shrinkage (44.9 ± 3.1–47.5 ± 1.6 vol%) and flexural strength (74.1 ± 17.4–107.0 ± 27.1 MPa) were not affected by tested parameters (P ≥ 0.288). The interaction between the main factors affected the translucency, hardness, and fracture toughness of the specimens (P ≤ 0.007). Specimens with 770 °C final temperature and 70 °C/min heating rate had the lowest (21.8 ± 3.2 %) translucency (P ≤ 0.039). The hardness ranged between 4.98 ± 0.51 GPa (730 °C; 70 °C/min) and 5.60 ± 0.37 GPa (770 °C; 70 °C/min). Fracture toughness ranged between 0.54 ± 0.04 MPa√m and 0.67 ± 0.08 MPa√m with the highest values for specimens fired at 730 °C with 70 °C/min (P ≤ 0.001). There was a positive correlation between translucency and hardness (r = 0.335, P = 0.012), and a negative correlation between fracture toughness and all parameters other than shrinkage (translucency: r = −0.693/P < 0.001, flexural strength: r = −0.258/P = 0.046, hardness: r = −0.457/P < 0.001). ConclusionsHeating rate and final temperature should be considered while fabricating veneered zirconia restorations with tested ceramic as they affected the translucency, hardness, and fracture toughness.

The facile production of Fe2O3-biochar electrocatalyst for methanol oxidation reaction

In this study, the facile-green method was applied for the production of electroactive composite anode material. For this purpose, biochar was produced via pyrolysis of Pinus nigra (PN) sawdust in a stainless-steel reactor at 300, 400 and 500 °C with 10 °C/min heating rate. The Fe2O3 particles were fabricated via the green synthesis method. The Fe2O3-biochar electrocatalyst was operated on Ni foam electrode and the potential application as an anode for methanol fuel cell was investigated in an alkaline medium. Field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Brunauer-Emmett-Teller analysis (BET), and attenuated total reflectance Fourier transform infrared spectroscopy (FTIR/ATR) were used to characterize the morphology of the electrocatalyst samples. The electrochemical measurements of electrocatalyst samples were achieved via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and chronoamperometry (CA). The enlarged surface area of biochar enabled the formation of more electroactive sites for methanol electrooxidation and favorable structures of biochar could support to increased electrocatalytic activity of catalysts for methanol oxidation and produce favorable matrices for Fe2O3 loading. The obtained results demonstrate that the electrooxidation of methanol occurred at 0.36 V. The favorable structures of biochar acted as a support, enhancing the electrocatalytic activity of Fe2O3 for methanol oxidation. The electrocatalyst demonstrated remarkable activity with almost 4 A g−1 current density at 0.55 V. The Rct values were 0.73 Ω and 0.45 Ω at 0.55 V, for Ni foam and Ni foam/Fe2O3-biochar, respectively. Long-term measurements demonstrated that the Ni foam/Fe2O3-biochar catalysts was remarkably stable, with a 4 % difference in current before and after the CA analysis.