Intensity Of Ultrasonic Irradiation Research Articles

Sono-hollow fiber membrane contactors: A new approach for CO2 separation by physical/chemical absorbents

Herein, the nano adsorbents of Fe3O4 and Fe3O4@SiO2–NH2 were first synthesized and then dispersed in distilled water as a base fluid for Carbon dioxide (CO2) separation from a gas stream using a polypropylene hollow fiber membrane contactor (PP HFMC) and the separation experiment was performed under non-ultrasonic/ultrasonic irradiation for the first time. The impacts of varying liquid and gas flow rates, nanoparticles (NPs) loading, absorbents viscosity, NPs stability, and ultrasonic irradiation intensity were evaluated on the performance of Fe3O4 and Fe3O4@SiO2–NH2 nanofluids in CO2 separation. According to the obtained results, Fe3O4@SiO2–NH2 nanofluid was considerably powerful compared to Fe3O4 nanofluid due to the advantage of chemical reaction with CO2. Furthermore, ultrasound irradiation effectively raised the CO2 absorption capacity of Fe3O4 and Fe3O4@SiO2–NH2 nanofluids up to 13.37 and 16.41%, respectively. Ultimately, at the best operational condition, the CO2 separation enhancement factors of 58.44 and 84.45% were achieved by Fe3O4@SiO2–NH2 nanofluid under non-ultrasonic irradiation and ultrasonic irradiation conditions.

ZnFe-Cl nanolayered double hydroxide as a novel catalyst for sonocatalytic degradation of an organic dye

ZnFe nanolayered double hydroxide (NLDH) with anions of Cl− in its interlayer space was synthesized using a facile co-precipitation method. The synthesized ZnFe-Cl NLDH was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), N2 adsorption/desorption, diffuse reflectance spectroscopy (DRS) and point of zero charge pH (pHpzc) analyses. In this research, the sonocatalytic activity of the as-prepared NLDH was investigated for removal of acid red 17 as model pollutant. The effects of the operating parameters including sonocatalyst concentration, pH, initial dye concentration, intensity of ultrasonic irradiation and the presence of radical scavengers and process enhancers were studied on the sonocatalytic degradation of acid red 17. The decreased decolorization efficiency in the presence of the radical scavengers confirmed that the free radicals play the basic roll in the degradation of acid red 17 molecules. In addition a probable mechanism for degradation of acid red 17 through the sonocatalytic process was proposed according to the identified intermediates detected using gas chromatography–mass (GC–MS) spectroscopy.

Evaluation of critical parameters for preparation of stable clove oil nanoemulsion

In this work, the effects of various factors, including the ultrasonic duty cycle and intensity of ultrasonic irradiation, ultrasonication and clove oil content in production of clove oil nanoemulsion were investigated. In preparation of nanoemulsion Tween® 80/Span® 80 as nonionic surfactants via ultrasonic emulsification method was used. The average droplets size of clove oil nanoemulsion decreased with an increase in duty cycle; whereas pulsed ultrasound with proper intervals was more efficient than continuous ultrasonication. In order to replace the use of organic solvent and increase the dispersity of active ingredient, suitable emulsifiers were used. The nanopesticides made by ultrasound at optimum formula conditions were defined at ultrasonication time of 300s, surfactants concentration of 5wt%, hydrophilic–lipophilic balance number of 9, duty cycle 0.75% and ultrasonic intensity 208W/cm2. The stability of droplets size of nanoemulsions for duration of 6months was evaluated. Stable nanoemulsion clove oil with 10wt% of clove oil content was formulated at optimum conditions with average droplets size around 43nm at the beginning and after 6months nanoemulsions re-sized and it was around 100nm. A stable nanoemulsion of clove oil in water with suitable droplets size as a nanopesticide was prepared.

Ultrasound-assisted regeneration of granular activated carbon saturated by 4-chlorophenol in batch-loop reactor

AbstractThe present work reports an investigation for examining the use of low-frequency ultrasound (20 kHz) as an inventive technique for the regeneration of granular activated carbon (GAC) saturated by 4-chlorophenol (4-CP) in batch-loop reactor. The effects of experimental conditions such as the amount of adsorbent (0.05–0.4 g), intensity of ultrasound irradiation (20–35%), temperature (25–55°C), flow rate (3–30 mL/min) and total volume of regenerating solution (200–300 mL), NaOH (0.01–0.1 N), ethyl alcohol (10–60%) and mixture of NaOH, and ethanol on the regeneration process were examined. The obtained results show that the amount of 4-CP desorption decreased with increasing the amount of adsorbent and intensity of ultrasonic irradiation. The desorption gradually increased with the increase in temperature and flow rate and total volume of regenerating solution. Using NaOH or/and ethyl alcohol as regenerating solutions causes an improvement in the desorption of 4-CP from GAC. The regeneration of spent ...

Effects of blending composition of tung oil and ultrasonic irradiation intensity on the biodiesel production

The beneficial use of tung oil in pre-blended oil for the production of biodiesel was studied at various blending compositions of tung, canola and palm oils (CBT, CBC and CBP). The effects of CBT, ultrasonic power (PWUS) and sample loading (VL) on the yield (YF) and the properties of acid value, iodine values (IV), kinematic viscosity (KV), density and cold filter plugging point (CFPP) were investigated. The pre-blending of tung oil with palm oil greatly decreases the CFPP of palm oil biodiesel, whereas the presence of canola and palm oils with tung oil reduces the IV and KV of tung oil biodiesel. For PWUS/VL = 0.92–2.08 W/mL, CBT can be as high as 60 wt.% with 30 wt.% CBC and 10 wt.% CBP to produce biodiesel with high YF and satisfactory qualities of the said properties.

ENHANCED HOMING OF MESENCHYMAL STEM CELLS TO THE ISCHAEMIC MYOCARDIUM BY ULTRASOUND-TARGETED MICROBUBBLE DESTRUCTION

ObjectivesThe transplantation of bone-marrow derived mesenchymal stem cells (MSCs) to ischaemic myocardium is considered to be a useful therapeutic approach to ischaemic heart disease, but the MSCs delivery efficacy still...

Ultrasonic Irradiation for Blue-Green Algae Bloom Control

A novel application of ultrasonic irradiation for rapid control of blue-green algae (BGA) bloom was investigated. Potassium iodide (KI) experiments demonstrated that frequency and input power are the major factors that affect the ultrasonic irradiation intensity. Short exposure (3 s) to ultrasonic irradiation (120 W input power, 28 kHz) effectively settled naturally growing BGA suspension. Electron microscopy reconfirmed that sedimentation was caused by the disruption and collapse of gas vacuoles after ultrasonic exposure. Moreover, even after 5 min of exposure to ultrasonic irradiation (1200 W input power, 28 kHz) the microcystin concentration in BGA suspensions did not increase. For the same input power (120 W), a lower frequency (28 kHz) was found to be more effective in decreasing the photosynthetic activity of BGA than a higher frequency (100 kHz). The sonicated cells did not proliferate when they were cultured in conditions that simulated the bottom of water bodies (i.e. with limited light (400 lx) or no light and non-aerated or aerated (1 l min−1)). Furthermore, ultrasonic irradiation did not only collapse gas vacuoles and precipitate BGA, but may have also inflicted damage on the photosynthetic system of the BGA.

Modification of polypropylene with maleic anhydride: Ultrasonic irradiation effects

The mechanochemical reaction of modificated of polypropylene (PP) with maleic anhydride (MAH) has been studied by ultrasonic irradiation as an energy source at 60°C. Through 23 factorial experimental design, three variables and their interactions were studied: the percentage of MAH, the percentage of benzoyl peroxide (BPO), and ultrasonic irradiation intensity (Watts). According to the results, an increase of wt % of MAH gave a negative effect in the grafting yield; in addition, this negative effect was observed in the interaction of MAH : BPO at a high range of wt %, this behavior is attributed to the homopolymerization of MAH at the experimental conditions employed. The higher positive effect onto the grafting yield was observed for the variable watts (ultrasonic irradiation intensity), even at low intensity. The better interaction of variables gave a MAH grafting degree of 4.65 wt % (93% yield). In addition, the effect of ultrasonic irradiation on the number-average molar mass (Mn), weight-average molar mass (Mw), and polydispersity index (Mw/Mn) was measured. It was observed that the Mw decreased 13.73% and the Mw/Mn also decreased by 11.98%. The o observed effect was attributed to the degradation mechanism induced by the ultrasound, which consists in the generation of macroradicals and their recombination. The product PP-g-MAH was characterized by infrared spectroscopy, also was used to prepare polypropylene–nylon-6 blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:45–52, 1998

Modification of polypropylene with maleic anhydride: Ultrasonic irradiation effects

The mechanochemical reaction of modificated of polypropylene (PP) with maleic anhydride (MAH) has been studied by ultrasonic irradiation as an energy source at 60°C. Through 23 factorial experimental design, three variables and their interactions were studied: the percentage of MAH, the percentage of benzoyl peroxide (BPO), and ultrasonic irradiation intensity (Watts). According to the results, an increase of wt % of MAH gave a negative effect in the grafting yield; in addition, this negative effect was observed in the interaction of MAH : BPO at a high range of wt %, this behavior is attributed to the homopolymerization of MAH at the experimental conditions employed. The higher positive effect onto the grafting yield was observed for the variable watts (ultrasonic irradiation intensity), even at low intensity. The better interaction of variables gave a MAH grafting degree of 4.65 wt % (93% yield). In addition, the effect of ultrasonic irradiation on the number-average molar mass (Mn), weight-average molar mass (Mw), and polydispersity index (Mw/Mn) was measured. It was observed that the Mw decreased 13.73% and the Mw/Mn also decreased by 11.98%. The o observed effect was attributed to the degradation mechanism induced by the ultrasound, which consists in the generation of macroradicals and their recombination. The product PP-g-MAH was characterized by infrared spectroscopy, also was used to prepare polypropylene–nylon-6 blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:45–52, 1998

Sonochemistry: from research laboratories to industrial plants

The problems of scaling up successful sonochemical reactions is addressed from the point of view of reaction conditions and equipment available both on the laboratory and large scale. The link between ultrasonic processing and chemical reactors is explored as a means of identifying possible equipment for industrial scale sonochemistry. The important dependence of product formation on the intensity of ultrasonic irradiation is explored.

Sonolysis of perhalomethane as studied by EPR and spin trapping

Intense ultrasonic waves have been reported to produce chemical changes by the phenomenon of cavitation (1-3). Although some sonochemically induced reactions proceed undoubtedly by an ionic mechanism (4-7), others most probably involve free radical intermediates (8, 9) although no direct evidence has been provided. We report our attempts to generate free radicals at room temperature in fluid solutions by ultrasonic exposure and their detection by EPR. We found that sonolysis of pure carbon tetrachloride or trichlorobromomethane generates free radicals which could be spin-trapped by 2-methyl-2nitrosopropane and identified. A Bransonic 12 ultrasonic cleaner (frequency, 50 kHz) was used as a generator of ultrasonic waves. The reaction mixture (3 ml) contained in a Pyrex test tube was held in the middle of the bath, and the vertical position of the tube was adjusted to maintain the same level of liquid inside the tube as outside. Particular care was taken to insure the reproducibility, by positioning the tube in the same place, keeping the water level and the temperature in the bath constant (23”C), etc. (10). The intensity of ultrasonic irradiation under these experimental conditions was monitored before each experiment by a calorimetric procedure which measures the amount of chlorine released in CC&-saturated water by ortho-tolidine reagent (II). Thus, a mixture of 3 ml water saturated with CCL, and 0.15 ml o&o-tolidine reagent (0.1% solution, Fisher Scientific Co.) was sonicated for 30 sec. The intensity of the yellow color was measured in a l-cm cell at 436 nm to be 0.8 IC_ 0.1 under our experimental conditions. When CCL or CCl,Br containing 2-methyl-2-nitrosopropane (1.5 mg/ml) was sonicated and subsequently analyzed by EPR, a spectrum composed of a triplet of ON = 6.7 G could be recorded (Fig. 1). This splitting characteristic of an acyl spin adduct (12) is attributed to the nitroxone I