Ultrasonic-assisted Preparation Research Articles

Ultrasonic-assisted preparation of zinc oxide for bacteria inhibition: influence of dispersants and antibacterial mechanism

Ultrasonic-assisted preparation of zinc oxide for bacteria inhibition: influence of dispersants and antibacterial mechanism

Ultrasound-assisted preparation of crumb rubber modified asphalt: Characterization and molecular dynamics simulation

The traditional method of crumb rubber modified asphalt (CRMA) preparation can improve the stability but is not conducive to cleaner production. From the perspective of process optimization, ultrasound is introduced into the crumb rubber modified asphalt preparation process, and the high temperature, high pressure and high energy accompanied by the cavitation effect are used to generate free radical triggering chemical effects at the two-phase interface between crumb rubber and asphalt. In this paper, the influence of ultrasound on the compatibility and stability of crumb rubber modified asphalt system was evaluated by combining experiment and molecular dynamics simulation. An experimental platform for ultrasound-assisted preparation of crumb rubber modified asphalt was established. The effects of ultrasonic on the physical properties of asphalt and crumb rubber modified asphalt were studied through Brookfield viscosity test, thin film oven aging test and Fourier infrared spectroscopy. The base, aged, and ultrasonically treated asphalt samples were simulated using molecular dynamics, and various parameters such as Cohesive Energy Density (CED), Mean Square Displacement (MSD), and Free Volume Fraction (FFV) of asphalt and its components were calculated and analyzed. The results showed that under the ultrasonic-assisted preparation, the agglomeration phenomenon of rubber particles is weakened, the particle size is reduced, the penetration degree is reduced, and the compatibility between rubber and asphalt is improved. Under the action of ultrasonic, the MSD and diffusion coefficient of crumb rubber modified asphalt are much higher than other kinds of asphalt, the dipole moment is increased, and the molecular motion range is wider. This indicates that the diffusion ability of crumb rubber modified asphalt is significantly enhanced under the external force of ultrasonic simulation. The molecular bonds of crumb rubber modified asphalt changes greatly, the energy decreases obviously, and the system stability increases. In conclusion, ultrasonic action on crumb rubber modified asphalt preparation is a green and effective way to improve system stability and compatibility.

Ultrasonic-Assisted Preparation of Biodiesel Products from Vegetable Oils.

Utilizing vegetable oil as a sustainable feedstock, this study presents an innovative approach to ultrasonic-assisted transesterification for biodiesel synthesis. This alkaline-catalyzed procedure harnesses ultrasound as a potent energy input, facilitating the rapid conversion of extra virgin olive oil into biodiesel. In this demonstration, the reaction is run in an ultrasonic bath under ambient conditions for 15 min, requiring a 1:6 molar ratio of extra virgin olive oil to methanol and a minimum amount of KOH as the catalyst. The physiochemical properties of biodiesel are also reported. Emphasizing the remarkable advantages of ultrasonic-assisted transesterification, this method demonstrates notable reductions in reaction and separation times, achieving near-perfect purity (~100%), high yields, and negligible waste generation. Importantly, these benefits are achieved within a framework that prioritizes safety and environmental sustainability. These compelling findings underscore the effectiveness of this approach in converting vegetable oil into biodiesel, positioning it as a viable option for both research and practical applications.

Ultrasound-Assisted Preparation and Performance Regulation of Electrocatalytic Materials.

With the advancement of scientific research, the introduction of external physical methods not only adds extra freedom to the design of electro-catalytical processes for green technologies but also effectively improves the reactivity of materials. Physical methods can adjust the intrinsic activity of materials and modulate the local environment at the solid-liquid interface. In particular, this approach holds great promise in the field of electrocatalysis. Among them, the ultrasonic waves have shown reasonable control over the preparation of materials and the electrocatalytic process. However, the research on coupling ultrasonic waves and electrocatalysis is still early. The understanding of their mechanisms needs to be more comprehensive and deep enough. Firstly, this article extensively discusses the adhibition of the ultrasonic-assisted preparation of metal-based catalysts and their catalytic performance as electrocatalysts. The obtained metal-based catalysts exhibit improved electrocatalytic performances due to their high surface area and more exposed active sites. Additionally, this article also points out some urgent unresolved issues in the synthesis of materials using ultrasonic waves and the regulation of electrocatalytic performance. Lastly, the challenges and opportunities in this field are discussed, providing new insights for improving the catalytic performance of transition metal-based electrocatalysts.

Ultrasonic-assisted preparation of organic amine-modified SBA-15 for CO2 capture in wide temperature range: Experimental and computational investigation

Amine-modified mesoporous silicon was widely used for CO2 capture. However, its adsorption capability was significantly affected by temperature and humidity. In this paper, tetraethylenepentamine (TEPA) modified SBA-15 adsorbents were prepared for capturing CO2. The effects of the modification method, the concentration of TEPA, the adsorption temperature, and the humidity of atmosphere on CO2 adsorption capability were studied. Moreover, combined with molecular dynamics (MD) and density functional theory (DFT) computations, the diffusion characteristics and adsorption mechanism were explored. The CO2 adsorption capability of the adsorbent prepared by the ultrasonic impregnation method was higher than those prepared by the stirring impregnation method, owing to that ultrasonic impregnation could promote the uniformity of TEPA. With the increase of TEPA concentration of SBA-15, the CO2 adsorption capability increased. SBA-15-2 had the highest CO2 adsorption capability of 1.17 mmol/g at 30 °C. This was due to the N-containing functional groups, showing good affinity for CO2, introduced by TEPA impregnation. When the temperature increased from 30 °C to 70 °C, the CO2 adsorption capability of all modified SBA-15 adsorbents decreased, since the CO2 adsorption was an exothermic reaction. SBA-15-2 showed better water vapor resistance than SBA-15-2 (Stir). This was related to the higher dispersity of organic carbon chain introduced by TEPA modification after ultrasonic impregnation. The organic carbon chain of SBA-15-2 increased the water vapor resistance by reducing the hydroxyl group. Finally, from a microscopic aspect, the MD simulation suggested that impregnated TEPA inside SBA-15 may improve CO2 capture by increasing the thickness of effective adsorption layer. Besides, the DFT simulation showed that TEPA modification increased the adsorption energy of SBA-15 on CO2. This serves as a reference for later mesoporous silicon adsorbent research and development on CO2 capture.

Research on structural strengthening technology for regenerative denitration catalysts.

The cost of replacing failed selective catalytic reduction (SCR) catalysts and their disposal as hazardous solid waste is high. If failed catalysts are recovered and regenerated into new SCR denitration catalysts, the cost of flue gas denitration can be effectively reduced. However, regenerated SCR catalysts have relatively low structural strength and activity and cannot yet form an effective replacement. In this study, aluminum dihydrogen phosphate, aluminum nitrate, and aluminum sulfate were used as structural strengthening agents in the regeneration of SCR catalysts, and over-impregnation, drumming-assisted impregnation, and ultrasonic-assisted preparation techniques were compared. The corresponding regenerated SCR catalysts were then prepared and analyzed for compressive strength, wear strength, H2-TPR, NH3-TPD, and in situ IR. Factors influencing the structural strength, physical properties, and catalytic activity of the regenerated catalysts were investigated. The best results were obtained as follows: compressive strength of 4.57 MPa, wear rate of 0.088% kg-1, and denitration of 58% after 10 min of drumming-assisted impregnation in an aluminum sulfate solution with a concentration of 16%. Based on this, a synergistic method for catalyst activity and structural strengthening was explored to support the design of better SCR catalysts for regeneration.

Ultrasonic-assisted preparation of interlaced layered hydrotalcite (U–Fe/Al-LDH) for high-efficiency removal of Cr(VI): Enhancing adsorption-coupled reduction capacity and stability

Cr(VI) contamination in aquatic systems has been a challenge for environmental science researchers. To environmental-friendly, stable, and efficiently remove Cr (VI), a novel layered double hydroxide was prepared through the ultrasonic-assisted co-precipitation method. The ultrasonic-assisted step prevented the Fe2+ oxidation, improved the morphology and performance, and finally, the adsorption-coupled reduction capacity and stability were enhanced. By adding U–Fe/Al-LDH (1.0 g/L) for Cr(VI) (100 mg/L), the removal rate reached 82.24%. The removal data were well fitted by the pseudo-second-order kinetic and Langmuir isotherm model. Using U–Fe/Al-LDH can be performed over a wide pH range (2–10), with a theoretical maximum removal capacity of 118.65 mg/g. The Cr(VI) with high toxicity was adsorbed and reduced to low-toxicity Cr(III). In the final phase, stable Cr(III) complex precipitates were generated. After 30 days, the dynamic leaching amounts of total Cr in used U–Fe/Al-LDH-2 were 0.1052 mg/L. Combined with the results of the influence experiment of coexisting anions and oxidants and the SO42− release experiment, the stability of the removal effect and the safety of U–Fe/Al-LDH were proved. In conclusion, U–Fe/Al-LDH-2 is a promising remediation agent and a feasible Cr(VI) removal method for the practical remediation.

Ultrasonic-assisted preparation of ultrafine Pd nanocatalysts loaded on Cl−-intercalated MgAl layered double hydroxides for the catalytic dehydrogenation of dodecahydro-N-ethylcarbazole

N-ethylcarbazole/dodecahydro-N-ethylcarbazole (NEC/H12-NEC) is a promising LOHC, and the development of a catalyst with high activity and stability is the key to realizing its reversible hydrogen storage process. In this paper, ultrafine Pd nanocrystalline catalysts (Pd/LDHs-us) supported on Cl--intercalated MgAl LDHs were prepared by a simple ultrasonic-assisted reduction method and applied in the dehydrogenation of 12H-NEC. In the process of ultrasonic-assisted reduction, the instantaneous high temperature generated by cavitation decomposed part of the CO32– in LDHs interlayer, and promoted PdCl42- to enter the interlayer and become new intercalated ions. At the same time, hydroxyl groups on the surface of LDHs were excited to generate hydrogen radicals (•H) with strong reducibility, which reduced PdCl42- to Pd nanoparticles (PdNPs) in situ. The remaining Cl- ions continued to exist in the interlayer as intercalated ions. The agglomeration of PdNPs was effectively inhibited, and the average particle size was 1.8 nm, which was uniformly dispersed on LDHs, which improved the catalytic activity of Pd/LDHs-us. The coordination between PdNPs and oxygen in the hydroxyl groups on the surface of LDHs improved its catalytic stability. Using Pd/LDHs-us catalyst, the conversion rate of H12-NEC was 100.0 %, and the dehydrogenation efficiency was 99.3 % at 180℃. When the reaction temperature drops to 170℃, the dehydrogenation efficiency can still reach 94.6 %, showing excellent catalytic performance. The study of dehydrogenation kinetics shows that the apparent activation energy of Pd/LDHs-us catalyst is only 90.97 kJ/mol. This provides a new method and idea for the preparation of efficient dehydrogenation catalysts in the future.

Ultrasonic-Assisted Preparation of WO3/SiO2 from Rigid Silicon Spheres for the Thiolation of Dimethyl Sulfide to Methanethiol

Ultrasonic-Assisted Preparation of WO3/SiO2 from Rigid Silicon Spheres for the Thiolation of Dimethyl Sulfide to Methanethiol

Ultrasonication-Assisted Preparation of a Composite of Neodymium Oxide-Carbon Nanoballs@Nanotubes for the Construction of a Voltammetric Platform Based on Boron Doped Diamond Electrodes for the Sensitive Determination of Caffeic Acid in Locally Grown Grapes

Ultrasonication-Assisted Preparation of a Composite of Neodymium Oxide-Carbon Nanoballs@Nanotubes for the Construction of a Voltammetric Platform Based on Boron Doped Diamond Electrodes for the Sensitive Determination of Caffeic Acid in Locally Grown Grapes

Ultrasonic-assisted preparation of eucalyptus oil nanoemulsion: Process optimization, in vitro digestive stability, and anti-Escherichia coli activity

Eucalyptus oil (EO) is a natural and effective antimicrobial agent; however, it has disadvantages such as poor water solubility and instability. The aim of this study was to investigate the effect of process vessels and preparation process parameters on the particle size of the emulsion droplets using ultrasonic technique and response surface methodology to prepare eucalyptus oil nanoemulsion (EONE). The optimal sonication process parameters in conical centrifuge tubes were confirmed: sonication distance of 0.9 cm, sonication amplitude of 18%, and sonication time of 2 min. Under these conditions, the particle size of EONE was 18.96 ± 4.66 nm, the polydispersity index was 0.39 ± 0.09, and the zeta potential was −31.17 ± 2.15 mV. In addition, the changes in particle size, potential, micromorphology, and anti-Escherichia coli activity of EONE during digestion were investigated by in vitro simulated digestion. The emulsion was stable in simulated salivary fluid, tended to aggregate in simulated gastric fluid, and increased in particle size and potential value in simulated intestinal fluid. EONE showed higher anti-E. coli activity than EO by simulated digestion. These results provide a useful reference for the in vivo antimicrobial application of the essential oil.

Ultrasonic-assisted preparation of α-Tocopherol/casein nanoparticles and application in grape seed oil emulsion

In this work casein (CN) was used as a carrier system for the hydrophobic agent α-tocopherol (α-TOC), and an amphiphilic self-assembling micellar nanostructure was formed with ultrasound treatment. The interaction mechanism was detected with UV–Vis spectroscopy, fluorescence spectroscopy, proton spectra, and Fourier transform infrared spectroscopy (FTIR). The stability of the nanoparticles was investigated by using typical processing and storage conditions (thermal, photo, 20 ± 2 °C and 4 ± 2 °C). Oil-in-water emulsions containing the self-assembled nanoparticles and grape seed oil were prepared, and the effect of emulsion oxidation stability was studied using the accelerated Rancimat method. The results indicated that the UV–Vis spectra of α-TOC/CN nanoparticles complexes were different for ultrasonic treatments performed with different combinations of power (100, 200, 300 W) and time (5, 10, and 15 min). The results of UV–Vis fluorescence spectrum data indicated that the secondary structure of casein changed in the presence of α-TOC. The nanoparticles exhibited the chemical shifts of conjugated double bonds. Interactions between α-TOC and casein at different molar concentrations resulted in a quenching of the intrinsic fluorescence at 280 nm and 295 nm. Moreover, by performing FTIR deconvolution analysis and multicomponent peak modeling, the relative quantitative amounts of α-helix and β-sheet protein secondary structures were determined. The self-assembled nanoparticles can improve the stability of α-TOC by protecting them against degradation caused by light and oxygen. The antioxidant activity of the nanoparticles was stronger than those of the two free samples. Lipid hydroperoxides remained at a low level throughout the course of the study in emulsions containing 200 mg α-TOC/kg oil with the nanoparticles. The presence of 100 and 200 mg α-TOC/kg oil led to a 78.54 and 63.54 μmol/L inhibition of TBARS formation with the nanoparticles, respectively, vs the free samples containing control after 180 mins.

Acenaphthene adsorption onto ultrasonic assisted fatty acid mediated porous activated carbon-characterization, isotherm and kinetic studies

Adsorbents originated from biological materials play a vital role in the remediation of diverse toxic pollutants due to their high efficacy, low cost and being environmentally friendly. The present study focusses on the palm shell activated carbon obtained from agricultural waste precursor (palm shell) with the aid of oleic acid activation along with ultrasonic assistance and its effective utilization for acenaphthene adsorption from aqueous and real effluent. The synthesized Ultrasonic assisted palm shell activated carbon (UAC) possessed high surface area of 506.84 m2/g and distinct porous structure as depicted by SEM analysis. The outcomes of zero discharge analyses and acenaphthene adsorption results vouchsafed that, using oleic acid as an effective catalyst, is explicitly advantageous to combine with ultrasonic assistance to fabricate a highly efficient adsorbent for acenaphthene removal from aqueous solution. The UAC obtained at the selected parameters levels, such as temperature of 45 °C and ultrasonic time of 40 min, has the adsorption capacity of 52.745 mg/g. Sips isotherm model computed from the experimental data gave the best fit among the examined isotherm models. To complete the study of adsorption properties of UAC towards acenaphthene, kinetic modeling and thermodynamic aspects of the adsorption process were also scrutinized. The kinetic studies proved that pseudo-second order model is compatible with the experimental data and thermodynamic results revealed that the adsorption process is of endothermic nature. Overall, ultrasonic-assisted preparation of activated carbon from palm shell actuated using Oleic acid was found to be a highly efficient adsorbent which was suitable for acenaphthene removal from aqueous solution.

Ultrasonic-assisted preparation of halloysite nanotubes/zirconia/carbon black nanocomposite for the highly sensitive determination of methyl parathion

Herein, a cost-effective and scalable ultrasound assisted approach was proposed to prepare the nanocomposite of halloysite nanotubes/zirconia/carbon black (Hal/ZrO2/CB), which was used to fabricate a novel electrochemical sensor for the highly sensitive determination of methyl parathion (MP). In the Hal/ZrO2/CB nanocomposite, Hal with large specific surface area and numerous active sites could enhance the adsorption capacity and accelerate the redox reaction of MP; ZrO2 nanoparticles with high affinity toward the phosphate group could contribute to good recognition performance for MP; CB nanoparticles with good dispersibility formed an interconnected pearl-chain-like conductive network. Benefitting from the synergistic effect of the three components, the Hal/ZrO2/CB/GCE (glassy carbon electrode) sensor showed a remarkably low detection limit of 5.23 nM in a good linear MP detection range of 0.01–10 μM. The Hal/ZrO2/CB/GCE sensor possessed a pretty decent practicality with satisfactory RSD and recovery results for the determination of MP in peach, pear, and apple juices. Therefore, the Hal/ZrO2/CB/GCE sensor has important implication on the quite sensitive detection of MP.

Ultrasonic-Assisted Preparation of α-Tocopherol/Casein Nanoparticles and Application in Grape Seed Oil Emulsion

In this work casein (CN) was used as a carrier system for hydrophobic agent α-tocopherol (α-TOC), an amphiphilic self-assembling micellar nanostructure was formed with ultrasound-assistance. The interaction mechanism was detected by UV-Vis spectroscopy, Fluorescence spectroscopy and Fourier transform infrared spectroscopy (FTIR), the stability of the nanoparticles was investigated by the typical processing and storage conditions. Oil-in-water emulsion containing self-assembled nanoparticles was prepared with grape seed oil, the effect of emulsion oxidation stability was studied with the professional rancimat. Results showed that UV-Vis spectra of α-TOC/CN nanoparticles complexes were significantly different during ultrasonic treatments, which indicate an increase in its interation. Interaction between α-TOC and casein at different molar concentrations resulted in a quenching of the intrinsic fluorescence at 280 nm and 295 nm. Moreover, by using FTIR deconvolution analysis and multicomponent peak modeling, the relatively quantitative amounts of α-helical and β-sheet in protein secondary structure were obtained, the self-assembly nanoparticles can improve stability of α-TOC by protecting from degradation caused by light and oxygen. Importantly, both the concentrations of α-TOC/CN nanoparticles were able to inhibit lipid emulsion oxidation.

Ultrasonic-assisted preparation of reduced graphene oxide-hydroxyapatite nanocomposite for bone remodeling

An ultrasonic-assisted preparation strategy was employed to synthesize in-situ hydroxyapatite-reduced graphene oxidenanocomposite (n-HA/rGO) as a potential biomaterial for bone regeneration under the osteoporotic condition. The results of Rietveld refinement indicated that the optimum crystallite size was 20.26 ± 0.52 nm following the ultrasonication at 400 W for 10 min. Well-dispersed plate-shaped HA nanocrystals with the mean thickness of 25 ± 2 nm were formed on the surface of rGO due to its anchoring tendency with calcium ions and hydrogen phosphate. By increasing the amount of power to 500 W, the intensity ratio of the D and G bands (ID/IG) increased due to the rise in the perturbation level in the rGO matrix and the chemical interactions between the rGO and HA.

Ultrasonic-assisted preparation of complex-shaped ceramic cutting tools by microwave sintering

Complex-shaped ceramic tools were prepared by ultrasonic-assisted molding technology and microwave sintering. A uniaxial ultrasonic vibration compaction system was designed. The effects of ultrasonic vibration and molding pressures on mechanical properties and microstructures of A2O3 and Al2O3/SiC complex-shaped milling cutters were investigated by simulations and experiments. The results indicated that the density was distributed unevenly within the green ceramic tool samples, especially poor in the tool edges. These drawbacks were well improved by ultrasonic-assisted molding technology and microwave sintering. Applying ultrasonic vibration during the compaction process of green ceramic tool samples could improve the densification, hardness and reduce the randomness of mechanical properties of the sintered ceramic tool materials, especially for the difficult-to-sinter composite ceramics (with poor density). For A2O3 ceramic tool, fully dense microstructure was achieved, and for Al2O3/SiC ceramic tool, the cutting edges showed better density than that of the interior body, which was beneficial to improve the abrasion resistance of cutting tool.

Ultrasonic-assisted preparation and characterization of magnetic ZnFe2O4/g-C3N4 nanomaterial and their applications towards electrocatalytic reduction of 4-nitrophenol.

Nanoball-structured ferromagnetic zinc ferrite nanocrystals (ZnFe2O4 NPs) entrapped with graphitic-carbon nitride (g-C3N4) was produced via straightforward and facile sonochemical synthetical technique (titanium probe; 100W/cm2 and 50KHz). The morphological (SEM), elemental (EDS), diffraction (XRD), XPS, and electrochemical studies (CV) have been carry out to verify the nanostructure and shape of the materials. The ZnFe2O4 NPs/g-C3N4 electrode (GCE) was constructed which displayed outstanding electrochemical ability towards toxic 4-nitrophenol (NTP). A sensitive, selective, reproducible, and durable electrochemical NTP sensor was developed by ZnFe2O4 NPs/g-C3N4 modified electrode. The modified sensor exhibited a high sensitivity and 4.17 nanomolars of LOD. It's greater than the LOD of previously reported NTP modified sensors. The real-time experiments of the modified electrochemical (ZnFe2O4 NPs/g-C3N4 electrode) sensor were successfully explained in various water (river and drinking) samples and its showed high standard recoveries. Therefore, sonochemical synthetical method and fabrication of modified electrode were developed this work based on environmental analysis of NTP sensor.

Ultrasonic-assisted preparation of amidoxime functionalized silica framework via oil-water emulsion method for selective uranium adsorption

The demand for low-cost adsorbent and method for efficient adsorption of metal ions for environmental and energy applications is highly required. The novel amidoxime functionalized silica framework (SiO2-AO) is prepared through a step by step process including ultrasonic-assisted oil–water emulsion method, surface sulfhydrylation, click reaction and modification of amidoxime. The hexane/water emulsion system in the presence of hexadecyltrimethylammonium bromide (CTAB) gives a large specific surface area of the precursor (SiO2-OH) and final products. The spectroscopic characterization combined with kinetics and isothermal studies reveals that the interaction between U(VI) and SiO2-AO is usually through coordination complexation. The adsorption behavior of SiO2-AO for U(VI) adsorption is explored through various batch methods including the effect of U(VI) concentration, pH, contact time and adsorbent dosage. It is revealed 99.9 ± 0.5% U(VI) adsorption occurs at pH = 8, which is close to the pH of seawater. The highest U(VI) adsorption capacity obtained from the Langmuir adsorption model is 955.8 mg g−1 at room temperature. The high removal rate (above 85%) at low U(VI) initial concentration (3 µg L-1), excellent selectivity of U(VI) in presence of coexisting ions and high adsorption efficiency of regenerated adsorbent in sixth cycle refer SiO2-AO as a potential adsorbent for U(VI) adsorption in the practical field.

Effect of Ultrasonic-Assisted Preparation of Powders on Synthesis of Rare Earth Zirconates

Effect of Ultrasonic-Assisted Preparation of Powders on Synthesis of Rare Earth Zirconates