Thermal Treatment Temperature Research Articles

Characterization of a Food‐Safe Colorimetric Indicator Based on Black Rice Anthocyanin/PET Films for Visual Analysis of Fish Spoilage

ABSTRACTThe safety of food products is of prime importance for consumers and manufacturers. Many means can be used to validate a food product's safety before it is consumed. This study is about the preparation, characterization and evaluation of a generally recognized as safe (GRAS) sensitive colorimetric sensor that detects volatile gases (TVB‐N) resulting from fish spoilage, thus indicating the pH variation of packaged fish products. This is performed by coating a thin layer of ink sensors on the surface of the supporting matrix (corona‐treated PET). Various visual pH indicators were prepared based on black rice anthocyanin as an FDA‐approved dye. Black rice, which contains more than 80% cyanidin‐3‐glucoside, is the most prevalent anthocyanin component. Because of its low toxicity and high concentration, it can be utilized as a natural food colourant. pH indicators based on black rice can show distinct colours in various pH: from red (low pH) to violet (4–6) and deep purple/blue (6–7), blue (7–9) to yellowish/light brown (9–13) throughout the acid–base reaction by the analyte. The ink formulation was prepared by incorporating a binder system (PVOH‐PEG) for higher surface wettability, a crosslinking agent (citric acid) for higher adhesion, an antifoaming agent (natural vanillin) and acetic acid as a pH fixing agent. Corona treatments affected substrate surface chemistry in this study. The samples with thermal treatment passed the ASTM D3330 tape test, the 8000 passages for dry sponge and the 25 passages for wet sponge through the abrasion method. Anthocyanin concentration in formulated ink based on calculation by UV–vis spectra is 0.240 mg/100 g. Sensitivity tests towards TVB‐N gases were carried out at a temperature of 4°C to evaluate the performance of colorimetric films with formulated ink along with thermal treatment (temperature: 165°C, time: 5 min) using the volatile gases emitted by the fish sample inside the package.

Seedling Emergence and Growth Can Be Improved by Char Carbon Created During Thermal Treatment of Petroleum-Impacted Soils

ABSTRACT Thermal treatment of soils to remove petroleum hydrocarbons alters soil properties in ways that limit germination potential for plants used in revegetation efforts. However, recent studies have shown that a char material with the potential to offset fertility-reducing effects is produced by the pyrolysis of hydrocarbons during treatment. In this study, seedling emergence and growth (14 days) of two plant species, soybean (Glycine max) and oat (Avena sativa), were evaluated in four soils of contrasting properties treated with 5% (by mass) oil addition and two levels of salt addition. Three temperatures (300, 425, and 550°C) of thermal desorption (TD) and one smolder remediation approach were employed to remove the oil prior to planting. Results indicate that seedling response to temperature of thermal treatment and salt addition is dependent both upon plant species and soil properties. Higher temperatures were necessary to remove crude oil to levels low enough to allow germination. The smoldering approach did not remove enough oil to allow germination. This is the first study to show that early shoot mass and root mass are improved following TD treatment compared with an untreated control under certain conditions. The outcomes will be valuable for designing TD treatments when revegetation is the goal.

Temperature regulated Fe3Si@SiC@carbon core-shell structure with high-performance microwave absorption

Developing high-performance microwave absorbing materials (MAMs) to address the electromagnetic wave pollution is still a huge challenge. Multi-interface core-shell structure with magnetic and dielectric loss components have been attracting extensive attention as MAMs for the enhanced interfacial polarization and impedance matching. In this work, magnetic loss core and dielectric loss bi-shell structure Fe3Si@SiC@C (FSC) composite was synthesized through hydrothermal, self-polymerizing coating and high temperature thermolysis. The thermal treatment temperature has a great effect on the morphology structure and electromagnetic properties of FSC. The results indicated that the FSC exhibited an effective absorption bandwidth (EAB) of 4.24 GHz at a thickness of 1.4 mm, and an EAB of 12.4 GHz with the absorber thickness varied from 1 mm to 3 mm. Furthermore, the microwave attenuation mechanism of the FSC composite were investigated in detail. The integration of magnetic core with multiple dielectric shells provides a design deliberation and reference for further high-performance MAMs fabrication.

Determination of Wax Deposition Rate Model of Blended Oils with Different Blending Ratios

Blending with light oil is a commonly used and reliable method of crude oil transportation, and the blending ratio is a crucial operating parameter in determining the safe and efficient operation of the pipeline. In this paper, in-house flow and deposition experiments are used to evaluate the flow and deposition characteristics of crude oils with varying blending ratios. The results show that (1) blending with light oil basically does not affect the shape of the DSC curve of crude oil; (2) blending with light oil will not eliminate the thermal treatment effect, and the mixed oil flowability still remains highly dependent on the thermal treatment temperature; (3) blending with light oil can greatly decrease the abnormal point and oil viscosity, in which the low-temperature viscosity decreases more significantly; and (4) a wax deposition model of mixed oil is obtained through the fitting of Huang’s model, where the blending ratio is a crucial factor in the determination of the model parameters k, m, and n.

Fabrication of polydopamine/rGO Membranes for Effective Radionuclide Removal.

In this work, a novel polydopamine/reduced graphene oxide (PDA/rGO) nanofiltration membrane was prepared to efficiently and stably remove radioactive strontium ions under an alkaline environment. Through the incorporation of PDA and thermal reduction treatment, not only has the interlayer spacing of graphene oxide (GO) nanosheets been appropriately regulated but also an improved antiswelling property has been achieved. The dosage of GO, reaction time with PDA, mass ratio of PDA to GO, and thermal treatment temperature have been optimized to achieve a high-performance PDA/rGO membrane. The resultant PDA/rGO composite membrane has exhibited excellent long-term stability at pH 11 and maintains a steady strontium rejection of over 90%. Moreover, the separation mechanism of the PDA/rGO membrane has been systematically investigated and determined to be a synergistic effect of charge repulsion and size exclusion. Results have indicated that PDA/rGO could be considered as a promising candidate for the separation of Sr2+ ions from nuclear industry wastewater.

A micro–macro model evaluating thermal treatment temperature effect on compressive failure of brittle rocks

A micro–macro model evaluating thermal treatment temperature effect on compressive failure of brittle rocks

Effects of heated-treating temperature on the stability and electrochemical performance of alginate-based multi-crosslinked biomembranes

In this study, the organosilane nanoparticles as additive and crosslinker were prepared and incorporated into sodium alginate to fabricate a series of alginate-based multi-crosslinked biomembranes at different thermal treatment temperature without the usage of another crosslinking agent. The effects of treatment temperature on the stability of biomembranes including dimensional, oxidative, hydrolytic and mechanical stability were investigated in detail. As a whole, the stability of biomembranes exhibited increasing tendency with the increment of treatment temperature due to the formation of more compact internal network structure. The electrochemical performance of biomembranes in respect to their potential as proton exchange membranes for direct methanol fuel cell application were also investigated based on the treatment temperature. The results revealed that the biomembranes possessed excellent methanol resistance and the methanol diffusion coefficient decreased with the increment of treatment temperature. The biomembrane with 120 °C heat-treatment showed the optimal selectivity (14.30 × 105 Ss cm−3), which was about 1.77 and 68.10 times of that and of M-80 (8.09 × 105 Ss cm−3) and Nafion@117 (0.21 × 105 Ss cm−3), respectively. Fuel cell performance measurements showed that M-120 possessed higher maximum power density and cell stability compared with M-80 and Nafion@117, indicating its best adaptability for use in direct methanol fuel cell.

Experimental Study on the Evolution Law of the Mechanical and Pore Characteristic Parameters of Set Cement under High- and Ultra-High-Temperature Treatments

Cement has been widely used as a structural material in many underground projects, and these projects often face high- or ultra-high-temperature environments, leading to the deterioration of the mechanical, porosity, and permeability properties of set cement, thereby increasing the risk of instability of underground structures. In response to this, two new temperature-resistant cement slurry systems were designed. Experiments were conducted on the changes in porosity and permeability of set cement after thermal treatment using low-field nuclear magnetic resonance technology (NMR), visual studies of pore and crack development were carried out using the argon-ion polishing field emission scanning electron microscopy (FE-SEM) and computed tomography (CT) methods. The research results show that as the thermal treatment temperature continued to rise, the compressive strength first increased (25 °C–200 °C) and then decreased (200 °C–600 °C). The porosity of the set cement first decreased (25 °C–115 °C) and then increased (115 °C–600 °C), and the penetration first slowly increased (25 °C–400 °C) and then rapidly increased (400 °C–600 °C). Visualization experiments were conducted on micro-cracks and the pore distribution of the set cement under high- and ultra-high-temperatures, which proved the evolution law of these characteristic parameters. The research results have vital reference significance for the protection of the structural stability of cement components when encountering high-temperature environments.

The influence of the coprecipitation synthesis methods on photodegradation efficiency of ZnFe based photocatalysts

Organic dye pollutants that are progressively used in modern chemical industries, emerged as a major source of water contamination. A promising eco-friendly and simple approach to water purification is the heterogeneous photocatalytic process that utilizes various metal oxide semiconductors in the presence of light, initiating oxidation-reduction reactions resulting in dye degradation. The aim of this study was to investigate the influence of coprecipitation synthesis methods on photodegradation efficiency. The ZnFe based photocatalysts were synthesized using two different methods: low (LS) supersaturation and high (HS) supersaturation coprecipitation and thermally activated at 100, 300, 500 and 700?C. Structural and textural characterisation were carried out and their efficiency in methylene blue photodegradation test reaction was studied. LS samples treated at 100 and 300?C exhibited very low photodegradation efficiency (less than 10 %) when compared to HS samples treated at the same temperatures (75 and 85 %). The efficiency of LS 500 and LS 700 samples improved (67 and 75 %) with the increase in thermal treatment temperature and the photodegradation efficiency difference between LS and HS samples decreased. Such behaviour of LS and HS samples could be explained with structural and textural properties that originated from different synthesis methods.

Effect of thermal modification on axial compression properties and hardness of laminated bamboo

Vacuum thermal modification is an environmentally friendly method to improve the durability and reduce insect infestation of bamboo, which has the advantages of preventing deformation, preventing oxidation of the bamboo surface, and uniformity of thermal conductivity compared to previous studies that used mediums such as nitrogen, air, or oil for heating. This study thermally modified laminated bamboo materials for 1 to 5 h under vacuum conditions ranging from 170 to 230 °C and evaluated their microstructure, surface hardness, water absorption, and axial compression mechanical properties. The results showed that compared with untreated laminated bamboo timber, the colour gradually deepened as the temperature and time of heat treatment increased, while the equilibrium moisture content of heat-treated laminated bamboo timber was reduced by about 4–27% and the density by about 11–18%. This phenomenon indicates that the cell walls of laminated bamboo become denser with increasing temperature, which leads to a significant decrease in the hygroscopicity of laminated bamboo. The dimensional stability of the material was improved. Regarding the macroscopic axial compression test, the results showed that the thermal modification treatment significantly increased the axial compression strength of laminated bamboo, and this improvement in mechanical properties was inversely related to the heat treatment temperature. In addition, through the nanoindentation test, we found that the laminated bamboo's surface hardness and modulus of elasticity showed an inflexion point when the treatment temperature reached 210 °C, indicating that the material properties changed significantly in this temperature range. Investigating the response mechanism between the temperature and time of vacuum thermal heat treatment and the mechanical properties of bamboo will contribute to the development or optimization of the thermal modification process, leading to materials with excellent properties and broadening the application areas.

Effective disposal of hazardous waste from non-ferrous waste recycling through thermal treatment

Hazardous wastes containing non-ferrous metals have significant value in recycling. However, the recycling process generates leaching residues (HWLR) with high levels of heavy metals, posing a risk to the environment. Based on the component characteristics of HWLR, silica residue (SR), and silicon tetrachloride cracking slag (STCS), the feasibility of co-thermal treatment for the efficient disposal of HWLR, SR and STCS was verified in this study. According to the SiO2–Na2O–CaO ternary system diagram, the melting point of the system decreases gradually with the appropriate increase in SiO2 content when the CaO/Na2O ratio in the system was determined to be about 2.33. When the theoretical liquid phase content of the mixed system of 100%, the thermal treatment temperature could be lowered to 1100 °C, which is significantly below the melting points of HWLR, SR, and STCS individually. The experimental results confirmed that thermal treatment at temperatures above 1000 °C effectively eliminated the leaching toxicity of Cu, Ni, Zn, Cr, Cd, and Pb in the mixed samples of HWLR, SR, and STCS, which can mainly be attributed to the formation of a glass network structure during the thermal treatment process. This study demonstrated that low-temperature melting treatments could efficiently and thoroughly solidify heavy metals in HWLR, SR, and STCS.

Structural properties and failure characteristics of granite after thermal treatment and water cooling

In a variety of fields such as exploitation of geothermal energy and the reconstruction of nuclear waste storage, both of high-temperature and cooling process change the physical and mechanical properties of granite. Uniaxial compression tests were performed on five groups of granite samples at 25 °C, 200 °C, 400 °C, 600 °C and 800 °C after water cooling, and CT scanning, acoustic emission(AE) monitoring and X-ray diffraction(XRD) scanning were used to investigate the structure properties and failure characteristics of granite. It is found that the proportions of pore volume greater than 106 μm3 and less than 105 μm3 with are positively and negatively correlated with the thermal treatment temperature respectively. The mechanical properties of granite are significantly deteriorated by temperature gradient shock, and crack development scale during failure process overall increases as implied by AE response. The failure intensity index η is proposed to characterize the failure severity of granite, and the value of η descends with the increase of thermal treatment temperature, indicating the failure severity of granite is alleviated. Three types of loading failure mode are classified for water-cooled high-temperature granite. The failure mode of granite at 200 °C and 600 °C is tensile failure and tensile-shear failure respectively, while the granite samples are dominated by shear failure at 25 °C, 400 °C and 800 °C.

Synthesis and characterization of B-type carbonated hydroxyapatite materials: Effect of carbonate content on mechanical strength and in vitro degradation

The current approach in bone tissue engineering requires resorbable biomaterials that enhance bone formation while maintaining sufficient mechanical stability. In this work, the influence of three levels of B-type carbonate substitution in hydroxyapatite lattice on mechanical strength and degradation rate is analyzed. The inverse aqueous route has been selected as a synthesis method of four powders with carbonate substitution between 4 and 6wt.%. X-ray fluorescence (XRF), (C-S)-Analysis, FT-Infrared, X-ray diffraction, DTA-TG and TEM were used to investigate chemical composition, type of substitution, thermal behaviour, and morphology of the powders. Disc shaped specimens were processed by uniaxial pressing and sintering in argon/CO2 flow. Maximum temperatures of thermal treatment between 750 and 850°C were selected to obtain similar porosity levels for the different compositions. The highest carbonate substituted material (5.3wt.%) presented higher compressive strength and dissolution rate than the other materials showing the beneficial effect of B-type substitution in hydroxyapatite materials for bone repair.

Effect of high-dose electron beam irradiation on thermal decomposition behavior of polytetrafluoroethylene (PTFE)

In this study, we investigated the effect of high-dose (>10.0 MGy) irradiation on polytetrafluoroethylene (PTFE) decomposition in the presence of oxygen. To this end, we analyzed the chemical structures of PTFE residues after irradiation and thermal treatment as well as the outgas components during thermal treatment at 50 °C intervals. Thermogravimetric analyses indicated that the residual PTFE powder exhibited an initial decomposition (5% weight loss) at 159 °C, which is 365 °C lower than that of the original unirradiated sample. The initial decomposition temperature decreased at up to 5 MGy and gradually leveled off at above 140 °C. Fourier transform infrared (FT-IR) spectroscopy analysis of the residual PTFE powders indicated that the contents of thermal decomposition at lower temperature ranges were qualitatively related to the extent of the formation of oxidizable PTFE components, such as carbonyl groups. The formation of these components increased as the absorbed doses increased. The oxidized components gradually decreased with increasing thermal treatment temperature and tended to disappear at 470 °C. This demonstrated the effect of the oxidized compounds in the irradiated PTFE on lower temperature decomposition. The analysis of the gas components resulting from the thermal decomposition of the PTFE residuals revealed more detailed chemical information concerning the oxidative components of the irradiated PTFE. At temperatures below 420 °C, approximately 30% of the PTFE residue underwent pyrolysis to yield oxidized fluorocarbon products (CxFyOz) and further decomposed products (CO2). The remaining 70% of the residue thermally decomposed at temperatures above 420 °C, yielding monomer-related products such as C2F4, C3F6, and C4F8. These were identical to the gas products resulting from the thermal degradation of the original PTFE in the same temperature range. These results are indicative of the possibility of recycling and reusing fluorocarbons during irradiation.

Synergistic advancements in sewage-driven microbial fuel cells: novel carbon nanotube cathodes and biomass-derived anodes for efficient renewable energy generation and wastewater treatment

Microbial fuel cells (MFCs) offer a dual solution of generating electrical energy from organic pollutants-laden wastewater while treating it. This study focuses on enhancing MFC performance through innovative electrode design. Three-dimensional (3D) anodes, created from corncobs and mango seeds via controlled graphitization, achieved remarkable power densities. The newly developed electrode configurations were evaluated within sewage wastewater-driven MFCs without the introduction of external microorganisms or prior treatment of the wastewater. At 1,000°C and 1,100°C graphitization temperatures, corncob and mango seed anodes produced 1,963 and 2,171 mW/m2, respectively, nearly 20 times higher than conventional carbon cloth and paper anodes. An advanced cathode composed of an activated carbon-carbon nanotube composite was introduced, rivaling expensive platinum-based cathodes. By optimizing the thermal treatment temperature and carbon nanotube content of the proposed cathode, comparable or superior performance to standard Pt/C commercial cathodes was achieved. Specifically, MFCs assembled with corncob anode with the proposed and standard Pt/C cathodes reached power densities of 1,963.1 and 2,178.6 mW/m2, respectively. Similarly, when utilizing graphitized mango seeds at 1,100°C, power densities of 2,171 and 2,151 mW/m2 were achieved for the new and standard cathodes, respectively. Furthermore, in continuous operation with a flow rate of 2 L/h, impressive chemical oxygen demand (COD) removal rates of 77% and 85% were achieved with corncob and mango seed anodes, respectively. This work highlights the significance of electrode design for enhancing MFC efficiency in electricity generation and wastewater treatment.

Elucidating influences of defects and thermal treatments on CO2 capture of a Zr-based metal–organic framework

Carbon capture and storage (CCS) technology is currently an essential response to the global warming problem caused by excessive CO2 emissions. Efficient and reproducible adsorbents for flue gas treatment play an important role in CCS technology, and metal–organic frameworks (MOFs) are considered to be ideal candidates by virtue of their designable CO2 sorption sites. However, carbon capture performance evaluation and reproducibility of MOFs still hinder their application promotion in industrial production. In this work, an extended UiO-66-type MOF based on 1,4-naphthalenedicarboxylate, was successfully synthesized in both a near defect-free form (UiO-66N) and a defect-rich form (DUiO-66N), for exploring the influence of crystalline defects and thermal treatments on carbon capture performance. Although powder X-ray diffraction showed that UiO-66N and DUiO-66N possessed the same crystalline phase, transmission electron microscopy, thermalgravimetric analyse and gas/dye sorption confirmed the presence of crystalline defects and the variation of porosity in DUiO-66N. CO2 sorption isotherms and flue gas breakthrough experiments revealed the defect-induced improved carbon capture performance, which was also supported by density functional theory. Meanwhile, the metastability of defects required low thermal treatment temperatures for activation and regeneration thus maintaining the superior carbon capture performance. These findings suggested that in reproducing and evaluating the carbon capture performance of MOFs, it cannot rely only on the global crystalline phase judgment, but needs to identify the local fine structure as well as optimize activation and regeneration conditions.

Surface morphology of magnetic carbon foam regulated electromagnetic properties for microwave absorption

Electromagnetic pollution resulting from the electronic communication can be mitigated by using microwave absorbers. The magnetic N-doped carbon foams with diverse surface morphologies as absorbers were synthesized via alkalization treatment, hydrothermal reaction, and carbothermic reduction reaction. The microstructure, electromagnetic parameters, and microwave absorption properties can be tailored by adjusting thermal treatment temperatures. The results indicated that the composites exhibit exceptional microwave absorption properties, with a minimum reflection loss of −44.15 dB at 11.18 GHz and an effective absorption bandwidth of 5.3 GHz at a thickness of 1.53 mm. The exceptional microwave absorption properties can be attributed to the synergistic effect of superior impedance matching, robust dielectric loss, and magnetic loss. The far-field radar cross section (RCS) is also reduced, achieving a maximum RCS reduction value of 14.6 dBm2. The present study presents a novel concept for the fabrication of lightweight and broadband microwave absorbing materials.

Iron ions embedded in hexagonal mesoporous silica via a simple method: implementation in mild oxidation catalysis

AbstractMesoporous silica monoliths containing dispersed FeIII sites have been prepared following a direct and simple synthetic method. The iron‐containing materials are able to catalyze the epoxidation of cyclooctene by H2O2 under mild conditions. Textural and spectrophotometric analyses reveal that, when the thermal treatment temperature of the materials increases (from 500 °C to 1000 °C), the pore diameter of the silica matrix decreases while the formation of small oxo‐iron(III) clusters is promoted. Among the five materials obtained after treatment at 500, 700, 800, 900 or 1000 °C, the one prepared at 700 °C exhibits the best catalytic performances. This indicates that a compromise must be found between several parameters, such as the pore size (which decreases with calcination temperature) and the hydrophobicity of the channel surface (which is favored at higher temperature), for an optimal reactivity.

Color adjustable CsPbX3 (X=Cl, Br, I) perovskite quantum dots germanate glass

CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) have attracted extensive attention due to their great application prospects in the photoelectronic field. However, the poor long-term stability still limits their practical use. In this work, a whole series of CsPbX3 QDs were precipitated in a germanate glass matrix by a melt quenching method. The emission wavelength can be tunable in the entire visible spectral region by adjusting of the halide ions and the thermal treatment process. The photoluminescence quantum yield of CsPbBrxI3-x QDs glass can reach up to 38.24%. The exciton binding energies of CsPbBrxCl3-x, CsPbBr3 and CsPbI3 QDs glass are about 67 meV, 160 meV and 290 meV, respectively. Additionally, the influence of the thermal treatment temperature on photoluminescence properties of CsPbBrxI3-x QDs glass was investigated in detail. These results will be of benefitting to their practical applications, such as display devices and WLEDs.

The effect of thermal treatment temperature on the crystal structure and electrochemical performance of the coconut shell-based hard carbon

The demand for energy has been increased, and the supply of lithium-ion batteries (LIBs) can not meet the demand for energy storage. Sodium-ion batteries (SIBs) have become ideal alternative products because of their low cost and the similar charge and discharge mechanism with LIBs. Meanwhile, the hard carbon anode materials have made tremendous progress, and the hard carbon materials which have the advantages of rich resources, low cost, and high-safety have been widely studied. Herein, carbonized coconut shell was used as raw material for the preparation of hard carbon, and the relationship between thermal treatment temperature and the crystal structure and electrochemical performance was investigated. It is found that the hard carbon prepared at 1300 °C has the best specific capacity. At the current density of 100 mA/g, it can reach 224.36 mAh/g after 100 cycles. The hard carbon material prepared at 1200 °C has the best rate performance, which can reach 54.5 mAh/g at the current density of 2 A/g.