In the 1980's sonochemistry was considered to be a rather restricted branch of chemistry mainly involving the ways in which ultrasound could improve synthetic procedures, predominantly in ...heterogeneous systems and particularly for organometallic reactions. This volume traces the evolution of sonochemistry from a century ago when the effects of acoustic cavitation were first reported almost as a scientific curiosity, through the 1980's to the present. It describes the ways in which scientific interest grew rapidly during the 1990's with the formation of the European Society of Sonochemistry in 1990 and the launch of a new journal Ultrasonics Sonochemistry in 1994. It also includes two chapters relating to the evolution of the subject as seen through the particular experiences of the authors Tim Mason and Mircea Vinatoru, both pioneers of sonochemistry. One chapter is devoted to the ultrasonically assisted extraction (UAE) of chemicals from plant material. This also illustrates the different ways in which sonochemical technologies can be applied in both batch and flow systems leading to the development of large-scale processing. The other chapter relating to environmental protection shows the wide range of applications of sonochemistry in this important field for both biological and chemical decontamination.
•Review of the parameters that control ultrasonic cavitation and sonochemistry.•Primary and secondary parameters are defined and their influence determined.•Discussed are changes in chemical and gas ...environment.•Parameters are considered from the viewpoint of bubble structural instability.•Bubble instabilities induce fragmentation effecting sonochemical efficiency.
In this review the phenomenon of ultrasonic cavitation and associated sonochemistry is presented through system parameters. Primary parameters are defined and considered, namely; pressure amplitude, frequency and reactor design; including transducer type, signal type, vessel-transducer ratio, liquid flow, liquid height, liquid temperature and the presence of a reflective plate. Secondary parameters are similarly characterised and involve the use of gas and liquid additives to influence the chemical and physical environments. Each of the parameters are considered in terms of their effect on bubble characteristics and subsequent impact on sonochemical activity. Evidence suggests that via parametric variation, the reaction products and efficiency may be controlled. This is hypothesised to occur through manipulation of the structural stability of the bubble.
•The effect of the acoustic cavitation in the sonochemical process is reviewed.•The formation mechanism of the Au shell on Fe3O4 core NPs was proposed.•Sonochemical reduction produces unique ...conditions to reduce HAuCl4 to amorphous Au.•Versatile sonochemistry shows great promise for other types of core/shell growth.
Sonochemical synthesis (sonochemistry) is one of the most effective techniques of breaking down large clusters of nanoparticles (NPs) into smaller clusters or even individual NPs, which ensures their dispersibility (stability) in a solution over a long duration. This paper demonstrates the potential of sonochemistry becoming a valuable tool for the deposition of gold (Au) shell on iron oxide nanoparticles (Fe3O4 NPs) by explaining the underlying complex processes that control the deposition mechanism. This review summarizes the principles of the sonochemistry method and highlights the resulting phenomenon of acoustic cavitation and its associated physical, chemical and thermal effects. The effect of sonochemistry on the deposition of Au NPs on the Fe3O4 surface of various sizes is presented and discussed. A Vibra-Cell ultrasonic solid horn with tip size, frequency, power output of ½ inch, 20 kHz and 750 W respectively was used in core@shell synthesis. The sonochemical process was shown to affect the surface and structure of Fe3O4 NPs via acoustic cavitation, which prevents the agglomeration of clusters in a solution, resulting in a more stable dispersion. Deciphering the mechanism that governs the formation of Au shell on Fe3O4 core NPs has emphasized the potential of sonication in enhancing the chemical activity in solutions.
•Zn0.35Fe2.65O4 nanostructures were prepared by Sonochemical method for the first time.•Pure Zn0.35Fe2.65O4 nanostructure was prepared by adjusting synthesis parameters.•As prepared nanomaterials ...show highly photocatalytic activity under visible and UV light.
Zn0.35Fe2.65O4 nanostructure was prepared as a ferrite material by using a simple sonochemistry method. The effect of different parameters such as sonication time and power were studied. By increasing sonication power and time more Fe+3 ions reduced to Fe+2. This happens because H and OH radicals produced under sonication could act as a reduction agent. Therefore by increasing power and sonication time more Fe+3 ions reduced. Pure Zn0.35Fe2.65O4 nanostructure was formed when sonication time and power were 30 min and 40 W. Surface area for pure Zn0.35Fe2.65O4 nanostructure was 64 m2.g−1. Afterward, Zn0.35Fe2.65O4 nanostructures were applied to treat water containing different pollutants. As-prepared nanostructures degrade 60.8, 77.9, 55.2 and 44.0% of Acid Violet 7, Acid Blue 92, Acid Red 14, and Methyl Orange under visible light during 180 min irradiation. In addition, 94.5, 84.2, and 43.0% of AV7, PhR, and Ery were degraded under UV light during 120 min irradiation. The as-synthesized Zn0.35Fe2.65O4 nanostructure was characterized through the SEM, EDX, TEM, CV, DRS, BET, VSM, and XRD.
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•One-step sonochemical method for the synthesis of high flourescent C-dots (QY ∼16%).•The collapsing bubbles provide extreme, transient conditions for the formation of ...C-dots.•Parametrization has led enhancement of the amount of C-dots formations.•The synthesized C-dots have been deposited on a polyethylene film.
This work describes a one-step synthesis of carbon dots (C-dots), which is carried out by sonication of polyethylene glycol (PEG-400) for 0.5–3h. The effect of the various experimental parameters, such as sonication time, amplitude and temperature on the size and the fluorescence of the C-dots was studied. It was found that the average diameter of the C-dots is between 2 and 9nm, depending on the preparation conditions. The highest quantum yield of emission was ∼16%. These high fluorescence properties of the C-dots could be used for bioimaging and for solar cell applications.
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•Sonochemical treatment shows significant potential for PFAS removal.•Operational parameters influence sonochemical degradation of PFAS.•Chemical additives can enhance sonochemical ...degradation of PFAS.•Sonochemical degradation is affected by PFAS concentration and chemical structure.•Combination of sonochemistry and conventional techniques improves PFAS degradation.
Poly- and perfluoroalkyl substances (PFAS) have received considerable attention from environmental scientists and engineers because of their stability and widespread. Sonochemical process has been widely used in the environmental field to remove pollutants due to its advantages in terms of operational simplicity, no secondary pollutant formation and safety. Currently, many studies have reported sonochemical degradation of various PFAS in laboratory settings and showed excellent removal potential. This article reviewed the effects of different power densities, ultrasonic frequencies, temperatures, atmosphere conditions, additives, and initial concentration and chemical properties of PFAS on the sonochemical degradation of PFAS. Sonochemical methods combined with conventional techniques for PFAS removal were elaborated as well. Additionally, this article discussed the challenges and prospects of using sonochemical approaches for PFAS remediation.
•A new and facile sonochemical pathway to fabricate Nd2Zr2O7 nanostructures and nanocomposites was used.•Morus nigra extract was used for green synthesis of Nd2Zr2O7 nanostructures and ...nanocomposites.•The performance of Nd2Zr2O7 nanostructures and nanocomposites in NOx abatement was compared, for the first time.•Nd2Zr2O7-ZrO2 nanocomposite provide high surface for catalytic processes.•Nd2Zr2O7-ZrO2 nanocomposite exhibit superior performance for conversion of NOx to N2.
Here, we offer an easy and eco-friendly sonochemical pathway to fabricate Nd2Zr2O7 nanostructures and nanocomposites with the help of Morus nigra extract as a new kind of capping agent. For the first time, the performance of Nd2Zr2O7-based ceramic nanostructure materials has been compared upon NOx abatement. Diverse kinds of techniques have been employed to specify purity and check the attributes of the fabricated Nd2Zr2O7-based nanostructurs by Morus nigra extract. Outcomes revealed the successful fabrication of Nd2Zr2O7 nanostructures and nanocomposites applying Morus nigra extract through sonochemical pathway. All nanostructured samples have been fabricated through ultrasonic probe with power of 60 W (18 KHz). Further, the fabricated Nd2Zr2O7-based ceramic nanostructure materials can be applied as potential nanocatalysts with appropriate performance for propane-SCR-NOx, since the conversion of NOx to N2 for the best sample (Nd2Zr2O7-ZrO2 nanocomposite) was 70%. In addition, in case of Nd2Zr2O7-ZrO2 nanocomposite, the outlet quantity of CO as an unfavorable and unavoidable product was lower than the rest.
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Herein, we have developed Ln2Ce2O7 (Ln = Er, Ho) ceramic nanostructures through a rapid and green sonochemical approach and scrutinized their photocatalytic efficiency toward ...degradation of toxic pollutants under sunlight. Salvia rosmarinus extract is utilized as a morphology-directing agent in the sono-synthesis of the nanostructured Ln2Ce2O7 (Ln = Er, Ho), for the first time. Comprehensive characterization utilizing different techniques demonstrated that introducing of rare-earth metals, erbium and holmium, affected the textural, morphological, and optical features of the nanostructured ceria. The energy gap for pure cerium dioxide nanostructure was estimated to be 3.09 eV, while the energy gap for Ho2Ce2O7 and Er2Ce2O7 nanostructure was estimated at 2.9 and 2.66 eV, respectively. The narrowing of the energy gap was observed as a result of the introduction of rare-earth metals, erbium and holmium, especially erbium, into the nanostructured ceria. Investigation of the photocatalytic decomposition of various contaminants revealed that the introduction of erbium has remarkably enhanced the photocatalytic activity of nanostructured ceria. High photocatalytic performance (98.9%) and rate constant (0.0727 min−1) was observed for the Er2Ce2O7 nanostructure in the removal of eriochrome Black T. Improving the optical features of ceria nanostructure as well as enhancing its specific area were reasons that could increase the photocatalytic efficiency. The photocatalytic decomposition reactions in the removal of toxic contaminants were well accorded with the Pseudo-first order reaction kinetics. Besides, the nanostructured Er2Ce2O7 maintained its efficiency after ten reaction cycles and did not denote any notable decline in efficiency. The use of this novel porous nanostructure can be a potentially efficient solution for water treatment.
A novel photocatalyst CaSn(OH)
6 with middle-sagged micro-cube morphology was successfully synthesized via a facile sonochemical method. The as-synthesized sample was characterized by X-ray ...diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy and N
2 absorption–desorption. The photoactivity of the sample was evaluated by the degradation of benzene under UV irradiation. The results indicated that CaSn(OH)
6 showed much better photocatalytic activity and stability than that of TiO
2 (P25, Degussa Co.) under the same conditions. CaSn(OH)
6 also exhibited high activity for methyl orange photodegradation. Additionally, a possible mechanism of the photocatalysis over CaSn(OH)
6 was proposed.
Photocatalytic property of a novel cube-shaped CaSn(OH)
6.
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► A novel CaSn(OH)
6 with a middle sag on each face of micro-cube was synthesized. ► The sonochemical method was simple and economical. ► CaSn(OH)
6 showed higher activity and stability toward mineralizing benzene than P25. ► CaSn(OH)
6 exhibited good performance for photodegradation of MO. ► O
2·
−, H
2O
2 or ·OH played an important role in the photocatalytic process.
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