Effect Of Thermal Treatment Temperature Research Articles

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.

Simultaneous Removal of Heavy Metals (Cu, Cd, Cr, Ni, Zn and Pb) from Aqueous Solutions Using Thermally Treated Romanian Zeolitic Volcanic Tuff.

Increased concentrations of heavy metals in the environment are of public health concern, their removal from waters receiving considerable interest. The aim of this paper was to study the simultaneous adsorption of heavy metals (Cu, Cd, Cr, Ni, Zn and Pb) from aqueous solutions using the zeolitic volcanic tuffs as adsorbents. The effect of thermal treatment temperature, particle size and initial metal concentrations on the metal ions sorption was investigated. The selectivity of used zeolite for the adsorption of studied heavy metals followed the order: Pb > Cr > Cu > Zn > Cd > Ni. The removal efficiency of the heavy metals was strongly influenced by the particle sizes, the samples with smaller particle size (0–0.05 mm) being more efficient in heavy metals removal than those with larger particle size (1–3 mm). Generally, no relevant changes were observed in heavy metals removal efficiency for the treatment temperatures of 200 °C and 350 °C. Moreover, at a higher temperature (550 °C), a decrease in the removal efficiencies was observed. The Cd, Zn, Cu, Cr, Zn and Ni sorption was best described by Langmuir model according to the high values of correlation coefficient. The pseudo-first-order kinetic model presented the best correlation of the experimental data.

Effect of different thermal treatment temperatures on dimensional stability and mechanical properties of M50 steel

By using field-emission scanning electron microscopy, X-ray diffraction, impact and tensile-property tests, the effect of thermal treatment temperatures in stabilization treatment on the microstructure, dimensional stability and mechanical properties of M50 bearing steel was studied. Results show that the size of M50 steel decreases due to carbide precipitation at 400 °C, 420 °C, 440 °C and 480 °C, and increases due to martensite transformation at 460 °C. In the thermal treatment temperature range of 400–480 °C, the amount of secondary carbide precipitation in M50 steel increases first and then decreases with the increase of thermal treatment temperature, and the amount of carbide precipitation in the steel reaches the maximum at 460 °C. During the thermal treatment temperature range of 400–460 °C, the residual austenite gradually decomposes and decreases in quantity. However, at 480 °C, the residual austenite has relatively higher carbon content to make it more stable and less likely to decompose. At the same time, the tensile properties are slightly improved, the impact toughness decreases at 460 °C and improved under other conditions.

Effect of thermal treatment temperature on catalytic performance of Pt/TiO2 nanobelt composite for HCHO oxidation

TiO2 nanobelts were prepared by hydrothermal synthesis and acid treatment, then calcination at different temperatures. And subsequently Pt nanoparticles were deposited on the TiO2 nanobelts. Pt/TiO2 catalytic properties were investigated in the oxidation of formaldehyde. These catalysts were characterized by various techniques and the characterization results showed that the applied thermal treatment temperature greatly influenced the phase composition and surface structure of TiO2 nanobelts, as well as the number of oxygen vacancies and hydroxyl groups on the surface. The Pt/TiO2 nanobelts thermally treated at 600°C had more oxygen vacancies, which were conducive to the activation of adsorbed oxygen, formed more Ti-(OH)x-Pt species, and showed higher catalytic activity. At 25°C and relative humidity of 55%, the conversion of formaldehyde reached 91.6%.

Enhanced ferroelectric properties of P(VDF-TrFE) thin film on single-layer graphene simply adjusted by crystallization condition

Ferroelectric polymer/graphene hybrid systems have received considerable attention due to their promising utilization in flexible electronics. The crystallization of ferroelectric polymers such as poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) can obviously affect the electronic properties of the hybrid systems. Here, the effects of thermal treatment temperature and crystallization temperature on the structure, morphology, and piezoelectric/ferroelectric properties of P(VDF-TrFE) on graphene substrate are reported. Moreover, the dependence of coercive voltage and piezoelectric coefficient (d33) on thermal treatment temperature or crystallization temperature is explored. It is identified that coercive voltage is only relying on the crystallization temperature other than thermal treatment temperature. Once crystallization temperature changes, both coercive voltage and d33 alter significantly and an optimum crystallization temperature exists at which the sample shows the best properties. The relationship between structure and piezoelectric/ferroelectric properties is built. These findings provide useful guidance for fabricating piezoelectric/ferroelectric P(VDF-TrFE)/graphene devices with high performance.

Effect of low thermal treatment temperatures on the morphological, optical and electrical properties of Sn1-xMnxTe nanocomposite films incorporated with indium cations

Amorphous chalcogenide semiconductors have advantageous optical and electrochemical properties, but the influence of the thermal treatment temperature on these properties is not clearly understood. In this study, In3+-incorporated Sn1-xMnxTe nanocomposite films were prepared on commercial glass substrates using a solution-based doctor-blading method and low thermal treatment temperatures. The effect of the thermal treatment temperature (50–200 °C) on the optical and electrical properties of the nanocomposite films was investigated. X-ray diffraction results confirmed that an amorphous nanocomposite film was formed at each thermal treatment temperature. However, variation in the optical parameters and electrical performance of the nanocomposite films with the thermal treatment temperature indicated that this temperature should not exceed 150 °C. Optimization of the thermal treatment temperature improved the light-harvesting ability of the nanocomposite films and enhanced the polarization of the incident radiation. These phenomena were caused by an increase in atomic oscillations associated with higher dipole moments in the films. The nanocomposite films subjected to thermal treatment at temperatures below 150 °C also exhibited the highest electrical conductivity. These results will allow the synthesis of improved materials for applications in solar selective surfaces and electro-optical, photovoltaic-thermal, and sensor devices.

Glycerol Esterification over Sn(II)-Exchanged Keggin Heteropoly Salt Catalysts: Effect of Thermal Treatment Temperature

In this work, Sn(II)-exchanged Keggin heteropoly acid salts were evaluated as solid catalysts in glycerol esterification reactions with acetic acid. All the Sn(II) heteropoly salts and their precur...

Thermal crosslinking and fabrication of poly (N-isopropylacrylamide) nanofibers

To prepare thermo-responsive nanofibers with excellent stability and high sensitivity, the copolymer P (NIPAm-co-NMA) is synthesized by free radical copolymerization of N-isopropylacrylamide (NIPAm) and N-methylol acrylamide (NMA). Furthermore, the polymer is crosslinked via thermal treatment which results in highly cross-linked copolymer, thereby increasing the resistance to dissolution around lower critical solution temperature (LCST). In addition, the copolymer is electrospun into nanofibers. The influence of electrospinning condition on the morphology and diameter of the resulting nanofibers, and the effects of thermal treatment temperature and duration on the degree of cross-linking and morphology retaining ability are systematically investigated. The results show that the optimal spinning conditions are as follows: the polymer concentration is 10% and the spinning voltage is 10 kV. The optimal thermal cross-linking temperature is 130 ℃ and the treatment duration is 6 h. The degree of cross-linking of the as-obtained fibers is 82%. The fibers after thermal cross-linking could maintain the stability in water at a low temperature. After 5 cycles of heating-cooling, the fibers could retain 98% of the initial weights.

ZnS-containing industrial waste: Antibacterial activity and effects of thermal treatment temperature and atmosphere on photocatalytic activity

ZnS-containing industrial waste (ZnSW) from the mining-metallurgy industry was characterized as a useful photocatalytic material for environmental remediation. The XRD results reveal that the ZnSW contains cubic ZnS (sphalerite) as a major phase and hexagonal ZnS (wurtzite), triclinic FeS2 (pyrite) and hexagonal SiO2 (quartz) as minor phases. The antibacterial activity of the ZnSW was tested for four bacterial strains. The antibacterial activity against L. innocua under UV light irradiation is comparable to that observed with MRSA, whereas the inactivation rate against E. coli reaches 99% within 2 h of UV light irradiation. The ZnSW is found to be less effective in the inactivation of S. enteretidis. The impact of thermal treatment temperature (400–1000 °C) and atmosphere (in air and NH3) on photocatalytic activity of the ZnSW for photodegradation of gaseous acetaldehyde (AcH) and Bisphenol A (BPA) in aqueous solution under simulated solar light were investigated. The sample thermally treated at 500 °C in air completely mineralized AcH and BPA within 4 and 2 h of the photocatalytic reaction, respectively, due to the formation of a ZnSZnO heterojunction that promoted an effective charge separation. The sample thermally treated at 1000 °C in NH3 exhibited the highest photocatalytic efficiency in complete photodegradation of AcH and BPA within 3.5 and 1.5 h of the photocatalytic reaction, respectively, because of the introduction of nitrogen and formation of midgap defect states. The present study demonstrates the importance of the thermal treatment temperature and atmosphere for improving the photocatalytic activity of ZnS-containing industrial waste for environmental remediation.

Real‐Time Dilation Observation of Si‐Alloy Electrode Using Thermally Treated Poly (Amide‐Imide) as a Binder for Lithium Ion Battery

Real time dilation behaviors of a Si‐Ti‐Fe‐Al alloy electrode adopting a poly (amide‐imide) binder were investigated to understand the effects of thermal treatment temperature for PAI binder on the electrochemical performance of the Si‐alloy electrode using an in‐situ electrochemical dilatometer. In situ measurement of the electrode thickness showed that the changes in the volume of the Si electrode was suppressed by heat treatment greater than 300 °C, which well agreed with the improved cycle performance of the Si‐alloy electrode thermally treated at the same temperature. Differential dilation plots of the Si‐alloy electrodes were found to reveal more detailed changes in the volume of the Si‐alloy electrode, thus showing that the enhanced mechanical strength of thermally treated PAI effectively could control the expansion and contraction of the Si‐alloy electrode and ensuring a more stable cycle performance of the Si‐alloy electrode.

Thermal conductivity of thermally damaged Beishan granite under uniaxial compression

Investigations of the thermal conductivity of thermally damaged Beishan granite under uniaxial compression were conducted. Rectangular prism specimens preconditioned at 105 °C were heated at different temperatures (400, 550 and 650 °C) and then cooled to room temperature (27 °C) for testing. Using the transient plane source (TPS) method, in combination with a servo-controlled compression machine and an acoustic emission (AE) monitoring system, lateral thermal conductivities, stress–strain relations and AE responses of the thermally treated specimens during uniaxial compression were measured. The effects of thermal treatment temperature on the strength, deformation and AE parameters were analyzed. The lateral thermal conductivity evolution characteristics for the specimens in the deformation process were studied. The stress-and-deformation-dependent lateral thermal conductivities were also evaluated. The experimental results indicate that the lateral thermal conductivity varies nonlinearly with increasing axial stress due to closure, initiation and propagation of microcracks within the specimens. Moreover, significant differences exist in the lateral thermal conductivity behaviors between the specimens subjected to different temperature treatments. Furthermore, to reveal the influence of cracking behaviors on the thermal conductivity of the thermally damaged specimens in compression, numerical modeling was performed using PFC and the simulation results agree well with the experimental data.

Effect of Thermal Treatment Temperature on the Flowability and Wax Deposition Characteristics of Changqing Waxy Crude Oil

The influence of thermal treatment temperature on the flowability and wax deposition characteristics of Changqing waxy crude oil was researched in detail through pour point/rheological tests, a cylindrical Couette wax deposition experimental device, DSC analyses, asphaltenes stability tests, and microscopic observations. It is found that the flowability of the crude oil can be greatly improved through increasing the thermal treatment temperature. Meanwhile, the wax deposition rate of the crude oil can be outstandingly inhibited with the increase of thermal treatment temperature from 50 to 70 °C. Moreover, the flow regime can also influence the wax deposition characteristics. Under cold flow regime (22 °C/12 °C), the structure of formed wax deposits is homogeneous while the aging of the wax deposits is not obvious. Under hot flow regime (30 °C/20 °C), the aging of the wax deposits is obvious, but a heterogeneous two-layer structure exists in the formed wax deposits at the thermal treatment temperatures 50 ...

Thermal, structural, textural and optical properties of ZnO/ZnAl2O4 mixed metal oxide-based Zn/Al layered double hydroxide

Mixed metal oxides (MMO) with a homogenously distributed ZnAl2O4 in ZnO network were prepared through a novel combination of co-precipitation and thermal treatment approaches using Zn/Al-layered double hydroxide (LDH) as precursor. The effect of thermal treatment temperature of Zn/Al-LDH for the formation of ZnO/ZnAl2O4-MMO was studied via their thermal, structural, textural and optical properties. The results reveal that the synthesized Zn/Al-LDH was advanced to ZnO/ZnAl2O4-MMO starting at 200 °C, while heat treatment at 400 °C resulted in the optimum BET surface area of 53 m2 g−1 with formation of mesoporous structure. Furthermore, diffuse reflectance microscopy showed that there is more than one energy band gap of pristine Zn/Al-LDH, while samples treated at 200 °C and above demonstrated a single energy band gap with redshift from 3.3 to 3.21 eV. Photoluminescence (PL) analysis showed a quench in the PL spectra as the temperature increased to 400 °C, where the sample with the optimum surface area presents the highest INBE/IDLE ratio of 0.78. A precise control of the thermal treatment temperature provides short pathways for preparing high BET surface area MMO-based materials.

The Effect of Thermal Treatment Temperature and Duration on Electrochemistry Performance of LiNi1/3Co1/3Mn1/3O2 Cathode Materials for Lithium-ion Batteries

Background: LiNi1/3Mn1/3Co1/3O2 derived from the solid-state method suffers from the problem of significant irreversible charge-discharge behavior. To improve the electrochemical performance of LiNi1/3Mn1/3Co1/3O2, there are several important factors, such as starting raw materials, precursor, preparation method and conditions. In this work, the layered LiNi1/3Mn1/3 Co1/3O2 material was prepared by solid-state reaction. By varying the temperature and duration of synthesis thermal treatment, the greater crystallinity and well-ordered layered LiNi1/3Mn1/3Co1/3O2 cathode material has been successfully synthesized. The structural properties, morphology and electrochemical properties of LiNi1/3Mn1/3Co1/3O2 powders have been investigated in detail. Methods: LiNi1/3Co1/3Mn1/3O2 cathode material was synthesized via a high-temperature solid-state method. Stoichiometric amounts of Ni(CH3COO)2•4H2O, Co(CH3COO)2•4H2O, Mn(CH3COO)2• 4H2O, and Li2CO3 as raw materials were homogenized mixed in a ball mill for 8 h at 240 rpm. By varying the temperature and duration of synthesis thermal treatment, LiNi1/3Co1/3Mn1/3O2 cathode materials with different electrochemistry performance were achieved. (a) The effect of the temperature of synthesis thermal treatment on electrochemistry performance of LiNi1/3Co1/3Mn1/3O2 was explored by calcining the above mixed powder at 800°C, 850°C, 900°C, 950°C, and 1000°C for 12 h in air at a rate of 5°C min-1. Then the target product was prepared at last. The obtained compound was named as N-800, N-850, N-900, N-950 and N-1000, respectively. (b) In order to explore the effect of the duration of synthesis thermal treatment on electrochemistry performance of LiNi1/3 Co1/3Mn1/3O2 cathode material, the above mixed raw materials were calcined at 900°C for 4 h, 8 h, 12 h, 16 h and 20 h in air at a rate of 5°C min-1. The obtained compound was named as N-4, N-8, N- 12, N-16 and N-20, respectively. The N-900 and N-12 are the same sample. Results: The cathode material sintered at 900°C for 12 h revealed the best electrochemical performance, with high-capacity and recyclability compared with other materials. Its initial discharge capacity attains 182.4 mAh g-1 at 0.2 C in the voltage range of 2.5-4.6 V, which can be attributed to its greater crystallinity and well-ordered layered structure. Compared with other studies on lithium-ion batteries given in literature, this work provides a sample, optimal and mild synthetic conditions to synthesize the cathode materials with great electrochemistry performance. Conclusion: A greater crystallinity and well-ordered layered LiNi1/3Mn1/3Co1/3O2 powders had been successfully synthesized by mixing raw materials under various temperatures and duration of synthesis thermal treatment. The XRD results indicated the I(003)/I(104) values of N-900 (N-12) is 1.591 larger than 1.2, which illustrates no undesirable cation mixing to be occurred. In this work, from the results of electrochemical property experiments, it can be indicated that the optimal synthesized conditions are 900°C for 12 h. When the calcination temperature is too low and the calcined time is too short, the material is poorly crystalline and has a poor layer structure. When the calcination temperature is too high and the calcined time is too long, lithium salt is evaporated completely during the calcination process resulting in a poor electrochemistry performance.

Effects of thermal treatment on the properties of defatted soya bean flour and its adhesion to plywood.

With an attempt to economically and efficiently improve the water resistance of defatted soya bean flour (DSF)-based wood adhesives, DSF was subjected to thermal treatment at various temperatures (65°C, 80°C, 95°C, 110°C and 125°C) for 30 min. The effects of thermal treatment temperature onto the chemical structure, crystalline degree, water-insoluble content and acetaldehyde value of the thermally treated DSF (T-DSF) were investigated. The thermal stabilities and bonding properties of soya bean adhesives prepared from T-DSF and cross-linker epichlorohydrin-modified polyamide (EMPA) were also investigated. Test results indicated that both the water-insoluble content and the acetaldehyde value of T-DSF increased after thermal treatment, reaching the highest values of 27.28% and 26.81 mg g−1, respectively. All plywood bonded with the T-DSF-based adhesive withstood a 28 h boiling–dry–boiling accelerated ageing treatment, while plywood bonded with the DSF-based adhesive delaminated after 4 h of water boiling, demonstrating the significantly improved water resistance of the T-DSF-based adhesives. Related analyses also confirmed that this improvement was due to: (i) the formation of insoluble cross-linked structures of T-DSF resulting from protein–protein self-cross-linking reactions and the protein–carbohydrate Maillard reaction and (ii) increased cross-linking efficiency between T-DSF and cross-linker EMPA owing to more T-DSF-reactive groups being released after thermal treatment.

Effect of Thermal Treatment Temperature on Stacking Structure and Carbon Aromaticity in Coal

Effect of Thermal Treatment Temperature on Stacking Structure and Carbon Aromaticity in Coal

A prospective study on thermally-cyclodehydrated poly(imide-oxadiazole) membranes for pervaporation dehydration

In this work, we study the preparation and pervaporation application of thermally cyclodehydrated poly(imide-oxadiazole) (PIO) membranes. The poly(imide-hydrazide) (PIH) precursor is firstly fabricated by the crosslinking of polyimide by 1,3,5-benzenetricarboxylic acid trihydrazide (BTCH). Then a thermal treatment is applied to induce the cyclodehydration of PIH into PIO. The effects of thermal treatment temperature on membrane properties and the pervaporation performance for isopropanol dehydration are investigated and characterized by various techniques. The results show that the thermal treatment has two opposite effects, i.e., thermal annealing and thermal cyclodehydration, which are both enhanced with the increase in the thermal treatment temperature. When a low thermal treatment temperature is applied (200–275°C), the thermal cyclodehydration plays the leading role, resulting in the impressive increase of the flux with reasonable separation factor. While for PIO membrane treated with a relative high thermal treatment temperature (> 300°C), the physical annealing may play the dominant role and leads to an opposite effect. Thus, with a suitable thermal treatment temperature (300°C in this study), an optimized separation performance of the cyclodehydrated PIO membrane could be achieved. In addition, the effect of the operation temperature on the membrane performance and the long-term stability are also studied. The obtained promising performance indicates a great potential of the developed PIO membranes for pervaporation or other membrane-based separation applications.

Quasi-Spherical Brookite TiO2 Nanostructures Synthesized Using Solvothermal Method in the Presence of Oxalic Acid

Brookite TiO2, the latest TiO2 photocatalyst, promises to be an interesting candidate for photocatalytic applications because of its unique physical and chemical properties. In this study, pure-phase brookite TiO2 with a quasi-spherical nanostructure was successfully synthesized via a solvothermal method using tetrabutyl titanate (Ti(OC4H9)4, TBOT) as the Ti source in the presence of oxalic acid. NaOH was used to regulate the pH of solution. The structure and morphology of the samples were then analyzed using multiple methods, such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) measurements and ultraviolet–visible diffuse spectroscopy (UV–Vis). Photocatalytic activities of the as-synthesized brookite TiO2 were evaluated by degrading aqueous methylene blue solution under UV light irradiation. The effect of thermal treatment temperature on photocatalytic activity of the samples was also investigated. The produced brookite TiO2 nanopowders calcined at 500 °C for 2 h showed the highest photocatalytic activity, and the corresponding degradation rate of methylene blue (10 mg/L) reached 96.7% after 90 min of illumination. In addition, the formation mechanism of pure-phase brookite TiO2 was investigated. It was found that the formation of pure-phase brookite TiO2 in this study was ascribed to the combined action of oxalic acid and sodium hydroxide.

Carbon nanofibers prepared by electrospinning accompanied with phase-separation method for supercapacitors: Effect of thermal treatment temperature

Abstract

Measuring the Modulus of Elasticity of Thermally Treated Spruce Wood using the Ultrasound and Resonance Methods

The effect of thermal treatment temperatures on the dynamic and static modulus of elasticity (MOE) of Norway spruce wood (Picea abies (L.) H. Karst.) was evaluated. The dynamic MOE was measured using ultrasound and resonance methods in the longitudinal and transverse directions. The static MOE was determined by the three-point bending test. The dynamic MOE values determined by the ultrasound method were higher than the static MOE values in each case. As the temperature of the thermal treatment increased, the difference between the dynamic and static MOE values decreased. The MOE increased with increasing temperature, and it was more pronounced on a tangential surface. Increasing the sensor distance had a positive effect on the correlation between the static and dynamic MOE, and the effect from the increased temperature decreased. Measurement by the resonance method showed twice as high MOE values in the transverse direction than in the longitudinal direction. The thermal treatment caused a significant decrease in the MOE only in the transverse direction, and the differences were insignificant in the longitudinal direction. The dynamic MOE values measured by the resonance method were higher than the static MOE values but slightly lower than the values measured by the ultrasound method.