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  • Degradation of organic wastewater by hydrodynamic cavitation combined with acoustic cavitation
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-11
    Chunhai Yi, Qianqian Lu, Yun Wang, Yixuan Wang, Bolun Yang

    In this paper, the decomposition of Rhodamine B (RhB) by hydrodynamic cavitation (HC), acoustic cavitation (AC) and the combination of these individual methods (HAC) have been investigated. The degradation of 20 L RhB aqueous solution was carried out in a self-designed HAC reactor, where hydrodynamic cavitation and acoustic cavitation could take place in the same space simultaneously. The effects of initial concentration, inlet pressure, solution temperature and ultrasonic power were studied and discussed. Obvious synergies were found in the HAC process. The combined method achieved the best conversion, and the synergistic effect in HAC was even up to 119% with the ultrasonic power of 220 W in a treatment time of 30 min. The time-independent synergistic factor based on rate constant was introduced and the maximum value reached 40% in the HAC system. Besides, the hybrid HAC method showed great superiority in energy efficiency at lower ultrasonic power (88-176 W). Therefore, HAC technology can be visualized as a promising method for wastewater treatment with good scale-up possibilities.

    更新日期:2018-01-11
  • Applications of Ultrasound to Chiral Crystallization, Resolution and Deracemization
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-11
    Christos Xiouras, Antonios Fytopoulos, Jeroen Jordens, Andreas G. Boudouvis, Tom Van Gerven, Georgios D. Stefanidis

    Industrial synthesis of enantiopure compounds is nowadays heavily based on the separation of racemates through crystallization processes. Although the application of ultrasound in solution crystallization processes (sonocrystallization) has become a promising emerging technology, offering several benefits (e.g. reduction of the induction time and narrowing of the metastable zone width, control over the product size, shape and polymorphic modification), little attention has been paid so far to the effects of ultrasound on chiral crystallization processes. Several recent studies have reported on the application of acoustic energy to crystallization processes that separate enantiomers, ranging from classical (diastereomeric) resolution and preferential crystallization to new and emerging processes such as attrition-enhanced deracemization (Viedma ripening). A variety of interesting effects have been observed, which include among others, enhanced crystallization yield with higher enantiomeric purity crystals, spontaneous mirror symmetry breaking crystallization, formation of metastable conglomerate crystals and enhanced deracemization rates. The objective of this review is to provide an overview of the effects of ultrasound on chiral crystallization and outline several aspects of interest in this emerging field.

    更新日期:2018-01-11
  • Performance characterisation of a passive cavitation detector optimised for subharmonic periodic shock waves from acoustic cavitation in MHz and sub-MHz ultrasound
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-10
    Kristoffer Johansen, Jae Hee Song, Paul Prentice

    We describe the design, construction and characterisation of a broadband passive cavitation detector, with the specific aim of detecting low frequency component periodic shock waves with high sensitivity. A finite element model is used to guide selection of matching and backing layers for the shock wave passive cavitation detector (swPCD), and the performance is evaluated against a commercially available device. Validation of the model, and characterisation of the swPCD is achieved through experimental detection of laser-plasma bubble collapse shock waves. The final swPCD design is 20 dB more sensitive to the subharmonic component, from acoustic cavitation driven at 220 kHz, than the comparable commercial device. This work may be significant for monitoring cavitation in medical applications, where sensitive detection is critical, and higher frequencies are more readily absorbed by tissue.

    更新日期:2018-01-11
  • Dynamic behaviour of a two-microbubble system under ultrasonic wave excitation
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-10
    Xiao Huang, Qian-Xi Wang, A-Man Zhang, Jian Su

    Acoustic bubbles have wide and important applications in ultrasonic cleaning, sonochemistry and medical ultrasonics. A two-microbubble system (TMS) under ultrasonic wave excitation is explored in the present study, by using the boundary element method (BEM) based on the potential flow theory. A parametric study of the behaviour of a TMS has been carried out in terms of the amplitude and direction of ultrasound as well as the sizes and separation distance of the two bubbles. Three regimes of the dynamic behaviour of the TMS have been identified in terms of the pressure amplitude of the ultrasonic wave. When subject to a strong wave with the pressure amplitude of 1atm or larger, the two microbubbles become non-spherical during the first cycle of oscillation, with two counter liquid jets formed. When subject to a weak wave with the pressure amplitude of less than 0.5atm, two microbubbles may be attracted, repelled, or translate along the wave direction with periodic stable separation distance, depending on their size ratio. However, for the TMS under moderate waves, bubbles undergo both non-spherical oscillation and translation as well as liquid jet rebounding.

    更新日期:2018-01-11
  • Synthesis, characterization and sonocatalytic applications of nano-structured carbon based TiO2 catalysts
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-09
    Jongbok Choi, Mingcan Cui, Yonghyeon Lee, Jeonggwan Kim, Yeomin Yoon, Min Jang, Jeehyeong Khim

    In order to enhance sonocatalytic oxidation of a recalcitrant organic pollutant, rhodamine B (RhB), it is necessary to study the fundamental aspects of sonocatalysis. In this study, TiO2-incorporated nano-structured carbon (i.e., carbon nanotubes (CNTs) or graphene (GR)) composites were synthesized by coating TiO2 on CNTs or GR of different mass percentages (0.5, 1, 5, and 10 wt%) by a facile hydrothermal method. The sonocatalytic degradation rates of RhB were examined for the effect of ultrasound (US) frequency and calcination temperature by using the prepared TiO2-NSC composites. Since US frequency affected the sonoluminescence (SL) intensities, it was proposed that there exists a correlation between the surface area or band-gap of the sonocatalysts and the degradation kinetic constants of RhB. In addition, the reusability of TiO2-GR composites was also investigated. Overall, the performance of TiO2-GRs prepared by the hydrothermal method was better than that of calcined TiO2-CNTs. Among TiO2-GRs, 5% GR incorporated media (TiO2-GR-5) showed the best performance. Interestingly, the kinetic constants of sonocatalysts prepared under hydrothermal conditions had a negative linear relationship with the band-gap energy for the corresponding media. Furthermore, the strongest SL intensity and highest degradation rates of RhB for both carbonaceous composites were observed at 500 kHz. The kinetic constants of calcined media decreased linearly as the specific area of the media decreased, while the band-gap energy could not be correlated with the kinetic constants. The GR combined TiO2 composite might be a good sonocatalyst in wastewater treatment using ultrasound-based oxidation because of its high stability.

    更新日期:2018-01-09
  • Improving the property of calcium ferrite using a sonochemical method
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-06
    Ruirui Wei, Xuewei Lv, Mingrui Yang, Jian Xu, Zhixiong You

    Power ultrasonic vibration was applied to the solidification of calcium ferrite (CF) melt in this study. The results indicated that power ultrasound can promote the formation of CF by accelerating the solidification process. Ultrasonic vibration greatly refined the CF grains, resulting the grain size decreased from 1893 to 437 μm. Meanwhile, ultrasonic vibration significantly enhanced the compressive strength, reduced the reduction time and improved the reducibility of CF slags. With ultrasonic treatment, the ultimate compressive strength of samples increased from 37.5 to 67.8 MPa, and the reduction time decreased from 225 to 136 min.

    更新日期:2018-01-06
  • Cd2SiO4/Graphene nanocomposite: ultrasonic assisted synthesis, characterization and electrochemical hydrogen storage application
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-06
    Maryam Masjedi-Arani, Masoud Salavati-Niasari

    For the first time, a simple and rapid sonochemical technique for preparing of pure Cd2SiO4 nanostructures has been developed in presence of various surfactants of SDS, CTAB and PVP. Uniform and fine Cd2SiO4 nanoparticle was synthesized using of polymeric PVP surfactant and ultrasonic irradiation. The optimized cadmium silicate nanostructures added to graphene sheets and Cd2SiO4/Graphene nanocomposite synthesized through pre-graphenization. Hydrogen storage capacity performances of Cd2SiO4 nanoparticle and Cd2SiO4/Graphene nanocomposite were compared. Obtained results represent that Cd2SiO4/Graphene nanocomposites have higher hydrogen storage capacity than Cd2SiO4 nanoparticles. Cd2SiO4/Graphene nanocomposites and Cd2SiO4 nanoparticles show hydrogen storage capacity of 3300 and 1300 mAh/g, respectively.

    更新日期:2018-01-06
  • Ultrasound-assisted synthesis of YbVO4 nanostructure and YbVO4/CuWO4 nanocomposites for enhanced photocatalytic degradation of organic dyes under visible light
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-05
    Mohammad Eghbali-Arani, Ali Sobhani-Nasab, Mehdi Rahimi-Nasrabadi, Farhad Ahmadi, Saeid Pourmasoud
    更新日期:2018-01-06
  • Comparisons of spark-charge bubble dynamics near the elastic and rigid boundaries
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-05
    Xiaojian Ma, Biao Huang, Xin Zhao, Yue Wang, Qing Chang, Sicong Qiu, Xiaoying Fu, Guoyu Wang

    The objective of this paper is to apply experimental methods to investigate the dynamics of spark-induced bubbles in the vicinity of the elastic and rigid boundary. In the experiment, the temporal evolution of the bubble is recorded by the high-speed camera at the 25, 000 frames per second, as well as corresponding data such as normalized collapse position, the time of bubble collapse, and the velocity of the high-speed liquid jet. Results are presented for a single bubble generated over the elastic and rigid plates, under a wide range of normalized standoff distance from 0.5 to 3.0. The results show that the high-speed jet emitted by non-spherical bubble collapse near the boundary is one of the important factors to cause the destructive erosion pit. With the increase of the standoff distance, the expansion, shrink, jet formation, and rebound of the bubbles vary evidently adjacent to the different boundary conditions. Compared with the rigid boundary cases, the normalized first collapsed position and the time of bubble collapse are much smaller near the elastic boundary. The formation of the high-speed liquid jet in the neighborhood of the elastic/rigid boundary is founded in two different mechanisms. Furthermore, the normalized maximum velocity near the rigid plate is always larger than that near the elastic plate.

    更新日期:2018-01-06
  • Controlled positioning of microbubbles and induced cavitation using a dual-frequency transducer and microfiber adhesion techniques
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-05
    Alex H. Wrede, Aarthy Shah, Marilyn C. McNamara, Reza Montazami, Nicole N. Hashemi

    We report a study on two methods that enable spatial control and induced cavitation on targeted microbubbles (MBs). Cavitation is known to be present in many situations throughout nature. This phenomena has been proven to have the energy to erode alloys, like steel, in propellers and turbines. It is recently theorized that cavitation occurs inside the skull during a traumatic-brain injury (TBI) situation. Controlled cavitation methods could help better understand TBIs and explain how neurons respond at moments of trauma. Both of our approaches involve an ultrasonic transducer and bio-compatible Polycaprolactone (PCL) microfibers. These methods are reproducible as well as affordable, providing more control and efficiency compared to previous techniques found in literature. We specifically model three-dimensional spatial control of individual MBs using a 1.6 MHz transducer. Using a 100 kHz transducer, we also illustrate induced cavitation on an individual MB that is adhered to the surface of a PCL microfiber. The goal of future studies will involve characterization of neuronal response to cavitation and seek to unmask its linkage with TBIs.

    更新日期:2018-01-05
  • Observation of chemiluminescence induced by hydrodynamic cavitation in microchannels.
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-04
    D. Podbevsek, D. Colombet, G. Ledoux, F. Ayela

    We have performed hydrodynamic cavitation experiments with an aqueous luminol solution as the working fluid. Light emission, together with the high frequency noise which characterizes cavitation, was emitted by the two-phase flow, whereas no light emission from luminol was recorded in the single phase liquid flow. Light emission occurs downstream transparent microdiaphragms. The maximum level of the recorded signal was around 180 photons per second with flow rates of 380 µl/s, that corresponds to a real order of magnitude of the chemiluminescence of 75000 photons per second. The yield of emitted photons increases linearly with the pressure drop, which is proportional to the square of the total flow rate. Chemiluminescence of luminol is a direct and a quantitative demonstration of the presence of OH hydroxyl radicals created by hydrodynamic cavitation. The presented method could be a key to optimize channel geometry for processes where radical production is essential.

    更新日期:2018-01-04
  • Preparation of polyvinyl alcohol graphene oxide phosphonate film and research of thermal stability and mechanical properties
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-02
    Jihui Li, Yunna Song, Zheng Ma, Ning Li, Shuai Niu, Yongshen Li

    In this article, flake graphite, nitric acid, peroxyacetic acid and phosphoric acid are used to prepare graphene oxide phosphonic and phosphinic acids (GOPAs), and GOPAs and polyvinyl alcohol (PVA) are used to synthesize polyvinyl alcohol graphene oxide phosphonate and phosphinate (PVAGOPs) in the case of faint acidity and ultrasound irradiation, and PVAGOPs are used to fabricate PVAGOPs film, and the structure and morphology of GOPAs, PVAGOPs and PVAGOPs film are characterized, and the thermal stability and mechanical properties of PVAGOPs film are investigated. Based on these, it has been proved that GOPAs consist of graphene oxide phosphonic acid and graphene oxide phosphinic acid, and there are C-P covalent bonds between them, and PVAGOPs are composed of GOPAs and PVA, and there are six-member lactone rings between GOPAs and PVA, and the thermal stability and mechanical properties of PVAGOPs film are improved effectively.

    更新日期:2018-01-03
  • 更新日期:2018-01-03
  • The cavitation erosion of ultrasonic sonotrode during large-scale metallic casting: Experiment and simulation
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-02
    Yang Tian, Zhilin Liu, Xiaoqian Li, Lihua Zhang, Ruiqing Li, Ripeng Jiang, Fang Dong

    Ultrasonic sonotrodes play an essential role in transmitting power ultrasound into the large-scale metallic casting. However, cavitation erosion considerably impairs the in-service performance of ultrasonic sonotrodes, leading to marginal microstructural refinement. In this work, the cavitation erosion behaviour of ultrasonic sonotrodes in large-scale castings was explored using the industry-level experiments of Al alloy cylindrical ingots (i.e. 630 mm in diameter and 6000 mm in length). When introducing power ultrasound, severe cavitation erosion was found to reproducibly occur at some specific positions on ultrasonic sonotrodes. However, there is no cavitation erosion present on the ultrasonic sonotrodes that were not driven by electric generator. Vibratory examination showed cavitation erosion depended on the vibration state of ultrasonic sonotrodes. Moreover, a finite element (FE) model was developed to simulate the evolution and distribution of acoustic pressure in 3-D solidification volume. FE simulation results confirmed that significant dynamic interaction between sonotrodes and melts only happened at some specific positions corresponding to severe cavitation erosion. This work will allow for developing more advanced ultrasonic sonotrodes with better cavitation erosion-resistance, in particular for large-scale castings, from the perspectives of ultrasonic physics and mechanical design.

    更新日期:2018-01-03
  • Ultrasound Assisted Dispersion of Bi2Sn2O7-C3N4 Nanophotocatalyst over Various Amount of Zeolite Y for Enhanced Solar-Light Photocatalytic Degradation of Tetracycline in Aqueous Solution
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2018-01-02
    Shirin Heidari, Mohammad Haghighi, Maryam Shabani

    Bi2Sn2O7-C3N4/Y nanophotocatalyst with various ratios of zeolite and high activity under simulated solar light irradiation were successfully synthesized using ultrasound-assisted dispersion method. The effect of different amounts of zeolite (10, 20 and 30 wt.%) on the photocatalytic degradation of antibiotic tetracycline was investigated. The as-prepared nanophotocatalysts were characterized by XRD, FESEM, EDX, BET, FTIR, DRS and pHpzc techniques. The degradation results demonstrated that, Bi2Sn2O7-C3N4/Y(10) nanophotocatalyst with a degradation efficiency of about 80.4% is an optimum sample. This result can be attributed to the zeolite as a support that prevented the accumulation of Bi2Sn2O7-C3N4 active phase and increased access to active sites. Furthermore, it enhanced the adsorption capacity of tetracycline on the photocatalyst surface; that it is beneficial for tetracycline photocatalytic oxidation. Also the results of the DRS analysis indicated that the sharp absorption edge for optimum sample Bi2Sn2O7-C3N4/Y at about 480 nm and was active in the visible light range. Eventually, different operational parameters such as photocatalyst loading, concentrations of pollutant and pH solution were investigated. In addition, the degradation mechanism was suggested for TC removal.

    更新日期:2018-01-03
  • 更新日期:2018-01-02
  • Measurement of distribution of broadband noise and sound pressures in sonochemical reactor
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-30
    Keiji Yasuda, Tam Thanh Nguyen, Yoshiyuki Asakura

    Cross-sectional area distribution of broadband noise in a sonochemical reactor was measured to estimate reaction fields. A needle-type hydrophone scanned the sonochemical reactor in horizontal and vertical directions at one-millimeter interval. To show an absolute value of broadband noise, average of broadband sound pressure was defined. The distribution of sound pressures at the fundamental and second harmonic frequencies were also measured. In the case of driving frequency at 130 kHz, sonochemical reaction fields were observed in several ellipse shapes. The reaction fields in upper part of the reactor was high because cavitation bubbles moved upper part due to radiation force. The sound pressure distribution at the fundamental frequency showed existence of standing wave and reaction fields were weak at pressure antinode because cavitation bubbles were repelled by primary Bjerknes force. The sound pressure distribution at the second harmonic frequency indicated that the pattern of bubbles distribution resembled to that of reaction fields closely. In the case at 43 kHz, distributions of reaction fields and sound pressures were complex due to coupled vibration. The reaction fields were relatively weak in areas which had very high sound pressures at the fundamental frequency.

    更新日期:2017-12-31
  • Ultrasonic vs hydrothermal method: different approaches to convert fly ash into zeolite. How they affect the stability of synthetic products over time?
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-30
    Claudia Belviso

    The action of direct sonication (US) versus conventional hydrothermal method (HY) was investigated to determine the differences in the crystallization mechanism of zeolite formed from fly ash. The results showed that ultrasonic energy is decisive in very fast faujasite and A-type zeolite transformation into more stable sodalite phase. The data display the main presence of sodalite together with a low amount of faujasite and zeolite A after the first 3 hours of sonication. The full transformation of the latter two phases into sodalite takes place after 1 hour more of treatment. The samples incubated by hydrothermal process for 3 hours, instead, are characterized by the main presence of faujasite and A- type zeolites. The progressive synthesis of sodalite at the expense of the other two phases begins only after 4 hours of treatment. The conclusion is that the crystallization of zeolites by ultrasonic and hydrothermal method proceeds via two different mechanisms. The data also show that the two approaches affect the stability of the synthetic products in a different way over the years.

    更新日期:2017-12-31
  • Simple and fast preparation of graphene oxide@ melamine terephthaldehyde and its PVC nanocomposite via ultrasonic irradiation: Chemical, mechanical and thermal resistance Study
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-29
    Mahroo Khaleghi, Khadijeh Didehban, Meisam Shabanian

    Melamine terephthaldehyde modified graphene oxide (MTR-GO) with optimum content was easily prepared via ultrasonication method and used as anti-corrosion additive for Poly (vinyl chloride) (PVC). The effects of ultrasonicated MTR-GO on the mechanical, chemical and thermal resistance of the PVC were thoroughly studied. Change percentage of tensile strength and weight change percentage of PVC (P) and PVC/MTR-GO nanocomposite (PN) in acetone and sodium hypochlorite (NaClO) media at two different exposure temperature (20°C and 50°C) were examined. The PN sample showed lower change loss percentage of tensile strength in acetone uptake as compared with P sample at 20°C. In higher temperature (50°C), P sample was decomposed while PN still showed tensile data. The change loss percentage in tensile strength of PN sample showed 13% change at 50°C in sodium hypochlorite while P sample showed 63% change for the parameter. Protective behavior of MTR-GO nanofiller on PVC matrix against thermal HCl releasing was investigated by Congo red tests. The results showed that the nanocomposite release less amount of HCl as compare to the neat PVC.

    更新日期:2017-12-31
  • Microstructural and techno-functional properties of cassava starch modified by ultrasound
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-27
    Yuliana Monroy, Sandra Rivero, María A. García
    更新日期:2017-12-27
  • Green in water sonochemical synthesis of tetrazolopyrimidine derivatives by a novel core-shell magnetic nanostructure catalyst
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-27
    Ali Maleki, Jamal Rahimi, Oleg M. Demchuk, Agnieszka Z. Wilczewska, Radomir Jasiński
    更新日期:2017-12-27
  • Research on removing reservoir core water sensitivity using the method of ultrasound-chemical agent for Enhanced Oil Recovery
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-26
    Zhenjun Wang, Jiehao Huang

    The phenomenon of water sensitivity often occurs in the oil reservoir core during the process of crude oil production, which seriously affects the efficiency of oil extraction. In recent years, near-well ultrasonic processing technology attaches more attention due to its safety and energy efficient. In this paper, the comparison of removing core water sensitivity by ultrasonic wave, chemical injection and ultrasound–chemical combination technique are investigated through experiments. Results show that: lower ultrasonic frequency and higher power can improve the efficiency of core water sensitivity removal; the effects of removing core water sensitivity under ultrasonic treatment get better with increase of core initial permeability; the effect of removing core water sensitivity using ultrasonic treatment won’t get better over time. Ultrasonic treatment time should be controlled in a reasonable range; the effect of removing core water sensitivity using chemical agent alone is slightly better than that using ultrasonic treatment, however, chemical injection could be replaced by ultrasonic treatment for removing core water sensitivity from the viewpoint of oil reservoir protection and the sustainable development of oil field; ultrasound-chemical combination technique has the best effect for water sensitivity removal than using ultrasonic treatment or chemical injection alone.

    更新日期:2017-12-27
  • Novel Synthesis of WSe2–Graphene–TiO2 Ternary Nanocomposite via Ultrasonic Technics for High Photocatalytic Reduction of CO2 into CH3OH
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-26
    Biswas Md Rokon Ud Dowla, Asghar Ali, Kwang Youn Cho, Won-Chun Oh

    In the present work, we report the development of a WSe2–Graphene–TiO2 ternary nanocomposite via ultrasonic techniques and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The band-gap of the WSe2–Graphene–TiO2 was estimated to be about 1.62 eV which is suitable for photodegradation process under under ultraviolet UV/ Visible light irradiation. The photocatalytic potential of nanocomposites is investigated for CO2 reduction to CH3OH. WSe2–G–TiO2 with an optimum loading of graphene of 8 wt% showed the high photoactivity, gaining a total CH3OH yield of 6.3262 µmol g-1h-1 after 48 h. This excellent photoreduction activity is owing to the progressive synergistic relation between WSe2/TiO2 and graphene components in our heterogeneous system.

    更新日期:2017-12-27
  • Electrochemical mechanism of tin membrane electrodeposition under ultrasonic waves
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-24
    Tianxiang Nan, Jianguang Yang, Bing Chen

    Tin was electrodeposited from chloride solutions using a membrane cell under ultrasonic waves. Cyclic voltammetry(CV), linear sweep voltammetry(LSV), chronoamperometry(CHR), and chronopotentiometry were applied to investigate the electrochemical mechanism of tin electrodeposition under ultrasonic field. Chronoamperometry curves showed that the initial process of tin electrodeposition followed the diffusion controlled three-dimensional nucleation and grain growth mechanism. The analysis of the cyclic voltammetry and linear sweep voltammetry diagrams showed that the application of ultrasound can change the tin membrane electro-deposition reaction from diffusion to electrochemical control, and the optimum parameters for tin electrodeposition were H+ concentration 3.5 mol·L-1, temperature 35°C and ultrasonic power 100 W. The coupling ultrasonic field played a role in refining the grain in this process. The growth of tin crystals showed no orientation preferential, and the tin deposition showed a tendency to form a regular network structure after ultrasonic coupling. While in the absence of ultrasonic coupling, the growth of tin crystals has a high preferential orientation, and the tin deposition showed a tendency to form tin whiskers. Ultrasonic coupling was more favorable for obtaining a more compact and smoother cathode tin layer.

    更新日期:2017-12-27
  • Iodine-Enhanced Ultrasound Degradation of Sulfamethazine in Water
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-24
    Xiao-yu Yang, Hong Wei, Ke-bin Li, Qiang He, Jian-cang Xie, Jia-tong Zhang

    This study investigated sulfamethazine (SMT) ultrasound degradation, enhanced by iodine radicals, generated by potassium iodide (KI) and hydrogen peroxide (H2O2) in situ. The results showed that the ultrasound/H2O2/KI (US/H2O2/KI) combination treatment achieved an 85.10±0.45% SMT removal (%) in 60 min under the following conditions: pH = 3.2, ultrasound power of 195 W, initial SMT concentration of 0.04 mmol·L-1, H2O2 concentration of 120 mmol·L-1, and KI concentration of 2.4 mmol·L-1. UV-Vis spectrophotometric monitoring of molecular iodine (I2) and triiodide (I3-) revealed a correlation between the SMT degradation and the iodine change in the solution. Quenching experiments using methanol, t-butanol and thiamazole as radical scavengers indicated that iodine radicals, such as I· and I2-·, were more important than hydroxyl radicals (HO·) for SMT degradation. SMT degradation under the US/H2O2/KI treatment followed pseudo-first order reaction kinetics. The activation energy (Ea) of SMT degradation was 7.75±0.61 kJ·mol-1, which suggested the reaction was controlled by the diffusion step. Moreover, TOC removal was monitored, and the obtained results revealed that it was not as effective as SMT degradation under the US/H2O2/KI system.

    更新日期:2017-12-27
  • Preparation and characterization of CNTs/UHMWPE nanocomposites via a novel mixer under synergy of ultrasonic wave and extensional deformation
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-23
    Xiaochun Yin, Sai Li, Guangjian He, Yanhong Feng, Wen Jingsong

    In this work, design and development of a new melt mixing method and corresponding mixer for polymer materials were reported. Effects of ultrasonic power and sonication time on the carbon nanotubes (CNTs) filled ultra high molecular weight polyethylene (UHMWPE) nanocomposites were experimentally studied. Transmission Electron Microscopy images showed that homogeneous dispersion of CNTs in intractable UHMWPE matrix is successfully realized due to the synergetic effect of ultrasonic wave and extensional deformation without any aid of other additives or solvents. Differential scanning calorimetry results revealed an increase in crystallinity and crystallization rate due to the finer dispersion of the CNTs in the matrix which act as nucleating point. Composites’ complex viscosity and storage modulus decreased sharply at first and then leveled off with the increase of sonication time or the ultrasonic power. The thermal stability and the tensile strength of the CNTs/UHMWPE nanocomposites improved by using this novel mixing method. This is the first method that combined the ultrasonic wave and the extensional deformation in which the elongation rate, sonication time and ultrasonic power can be adjusted simultaneously during mixing. The novel mixer offers several advantages such as environment-friendly, high mixing efficiency, self-cleaning and wide adaptability to materials.

    更新日期:2017-12-27
  • 更新日期:2017-12-27
  • Comparison of conventional and ultrasonic method for dyeing of spunbond polyester nonwoven fabric
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-23
    Pelin Altay, Gülay Ӧzcan, Meltem Tekçin, Gizem Şahin, Semiha Çelik

    Nonwoven spunbonded polyester has wide applications for both household goods and home furnishings and their usage has continually been growing. Nowadays, coloration of nonwoven fabrics is performed using conventional methods. Conventional polyester dyeing is an energy-intensive process as the dyeing is carried out above 120 oC to obtain efficient diffusion of dye. Furthermore, these high temperatures may cause some harmful effects on delicate nonwoven structures. Ultrasound assisted textile dyeing is an alternative method of conventional dyeing of textile materials, providing energy saving by reduced process temperature and time, lower consumptions of auxiliaries with increased dyeing efficiency. This paper focuses on comparing the conventional (high temperature (HT) and carrier dyeing) and ultrasonic dyeing of nonwoven spunbonded polyester fabrics to investigate the effect of ultrasound energy on dyeing performance. Experimental results indicated that highest or comparable dyeing performance can be achieved with ultrasound dyeing at lower temperature (85 0C, 60 min.) without carrier as compared to carrier dyeing (100 oC, 60 min.) and HT dyeing (130 0C, 60 min.), providing an increase of dye depth depending on the dye concentration and basis weight of the fabric. It was evidently seen that highest basis weight of fabric (107 g/m2) used in this study exhibited greater color yield for each dye concentrations (K/S value of 4.90 at 0.2% dye concentration) as compared to conventional ones. The effect of ultrasound energy on reductive washing and fastness properties were also evaluated.

    更新日期:2017-12-27
  • 更新日期:2017-12-22
  • Ultrasound-assisted synthesis and characterization of magnetite nanoparticles and poly(methyl methacrylate)/magnetite nanocomposites
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-21
    Maneesh Kumar Poddar, Mohammad Arjmand, Uttandaraman Sundararaj, Vijayanand S. Moholkar
    更新日期:2017-12-22
  • A Sonochemical Synthesis of Cyclodextrin Functionalized Au-FeNPs for Colorimetric Detection of Cr6+ in Different Industrial Waste Water
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-21
    Baishnisha Amanulla, Hema Kalyani Rama Subbu, Sayee Kannan Ramaraj
    更新日期:2017-12-22
  • Ultrasound-assisted crystallization of lactose in the presence of whey proteins and κ-carrageenan
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-20
    Yanira I. Sánchez-García, Karen S. García-Vega, Martha Y. Leal-Ramos, Ivan Salmeron, Néstor Gutiérrez-Méndez

    The conventional process of lactose crystallization is prolonged, hardly controllable and the crystals have low quality. In this work, the effect of ultrasound on the crystallization of lactose in an aqueous system was assessed. Additionally, it was studied how the presence of whey proteins (which are a common impurity) and κ-carrageenan (that possess high water-binding capacity) could modify the process of lactose crystallization. Lactose solutions at 25% were sonicated in a continuous flow chamber at two different energy densities (9 and 50 J mL-1) before the start of crystallization. Some of these lactose solutions were previously added with κ-carrageenan (0, 150 and 300 mg L-1), with whey proteins (0.64%) or with both at the same time. Ultrasound sped up the rate of crystallization, decreased the crystal’s size and narrowed the crystal size distribution (CSD). The presence of whey proteins accelerated the process of crystallization but induced the formation of amorphous lactose. Likewise, the rate of lactose crystallization was improved by the addition of 150 mg L-1 of carrageenan. Whereas, the combination of carrageenan and whey proteins generated the smallest crystals (6 μm), the narrowest CSD and minimized the formation of amorphous lactose.

    更新日期:2017-12-20
  • Effects of ultrasonic vibration on microstructure and mechanical properties of nano-sized SiC particles reinforced Al-5Cu composites
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-19
    Jianyu Li, Shulin Lü, Shusen Wu, Qi Gao

    Ultrasonic vibration(UV) treatment has been successfully applied to improve the particles distribution of nano-sized SiC particles(SiCp) reinforced Al-5Cu alloy matrix composites which were prepared by combined processes of dry high energy ball milling and squeeze casting. When UV treatment is applied, the distribution of nano-sized SiCp has been greatly improved. After UV for 1 min, large particles aggregates are broken up into small aggregates due to effects of cavitation and the acoustic streaming. After UV for 5 min, all the particles aggregates are dispersed and the particles are uniformly distributed in the composites. Compared with the Al-5Cu matrix alloy, the ultimate tensile strength, yield strength and elongation of the 1wt% nano-sized SiCp/Al-5Cu composites treated by UV for 5 min are 270 MPa, 173 MPa and 13.3%, which are increased by 7.6%, 6.8% and 29%, respectively. The improvements of mechanical properties after UV are attributed to the uniform distribution of nano particles, grain refinement of aluminum matrix alloy and reduction of porosity in the composites.

    更新日期:2017-12-19
  • Ultrasonic-microwave assisted synthesis of three-dimensional polyvinyl alcohol carbonate/graphene oxide sponge and studies of surface resistivity and thermal stability
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-19
    Yunna Song, Yuehai Li, Jihui Li, Yongshen Li, Shuai Niu, Ning Li

    In the article, graphene oxide (GO) was prepared by flake graphite, nitric acid and peroxyacetic acid via the sonochemical method and characterized, and polyvinyl alcohol carbonate/GO composite (PVAC/GO composite) was synthesized by polyvinyl alcohol (PVA), dimethyl carbonate (DMC) and GO via the approach of transesterification in the case of ultrasonic-microwave synergistic effects and characterized, and three-dimensional PVAC/GO sponge (3D PVAC/GO sponge) was manufactured by PVAC/GO composite via the foaming approach and characterized, and the thermal stability and surface resistivity of 3D PVAC/GO sponge were investigated. Based on those, it had been attested that PVAC polymer was structured by DMC and PVA and had the six-membered lactone rings and the ether bonds, and PVAC/GO composite was constituted by 2D GO lattice and PVAC polymer, and 3D PVAC/GO sponge was constructed by PVAC/GO composite, and the surface resistivity of 3D PVAC/GO sponge with 0.00, 0.60, 1.20, 1.80 and 2.40 g of GO were 9.07 × 107, 6.02 × 107, 4.65 × 107, 2.47 × 107 and 1.06 × 107 ohms/sq, and the thermal stability of 3D PVAC/GO sponge had improved.

    更新日期:2017-12-19
  • The effects of solvent and ultrasonic irradiation in synthesis of thallium(I) nano supramolecular polymers and use them as template for synthesis of thallium(III) oxide nanostructures with desirable morphology
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-18
    Kamran Akhbari, Sepideh Karami, Zahra Saedi

    In order to study the effects of solvent and ultrasonic irradiation on formation of [Tl(HTar)]n (1) and/or [Tl2(Tar)]n (2), [H2Tar = (+)-tartaric acid] supramolecular polymers, we designed some experiments and synthesized four samples of 1 under the reaction of H2Tar and TlNO3 by sonochemical process and as the bulk samples. Nanostructures of compounds 1 and 2 as the bulk samples could be synthesized without ultrasonic irradiation, too. In the presence of ultrasonic waves, with acetonitrile solvent, more discrete nanoparticles were obtained. These four samples have been used as new precursors for preparation of thallium(III) oxide nanostructures via solid-state thermal decomposition process. There is a direct relationship between the morphology of initial precursors and resulting thallium(III) oxide nanostructures. These nanostructures were characterized by IR spectroscopy, X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM).

    更新日期:2017-12-18
  • Synthesis and sonocatalytic performance of a ternary magnetic MIL-101(Cr)/RGO/ZnFe2O4 nanocomposite for degradation of dye pollutants
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-18
    Ladan Nirumand, Saeed Farhadi, Abedin Zabardasti, Alireza Khataee

    In this study, new ternary magnetic MIL-101(Cr)/RGO/ZnFe2O4 catalyst (with 30% wt of ZnFe2O4) was synthesized via a hydrothermal route for sonodegradation of organic dyes. The structural, optical and magnetic properties of the nanocomposite were detected by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV-visible), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, vibrating sample magnetometer (VSM), atomic force microscopy (AFM), Raman spectroscopy and BET surface area analysis. To evaluate the sonocatalytic activity of the as-prepared MIL-101(Cr)/RGO/ZnFe2O4 nanocomposite, the H2O2-assisted degradation of organic dyes such as congo red (CR), methylene blue (MB), Rhodamine B (RhB) and methyl orange (MO) in aqueous solution was studied under ultrasound irradiation. The obtained results indicated that the ternary MIL-101(Cr)/RGO/ZnFe2O4 nanocomposite had better performance for sonodegradation of these dyes than MIL-101(Cr)/RGO, pure MIL-101(Cr) or ZnFe2O4. The enhanced sonocatalytic performance of the as-prepared ternary nanocomposite could be attributed to the fast generation and separation of charge carriers (electrons and holes) in ZnFe2O4and MIL-101(Cr) and their transfer to the surface of graphene sheets. Moreover, the relatively high specific surface area of the MIL-101(Cr)/rGO and magnetic property of ZnFe2O4 improve the degradation efficiency of the dyes. The recovery of the ternary magnetic sonocatalyst from treated water could be easily achieved using an external magnetic field. The main influence factors on the sonocatalytic activity such as catalyst dosage and dye initial concentration were also investigated. The trapping experiments indicated that •OH radicals are the prominent active species in dye degradation. In addition, the reusability test, was also carried out to ensure the stability of the employed sonocatalyst.

    更新日期:2017-12-18
  • A comparison of nitrogen-doped sonoelectrochemical and chemical graphene nanosheets as hydrogen peroxide sensors
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-18
    Yi-Shan Wu, Zhe-Ting Liu, Tzu-Pei Wang, Su-Yang Hsu, Chien-Liang Lee

    Nitrogen-doped graphene nanosheet (N-SEGN) with pyrrolic nitrogen and 5-9 vacancy defects has been successfully prepared from a hydrothermal reaction of tetra-2-pyridinylpyrazine and sonoelectrochemistry-exfoliated graphene nanosheet, with point defects. Additionally, based on the same reaction using chemically reduced graphene oxide, nitrogen-doped chemically reduced graphene oxide (N-rGO) with graphitic nitrogen was prepared. The N-SEGN and N-rGO were used as a non-enzymatic H2O2 sensors. The sensitivity of the N-SEGN was 231.3 μA·mM-1·cm-2, much greater than 57.3 μA·mM-1·cm-2 of N-rGO. The N-SEGN showed their potential for being a H2O2 sensor.

    更新日期:2017-12-18
  • 更新日期:2017-12-18
  • Influence of sound directions on acoustic field characteristics within a rectangle-shaped sonoreactor: numerical simulation and experimental study
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-16
    Zongbo Zhang, Tiantian Gao, Xiaoyang Liu, Dawei Li, Jiawei Zhao, Yuqi Lei, Yankui Wang

    Acoustic field intensity and distribution are the most important factors for the efficiency of ultrasonic processing. Recent simulation studies suggested that sound direction could influence both acoustic field intensity and distribution, but this influence has scarcely been investigated experimentally so far. In this work, we systematically studied the influence of sound directions on the acoustic field with up to five directions via both simulation and experiment. Fluid-structure interaction (FSI) harmonic response simulation and aluminum foil erosion experiment were employed to study the acoustic field under different directional combinations of ultrasonic sources. Results of simulation coincided well with that of experiment, which indicated that acoustic intensity, uniformity and cavitation characteristics were significantly affected by sound directions. Based on the results, several influence rules of sound directions were proposed. Optimal acoustic field with sound intensity of 30 times higher than that of single-wall excitation and severe cavitation volume of 95% was obtained. This work provides useful guidelines for acoustic field design of high-intensity ultrasonic apparatus.

    更新日期:2017-12-18
  • Ultrafast monitoring and control of subharmonic emissions of an unseeded bubble cloud during pulsed sonication
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-16
    Corentin Cornu, Matthieu Guédra, Jean-Christophe Béra, Hao-Li Liu, Wen-Shiang Chen, Claude Inserra

    In the aim of limiting the destructive effects of collapsing bubbles, the regime of stable cavitation activity is currently targeted for sensitive therapeutic applications such as blood-brain barrier opening by ultrasound. This activity is quantified through the emergence of the subharmonic component of the fundamental frequency. Due to the intrinsically stochastic behavior of the cavitation phenomenon, a better control of the different (stable or inertial) cavitation regimes is a key requirement in the understanding of the mechanisms involving each bubble-induced mechanical effect. Current strategies applied to stable cavitation control rely on the use of either seeded microbubbles or a long-lasting pulse to reinitiate subharmonic emission. The present work aims at developing an ultrafast (inferior to 250μs 250 μ s ) monitoring and control of subharmonic emissions during long-pulsed (50 ms) sonication. The use of a FPGA-based feedback loop provides reproducibile level of subharmonic emissions combined with temporal stability during the sonication duration. In addition, stable cavitation events are differentiated from the broadband noise characterizing inertial cavitation activity, with perspectives in the discrimination of the involved mechanisms underlying bubble-mediated therapeutic applications.

    更新日期:2017-12-18
  • 更新日期:2017-12-18
  • 更新日期:2017-12-18
  • Synthesis of poly(acrylamide-co-itaconic acid)/MWCNTs superabsorbent hydrogel nanocomposite by ultrasound-assisted technique: Swelling behavior and Pb (II) adsorption capacity
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-16
    Alireza mohammadinezhad, Gholam Bagheri Marandi, Majid Farsadrooh, Hamedreza Javadian

    In this research, the poly (acrylamide-co-itaconic acid)/multi walled carbon nanotubes (P(AAm-co-IA)/MWCNTs) as a novel superabsorbent hydrogel nanocomposite was synthesized by graft copolymerization of acrylamide (AAm) and itaconic acid (IA) mixture in the presence of the MWCNTs using ammonium persulfate (APS) as a free radical initiator and methylenebisacrylamide (MBA) as a crosslinker under ultrasound-assisted condition. The blank P(AAm-co-IA) hydrogel and its composite with the MWCNTs were characterized by means of SEM, FTIR, XRD and TGA methods. The effects of different parameters such as pH, time, the MWCNTs content and salt solutions on swelling behavior were investigated. The stability of the hydrogel increased by any increase in the MWCNTs content, which might be attributed to the hydrophobic nature of the MWCNTs as well as the increase of the crosslinker density. The water retention capacity (WRC) of the P(AAm-co-IA) hydrogel increased in the presence of the MWCNT (10 wt%). The synthesized hydrogel nanocomposite was studied for Pb (II) adsorption from aqueous solution. The effects of different parameters such as contact time (5-90 min), Pb (II) initial concentration (25-175 mg/L) and initial pH (1.5-4.5) of solution on Pb (II) adsorption were investigated by batch method. In comparison to P(AAm-co-IA) hydrogel, the P(AAm-co-IA)/MWCNTs hydrogel nanocompoite showed better adsorption behavior toward Pb (II). One of the most important aspects of this research was to investigate the effects of ultrasonic waves on polymer matrix and its ability.

    更新日期:2017-12-18
  • Ultrasound Assisted Enzymatic Degumming of Crude Soybean Oil
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-16
    Nishant S. More, Parag R. Gogate

    The present work deals with ultrasound assisted enzymatic degumming (UAED) of crude soybean oil quantifying the extent of degumming (EOD), cavitational yield and synergistic index (f) for the combination approaches. The effect of different operating parameters such as enzyme loading, pH, presence of water, temperature and ultrasonic power on the EOD has been investigated. Ultrasound combined with enzyme at loading of 2.0 ml/L resulted in EOD as 92.2% under ambient conditions. Addition of water (5%) in combination with ultrasound and enzyme at 2.0 ml/L loading and pH of 5 resulted in enhanced EOD (98.4%) in 120 min of treatment. The extent of phospholipid separation was also dependent on the power dissipation and it was observed that maximum phospholipids separation was obtained at 100 W. Scale-up studies were performed at 500 ml and 1 L operating volume under optimized conditions of 2.0 ml/L as the enzyme loading, pH of 5, 5% water addition and ultrasonic power of 100 W where 93.63% and 91.15% phospholipid separation respectively was obtained. The effects of ultrasonic treatment were also quantified in terms of the acid value reduction (final value less than 1) and oxidative stability (TOTOX less than 4) for the processed oil. It was demonstrated that suitable reduction in acid value and oxidative stability is effectively obtained using UAED with much higher efficacy as compared to only ultrasound or only enzymatic treatment.

    更新日期:2017-12-18
  • Cavitation field analysis for an increased efficiency of ultrasonic sludge pre-treatment using a novel hydrophone system
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-16
    Jochen Bandelin, Thomas Lippert, Jörg E. Drewes, Konrad Koch

    The generation of cavitation fields for the pre-treatment of anaerobic sludge was studied by means of a novel acoustic measuring system. The influence of different reactor dimensions (i.e., choosing reaction chamber widths of 40, 60 and 80 mm) on the cavitation intensity was determined at various solid contents, flow rates and static pressures. Results suggest that the cavitation intensity is significantly reduced by the sonication of liquids with a high solid content. By increasing the pressure to 1 bar, the intensity of bubble implosions can be enhanced and the sound attenuation in the solid fraction is partly compensated compared to ambient pressure. However, a further increase in pressure to 2 bars has a detrimental effect due to the suppression of powerful bubbles. A reduction of the reactor gap permits an intensification of the treatment of waste activated sludge (WAS) by concentrating the ultrasound power from 6 to 18 dB. This effect is less relevant in digested sludge (DS) with its markedly lower total solids content (2.2% vs. 6.9 % of solids in WAS). Increasing the flow rate, resulting in a flow velocity of up to 7 m/min, has no influence on the cavitation intensity. By adapting the reactor design and the static pressure to the substrate characteristics, the intensity of the sonication can be notably improved. This allows the design of sonication devices that are suitable for the intensive treatment of wastewater sludge.

    更新日期:2017-12-18
  • 更新日期:2017-12-15
  • Numerical Simulation of Single Bubble Dynamics under Acoustic Travelling Waves
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-14
    Xiaojian Ma, Biao Huang, Yikai Li, Qing Chang, Sicong Qiu, Zheng Su, Xiaoying Fu, Guoyu Wang

    The objective of this paper is to apply CLSVOF method to investigate the single bubble dynamics in acoustic travelling waves. The Naiver-Stokes equation considering the acoustic radiation force is proposed and validated to capture the bubble behaviors. And the CLSVOF method, which can capture the continuous geometric properties and satisfies mass conservation, is applied in present work. Firstly, the regime map, depending on the dimensionless acoustic pressure amplitude and acoustic wave number, is constructed to present different bubble behaviors. Then, the time evolution of the bubble oscillation is investigated and analyzed. Finally, the effect of the direction and the damping coefficient of acoustic wave propagation on the bubble behavior are also considered. The numerical results show that the bubble presents distinct oscillation types in acoustic travelling waves, namely, volume oscillation, shape oscillation, and splitting oscillation. For the splitting oscillation, the formation of jet, splitting of bubble, and the rebound of sub-bubbles may lead to substantial increase in pressure fluctuations on the boundary. For the shape oscillation, the nodes and antinodes of the acoustic pressure wave contribute to the formation of the “cross shape” of the bubble. It should be noted that the direction of the bubble translation and bubble jet are always towards the direction of wave propagation. In addition, the damping coefficient causes bubble in shape oscillation to be of asymmetry in shape and inequality in size, and delays the splitting process.

    更新日期:2017-12-15
  • 更新日期:2017-12-15
  • Synthesis and multifunctionality of (CeO2-NiO) nanocomposites via sonochemical technique
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-12
    A.A. Farghali, M.H. Khedr, S.I. El-Dek, A.E. Megahed

    CeO2, NiO and their nanocomposite were synthesized using facile sonochemical technique. XRD assure single phase CeO2 and NiO while the nanocomposite consists of the two phases only. CeO2 nanoparticles possess cubic shape, NiO was formed in nanorods, and CeO2 decorated the NiO nanorods in the nanocomposite. The magnetic behavior of the nanocomposite lies between those of the two parents with a ferromagnetic tendency. Metal oxide nanoparticles acted as catalyst in the formation of carbon nanofibers (CNFs), while the nanocomposite leads to the production of carbon nanotubes. The photocatalyst (CeO2-NiO) achieved complete dye degradation (100%) in light for the tested dye at 50 min. The decay products were analyzed using GC mass confirming mineralization of Bb red dye.

    更新日期:2017-12-13
  • Combination of ultrasound-treated 2D g-C3N4 with Ag/black TiO2 nanostructure for improved photocatalysis
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-12
    Wan-Kuen Jo, Hee-Jin Yoo

    Herein, nanosheets of g-C3N4 (CN), prepared using a green ultrasonication process under various conditions, were combined with Ag/black TiO2 nanocomposites (AgBT) to create two-dimensional (2D) CN/Ag/black TiO2 tri-composites (CNAgBT). The thickness of the CN sheets varied with the ultrasonication conditions. The CNAgBT sample prepared using ultrasound-treated CN exhibited the highest average photocatalytic efficiencies for the degradation of two model pollutants, followed in decreasing order by AgBT, black TiO2 (BT), sheet CN, bulk CN, and TiO2. The order of pollutant degradation efficiencies by the photocatalysts was consistent with that of the charge carrier separation efficiencies. The degradation efficiency of the CNAgBT increased as the CN-to-AgBT ratio increased from 0.05 to 0.1, but decreased gradually for higher ratios between 0.15 and 0.20, indicating a lower optimal CN-to-AgBT ratio. A plausible photocatalytic degradation mechanism for the CNAgBT nanocomposites was proposed. Additionally, CNAgBT with a CN-to-AgBT ratio of 0.1 displayed a higher hydrogen generation rate with a maximum value of 21.5 mmol g-1 over 5 h than those of the AgBT and BT. Overall, the CNAgBT prepared using ultrasonication-treated CNs showed enhanced photocatalytic performance for both pollutant degradation and hydrogen generation.

    更新日期:2017-12-12
  • Ultra-Sonication Assisted Cross-linking of Cellulose Polymers
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-11
    Inimfon A. Udoetok, Lee D. Wilson, John V. Headley

    Cross-linked cellulose-epichlorohydrin polymers were synthesized by a conventional heating with stirring (C-EP heating) and a parallel process using ultra-sonication (C-EP sonication) in the presence of aqueous ammonia. Structural characterization of modified cellulose was carried out using FTIR/13C solid state NMR spectroscopy and thermal methods (DSC and TGA) to characterize the cross-linked products by conventional versus sonication assisted synthesis. Evidence of products with variable textural properties and morphology was supported by nitrogen gas adsorption, solvent swelling, and microscopy (SEM, TEM) results. C-EP sonication possess greater cross-linker content judging by the loss of the cellulose fibril structure which was facilitated by acoustic cavitation effects due to ultra-sonication. Equilibrium sorption studies in aqueous solution with 2-naphthoxy acetic acid (NAA) revealed that C-EP heating had slightly greater sorption capacity than C-EP sonication at alkaline pH. By contrast, C-EP sonication had greater uptake of NAA at acidic pH. Kinetic uptake studies at pH 3 is described by the pseudo-second order model, where the surface sites of C-EP heating became saturated within ca. 75 minutes; whereas, ca. 350 minutes occurred for C-EP sonication. This study demonstrates that the yield of sonication assisted cross-linking of cellulose is greater with improved adsorption properties. The study also reveals the utility of sonicated assisted synthesis for the valorization and utilization of cellulose modified materials.

    更新日期:2017-12-11
  • In-Situ Sonosynthesis of Hedgehog-like Nickel Nanoparticles on Polyester Fabric Producing Magnetic Properties
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-11
    Sepideh Afshari, Majid Montazer

    Recently, nano finishing of textiles is increasingly attracted many researchers to create new features on the products. Here a new fabric is introduced through simultaneous aminolysis and hydrolysis of polyester along with in-situ sonosynthesis of hedgehog shaped nickel nanoparticles on the fabric with magnetic properties. To do this, nickel sulfate, hydrazine hydrate, sodium hydroxide and polyvinylpyrrolidone (PVP) were used as a precursor, reducing agent, alkali and stabilizer respectively. Nickel sulfate was reduced to nickel nanoparticles with hydrazine hydrate at the adjusted pH with NaOH in the presence of PVP at 75 °C for 2 h. The polyester fabric was aminolyzed and hydrolyzed produced various functional groups on the fabric surface assisted nucleation and stabilization of nickel nanoparticles. The morphology, crystal phase, magnetic properties and chemical structure of the treated fabrics were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), and energy dispersive X-ray spectroscopy (EDX). The optimized sample treated with 3.19 (mL) hydrazine hydrate, 3.99 (mL) sodium hydroxide and 0.41 (g) nickel sulfate showed reasonable saturation magnetization value of 4.5 emu g-1. The treated fabrics showed no antibacterial and antifungal behavior indicating the safety of the products.

    更新日期:2017-12-11
  • Introducing ultrasonic falling film evaporator for moderate temperature evaporation enhancement
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-11
    Maryam Dehbani, Masoud Rahimi

    In the present study, Ultrasonic Falling Film (USFF), as a novel technique has been proposed to increase the evaporation rate of moderate temperature liquid film. It is a proper method for some applications which cannot be performed at high temperature, such as foodstuff industry, due to their sensitivity to high temperatures. Evaporation rate of sodium chloride solution from an USFF on an inclined flat plate compared to that for Falling Film without ultrasonic irradiation (FF) at various temperatures was investigated. The results revealed that produced cavitation bubbles have different effects on evaporation rate at different temperatures. At lower temperatures, size fluctuation and collapse of bubbles and in consequence induced physical effects of cavitation bubbles resulted in more turbulency and evaporation rate enhancement. At higher temperatures, the behavior was different. Numerous created bubbles joined together and cover the plate surface, so not only decreased the ultrasound vibrations but also reduced the evaporation rate in comparison with FF. The highest evaporation rate enhancement of 353% was obtained at 40 °C at the lowest Reynolds number of 250. In addition, the results reveal that at temperature of 40 °C, USFF has the highest efficiency compared to FF.

    更新日期:2017-12-11
  • Water-molecular emission from cavitation bubbles affected by electric fields
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-11
    Hyang-Bok Lee, Pak-Kon Choi

    Orange emission was observed during multibubble sonoluminescence at 1 MHz in water saturated with noble gas. The emission arose in the vicinity of the peeled ground electrode of a piezoceramic transducer exposed to water, suggesting that cavitation bubbles were affected by the electric fields that leaked from the transducer. The spectrum of the emission exhibited a broad component whose intensity increased towards the near-infrared region with peaks at 713 and 813 nm. The spectral shape was independent of the saturation gas of He, Ne, or Kr. The broad component was attributed to the superposition of lines due to vibration-rotation transitions of water molecules, each of which was broadened by the high pressure and electric fields at bubble collapse. An emission mechanism based on charge induction by electric fields and the charged droplet model is proposed.

    更新日期:2017-12-11
  • Synthesis of graphene/epoxy resin composite via 1,8- diaminooctane by ultrasonication approach for corrosion protection
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-09
    Yue Wu, Ningning Song, Wucong Wang, Yaping Zhao

    In this work, the preparation of the graphene/epoxy resin composite and its corrosion protection on the copper substrate were presented. The 1,8-diaminooctane-grafted-graphene (1,8-D-g-G) was synthesized using the carboxyl functional graphite and 1,8-diaminooctane by a one-pot process under ultrasonication in supercritical CO2. The structure and morphology of the as-prepared samples characterized by FTIR, XPS, TEM, AFM, and SEM confirmed that the graphite was exfoliated into the graphene and the latter reacted with the 1,8-diaminooctane via amidation to form the 1,8-D-g-G. The graphene/epoxy resin composite was readily achieved by the reaction of the epoxy resin with the 1,8-D-g-G. The electrochemical and salt spray tests were applied to assess the corrosion protection of the composite coating on the copper substrate. The results demonstrated that the composite exhibited excellent corrosion protection. Also, the mechanism of the co-occurred exfoliating process and the amidation reaction in one-pot under ultrasonication in supercritical CO2 was explored.

    更新日期:2017-12-10
  • Sonochemiluminescence in an aqueous solution of Ru(bpy)3Cl2
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-09
    G.L. Sharipov, A.M. Abdrakhmanov, B.M. Gareev, L.R. Yakshembetova

    The sonochemiluminescence spectra of electron-excited ions ∗[Ru(bpy)3]2+ was registered for the first time during sonolysis of argon saturated aqueous solutions of Ru(bpy)3Cl2 with low concentration. At single-bubble sonolysis, the luminescence band of ruthenium is recorded at a concentration of Ru(bpy)3Cl2 from 10–6 M, and at multibubble from 10–5 M. Possible mechanisms for the appearance of the band of a tris-bipyridyl ruthenium(II) complex on the background of an structureless continuum of water in the spectra of sonoluminescence are analyzed. Based on the results of the comparison of the sonoluminescence spectra of Ru(bpy)3Cl2 aqueous solutions with the sonoluminescence spectra of aqueous solutions of rhodamine B (which has a high quantum yield of photoluminescence) it was established that a possible mechanism of sonophotoluminescence does not play a decisive role in ruthenium sonoluminescence. The effect of radical acceptors (O2, C2H5OH, Cd2+, I–) on ruthenium sonoluminescence is analyzed. The most significant mechanism for the formation of electron-excited ions ∗[Ru(bpy)3]2+ during sonolysis is the sonochemiluminescence in oxidation-reduction reactions involving [Ru(bpy)3]2+ ions and radical products of sonolysis of water (OH, H, e–aq) in the solution volume.

    更新日期:2017-12-10
  • Swirling cavitation improves the emulsifying properties of commercial soy protein isolate
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-09
    Feng Yang, Xue Liu, Xian'e Ren, Yongchun Huang, Chengdu Huang, Kunming Zhang

    Since emulsifying properties are important functional properties of soy protein, many physical, chemical, and enzymatic methods have been applied to treat soy protein to improve emulsifying properties. In this study, we investigated the effects of swirling cavitation at different pressures and for different times on emulsifying and physicochemical properties of soy protein isolate (SPI). The SPI treated with swirling cavitation showed a significant decrease in particle size and increase in solubility. Emulsions formed from treated SPI had higher emulsifying activity and emulsifying stability indexes, smaller oil droplet sizes, lower flocculation indexes, higher adsorbed proteins, lower interfacial protein concentrations, and lower creaming indexes than those formed from untreated SPI, indicating that swirling cavitation improved the emulsifying properties of the SPI. Furthermore, swirling cavitation treatment significantly enhanced the surface hydrophobicity, altered the disulfide bond and exposed sulfhydryl group contents of the SPI. The secondary structure of the SPI was also influenced by swirling cavitation, with an increase in β-sheet content and a decrease in α-helix, β-turn, and random coil contents. In addition, several significant correlations between physicochemical and emulsifying properties were revealed by Pearson correlation analysis, suggesting that the physicochemical changes observed in treated SPI, including the decreased particle size, increased solubility and surface hydrophobicity, and enhanced β-sheet formation, may explain the improved emulsifying properties of the isolate. Thus, our findings implied that swirling cavitation treatment may be an effective technique to improve the emulsifying properties of SPI.

    更新日期:2017-12-10
  • Ultrasonic waveform upshot on mass variation within single cavitation bubble: investigation of physical and chemical transformations
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-09
    Kaouther Kerboua, Oualid Hamdaoui

    The mechanical disturbance created by an ultrasonic wave travelling through a liquid medium induces the formation of cavitation that oscillates due to rarefaction and compression of the wave. The duration and the magnitude of the pressure applied by the ultrasonic wave at each instant would generate a specific impact on the variation of the bubble radius, the temperature, the pressure and the mass inside it. In this paper, a numerical study is conducted to simulate four waveforms (sinusoidal, square, triangular and sawtooth) travelling an aqueous media saturated with oxygen with an amplitude of 1.5 and 2 atm and a frequency of 200, 300 and 500 kHz. The purpose is to highlight the mass evolution within acoustic cavitation bubble during one cycle due to physical transformations and sonochemical effect. The obtained results demonstrated that square signal enhances temperature and pressure growth inside the bubble, as well as mass transfer by evaporation and condensation. This leads to an improvement of produced quantities of free radicals but also to a selectivity of O as a major product in the detriment of HO2● and ●OH. These trends are less and less observed when passing to sinusoidal, triangular and square signal.

    更新日期:2017-12-10
  • Controllable Synthesis of (NH4)Fe2(PO4)2(OH)·2H2O Using Two-Step Route: Ultrasonic-intensified Impinging Stream Pre-treatment Followed by Hydrothermal Treatment
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-07
    Bin Dong, Guang Li, Xiaogang Yang, Luming Chen, George Z. Chen

    (NH4)Fe2(PO4)2(OH)·2H2O samples with different morphology are successfully synthesized via two-step synthesis route - ultrasonic-intensified impinging stream pre-treatment followed by hydrothermal treatment (UIHT) method. The effects of the adoption of ultrasonic-intensified impinging stream pre-treatment, reagent concentration (C), pH value of solution and hydrothermal reaction time (T) on the physical and chemical properties of the synthesised (NH4)Fe2(PO4)2(OH)·2H2O composites and FePO4 particles were systematically investigated. Nano- seeds were firstly synthesized using the ultrasonic-intensified T-mixer and these nano-seeds were then transferred into a hydrothermal reactor, heated at 170 °C for 4 hours. The obtained samples were characterized by utilising XRD, BET, TG-DTA, SEM, TEM, Mastersizer 3000 and FTIR, respectively. The experimental results have indicated that the particle size and morphology of the obtained samples are remarkably affected by the use of ultrasonic-intensified impinging stream pre-treatment, hydrothermal reaction time, reagent concentration, and pH value of solution. When such (NH4)Fe2(PO4)2(OH)·2H2O precursor samples were transformed to FePO4 products after sintering at 650°C for 10 hours, the SEM images have clearly shown that both the precursor and the final product still retain their monodispersed spherical microstructures with similar particle size of about 3 μm when the samples are synthesised at the optimised condition.

    更新日期:2017-12-07
  • Energy efficient room temperature synthesis of cardanol-based Novolac Resin using acoustic cavitation
    Ultrason. Sonochem. (IF 4.218) Pub Date : 2017-12-07
    Nilesh L. Jadhav, Sai Krishna C. Sastry, Dipak V. Pinjari

    The present study deals with synthesis of cardanol-cased novolac (CBN) resin by the condensation reaction between cardanol and formaldehyde using acoustic cavitation. It is a step-growth polymerization which occurs in the presence of an acid catalyst such as adipic acid, citric acid, oxalic acid, sulphuric acid and hydrochloric acid. CBN was also synthesised by a conventional method for the sake of comparison of techniques. The effect of molar ratio, effect of catalyst, effect of different catalyst and effect of power on the conversion to CBN has been studied. The synthesised CBN was characterized using the Fourier Transform Infra Red Spectroscopy (FTIR), Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance (NMR) Spectroscopy and Thermogravimetric Analysis (TGA). The reaction was monitored by the Acid value, free formaldehyde content and viscosity of the synthesised product. The reaction time required for the conventionally synthesised CBN was 5 hours (300 minutes) with 120°C as an operating temperature while sonochemically the time reduced to 30 minutes at room temperature. The amount of time and energy saved can be quantified. Ultrasound facilitated synthesis was found to be an energy efficient and time-saving method for the synthesis of novolac resin.

    更新日期:2017-12-07
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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