Conventional methods for synthesizing zircon (ZrSiO4) are often associated with high energy consumption, lengthy processing times, and particle agglomeration challenges. In this study, we present a novel microwave-assisted spray solution combustion synthesis (MW-SSCS) technique to fabricate zircon nanocomposites containing vanadium, using NH4VO3 as the vanadium source. The combustion reaction kinetics of ZrO2-SiO2:0.5V were investigated by differential scanning calorimetry (DSC) and analyzed using the Kissinger-Akahira-Sunose (KAS) model, providing insight into the reaction mechanisms. The effects of key pyrolysis parameters-substrate temperature, precursor molarity, and flow rate-on phase purity and morphology were systematically examined. Elongated and spherical nanostructures formed at 700 degrees C within 18 min without any post-treatment, while high-purity hexagonal-close-packed (HCP) zircon particles sized 40-60 nm were obtained at 800 degrees C after 1 h of calcination. Compared to traditional synthesis routes requiring temperatures above 1500 degrees C and extended calcination periods, the MW-SSCS method significantly reduces energy consumption and processing time, while effectively minimizing particle agglomeration and the formation of smoky byproducts. This work offers a scalable and energy-efficient pathway for the synthesis of advanced ceramic pigments with tunable structural and morphological features.

Due to increasing environmental concerns and requirements, the adoption of modern heating methods is strongly recommended. The microwave-based system has attracted considerable attention due to its efficiency, low carbon footprint, low energy consumption, and short process timing. Our studies on microwave heating for synthesizing cobalt and various alloys showed a significant need for novel predictors to model microwave heating processes. This paper is novel in its evaluation of the performance of outstanding numerical methods for solving microwave-based reactions in both kinetic and environmental aspects. As a case study, the experimental results related to the reaction of cobalt metal oxide with syngas under microwave heating were compared to the orthogonal collocation outcomes, and outstanding results were reported with a mean error lower than 5%. The emissions from a microwave and an electrical furnace, based on kinetic values, were also compared. To evaluate numerical methods for different types of reactions in the mentioned microwave heating process, the governing equations from the modeling of gas-solid catalyzed reactions with different reaction orders were solved using the perturbation and orthogonal collocation methods. The environmental analysis demonstrated that the microwave process offered notable environmental and operational advantages over the furnace process, including significantly faster CO removal, more controllable CO₂ emissions, higher energy efficiency, and a reduced overall carbon footprint by possibly reducing energy consumption.

Applications of porous media are increasing in various scientific disciplines, such as energy storage or conversion systems and giant capacitors. It has been recognized that the transport and reaction processes occurring within pores significantly influence the performance of porous media, while transport phenomena at the pore scale are not well-characterized. The experimental effective diffusion coefficient of naphthalene-nitrogen was studied using a regression method based on a radial dimension transient model of diffusion in the porous medium. The weight of samples containing naphthalene was continuously recorded by a digital precision balance. This study was performed at three different temperatures: 303.15 K (30 °C), 323.15 K (50 °C), and 343.15 K (70 °C) at atmospheric pressure, with porous metal matrices of 90

In this paper, iron-doped ZrSiO4 nanoceramics were prepared via straightforward solution combustion synthesis (SCS) method using glycine as a fuel. Different amounts of iron ranging from 5 to 50 mol

The Zeolitic Imidazolate Frameworks (ZIFs), specifically ZIF-90, were synthesized and incorporated as fillers in the fabrication of composite membranes using sulfonated poly (1,4-phenylene ether-ether-sulfone) (SPEES). The inclusion of ZIF-90 in the polymeric matrix demonstrated an improved enhancement in proton transport compared to that observed for SPEES or standalone ZIFs. Subsequently, a mathematical model was developed to forecast proton conductivity under diverse temperature and water content conditions. The modeling exhibited remarkable concordance with the experimental findings. In the subsequent phase of this study, electrochemical impedance spectroscopy (EIS) was employed to assess the real and imaginary components of complex conductivity. The temperature and frequency dependence of the real part of the conductivity were scrutinized. Additionally, tan(δ) analysis was performed for membrane under scrutiny, and the resulting value was applied to ascertain the diffusion coefficient through the analysis of electrode polarization (EP). The findings indicated a diffusion coefficient of 2.41 × 10–5 cm2/s for the SPEES membrane, whereas for the SPEES/ZIF-90 membrane, the value stood at 2.01 × 10–4 cm2/s at 80 °C. These results suggest that ZIF-90 holds significant promise as a filler in composite membranes, contributing to the improvement of proton transport properties.

The escalating global temperatures and their adverse effects underscore the growing imperative for the widespread adoption of clean fuels, notably hydrogen. Proton Exchange Membrane Fuel Cells (PEMFC) emerge as a pivotal green energy technology, facilitating electricity and water generation. The optimization of PEMFC efficiency hinges on the judicious selection and fabrication of polymer membranes. Within innovative materials, Zeolitic Imidazolate Frameworks (ZIFs) represent a novel subclass within the expansive family of Metal-Organic Frameworks (MOFs). ZIFs exhibit promising potential in PEMFCs, owing to their distinctive properties such as a substantial contact surface, inherent porosity, and a sizable pore volume. This comprehensive review delves into composite membranes featuring ZIFs, shedding light on their chemical and thermal attributes. Additionally, the exploration extends to elucidating the diverse applications of ZIF compounds, accompanied by an in-depth discussion of selected chemical and thermal properties inherent to ZIF compounds. Incorporating ZIFs into various polymers yielded intriguing outcomes, demonstrating a notable enhancement in proton conductivity. The compilation of this review aims to provide researchers with foundational insights into the realm of ZIFs, serving as a valuable resource for future investigations and advancements in the field.

In the present paper, the recovery of mixed spent cathodes is evaluated and performed through a hydrogen reduction process. Firstly, the lithium is isolated by the hydrogen reduction process as LiOH at 600 ^∘ C for 15 min with 10 ^∘ C for 90 min with 50 ml/g. The filtration residual is reduced by using a carbothermic reduction process and a hydrogen reduction method. The first one is performed under an Ar atmosphere at 900 ^∘ C for 210 min and the second one is conducted at 800 ^∘ C for 150 min. The purer products are achieved using the hydrogen reduction method at lower temperatures and shorter holding times compared to a carbothermic reduction process with recovery percentages of 100

In the present study, Ni-Co, Ni-Cu bimetallic nanocatalyst (BMNC), and Ni-Co-Cu trimetallic nanocatalyst (TMNC) were synthesized on the gamma-Al2O3 base using the thermogravimetric method. The thermogravimetric method is a pyrometallurgical route (TGPR). These nanocatalysts were produced from the reduction reaction of binary and ternary mixture of NiO, Co3O4, and CuO metal oxide nanoparticles (NPs), along with a gamma-Al2O3 base with methane gas. The reduction reaction was carried out at 830 degrees C with 23vol.% of methane as a reducing agent under atmospheric pressure. The properties of NiCo/gamma-Al2O3 BMNC and NiCoCu/gamma-Al2O3 TMNC were analysed by XRD, FESEM, TPO, and BET and then their the nanocatalysts' performance was evaluated with dry reforming of methane (DRM). The XRD results indicated that in the production of NPs-C, the utilised metal oxides were converted into metal NPs, which created bi- and tri-metallic bonding with the gamma-Al2O3 base. BET analysis demonstrated that the surface area and pores volume of the TMNC reduced as the primary CuO particles entered the pores, due to the smaller average size of these particles in comparison to nickel and cobalt oxide NPs. In addition, the catalytic results revealed that NiCo/gamma-Al2O3 BMNC has the highest catalytic performance compared to NiCoCu/gamma-Al2O3 TMNC, due to the absence of CuO and the appropriate synergistic effect of nickel-cobalt in the DRM. The TPO analysis confirmed the decrease in the amount of carbon sediment in the TMNC, resulted from the presence of Cu.

The novelty of the present paper was the construction of a new reactor to synthesize the cobalt nanoparticles (NPs) by solution combustion synthesis (SCS) method for reducing the processing temperature of cobalt production. To perform the SCS process, a reactor was designed and constructed and the synthesis process was performed using cobalt (II) nitrate-6-water as oxidizer along with glycine and urea as fuels. The effect of the molar ratio of glycine fuel to oxidizer and fuel type parameters on the purity of the products were examined. The XRD and FESEM analysis were used to characterize the obtained products. Based on FESEM analysis and the Scherrer equation, the mean size of all samples was under 100 nm and the reactor loaded with the glycine fuel provided the lowest particle sizes by around 14 nm and produced particles with better surface adhesion. It was found that the glycine fuel was determined the best fuel compared to urea because of producing temperatures near 400°C. Compared to traditional gas-solid reactions, the operating temperature of this process was under 400°C which was considerably lower than the operating temperature of gas-solid reactions occurred at temperatures higher than 800°C.

Proton exchange membrane fuel cells (PEMFC) have received a lot of interest and use metal–organic frameworks (MOF)/polymer nanocomposite membranes. Zeolite imidazole framework-90 (ZIF-90) was employed as an addition in the sulfonated poly (1, 4-phenylene ether-ether-sulfone) (SPEES) matrix in order to investigate the proton conductivity in a novel nanocomposite membrane made of SPEES/ ZIF. The high porosity, free surface, and presence of the aldehyde group in the ZIF-90 nanostructure have a substantial impact on enhancing the mechanical, chemical, thermal, and proton conductivity capabilities of the SPEES/ZIF-90 nanocomposite membranes. The results indicate that the utilization of SPEES/ZIF-90 nanocomposite membranes with 3wt% ZIF-90 resulted in enhanced proton conductivity of up to 160 mS/cm at 90 °C and 98% relative humidity (RH). This is a significant improvement compared to the SPEES membrane which exhibited a proton conductivity of 55 mS/cm under the same conditions, indicating a 1.9-fold increase in performance. Furthermore, the SPEES/ZIF-90/3 membrane exhibited a remarkable 79% improvement in maximum power density, achieving a value of 0.52 W/cm 2 at 0.5 V and 98% RH, which is 79% higher than that of the pristine SPEES membrane.

Recycling end-of-life lithium-ion batteries (LIBs) as a problematic waste stream has become an urgent area of research worldwide. This paper details an efficient, simple, and environmentally friendly technique for metal recovery from a mixture of three types of spent LIBs cathodes. By using the carbothermal process, Li is first isolated in solid lithium carbonate with minimal emission, and to optimize Li isolation the effects of temperature, holding time, and graphite dosage are investigated. Under optimal carbothermal conditions of 700 degrees C, 60 min, and 15% graphite, phases of CoO, NiO, Li2CO3, and small amounts of Ni and Co are formed. This stage is followed by dissolution in cold water where 94.6% of Li is recovered under optimal leaching conditions. After filtration, the residual component is reduced by the second carbothermal reduction under vacuum at 900 degrees C for 120 min, resulting in the formation of high purity metals.

The aims of this paper were to reduce the operating temperature of SiO2-stabilized zirconia synthesis compared to previous works and produce a practical ZrSiO4 ceramic by the solution combustion method. The analysis of DSC, XRD, FTIR, FE-SEM, TEM, SAED, HR-TEM and Rietveld refinement were used to characterize the resulting products. The results demonstrated that the type and amount of fuels (i.e., urea and glycine) were important factors in self-sustained reaction and crystalline structures of zirconia. A comparison was also done to study the impact of the calcination temperature on the phase evolution of stabilized monoclinic zirconia, obtained 96.67% of m-ZrO2 with crystallite size of 31 nm. Finally, sintering process of m-ZrO2 was applied to synthesize ZrSiO4. The crystallization of ZrSiO4 from the binary system of m-ZrO2 and SiO2 has been the subject of extensive study, commonly obtained with cations at high temperatures. Interestingly, the present study achieved ZrSiO4 without the presence of cation at low temperature, and indicated 79.51% purity with compressive strength and Vickers hardness of 416.38 ± 6.79 MPa and 1143.2 ± 40.2 HV (11.21 ± 0.39 GPa), respectively. Due to appropriate appearance color and excellent mechanical properties of ZrSiO4 synthesized at low-temperature processing, this approach can be promising for the biomedical application.

Glycerol as an indirect reducing agent was used for the reduction of Iron oxide/Cobalt oxide (FeOx/CoO1-x) compounds. The effect of FeO amount on the morphology and conversion rate of obtained alloys was investigated. In addition, the system was modeled to investigate the increasing trend of the bed temperature along with samples, which were in the form of semispherical granules. The samples and products were characterized by XRD, TEM, EDX-MAP, and FESEM, analysis. The results proved that more amount of FeO in the sample led to higher conversion rate due to thermodynamic reasons. It was found that the gaseous products from pyrolysis reaction of 7 cc glycerol at 850 degrees C reduced (FeO)(0.8)/(CoO)(0.2) granule to Fe/Co alloy with a conversation rate equal to around 92%. Moreover, the system was modeled to evaluate the increasing trend of the bed temperature. The predicted temperature increasing trend of the sample and the bed had a good agreement with experimental data. In the suggested reactor, two processes of pyrolysis and reduction reactions were done, simultaneously, and the process of producing alloys was very short (6 min at 850 degrees C). The suggested system was very safe because the bed received all the electromagnetic waves and converted them to heat. This system can be highly considered by the alloy industry.

In this work, a novel two-step fixed bed reactor is designed and constructed for the synthesis of cobalt performed by the reduction of cobalt oxide under microwave heating. In the first step, glycerol is sprayed using a spray device on a bed of activated carbon placed in the bottom of reactor to perform the pyrolysis reaction of glycerol. In the second step, the syngas produced from the pyrolysis reaction is immediately used for performing the reduction reaction of cobalt oxide granules embedded in the bed of activated carbon. The raw material and the obtained products are characterized by FESEM, EDS, and XRD analysis. The effect of temperature and the amount of sprayed glycerol on morphology and conversion rate of products are investigated. The analysis of XRD and EDS proved the formation of 91.75% Co using 7 cc of glycerol at the initial temperature of 900 degrees C after 4 min.

A demonstration was represented to exhibit the crystallization of ZrSiO4 from ZrO2 -SiO2 binary composite using additive of NH4VO3 via solution combustion synthesis (SCS) technique. The XRD and Rietveld results revealed favorable crystallization of zircon with crystallite size about 50 nm. FE-SEM images showed the particles with uniform hexagonal-close-packed morphology. Furthermore, the effect of vanadium on self-sustained reaction was studied by Kissinger-Akahira-Sunose method and DSC data. The results indicated that the presence of vanadium decreased flame temperature and activation energy. The activation energies in combustion reaction for ZrO2 SiO2 and ZrSiO4 were found to be 189.401 kJ/mol and 66.032 kJ/mol, respectively.

The Samaria-promoted of 10wt% Nickel-CMK-3 and 10wt% Nickel-SBA-15 were synthesized by the Samarium (3wt %) addition, and using the two-solvent impregnation technique. The N2 adsorption-desorption, field emission scanning electron microscopy, energy dispersive x-ray analysis, x-ray diffraction and the transmission electron microscopy analysis were used to characterize of the Samaria modified and unmodified catalysts. Furthermore, the catalyst performances were tested under the carbon dioxide reforming of methane. As a result, the x-ray diffraction and surface area investigation revealed that the addition of Samaria (Sm2O3) into the Nickel (Ni) catalysts/silica (SBA-15) and carbon (CMK-3) mesostructures decreased the particles size and surface area according to the TEM micrographs; however, mproved the catalysts activity and catalysts stability. The role of investigation of support in the dry reforming reaction indicated that the activity and catalysts stability of the Ni/CMK-3 catalysts were lower than the Ni/SBA-15 catalysts due to the agglomeration of Ni nanoparticles on the CMK-3 support, the sintering of Ni nanoparticles, the burning of the mesoporous carbon support in the higher temperatures and the blocking of Ni nanoparticles into the deposited carbon nanotubes (CNTs).

The high-temperature porous nanocomposite membranes based on polybenzimidazole and lignin with incorporation of TiO2 nanoparticles with high acid retaining ability were prepared and used in fuel cell. The effect of adding TiO2 nanoparticles was investigated on micro structure and physical properties of PBI membrane. The TiO2 nanoparticles prevent of open-surface micro-pores formation and the evaporation of phosphoric acid at high temperature from PBI matrix. The number of open voids within the nanocomposite membranes was reduced by increasing the content of TiO2 nanoparticles in membrane. Therefore, the proton conductivity of the nanocomposite membranes enhanced due to increasing of acid storage ability at the high temperatures. At temperature of 160 degrees C, the proton conductivity of the nanocomposite membrane obtained 176 mS/cm. The power density of 0.58 W/cm(2) was achieved for PBI-lignin-TiO2 nanocomposite membranes (lignin/PBI: 20 and 5.5 wt.% of TiO2) at 0.5 V and 180 degrees C under dry condition, which confirmed that these developed membranes have high performance.

Currently, most automotive industries use fossil fuels, like diesel fuel, which are harmful for the environment and are known as the main reason for global warming. To reduce the adverse effects of these fuels, scholars have investigated and suggested green fuels like biodiesel. However, further studies should be conducted to improve the functionality of biodiesel fuel in diesel engines. In the current study, three completely distinct biodiesel fuels (namely, B1 with 96 % lauric oil, B2 with 88 % oleic oil, and B3 with 89.5 % ricinoleic oil) were numerically evaluated to carefully investigate the effects of the number of carbon atoms, the OH bond, and viscosity on the performance of a CI engine. First, the predicted in-cylinder pressure, the rate of heat released, and NO emissions were compared to experimental results and an appropriate accord was obtained. For the mentioned biodiesels, the parameters of engine speed, injection angle, piston bowl center depth, and compression ratio were investigated by CFD code under different engine speeds. It was found that changing the piston bowl center depth (PBCD) value from 0.0042 to 0.009 m increased NO and the indicated power by 4% and 3%, respectively, for B1, B2, and B3 biofuels. In addition, when the engine was fueled by Corylus avellana biodiesel, the change in compression ratio from 16 to 24 increased peak pressure and torque by around 77 % and 17 %, respectively. The results showed that the cylinder fueled by high viscosity biodiesel has lower air-fuel mixing. A fuel that has more oxygen atoms in its chemical structure can produce higher NO emissions. Moreover, the injection angle of 150° led to increased fuel consumption rate and indicated power compared to the injection angle of 160°. It was determined that the compression ratio has significant effects on emission and combustion characteristics.

In this study, we performed a computational fluid dynamics (CFD) modeling of tetracycline photocatalytic degradation using rGO/ZnO/Cu as the photocatalyst. The photoreactor was an unbaffled dished bottom tank with a backswept impeller and four lamp tubes. The CFD equations were solved for light intensity, velocity, pressure, and concentration fields in time-dependent modes of the fluid regime. Our model was more complex than the previous studies in several ways: we modeled the system is 3D instead of 2D, allowed variation of light intensity and pressure throughout the photoreactor, and traced the change of key parameters over time during the initiation phase until the steady state was reached. The flow pattern was solved and visualized in the presence of mixer in vertical and horizontal cuts. Experimentally measured concentrations over time matched model predictions well but also indicated the need for yet more complex models incorporating more factors that affect reaction rates.

Tetracycline (TC) photodegradation using rGO/ZnO/Cu nano-powder was investigated under visible irradiation. The effect of operating conditions such as pH, photocatalyst concentration, and initial concentration of pollutant on reaction rate constant and total organic carbon (TOC) removal was studied. Complete removal of 40mg/L tetracycline concentrations was achieved at pH 8 and 1 g/L rGO/ZnO/Cu. The best model fitted to the experimental data was pseudo-second-order, with maximum and minimum kinetic rate constants of TC elimination estimated at 1 g/L (0.007280 L/min/mg) and photolysis (0.000018 L/min/mg), respectively. The TC and TOC removal percentages reached 100% and 91.2% after 180 and 300 min, respectively.