Ultrasound Irradiation Time Research Articles

New insights into the improved contaminants removal in SBR by intermittently weak ultrasound

The combination of intermittently weak ultrasound and sequencing batch reactor was thoroughly investigated to elucidate the relationship between enhanced contaminants removal and activated sludge characteristics, microbial composition, and regulation of differentially expressed genes (DEGs). At 12 °C, irradiation with an ultrasound intensity of 9.68 W/L, an irradiation time of 10 min, and an interval time of 24 h led to significant increases in COD, NH4+−N, and TP removals with the rates of 93.10 ± 1.51%, 95.75 ± 0.76%, and 92.52 ± 0.95%, respectively. The intermittently weak ultrasound enhanced contaminants removal was primarily attributed to the stimulated microbial metabolism, in which the mechanical oscillation rather than free radical oxidation facilitated the loosening of activated sludge flocs and promoted microorganism proliferation. Elevating the ultrasound intensity or irradiation time could weaken the effect of enhancing ammonia−oxidizing bacteria activity and suppressing nitrite−oxidizing bacteria activity. The results revealed that intermittently weak ultrasound primarily affected the extracellular polymeric substances (EPS), with protein nitrogen playing a more significant role than polysaccharide within EPS against ultrasound−induced stress. Furthermore, ultrasound irradiation elevated the energy barrier in total−binding EPS interaction energy curves, thereby inhibiting activated sludge aggregation. Over prolonged operation, the relative abundance of the prevalent denitrifying genus Thauera increased by 90.3%, whereas that of the fully aerobic denitrifier and nitrite producer Dokdonella increased by 68.7%. The intermittently weak ultrasound induced enhancement of microbial metabolism−related DEGs pathways, which served as the main contributor to the improved contaminants removal. These findings provide novel insights into the mechanisms by which intermittently weak ultrasound enhances the effectiveness of biological wastewater treatment.

Degradation of diisopropyl methylphosphonate in aqueous solutions by ultrasonic irradiation combined with oxidation process

The degradation of diisopropyl methylphosphonate (DIMP) in aqueous solutions was studied using ultrasound irradiation with a fixed frequency of 26.2 kHz, following the first-order kinetic model. The study's primary goal was to determine the influence of the following experimental parameters: the pH (at different values of 2, 7 and 10), the initial concentration of DIMP (at different concentrations: 7, 14, 30, 50, 80 mg/L), the processing time (at different periods: 15, 30, 45, 60, 80, 90 min), and the concentration of the additive CCl4 (at different concentrations: 0.002, 0.004, 0.006, 0.008 mg/L). A DIMP removal efficiency of 98% from aqueous solution was obtained at pH 10 and 0.008 mg/L CCl4, after an ultrasound irradiation time of 45 min, pointing out the influence of the above-mentioned experimental parameters on the DIMP degradation process.

Ultrasound-assisted extraction (UAE) of antioxidant phenolics from Corchorusolitorius leaves: a response surface optimization

BackgroundBesides fibre production, Corchorusolitorius is considered a nutritional and medicinal plant in traditional medicine. Its leaves possess different antioxidant compounds and display various biological properties. This study optimized the ultrasound-assisted extraction (UAE) parameters like temperature, time, solvent concentration, and liquid–solid ratio for total flavonoids (TFC) and total polyphenols content (TPC) from leaves employing response surface methodology (RSM).ResultsFindings demonstrated that under the optimized conditions, the highest extraction yield of total flavonoids (7.17 mg QE/g DW) and total polyphenol content (13.92 mg GAE/g DW) were recorded with the ethanol concentration 70.92%, temperature 68.06 °C, liquid–solid ratio 48.80 mL/mg, and ultrasound irradiation time 37.20 min. The optimum value of TFC (6.96 mg QE/g DW) and TPC (13.38 mg GAE/g DW) from the experiment of verification of optimized conditions was close to the predicted value and significantly superior to the conventional heat reflux extraction (HRE). LC–MS and HPLC analysis of the optimized extract from UAE demonstrated the existence of six major phenolic compounds, including chlorogenic acid, isoquercetin, hyperoside, adhyperforin, 1,3-di-O-caffeoylquinic acid, and 3,4-di-O-caffeoylquinic acid. Furthermore, the antioxidant test of the UAE leaves extract revealed an excellent 2,2-diphenyl-1-picrylhydrazyl (DPPH•), 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•) and hydroxyl radical scavenging with IC50 values of 226.29, 199.53 and 402.02 µg/mL, respectively, compared to HRE with 336.31 µg/mL, 253.86 µg/mL, 520.08 µg/mL.ConclusionsThe developed optimization method could contribute to the good recovery of natural antioxidants from C. olitorius in the pharmaceuticals and food industries.Graphical

Extraction of polyphenols from hybrid Eucalyptus leaves using ultrasound: Parametric and antioxidant studies

AbstractIn the present study, a medicinal tree named hybrid Eucalyptus was chosen for the extraction of polyphenols from its leaves. Ultrasound has been used for extraction studies, whereas other conventional extraction methods were studied to validate the applied ultrasound assisted extraction method. Various experimental parameters like material to solvent ratio, solvents, and ultrasound irradiation time were employed to obtain the required condition for effective polyphenols extraction. The maximum total polyphenols achieved was 62.24 mg Gallic acid equivalent (GAE)/g of powdered leaves sample with material to solvent ratio of 1:30 and 50% ethanol as solvent with an ultrasonic bath whereas the maximum total flavonoid of 14.20 mg Quercetin equivalent (QE)/g of powdered leaves sample was obtained under the same experimental conditions. The gas chromatography mass spectroscopy (GC‐MS) study of the eucalyptus leaves extract had proved that it contains the required polyphenols of high medicinal value. Also, studies were performed to check 2,2‐diphenylpicrylhydrazyl (DPPH), ferric reducing anti‐oxidant power (FRAP) and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) radical scavenging potential of the leaves extract.

Facile one-pot rapid sonoelectrochemical synthesis of mesoporous magnetite nanospheres: A Chimie Douce approach

In this study, mesoporous Magnetite (Fe3O4) nanospheres have been synthesized quickly via facile sonoelectrochemical method. The scope of this study is to obtain high yield of active Fe3O4 nanoparticles in a tunable structural morphology with reduced cost, energy, and synthesis time without compromising its quality. The coupling of the electrochemical method with ultrasound could influence higher mass transfer rate, thereby leading to rapid formation of magnetite. Studies on understanding the role of additive and stabilizer have been carried out. Further, the influence of ultrasound amplitude and irradiation time has been examined. Under constant electrochemical parameters, the formation of magnetite of required properties is achieved with added additive and stabilizer under 60% ultrasound amplitude at 15 min of irradiation time. The prepared magnetite nanoparticles under optimized synthesis parameters were spherical in shape with a narrow size distribution of 30–80 nm, mesoporous in nature, and with a surface area of 121.87 m2g-1. The high value of saturation magnetization (65.33 emug−1) conjointly discloses the near superparamagnetic nature. The elemental composition of highly crystalline magnetite nanoparticles with good stability behavior has been demonstrated by deep characterization techniques.

Natural surfactant used as an additive in the homogenate-ultrasound-synergistic extraction of regaloside A and polysaccharides from Lilium lancifolium bulbs using Doehlert matrix design

In this study, 10 different natural surfactants were compared as additives for the simultaneous extraction of lipophilic regaloside A and water-soluble polysaccharides from tiger lily ( Lilium lancifolium Thunb.) bulbs by homogenate-ultrasound-synergistic extraction. Four significant factors that affect the yields of regaloside A and polysaccharides, including homogenate speed, ultrasound irradiation power, reaction temperature and ultrasound irradiation time, were screened by single-factor experiments and Plackett-Burman design and then optimized using Doehlert matrix design combined with a desirability function. The optimal extraction process conditions were obtained as follows: APG06 ( n -hexyl glucoside) surfactant concentration of 0.6%, homogenate speed of 20000 r/min, homogenate time of 6 min, liquid solid ratio of 20 mL/g, ultrasound irradiation power of 300 W, ultrasound irradiation time of 52 min, reaction temperature of 62.8 °C, and buffer and cavitation times of 1.5 s and 2.0 s, respectively. Under the optimal extraction conditions, regaloside A and polysaccharides yields of 2.797 ± 0.084 mg/g and 0.493 ± 0.016 g/g are obtained with relative standard deviations of 3.00% and 3.50%, respectively. The results of the method validation and comparison with the conventional method show that homogenate-ultrasound-synergistic extraction with APG06 as an additive is a green, efficient and energy-saving extraction method. Compared with the traditional extraction method, HUSE with APG06 as an additive is an effective method to extract regaloside A and polysaccharides from L. lancifolium bulbs. This study provides a reference for the development of green low carbon natural product extraction process. • Use homogenate-ultrasound-synergistic extraction of regaloside A and polysaccharides. • Alkyl polyglucoside was first added to extract phenolic acid glycerides (regaloside A). • 0.6% n -hexyl glucoside was chosen as the extraction additive. • Use combination of Plackett-Burman design and Doehlert matrix design. • Alkyl polyglucoside has obvious advantages on yield and safety compared with ethanol.

Spectroscopic investigation of ultrasound assisted sonochemical synthesis of BiOCl: Dy3+ nanophosphors for latent fingerprints visualization

A series of Dy3+ (1–9 mol%) doped BiOCl NPs were fabricated via ultrasound assisted sonochemical route using Aloe Vera (A.V.) gel as a bio-surfactant. Intense and sharp powder x-ray diffraction profiles confirm the matlockite-type tetragonal structure of BiOCl. The morphology of the nanophosphor was engineered by varying various experimental parameters, namely ultrasound irradiation time, pH level and A.V. gel concentration. The photoluminescence emission spectra of the prepared nanophosphor comprised of several intense peaks at ∼457, 549 and 614 nm, which are ascribed to 4F9/2→6H15/2 (Blue), 4F9/2→6H13/2 (Green) and 4F9/2→6H11/2 (Red) transitions of Dy3+ ions, respectively. The Judd–Ofelt intensity parameters Ωt (t = 2, 4) and other important radiative properties, such as total radiative transition probability, radiative life time and branching ratio of Dy3+ ions in the BiOCl were exploited using photoluminescent emission spectra. The photometric properties of the nanophosphors exhibit pure cool white light emission, which validate the potential applications of synthesized nanophosphor in phosphor converted white light emitting diodes. The optimized BiOCl:Dy3+ (5 mol%) nanophosphor was utilized as a powder dusting material to visualize LFPs on diverse surfaces. The stable optical properties and nano-regime of the nanophosphor permitted high resolution imaging enabling level I-III ridge arrangements details can be obtained. Therefore, the prepared nanophosphor has great potential for application in individual recognition.

Enhanced persulfate activated sono-catalytic degradation of brilliant green dye by magnetic CaFe2O4 nanoparticles: Degradation pathway study, assessment of bio-toxicity and cost analysis

In this study, CaFe2O4 nanoparticles were successfully synthesized by a chemical precipitation technique and applied in persulfate (PS) activated sono-assisted degradation of brilliant green (BG) dye from aqueous medium. Vibrating-sample magnetometer (VSM) analysis revealed that CaFe2O4 nanoparticles have manifested magnetic properties, which aided in effortless separation of nanoparticles from aqua matrix after treatment. More than 99% BG dye degradation was observed under dye concentration of 50 mg/L, catalyst dose of 0.5 g/L, PS dose of 200 mg/L and in an ultrasound (US) irradiation time of 15 min. However, US alone treatment had shown BG degradation of only 40.7% whereas the efficiency was enhanced to ∼89% upon addition of CaFe2O4 in US system. The PS activated sono-catalytic dye degradation (US + CaF + PS) process was optimized using response surface methodology (RSM) with four experimental variables, i.e., CaFe2O4 catalyst dose, PS dose, dye concentration, and sonication time. The quadratic model developed using RSM was found to be successful in optimizing the process variables (R2∼0.983). The scavenging effects observed with sodium chloride and sodium sulphate on US + CaF + PS process have reduced BG removal efficiency from 98% to 93% and 89%, respectively, which affirmed that the free radicals play the fundamental role in BG degradation. In US + CaF + PS process, BG dye (m/z ∼ 385) was degraded to simpler products having m/z ratio of 215, 113 and 73. Moreover, the microtox bioassay results indicated that the formed intermediate products were non-toxic in nature, i.e., toxicity of BG dye reduced from 90.58 to 1.24% after treatment with US + CaF + PS system. The treatment cost of BG dye solution varied between 131.85 and 922.02 USD/Kg of BG dye removed; however, the RSM based model has predicted the optimal BG dye removal of 99.57% with treatment cost of 330.82 USD/Kg of BG dye removed. Finally, the outcome of reusability study revealed that the synthesized nanoparticles were recyclable with a removal efficiency of 80.1% even after five consecutive cycles.

Antifungal activity of TiO2/AgBr nanocomposites on some phytopathogenic fungi.

TiO2/AgBr composites were synthesized by a simple ultrasonic strategy. Various instruments such as SEM, EDX, XRD, and FT‐IR were exploited to investigate their characteristics. Antifungal activities of the as‐obtained samples were assessed through the inactivation of Fusarium graminearum in the spore suspension method and mycelial growth inhibition of F. graminearum, Botrytis cinerea, and Sclerotinia sclerotiorum in the microdilution method. The results represented that the TiO2/AgBr samples possess higher antifungal activities on F. graminearum spores than the pure TiO2. The sample with 20 wt% silver bromide represented the highest inhibitory effect on the growth of F. graminearum so that all fungal spores were degraded in the initial times of the treatment process. The inactivation of fungal spores after 60 min was 35.2%, 97.8%, 98.9%, and 98.7%, in respect, for 5, 10, 20, and 30 weight percent of AgBr in the binary nanocomposites, while the inhibition rate was 13.4% for the pure TiO2. With increasing ultrasound irradiation time for more than 30 min, the inactivation rate constant decreased. It was also found that the antifungal activity of the nanocomposites without calcination was higher than those of the calcined materials. Considering the antifungal potential against phytopathogenic fungi and advantages such as simple synthesis and eco‐friendly nature, it seems that TiO2/AgBr nanocomposites can be used instead of synthetic chemicals after additional field investigations and mass production.

Boosted sono-oxidative catalytic degradation of Brilliant green dye by magnetic MgFe2O4 catalyst: Degradation mechanism, assessment of bio-toxicity and cost analysis

The magnetic MgFe2O4 nanoparticles (NPs) were fabricated via a facile co-precipitation technique and was comprehensively characterized by XRD, FTIR, SEM, EDX and VSM. The prepared NPs were used as catalyst in presence of ultrasound (US) irradiation to activate persulfate (PS) for generation of sulfate radicals (SO4·-) for boosted degradation of toxic Brilliant Green (BG) dye. Preliminary experiments revealed that highest BG dye degradation efficiency of 91.63% was achieved at MgFe2O4 catalyst dose of 1.0 g/L, PS dose of 300 mg/L, and initial dye concentration of 70 ppm within 15 min of US irradiation. However, only US, US in presence of PS oxidation and US in presence of MgFe2O4 catalyst have shown 20.2%, 83.6% and 45.0% of BG dye removal, respectively. Furthermore, response surface methodology (RSM) based central composite design (CCD) was executed to investigate the effect of interaction between independent variables such as MgFe2O4 catalyst dose (0.5–1.5 g/L), PS dose (150–350 mg/L), initial BG dye concentration (50–150 ppm) and US irradiation time (4–12 min). The RSM based quadratic model was used to predict the experimental data, and the prediction accuracy was confirmed by analysis of variance (R2 = 0.98). The established RSM model has predicted the optimum experimental conditions as MgFe2O4 catalyst dose of 0.75 g/L, PS dose of 300 mg/L, initial dye concentration of 75 ppm and sonication time of 10 min. Subsequently, the treatment cost analysis was performed for all thirty experimental runs of CCD, and the RSM predicted response was found to be evidently optimum as this has delivered best economic condition (140 $/kg of BG removed) with respect to relative dye removal (%). COD removal and residual sulfate analysis have demonstrated satisfactory reduction of COD (90.31%) as well as sulfate ions (42.87 ppm) in the dye solution after treatment. Results of degradation pathway analysis portrayed the transformation of BG molecule (M/Z ratio 385) into simpler fractions with M/Z ratio of 193, 161, 73, and 61. Moreover, the toxicity analysis revealed that sono-catalytically activated PS system has efficiently reduced the toxicity level of BG dye from 93.9% to 5.13%.

Effects of ultrasound irradiations time over Ni–Mo/γ-Al2O3 catalyst synthesis for 1,3 – Propanediol selectively via aqueous phase reforming of glycerol

In general, aqueous phase reforming (APR) is used to convert glycerol into 1,3-propanediol (1,3-PDO), nonetheless, studies have shown a low selectivity of 1,3-PDO. Therefore, this study aims to optimize the selectivity of 1,3-PDO by varying the ultrasound (Us) irradiation process time between 10 and 50 ​min during catalyst preparation. This is to investigate the effect on the physiochemical properties and activity of the catalyst. Ni–Mo/Al2O3 catalysts were prepared using a sonochemical method and was characterized using Brunauer-Emmett-Teller (BET), X-ray Powder Diffractometer (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Hydrogen Temperature-programmed Reduction (H2-TPR). Characterization results revealed that there were significant improvements in physiochemical properties of catalysts by varying the Ultrasound (Us) irradiation time. Subsequently, all catalysts were screened using APR of glycerol for 1,3-PDO production using an Autoclave PREMEX reactor and the liquid products were analyzed to determine the selectivity of 1,3-PDO. From all the results, findings revealed that the catalyst prepared with 10 ​min of Us radiation time demonstrated a high catalytic performance and physiochemical properties while producing the highest concentration of 1,3-PDO with 954 ​ppm with a conversion of 38.6%. The outcomes have shown that sonochemical irradiation time conversely effects on the physiochemical properties of the catalysts and 1,3-PDO production.

Sonocatalytic performance of eggshells loaded with transition metal ions for decolorization of crystal violet dye

In this study, divalent transition metal ions namely Fe(II), Co(II), Ni(II) and Cu(II) were loaded on the eggshells by a simple impregnation method and characterized by UV–vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) surface area analyzer, X-ray photoelectron spectrometer (XPS), and X-ray diffraction (XRD) techniques. The metal ions loaded eggshells were investigated for the sonocatalytic degradation of a triarylmethane dye, crystal violet (CV) under ultrasonic irradiation. The experimental conditions like sonocatalyst dosage, dye concentration and ultrasound irradiation time were optimized based on decolorization of CV. The results evidenced an excellent sonodegradation performance of Fe(II) loaded eggshell towards CV, within 30 min, when compared to other metal ions loaded eggshell. The sonodegradation mechanism has been proposed and the recycle capacity upto 5 cycles was investigated with only ∼8 % decrease in degradation efficiency.

Effect of diagnostic ultrasound on corneal apoptosis in rats

Purpose: To investigate the effect of diagnostic ultrasound on corneal apoptosis in rats.Methods: 24 male rats were randomly divided into 4 groups: control group, 10, 20 and 30 min group. The eyeballs of rats were irradiated continuously for different time lengths by Siemens ACUSON S2000 color Doppler ultrasound diagnostic instrument. 24 hours later, the animals were killed and the corneas were taken for Tunel apoptosis detection. The apoptosis rates of corneal epithelial cells, stromal cells and endothelial cells were calculated.Results: Apoptotic cells were detected in corneal epithelial cells, stromal cells and endothelial cells of normal rats. There was no significant difference between the 10 min group and the control group (P>0.05). The apoptosis rate of 20 min and 30 min groups was significantly higher than that of the control group. With the extension of irradiation time, the apoptosis rate of corneal epithelial cells, stromal cells and endothelial cells increased.Conclusion: 20 min of rat eyeball irradiated by diagnostic ultrasound can increase the apoptosis of corneal cells, and the apoptosis is aggravated with the prolongation of ultrasound irradiation time.
 Keywords: Cornea; Ultrasonography; Apoptosis; Epithelial cells

Effect of Ultrasound Irradiation on the Synthesis of Hydroxyapatite/Titanium Oxide Nanocomposites

Bioceramic materials, such as hydroxyapatite, Ca10(PO4)6(OH)2, (HAp), can be chemically bound to bone tissue; since they are bioactive and biocompatible. HAp, titanium oxide (TiO2), and hydroxyapatite/titanium oxide (HAp/TiO2) nanocomposite nanoparticles were obtained by ultrasound irradiation assisted by sol-gel and co-precipitation methods at different time intervals, using Ca(NO3)2•4H2O, (NH4)2HPO4, and TiOSO4•xH2O as calcium, phosphorus, and titanium sources, respectively. HAp, TiO2, and HAp/TiO2 nanocomposite powders were characterized by X-ray Diffraction (XRD) and Raman Spectroscopy. The percentages of anatase phase for TiO2 and of monoclinic and hexagonal phases for HAp were quantified by Rietveld refinement. Furthermore, sample crystallinity in each material was enhanced by increasing the ultrasound irradiation time. The nanoparticle shape was semi-spherical, agglomerated, and between 17 and 20 nm in size. The agglomeration of particles in the samples was corroborated with a Field Emission Scanning Electron Microscope (FESEM).

Comprehensive study of loading and release of sodium valproate drug molecule from functionalized SBA-15 with aminopropyl groups through Co-condensation modification method

Mesoporous Santa Barbara amorphous (SBA-15) was functionalized through co‐condensation using tetraethoxy orthosilicate and 3-aminopropyltriethoxysilane in the presence of the copolymer Pluronic P-123 (EO20PO70EO20) as a pore‐directing agent under an acidic condition. A comprehensive study of the sodium valproate (SV) loading and release was carried out on SBA-15 and functionalized SBA-15. The functionalized and drug loaded mesoporous materials were comprehensively characterized using X-ray diffraction, nitrogen adsorption isotherms, FTIR, TGA, SEM, and TEM techniques. The Box-Behnken design was applied to optimize the variables of drug loading time, ultrasound irradiation time, and carrier dose. Results indicated that the COO− group of SV was associated with the amine group of functionalized SBA-15. SV release was performed in HCl 0.01 M, acetate buffer solution pH = 4.5, and phosphate buffer solution pH = 6.8. The release date indicated that the loading of the aminopropyl group in SBA-15 influenced the release properties of SV. Eventually, the drug release kinetic models were investigated for both carriers.

Efficacy of low intensity ultrasound on fermentative activity intensification and growth kinetic of Leuconostoc mesenteroides

The effects of low intensity ultrasound (20 % and 30 % amplitudes for 3 min and 5 min) on the growth and fermentative activities of Leuconostoc mesenteroides (PTCC 1663) were studied. The plate count, cell membrane permeability, and specific growth rate were increased in the ultrasonicated samples by 0.41−0.84 log CFU/mL, 8.83–28.48 %, and 12.7–35.5 %, respectively, compared to the reference samples. In general, ultrasound influenced the fermentative activities of Leu. mesenteroides: an increase in pH dropping rate, acidification, β-galactosidase activity, proteolysis, and consumption of substrate, largely depending on ultrasound amplitude and irradiation time. This was accompanied by an increase in the organic acids production including lactic, acetic, and citric acids by Leu. mesenteroides, however, propionic acid was not detected in neither the control nor the sonicated samples. Findings of this study offer a promising approach, which would accelerate the growth and fermentative activities of starter cultures and may successfully be employed in fermentation industries.

Ultrasound-assisted fermentative production of Polyhydroxybutyrate (PHB) in Cupriavidus necator

The conventional polymers (polyethylene, polypropylene, polystyrene, etc) are non-degradable and exhibit many hazardous effects on the environment. Due to their bio incompatibility and accumulation in nature, there is a need to produce environment-friendly biodegradable polymers. Polyhydroxybutyrate is one of the biodegradable biopolymers produced by a microorganism Cupriavidus necator in order to survive the stress condition. In this study, the effect of ultrasound to intensify the productivity of biopolymer was studied. Different ultrasound parameters, mainly the effect of ultrasound power, duty cycle, ultrasound irradiation time on the productivity of PHB were studied using the one-factor-at-a-time method. Intracellular PHB was extracted using chloroform as a solvent, and analysis was carried out using GC–MS, FT-IR analytical techniques for the detection of PHB. The highest productivity of 0.2155 ± 0.0049 g/100 mL (1.7 g PHB g−1 dry cell wt−1) is reported when a substrate was irradiated with ultrasound at 22 kHz frequency, 50 W power, 10% duty cycle and 10 min of irradiation time with a constant cycle time of 1 min.

Synthesis of shape-controlled Pd nanocrystals on carbon nanospheres and electrocatalytic oxidation performance for ethanol and ethylene glycol

Palladium nanocrystals (Pd NCs) on carbon nanospheres (CNS) are the most important electrocatalysts especially in a direct alcohol fuel cell (DAFC). The shape and size-controlled of Pd NCs are crucial to their electrocatalytic activity. For the first time, we focused on the effect of ultrasound irradiation time interval to build the morphology and size-controlled of Pd NCs. Notably, the functional groups (COO−, and SO3−) situated on the edges and surfaces of CNS act as an effective capping agent and supporting materials for the growth of various morphology of Pd NCs on CNS surface. In this case, there is no need for an extra stabilizer or reducing agent for the preparation of Pd NCs. The catalytic activity of various Pd-CNS nanocomposites was investigated systematically using an electrochemical workstation. The results have shown that small-sized Pd NCs with a spherical shape had an enhanced activity and stability for alcohol oxidation relative to those of hexagonal Pd NCs and commercial Pd/C. Especially, the spherical Pd-CNS show mass activity 1.6 and 2.8 folds higher than that of hexagonal Pd-CNS and commercial Pd/C, respectively, and significantly maintain high activities after 1000 cycles of intensive durability test.

Ultrasound-Assisted Extraction of Taxifolin, Diosmin, and Quercetin from Abies nephrolepis (Trautv.) Maxim: Kinetic and Thermodynamic Characteristics.

Extraction behaviors of the 3 flavonoids taxifolin, diosmin, and quercetin have been investigated in Abies nephrolepis leaves and bark. The following operation parameters—ethanol volume fraction, liquid–solid ratio, temperature, ultrasound irradiation power and time, and ultrasound frequency—were varied to study their effect on the yield of the 3 flavonoids during extraction. The results showed that a low extraction efficiency occurred at 293.15 K due to slow kinetics, while the situation was significantly improved at 333.15 K. The kinetic data for the extraction yields of the 3 flavonoids achieved good fits by the first-order kinetic model. From the thermodynamic analysis results, we realized that the ultrasound-assisted extraction of taxifolin, diosmin, and quercetin from the leaves and bark of A. nephrolepis was a spontaneous and endothermic process in which the disorder increased (ΔG0 < 0, ΔH0 > 0, and ΔS0 > 0). According to the response surface methodology (RSM) analysis, under the optimal operation conditions (ethanol concentration of 50%, liquid–solid ratio of 20 mL/g, frequency of 45 kHz, extraction time of 39.25 min, ultrasound irradiation power of 160 W and temperature of 332.19 K), the total yield of the 3 flavonoids were 100.93 ± 4.01 mg/g from the leaves of A. nephrolepis (with 31.03 ± 1.51 mg/g, 0.31 ± 0.01 mg/g, 69.59 ± 2.57 mg/g for taxifolin, diosmin, and quercetin, respectively), and under the optimal operation conditions (ethanol concentration of 50%, liquid–solid ratio of 20 mL/g, frequency of 45 kHz, extraction time of 36.80 min, ultrasound irradiation power of 150 W and temperature of 328.78 K), 16.05 mg/g ± 0.38 mg/g were obtained from the bark of A. nephrolepis (with 1.44 ± 0.05 mg/g, 0.47 ± 0.01 mg/g, 14.14 ± 0.38 mg/g for taxifolin, diosmin, and quercetin, respectively), which were close to the prediction values.

Production of Sharp-Edged and Surface-Damaged Y2BaCuO5 by Ultrasound: Significant Improvement of Superconducting Performance of Infiltration Growth-Processed YBa2Cu3O7-δ Bulk Superconductors.

Growth and physical properties of bulk REBa2Cu3O7−δ (REBCO) superconductors fabricated by the infiltration growth (IG) method strongly depend on the initial size and morphology of the RE2BaCuO5 (211) particles. The present work details the novel method we developed for producing sharp-edged and surface-damaged 211 particles to be added to the REBCO bulks. We employed high-energy ultrasonic irradiation for pretreating the 211 particles and fabricated high-performance bulk single-grain YBa2Cu3O7−δ (YBCO) superconductors via the top-seeded IG process. Increasing the ultrasound irradiation power and time duration mechanically damaged the surface of the 211 particles, producing more fine and sharp edges. Systematic investigations of the microstructural properties of the final YBCO bulks indicated that the size and content of the 211 particles gradually decreased without any additional chemical doping. The effective grain refinement and improved interfacial defect densities enhanced the critical current density by a factor of two at 77 K and self-field as compared to a YBCO sample fabricated without any pretreatment. A maximum trapped field of 0.48 T at 77 K was obtained for a sample (20 mm diameter) with 211 particles treated for 60 min and 300 W ultrasound radiation. The effectiveness of the novel method is demonstrated by the superior performance of the YBCO bulk samples prepared as compared to bulk samples fabricated with the addition of Pt and CeO2. This method is novel, cost effective, and very convenient, maintaining high sample homogeneity, and is free of chemical contaminants as compared to other methods which significantly affect the properties of all REBCO bulk products grown by sintering, melt growth, and IG methods.