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  • Intensification of industrial wastewater treatment using hydrodynamic cavitation combined with advanced oxidation at operating capacity of 70 L
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-10
    Saurabh M Joshi, Parag R Gogate

    The present work deals with treatment of industrial wastewater with hydrodynamic cavitation (HC) combined with advanced oxidation processes (AOPs) at a pilot plant operating scale of 70 L. Initially approach of only HC was studied with understanding into the effect of parameters like inlet pressure (range of 2-8 bar) and dilution factor (two cases as 1:1 and 1:3). Only HC was found to give minimal chemical oxygen demand (COD) removal within 180 min and the further focus of the study was to test efficiency of different oxidants in combination with HC. Oxidants used in treatment process are hydrogen peroxide (H2O2), Fenton, air and oxygen. Effect of H2O2 loading was analyzed with variation of loading in range of 5-15 g.L-1 and maximum COD removal of 30 % was achieved at 15 g.L-1 loading of H2O2. Keeping 15 g.L-1 as the constant loading of H2O2, optimization of Fenton based treatment was performed with variation of Fe2+/ H2O2 molar ratio in range of 1:10-1:30. Maximum COD removal of 42 % was achieved at best molar ratio of 1:20. For the very first time, air and oxygen injection were tested in combination of HC giving 15.5 % and 42 % COD removal respectively. Combination study of oxygen +Fenton+ HC was performed at H2O2 loading of 15 g.L-1 and Fenton molar ratio as 1:20, which resulted in 63 % COD removal within 180 min of treatment. Energy efficiency and cost calculations were also performed and for process giving 63 % COD removal in 180 min, cost of treatment obtained was 398 US$/m3. It was clearly established that HC in combination of Fenton and oxygen is the best approach for treatment of complex industrial wastewater.

    更新日期:2018-12-10
  • Facile Synthesis of Copper Sulfide Decorated Reduced Graphene Oxide Nanocomposite for High Sensitive Detection of Toxic Antibiotic in Milk
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-10
    Mani Govindasamy, Sea-Fue Wang, Sakthivel Kumaravel, R. Jothi Ramalingam, Hamad Al-lohedan

    The development of an effective technique for detecting antibiotic drug remains a serious task due to their toxicity to public health. For this purpose, herein, we report an electrochemical detection based on Cu2S nanospheres decorated reduced graphene oxide (RGO@Cu2S NC) nanocomposite. A sonochemical-assisted method was adopted to prepare the nanocomposite. Subsequently, it’s morphological, elemental, and crystal structural aspects were analyzed. The electrochemical properties were examined in order to ensure the material’s suitability in electrocatalytic sensing. RGO@Cu2S NC affixed screen-printed electrode found to exhibit tremendous electrocatalytic capability toward chloramphenicol (CAP) reduction. A sensitive and reproducible amperometric CAP sensor was fabricated which able to detect concentration as the nanomolar level. The method is worked well even in real samples (fresh milk samples) and the results are evaluated by HPLC method and amperometric methods.

    更新日期:2018-12-10
  • Ultrasonication-Assisted Synthesis of Sphere-Like Strontium Cerate Nanoparticles (SrCeO3 NPs) for the Selective Electrochemical Detection of Calcium Channel Antagonists Nifedipine
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-10
    Periyasamy Sundaresan, Raj Karthik, Shen-Ming Chen, Jeyaraj Vinoth Kumar, Velluchamy Muthuraj, E.R. Nagarajan

    In this work, strontium cerate nanoparticles (SrCeO3 NPs, SC NPs) were developed through facile synthetic techniques (Ultrasound-Assisted (UA) and Stirring-Assisted (SA) synthesis) and utilized as an electrocatalyst for the selective and sensitive electrochemical detection of calcium channel blocker nifedipine (NDF). The as-prepared UASC NPs and SASC NPs were characterized using XRD, Raman, TEM, EDS, mapping, XPS and BET analysis which exposed the formation of SC NPs in the form of spherical in shape and well crystalline in nature. BET studies reveal that UASC NPs have maximum surface area than that of SASC NPs. Further, the use of the as-developed UASC NPs and SASC NPs as an electrocatalyst for the detection of NDF. Interestingly, the UASC NPs modified screen printed carbon electrode (UASC NPs/SPCE) exhibited an excellent electrocatalytic activity in terms of lower reduction potential and enhanced reduction peak current when compared to SASC NPs and unmodified SPCE. Moreover, as-prepared UASC NPs/SPCE displayed wide linear response range (LR, 0.02 – 174 µM), lower detection limit (LOD, 5 nM) and good sensitivity (1.31 µAµM-1cm-2) than that of SASC NPs (LR = 0.02-157 µM, LOD = 6.4 nM, sensitivity - 1.27 µAµM-1cm-2). Furthermore, UASC NPs/SPCE showed an excellent selectivity even in the existence of potentially co-interfering compounds such as similar functional group containing drugs, pollutants, biological substances and some common cations/anions. The developed sensor was successfully employed for the determination of NDF in real lake water, commercial NDF tablet and urine samples with acceptable recovery.

    更新日期:2018-12-10
  • Ultrasonic energy-assisted preparation of β-cyclodextrin-carbon nanofiber composite: application for electrochemical sensing of nitrofurantoin
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-08
    Paramasivam Balasubramanian, Muthaiah Annalakshmi, Shen-Ming Chen, Tamilarasan Sathesh, T.S.T. Balamurugan

    A simple ultrasonic energy assisted synthesis of β-cyclodextrin (β-CD) supported carbon nanofiber composite (CNF) and its potential application in electrochemical sensing of antibiotic nitrofurantoin (NFT) is reported. The elemental composition, and surface morphology of the β-CD/CNF composite was validated through Field emission scanning electron microscopy, energy dispersive X-ray microscopy, Fourier transformer infrared microscopy, X-ray photoelectron microcopy and thermogravimetric analysis. The uniform enfolding of hydrophilic β-CD over CNF enhance the aqueous dispersion and offer abundant active surface to the β-CD/CNF composite. Further, the electrocatalytic efficacy of the β-CD/CNF composite is utilized to fabricate an electrochemical sensor for the high sensitive quantitative detection of NFT. Under optimized analytical conditions, the sensor displays a broad working range of 0.004-308 µM and calculated detection limit of 1.8 nM, respectively. In addition, the sensor showcased a good selectivity, storage and working stability, with amiable reproducibility. The point-of-care applicability of the sensor was demonstrated with NFT spiked human blood serum, and urine sample with reliable analytical performance. The simple, cost effective NFT sensor based on β-CD/CNF offered outstanding analytical performance in real world samples with higher reliability.

    更新日期:2018-12-09
  • A comparative study on de novo and ex novo lipid fermentation by oleaginous yeast using glucose and sonicated waste cooking oil
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-08
    Alok Patel, Leonidas Matsakas

    There are only a few reports available about the assimilation of hydrophobic substrates by microorganisms, however, it is well known that oleaginous microorganisms are capable of utilizing both hydrophilic and hydrophobic substrates and accumulate lipids via two different pathways namely de novo and ex novo lipid synthesis, respectively. In the present study, an oleaginous yeast, Cryptococcus curvatus, was investigated for its potentials to utilize a waste substrate of hydrophobic nature (waste cooking oil - WCO) and compared with its ability to utilize a hydrophilic carbon source (glucose). To facilitate the utilization of WCO by C. curvatus, the broth was sonicated to form a stable oil-in-water emulsion without adding any emulsifier, which was then compared with WCO samples without any ultrasound treatment (unsonicated) for the yeast cultivation. Ultrasonication reduces the size of hydrophobic substrates and improves their miscibility in an aqueous broth making them easily assimilated by oleaginous yeast. Under de novo lipid fermentation, the yeast synthesized 9.93 ± 0.84 g/L of cell dry weight and 5.23 ± 0.49 g/L lipids (lipid content of 52.66 ± 0.93 %) when cultivated on 40 g/L of glucose (C/N ratio of 40). The amount of cell dry weight, lipid concentration, and lipid content were considerably higher during the ex novo lipid synthesis. More specifically, the highest lipid content achieved was 70.13 ± 1.65 % w/w with a corresponding dry cell weight and lipid concentration of 18.62 ± 0.76 g/L and 13.06 ± 0.92 g/L respectively, when grown on 20 g/L sonicated WCO. The highest lipid concentration, however, was observed when the yeast was cultivated on 40 g/L sonicated WCO. Under these conditions, 20.34 g/L lipids were produced with a lipid content of 57.05% w/w. On the other hand, lipid production with unsonicated WCO was significant lower, reaching 11.16 ± 1.02 g/L (69.14 ± 1.34 % w/w of lipid content) and 12.21 ± 1.34 g/L (47.39 ± 1.67 % w/w of lipid content) for 20 g/L and 40 g/L of WCO, respectively. This underpins the significance of the sonication treatment, especially at elevated WCO concentrations, to improve the accessibility of the yeast to the WCO. Sonication treatment that was used in this study assisted the utilization of WCO without the need to add emulsifiers, thus reducing the need for chemicals and in turn has a positive impact on the production costs. The microbial lipids produced presented a different fatty acid composition compared to the WCO, making them more suitable for biodiesel production as suggested by the theoretical estimation of the biodiesel properties.

    更新日期:2018-12-09
  • Ultrasound-assisted water-in-palm oil nano-emulsion: Influence of polyglycerol polyricinoleate and NaCl on its stability
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-08
    Revathi Raviadaran, Ng Mei Han, Sivakumar Manickam, Davannendran Chandran

    This study aimed to formulate a stable palm oil-based water-in-oil (W/O) nano-emulsion. Emphasis was placed on the effects of polyglycerol polyricinoleate (PGPR), medium chain triglyceride (MCT), lecithin and sodium chloride (NaCl) addition towards the stability of nano-emulsion. Among the performed analyses were mean droplet diameter (MDD), dispersity index (DI), critical micelle concentration (CMC), lipid peroxidation, viscosity, sedimentation index (SI) and surface morphology. The most stable optimized palm oil-based W/O nano-emulsion was produced using 61.25 wt% of palm oil, 26.25 wt% of MCT, 2.5 wt% of PGPR and 10 wt% of water (0.5M of NaCl). The MDD and DI of the obtained W/O nano-emulsion were 143.1±8.8 and 0.131±0.094, respectively. After 2 weeks, no sedimentation was observed in W/O nano-emulsion with MDD and DI were 151.2±6.5 nm and 0.156±0.025 respectively. This study clearly found that polyricinoleate non-polar fatty acids of PGPR bound to non-polar fatty acids of palm oil through van der Waals intermolecular forces. While, polyglycerol polar head of PGPR interacts with water molecules through hydrogen bonding, as well as by the bound glyceride units of palm oil. The addition of NaCl further reduced MDD by 70 nm and improved the stability of nano-emulsion through electrostatic and steric repulsions attributed to the dissociation of Na+ and Cl- ions. This study aids to widen the knowledge and interest on the utilization of palm oil for the generation of W/O nano-emulsion, as well as to better understand the interaction between palm oil and PGPR/NaCl in producing nano-emulsion.

    更新日期:2018-12-09
  • Low-intensity ultrasound induced cavitation and streaming in oxygen-supersaturated water: Role of cavitation bubbles as physical cleaning agents
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-05
    Tatsuya Yamashita, Keita Ando

    A number of acoustic and fluid-dynamic phenomena appear in ultrasonic cleaning baths and contribute to physical cleaning of immersed surfaces. Propagation and repeated reflection of ultrasound within cleaning baths build standing-wave-like acoustic fields; when an ultrasound intensity gradient appears in the acoustic fields, it can in principle induce steady streaming flow. When the ultrasound intensity is sufficiently large, cavitation occurs and oscillating cavitation bubbles are either trapped in the acoustic fields or advected in the flow. These phenomena are believed to produce mechanical action to remove contaminant particles attached at material surfaces. Recent studies suggest that the mechanical action of cavitation bubbles is the dominant factor of particle removal in ultrasonic cleaning, but the bubble collapse resulting from high-intensity ultrasound may be violent enough to give rise to surface erosion. In this paper, we aim to carefully examine the role of cavitation bubbles from ultrasonic cleaning tests with varying dissolved gas concentration in water. In our cleaning tests using 28-kHz ultrasound, oxygen-supersaturated water is produced by oxygen-microbubble aeration and used as a cleaning solution, and glass slides spin-coated with silica particles of micron/submicron sizes are used to define cleaning efficiency. High-speed camera recordings and Particle Image Velocimetry analysis with a pressure oscillation amplitude of 1.4 atm at the pressure antinode show that the population of cavitation bubbles increases and streaming flow inside the bath is promoted, as the dissolved oxygen supersaturation increases. The particle removal is found to be achieved mainly by the action of cavitation bubbles, but there exists optimal gas supersaturation to maximize the removal efficiency. Our finding suggests that low-intensity ultrasound irradiation under the optimal gas supersaturation in cleaning solutions allows for having mild bubble dynamics without violent collapse and thus cleaning surfaces without cavitation erosion. Finally, observations of individual bubble dynamics and the resulting particle removal are reported to further support the role of cavitation bubbles as cleaning agents.

    更新日期:2018-12-06
  • Simulation of cavitation enhanced temperature elevation in a soft tissue during high-intensity focused ultrasound thermal therapy
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-05
    E.M. Zilonova, M. Solovchuk, T.W.H. Sheu

    The present study aims to investigate temperature distribution caused by bubble oscillations in a soft tissue during focused ultrasound therapy by introducing a coupled temperature-cavitation model. The proposed model is capable of describing bubble dynamics, viscoelastic properties of surrounding tissue-like medium, temperature distribution inside and outside the bubble, vapor diffusion within the bubble and vapor flux through the bubble wall to the exterior. The continuous temperature distribution inside and outside the oscillating bubble in soft tissue subject to ultrasound wave with high acoustic pressure is presented. The temperature close to the bubble wall can reach the value of about 10 3 K. The elasticity of soft tissue reduces temperature values. The relaxation time effect strongly depends on the period of the ultrasound wave. If the vapor mass flux effect is taken into account in the simulations, the rectified growth effect can be observed, which can lead to the decrease of the temperature values. Due to the growth of the bubble, the effects of elasticity and relaxation time on the temperature become less prominent during several bubble oscillation cycles. The impact of cavitation heat source terms on the exterior temperature was examined and led us to draw conclusion that, even though these heat sources can increase the outside temperature values, they can not be treated as main mechanisms for the temperature elevation during a few microseconds. The performed comparison with uncoupled conventional model for the outside temperature calculation revealed that coupling with inside temperature model delivers incomparably higher values to the bubble’s exterior and, therefore, it is essential for the accurate description of the treatment process.

    更新日期:2018-12-06
  • Ultrasound-Enhanced Hair Dye Application for Natural Dyeing Formulations
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-05
    V. Gonzalez, R. Wood, J. Lee, S. Taylor, M.J. Bussemaker

    Advances made in recent years have allowed the application of colorants obtained from natural sources into textile dyeing. The use of ultrasound in the dyeing method is reported to increase dye uptake and decrease dyeing times. The aim of this work is to further extend the knowledge of natural hair dyes considering the use of ultrasound in the dyeing method with commercially available herbal dyes and using goat hair as a model for human hair. Optimal ultrasonic parameters were selected by considering the effects of sonication times (5, 10 and 15 min), frequencies (44, 400 and 1000 kHz) and total dyeing times (30, 60 and 120 min) in the morphology of the dyed hair and the colour intensity. Damage to the hair surface was evaluated by scanning electron microscopy (SEM) images, differences in colour of the dyed hair was obtained by ImageJ analysis and quantification of dye uptake was determined by UV-visible spectroscopy. The evidence from this study suggests an increase in goat hair coloration with the use of ultrasonic energy. Optimal dyeing conditions in consideration of colouration efficacy without hair damage were identified as sonication at 400 kHz for 10 min with a total dyeing time of 60 min.

    更新日期:2018-12-06
  • Experimental and numerical investigation of cavitation-induced erosion in thermal sprayed single splats
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-05
    Yan Wang, Bruno Lebon, Iakovos Tzanakis, Yongli Zhao, Kuaishe Wang, Jorge Stella, Thierry Poirier, Geoffrey Darut, Hanlin Liao, Marie-Pierre Planche

    Hydraulic components are coated by thermal spraying to protect them against cavitation erosion. These coatings are built up by successive deposition of single splats. The behavior of a single splat under mechanical loading is still very vaguely understood. Yttria-stabilized zirconia (YSZ) and stainless-steel splats were obtained by plasma spraying onto stainless steel substrates. The velocity and temperature of particles upon impact were measured and the samples were subsequently exposed to cavitation erosion tests. An acoustic cavitation simulation estimated the water jet velocity and hammer stresses exerted by bubble collapse on the surface of the specimen. Although the results suggested that high stress levels resulted from cavitation loading, it was clear that weak adhesion interfaces played a crucial role in the accelerated cavitation-induced degradation.

    更新日期:2018-12-06
  • Ultrasound assisted synthesis of reduced graphene oxide (rGO) supported InVO4-TiO2 nanocomposite for efficient Hydrogen production
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-06
    Hafeez Yusuf Hafeez, Sandeep Kumar Lakhera, Muthupandian Ashokkumar, Bernaurdshaw Neppolian

    Herein, a ternary nanocomposite, comprising metal oxide (InVO4 and TiO2) photocatalysts supported on rGO sheets was prepared via the hydrothermal method in the presence and absence of ultrasound irradiation. The photocatalytic performance of the prepared rGO/InVO4-TiO2 nanocomposites was evaluated for H2 evolution activity from water splitting with glycerol as a sacrificial agent. Interestingly, a synergistic effect (6-fold) was observed with rGO/InVO4-TiO2 nanocomposite prepared with the help of ultrasound compared to the samples prepared without ultrasound. The optimized nanocomposite (rGO/InVO4-TiO2) exhibited a maximum H2 evolution of 1669 μmol h-1, a ∼13-fold enhancement compared to the bare TiO2. This remarkable enhancement is mainly due to the synergistic effect induced by ultrasonic irradiation along with the shifting of the optical band gap of TiO2 from 3.20 eV to 2.80 eV by loading of InVO4 and rGO and also strong chemical bonding between metal (Ti) and C through Ti-C bond formation, as identified by UV-vis DRS spectra and XPS spectra, respectively. Moreover, a significant quenching of PL emission intensity and smaller radius arc of the Nyquist plot in the EIS were observed when the rGO and InVO4 were loaded in TiO2, indicating the efficient charge carriers separation and transfer in the presence of rGO sheet, resulting in enhanced photocatalytic activity. Thus, application of ultrasound has played significant and important roles in substantially enhancing hydrogen evolution along with rGO and InVO4 acting as support and co-catalyst, respectively.

    更新日期:2018-12-06
  • Experimental Study of Waste Activated Sludge Treatment Using a Rotational Hydrodynamic Cavitation Generator and Ultrasonication
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-04
    Hyun Soo Kim, Seung Ho Lee, Xun Sun, Joon Yong Yoon

    In the present work, the performance of a waste-activated sludge (WAS) treatment using a novel rotational hydrodynamic cavitation generator (RHCG) was investigated. To verify the performance, a comparison with an ultrasonic device was conducted in four experimental cases at the same specific energy input using three assessment factors. The RHCG consisted of a rotor and three covers with inserted dimples. Ultrasonication was performed using a general ultrasonic bath. The experimental parameters were established to calculate the specific energy input of the sludge passing through the RHCG for a total of 5, 10, 15, and 20 times. Disintegration performance using particle size distribution and SVI, solubilization rate using soluble COD, and oxidation performance using total COD and VSS reduction rate were analyzed as assessment factors. For oxidation and particle disintegration, the RHCG showed overwhelming performance and was superior to the ultrasonic device at low energy input. The tCOD and VSS of the sludge treated five times in the RHCG were reduced by 52.9 and 66.0 %, respectively, and the median particle size of the sludge treated 10 times in the RHGG was reduced by 92.7 %. Otherwise, at comparable specific energy inputs, sludge treated by the ultrasonic device were reduced by 0, 26.4, and 67.6 %, respectively. However, due to the contradictory interactions of particle disintegration and oxidation, the two treatment methods showed similar performance in terms of solubilization rate and reached up to 42.3 and 41.4 % in the RHCG and ultrasonic device, respectively. In the present work, the RHCG is proposed as a new novel WAS treatment technique.

    更新日期:2018-12-05
  • Hybrid reactor based on hydrodynamic cavitation, ozonation, and persulfate oxidation for oxalic acid decomposition during rare-earth extraction processes
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-04
    Jongbok Choi, Mingcan Cui, Yonghyeon Lee, Junjun Ma, Jeonggwan Kim, Younggyu Son, Jeehyeong Khim

    A cost-effective method for treating oxalic acid (OA) during rare-earth extraction was developed using hydrodynamic cavitation (HC), ozone (O3), and persulfate (PS) (HC@PS@O3 process). The results showed that the optimal inlet pressure during HC was 5.10 kg cm−2 with an orifice plate diameter of 2 mm. Moreover, HC was shown to activate PS, providing an alternative activation method to base or heat as an ultrasound activation method for chemical oxidation. O3 was also shown to activate PS. For OA oxidation using the HC@PS@O3 process, the optimum pH was 3 and the reaction rate increased with increasing temperature. Further, the activation energy was 36.69 kJ mol−1. The mechanisms unveiled in this study will allow optimization of the HC@PS@O3 process as a chemical oxidation technology. The kinetic investigation and economic evaluation of the HC@PS@O3 process can be used as the basis for real wastewater treatment processes in the future.

    更新日期:2018-12-04
  • Ultrasound–Assisted Biodiesel Production Using Heterogeneous Base Catalyst and Mixed Non–edible Oils
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-04
    Ritesh S. Malani, Vivek Shinde, Sumedh Ayachit, Arun Goyal, Vijayanand S. Moholkar

    In the present study, the ultrasound–assisted biodiesel production from mixed feedstock of non–edible oils in presence of KI impregnated ZnO as a catalyst in batch reactor was investigated. The production was optimized by using two approaches (1) feedstock optimization and (2) process parameters optimization. Various non–edible oils at optimum volumetric ratio were blended and used as feedstock for transesterification reaction. Biodiesel yield was optimized by Box–Behnken statistical design. The maximum triglyceride conversion of 92.35 ± 1.08% was achieved at optimized conditions of catalyst loading = 7 % (w/w); alcohol/oil molar ratio = 11.68:1 and reaction temperature = 59°C. Transesterification process with mechanical agitation was used as base case for identification of role of sonication in the process. The transesterification process was analysed for kinetic behaviour using pseudo first order kinetics and Eley–Rideal mechanism based model. Overall activation energy of transesterification process for mechanically agitated and ultrasound–assisted systems was calculated as 135.4 and 123.65 kJ/mol, respectively. However, the sum of activation energies of three reaction steps of Eley–Rideal mechanism (64.69 kJ/mol and 46.63 kJ/mol, for mechanically agitated and ultrasound–assisted system, respectively) was much lower. This discrepancy is attributed to mass transfer limitations in the system, even in presence of sonication.

    更新日期:2018-12-04
  • Acoustic Cavitation Assisted Plasma for Wastewater Treatment: Degradation of Rhodamine B in aqueous solution
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-04
    Yu Fang, Daiki Hariu, Takuya Yamamoto, Sergey Komarov

    A novel wastewater treatment process, acoustic cavitation assisted plasma (ACAP) is proposed in this study aiming at expanding the treatable range of water pollutants due to a synergetic effect of ultrasound irradiation and high voltage plasma discharge. In this process, the role of acoustic cavitation is not only to provide generation of chemically active OH⋅ radicals, as for example in conventional ultrasonic wastewater treatment techniques, but also to ensure conditions for stable plasma generation in wastewater and, thus, to extend the treatable range of water pollutants. Rhodamine B (RhB) was used as a model pollutant in experiments examining effects of ultrasound amplitude, RhB initial concentration, output voltage, solution pH and electrical conductivity on the RhB degradation efficiency. The results revealed that the ultrasound-assisted plasma generation requires lower output voltages and allows to increase the acceptable range of electrical conductivity of treatable solutions up to 1000 μS/cm, that is about 24 times higher than in the case of conventional plasma discharge treatment. The alkaline and acid medium were found to be favorable for higher degradation efficiency. Additional measurements and results of recent investigations concerning underwater plasma showed that microbubbles presented in cavitation zone could serve as “bridges” making the pulse discharge propagation between the electrodes easier than in the conventional case. Besides, acoustic cavitation assists a faster transition of plasma discharge from ineffective streamer type to more effective spark type that further contributes to the improvement of the treatment performance.

    更新日期:2018-12-04
  • Ultrasonic degradation of Persian gum and gum tragacanth: effect on chain conformation and molecular properties
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-03
    Nassim Raoufi, Rassoul Kadkhodaee, Yapeng Fang, Glyn O. Phillips

    The present study introduces the ultrasonic modification of two Iranian native gum exudates, Persian gum (PG) and gum tragacanth (GT) for the first time. They were sonicated at a constant frequency of 20 kHz and temperature of 60 °C for various times (0, 2, 5, 10, 20, 30 and 40 min) and the changes in their molecular properties were investigated using oven drying, gel permeation chromatography-multiangle laser-light scattering (GPC-MALLS), rheometery and FTIR analysis. Results indicated that the soluble dry mass of both hydrocolloids was extensively enhanced (from less than 10% at time zero to more than 90% at the end of treatment time) by sonication. Moreover, the molecular weight and viscosity of gums dispersions was decreased with the increase of the treatment time. Fracture in polysaccharide chains was confirmed by analysis of the molecular weight parameters. Calculation of chain breaks and polydispersity index (PDI) revealed that scissions occurred at the backbone as well as the side branches. PG, owing to its higher molecular weight, displayed more extensive and faster degradation than GT. However, the chain rupture of GT was twice more than that of PG at the end of sonication time. The specific volume for gyration (SVg) and molecular density (ρ) showed that intact PG contains compactly packed molecules with greater number of cross-linked bonds than GT. Furthermore, the conformational changes into semi-flexible chains and worm-like coils were determined for both gums after 40 min sonication. Variation of the molecular density along with the FTIR analysis demonstrated that ultrasonication broke C-O-C bonds in both PG and GT leading to more flexible chains.

    更新日期:2018-12-03
  • Sonication technique to produce emulsions: The impact of ultrasonic power and gelatin concentration
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-03
    Karen Cristina Guedes Silva, Ana Carla Kawazoe Sato

    The production of food emulsions has increased the demand for processes, natural emulsifiers and stabilizers that provide reasonable stability. This study approaches the influence of parameters that affect the stability of emulsions produced by sonication, such as ultrasonic power (150, 225 and 375 W) and gelatin concentration, when producing alginate, potato starch and gelatin stabilized emulsions. The results showed that sonication reduced viscosity, surface charge and improved the interfacial properties of biopolymeric solutions. Emulsions presented visual kinetic stabilization after 7 days of storage. The increase of sonication power reduced particle size but increased flocculation. The use of ultrasonic power at 225 and 375 W and gelatin in a concentration above 1.0% resulted in stable emulsions with smaller particle size, which is desirable for its application in food systems.

    更新日期:2018-12-03
  • Eu-doped ZnO nanoparticles: Sonochemical synthesis, characterization, and sonocatalytic application
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2015-03-30
    Alireza Khataee, Atefeh Karimi, Mahmoud Zarei, Sang Woo Joo

    Undoped and europium (III)-doped ZnO nanoparticles were prepared by a sonochemical method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) analysis. The crystalline sizes of undoped and 3% Eu-doped ZnO were found to be 16.04 and 8.22 nm, respectively. The particle size of Eu-doped ZnO nanoparticles was much smaller than that of pure ZnO. The synthesized nanocatalysts were used for the sonocatalytic degradation of Acid Red 17. Among the Eu-doped ZnO catalysts, 3% Eu-doped ZnO nanoparticles showed the highest sonocatalytic activity. The effects of various parameters such as catalyst loading, initial dye concentration, pH, ultrasonic power, the effect of oxidizing agents, and the presence of anions were investigated. The produced intermediates of the sonocatalytic process were monitored by GC–Mass (GC–MS) spectrometry.

    更新日期:2018-12-02
  • Bubble size measurements in different acoustic cavitation structures: filaments, clusters, and the acoustically cavitated jet
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-05-16
    Fabian Reuter, Sergey Lesnik, Khadija Ayaz-Bustami, Gunther Brenner, Robert Mettin

    Acoustic cavitation typically forms a variety of bubble structures of generally unknown and wide size distributions. As the bubbles strongly oscillate, their (equilibrium) sizes are not directly observable. Here, a method is presented to experimentally determine the size distribution in bubble populations from high speed imaging of the bubbles in oscillation. To this end, a spherical bubble model is applied in statistical fashion. This technique is applied to several experimentally realized bubble structures: streamer filaments, clusters, and a peculiar structure we report here on, the acoustically cavitated jet. It is generated by the sonication of a submerged jet to produce abundant cavitation already at low flow velocities. Our analysis is complemented by numerical exploration of the hydrodynamic and acoustic properties of the experimental configuration in which the observed bubble structures are formed.

    更新日期:2018-12-02
  • The effect of high intensity ultrasound (HIU) on the kinetics of crystallization of sucrose: Elimination of latent period
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-05-26
    Kaman Singh, Satya Prakash Gupta, Ashok Kumar, Ajay Kumar

    The application of a technique to eliminate the latent period during crystallization of sucrose by high intensity ultrasound (HIU) was investigated in this paper. Employing HIU (20 kHz, 750 W) to crystallization of sucrose, latent period was eliminated and it was found to obey first order kinetics (K ∼10−5s−1) in the temperature range of 30–50 °C. Employing Arrhenius equation, the average energy of activation (Ea) estimated as 5.0 kcal mol−1. Traditional knowledge indicates that crystallization is sufficiently spontaneous; however, the magnitude of “K” and other thermodynamic quantities of the process indicate that crystallization is actually a slow process. Generally, chemical reactions which posses low rate constants, need the high energy of activation. On the contrary, the energy of activation is appreciably less. The energy of activation with a rate constant of the order of 10−5s−1 could be predicted of the order of 20 kcal mol−1 at 27 °C. The low energy of activation for crystallization of sucrose is of interest. A very interesting elucidation can be had from neutron diffraction data and transport property of the sucrose which is discussed in details in this paper.

    更新日期:2018-12-02
  • Correlations between disintegration degree of fruit skin cells induced by ultrasound and efficiency of bio-compounds extraction
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-01
    Lu Wang, Nadia Boussetta, Nikolai Lebovka, Caroline Lefebvre, Eugène Vorobiev

    The ultrasound (US) assisted extraction of bio-compounds from different fruit skins (apples, bananas and persimmons) was studied. The aqueous suspensions of skins were treated by US with different energy inputs (0.033-0.299 kW·h/kg) and total time of aqueous extraction was up to 2700 s. The ionic, Zi, and total polyphenol, Zp, extraction indexes of the liquid extracts were analyzed. From microscopic images the cell wall disintegration index, Zm, was determined. Increase in US energy input caused the increase of values of Zi, Zp and Zm. The correlations between extraction parameters and the disintegration index, Zm, were discussed.

    更新日期:2018-12-01
  • Modification of quinoa flour functionality using ultrasound
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-12-01
    Fan Zhu, Hang Li

    Ultrasound has potential to modify physicochemical properties of food systems. Quinoa (Chenopodium quinoa) has become more popular due to the attractive nutritional quality. Whole grain quinoa flour was treated by ultrasound (20 kHz, 250 W) to different time length (up to 19 h). The treatment for more than 5 h significantly increased the water solubility and in vitro starch digestibility of quinoa flour, while decreasing the gelatinization temperatures and enthalpy change, viscosity during pasting event, gelling capacity, in vitro antioxidant activity, and total phenolic content. These changes were seen to depend mostly on treatment time, and indicated degradation and modifications of the chemical components (starch in particular) of quinoa flour. This study suggests the potential of ultrasound as a non-thermal processing tool to modify grain flour functionality.

    更新日期:2018-12-01
  • Sonication induced effective approach for coloration of compact polyacrylonitrile (PAN) nanofibers
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-08-03
    Abdul Wahab Jatoi, Pardeep Kumar Gianchandani, Ick Soo Kim, Qing-Qing Ni

    We present our research on dyeability of polyacrylonitrile (PAN) nanofibers following ultrasonic dyeing method. Although PAN has been extensively utilized in textile apparel, sportswear, upholstery and home furnishing, however, coloration of PAN nanofibers has not yet been reported. PAN is a compact fiber while the nanofiber structure makes it more difficult to color PAN nanofibers. PAN is generally dyed with basic dyes and dyeing is carried out in acidic conditions, while the dyeing process takes about two hours at boiling temperature. A systematic study on dyeability of PAN nanofibers will extend its use in textile apparel industry. Thus, we used ultrasonic energy and first time conducted our research on dyeability of electrospun PAN nanofibers using disperse dyes. Dyeing process parameters such as dyeing time, temperatures and concentrations of dyes were optimized. Ultrasonic dyeing of PAN nanofibers was compared with its conventional dyeing as well. Affect of ultrasonic dyeing on the morphology, chemical state, crystallographic structure and mechanical strength of PAN nanofibers has been studied. PAN nanofiber samples were characterized by SEM, FTIR, XRD and tensile strength tests. The results revealed 80 °C and 60 min as optimum temperature and time for ultrasonic dyeing of PAN nanofibers. The ultrasonic dyeing does not affect morphology, chemical and crystalline structure of the PAN nanofibers while it improves their mechanical strength. Our research suggests dyeability of PAN nanofibers with disperse dyes by ultrasonic method and their subsequent use in textile apparels.

    更新日期:2018-11-29
  • 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

    The effect of hydrated electron scavengers, Cd2+, NO3−, (CH3)2CO, and OH radical scavengers, Cl−, I−, on the intensity of Ru(bpy)32+ ion sonochemiluminescence observed in neutral aqueous solutions of Ru(bpy)3Cl2 was studied. The variation trends in the luminescence intensity due to the action of the scavengers indicated three main reactions sufficient to explain the sonochemiluminescence in a neutral medium. These reactions are the Ru(bpy)32+ reduction and oxidation with the H atom and the OH radical, respectively, and disproportionation of the Ru(bpy)3+ and Ru(bpy)33+ ions thus formed, giving rise to the multibubble sonochemiluminescence emitter, namely, the electronically excited ∗Ru(bpy)32 ion.

    更新日期:2018-11-29
  • 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 addition, 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:2018-11-29
  • Valorisation of baobab (Adansonia digitata) seeds by ultrasound assisted extraction of polyphenolics. Optimisation and comparison with conventional methods
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-26
    Balarabe B. Ismail, Mingming Guo, Yunfeng Pu, Wenjun Wang, Xingqian Ye, Donghong Liu

    In this study, ultrasound-assisted extraction (UAE) of phenolic compounds in baobab (Adansonia digitata) seeds was optimised using RSM. Based on the single factor experiment results, the effect of four parameters, extraction time (10 - 20 min), temperature (40 - 60°C), % amplitude (30 - 50) and solvent to solid ratio (20-30, mL/g) on Total Flavonoids Content (TFC) were investigated and optimised using a central composite design (CCD). The predicted optimal conditions with the highest desirably (0.874) were: 20 min, 30% amplitude, 60°C temperature and 30 mL/g solvent to solid ratio. Under these conditions, the experimental TFC value (1633.84 ± 10.75 mg RE/100 g DW) was highly correlated with the predicted value (1631.77 mg RE/100 g DW). Moreover, a comparative study confirmed that the recovery of TFC, TPC and antioxidant activity (DPPH and FRAP) was significantly higher in UAE than maceration and Heat Assisted Extraction (HAE) extraction methods in addition to a shorter extraction time. HPLC analysis of the UAE optimised sample extract revealed the presence of 10 phenolic compounds with the highest concentration of D-(+) catechin (87.18 ± 14.57 µg/g). This study is the first attempt to optimise UAE parameters for the extraction of phenolic compounds in baobab seeds.

    更新日期:2018-11-27
  • Structural investigation of a new cadmium coordination compound prepared by sonochemical process: crystal structure, Hirshfeld surface, thermal, TD-DFT and NBO analyses
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-26
    A. Masoudiasl, M. Montazerozohori, S. Joohari, L. Taghizadeh, G. Mahmoudi, A. Assoud

    A new nanostructured cadmium complex containing a tridentate Schiff base ligand was sonochemically synthesized and characterized by XRPD, FT/IR, NMR, and single crystal X-ray crystallography. Structural data showed that cadmium(II) ion is surrounded by three nitrogen atoms of Schiff base ligand and two iodide anions. The crystal packing was contained the intermolecular interactions such as C–H···O, C–H···I and π···π interactions organizing the self-assembly process. Hirshfeld surfaces and corresponding fingerprint plots have been used for investigation of the nature and proportion of interactions in the crystal packing. FT/IR, NMR and XRD data were in agreement with the X-ray structure and confirm the phase purity of the prepared sample. The molecular structure of the complex was optimized by density functional theory (DFT) calculation at the B3LYP/LANL2DZ level of theory and the results were compared with experimental ones. For more concise study of structure and spectral aspects of the complex, natural bond orbital (NBO) analysis and time-dependent density functional theory (TD-DFT) have been also performed. Thermal stability of the cadmium iodide complex was investigated by thermogravimetric analysis (TGA). Finally, cadmium oxide nanoparticles was prepared by direct calcination of CdLI2 complex as a new precursor.

    更新日期:2018-11-27
  • Effect of pre-treatments on biological methane potential of dewatered sewage sludge under dry anaerobic digestion
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-26
    Lu Wenjing, Pan Chao, Arun Lama, Fu Xindi, Ye Rong

    The aim of the study is to enhance hydrolysis of dewatered sewage sludge (moisture content 80-83%) to tackle the problem of low biological methane potential (BMP) and low efficiency of dry anaerobic digestion. Different pre-treatment i.e. physical (ultrasonication), chemical (acid, ozone) and combined (ultrasonication-ozone) methods were investigated and evaluated in terms of BMP and biodegradation. Ultrasonic pre-treatment had the best result among the single technologies, the BMP increased by 104.7%, while total solid (TS), volatile solid (VS) and chemical oxygen demand (COD) reduction were improved by 30.1%, 36.9% and 33.9%, respectively, over control. Combined pre-treatment (ultrasonication-ozone) showed more significant enhancement than single methods as evidenced by 138.2% higher BMP and 53.7%, 63.7% and 57.3% more reduction in TS, VS, COD, respectively, over control. The BMP increment positively correlated either with energy input, concentration or dose of pre-treatment applied. Among the tested methods, the physical pre-treatments out-compete chemical ones. Ultrasonic combined with ozone pre-treatment technology has good energy and economic feasibility.

    更新日期:2018-11-27
  • Parametric and phenomenological studies about ultrasound-enhanced biosorption of phenolics from fruit pomace extract by waste yeast
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-24
    Yang Tao, Hongbin Han, Wangxin Liu, Lu Peng, Yue Wang, Shekhar Kadam, Pau Loke Show, Xiaosong Ye

    In this work, sonication (20-kHz) was conducted to assist the biosorption of phenolics from blueberry pomace extracts by brewery waste yeast biomass. The adsorption capacity of yeast increased markedly under ultrasonic fields. After sonication at 394.2 W/L and 40 °C for 120 min, the adsorption capacity was increased by 62.7% compared with that under reciprocating shaking. An artificial neural network was used to model and visualize the effects of different parameters on yeast biosorption capacity. Both biosorption time and acoustic energy density had positive influences on yeast biosorption capacity, whereas no clear influence of temperature on biosorption process was observed. Regarding the mechanism of ultrasound-enhanced biosorption process, the amino and carboxyl groups in yeast were considered to be associated with the yeast biosorption property. Meanwhile, ultrasound promoted the decline of the structure order of yeast cells induced by phenolic uptake. The interactions between yeast cells and phenolics were also affected by the structures of phenolics. Moreover, the mass transfer process was simulated by a surface diffusional model considering the ultrasound-induced yeast cell disruption. The modeling results showed that the external mass transfer coefficient in liquid phase and the surface diffusion coefficient under sonication at 394.2 W/L and 40 oC were 128.5% and 74.3% higher than that under reciprocating shaking, respectively.

    更新日期:2018-11-26
  • Novel approaches based on Hydrodynamic Cavitation for treatment of wastewater containing potassium thiocyanate
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-22
    Rajashree H. Jawale, Parag R. Gogate

    Significant development in the industrial technologies and applications based on the use of cyanide derivatives has also led to significant environmental problems critically needing research in developing new technologies. Present study investigates the use of novel treatment approach of hydrodynamic cavitation (HC) combined with chemical oxidation and catalyst for the degradation of Potassium Thiocyante (KSCN) for the first time. The effect of operating pressure (2-5 bar) and initial pH (2-7.1) on the degradation has been studied initially. Effect of combination of HC with H2O2 (varying KSCN: H2O2 ratios as 1:0.5 to 1:3), HC+O3 (varying ozone mass flow rate over the range of 200 to 400 mg/h), HC+O3+catalyst (TiO2/ZnO/CuO at fixed loading of 0.1 g/L) as process intensifying approaches on the KSCN degradation has been studied. Combination of HC+O3+CuO at different loadings of CuO has also been investigated. Use of combination of HC with H2O2 and HC with Ozone resulted in extent of KSCN degradation as 73% and 71.1% respectively. Among the different combinations of HC+O3+Catalysts (TiO2/ZnO/CuO), HC+O3+CuO (at loading of 0.15 g/l) resulted in highest KSCN degradation as 86.5%. Combination of HC+H2O2+O3+CuO was established to be the best approach yielding complete degradation with synergistic index of 2.98 and 92.9% COD removal. The study also focused on establishing kinetic rate constants which revealed that all the approaches followed first order mechanism with higher rate constants for the combination approaches as compared to individual approach. Overall, it has been conclusively established that hydrodynamic cavitation based combined treatment schemes are very effective for the treatment of biorefractory wastewaters.

    更新日期:2018-11-24
  • Fluorescent Metal-Doped Carbon Dots for Neuronal Manipulations
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-22
    Vijay Bhooshan Kumar, Raj Kumar, Aharon Gedanken, Orit Shefi

    There is a growing need for biocompatible nanocomposites that may efficiently interact with biological tissues through multiple modalities. Carbon dots (CDs) could serve as biocompatible fluorescence nanomaterials for targeted tissue/cell imaging. Important goals toward this end are to enhance the fluorescence quantum yields of the CDs and to increase their targetability to cells. Here, sonochemistry was used to develop a one-pot synthesis of CDs, including metal-doped CDs (M@CDs), demonstrating how various experimental parameters, such as sonication time, temperature, and power of sonication affect the size of the CDs (2–10 nm) and their fluorescence properties. The highest measured quantum yield of emission was ∼16%. Similarly, we synthesized CDs doped with different metals (M@CDs) including Ga, Sn, Zn, Ag, and Au. The interaction of M@CDs with neuron-like cells was examined and showed efficient uptake and low cytotoxicity. Moreover, the influence of the M@CDs on the improvement of neurites during initiation and elongation growth phases were compared with pristine CDs. Our research demonstrates the use of M@CDs for imaging and for neuronal interactions. The M@CD nanocomposites are promising due to their biocompatibility, photo-stability and potential selective affinity, paving the way for multifunctional biomedical applications.

    更新日期:2018-11-24
  • Preparation of low molecular weight heparin using an ultrasound-assisted Fenton-system
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-20
    Zijian Zhi, Junhui Li, Jianle Chen, Shan Li, Huan Cheng, Donghong Liu, Xingqian Ye, Robert J. Linhardt, Shiguo Chen

    Heparin, a high-molecular weight acidic polysaccharide, has raised much interest in the field of biomedical research due to its multiple bio-functions. The anticoagulant application of heparin in routine clinical practice, however, has been limited as the large molecular size of heparin can reduce its subcutaneous bioavailability and lead to severe adverse consequences such as thrombocytopenia. Here, we report a highly efficient and convenient method to depolymerize high-molecular weight, unfractionated heparin (UFH), into low molecular weight heparin (LMWH) by combining physical ultrasonic treatment with the chemical Fenton reaction, referred to as sono-Fenton. We found that this combination treatment synergistically degraded UFH into a LMWH of 4.87 kDa within 20 min. We characterized the mechanism of sono-Fenton heparin degradation through multiple approaches, including HPLC-SAX, disaccharide composition, FT-IR, NMR and top-down analysis, and found that the uronic acid residue in heparin was the most susceptible site attacked by ·OH radicals produced in the sono-Fenton process. Importantly, the LMWH prepared by this method had significantly higher anticoagulant activity than UFH and other LMWHs. This approach represents an effective method to produce heparin with improved activity and should be potentially useful for heparin production in the pharmaceutical industry.

    更新日期:2018-11-21
  • Structural changes caused by ultrasound pretreatment: direct and indirect demonstration in potato cylinders
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-15
    Alberto Claudio Miano, Meliza Lindsay Rojas, Pedro Esteves Duarte Augusto

    This work aimed to demonstrate the internal and external structural changes in potato cylinders caused by different times of ultrasound pretreatment. In addition, the structural changes were associated with the viscoelasticity and mass transfer. For which, potato cylinders were immersed in distilled water and pretreated with and without ultrasound (ultrasonic bath of 91 W/L and 25 kHz) up to 120 min. Then, the microstructure was evaluated by stereoscopic observation as a direct method, and by viscoelasticity and mass transfer evaluation (pigment diffusion and drying) as indirect methods. Both external and internal structure of the material were evaluated. As results, it was demonstrated the formation of microchannels inside the potato tissue as well as the surface erosion caused by ultrasound, especially after 60 min of pretreatment. Further, it was observed that the product viscoelasticity is affected by the ultrasound pretreatment reducing the elasticity. In addition, the mass transfer on the cylinders was improved by ultrasound pretreatment. The pigment transfer was enhanced, demonstrating the acoustic erosion at the sample border. Furthermore, the drying process was accelerated by ultrasound, demonstrating the reduction of the internal resistance to water transfer. Finally, it was observed that high structural changes on the potato cylinders can bring some disadvantages such as changes on the color and severe shrinkage. This work concluded that the structural changes caused by ultrasound can be evidenced directly and indirectly. Furthermore, different structural changes took place, on both inside and outside of the vegetable sample. However, despite ultrasound improves further process, especially those that involve mass transfer, the parameters time and ultrasonic power must be optimized to obtain desirable results without reducing the product quality.

    更新日期:2018-11-16
  • PMS activation using reduced graphene oxide under sonication: Efficient metal-free catalytic system for the degradation of rhodamine B, bisphenol A, and tetracycline
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-13
    Yacine Cherifi, Ahmed Addad, Hervé Vezin, Alexandre Barras, Baghdad Ouddane, Ahcène Chaouchi, Sabine Szunerits, Rabah Boukherroub

    This study addresses the influence of ultrasound irradiation on the activation of peroxymonosulfate (PMS) using reduced graphene oxide (rGO) under metal-free conditions for the catalytic degradation of rhodamine B (RhB), bisphenol A (BPA) and tetracycline (TC). Our results revealed that the combination of PMS/rGO and ultrasonication enhanced significantly the degradation rate, reaching full degradation in relatively short times with total organic carbon (TOC) removal exceeding 85% of the investigated pollutants. In contrast, under these experimental conditions, rGO/ultrasound and PMS/ultrasound achieved less than 20% degradation of the same pollutants. Electron paramagnetic resonance (EPR) studies along with quenching experiments suggested that hydroxyl radicals (•OH) are the dominant reactive species in the degradation process. Furthermore, inductively coupled plasma atomic emission spectroscopy (ICP-AES) and EPR data revealed the presence of trace manganese (Mn) in rGO. To elucidate the role of Mn on the degradation process, rGO was subjected to hot acid treatment for 48 h to remove trace Mn. While the chemical composition of rGO was not significantly altered by this chemical treatment, the degradation efficiency decreased upon Mn dissolution. The result suggests that trace metal in rGO might account for the efficiency of PMS activation. Finally, plausible degradation pathways were proposed based on LC-MS analysis of the reaction intermediates.

    更新日期:2018-11-13
  • Study of encapsulated microbubble cluster based on association schemes perspective
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-13
    S. Behnia, M. Yahyavi, R. Habibpourbisafar, F. Mottaghi

    Ultrasound contrast agents have been recently utilized in therapeutical implementations for targeted delivery of pharmaceutical substances. Radial pulsations of a cluster of encapsulated microbubbles under the action of an ultrasound field are complex and highly nonlinear, particularly for drug and gene delivery applications with high acoustic pressure amplitudes. In this paper, based on Qin-Ferrara’s model (Qin and Ferrara, 2010), the complete synchronization and cluster formation in targeted microbubbles network are studied. Also, association schemes as a novel approach are suggested for finding a relationship between coupled microbubbles elements which are immersed in blood or surrounding soft tissue. A significant advantage of this method is that the stability of the synchronized state (or symmetric eigenmode of mutual bubble oscillation) with respect to another state (another eigenmode) can now predict. More interestingly, we find a significant relationship between an isolated and multiple microbubbles. The results show that the problem of studying the dynamics of encapsulated microbubble cluster at synchronization state is dependent on the dynamical characteristics of isolated cases, shell thickness, density. Also, the distance between microbubbles has an important role in their synchronous modes.

    更新日期:2018-11-13
  • Ultrasonic cavitation erosion mechanism and mathematical model of HVOF sprayed Fe-based amorphous/nanocrystalline coatings
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-09
    Lei Qiao, Yuping Wu, Sheng Hong, Jie Cheng

    A Fe-based amorphous/nanocrystalline coating was prepared on the AISI 321 steel by the high-velocity oxygen-fuel (HVOF) thermal spraying technology in this paper. Cavitation erosion behavior and mechanism of the coating was studied through the analysis of curves for cavitation erosion resistance versus time and the observation of eroded particles, with the AISI 321 steel as a reference. It was found that the Fe-based coating had better cavitation erosion resistance than the AISI 321 steel, and exhibited obvious periodic failure behavior in the cavitation erosion process. Besides, the crystallization of the amorphous phase under the effect of shock wave was observed. The cavitation erosion mathematic model of the coating was also established. The model indicated that the cavitation erosion resistance of the coating was related to the grain size and the fracture energy per unit area of the coating. Small grain size and high fracture energy per unit area were benefit to improve the cavitation erosion resistance of the Fe-based coating.

    更新日期:2018-11-10
  • Effect of geometrical configuration of reactor on a ZrP nano-dispersion process using ultrasonic irradiation
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-09
    Saki Fukunaga, Sayaka Higashi, Takafumi Horie, Hiroaki Sugiyama, Akihisa Kanda, Tong-Yang Hsu, Kuo-Lun Tung, Keita Taniya, Satoru Nishiyama, Naoto Ohmura
    更新日期:2018-11-10
  • Hydrodynamic and mass transfer investigation of oxidative desulfurization of a model fuel using an ultrasound horn reactor
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-09
    Masoud Rahimi, Shahrokh Shahhosseini, Salman Movahedirad

    Ultrasound assisted oxidative desulfurization (UAOD) is a promising technology, which can result in ultra-low sulfur fuels in order to reduce the environmental crisis. Most of the researches have been conducted with the experimental approaches. In the present study, a computational fluid dynamic (CFD) model has been developed to investigate the hydrodynamics as well as the reactions involved in a sonoreactor. The results indicate that the physical and chemical effects associated with the ultrasonic field can contribute to the enhancement of the reaction and sulfur removal rates. However, the physical effects are predominant as compared to the chemical effects. Indeed, homogenous mixing and fine micro-emulsification caused by the physical effects lead to increase the interfacial area and mass transfer rate between the immiscible aqueous and oil phases. The dibenzothiophene concentration predicted by the simulation was in a reasonably good agreement with the corresponding experimental data. Another key hydrodynamic parameter induced by ultrasonic field was turbulent kinetic energy, which can play an important role in the sulfur removal rate. The results indicate the higher desulfurization efficiency has been attained at the regions with the higher velocity fluctuations.

    更新日期:2018-11-10
  • Ultrasonic semi-solid soldering 6061 aluminum alloys joint with Sn-9Zn solder reinforced with nano / nano+ micron Al2O3 particles
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-09
    Ding Min

    In this study, the joint at low temperature with nano-Al2O3 particles and Al2O3 nano+micro particles were fabricated by semisolid assisted ultrasonic vibration with nano-Al2O3 particle of 50 nm and volume fractions of 1% and micron-Al2O3 particle of 10 μm and volume fractions of 1%. The joints were examined in order to understand the effects of Al2O3 additions as microstructure, interface morphology and shear strength as well as mechanical properties of soldering 6061 aluminum alloys. Due to different size, the scallop-shaped solid solution layer was changed into a groove layer, and its thickness of Al3Zn2 solid solution layer was decreased. The grain refinement mechanism of Sn-9Zn-1nmAl2O3 is mainly sono-crystallization (enhanced nucleation). However, the grain refinement mechanisms of Sn-9Zn-1nm1μm Al2O3 change to be mainly sono-crystallization+ sono-fragmentation. With the increase of different size particles, the fracture mode transforms from brittleness to ductile fracture and finally to dimple structure. Micro particles may contribute less to the strength compared to the refining effect, but significantly improve the plasticity.

    更新日期:2018-11-10
  • Metal Organic Frameworks (MOFs) and ultrasound: A review
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-09
    Christos Vaitsis, Georgia Sourkouni, Christos Argirusis

    Metal-organic frameworks (MOFs) have received a lot of attention due to their unique properties and abundant functionalities. Permanent porosity and high surface area are just a few traits that have made them attractive to researchers. They can be prepared as task-specific materials by exploiting the functional group variety and tuning their size and geometry. The main purpose of this review is to present an alternative method of preparing MOF crystals and underline the advantages of ultrasound assisted (sonochemical) synthesis. State of the art ultrasound assisted techniques for the preparation of MOFs in nanoscale are presented. Optimization of morphology and particle size is highlighted throughout this work, as we discuss the effects of various factors, such as energy input, reagent concentration, adequate solvents, reaction time and more.

    更新日期:2018-11-09
  • Ultrasonic Nano-Emulsification - A Review
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-09
    Seyed Mohammad Mohsen Modarres Gheisari, Roghayeh Gavagsaz-Ghoachani, Massoud Malaki, Pedram Safarpour, Majid Zandi

    The emulsions with nano-sized dispersed phase is called nanoemulsions having a wide variety of applications ranging from food, dairy, pharmaceutics to paint and oil industries. As one of the high energy consumer methods, ultrasonic emulsification (UE) are being utilized in many processes providing unique benefits and advantages. In the present review, ultrasonic nano-emulsification is critically reviewed and assessed by focusing on the main parameters such pre-emulsion processes, multi-frequency or multi-step irradiations and also surfactant-free parameters. Furthermore, categorizing aposematic data of experimental researches such as frequency, irradiation power and time, oil phase and surfactant concentration and also droplet size and stability duration are analyzed and conceded in tables being beneficial to indicate uncovered fields. It is believed that the UE with optimized parameters and stimulated conditions is a developing method with various advantages.

    更新日期:2018-11-09
  • Ultrasonic degradation of diaminobenzidine in aqueous medium
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-07
    Kwedi Nsah Louis Marly, Takaomi Kobayashi

    By using 500 kHz high frequency ultrasound (US), 3,3’-diaminobenzidine (DAB) was treated at pH 2 under air atmosphere. The US effect of DAB absorption at 280 nm was composed at 43 and 141 kHz for the detection of fluorescence. When 100 W of US power was used, the DAB absorption band decreased with exposure time. It was noted that, a new absorption broad band at 350 nm – 500 nm appeared only under 141 and 500 kHz. Also, fluorescence spectra of the treated DAB were measured when excited at 370 nm. Increasing US exposure time resulted to a broad emission band at 478 nm, indicating that 1H,1’H-5,5’-Bibenzotriazole (BBT) was produced by US exposure at 500 kHz. This product was confirmed by NMR spectroscopy to be a triazine ring formed from NH2 proton in DAB, due to the formation of nitrite ions in the US aqueous medium at 500 kHz. Hence, DAB was degraded while BBT was formed.

    更新日期:2018-11-07
  • Ultrasound Assisted Preparation, Characterization and Adsorption Study of Ternary Chitosan-ZnO-TiO2 Nanocomposite: Advantage over conventional method
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-07
    B.A. Bhanvase, A. Veer, S.R. Shirsath, S.H. Sonawane

    In the present work, the synthesis of ternary chitosan/zinc oxide/titanium dioxide (CTS-ZnO-TiO2) nanocomposite was carried out with the use of mechanical stirring (conventional) and ultrasound assisted method. The characterization of prepared CTS-ZnO-TiO2adsorbent was carried out using XRD, TEM, FTIR and the results of these analysis methods proved the successful preparation of ternary nanocomposite. Crystal violet (CV) dye was used as a pollutant to observe the adsorption ability of the prepared nanocomposite and the nanocomposite prepared by ultrasonic-assisted method proved to be a better adsorbent. The CV dye adsorption was significant forCTS-ZnO-TiO2 nanocomposite synthesized with the use of ultrasound assisted method compared to that prepared by conventional method. It is due to the physical effects of the ultrasonic irradiations due to which formation of finely dispersed nanocomposite takes place than that by conventional method. For batch adsorption the effect of various operating parameters such as initial dye concentration, time, temperature and adsorbent dose has been evaluated. The obtained data were processed using isotherm models, adsorption kinetics and the thermodynamic behavior of the cationic dye adsorption was also studied. The isotherm data was correlated reasonably well by the Temkin adsorption isotherm. Pseudo-second-order kinetic model provided a better correlation for the experimental data compared to pseudo first order, Elovich model and power function kinetics model. Thermodynamic parameters for adsorption indicated that the dye adsorption was spontaneous and endothermic in nature.

    更新日期:2018-11-07
  • High-sensitivity Detection of Nitroaromatic Compounds (NACs) by the pillared-layer metal- organic framework synthesized via ultrasonic method
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-11-05
    Azar Hakimifar, Ali Morsali

    Nanorods of zinc(II) based metal-organic framework (MOF) were prepared via ultrasonic method without any surfactants at room temperature and atmospheric pressure. Control of particle size and morphology was enhanced in this synthesis method. Nanorods of pillared-layer metal organic framework, [Zn2(ubl)2(bipy)]·DMF (TMU-18), where ubl (urea-based ligand) is 4,4'-carbonylbis(azanediyl)dibenzoic acid, 4,4'-Bipyridine (bipy) DMF = N,N-dimethyl formamide), was synthesized under ultrasound irradiation in different concentrations of initial precursor. The nano structure and morphology of the synthesized MOF were characterized by Field Emission Scanning Electron Microscopy (FE-SEM), powder X-ray diffraction, elemental analysis and FT-IR spectroscopy. Moreover, Fluorescence emissions of nanorods have been studied. Luminescent MOFs (LMOFs) have shown great potential as sensor for various nitro explosives by modulating the luminescence behavior in presence of nitro explosives. Urea-functionalized MOF shows high selectivity for sensing of the nitro explosive 2,4,6-trinitrophenol (TNP) even in the presence of other nitroaromatic compounds in methanol solution. Fluorescence intensity decreased with increasing contents of nitroaromatics in organic solution due to fluorescence quenching effect. The ultrasound method has some advantages such as short duration time of reaction, no need to high temperatures and pressures for synthesis nano-materials and low costs in comparison to other methods. Considering these advantages we used ultrasonic method to produce these nanorods which show high sensitivity in detecting nitroaromatics.

    更新日期:2018-11-05
  • 更新日期:2018-11-05
  • Cavitation Inception of Water with Solid Nanoparticles: A Molecular Dynamics Study
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-30
    Buxuan Li, Youwei Gu, Min Chen

    Cavitation in liquid with impurities is important in heterogeneous nucleation applications. One of the most widely existing kinds of impurities is solid particles, which can be found in natural water from rivers and specially prepared water such as nanofluids. Understanding the effects caused by the existence of nanoparticles on cavitation in water is vital to many applications because of the rapid development of nanotechnologies and biology. In this study, cavitation in water with nanoparticles is investigated through molecular dynamics simulations. The effects by different particle materials and size on cavitation are discussed by using SiO2 and polyethylene nanoparticles and by adjusting spherical particle diameters. The nucleation rate and the formation of critical bubbles in cavitation are studied via the Voronoi tessellation and the mean first passage time methods. The hydrogen bond network in water is also analyzed. Results reveal that the critical bubble radius has little difference in different simulation configurations. With the same particle size, cavitation in water with polyethylene nanoparticles is promoted to a greater extent than that with SiO2 nanoparticles. With the same nanoparticle material, cavitation is promoted with the increase in particle size in a range spanning half to ten times the critical bubble radius. Beyond this range, particle size has little influence on cavitation. Possible reasons for those effects on cavitation due to the presence of solid nanoparticles are discussed by calculating the variation in the average number and average energy of hydrogen bonds in water.

    更新日期:2018-10-31
  • Experimental Study on Inlet Turbulent Flow under Ultrasonic Vibration: Pressure Drop and Heat Transfer Enhancement
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-25
    A. Amiri Delouei, H. Sajjadi, R. Mohebbi, M. Izadi

    This experimental study examines the impact of ultrasonic vibration on pressure drop and heat transfer enhancement of inlet turbulent flows. A stainless steel tube connected to an ultrasonic transducer and immersed in a constant temperature two-phase fluid was considered as the test section. Regarding the designed configuration, the ultrasonic transducer utilized had an acoustic frequency of 28 kHz and two different power levels of 75 W and 100 W. The experiments were conducted for different ultrasonic power levels, inlet temperatures, and flow rates. The accuracy of measurements was successfully validated via the existing empirical correlations. The results indicate that the effect of ultrasonic vibration on pressure drop and heat transfer enhancement diminishes with the growth of both Reynolds number and inlet temperature. Based on previously reported results on inlet flows with a laminar flow regime, the effect of ultrasonic vibration is very trivial in current turbulent inlet flows (up to 7.28% for heat convection enhancement). The results of the present study will be beneficial for future investigations on designing vibrating heat exchangers.

    更新日期:2018-10-26
  • Mechanism of Improving the Rate of Sono-oxidation of a KI Solution by Introduction of CO2 into an Ar Atmosphere
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-26
    Yuki Ono, Kiyoaki Shinashi, Hisashi Tanaka, Hisashi Harada

    The rate of sono-oxidation of KI increased in a CO2-Ar system compared to Ar alone. Higher values were obtained at 200 kHz with a maximum ratio of about forty. To determine the role of additional CO2 in the system, the effect of the pH of the reactant solution, the additional effect of NaHCO3, sonoluminescence, and an analysis of products were examined. It appeared that the pH was not a significant contributor to the acceleration of sono-oxidation activity although the rate depended on the pH. On the other hand, in spite of the alkaline solution, the reaction rate in NaHCO3-KI solution was higher than that in the solution without NaHCO3. This behavior was similar to the case of introduction of CO2, implying the possible evolution of CO2 from NaHCO3. Our data suggested that CO2 reacted with H radicals, which were produced together with OH radicals during sonication and a considerable amount of OH radicals remained. Because OH radicals have strong oxidative power, the level of sono-oxidation activity increases.

    更新日期:2018-10-26
  • Mineralization of dinitrotoluenes in aqueous solution by sono-activated persulfate enhanced with electrolytes
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-26
    Wen-Shing Chen, Chi-Pin Huang

    Oxidative degradation of dinitrotoluenes (DNTs) in industrial wastewater was conducted by sono-activated persulfate process assisted with electrolytes. Experiments were carried out to elucidate the influence of various operating parameters on the sonolytic behavior, such as species and concentrations of electrolytes, ultrasonic power intensity, reaction temperature, dosage of oxygen and persulfate anions. The outcomes indicate that sulfate radicals serve as main oxidants in the sono-activated persulfate process, wherein MgSO4 electrolyte obviously inhibits microbubble coalescence, leading to enhancement of cavitation strength and DNTs removal percentage. On addition of electrolytes, the increment of DNTs removal percentages was proportional to ionic strength of electrolytes. According to the results obtained from gas chromatograph-mass spectrometer (GC-MS), it is postulated that DNTs initially undergo denitration pathway with cleavage of nitro group into o-mononitrotoluene (MNT) or oxidation of methyl group followed with decarboxylation procedure into 1,3-dinitrobenzene (DNB), respectively. Due to electrolytes observed commonly in wastewater, the sono-activated persulfate process coupled with electrolytes is potentially applied to dispose wastewater effluent from toluene nitration processes.

    更新日期:2018-10-26
  • Noble metal NPs and nanoalloys by sonochemistry directly processed on nanocarbon and TiN substrates from aqueous solutions
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-26
    Ayoub Laghrissi, Claus-Henning Solterbeck, Dimitri Schopf, Mohammed Es-Souni
    更新日期:2018-10-26
  • Facile photo-ultrasonic assisted reduction for preparation of rGO/Ag2CO3 nanocomposites with enhanced photocatalytic oxidation activity for tetracycline
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-25
    Abulajiang Reheman, Kuerbangnisha Kadeer, Kenji Okitsu, Maimaiti Halidan, Yalkunjan Tursun, Talifu Dilinuer, Abulizi Abulikemu

    Various antibiotics in the aquatic systems have threat the aquatic ecosystem balance and the human health. In this study, a degradation treatment method for tetracycline (TC), one of the commonly used antibiotics, was explored by using novel photocatalysts of rGO/Ag2CO3 under simulated sunlight, because conventional treatment methods are not efficient on the removal of TC. rGO/Ag2CO3 nanocomposites were synthesized via a facile photo-ultrasonic assisted reduction method. More than 90% of TC was removed by 1 % (weightrGO/weightcomposites) rGO/Ag2CO3 within 60 min at pH= 4, which was about 1.3 times higher than that of pure Ag2CO3. The cycling experiments indicated that 1 % rGO/Ag2CO3 was highly stable and could be reused for at least 5 cycles without significant deactivation to its photocatalytic activity. In addition, the effects of pH, temperature, and dosage amount of 1 % rGO/Ag2CO3 on photocatalytic degradation were investigated. Meanwhile, the effect of ultrasonic on the degradation of TC was also investigated. This study can provide a new method for the preparation of smaller nanosized materials and photocatalysts with high activity and stability for its environmental or other applications.

    更新日期:2018-10-25
  • On the mechanism of dendritic fragmentation by ultrasound induced cavitation
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-25
    S. Wang, Z. Guo, X.P. Zhang, A. Zhang, J.W. Kang

    A dedicated solidification device and high speed camera were used to capture dendritic fragmentation of pure succinonitrile (SCN) induced by oscillating ultrasonic bubbles. Theoretical analysis of the melting behavior of the dendrite was performed based on local solidification thermodynamics. The dendritic growth or the evolution of the solid-liquid interface is closely related to both thermodynamics of the cavitation bubble and the local geometry of the dendrite. Accordingly, for the first time, a dimensionless scaling formulation was developed by fitting both theoretical and experimental data to determine the variational pressure exerted by the cavitation bubble.

    更新日期:2018-10-25
  • Conformational and physicochemical properties of quinoa proteins affected by different conditions of high-intensity ultrasound treatments
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-24
    A. Vera, M.A. Valenzuela, M. Yazdani-Pedram, C. Tapia, L. Abugoch

    Quinoa proteins (QP) have promise as a potential source of novel food ingredients, and it is of great interest to know how high-intensity ultrasound (HIUS) treatments affect the properties of QP. This work aimed to study the impact of on-off time-pulses of HIUS treatments on the structural and physicochemical properties of QP; samples were treated at 5, 10, 20, and 30 min with on-off pulses of 10 s/10 s, 5 s/1 s, and 1 s/5 s). Structural changes were evaluated using PAGE-SDS, circular dichroism, fluorescence spectroscopy, and differential scanning calorimetry. Meanwhile, physicochemical properties were also examined, including solubility, Z-average, polydispersity index PDI, and Z-potential. PAGE-SDS showed the appearance of polypeptides over 190 kDa in HIUS samples-treated. All samples presented 15.6% α-helices, 31.3% β-sheets, 21.8% β-rotations, and 31.4% random coils independent of the HIUS treatment. β-turn structures and “random coils” were not affected by HIUS. When US 10 s/10 s and 1 s/5 s were applied, an increase in the % α-helix and a decrease in β-fold were observed, which could indicate a small conversion of β-folds to α-helices. Fluorescence spectra for all HIUS showed a significant increase (23%) of average fluorescence intensity and a decrease of λmax in relation to that of the control (346 dnm and 340 nm average HIUS treatment). DSC showed one endotherm in all cases (81.6 to 99.8 °C), and an increase in Td was observed due to the effect of the HIUS treatment. HIUS caused a 48% increase in solubility. The Z-average of the HIUS samples compared to that of the controls showed an increase from 37.8 to 47.3 nm. PDI and Z-potential values from the QP controls and the HIUS samples did not show significance differences and presented average values of 0.466±0.021 (PDI) and -16.63±0.89 (Z-potential). It is possible to conclude that HIUS treatments affect the secondary and tertiary structure of quinoa proteins, and these changes resulted in an increase of solubility and particle size. HIUS treatment as a new and promising technology that can improve the QP solubility properties and in that way allow its use as an ingredient with a good source of protein to develop different types of beverages / protein sauces.

    更新日期:2018-10-24
  • Assessment of a low-frequency ultrasound device on prevention of biofilm formation and carbonate deposition in drinking water systems
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-22
    Laurence Mathieu, Anaïs Keraval, Nico F. Declercq, Jean-Claude Block

    A device generating low-frequency and low-intensity ultrasound waves was used for mitigating biofilm accumulation and scaling. Two systems were tested: a lab-scale plate heat exchanger operated with continuously recycled water and a continually fed flow-through drinking water pilot used for mimicking water circulation in pipes. Initial deposition of bacterial cells was not prevented by ultrasound wave treatment. However, whatever the tested system, both further calcium carbonate deposition and biofilm growth were markedly inhibited. Biofilms formed in reactors subjected to low-frequency and low-intensity ultrasound waves were weakly attached to the material. Even though the activity of bacteria was affected as shown by their lower cultivability, membrane permeability did not appear compromised. Ultrasound technology sounds very promising in both the mitigation of drinking water biofilm and carbonate accumulations.

    更新日期:2018-10-23
  • Effects of Sonication on Photocatalytic Reforming of Aqueous Glycerol Solution
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-22
    Y. Mizukoshi

    Large amount of glycerol has been generated as a byproduct in the synthesis of biodiesel fuel and their effective utilization ways have been explored. Addition of glycerol effectively enhanced photocatalytic H2 evolution from aqueous solution dispersing TiO2 photocatalyst nanoparticles. The deuterium labeled experiments clarified that noticeable amount of hydrogen atoms are supplied from glycerol molecules. H2 and CO2 were mainly evolved under UV illumination. On the other hand, sonication to the UV-illuminated system enhanced the CO evolution and the amount of the evolved CO depended upon the intensity of the ultrasound. Sonochemical modulation of H2/CO ratio is a promising approach to produce syngas, which is an important raw material in C1 chemistry.

    更新日期:2018-10-22
  • 更新日期:2018-10-22
  • Ultrasound processing of fresh and frozen semi-skimmed sheep milk and its effects on microbiological and physical-chemical quality
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-19
    Celso F. Balthazar, Antonella Santillo, Jonas T. Guimarães, Vitoantônio. Bevilacqua, Maria Rosario Corbo, Mariangela Caroprese, Rosaria Marino, Erick A. Esmerino, Marcia Cristina Silva, Renata S.L. Raices, Mônica Q. Freitas, Adriano G. Cruz, Marzia Albenzio

    The objective of this study was to evaluate the effect of ultrasound treatment on the microbiological quality, protein and free amino acid profiles of fresh and frozen stored semi-skimmed sheep milk. Milk was treated as fresh or frozen and stored up to one, three and six months. Output power time and pulse time were the parameters combined to design four different ultrasound (US) treatments: power 78 W and duration 6 min (US1); power 78 W and duration 8 min (US2); power 104 W and duration 4 min (US3) power 104 W and duration 6 min (US4). Pulse duration was of 4 seconds for each treatment. Sample US1 was discarded due to non effectiveness of US treatment, while other samples showed interesting results. Also, it was verified a frost effect on microorganisms in all samples which were frozen before treatment. No relevant change was reported on amino acid profile. The study showed promising results: the ultrasound treatment inactivated or eliminated the studied contaminant bacteria in semi-skimmed sheep milk, while maintained acceptable amount of lactic bacteria, which could be advantageous for dairy products processing.

    更新日期:2018-10-22
  • 更新日期:2018-10-22
  • Mechanism of ultrasonic impregnation on porosity of activated carbons in non-cavitation and cavitation regimes
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-19
    Zongbo Zhang, Xiaoyang Liu, Dawei Li, Yuqi Lei, Tiantian Gao, Baogui Wu, Jiawei Zhao, Yankui Wang, Guangyan Zhou, Huimin Yao

    Ultrasonic impregnation has proven to be an effective method to improve surface area and pore volume during preparation of activated carbons. However, the mechanism by which the promotion effect of ultrasonic impregnation is still ambiguous. Fundamental wave pressure (FWP) and broadband integrated pressure (BIP) were used to estimate the non-cavitation (vibration) energy and cavitation energy, respectively. The effects of FWP and BIP on the pore volume, surface area, surface functional groups, and microcosmic morphology were investigated in non-cavitation and cavitation regimes. Ultrasonic vibration promoted the surface enlargement and pore development of activated carbons, and it mainly affected the development of mesopore volume (Vmes) in both the pore volume and the mesopore-size-distribution range. The Vmes was enhanced by 60%-100% in the non-cavitation regime. Ultrasonic cavitation also facilitated porosity development of activated carbons, and it mainly affected the development of specific surface area (SBET) and micropore volume (Vmic). The excessive cavitation led to a decrease of the porosity of activated carbons, so the BIP should be optimized during impregnation. The highest SBET, Vmic, and Vmes for activated carbons were obtained by in the presence of both FWP and BIP, which were enhanced by 29.05%, 30.23%, and 113.33%, respectively, compared with the corresponding value for the activated carbon prepared without using ultrasonic impregnation. This work provided new insight into the role of the acoustic energy present during impregnation in tuning properties of activated carbons.

    更新日期:2018-10-22
  • Enhancement of ultrasound-assisted degradation of Eosin B in the presence of nanoparticles of ZnO as sonocatalyst
    Ultrason. Sonochem. (IF 6.012) Pub Date : 2018-10-19
    Reza Mahdavi, S. Siamak Ashraf Talesh

    In this research, ZnO nanoparticles, as a sonocatalyst for degradation of Eosin B dye under ultrasonic irradiation, were synthesized. Various experimental conditions (ultrasound irradiation power: 50-250 W, ultrasound irradiation time: 10-70 min, catalyst dosage: 1-3 g/L and initial dye concentration: 5-25 mg/L), using ZnO nanoparticles were investigated in order to find the optimal condition for the degradation of Eosin B. The crystalline and grain size of samples were obtained using X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), 15 and 30 nm, respectively. The nanoparticles structure was observed in the form of hexagonal. The band-gap of the prepared nanoparticles was measured as 2.9 eV which is appropriate for sonodegradation process under ultrasonic irradiation. Results demonstrated that Eosin B degradation efficiency was enhanced considerably in sonicated samples compared to non-sonicated ones. The experiments were analyzed via response surface methodology (RSM) based on central composite design (CCD). Analysis of variance (ANOVA) confirmed a good reliability of quadratic response surface model for predicting the sonocatalitic efficiency at various operational parameters (R2 = 0.9918 and Adjusted R2 = 0.9841). Results indicated that increasing the ultrasound power and time led to enhancement of Eosin B removal efficiency, while increasing the dye concentration caused to its decreasing. The degradation of dye, increased by enhancement of the catalyst dosage, where in the specified value (2.17 g/L) it began to decrease. The optimization of the process showed the maximum sonocatalyst degradation of 93.46% at irradiation power, irradiation time, catalyst dosage and dye concentration of 250 W, 70 min, 2.17 g/L and 5.08 mg/L, respectively. Kinetic studies showed that the sonodegradation of Eosin B corresponds well to first-order reaction.

    更新日期:2018-10-22
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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