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  • Investigations on Sonofragmentation of Hydroxyapatite Crystals as a function of Strontium Incorporation
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-17
    Nimmy Edwin, P. Wilson

    Hydroxyapatite (Ca10(PO4)6(OH)2, HA) is chemically similar to the mineral component of bones and hard tissues in mammals. Various cations can substitute calcium in the crystal structure of hydroxyapatite. Among them strontium triggers interest, because strontium incorporated hydroxyapatite increases the number of bone forming sites in addition to having good biocompatibilityIn the present investigation strontium substituted hydroxyapatite (SHA) in the compositions range 0, 10, 20, 50 and 100 mol% have been synthesized by precipitation method and subjected to ultrasonic treatment for different time intervals to gain insight on the role of ultrasound in modifying the morphology of SHA. This study reveals that the aspect ratio of SHA varied with the duration of ultrasonication. SHA samples subjected to 5 min ultrasound experienced an increase in aspect ratio. Further increase of ultrasonication time tends to decrease the aspect ratio invariably for all SHA samples indicating particle fragmentation. The extent of sonofragmentation as a function of percentage incorporation of strontium in HA lattice has been studied as a part of the present investigation. This study indicated that strain in the HA lattice has correlation with strontium incorporation, leading to varied extent of sonofragmentation. Also, the investigation suggested that 100% substitution of calcium sites by strontium leads to a relatively lesser strain and hence poor fragmentation. To the best of our knowledge the report on sonofragmentation of HA crystallites as a function of strontium incorporation is first of its kind in the literature.

    更新日期:2018-09-18
  • Ultrasound-assisted preparation of flaxseed oil nanoemulsions coated with alginate-whey protein for targeted delivery of omega-3 fatty acids into the lower sections of gastrointestinal tract to enrich broiler meat
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-17
    Fatemeh Abbasi, Firooz Samadi, Seid Mahdi Jafari, Sanaz Ramezanpour, Mahmoud Shams Shargh

    Flaxseed oil is one of the richest sources of omega-3 fatty acids. However, the susceptibility of omega-3 fatty acids to oxidation and also lack of the convenient method to deliver these invaluable compounds into the lower sections of gastrointestinal tract (GIT) are still unknown. The objective of the current study was to establish a method for omega-3 fatty acids targeted delivery into the lower sections of GIT to enrich broiler meat. An in vitro study was performed to use ultrasound to produce oil-in-water nanoemulsions of flaxseed oil stabilized by different wall materials in order to controlled release of omega-3 fatty acids in GIT. The fabricated nanoemulsions were assessed in terms of particle size distribution, zeta-potential, encapsulation efficiency, field emission scanning electron microscopy (FESEM), and in vitro gastric and intestinal digestions. Results indicated that the nanoemulsions coated by a combination of whey protein-sodium alginate (WP/SA) had a relatively uniform distribution and all particles distributed in less than 1000 nm. The values of zeta-potential for nanoemulsions stabilized by whey protein (WP), sodium alginate (SA) and WP/SA were -31.4, -29.3 and -45.5 mV, respectively. The wall combination of WP/SA showed the best encapsulation efficiency followed by WP. The FESEM results indicated spherical and non-aggregated structures for three types of nanoemulsions. The nanoemulsions stabilized by WP/SA showed a high resistance to in vitro gastric digestion but a relatively rapid release during intestinal digestion. An in vivo study was conducted to enrich broiler meat with α-linolenic acid (ALA) omega-3 fatty acid, using the best wall material from the in vitro study. In total, 300 one-day-old broilers (Ross, 308) were assigned into 5 experimental treatments including: basal diet (BD), basal diet plus flaxseed oil (BD+FO, 1mL/Kg body weight), basal diet plus ultrasonic flaxseed oil nanoemulsion stabilized by WP/SA (BD+FON, 1mL/Kg body weight), basal diet plus flaxseed oil and vitamin E (BD+FO+E, 1mL/Kg body weight and 200 mg/Kg diet vitamin E) and basal diet plus ultrasonic flaxseed oil nanoemulsion stabilized by WP/SA and vitamin E (BD+FON+E, 1mL/Kg body weight of nanoemulsion and 200 mg/Kg diet vitamin E). Each experimental treatment included of 4 replicates in a completely randomized design. Results showed a better feed conversion ratio (FCR) in birds treated with dietary treatments compared with those received basal diet. A greater incorporation of ALA and total poly unsaturated fatty acids (PUFA) omega-3 were observed in thigh and breast meat of birds fed by ultrasonic flaxseed oil nanoemulsions. In comparison to birds fed BD, a favourably lower PUFA omega-6/omega-3 ratio was observed in birds received nanoemulsions of flaxseed oil. In general, the current study showed that using ultrasound to produce nanoemulsion stabilized by WP/SA has potential to protect ALA of flaxseed oil from gastric digestion and could be used as delivery carrier of ALA omega-3 fatty acid to the posterior sections of chicken gastrointestinal tract. Moreover, ultrasonic fabrication of nanoemusion has potential to enrich broiler meat by ALA omega-3 fatty acid.

    更新日期:2018-09-18
  • The sonochemical synthesis of vertically aligned ZnO nanorods and their UV photodetection properties: Effect of ZnO buffer layers
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-17
    Nama A. Hammed, Azlan Abdul Aziz, Adamu Ibrahim Usman, M.A. Qaeed

    Vertically aligned Zinc oxide nanorods (ZnO NRs) were successfully synthesized in this study using the sonochemical method to improve the intrinsic properties of UV photodetector (PD). Three different thin films: Ti/Zn, Ti/ZnO, and Ti/ZnO/Zn, with the thicknesses of 10 nm/55 nm, 10 nm/85 nm, and 10 nm/85 nm/55 nm respectively, were deposited on glass substrates using the RF-sputtering technique. The synthesized ZnO NRs were investigated using XRD, FESEM and Raman spectroscopy to determine the effect of Zn and ZnO as seed layers, and ZnO as a buffer layer on the surface morphology, crystal structure, optical properties of ZnO NRs. The ZnO NRs grown on Zn/Ti, ZnO/Ti, and Zn/ZnO/Ti are characterized by hexagonal crystal structure with preferential growth in the c-axis direction. The ZnO NRs grown on Zn/ZnO/Ti displayed the highest density, uniform size distribution, vertically aligned rods and aspect ratio. The UV device fabricated from the ZnO NRs grown on Zn /ZnO/Ti also showed the highest photocurrent (360 µA) and responsivity of (878 mA/W). ZnO NRs grown on Zn/ZnO/Ti were also observed to be highly stable and exhibited a relatively rapid response and recovery times for different time intervals when exposed to the UV light of 365 nm wavelength. Thus, the inclusion of the ZnO as a buffer layer (Zn as a seed layer/ZnO as buffer layer/Ti as a buffer layer) improve the properties of the ZnO NRs. In addition, the current gain of ZnO NRs grown on Zn (55 nm)/ZnO (85 nm)/Ti (10 nm) - based ultraviolet (UV) photodetector (PD) is about two times higher than that of conventional Zn (55 nm)/ZnO (85 nm)/Ti (10 nm) thin-films UV PD, which is due to the higher surface-to-volume ratio of ZnO nanorods (NRs) compared with their thin films. This study confirms the possibility of sonochemically fabricating vertically aligned ZnO nanorods as well as its applicability as a viable UV photodetector.

    更新日期:2018-09-18
  • Effects of the ultrasound-assisted pretreatments using borax and sodium hydroxide on the physicochemical properties of Chinese fir
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-17
    Zhenyu Wang, Lijie Qu, Jing Qian, Zhengbin He, Songlin Yi

    This work investigated the physicochemical properties of Chinese fir after ultrasound-assisted pretreatments with borax and sodium hydroxide additives in an aqueous solution. TGA, FTIR, and XRD were used to analyze the thermal degradation processes, changes in chemical structures, and crystallinity of the treated samples, respectively. Additionally, the release of volatiles from wood pyrolysis was measured on-line by the TG-FTIR apparatus. In thermal analysis, all samples showed main degradation stages at 220-500 °C, and alkaline compounds could efficiently shift the process to lower temperatures with lower maximum weight loss rate (MWLR) and more residues. From TG-FTIR, it was observed that CO2 was the primary gas product from pyrolysis in the alkaline-treated samples, while there were more carbonyl compounds released in the control and deionized water groups. Due to the destruction and removal of hemicellulose and lignin after alkaline treatments, the related peaks changed greatly. Changes in the ester groups caused by saponification also accounted for one of the most significant differences between samples. Moreover, except for the deionized water group without sonication, the crystallinity of the samples increased from 6.34% to 11.29%. Overall, comparing the samples treated with or without ultrasound, the results showed that the ultrasound treatment did influence the samples’ physicochemical properties, and its’ effects varied by the basicity of the solution. This in-depth investigation offers a better understanding of ultrasound-assisted and alkaline pretreatments of wood materials.

    更新日期:2018-09-18
  • Urea Functionalization of Ultrasound-Treated Biochar: A Feasible Strategy for Enhancing Heavy Metal Adsorption Capacity
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-17
    Baharak Sajjadi, James William Broome, Wei Yin Chen, Daniell L. Mattern, Nosa O. Egiebor, Nathan Hammer, Cameron L. Smith
    更新日期:2018-09-17
  • Ultrasound and meat quality: A Review
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-17
    Alma Delia Alarcon-Rojo, Luis Manuel Carrillo-Lopez, Raul Reyes-Villagrana, Mariana Huerta-Jiménez, Ivan Adrian Garcia-Galicia

    High intensity ultrasound (HIU) offers an alternative to traditional methods of food preservation, and is regarded as a green and promising emerging technology. Ultrasound generates acoustic cavitation in a liquid medium, developing physical forces that are considered the main mechanism responsible for changes in exposed materials. In meat, ultrasound has been successfully used to improve processes such as mass transfer and marination, tenderization of meat and inactivation of microorganisms. It is also an alternative to traditional meat ageing methods for improving the quality properties of meat. Moreover, the combination of ultrasonic energy with a sanitizing agent can improve the effect of microbial reduction in foods. This review describes recent potential applications of ultrasound in meat systems, as well as physical and chemical effects of ultrasound treatment on the conservation and modification of processed meat foods. Finally, the ultrasound application parameters must be deep explored and established before the method can be scaled to industrial levels.

    更新日期:2018-09-17
  • Sono-nano chemistry: A new era of synthesising polyhydroxylated carbon nanomaterials with hydroxyl groups and their industrial aspects
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-14
    Sadia Afreen, Kasturi Muthoosamy, Sivakumar Manickam

    The main objective of this review is to derive the salient features of previously developed ultrasound-assisted methods for hydroxylating graphene and Buckminsterfullerene (C60). The pros and cons associated to ultrasound-assisted synthesis of hydroxy-carbon nanomaterials in designing the strategical methods for the industrial bulk production are also discussed. A guideline on the statistical methods has also been considered to further provide the scopes towards the application of the previously reported methods. Irrespective of many useful methods that have been developed in order to functionalize C60 and graphene by diverse oxygenated functional groups e.g. epoxide, hydroxyl, carboxyl as well as metal/metal oxide via a combination of organic chemistry and sonochemistry, there is no report dealing exclusively on the application of ultrasonic cavitation particularly to synthesising polyhydroxylated carbon nanomaterials. On this context, this review emphasizes in investigating the critical aspects of sono-nanochemistry and the statistical approaches to optimize the variables in the sonochemical process towards a large-scale synthesis of polyhydroxylated graphene and C60.

    更新日期:2018-09-14
  • The influence of intense ultrasound applied during pressing on the optical and cathodoluminescent properties of conventionally sintered YSZ ceramics
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-12
    O.L. Khasanov, E.S. Dvilis, E.F. Polisadova, S.A. Stepanov, D.T. Valiev, V.D. Paygin, D.V. Dudina

    The aim of the present work was to investigate the effect of the ultrasonic treatment on the optical and cathodoluminescent properties of translucent ZrO2-8 mol.% Y2O3 (YSZ) ceramics obtained by conventional sintering of the pressed compacts. Treatment by intense ultrasound during dry pressing of the YSZ nanopowder leads to an increase in the relative density, a decrease in the pore size and an increase in the grain size of the sintered ceramics. It was shown that when the ultrasonic treatment is applied, the optical absorption cutoff wavelength of the sintered material is shifted to longer wavelengths, while the optical density of the material increases over the whole measurement spectrum. Samples subjected to ultrasonic treatment during pressing show higher intensity of luminescence than those obtained without the use of ultrasound, the shape of the luminescence spectra remaining unchanged. A correlation was obtained between the integral intensity of cathodoluminescence and the vacancy concentration in the sintered YSZ.

    更新日期:2018-09-13
  • Sonochemical degradation of antibiotics from representative classes- Considerations on structural effects, initial transformation products, antimicrobial activity and matrix
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-11
    Efraím A. Serna-Galvis, Diana Montoya-Rodríguez, Laura Isaza-Pineda, María Ibáñez, Félix Hernández, Alejandro Moncayo-Lasso, Ricardo A. Torres-Palma

    In this work, the sonochemical treatment (at 354 kHz and 200W) of six relevant antibiotics belonging to fluoroquinolones (ciprofloxacin and norfloxacin), penicillins (oxacillin and cloxacillin) and cephalosporins (cephalexin and cephadroxyl) classes was evaluated. Firstly, the ability of the process to eliminate them was tested, showing that sonodegradation of these antibiotics is strongly chemical structure-dependent. Thus, correlations among initial degradation rate of pollutants (Rd), solubility in water (Sw), water-octanol partition coefficient (Log P) and topological polar surface area (TPSA) were tested. Rd exhibited a good correlation with Log P (i.e., the hydrophobicity degree of antibiotics). The considered penicillins had the fastest elimination and from the constitutional analysis using Lemke method was clear that the functional groups arrangement on these antibiotics made them highly hydrophobics. The penicillins were degraded closer at cavitation bubble than the fluoroquinolones or cephalosporins. The investigation of degradation products showed that sonogenerated hydroxyl radical primary attacked the β-lactam ring of cloxacillin and cephalexin, whereas on norfloxacin induced a decarboxylation. On the other hand, the evolution of antimicrobial activity was also followed. It was evidenced the process capacity to remove antimicrobial activity from treated solutions, which was associated to the transformations of functional groups on antibiotics with important role for interaction with bacteria. Additionally, degradation of antibiotics having the highest (the most hydrophobic, i.e., cloxacillin) and lowest (the most hydrophilic, i.e., cephadroxyl) Rd, was performed in synthetic matrices (hospital wastewater and seawater). Ultrasound degraded both antibiotics; for cloxacillin in such waters higher eliminations than in distilled water were observed (probably due to a salting-out effect exerted by matrix components). Meanwhile, for cephadroxyl a moderate inhibition of degradation in hospital wastewater and seawater respect to distilled water was found, this was related to competition by hydroxyl radical of the other substances in the matrices. These results show the quite selectivity of high frequency ultrasound to eliminate antibiotics form different classes even in complex matrices.

    更新日期:2018-09-11
  • Effect of different electrolytes and deposition time on the supercapacitor properties of nanoflake-like Co(OH)2 electrodes
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-07
    N.C. Maile, S.K. Shinde, R.R. Koli, A.V. Fulari, D.Y. Kim, V.J. Fulari

    The effect of ultrasonic treatment and deposition time on nanoflake-like Co(OH)2 thin films were prepared using the potentiostatic mode of electrodeposition method on stainless steel substrates by a nitrate reduction reaction. After ultrasonic treatment, we used stainless steel substrates for deposition of the nanoflakes like Co(OH)2 thin films. The effect of deposition times and electrolytes on different physico-chemical properties of Co(OH)2 was investigated in detail, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and electrochemical testing. After ultrasonic treatment Co(OH)2 thin films had devolvement of the uniform and interconnected formation of nanoflakes nanostructures. Supercapacitor performance of the Co(OH)2 electrodes suggest that, specific capacitance are depends on the surface morphology, and Co(NO3)2 electrodes after ultrasonic treatment exhibited higher performance than without ultrasonication. The maximum specific capacitance of the 30 min. deposited Co(OH)2 nanoflakes exceeded 276 Fg−1 in 0.5M KOH electrolyte at 5 mVs-1 scan rate.

    更新日期:2018-09-07
  • Enhancing the cavitation erosion resistance of D8m-Ta5Si3 nanocrystalline coatings through Al alloying
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-05
    Jiang Xu, Wei Liu, Shuyun Jiang, Paul Munroe, Zong-Han Xie

    To investigate the effects of Al alloying on the erosion-corrosion resistance of β-Ta5Si3, both a β-Ta5Si3 coating and an Al-alloyed β-Ta5(Si0.83Al0.17)3 coating were synthesized on a 316 substrate by the double cathode glow discharge technique. The phase constitution, composition and microstructure of the two coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The two coatings were composed of nearly rounded D8m-β-Ta5Si3 grains with an average size of ∼4 nm, and after the addition of Al, the preferred growth orientation for the β-Ta5Si3 coating changed from (400) to (002). The hardness, elastic modulus and contact damage resistance of the coatings were measured using a nanoindentation tester. The results showed that Al alloying improved the contact damage resistance of β-Ta5Si3 with only a slight decrease in hardness. The erosion-corrosion behavior of the two coatings was performed in a 3.5 wt.% NaCl solution containing a 12 wt.% concentration of silica sand under two phase slurry flow condition and in a 3.5 wt.% NaCl solution under ultrasonic cavitation erosion conditions. This revealed that the Al alloyed β-Ta5Si3 has a higher resistance to both erosion-corrosion and ultrasonic cavitation erosion as compared to the binary β-Ta5Si3 coating.

    更新日期:2018-09-05
  • Ultrasound assisted synthesis of Mg-Mn-Zr impregnated activated carbon for effective fluoride adsorption from water
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-05
    Aditi Mullick, Sudarsan Neogi

    High fluoride content in the natural water sources is a serious matter of concern and adsorption is recommended as one of the most convenient, affordable and widely applied defluorination technologies. In this study, a novel composite was synthesized by impregnating magnesium (Mg), manganese (Mn) and zirconium (Zr) on powdered activated carbon (AC) for effective fluoride adsorption and the synthesis was made using sonochemical method. The characterization of the prepared adsorbent AC-Mg-Mn-Zr along with individual metal composites AC-Zr, AC-Mg and AC-Mn were done by SEM, EDX, FTIR, XRD and BET analysis to understand the major functional bonds, and changes in surface chemistry after adsorption. The mechanism of the process was discussed through major reactions involved for individual metals. Due to high point of zero charge (pHPZC=11.9), the adsorbent was able to remove more than 96% of fluoride consistently with only 1 g/L of optimum adsorbent dosage for a wide pH range (2 to 10). The maximum adsorption capacity obtained was 26.27 mg/g within an equilibrium time of 3 h. More than 96% energy saving was achieved in the sonochemical synthesis route compared to conventional precipitation method of synthesis.

    更新日期:2018-09-05
  • Effects of synergetic ultrasound on the Sc yield and primary Al3Sc in the Al-Sc alloy prepared by the molten salts electrolysis
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-05
    Xuan Liu, Zhichao Guo, Jilai Xue, Cheng Zhang

    In this work, ultrasound has been employed to help prepare Al-Sc alloys using the molten salt electrolysis. The effects of synergetic ultrasound on the Sc content and primary Al3Sc particles of Al-Sc alloys are specifically investigated. Ultrasound can strongly promote the Sc content of the electrolytic Al-Sc alloy and transform the large Al3Sc phase clusters into fine cubic particles. Meanwhile, it also homogenizes the distribution of Al3Sc phase. The Sc content increases by 74.4 % up to 1.43 wt.% when applying ultrasound during both electrolysis and solidification process. It also transforms the molten salts/liquid Al interface by enhancing the wettability. The huge primary Al3Sc phase clusters transform into fine cubic particles by ultrasound. The average particle size reduces from 77 ± 36 μm down to 21 ± 8 μm. The concerned mechanism have been discussed in detail.

    更新日期:2018-09-05
  • Treatment of petroleum oil spill sludge using the combined ultrasound and Fenton oxidation process
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-05
    Krishnasamy Sivagami, Deeksha Anand, Govindaraj Divyapriya, Indumathi Nambi

    In this paper, advanced oxidation process (AOP) combining ultrasound (US) and Fenton’s process was proposed for the treatment of total petroleum hydrocarbons present in oil spill sludge. The effect of several parameters like pH, ultrasonic power, weight ratio of hydrogen peroxide to iron [H2O2/Fe2+], Fenton reagent dosage, addition of salts and contact time were analyzed for the reduction of Petroleum Hydrocarbons (PHCs) in terms of hydrocarbon fractions (nC7−C10, nC11-C20). Chemical characterization of oil spill sludge was analysed by gas chromatography- mass spectrum (GC-MS) Elemental analyser, Fourier Transform Infra Red (FT-IR) Analyser and particle size analyser. Experiments were conducted for identifying the wide range of hydrocarbons fractions (nC7−C10, nC11─C20 and nC21─C30). Results shown that maximum solubilisation and PHC removal rate of up to 84.25% could be achieved at a pH of 3.0, sludge/water ratio of 1:100, ultrasonic power of 100 W with 40 - 50 % ultrasonic amplitude, a H2O2/Fe2+ weight ratio of 10:1, and an ultrasonic treatment time of 10 minutes. The lower and medium fractions (nC7−C10, nC11─C20) were amenable to degradation due to ultrasound treatment compared to the heavier carbon fraction (nC21─C30). The study concludes that the combined sono-Fenton (SF) process significantly enhanced the degradation of oil spill sludge as compared to ultrasound treatment and Fenton oxidation alone. The enhanced solubilisation achieved by US alone is highly beneficial when we couple this with biodegradation which will be greatly facilitated by the enhanced solubility.

    更新日期:2018-09-05
  • Kinetic model for sonolytic degradation of non-volatile surfactants: perfluoroalkyl substances
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-05
    Takshak Shende, Gangadhar Andaluri, Rominder P.S. Suri
    更新日期:2018-09-05
  • Microwave Synthesized Complex Concentrated Alloy Coatings: Plausible Solution to Cavitation Induced Erosion -Corrosion
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-03
    Rakesh.B. Nair, H.S. Arora, H.S. Grewal

    Surface phenomenon such as cavitation erosion-corrosion limits the working life and durability of the fluid machines through significantly altering the efficiency. Surface modification is an apparent and economical route for improving the sustainability of these components. Recently developed complex concentrated alloys (CCAs) or high entropy alloys (HEAs) possess exceptional properties owing to high configurational entropy. We developed CCA coatings on the stainless steel using a facial and effective microwave processing technique. The effect of Al molar fraction in AlxCoCrFeNi (x = 0.1 to 3) CCAs on ultrasonic cavitation erosion-corrosion was investigated in 3.5% NaCl solution. For comparison, cavitation erosion and electrochemical corrosion behavior of the pre- and post- tested samples was also performed. Detailed microstructure and mechanical characterization of the developed coatings were also preformed using different analytical techniques. The equimolar CCA coating showed apical degradation resistance under both pure erosion and erosion-corrosion conditions. The observed behavior is attributed to high strain hardening, optimal hardness, fracture toughness, and utmost stability of the passive layer. The phenomenal conjugation of these properties was associated with highest configurational entropy for equimolar composition resulting in sluggish diffusion, and severe lattice straining. Compared to pits, striations and cracks characterizing the morphology of the degraded stainless steel, the equimolar and Al0.1CoCrFeNi CCAs showed TTS (tearing topograph surface) as the dominant failure mode characterized by presence of microplastic deformation. The degradation of the Al3CoCrFeNi CCA occurred mainly through brittle failure mode. The difference in failure mechanism are related with the mechanical properties and underlying microstructure.

    更新日期:2018-09-04
  • Sonochemical synthesis of Molybdenum oxide (MoO3) microspheres anchored graphitic carbon nitride (g-C3N4) ultrathin sheets for enhanced electrochemical sensing of Furazolidone
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-03
    Paramasivam Balasubramanian, Muthaiah Annalakshmi, Shen-Ming Chen, Tse-Wei Chen

    Present strategy introduce the sonochemical synthesis of molybdenum oxide (MoO3) microspheres anchored graphitic carbon nitride (g-C3N4) ultrathin sheets as a novel electrocatalyst for the detection of Furazolidone (FU). TEM results revealed that MoO3 are microspheres with an average size of 2 µM and the g-C3N4 seems like ultrathin sheets. Owing to their peculiar morphological structure, g-C3N4/MoO3 composite modified electrode provided an enriched electroactive surface area (0.3788 cm2) and higher heterogeneous electron transfer kinetics (Koeff =4.91×10-2 cm s-1) than the other controlled electrodes. It is obviously observed from the voltammetric studies that the proposed sensor based on g-C3N4/MoO3 composite can significantly improve the electrocatalytic efficiency towards the sensing of FU. Due to the excellent synergic effect of g-C3N4/MoO3 composite, can detect the ultra-level FU with a limit of detection of 1.4 nM and a broad dynamic range of 0.01-228 µM, which surpassed the many previously reported FU sensors. Hence, the proposed sensor was successfully applied to sensing the FU in human blood serum, urine and pharmaceutical samples, gained an agreeable recoveries.

    更新日期:2018-09-04
  • Oxygen-rich bismuth oxychloride Bi12O17Cl2 materials: construction, characterization, and sonocatalytic degradation performance
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-03
    Fei Chang, Feiyan Wu, Wenjing Yan, Mingzhi Jiao, Jiaojiao Zheng, Baoqing Deng, Xuefeng Hu

    In this study, a series of oxygen-rich bismuth oxychloride Bi12O17Cl2 samples were prepared at different calcination temperatures and characterized by X-ray diffraction patterns, UV-Vis diffuse reflectance spectra, scanning electron microscope, X-ray energy dispersion spectroscope, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The calcination temperature greatly affected microstructures and band structures of as-prepared samples, further influencing sonocatalytic degradation efficiencies over dye Rhodamine B. Some dependant factors such as ultrasonic power, catalyst dosage, pH value, initial concentration of Rhodamine B, and reaction temperature were systematically investigated and the robust sample Bi12O17Cl2-550 with a favourable microstructure and band structure provided the best sonocatalytic removal efficiency around 90% at the optimal condition. Based upon reactive species entrapping and hydroxyl radical detection experiments, a primary sonocatalysis mechanism was eventually speculated.

    更新日期:2018-09-04
  • Fine structure, crystalline and physicochemical properties of waxy corn starch treated by ultrasound irradiation
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-01
    Qing-Yu Yang, Xuan-Xuan Lu, Yong-Zhi Chen, Zhi-Gang Luo, Zhi-Gang Xiao

    As a simple and effective physical method, ultrasound irradiation has been used to modify starch. Native waxy corn starch was treated by ultrasound irradiation at 100 and 400 W in this study. Compared with native waxy corn starch, lower proportion of B1, B2, and B3, higher proportion of A chain were observed in ultrasonicated waxy corn starch. 1H NMR combined with HPSEC-MALLS-RI data showed that lower degree of branching was observed in ultrasonicated waxy corn starch, and α-1,4 glycosidic linkages were more stable than α-1,6 glycosidic linkages in waxy corn starches. 13C NMR data indicated that the content of double helices was decreased, and single helix and amorphous components were increased after ultrasound irradiation. The A-type crystal structure was scarcely affected according to X-ray diffraction (XRD) analysis. The granule surface of ultrasonicated waxy corn starch became notch and rough fragment, and lower particle diameter was observed in ultrasonicated waxy corn starch. These results demonstrated that ultrasound irradiation affected chain length distribution, double helices, single helices and amorphous state, especially α-1,4 glycosidic linkages and α-1,6 glycosidic linkages, of waxy corn starch.

    更新日期:2018-09-03
  • Effects of high-intensity ultrasound process parameters on the phenolic compounds recovery from araticum peel
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-09-01
    Henrique S. Arruda, Eric Keven Silva, Gustavo A. Pereira, Célio Fernando F. Angolini, Marcos N. Eberlin, M. Angela A. Meireles, Glaucia M. Pastore

    In this work, we investigated the effects of the nominal ultrasonic power (160-640 W) and process time (0.5-5.0 min) on the phenolic compounds recovery and antioxidant activity from araticum peel. The individual and synergistic effects of the process variables on the phenolic recovery were estimated using a full factorial experimental design. Operating at high nominal ultrasonic powers was possible to obtain high phenolic yields and antioxidant activities at short process times (≤ 5 min). The HPLC-ESI-QTOF-MS/MS analysis revealed that the araticum peel sample possessed 142 phytochemicals, 123 of which had not been reported in literature for this raw material yet. The most abundant phenolic compounds recovered were epicatechin, rutin, chlorogenic acid, catechin and ferulic acid. Thus, high-intensity ultrasound technology proved to be a simple, efficient, fast and low environmental impact method for obtaining phenolic compounds from araticum peel. In addition, araticum peel showed to be a promising source bioactive natural phenolics for further applications in the food, nutraceutical, cosmetic and pharmaceutical industries.

    更新日期:2018-09-03
  • Effect of Ultrasound on Dissolution of Al in Sn
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-30
    Yun Liu, Weiyuan Yu, Yingzong Liu

    This study investigated the dissolution behavior of the aluminum substrate in molten tin at 523 K, 573 K, and 623 K with and without applied ultrasonic vibration (USV) respectively. In order to reveal the mechanism of accelerated dissolution by USV, the ultrasonic pressure distribution in the molten pool and the cavitation thermal effect were simulated by finite element analysis. Furthermore, the microstructures after the dissolution were observed. The results showed USV greatly accelerated the dissolution rate (by 21–27 times) at the interface, where an uneven ultrasonic pressure distribution in the molten pool caused inhomogeneous dissolution. The amount of Al dissolved in Sn at a particular temperature after 5 s of USV was equivalent to a holding time of 30 min without USV. The simulation results showed that the cavitation-thermal effect caused by USV increased the temperature (up to the melting point of Al) at the interfacial micro-region. It is evident that the combined effect of cavitation-thermal and ultrasonic streaming caused by USV increase the dissolution rate.

    更新日期:2018-08-31
  • Effects of high intensity ultrasound on disaggregation of a macromolecular procyanidin-rich fraction from Vitis vinifera L. seed extract and evaluation of its antioxidant activity
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-31
    Ana Muñoz-Labrador, Marin Prodanov, Mar Villamiel

    The impact of high intensity ultrasound (US, 45 and 20 kHz) on a purified macromolecular fraction (more than 85% of polymeric procyanidins) from grape seed extract was investigated. Matrix-Assisted Laser Desorption/Ionisation (MALDI TOF), Reverse Phase High Performance Liquid Chromatography (RP-HPLC) and Fourier-transform infrared spectroscopy (FTIR) revealed a modification in the chemical structure of these macromolecules treated by US and, particularly, bath US produced a considerable increase of up to 49, 41 and 35%, respectively, of catechins and oligomeric and polymeric procyanidin contents of the treated purified fraction. Bath US also produced, an important increase in the number of procyanidins with higher molecular mass (up to decamers) and an overall increase in the mass signal intensities in most of the detected B-type procyanidin series, as well as an important increase of the antioxidant activity of the macromolecular fraction of procyanidins. These results could be ascribed to a certain disaggregation of procyanidins linked to other biopolymers, such as proteins and/or polysaccharides, indicating that US is an efficient technology to modify the chemical structure and hence the bioactivity of tannins.

    更新日期:2018-08-31
  • Fast ultrasound-assisted synthesis of highly crystalline MIL-88A particles and their application as ethylene adsorbents
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-27
    Juan Amaro-Gahete, Rafael Klee, Dolores Esquivel, José Rafael Ruiz, César Jiménez-Sanchidrián, Francisco José Romero-Salguero

    Highly crystalline MIL-88A particles have been successfully synthesized via fast ultrasound-assisted processes. The influence of the sonication generator and synthesis time on the structure, crystallinity, morphology and surface area of the materials were studied in detail. Under this modified ultrasonic method, X-ray diffraction patterns of MIL-88A particles showed highly crystalline structures in contrast to those reported in literature. Significant differences on surface areas and microporosity were appreciated under ultrasound conditions employed. Specific surface areas in the range between 179 – 359 m2 g-1 were obtained. That material synthesized under ultrasound batch conditions during 1 h had the highest surface area and microporous character. Different particle sizes and morphologies were obtained depending on the synthesis procedure. In general, probe sonicators led to smaller particle sizes. Moreover, a comparative study of the ethylene adsorption of the MIL-88A particles and several common MOFs in the ethylene adsorption was investigated. The results suggest that the modified ultrasound-assisted procedure for the synthesis of MIL-88A is effective to obtain highly crystalline particles, which are very efficient to adsorb ethylene molecules.

    更新日期:2018-08-27
  • Characterization of heat-stable whey protein: Impact of ultrasound on rheological, thermal, structural and morphological properties
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-27
    Anju Boora Khatkar, Amarjeet Kaur, Sunil Kumar Khatkar, Nitin Mehta
    更新日期:2018-08-27
  • Numerical investigation of the effect of dual frequency sonication on stable bubble dynamics
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-24
    Kaouther Kerboua, Oualid Hamdaoui

    A computational study aiming to simulate an oxygen single acoustic bubble oscillation under a dual-frequency sonication was presented in this paper. The non-linear response of the bubble to the superposition of two fields of ultrasonic waves was investigated through dynamics parameters, collapse ratios and average velocities. The main goal of this analyze is to link the properties of the wave resulting from the dual-frequency excitation to the dynamics behavior of the bubble. The obtained results prove that, in contrast with the mono-frequency, coupling a wave to lower frequencies enhances the collapse duration and raises the compression ratio in the case of 35 kHz, while associating any of the studied waves to a higher frequency elevates the number of bubble oscillations during a time interval as compared to mono-frequency. The total sonochemical production has been investigated in accordance with the dynamics results, as well as the proportions of the three predominant free radicals, that show a dependency on the value of the basic frequency.

    更新日期:2018-08-26
  • A novel composite system composed of zirconia and LDHs film grown on plasma electrolysis coating: Toward a stable smart coating
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-22
    Mosab Kaseem, Young Gun Ko

    A novel composite system composed of zirconia and double hydroxide layers (LDHs) was successfully fabricated on the plasma electrolysis (PE) coating. For this aim, the molybdate-loaded LDHs film grown on the PE film of aluminum alloy was modified additionally by zirconia nanoparticles via a facile dip-coating method. The MoO42- anions which were obtained by anion exchange process from the precursor CeMgAl-LDH film, led to decrease the distance between the flakes of LDHs film where a flower-like structure was successfully developed. Moreover, the inclusion of zirconia helped to decrease the size of pores present in the LDHs films. Accordingly, a superior smart protective film was obtained due to the possible synergetic effects between the MoO42- and Ce3+ ions released from LDHs film as well as the high chemical stability of zirconia. The LDHs film modified by zirconia can be regarded as a stable smart coating, meaning that it has the ability to control the release of corrosion inhibitors and providing an excellent long-term electrochemical performance as well.

    更新日期:2018-08-22
  • Synthesis of poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) with low polydispersity using ultrasonic irradiation
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-21
    Masaki Kubo, Takuya Sone, Masahiro Ohata, Takao Tsukada

    Poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) having low polydispersity was synthesized in mixed solvent of ethanol and water using ultrasonic irradiation without any chemical polymerization initiator. The effects of the volume fraction of ethanol in the solvent, the molar ratio of two monomers, the monomer concentration and the ultrasonic power intensity on the time courses of the conversion to the polymer, the number average molecular weight, and the polydispersity of synthesized polymer were investigated in order to determine the optimal conditions to synthesize the copolymers with a narrow molecular weight distribution (i.e. low polydispersity). The optimum volume fraction of ethanol in the solvent was 60 vol% to synthesize the copolymers with a low polydispersity. A higher ultrasonic power intensity resulted in a faster polymerization rate and a lower number average molecular weight. The polydispersity was less than 1.5 for all ultrasonic power intensities up to 450 W/dm3 applied in this work. A higher monomer concentration gave a faster polymerization rate and a higher number average molecular weight. The polydispersity was less than 1.5 when the monomer concentration was lower than 0.4 mol/dm3. A higher molar ratio of N-isopropylacrylamide resulted in a higher polymerization rate and a lower number average molecular weight. The copolymers with polydispersity less than 1.5 can be obtained regardless of the molar ratio of N-isopropylacrylamide. The copolymers synthesized by the ultrasonic polymerization method had a high temperature responsibility.

    更新日期:2018-08-21
  • Effects of slit divergent ultrasound and enzymatic treatment on the structure and antioxidant activity of arrowhead protein
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-17
    Chaoting Wen, Jixian Zhang, Jie Zhou, Yuqing Duan, Haihui Zhang, Haile Ma

    The arrowhead has attracted great research interest for their potential applications in pharmacy, food and biomedical areas. However, no information is reported about the nature and structure of the arrowhead protein (AP). Herein, effects of slit divergent ultrasound (28, 33, 40 KHz frequencies at 30-50°C) and enzymatic (pepsin, trypsin, and alcalase) treatment on structure of AP were studied. In addition, changes in antioxidant activity of AP treated with ultrasound and enzymes were measured by chemical and cellular-based assays. The results showed that ultrasound treatment had considerable impact on the structure of AP and increased the susceptibility of AP to pepsin, trypsin and alcalase proteolysis. The changes in UV-Vis spectra, free sulfhydryl (SH) and disulfide bonds (SS) groups indicated that the structure of AP unfolded after ultrasound treatment. Besides, intrinsic fluorescence intensity of AP was increased by ultrasound treatment and then decreased after following enzymatic treatment. The circular dichroism (CD) analysis showed that ultrasound and enzymatic treatment decreased α-helix, β-turn of content of AP. However, the β-sheet and random coil content of AP increased. Interestingly, the AP after ultrasound and enzymatic treatment showed significant higher anti-oxidative activity in RAW 264.7 cells (p < 0.05) in comparison with control. In conclusion, the slit divergent ultrasonic provides a powerful endorsement for increasing the proteolysis of AP. Moreover, the improvement of the antioxidant activity of AP enzymatic hydrolysates provides a foundation of developing new type of plant-derived antioxidant peptides application.

    更新日期:2018-08-18
  • Ultrasound assisted synthesis of biodiesel from karanja oil by interesterification: Intensification studies and optimization using RSM
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-17
    Shubham S. Kashyap, Parag R. Gogate, Saurabh M. Joshi

    The present work deals with the optimization of interesterification of karanja oil using response surface methodology (RSM) with intensification studies based on the use of ultrasound. Esterification of karanja oil was performed as a pretreatment under fixed conditions of molar ratio of 1:10, catalyst loading of 3.5% and temperature of 60 °C to reduce the acid value from 10.5 mg of KOH/g to 1.8 mg of KOH/g. The pretreated oil was used for interesterification where the process parameters considered for optimization were time (X1), catalyst loading (X2), reactant ratio (X3) and duty cycle (X4) varied at three levels. The maximum yield of FAME achieved using optimum parameters as time of 35 min, catalyst loading of 1 wt %, reactant ratio of 1:9 (mol: mol) and duty cycle of 60% was 91.56% (on the basis of theoretical ester formation). The effect of reaction temperature was also studied keeping other parameters at optimum conditions and it was observed that yield increases with an increase in the temperature till 50 °C. It was also demonstrated that ultrasound assisted interestrification process gives less requirement of methyl acetate and catalyst as compared to the conventional process. It was also observed that higher yield was obtained in the presence of ultrasound (91%) as compared to the conventional method (60%). Kinetic studies established that second order rate equation fits the obtained data well. A mathematical model in RSM was successfully developed which can be used to make predictions about the expected conversions for this system.

    更新日期:2018-08-18
  • Preparation, characterization and investigation of sonophotocatalytic activity of thulium titanate/polyaniline nanocomposites in degradation of dyes
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-18
    Ali Sobhani-Nasab, Mohsen Behpour, Mehdi Rahimi-Nasrabadi, Farhad Ahmadi, Saeid Pourmasoud, Farideh Sedighi

    Thulium titanate/polyaniline nanocomposites were synthesized to observe the sonophotocatalytic degradation of dyes (widely used as a model pollutant) under ultrasonic irradiation and visible light. Based on our results, the synthesis process can improve sol-gel assisted sonochemical method in the presence of ultrasound and starch. To prepare pure thulium titanate nanostructures, the presence of starch and sonication treatment were concurrently obligatory. Therefore, sol-gel assisted sonochemical method can be used as a successful process for synthesis of thulium titanate nanostructures. According to the BET results, in the presence of ultrasound and starch surface area increased from 9.5305 m2/g to 40.28 m2/g. For verification of photacatalytic behavior of nanoparticles, several factors were studied. The nanocomposites/ultrasonic system showed greater photocatalytic activity for the degradation of Rh B rather than separately treatment of nanocomposites under visible light.

    更新日期:2018-08-18
  • Effect of different oils and ultrasound emulsification conditions on the physicochemical properties of emulsions stabilized by soy protein isolate
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-18
    Ahmed Taha, Tan Hu, Zhuo Zhang, Amr M. Bakry, Ibrahim Khalifa, Siyi Pan, Hao Hu
    更新日期:2018-08-18
  • Low Intensity Sonosynthesis of Iron Carbide@Iron Oxide Core-Shell Nanoparticles
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-17
    A.I. Argüelles-Pesqueira, N.M. Diéguez-Armenta, A.K. Bobadilla-Valencia, S.K. Nataraj, A. Rosas-Durazo, R. Ezquivel, M.E. Alvarez-Ramos, Roberto Escudero, P. Guerrero-German, J.A. Lucero-Acuña, P. Zavala-Rivera

    Here we demonstrate a simple method for the organic sonosynthesis of stable Iron Carbide@Iron Oxide core-shell nanoparticles (ICIONPs) stabilized by oleic acid surface modification. This robust synthesis route is based on the sonochemistry reaction of organometallic precursor like Fe(CO)5 in octanol using low intensity ultrasonic bath. As obtained, nanoparticles diameter sizes were measured around 6.38 nm ± 1.34 with a hydrodynamic diameter around 25 nm and an estimated polydispersity of 0.27. Core-Shell structure of nanoparticles was confirmed using HR-TEM and XPS characterization tools in which a core made up of iron carbide (Fe3C) and a shell of magnetite (γ-Fe2O3) was found. The overall nanoparticle presented ferromagnetic behavior at 4K by SQUID. With these characteristics, the ICIONPs can be potentially used in various applications such as theranostic agent due to their properties obtained from the iron oxides and iron carbide phases.

    更新日期:2018-08-17
  • In-situ reactive extraction of castor seeds for biodiesel production using the coordinated ultrasound – microwave irradiation: Process optimization and kinetic modeling
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-13
    Kartikkumar Thakkar, Keyur Shah, Pravin Kodgire, Surendra Singh Kachhwaha

    The present study demonstrates innovative and industrially viable in-situ biodiesel production process using coordinated ultrasound-microwave reactor. Reactive extraction process has been carried out by mixing grinded castor seeds with methanol in the presence of base catalyst (KOH). Response surface methodology coupled with central composite design has been applied for process optimization to achieve maximum yield. The result shows that maximum biodiesel yield of 93.5 ± 0.76 % was obtained under favorable conditions of: molar ratio (350:1), catalyst(w/w) (1.74%), reaction temperature (43°C) and reaction time (30 min). Regression equation obtained for the model having (R2), and (R2adj) equal to 0.9737 and 0.9507 respectively shows goodness of fit. First time reaction kinetics as well as oil extraction kinetics studies have been performed on coordinated ultrasound-microwave reactor. Assuming pseudo first order reaction activation energy was found to be 28.27 kJ.mol-1 and activation energy for oil extraction was observed to be 9.11 kJ mol-1. Estimated activation energy for the reaction kinetics and extraction kinetics was reduced by 27%, reaction rate constants were eight to ten times higher and diffusion coefficient was found to be two times higher in case of hybrid system as compared to conventional mechanical stirring technique. Estimated thermo-physical properties of biodiesel were found in agreement with ASTM and DIN standards in comparison to gasoline diesel.

    更新日期:2018-08-13
  • Reducing the residual stress in micro electroforming layer by megasonic agitation
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-11
    Chang Song, Liqun Du, Xuechao Ji

    In order to reduce the large residual stress in micro elelctroforming layer, megasonic assisted electroforming is proposed here. Micro electroforming experiments were performed with and without megasonic agitation, respectively. Four different megasonic power densities were applied to investigate the influence of megasonic agitation on reducing the residual stress. The residual stress was measured by X-ray diffraction (XRD) method. Experiment results show that the residual stresses fabricated with megasonic agitation are less than that fabricated without megasonic. When the megasonic power density is 2W/cm2, the residual stress can be the minimum value of -125.7 MPa, reduced by 60% in comparison with the value of -315.1 MPa electroformed without megasonic agitation. For exploring the mechanism of megasonic agitation on reducing the residual stress, the dislocation density and crystal orientation were calculated by the single-line Voigt profile analysis and Relative Texture Coefficient (RTC) method, respectively. The diameters and distributions of pits on the surface of electroforming layer were observed by the STM-6 tool microscope and counted by the Image-Pro Plus software. It reveals that one hand of the mechanism is the acoustic streaming produced by megasonic can strengthen the motion of dislocation in crystal lattice and makes the crystal lattices grow towards the equilibrium shape, which is benefit to crystallization with low residual stress. When the megasonic power density is 2W/cm2, the dislocation density increases to be the maximum value of 8.09×1015 m-2 and the difference between RTC(111) and RTC(200) decreases to be zero, which is consistent with the residual stress results. The other hand is that the stable cavitation produced by megasonic can provide residual stress release points during the electroforming process.

    更新日期:2018-08-13
  • Cavitation at filler metal/substrate interface during ultrasonic-assisted soldering. Part I: Cavitation characteristics
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-11
    Zhengwei Li, Zhiwu Xu, Lin Ma, Sheng Wang, Xuesong Liu, Jiuchun Yan

    The cavitation characteristics at filler metal/substrate interface during ultrasonic-assisted soldering were first recorded by high-speed photography in this work. Two kinds of bubbles, steady cavitation bubbles and transient cavitation bubbles were observed. Steady cavitation bubbles did not collapse within one acoustic period and could last longer than 50 acoustic periods. Transient cavitation bubbles formed and collapsed within one acoustic period. The cavitation process was divided into two stages based on the cavitation characteristics. The first violent cavitation stage was in fact the degassing process, which lasted approximately 2700 acoustic periods and was affected by the gas content trapped inside the filler metal and the stronger vibration at the initiation stage of ultrasonic-assisted soldering. The second steady cavitation stage had obvious low bubble density and accounted for the most of the soldering process. Higher cavitation densities were observed when small channel width and large ultrasonic power were used because of larger sound pressures inside the filler metal.

    更新日期:2018-08-13
  • Sonocatalysis of the magnetic recyclable layered perovskite oxides
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-11
    Xiaoning Li, Xiaofeng Yin, Wen Gu, Liuyang Zhu, Huan Liu, Guobin Zhang, Zhengping Fu, Yalin Lu

    Sonocatalysis is fascinating to utilize mechanical energy that universally exists in the environment. A big problem for the practical application of sonocatalysts is the incapability of recycle, which is necessary for resource saving and secondary pollution control. In this work, Bi7Fe2.75Co0.25Ti3O21 was firstly explored as a new sonocatalyst with magnetically recyclability. The magnetic catalysts can be easily collected with a magnetic bar after sonocatalytic reactions, and the structure and efficiency were kept after being recycled. Since the mechanism of sonocatalysis under ultrasonic vibration is still not fully understood, experiments including samples with different polarization and morphology, under different frequency and intensity of ultrasonic radiation were conducted. The results suggested that the sonocatalytic efficiency was in proportion to polarization instead of morphology and a possible mechanism of squeezed model was proposed.

    更新日期:2018-08-13
  • Ultrasond assisted synthesis of gallium hybrids for environmental remediation application
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-11
    Kousar Parveen, Uzaira Rafique, Muhammad Javed Akhtar, Muthupandian Ashokumar

    Micron-sized, rhombohedral shaped gallium hybrids with different indole derivatives (indole, 2-methyl-indole, indole-2-carboxylic acid) were successfully synthesized with precipitation method coupled with ultrasound followed by the post-grafting method. The as-synthesized hybrid materials were characterized using FTIR, SEM, XPS, XRD, and BET techniques. FTIR spectra showed characteristic absorption bands of gallium oxide and gallium hybrids at 400-700 cm-1 and 1400-1600 cm-1. SEM, XRD, and BET showed that ultrasound-assisted gallium micro-particles are porous, crystalline possessing high surface to volume ratio as compared to that synthesized in the absence of ultrasound. Survey scan of XPS revealed the presence of gallium, oxygen, nitrogen, and carbon. The as-synthesized gallium hybrids were applied as a potential photocatalyst towards Reactive Blue 4 (model pollutant) using batch adsorption experiment under visible light. It showed maximum 30-65% degradation within two hours and followed a pseudo-first-order kinetic model with R2 >0.9.

    更新日期:2018-08-13
  • State-of-the-art on the technique of dispersive Liquid-liquid microextraction
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-11
    Qiangfeng Wang, Renji Chen, William Shatner, Yan Cao, Yu Bai

    Dispersive liquid-liquid microextraction is a new sample pretreatment technology based on traditional liquid liquid extraction. In this paper, the application of low-toxicity extractants such as low-density extractants, auxiliary extractants, stripping agents and ionic liquids in this technology and the extraction modes such as solvent de-emulsification, suspension extractant curing, auxiliary extraction, back extraction, and ionic liquid-dispersion liquid microextraction, are summarized. In additon, the synergism of this technique with other sample preparation techniques, such as liquid-liquid extraction, solid-phase extraction, solid-phase microextraction, dispersive solid phase extraction, matrix solid-phase dispersion extraction, supercritical fluid extraction and ultrasound-assisted dispersive liquid-liquid microextraction is discussed.

    更新日期:2018-08-13
  • Experimental and numerical investigation on performance of a swirling jet reactor
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-11
    Giuseppe Mancuso

    In this work, a three-dimensional Computational Fluid Dynamic (CFD) analysis of a swirling jet reactor was implemented to gain a better understanding of fluid dynamics into the reactor. The effect of different geometries of the reactor, by considering different diameters of the injection slots of the reactor, on flow velocity and flow pressure distributions was investigated. Firstly, a one-phase model was implemented by considering only water into the reactor. Then, a two-phase model was defined including dissolved air into the water. The inlet flow pressure was set to 0.25 bar to consider non-cavitating conditions and, then, to get more accurate results on fluid dynamics into the reactor due to the absence of cavitating conditions. Data collected from experimental tests were used to calibrate and validate the model. Results of numerical simulations were in good agreement with experimental data, showing for all the geometries a rotating flow around the central axis of the reactor and at the exit of the double cone. The highest flow velocities and flow pressure drops were observed for the reactor geometry with the smallest injection slots diameters. Finally, noise measurements were performed during another set of experimental tests by considering different inlet flow pressures.

    更新日期:2018-08-13
  • Numerical simulation of single bubble dynamics under acoustic standing waves
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-11
    Sicong Qiu, Xiaojian Ma, Biao Huang, Guoyu Wang, Mindi Zhang

    The objective of this paper is to apply numerical method to simulate the single bubble dynamics under the acoustic standing waves, which is an extensive research of our previous work (Ma et al. Ultrason. Sonochem., vol. 42, 2018, pp. 619-630). The Navier-Stokes equation, which considers the acoustic radiation force caused by acoustic standing wave, is used to capture the transient shape variation, pressure fluctuation, and the direction of the bubble motion, especially for the case of the bubble near the rigid boundary. Several normalized parameters, such as acoustic pressure amplitude, acoustic wave number, and bubble size, are investigated in temporal and spatial scales to actively influence the direction of the liquid jet caused by bubble collapse. The numerical results show that due to the strong interaction with the acoustic standing wave, the bubble loses the spherical shape and generates a high-speed liquid jet. It worth noting that a significantly high pressure and velocity peak is respectively founded at the boundary wall, which is caused by the toroidal bubble collapse. Furthermore, in the standing wave field, single bubble would have distinctly different behaviors with the change of its resonance radius size. The high-speed liquid jet is always directed towards the node of an acoustic standing wave when the radius of bubble is larger than the resonance size, while the liquid jet is directed to the antinode when the radius of bubble is much smaller than the resonance size, closely with the primary Bjerknes force. Finally, the investigation shows that the single bubble will collapse much earlier during the deformation process with the increase of the normalized pressure amplitude.

    更新日期:2018-08-13
  • Numerical simulation of the coalescence of two bubbles in an ultrasound field
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-12
    Zheng Xu

    The coalescence of two bubbles under ultrasound irradiation is numerically investigated. The results indicate that ultrasound may accelerate the coalescence process, depending on the initial phase. The time-averaged nonzero Bjerknes force promotes bubble coalescence by dragging bubbles to nodes or antinodes, depending on their size. At the beginning of the coalescence process, a film forms between the two bubbles. The film drainage time first increases then decreases as a function of initial distance. This study contributes to an understanding of the effects of ultrasound on bubble coalescence.

    更新日期:2018-08-13
  • Ultrasonic-assisted coal beneficiation: A review
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-12
    Santosh Deb Barma

    Limited availability and large industrial demands of high-grade coals have forced many coal-dependent industries to shift their preference towards low-grade coals to meet the feedstock requirements. The low-grade coals due to their poor washability nature do not respond efficiently toward existing coal beneficiation techniques making the cleaning process challenging. Inefficient cleaning of such coals could potentially lead to environmental problems such as solid waste generation and gaseous emissions during combustion. Therefore, it is important to upgrade the existing coal beneficiation techniques for improving the clean coal quality, and simultaneously enhance the efficiency of the process. In the past few decades, many techniques have been developed to improve existing coal beneficiation techniques. Among them, ultrasound technology has gained significant attention due to its ability to enhance the process performance. The incorporation of ultrasound can significantly increase the clean coal yield under the substantial effect of cavitation and streaming. In this paper, an overview on the recent development in ultrasonic-based coal beneficiation techniques and the role of ultrasound in improving the efficiency of various coal beneficiation techniques are discussed. This includes a critical review of the ultrasound mechanism in enhancing coal demineralization, desulphurization, grindability, slurryability and dewatering.

    更新日期:2018-08-13
  • Influence of low-frequency ultrasound on the physico-chemical and structural characteristics of milk systems with varying casein to whey protein ratios
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-12
    Mayumi S. Silva, Bogdan Zisu, Jayani Chandrapala

    Casein and whey proteins respond differently to ultrasound treatment depending on the individual protein fraction and the delivered energy density. The main aim of this study was to determine the sonication-induced physiochemical and structural changes of protein solutions with varying casein to whey protein ratios as a function of processing time at 20 kHz ultrasound. Four different casein:whey protein ratios (80:20, 60:40, 50:50, 40:20) were prepared. Upon sonication, there was a reduction in particle size of the 80:20 and 60:40 ratios, but the particle size of 50:50 and 40:60 increased. Milk protein solutions with higher portion of caseins produced more hydrophobically driven aggregates while whey protein-rich milk protein solutions produced more disulphide mediated aggregates during sonication. Primarily, β-lactoglobulin was involved in the hydrophobic aggregation process and β-lactoglobulin, bovine serum albumin and κ-casein participated in the disulphide aggregation process at all ratios.

    更新日期:2018-08-13
  • Ultrasonic Polymerization of CuO@PNIPAM and its Temperature Tuning Glucose Sensing Behavior
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-09
    Fang Chen, Qi Cao, Chen Dong, Bo Shao, Wei Zhai, Xiaoyan Ma, Bingbo Wei

    The extraordinary high pressure and temperature produced during cavitation is crucial for ultrasonic sonochemisty. However, the cavitation effect is usually confined to a small zone nearby the ultrasonic horn, outside of which ultrasound produces much less effects on chemical reaction. In present work, in order to expand the range of effective zone and intensify the cavitation effect, N2 aeration was introduced to an ultrasonic polymerization process of CuO@PNIPAM in aqueous solution. By increasing the number of bubble nucleus gathered on the CuO surface and lowering the surface tension of the aqueous solution, the cavitation effect is intensified on the CuO surface within the whole reaction vessel, which benefits the covalently bonding of PNIPAM to CuO to a large degree and results in the formation of CuO@PNIPAM hybrid composite with excellent interfacial bonding. It is promising that the hybrid composite can be applied as temperature responsive glucose sensing platform with on and off states due to the wettability change of PNIPAM versus temperature.

    更新日期:2018-08-10
  • Ultrasound-assisted synthesis of metal organic framework for the photocatalytic reduction of 4-nitrophenol under direct sunlight
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-09
    S. Melvin Samuel, Jayanta Bhattacharya, C. Parthiban, Gayathri Viswanathan, N.D. Pradeep Singh
    更新日期:2018-08-10
  • Effects of ultrasound irradiation on the characterization and bioactivities of the polysaccharide from blackcurrant fruits
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-10
    Yaqin Xu, Yingying Guo, Suyang Duan, Hong Wei, Yusong Liu, Libo Wang, Xin Huo, Yu Yang

    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.

    更新日期:2018-08-10
  • Mechanism of multibubble sonochemiluminescence of Ru(bpy)32+ in neutral aqueous solutions
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-04
    G.L. Sharipov, A.M. Abdrakhmanov, L.R. Yakshembetova
    更新日期:2018-08-05
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  • Sonication induced effective approach for coloration of compact polyacrylonitrile (PAN) nanofibers
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-03
    Jatoi Abdul Wahab, Pardeep Kumar, Ick Soo Kim, Qing Qing Ni
    更新日期:2018-08-03
  • Achieving mainstream nitrogen removal via the nitrite pathway from real municipal wastewater using intermittent ultrasonic treatment
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-02
    Min Zheng, Shuang Wu, Qian Dong, Yanchen Liu, Xia Huang, Zhiguo Yuan

    Achieving mainstream nitrogen removal via the nitrite pathway (NH4+→NO2–→N2) is highly beneficial for energy neutral/positive wastewater treatment. Our previous batch assays revealed that ultrasonic treatment can suppress nitrite-oxidizing bacteria (NOB) while enhancing the activity of ammonia-oxidizing bacteria (AOB). Based on this concept, this study investigated the feasibility of applying ultrasonication to achieve the nitrite pathway in mainstream wastewater treatment. Two lab-scale sequencing batch reactors were set-up in parallel and fed with real municipal wastewater. With 100% of the sludge treated every 12 h at a treatment energy input of 0.066 kJ per mg mixed liquor suspended solids, the nitrite pathway was rapidly (within two weeks) established in the experimental reactor with stable effluent nitrite accumulation ratio (NO2–/(NO2– + NO3–)) of above 80% and significantly decreased NOB population. In comparison, the control reactor always possessed the conventional nitrification and denitrification pathway. Economic analysis indicated that energy consumption is too high for practical applications. However, this technology may be used in conjunction with other technologies, whereby this ultrasonic treatment can be used infrequently (e.g. once every few months) when the nitrite pathway becomes unstable.

    更新日期:2018-08-02
  • Physical insights of ultrasound-assisted ethanol production from composite feedstock of invasive weeds
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-01
    Arup Jyoti Borah, Mayank Agarwal, Arun Goyal, Vijayanand S. Moholkar
    更新日期:2018-08-01
  • Sonochemical fabrication of reduction-responsive magnetic starch-based microcapsules
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-01
    Lifeng Xu, Shuangling Zhong, Chao Shi, Yuexin Sun, Shengnan Zhao, Yan Gao, Xuejun Cui

    In this work, a novel, biocompatible, non-immunogenic and reductive-responsive magnetic starch-based microcapsules (RMSMCs) were designed and fabricated successfully via a facile sonochemical method for targeted delivery and triggered release of hydrophobic drugs. TEM image indicated that oleic acid (OA) modified Fe3O4 nanoparticles (OA-Fe3O4 NPs) were encapsulated into RMSMCs. The obtained RMSMCs were endowed with magnetism for drug targeted delivery because that the superparamagnetic OA-Fe3O4 NPs were encapsulated into RMSMCs. Moreover, Coumarin 6 (C6), a green fluorescent dye, was used as a model hydrophobic drug and loaded into RMSMCs. As drug carriers, the obtained spherical RMSMCs with the average size of 2μm presented excellent reductive-responsive release ability for hydrophobic drugs. Accordingly, the obtained RMSMCs would be promising carriers for targeted delivery and triggered release of hydrophobic drugs in biomedical applications.

    更新日期:2018-08-01
  • High-power ultrasound as pre-treatment in different stages of soymilk manufacturing process to increase the isoflavone content
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-07-31
    M. Morales-de la Peña, O. Martín-Belloso, J. Welti-Chanes

    Ultrasound (US) was applied as a pre-treatment in hydrated soybeans (HSB) and soybean slurry (SBS) during soymilk elaboration process to evaluate the feasibility of increasing the isoflavone content (IC) in the resultant soymilk. A predictive model and optimum US processing conditions were obtained by response surface methodology (RSM) using a three-level-three-factor Box-Behnken statistical design (BBD) in which US amplitude (50, 75, and 100 %), temperature (30, 45, and 60 °C), and time (20, 40, and 60 min) were selected as independent variables. Most of the US treatments applied in the HSB or SBS caused a significant increase (3 - 62%) in the total IC of the obtained soymilks over the control soymilk (6.97 mg/100mL). However, the IC of the resultant soymilks from sonicated HSB (11.38 mg/100 mL) was significantly higher than that in soymilk prepared from US-treated SBS (8.66 mg/100 mL). Experimental data were fitted into a 2nd-order-polynomial model and processing parameters were optimized (100% amplitude, 30°C, 20 min) to get the highest predicted and experimental IC, 11.38 and 12.8 mg/100 mL, respectively. These results indicated that US is a potential technology that could be implemented during soymilk manufacturing processing as pre-treatment of HSB to obtain soymilk with high isoflavone content and consequently better functionality.

    更新日期:2018-07-31
  • Development of ultrasound treated polyvinyl alcohol/tea polyphenol composite films and their physicochemical properties
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-07-31
    Yaowen Liu, Shuyao Wang, Weijie Lan, Wen Qin

    In this study, polyvinyl alcohol (PVA) was used as a film-forming substrate, added to extracted tea polyphenols (TPs) in various ratios and processed with ultrasonication to form films using the tape-casting method. The effects of ultrasonic processing duration on the properties of PVA/TP antibacterial active materials were explored via material property testing. The results showed that, overall, ultrasonic processing degraded the tensile strength and elongation at break of the composite films. When PVA/TP composite films with a PVA-to-TP mass ratio of 8:2 were processed with ultrasonication for 30 min, the swelling capacity was (740.19±64.67)% and solubility was (5.26±1.31)%. Ultrasonication also improved thedegradability and barrier properties of composite films. Moreover, 8/2 composite films with the PVA/TP ratio of 8:2 exhibited excellent bacteriostatic properties; after ultrasonication processing, the films had a bacteriostatic rate of (95.5±4.2)% and (91.8±3.7)% against Staphylococcus aureus and Escherichia coli, respectively, making them suitable for use as antibacterial active materials in food packaging.

    更新日期:2018-07-31
  • Effect of ultrasound treatment on swelling behavior of cellulose in aqueous N-methyl-morpholine-N-oxide solution
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-07-30
    Anwar J. Sayyed, Lalaso V. Mohite, Niteen A. Deshmukh, Dipak V. Pinjari

    The present study deals with the effect of ultrasound on the swelling and dissolution behavior of the cellulose pulp. Hardwood, acid sulfite cellulose pulp sheets were sonicated at different temperatures, operated at a fixed frequency (37 kHz) and power (320 watts) to break the intermolecular forces and hydrogen bonds of crystalline region. The obtained samples were evaluated for crystallinity, intrinsic viscosity, molecular weight (MW), molecular weight distribution (MWD) and surface morphology. It was observed that the crystallinity reduced from 61.9 to 18.9 % after 20 min of ultrasound treatment at 30°C, which was equivalent to the swelling at 75°C for 20 min without the use of ultrasound frequency. It was also found that ultrasound pre-treatment significantly decreased the particle size of the slurry and shortened the dissolution time and temperature requirement without affecting the cellulose solution quality.

    更新日期:2018-07-31
  • Can Sonochemistry take place in the absence of cavitation? – A complementary view of how ultrasound can interact with materials
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-07-29
    Mircea Vinatoru, Timothy J. Mason

    A hypothesis is advanced for a mechanism by which ultrasound could help to activate chemical reactions, even in the absence of cavitation. It is suggested that the compression phase of an acoustic wave could produce transient solid-like structures within the solution. These structures would result in an “ordering effect” of the molecules in which electrical charges could develop. Such electrical charges could facilitate electron movement from one molecule to another triggering therefore chemical reactions. Such reactions could occur even in the absence of cavitation especially if the solvent or reagents employed show piezoelectric/electrostriction properties. Similar transient ordering effects could be induced by the shockwave accompanying bubble collapse and these would help to explain some of the anomalous effects observed in sonochemistry under cavitation.

    更新日期:2018-07-30
  • Influence of ultrasound application and NaCl concentrations on brining kinetics and textural properties of Chinese cabbage
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-07-29
    Chang-Cheng Zhao, Jong-Bang Eun

    The effects of ultrasound application on the brining kinetics of Chinese cabbage leaves was evaluated at different NaCl concentrations (10, 15, and 20%) of the brine, and its influence on textural properties and salt distribution was also investigated. To identify the effects of these two factors on water and NaCl fluxes, the kinetics of transport was analyzed by taking the diffusion theory into account. The results showed that NaCl concentration and ultrasound application significantly affected moisture and NaCl transport. Based on Fick’s equation, the NaCl effective diffusivities were enhanced upon ultrasound application during the brining process, increasing from 147.09 to 812.22%. With regard to the textural properties, a higher content of NaCl resulted in lower textural profile values. Moreover, ultrasound application significantly increased the cabbage hardness. Scanning electron microscopy and energy dispersive x-ray mapping images showed the intensification of NaCl transport brought about by ultrasound application and by the increase in NaCl content, which confirms the results of the modeling analysis. Therefore, ultrasound could be a potential technology for accelerating the brining process of cabbage. These results have direct implications for the quality management of kimchi products.

    更新日期:2018-07-30
  • The intensification of amyloglucosidase-based saccharification by ultrasound
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-07-29
    Hugo M. Oliveira, Alice Q. Pinheiro, António J.M. Fonseca, Ana R.J. Cabrita, Margarida R.G. Maia

    The present report studied the role of ultrasound (US) energy in the amyloglucosidase-based starch hydrolysis using two complementary approaches: (i) in the activity of six commercially-available amyloglucosidases (using soluble starch as substrate), and (ii) in the hydrolysis of four pure starches from different botanical sources. This corresponds to the first systematic evaluation of the role of US in starch hydrolysis mediated by amyloglucosidase, being a consequence of our previous report that assessed the effect of US in the activity of alpha-amylase (LWT - Food Science and Technology 84 (2017) 674-685). Regarding amlyloglucosidases, three enzymes obtained from Aspergillus niger (AN1-AN3), and Spirizyme Achieve (SPA), Spirizyme Fuel (SPF) and Spirizyme Ultra (SPU) were submitted to a Box-Behnken experimental design in order to establish the optimum conditions for their maximum activity. In the presence of US, we found both inactivation and activation, ranging from -88% (AN3) to 699% (SPA). The US promoted the enzyme activity when combined with lower temperatures (40-60 °C), with a marked effect in Spirizyme enzymes. Based on the optimum conditions established by the experimental design, we also evaluated the role of US in the glucose yield resulting from the hydrolysis of pure starches (corn, rice, potato, wheat). In this case, US led to higher glucose yields in all conditions tested. The enhancement factors observed ranged from 1.2 (AN1, rice starch) to 65 (SPA, potato starch) times. We compared these findings with previous reports, which highlighted the role of US in intensifying amyloglucosidase-based saccharification in mild conditions, by simultaneously influencing both enzyme and substrate. Hence, US power has to be fine-tuned for each particular enzyme in order to maximize process intensification.

    更新日期:2018-07-30
  • Sono Hydrodistillation for Isolation of Citronella Oil: A Symbiotic Effect of Sonication and Hydrodistillation towards Energy Efficiency and Environment Friendliness
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-07-29
    Krishna P. Solanki, Meghal A. Desai, Jigisha K. Parikh

    Environmental benign approach for extraction of essential oil was made. An essential oil rich in citronellol, linalool and citronellal was extracted from the leaves of Cymbopogon winterianus using a clean hybrid extraction technique, sono hydrodistillation Sono hydrodistillation combines ultrasonic waves along with conventional hydrodistillation process to have symbiotic outcomes in terms of process improvement. Significant process parameters such as size of the plant material, extraction time, power, ultrasound amplitude, pulse interval and solid loading were investigated independently to study the effect on yield of oil and composition of oil. The water residue remained after extraction of volatile oil was analyzed using Folin-Ciocalteu method to determine the total phenolic content (TPC) which would help in assessing the residue as a useful byproduct. Substantial reduction in time was observed with the inclusion of ultrasound compared to conventional hydrodistillation. Further, to optimize the extraction conditions, observe interactive effects of various parameters and develop mathematical model, response surface methodology was employed. The maximum yield of oil was found to be 4.118 % at 21 min extraction time, 5 g solid loading, 250 mL water volume, 500 W heating mantle power, 70 % ultrasonic amplitude and 10:50 pulse interval. Total phenolic content was 13.84 mg GAE/g DM. The citronella oil was found to be composed of 27.47 % of linalool, 11.52 % of citronellal, 34.25 % citronellol and 11.15 % of elemol. Extraction time, solid loading and pulse interval had the significant influence on the yield of oil and total phenolic contents. Microscopic analysis has assisted in envisaging the probable mechanism indicating the role of sonication for rapid extraction. This novel technique was compared with the conventional hydrodistillation to ascertain the impact towards process intensification. Sono hydrodistillation was found to be a greener and cleaner process as energy consumption has been reduced by 40% while carbon footprint has shrunken by 47%.

    更新日期:2018-07-30
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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