Microwave Combustion Research Articles

A photo-triggered bioactive nanohydrogel loaded with niobium carbide for stem cell osteogenic differentiation

Photo-Cross-Linkable hydrogel has attracted immense interest in the regeneration of bone repair and regeneration strategies due to its superior biocompatibility and tunable mechanical properties. Recently, Nb was reported to strongly promote the bone regeneration process via an accelerated osteoblast-modulated alkaline phosphatase activity mechanism. In particular, Nb2C MXenes have drawn widespread attention due to their excellent biocompatibility and ability to induce bone formation. However, the easy agglomeration of Nb2C nanosheets and subsequent low cell endocytosis efficacy greatly suppressed the osteogenesis effect. In this study, a subtractive nanopore-engineered Nb2C MXene was prepared through a microwave combustion method, gelatin methacrylate was used as the carrier hydrogel, and the photo-triggered Porous-Nb2C@GelMA hydrogel was fabricated by a photo-triggered process. The pore-forming strategy not only successfully improved the distribution of Nb2C and formed more homogenous Porous-Nb2C@GelMA hydrogels but also guided bone marrow mesenchymal stem cells (BMSCs) toward osteoblast differentiation. Porous Nb2C provided convenient cellular grasping and endocytosis for BMSCs, which further created a favorable environment for differentiation and osteogenesis. This, in turn, leads to an increase in the expression of osteogenic markers, such as ALP and ARS, as well as osteogenic factors, such as BMP-2, COL-1, OCN, and OPN. Consequently, enhancing the regenerative microenvironment by incorporating porous Nb2C composite hydrogels shows promise for application in bone regeneration.

A smartphone-assisted ultrasensitive colorimetric aptasensor based on DNA-encoded porous MXene nanozyme for visual detection of okadaic acid

The smartphone-assisted ultrasensitive colorimetric aptasensor based on DNA-encoded porous Ti3C2 nanozyme (Apt-P-Ti3C2) was exploited for real-time detection of OA. Porous Ti3C2 (P-Ti3C2) MXene with outstanding peroxidase-like activities were crafted using microwave combustion, facilitating the efficient catalysis of chromogenic substrate oxidation by H2O2. The integration of a considerable number of unsaturated Ti center edges and residual Mn2+ within the single-layer porous Ti3C2 framework augmented the adsorption capacity of DNA aptamer, thereby yielding a heightened catalytic efficacy of P-Ti3C2 nanoparticles. The enhanced catalytic activity of P-Ti3C2 can be partially diminished through specific recognition of OA. Concurrently, a smartphone platform was integrated for signal reading based on the colorimetric sensing strategy. The smartphone-based biosensor exhibited a reliable and ultrasensitive capability for OA detection with the detection limit of 0.38 ng·mL−1. It is anticipated that the developed smartphone-based biosensing platform can provide a prospective ultrasensitive detection method for marine algal toxin in food analysis.

Single Step Synthesis of Cu2ZnSnS4 by Microwave Combustion Method

We report a novel single step process to synthesize Cu2ZnSnS4 nanopowder. Our novel approach is based on combustion method assisted with microwave irradiation. The obtained results showed that the precursors can be quickly decomposed in the microwave field to form Cu2ZnSnS4 nanopowder. The effects of fuel and microwave power on structures and properties of the nanopowder were investigated thoroughly by Raman spectroscopy. This synthesis process is promising for large scale fabrication of light absorbing materials for photovoltaic devices because it is facile, low cost, non-vacuum, single step and time saving.

CaAl1.5Fe0.5O4/6%Ni-ZnO nanocomposites: Synthesis, characterization and effective photocatalyst for the photocatalytic degradation of methylene blue dye

This study focuses on synthesizing and analyzing properties of calcium aluminate photocatalytic nanoparticles using the microwave (MW) combustion method by following the rules of green chemistry and investigates their effectiveness in the adsorption of methylene blue (MB) dye which is a crucial contaminant that enters water resources. The synthesized nanoparticles, including CaAl2O4 (CAO), CaAl1.5Fe0.5O4 (CAFO), 6 %Ni-ZnO (NZO), and CaAl1.5Fe0.5O4/6%Ni-ZnO (CAFONZO) composites, were characterized using various techniques. XRD analysis confirmed the formation of spinel structures in all samples. The crystallite size and lattice constants were determined, showing a reduction in Crystallite size of CAO from 45.98 nm to 37.55 nm after Fe3 + doping. Then, with the formation of CAFONZO Crystallite size 13.99 nm was obtained. FT-IR analysis revealed the chemical interactions between atoms in the spinel structures Nitrogen adsorption/desorption isotherms were used to determine the specific surface area of nanoparticles, pore volume, and pore size. Specific surface area of CAO, CAFO, and CAFONZO are 1.637, 1.745, and 9.903 (m2/g), respectively. SEM and TEM images provided insight into the morphology and size of the nanoparticles. According to TEM images, after Fe3 + doping, the size of particles decreased from 85 to 32 nm. UV-DRS was performed to determine the optical band gap energy of the photocatalysts. The calculated band gap values of pure CAO, CAFO, and NZO nanoparticles were 3.2 eV, 2.5 eV, and 2.7 eV, respectively. Mott-Schottky analysis indicated the type of semiconductors and the energy levels of the conduction and valence bands. Valence band (VB) values of CAFO and NZO are 2.86 eV and 2.03 eV, respectively. The photocatalytic activity of the nanoparticles was evaluated by degrading MB under visible light illumination. The adsorption studies were conducted by varying the dosage, pollutant concentration, and pH. The results showed that CAFONZO nanoparticles exhibited the highest photocatalytic efficiency, achieving 96 % degradation of MB within 120 min. The combined photocatalyst demonstrated improved efficiency compared to the individual components.

Determination of Major Heavy Metal Levels in Pepper Gas Used as Chemical Agents in CBRN Field

Introduction: The pepper gases used in the study are in the group of riot control agents. In this study; It was aimed to determine the main heavy metal levels of pepper gases obtained from capsaicin, the active ingredient of peppers grown in soil that we think may contain heavy metals. Material and Method: The presence of a total of 7 heavy metals, including iron, chromium, cobalt, copper, cadmium, lead and nickel, was investigated. The pepper gas sprays were subjected to sample preparation with a microwave combustion device. Then, heavy metal analyzes of the prepared samples were carried out with the ICP OES device. Results: According to this; As a result of the measurements, Chromium (Cr), Nickel (Ni), Cadmium (Cd) and Cobalt (Co) elements were not found in any of the samples. The amount of Lead (Pb) was determined as 0.653±0.064 mg/kg, and the amount of Iron (Fe) was 5.246±0.000 mg/kg. Finally, the Copper (Cu) element detected in a single sample was measured as 0.815 mg/kg. Discussion and Conclusion: We also think that the necessary sensitivity should be shown in laboratory and clinical studies to examine the content of pepper spray and to determine the optimum ratios of its active ingredients. We foresee that preparing promotional brochures, informative public service ads on topics such as what pepper gas is in what situations pepper gas should be used, and informing the public about the health problems it may cause will increase the conscious use of pepper gas.

Response surface methodology based investigations of total organic carbon removal using cerium oxide nanoparticle

This study aimed to optimize the removal of total organic carbon (TOC) from drinking water using cerium oxide nanoparticle (CONP) through response surface methodology (RSM) based approach. The CONP was synthesized using an efficient microwave combustion (EMC) technique. It was further characterised by High-resolution transmission electron microscopy (HR-TEM), X-Ray diffraction (XRD), energy dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET) surface area analysis, and zeta potential. CONP was found highly efficient in removing up to 94 % TOC at the optimum condition i.e., pH = 7, dosage = 0.5 g/L, and contact time = 30 min. Pareto analysis revealed that amongst all the selected variables, the CONP dose had the greatest cumulative impact on TOC removal. The second-order polynomial model developed using the RSM technique was found highly accurate in predicting the removal of TOC from drinking water (R2 = 0.98). The study offers a unique approach for reducing the number of experimental trials and arriving at an optimal experimental conditions to achieve higher TOC adsorption efficiency.

Study of microstructure and corrosion behavior of nano-Al2O3 coating layers on TiO2 substrate via polymeric method and microwave combustion

The study describes the successful development of a TiO2 ceramic substrate with a protective nano-Al2O3 coating using two different coating techniques: microwave combustion and polymeric methods. The coated ceramics demonstrate enhanced corrosion resistance compared to the uncoated substrate. The optimal TiO2 substrate was prepared by firing it at 1000 °C. This was done to give the desired physical properties of the TiO2 substrate for the coating procedures. Nano-Al2O3 powder was coated onto the surface of the TiO2 substrates. The TiO2 substrates with the Al2O3 coating were then calcined (heat-treated) at 800 and 1000 °C. The structures, morphology, phase composition, apparent porosity, bulk density, and compressive strength of the substrate and coated substrate were characterized. Upon firing at 1000 °C, it was discovered that the two phases of TiO2—rutile and anatase—combine in the substrate. Once the substrate has been coated with nano Al2O3 at 1000 °C, the anatase is transferred into rutile. When compared to the substrate, the coated substrate resulted in a decrease in porosity and an increase in strength. The efficiency of the ceramic metal nanoparticles Al2O3 as a good coating material to protect the TiO2 substrates against the effect of the corrosive medium 0.5 M solution of H2SO4 was measured by two methods: potentio-dynamic polarization (PDP) and the electrochemical impedance spectroscopy (EIS). The results indicated that the corrosion rate was decreased after the substrate coated with alumina from (67.71 to 16.30 C.R. mm/year) and the percentage of the inhibition efficiency recorded a high value reaching (78.56%). The surface morphology and composition after electrochemical measurements are investigated using SEM and EDX analysis. After conducting the corrosion tests and all the characterization, the results indicated that the coated TiO2 substrate prepared by the polymeric method at 800 °C displayed the best physical, mechanical, and corrosion-resistant behavior.

Synthesis, characterization and corrosive resistance of ZnO and ZrO2 coated TiO2 substrate prepared via polymeric method and microwave combustion

The TiO2 substrate coatings containing varied ZnO or ZrO2 nanoparticles were made using the polymeric and microwave combustion methods and then thermally treated at various temperatures. Furthermore, before coating on the substrate, the produced nanoparticles undergo characterization and calcination to optimize the conditions for developing ZnO and ZrO2 phases and track their composition. The X-ray diffraction method (XRD), transmission electron microscopy (TEM), and infrared analysis (IR) are used to characterize the calcined produced nanoparticles. After heat treatment at 1000 °C, the TiO2 substrate is prepared. The produced coated substrate is studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (IR), apparent porosity, bulk density, chemical corrosive properties and electrochemical measurement in 3.5 % NaCl and 1 M HCl solutions. The corrosion resistance of ZnO or ZrO2-covered TiO2 substrate is ascertained by anticorrosive behaviors, which include weight loss, apparent porosity, corrosion rate, and SEM. The findings showed that 800 °C is the ideal temperature for preparing ZrO2-coated substrate, whereas 1000 °C is the perfect temperature for preparing ZnO-coated substrate. The microstructure reveals surface micro-cracks on the ZrO2-coated TiO2 substrate. Good dispersion, homogeneity, and compaction were noted for the ZnO-coated substrate. Between 14 and 17 % of the ZnO-coated substrate and 20–21 % of the ZrO2-coated substrate, made via polymeric and microwave combustion techniques, had visible porosity when ZnO-coated samples exhibited greater corrosion resistance against NaCl media. In contrast, ZrO2-coated samples had much stronger anticorrosive qualities in HCl media than uncoated and Zn-coated samples. According to the electrochemical results, the ZnO-coated TiO2 synthesized by polymeric technique at 1000 °C showed 99.86 % inhibitory efficiency against NaCl. An inhibitory efficiency of 94.4 % was observed in a ZrO2-coated TiO2 substrate that was produced at 800 °C using a polymeric technique.

Comparative study of the composition and microstructural properties of semi-coke from microwave and conventional pyrolysis of low rank coal

Microwave pyrolysis technology can effectively realize the clean and quality improvement of coal. In order to study the changes of each component of coal in the process of microwave pyrolysis, the d002, La, Lc, combustion reactivity and conductivity of semi-coke after pyrolysis were analyzed by using XRD, TG, conductivity meter and other testing instruments, and the infrared spectra of semi-coke after pyrolysis were finely resolved by using Origin peak-splitting technique, and the composition of the coal gas in the process of pyrolysis and its percentage content were analyzed. The composition and percentage content of gas in the pyrolysis process were analyzed and compared with conventional pyrolysis. The results showed that compared with conventional pyrolysis, microwave pyrolysis can be completed at a lower temperature and microwave pyrolysis is more favorable to the release of volatile components, in which the content of CO and H2 in the gas fraction increased significantly compared with conventional pyrolysis. At the same pyrolysis temperature, the microwave semi-coke has a higher maximum combustion rate temperature than the conventional semi-coke, which is conducive to improving the thermal stability of semi-coke. The orderliness of the semi-coke increased with the increase of pyrolysis final temperature, resulting in the phenomenon of "similar graphitization". The increase in the number of carbon microcrystalline structures generates off-domain electrons, leading to a significant increase in conductivity. Meanwhile, FT-IR peak fitting analysis revealed that the R value inflection point temperature of microwave semi-coke was much lower than that of conventional semi-coke, which further proved that microwave pyrolysis could be accomplished at lower temperatures, and the C value showed a decreasing tendency with the increase of the final temperature of pyrolysis, which indicated that pyrolysis was an effective method to improve the quality of coal. The above analysis shows that compared with conventional pyrolysis, microwave can prepare high stability and high conductivity semi-coke at lower temperature.

Design of zinc-doped copper ferrite nanostructures using microwave combustion process and its supercapacitive features

Design of zinc-doped copper ferrite nanostructures using microwave combustion process and its supercapacitive features

Influence of Bi3+ ions on structural, morphology, elemental, vibrational, optical, magnetic, NLO and optical limiting properties of lanthanum ferrites nanoparticles

Nanoparticles of LaFe1-xBixO3 were successfully synthesized through the microwave combustion process (MCP) employing l-alanine as the fuel source. XRD and FT-IR analyses conclusively confirmed the orthorhombic structure of lanthanum ferrite, with the mean crystallite size varying between 56.32 and 25.43 nm. The optical energy gap value, calculated from UV–vis spectra, fell within the range of 1.84 to 2.49 eV. EDX analyses verified the presence of Bi, La, Fe, and O elements. Furthermore, FE-SEM images exhibited the nanoparticles' distinctive aggregated spherical morphology. Notably, VSM analysis showcased the robust diamagnetic behavior of LaFe1-xBixO3 nanoparticles. In photoluminescence's spectra, the samples underwent excitation with a wavelength of 315 nm. The values of Hc (coercivity) and Mr (remanence) fell within the range of 121.98 to 332.39 Oe and 0.1592 to 0.0907 emu/g for LaFe1-xBixO3 respectively. Z-scan experiments yielded values for the nonlinear susceptibility, index of nonlinear refraction, and coefficient of nonlinear absorption. The findings from optical limiting studies serve as additional verification, underscoring the suitability of these materials as promising options for integration into devices, including optical switches and optical power limiters.

Unveiling the role of rare earth dopant in metal molybdate nanocomposites via facile microwave-combustion strategy and their effect on antibacterial activity

Abstract Developing a robust material holding antimicrobial assets has been an efficient strategy for reducing the risk of infections related to healthcare, significantly with medical devices and touch surfaces. Molybdenum-based compounds have drawn momentous attraction because of their unique characteristics. A series of undoped and 5 % rare earth (Ce & La) doped metal (Ni, Co & Bi) molybdate nanocomposites have been prepared by facile microwave combustion method and characterized. The present study investigates the effect of dopants on crystal structure and morphology, and their impact on anti-bacterial properties is noticed. The UV–Vis. absorption spectra of all samples show a broad absorption band between 280 and 430 nm. The antibacterial properties of the prepared nanocomposites have been examined by the agar diffusion method against three Gram-positive and two Gram-negative bacteria, showing good bactericidal efficiency for all samples, except 5 % Ce–NiMoO4 (antibacterial activity exclusively against Gram-positive bacteria) and 5 % La–NiMoO4 (no antibacterial activity) nanocomposites. This work provided a novel pathway in the biomaterial field.

Low-temperature cluster spin glass transition in the single-domain NiCr2O4 nanoparticles

NiCr2O4 nanoparticles with average particle size ∼15 nm, a single-domain size maintains the bulk canted antiferromagnetic ground state, were synthesized by a microwave combustion method. The magnetic behavior was carefully investigated by static and dynamic magnetic susceptibility measurements. In addition to a spin-glass-like behavior below paramagnetic-ferrimagnetic transition at T C, the NiCr2O4 nanoparticles demonstrate a low-temperature cluster spin glass transition below the spin canting transition T S, which manifests itself as a magnetic anomaly peak around ∼12 K (at 100 Oe) in the zero-field cooled magnetization with a relatively stronger field dependence in a ‘de Almeida-Thouless’ line for spin glasses. The AC susceptibility analyses in different approaches demonstrate a larger relative peak temperature variation per frequency decade and a longer characteristic relaxation time in the order of 0.04 and 10−7 s, against 0.01 and 10−9 s for the high-temperature blocking, indicating the slow spin dynamics for the low-temperature cluster glassy phase. A field-temperature magnetic phase diagram is proposed for the single-domain NiCr2O4 nanoparticles.

Magnetically separable Cu-Fe nanophotocatalyst with enhanced photocatalytic performance under visible-light irradiation: Optimizing the fuel type and heating approach in the synthesis process

This study aimed to examine the influence of fuel type and heating technique on the solution one-step solution combustion synthesis of CuFe2O4 spinel-type photocatalysts. The primary goal was to establish the best configuration of nanophotocatalysts with desirable characteristics, leading to improved photodegradation of dye pollutants when exposed to simulated solar radiation. Cu-spinel nanophotocatalysts were generated using a one-step combustion method involving three distinct fuels (urea, glycine, and citric acid) and two heating strategies (microwave and muffle furnace). The synthesized nanophotocatalysts were characterized through a range of tests, including XRD, FESEM, EDX, BET-BJH, FTIR, VSM, PL, DRS, and pHpzc analyses. During the simulated irradiation of sunlight, the efficacy of the Cu-spinel photocatalyst was evaluated using high-concentration Congo red, a widely used textile dye. Test results indicate that the Cu-spinel nanophotocatalyst formed utilizing glycine and microwave combustion displayed a desirable photocatalytic activity by degradation of 97 % of Congo red in 100 min. In addition, the photocatalytic efficiency of Congo red degradation was significantly enhanced compared to the other fuels and the conventional heating approach. Furthermore, CuFe(G-MW) demonstrated high stability throughout four cycles. Finally, a proposed mechanism for the degradation of Congo red using a CuFe(G-MW) nanophotocatalyst was presented.

Synthesis of transition metal oxide-based nanocomposite as a robust electrode with a simple approach for supercabattery application

With the advancement of technology, there has been a growing demand for high-capacity energy storing devices possessing good durability and cost-effective production. Herein, Ce doped cobalt molybdate (CoMoO4) nanocomposites by microwave combustion is prepared and their structural, morphological, spectroscopical and electrochemical behavior are investigated. The β phase monoclinic structure have been confirmed by XRD analysis. The electrochemical behavior of 5% Ce-CoMoO4 sample shows a specific capacitance value eight times higher than of its undoped CoMoO4 sample. Furthermore, a symmetric 5% Ce-CoMoO4 device displays an energy density of 105.54 Wh kg−1 at 1.7 mA cm−2 current density with 82.06% retention after 5000 continuous charge-discharge cycles. The outcome of the present investigation offers the doping approach enhances the energy-storing ability of cobalt molybdate and become an exceptionally promising candidate in the area of energy storage today.

Investigations on structural, dielectric, and third-order nonlinear optical studies of Ni0.5Zn0.5Fe2O4 nanoparticles by microwave combustion method with different fuels (glycine, urea and citric acid)

In this article, Ni0.5Zn0.5Fe2O4 nanoparticles (NPs) were synthesized via microwave-assisted combustion method. XRD investigation indicates the cubic spinel structure. At ambient temperature, the dielectric constant and loss were determined by modulating the applied frequency (50 Hz to 200 kHz). The calculated third-order NLO susceptibility (χ(3)) was found for glycine (2.385 × 10-6esu), urea (0.9696 × 10-6esu) and citric acid (2.755 × 10-6esu). However, this work reveals that synthesized NPs have high convenience for optoelectronic, optical switching, and limiting applications.

(Digital Presentation) Green Synthesis of Calcium Ferrite Particles and Preliminary Study of Their Application for Electrochemical Detection

This work presents results of the synthesis of mixed metal oxides such as calcium ferrite by dissolving Ca(NO3)2.4H2O, Fe(NO3)3.9H2O and NH4OH with constant stirring, and assisted with conventional heating or microwave (MAE) combustion. using natural aloe vera extract as fuel at 900°C for 3 hours. The resulting material was characterized by instrumental methods for powders. Calcium ferrite powders were used for the modification of the surface of a glassy carbon electrode. The modified electrodes were used for the electrochemical investigation of acetaminophen (ACe) and acyclovir (ACy), at controlled pH. The preliminary results demonstrated the potential application of calcium ferrite powders in the electrochemical detection of molecules of pharmaceutical interest.

Synergistic Effects of Pyrrolic N/Pyridinic N on Ultrafast Microwave Synthesized Porous CoP/Ni2P to Boost Electrocatalytic Hydrogen Generation.

Transition metal phosphides are ideal inexpensive electrocatalysts for water-splitting, but the catalytic activity still falls behind that of noble metal catalysts. Therefore, developing valid strategies to boost the electrocatalytic activity is urgent to promote large-scale applications. Herein, a microwave combustion strategy (20 s) is applied to synthesize N-doped CoP/Ni2P heterojunctions (N-CoP/Ni2P) with porous structure. The porous structure expands the specific surface area and accelerates the mass transport efficiency. Importantly, the pyrrolic N/pyridinic N content is adjusted by changing the amount of urea during the synthesis process and then optimizing the adsorption/desorption capacity for H*/OH* to enhance the catalyst activity. Then, the synthesized N-CoP/Ni2P exhibits small overpotentials of 111 and 133 mV for HER in acidic and alkaline electrolytes and 290 mV for OER in alkaline electrolytes. This work provides an original and efficient approach to the synthesis of porous metal phosphides.

Structural, Characterization, And Morphological Properties Of Copper Nanoparticles From Opuntia Ficus Indica Plant

AbstractOne of the most recent areas of interest in current nanotechnologies and nanosciences is the use of biomaterials in the manufacturing of nanoparticles. More and more research is being carried out on environmentally friendly methods to create metal oxide nanoparticles (NP), with the intention of preventing any potential risks associated with harmful substances for a safe and healthy environment. In this study, Copper Oxide (CuO) is synthesized utilizing Opuntia ficus‐indica as the plant extract using a Microwave Combustion Technique (MCM) and its comparison against the Conventional Combustion Method (CCM) are investigated. The synthesized CuO nanoparticles were characterized using X‐ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT‐IR), Scanning Electron Microscopy (SEM), and Energy Dispersive X‐ray Analysis (EDX) analysis. Photoluminescence spectroscopy was undertaken to acquire emission and absorption spectra and determine defects in the structures of all synthesized nanopowder samples. The antibacterial activity of the CuO nanoparticles was evaluated in‐vitro using gram‐negative and gram‐positive bacteria (Bacillus subtilis, Staphylococcus aureus). Enhanced anti‐bactericidal activity was shown against Gram‐negative bacteria compared to Gram‐positive bacteria. Through these findings, the use of CuO using Opuntia ficus indica extracts is hereby shown to be a cost‐effective and environmentally friendly alternative and that can be used in a variety of applications.

Microwave Combustion Synthesis of La1-xGdxFeO3 (x = 0 to 0.25) Nanoparticles: Structural, Magnetic, Vibrational, Morphology and Optical Behavior

Microwave Combustion Synthesis of La1-xGdxFeO3 (x = 0 to 0.25) Nanoparticles: Structural, Magnetic, Vibrational, Morphology and Optical Behavior