Influence Of Ultrasound Irradiation Research Articles

Ultrasound-assisted ionic exchange and solvothermal synthesis of Bi2MoO6/Bi2SiO5/Bi12SiO20 ternary nanophotocatalysts for visible light-driven degradation reaction of pharmaceutical pollutants

The novel ternary Bi2MoO6/Bi2SiO5/Bi12SiO20 nanophotocatalyst as a cascaded pseudo-type II configuration was synthesized at different values of Si and Bi2MoO6 via a simultaneous ultrasound-boosted ionic exchange-solvothermal approach to degrade fluoroquinolones contaminants under solar light. The influence of ultrasound irradiation was assessed and Bi2MoO6/Bi2SiO5/Bi12SiO20 (Si-2)-U sample was designated as the most effective sample with the best performance. To illustrate the efficacious performance of the referred sample, PL, XRD, UV–Vis DRS, FESEM, TEM, BET-BJH analyses were carried out. Regarding the phase diagram obtained by XRD analysis, the amount of Bi2MoO6, Bi2SiO5, and Bi12SiO20 for Bi2MoO6/Bi2SiO5/Bi12SiO20 (Si-2)-U was 27%, 13% and 60%, respectively. In contrast, without ultrasound irradiation, these amounts were obtained which are 39.6%, 37.6%, and 22.8% for Bi2MoO6, Bi2SiO5, and Bi12SiO20, correspondingly. BET-BJH technique displayed 20.8 m2/g surface area, 0.1805 cm3/g pore volume, and 34.7 nm mean pore diameter. DRS presented two absorption edges for the best nanocomposite at 414.7 (2.99 eV) and 489.3 (2.53 eV) nm. In addition, morphology observations proved the microcube architecture covered by nanosheets assembled of spherical nanoparticles. The photodegradation of levofloxacin, ofloxacin and ciprofloxacin over Bi2MoO6/Bi2SiO5/Bi12SiO20 (Si-2)-U was 96.9%, 83.6%, and 70.3%, subsequently that the kinetic constant was 2.6 times of nanocomposite synthesized without the usage of ultrasound energy. The perfect performance and suitable reusability of Bi2MoO6/Bi2SiO5/Bi12SiO20 (Si-2)-U nanophotocatalyst can be attributed to the proper composition and presence of ultrasound energy during synthesis, leading to the operative mass transfer, pollutant adsorption, light harvesting/diffusion, and charge separation.

The Influence of Ultrasound on the Growth of Nannochloris sp. in Modified Growth Medium.

The influence of ultrasound irradiation on the algal biomass productivity as well as its oil content and fatty acids profile, grown in a modified Zarrouk medium, i.e., deproteinized whey waste solution, was investigated. The algal samples (Nannochloris sp. 424-1 microalgae) were grown for 7 days in a thermostated incubator at 28 °C, shaken under continuous light. During this period, the algal biomass was subjected to induced stress by ultrasonic irradiation at different powers and sonication time. The obtained results demonstrate that ultrasound stressing of algae biomass has a positive effect on both the quantity of biomass and the oil obtained, also causing a shift in fatty acid composition by increasing the proportion of C16 and C18 polyunsaturated fatty acids. A low dosage level of exposure to the ultrasound led to algal biomass increase as well as lipid accumulation. For both types of irradiation modes which were investigated, daily and only initial irradiation, the beneficial effect of the ultrasound decreases as the exposure time increases and the excessive sonication becomes detrimental to microalgae growth.

Collagenase-Loaded H-TiO2 Nanoparticles Enhance Ultrasound Imaging-Guided Sonodynamic Therapy in a Pancreatic Carcinoma Xenograft Model via Digesting Stromal Barriers.

Sonodynamic therapy (SDT), a noninvasive therapy that relies on sonosensitizers and generates reactive oxygen species (ROS), has attracted considerable attention in the treatment of pancreatic cancer. However, being surrounded by dense stromal barriers, pancreatic cancer exhibits high interstitial fluid pressure (IFP) and hypoxia in the tumor microenvironment (TME), resulting in poor SDT efficacy. Collagenase-loaded hollow TiO2 (Col-H-TiO2) nanoparticles (NPs) capable of degrading stromal barriers and producing sufficient ROS production were synthesized in this study. After administration of NPs in the patient-derived xenograft (PDX) model, ultrasonic irradiation-released collagenase degraded tumor matrix fibers, decreased intratumoral IFP, and enhanced the penetration and retention of NPs within tumor tissues. Moreover, the NPs accumulated within the tumor not only generate abundant ROS under the influence of ultrasound irradiation but also improve intratumoral ultrasound signal, providing ultrasonic imaging-guided highly effective SDT for pancreatic cancer. In conclusion, this research improves the SDT technique and enhances the visualization of pancreatic cancer by remodeling the TME and is a promising strategy for further clinical applications.

Application of TiO2 and Nb2O5 for ultrasonic degradation of Rhodamine-B

The degradation of Rhodamine-B (RB) in aqueous solutions was investigated in this study under the influence of ultrasound irradiation (20 kHz) in the presence of titanium dioxide (TiO2) and niobium pentaoxide (Nb2O5) heterogeneous catalysts. The effects of different factors such as catalyst quantity (0.25, 0.5, 0.75, 1.0, 1.25 g/L), initial concentration of RB (10, 20, 30, 40, 50 ppm) and pH (3, 5, 7, 9, 11) were examined. The optimal catalyst dose was found to be 1.25 g/L of TiO2, Nb2O5 and the maximum percentage of RB degradation was observed at pH 3 for the TiO2 and Nb2O5 catalysts. In the presence of TiO2 and Nb2O5, the percentage degradation of RB under ultra-sonication in aqueous solutions is up to 85% and 81% respectively.

Influence of ultrasound irradiation on transient solidification characteristics in DC casting process: Numerical simulation and experimental verification

It is well known that solidification of molten metals occurs under the influence of transient unsteady phenomena, which are difficult to control in actual casting operation. Examples include buoyancy flows, natural heat convection, repeated remelting and solidification in mushy zone and solid shell at the mold interface. This paper presents the results suggesting that ultrasound waves, irradiated into the hot-top mold offers an attractive way to control the transient phenomena in DC casting of aluminum alloy billets. A novel mathematical model was developed to simulate the DC casting with considering transient melt flow, heat transfer, ultrasound propagation, acoustic streaming and solidification. It was found that ultrasound irradiation alters the solidification behavior of melt and sump evolution especially in the earlier stage of casting, however as the billet length increases, the sump profile becomes almost the same for both the ultrasonic and conventional castings. In this condition, the casting speed becomes the key parameter influencing the sump evolution and mushy zone volume. The results reveal that ultrasound-driven acoustic streaming and turbulent oscillations result in a suppression of buoyancy flow in the sump and lead to an increase of frequency of the melt temperature oscillations at the solidification interface. One of the useful results of these phenomena can be a more frequent repetition of remelting/solidification cycle and improvement of the billet quality, particularly the billet surface morphology. The effect of ultrasound irradiation on the billet morphology was verified experimentally using a pilot DC caster.

The effect of ultrasound irradiation on the physicochemical properties and α-glucosidase inhibitory effect of blackberry fruit polysaccharide

In this study, the influence of ultrasound irradiation on the characterization and α-glucosidase inhibitory effect of polysaccharide from blackberry fruit (BBP, molecular weight of 591.39 kDa) was investigated. After degraded, BBP-8, BBP-16 and BBP-24 three fractions were obtained with molecular weight of 363.93, 249.51 and 177.42 KDa, respectively. Moreover, compared with the particle size of BBP (1070.5 nm), that of BBP-8, BBP-16 and BBP-24 were decreased to 679.9, 548.8 and 395.4 nm, respectively. However, the monosaccharide composition test, FT-IR, and tertiary structure analysis all indicated that the ultrasound did not destroy the primary structure of the original polysaccharide. In addition, the degraded polysaccharide (BBP-24) exhibited the stronger α-glucosidase inhibitory activity than that of BBP. By fluorescence spectrum and circular dichroism spectrum analysis, we found that the polysaccharide could induce the structure change like rigidity structure (α-helixe) and loop structure (random coil) of α-glucosidase to inhibit its activity by binding to the α-glucosidase. The polysaccharide with different molecular weight showed different binding capacity which was related to its inhibitory effect on the α-glucosidase. In general, the results suggested that appropriate degradation was benefit for the enhancement of the inhibitory effect on α-glucosidase of blackberry polysaccharide, and ultrasound irradiation was a green and efficient method to produce bioactivity-added polysaccharide for use in the functional food.

The Influence of Ultrasound Irradiation on Falling Sphere in Pseudo-Plastic Fluid

Ultrasound effects on the motion of a falling sphere in water (i.e. Newtonian fluid) and in PolyAcrylAmide (PAA) solution (i.e. non-Newtonian shear-thinning fluid) are experimentally investigated via an image processing technique. The falling speed in water is confirmed to be almost irrespective of the frequency or amplitude in the applied ultrasound, while that in PAA solution is found to be higher with increasing the ultrasound intensity. In consideration of pseudo-plastic factors estimated by various velocity and length scales involved in the system, we consider that the mechanism to enhance the falling speed has the influence of viscosity in the acoustic boundary layer and its thickness.

Effects of ultrasonic irradiation on the synthesis, crystallization, thermal and dissolution behaviour of chloride-intercalated, co-precipitated CaFe-layered double hydroxide

The output power (30–150 W) and the periodicity (20–100%) of ultrasound emission were varied in a wide range to regulate and improve the crystallization process in the commonly used co-precipitation technique of chloride-intercalated CaFe-layered double hydroxides. The influence of ultrasound irradiation on the as-prepared materials was studied by X-ray diffractometry, dynamic light scattering, UV–Vis–NIR diffuse reflectance spectroscopy, specific surface area measurement, pore size analysis, ion-selective electrode potentiometric investigations and thermogravimetry. Additionally, structural alterations due to heat treatment at various temperatures were followed in detail by Fourier-transform infrared and X-ray absorption spectroscopies as well as scanning electron microscopy. The ultrasonic treatment was capable of controlling the sizes of primarily formed (from 19 nm to 30 nm) as well as the aggregated (secondary) particles (between 450 nm and 700 nm), and thus modifying their textural parameters and enhancing the incorporation of chloride anions into the interlamellar space. For the first time, the optical energy gap of CaFe-LDH was reported here depending on the nature of applied stirring (4.18–4.34 eV). The heat-treatment investigations revealed that the layered structure was stabile until 200 °C, even at the atomic level.

Sono-dispersion of MgO over Al-Ce-doped MCM-41 bifunctional nanocatalyst for one-step biodiesel production from acidic oil: Influence of ultrasound irradiation and Si/Ce molar ratio

MCM-41 is a mesoporous silicate with hydrophobic structure which is a good candidate as catalyst support in biodiesel production, with high specific area (more than 1100 m2/g) and high thermal stability. In this study the hydrothermal stability and acidic property of Al-MCM-41 were improved by addition of Ce element into its structure with various amounts of Si/Ce molar ratio. Then it was loaded by magnesium with two different procedures: customary impregnation and Sono-dispersion. The following techniques were utilized to characterize the synthesized nanocatalysts: EDX, FTIR, FESEM, DRS, BET and XRD. The catalytic performance of bifunctional nanocatalysts for biodiesel production from acidic oil was analysed, while four operational parameters were fixed as: catalyst charge equal to 5 wt%, reaction temperature equal to 70 °C, reaction duration equal to 6 h and methanol/oil molar ratio equal to 9. Generally, the obtained results revealed that the conversion and the quality of produced biodiesel were increased significantly by increasing Ce amount of catalysts up to Si/Ce = 25 and also the sonicated sample represented a better reusability compare to non-sonicated one. Among the prepared samples, Mg/ACM-U (Si/Ce = 25) achieved the maximum conversion and high reusability for biodiesel production reaction after fifth cycle.

Sono-dispersion of calcium over Al-MCM-41used as a nanocatalyst for biodiesel production from sunflower oil: Influence of ultrasound irradiation and calcium content on catalytic properties and performance

Abstract In this paper, the acidity of MCM-41 was improved by Al addition (Si/Al molar ratio of 50) and it was used as support in nanocatalysts with various loadings of calcium (10, 20 and 30 wt %) for biodiesel production. The catalysts were synthesized by two methods: impregnation and sono-dispersion. The synthesized samples were characterized by XRD, FESEM, EDX, TEM, BET and FTIR analysis. The XRD patterns of the samples demonstrated formation of the crystalline structure of MCM-41 and CaO. The FESEM images of the samples proved the nanoscale of catalysts and along with EDX and TEM analysis showed a better dispersion of calcium on support for ultrasonic irradiated sample compared to impregnated one. The performance of nanocatalysts was examined under constant conditions (Temperature of 70 °C, Methanol/Oil ratio of 12 and catalyst loading of 10 wt %). The result showed that the conversion of transesterification reaction and following that the quality of produced biodiesel was increased significantly by increasing the calcium amounts in catalysts. Furthermore, for two samples with the same amount of calcium loading, the sonicated sample showed a higher conversion. Among all of the samples Ca(30)/Al-MCM-41(U) showed the maximum conversion for biodiesel production reaction.

Effects of ultrasound irradiation on the characterization and bioactivities of the polysaccharide from blackcurrant fruits

In this study, the influence of ultrasound irradiation on the characterization and bioactivities of the polysaccharide from blackcurrant fruits (BCP, molecular weight: Mw = 3.26 × 104 kDa) was investigated. Two degraded polysaccharides (U-400, Mw = 1.89 × 104 kDa, and U-600, Mw = 1.32 × 104 kDa) were obtained by different ultrasound powers of 400 W and 600 W, respectively. Compared with BCP, U-400 and U-600 showed 63.52% and 68.85% reductions in the particle size (Zavg), respectively; moreover, the dynamic viscosity of BCP was reduced by 27.88%, and 33.63%, separately. The reducing sugar content and thermal stability increased with the increase of ultrasound intensity. The degraded polysaccharides contained the same monosaccharide species as those of BCP but at different molar ratios. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic analysis confirmed that the degraded polysaccharides and BCP exhibited the similar structural features, which were mainly composed of six glycosidic bonds. A reduction in surface area of the flake-like structure was observed in the degraded polysaccharides compared to that of BCP, and they had no triple helix structure. Furthermore, the precise structural characteristics of U-600 were identified by 2D NMR analysis. The results of the bioactivity assays indicated that the ultrasound irradiation could evidently enhance the antioxidant (hydroxyl and superoxide radicals scavenging, lipid peroxidation inhibition, and DNA damage protection activities), α-amylase and α-glucosidase inhibition activities of BCP. These activities increased in the order of U-600 > U-400 > BCP. In particular, the DNA protection and α-amylase inhibition activities for U-600 were 52.19 ± 1.34% and 75.98 ± 0.77%, respectively, which were 2 times higher than those of BCP. U-600 prepared with the higher-intensity ultrasound exhibited the best physicochemical properties and bioactivities among the three polysaccharides. These results suggested that ultrasound irradiation was an efficient, green method to produce value-added polysaccharide for use in functional food or medicine.

Synthesis of butyl esters via ultrasound-assisted transesterification of macaúba (Acrocomia aculeata) acid oil using a biomass-derived fermented solid as biocatalyst

Enzymatic synthesis of fatty acid esters from macaúba (Acrocomia aculeata) acid oil was studied in a solvent-free system using a fermented and dry babassu (Orbygnia oleifera) cake with lipase activity from Rhizomucor miehei, named solid enzymatic preparation (SEP). The reactions were carried out under the influence of ultrasound irradiation and using different alcohols. Higher ester yields were obtained using butanol as acyl acceptor. An experimental design was used to evaluate the effects of SEP concentration (2–12Ug−1 based on oil mass), butanol to oil molar ratio (3:1–12:1) and amount of water (0–10% based on oil mass) on the reaction yield. Fatty acid butyl ester (FABE) content around 80% was achieved after 70h with a substrate molar ratio of 5.47:1, water content of 10% as oil mass and amount of biocatalyst of 12Ug−1 as oil mass, at 40°C. It was possible to obtain high yields using a low-cost biocatalyst, produced using an agricultural waste, and low-cost raw-material, making biocatalytic route competitive compared to chemical route.

Ultrasound assisted enzyme catalyzed hydrolysis of waste cooking oil under solvent free condition

The present work demonstrates the hydrolysis of waste cooking oil (WCO) under solvent free condition using commercial available immobilized lipase (Novozyme 435) under the influence of ultrasound irradiation. The process parameters were optimized using a sequence of experimental protocol to evaluate the effects of temperature, molar ratios of substrates, enzyme loading, duty cycle and ultrasound intensity. It has been observed that ultrasound-assisted lipase-catalyzed hydrolysis of WCO would be a promising alternative for conventional methods. A maximum conversion of 75.19% was obtained at mild operating parameters: molar ratio of oil to water (buffer pH 7) 3:1, catalyst loading of 1.25% (w/w), lower ultrasound power 100W (ultrasound intensity – 7356.68Wm−2), duty cycle 50% and temperature (50°C) in a relatively short reaction time (2h). The activation energy and thermodynamic study shows that the hydrolysis reaction is more feasible when ultrasound is combined with mechanical agitation as compared with the ultrasound alone and simple conventional stirring technique. Application of ultrasound considerably reduced the reaction time as compared to conventional reaction. The successive use of the catalyst for repetitive cycles under the optimum experimental conditions resulted in a loss of enzymatic activity and also minimized the product conversion.

Effect of electrolyte agitation on anodic titanium dioxide (ATO) growth and its photoelectrochemical properties

Nanoporous anodic titanium dioxide (ATO) layers were synthesized at 20°C by a three-step anodization carried out at the constant voltage of 30V in the electrolyte based on an ethylene glycol containing fluoride ions. The effect of stirring speed on the growth of anodic TiO2 layers was investigated in the range of 0–500rpm. It was found that the thickness of grown oxide layer, and consequently, the rate of oxide formation depend directly on the stirring speed. The morphological characterizations – porosity, cell density, cell size, oxide thickness, percentage of defective cells and their arrangement in ATO layers were correlated with different electrolyte stirring speeds. The influence of ultrasound irradiation during ATO formation and extended time of third anodization on photoelectrochemical response of ATO electrodes was studied. Photoelectrochemical properties of received anodic oxide layers were measured in a 0.1M KNO3 aqueous solution under the applied potentials of 0–1000mV vs. SCE. The generated photocurrents were studied at the wavelength range of 300–400nm. The highest values of generated photocurrents were observed at 350nm. For all studied stirring speeds, photoconversion efficiencies, determined as incident photon-to-current efficiency (IPCE), were calculated.

Kinetics of ultrasound-assisted enzymatic biodiesel production from Macauba coconut oil

This work reports the production of fatty acid ethyl esters (FAEE) by means of Macauba (Acrocomia aculeata) coconut oil (MCO) solvent-free enzymatic transesterification reactions using a commercial immobilized lipase (Novozym 435) under the influence of ultrasound irradiation. An experimental design was used to evaluate the effects of temperature (40–70 °C), enzyme (5–20 wt%) concentration, oil to ethanol molar ratio (1:3–1:10) and output irradiation power (40–70 % of the maximum supply value) on the reaction yield. Besides, a kinetic study varying the enzyme concentration was also carried out. Results show that ultrasound-assisted lipase-catalyzed transesterification of MCO with ethanol in solvent-free system might be a potential alternative route to conventional alkali-catalyzed and/or traditional enzymatic methods, as reaction yields around 70 wt% were obtained at mild irradiation power supply (∼ 132 W), and temperature (65 °C) in a short reaction time, 30 min. Reutilization of enzyme showed that it may be advantageously employed up to 5 reuse cycles.

Enzyme-catalyzed production of biodiesel by ultrasound-assisted ethanolysis of soybean oil in solvent-free system.

This work reports the transesterification of soybean oil with ethanol using a commercial immobilized lipase, Novozym 435, under the influence of ultrasound irradiation, in a solvent-free s. The experiments were performed in an ultrasonic water bath, following a sequence of experimental designs to evaluate the effects of temperature, enzyme and water concentrations, oil to ethanol molar ratio and output irradiation power on the reaction yield. Besides, a kinetic study varying the substrates molar ratio and enzyme concentration was also carried out. Results show that ultrasound-assisted lipase-catalyzed transesterification of soybean oil with ethanol in solvent-free system might be a potential alternative route to conventional alkali-catalyzed and/or traditional enzymatic methods, as high reaction yields (~78wt%) were obtained at mild irradiation power supply (~132W), and temperature (63°C) in a relatively short reaction time, 1h. Additionally, a study regarding the enzyme reuse was carried out at the experimental condition that afforded the best reaction yield.

Ultrasound assisted enzyme catalyzed degradation of Cetirizine dihydrochloride

Cetirizine dihydrochloride, a pharmaceutical drug of the class antihistamines is frequently detected in wastewater samples. In the present work, the degradation of Cetirizine dihydrochloride is carried out using a novel technique of laccase enzyme as a catalyst under the influence of ultrasound irradiation. Effect of various process parameters such as enzyme loading, temperature, power, duty cycle, frequency and speed of agitation has been studied along with identification of the degradation intermediates. The maximum degradation of 91% is achieved at optimized experimental parameters such as 0.02% enzyme loading (w/v), 50°C temperature, power input of 100W, 25kHz frequency and 50% duty cycle with agitation speed of 200rpm. It is observed that enzymatic degradation of Cetirizine dihydrochloride under the influence of ultrasound irradiation not only enhances the degradation but also reduces the time of degradation as compared to conventional enzymatic degradation technique.

Ultrasound-mediated synthesis of 4-substituted 1,4-dihydropyridine-3,5-dicarboxylates catalyzed by 1-carboxymethyl-3-methylimidazolium tetrafluoroborate under solvent free condition

4-Substituted 1,4-dihydropyridine-3,5-dicarboxylates (4) have been synthesized by the solvent-free reaction of aldehyde, methyl propiolate and ammonium carbonate catalyzed by ionic liquid 1-carboxymethyl-3-methylimidazolium tetrafluoroborate under ultrasonic irradiation. The effects of changes in the ultrasonic power, temperature, catalysts and reactants on the synthesis of 4-substituted 1,4-dihydropyridine-3,5-dicarboxylates (4) are discussed. With the optimized reaction conditions, various aldehydes were used to synthesize 1,4-dihydropyridines (4) under the influence of ultrasound irradiation. Compared with the conventional thermal methods, the remarkable advantages of this method are the simple experimental procedure, shorter reaction time (2–10min) and high yield of product (76–95%). Furthermore, the green catalytic system can be recycled specific times without significantly decreasing the yields and reaction rates.

A Convenient and Efficient Protocol for the Synthesis of HBIW Catalyzed by Silica Nanoparticles under Ultrasound Irradiation

2,4,6,8,10,12-Hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.05,9.03,11]dodecane (hexabenzylhexaazaisowurtzitane, HBIW) has been synthesized by the reaction of benzylamine and glyoxal (40% aqueous solution) in acetonitrile as a solvent catalyzed by silica nanoparticles (SiO2 NPs, ca. 42 nm) under ultrasound irradiation. The effects of solvent, catalyst, and ultrasonic power are discussed. With optimized reaction conditions, HBIW was synthesized under the influence of ultrasound irradiation. Compared with conventional methods, the remarkable advantages of this method are the simple experimental procedure, shorter reaction time, and high product yield.

Batch and fed-batch enzymatic hydrolysis of soybean oil under ultrasound irradiation

Abstract This work reports the hydrolysis of fatty acids from soybean oil using a commercial immobilized lipase (Lipozyme TL IM) under the influence of ultrasound irradiation. Batch and fed-batch experiments were performed at 65 °C, 10 wt% of enzyme concentration, oil to water molar ratio of 1:9, output irradiation power of 132 W, and 600 rpm agitation. Results show that ultrasound-assisted lipase-catalyzed hydrolysis of oils system might be a potential alternative route to conventional methods, as almost complete reaction yield was achieved for the fed-batch system, with relatively good results for the batch mode at mild irradiation power supply and temperature in a relatively short reaction time, 120 min. Besides, it is shown that the initial reaction rates are of hydrolysis are increased when ultrasound irradiation was applied into the reaction system.