Syntheses and characterization of Sr(OH)2 and SrCO3 nanostructures by ultrasonic method

The Sr(OH)₂ and SrCO₃ nanostructures were synthesized by reaction of strontium(II) acetate and sodium hydroxide or tetramethylammonium hydroxide (TMAH) via ultrasonic method. Reaction conditions, such as the concentration of the Sr²⁺ ion, aging time, power of the ultrasonic device and alkali salts show important roles in the size, morphology and growth process of the final products. The pure crystalline SrCO₃ were obtained by heating of product at 400 °C. The Sr(OH)₂ and SrCO₃ nanostructures were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermal gravimetric (TG), differential thermal analyses (DTA) and the infrared spectroscopy (IR).     

Effective removal of organic pollution by using sonochemical prepared LaFeO3 perovskite under visible light

In the present work, LaFeO₃ perovskite was prepared via ultrasonic probe with power of 60 W and frequency of 18 KHz. LaFeO₃ nanorods were formed when sonication time was 20 min. In this research, green materials including corn, starch, and rice were used to control the size, morphology, and purity of final products. As-prepared LaFeO₃ nanostructures were used to purify water containing organic contaminants. LaFeO₃ nanostructures prepared by using corn, starch, and rice showed higher photocatalytic activity compare to LaFeO₃ nanostructures without natural capping agents. Using corn increased degradation efficiency by 65% under visible light. XRD results show that Fe₂O₃ appeared as an impurity when starch was used to prepare LaFeO₃ nanostructures. This impurity significantly boosts the degradation efficiency under UV light. Fe₂O₃ under UV light act as co-absorbent and boost efficiency by 43%. LaFeO₃ nanostructures were characterized by XRD, EDX, SEM, CV, BET, TEM, DRS and FT-IR.     

Self-assembled 3D La(OH)3 and La2O3 nanostructures: Fast microwave synthesis and characterization

Self-assembled three-dimensional (3D) urchin-like and flower-like La(OH)₃ nanostructures were successfully prepared for the first time via a facile and fast microwave-assisted solution-phase chemical method in 15 min. The obtained products were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The SEM results reveal that the urchin-like and flower-like La(OH)₃ nanostructures are ca. 3 μm and 6 μm in diameter, respectively. The urchin-like La(OH)₃ nanostructures are constructed by nanorods with diameters of about 300 nm and lengths of about 500 nm. The flower-like La(OH)₃ nanostructures are built from nanopetals about 100 nm thick. The effects of reaction time, microwave power, amount of tetraethyl ammonium bromide (TEAB), and surfactants on the preparation were systematically investigated. The possible formation mechanism of the 3D La(OH)₃ nanostructures was preliminarily discussed. Urchin-like and flower-like La₂O₃ nanostructures were obtained after calcining the La(OH)₃ nanostructures at 800 °C for 4 h. Urchin-like and flower-like La₂O₃:Eu³⁺ nanostructures were also prepared and their photoluminescence (PL) properties were investigated.     

Ultrasonic assisted synthesis,characterization and influence factors of monodispersed dumbbell-like YF3 nanostructures

In the present paper, we reported the successful synthesis of dumbbell-like YF₃ nanostructures with a high yield in a mixed system of water/N,N-dimethylformamide (DMF) under the assistance of ultrasound waves of 40 kHz with the ultrasonic power of 100% (200 W) at 65 °C for 2 h, employing Y₂O₃ (99.99%) and NH₄F as the starting reactants. The product was characterized by means of powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), selected area electron diffraction (SAED) pattern and field-emission scanning electron microscopy (SEM). Some factors influencing the morphology of YF₃ nanostructures, including the ultrasonic time and power, the amount of NH₄F, and the ratio of water/DMF, were systematically investigated. Research showed that the morphology of YF₃ could be tuned by the volume ratio of water/DMF. The roles of DMF and the ultrasonic wave in the formation of YF₃ nanostructures were discussed.     

Fabrication and characterization of ZnO micro and nanostructures prepared by thermal evaporation

A simple method of thermal evaporation to fabricate micro and nanostructures of zinc oxide was presented. ZnO micro and nanostructures, prepared under different quantity of O₂, were characterized by techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and analytical transmission electron Microscope. The SEM images indicated that the products prepared under the condition of sufficient O₂ were needle-like microrods and the samples synthesized under the condition of deficient O₂ were nanorods and nanowires with very high aspect ratio. The results of XRD and Raman shifts revealed that the ZnO micro and nanostructures synthesized under different quantity of O₂ were both single crystalline with the hexagonal wurtzite structure. The HRTEM images indicated that the ZnO nanowire prepared under the condition of deficient O₂ was single crystalline and grown along the direction of [0 0 1]. Photoluminescence measurement was carried out and it showed that the spectra of ZnO micro and nanostructures prepared under different quantity of O₂ exhibited similar emission features. In addition, the growth mechanism of ZnO micro and nanostructures was preliminarily discussed.     

Ultrasonically-enhanced mechanochemical synthesis of CaAl-layered double hydroxides intercalated by a variety of inorganic anions

CaAl-layered double hydroxides (CaAl-LDHs) were synthesised with various interlayer anions (CO₃²⁻, F⁻, Cl⁻, Br⁻ and I⁻) by mechanochemical pre-treatment followed by ultrasonic irradiation in aqueous media. The parameters of the syntheses (duration of pre-milling and sonication, quality of the aqueous media, temperature) were altered in order to optimise the procedure and to understand the formation of LDH and other secondary products. The products were characterised by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The optimisation resulted in close-to-phase-pure CaAl-LDHs, not only with carbonate and chloride interlayer anions, but the hard-to-intercalate bromide and iodide as well.     

Sono-assisted adsorption of organic compounds contained in industrial solution on iron nanoparticles supported on clay: Optimization using central composite design

Organic substance (O.S) in industrial phosphoric acid (IPA) solution is often tacked placed creates a major problem for IPA quality. This study was performed to assess the efficiency of Iron Intercalated Bentonite Nanoparticles (IIBN) coupled with the ultrasonic irradiation named sono-adsorption process for treating IPA 54% P₂O₅ contained O.S. XRD, SEM and BET were performed for the characterization of as-prepared adsorbent. Several conditions such as adsorbent dosage, molar ratio (OH/Fe) and time were investigated in retention experiments at acidic pH and T° of 40 ± 1 °C. The sono-assisted retention parameters were optimized by using NEMROOD software. The interaction impact of study condition on the final retention capability of the organism has been revealed by ANOVA software. Accordingly, the organic substance removal can be retained more than 83% by a sonication time of 0.5 h, absorbent dosage of 1.2 g/L and a molar ratio (OH/Fe) of 1.37. The absorbability of O.S was also evaluated by using the three parameters retention isotherms and kinetic analysis.     

Synthesis and characterization of CdS nanoparticle based multiwall carbon nanotube–maleic anhydride–1-octene nanocomposites

CdS nanoparticles were synthesized by sonication from cadmium chloride and thiourea using a multiwall carbon nanotube (MWCNT)–maleic anhydride (MA)–1-octene system as the matrix. The matrix was obtained by the “grafting from” approach from oxidized carbon nanotubes and maleic anhydride–1-octene. Multiwall carbon nanotubes used for reinforcing the matrix were synthesized by Catalytic Chemical Vapor Deposition using Fe–Co/Al₂O₃ as the catalyst. The obtained nanostructures were characterized by FTIR, XRD, Raman spectroscopy, TEM, SEM and UV–vis spectroscopy. The average CdS particle diameter was 7.9 nm as confirmed independently by TEM and XRD. UV–vis spectroscopy revealed that the obtained nanostructure is an appropriate base material for making optical devices. The novelty of this work is the use of the MWCNT–MA–1-octene matrix obtained via the “grafting from” approach for the synthesis of uniformly dispersed CdS nanocrystals by ultrasonic cavitation to obtain a polymer nanocomposite.     

Syntheses and characterization of Mg(OH)2 and MgO nanostructures by ultrasonic method

Magnesium hydroxide nanostructures have been synthesized by the reaction of magnesium acetate with sodium hydroxide via sonochemical method. Reaction conditions such as the Mg²⁺ concentration, aging time and the ultrasonic device power show important roles in the size, morphology and growth process of the final products. The magnesium oxide nanoparticles have been prepared by calcination of magnesium hydroxide nanostructures at 400 °C. The magnesium hydroxide and magnesium oxide nanostructures were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermal gravimetric (TG) and differential thermal analyses (DTA).     

Fabrication and sonocatalytic property of AgPO3 microsphere

AgPO₃ microspheres were prepared by a simple hydrothermal method. The AgPO₃ microspheres were characterized by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), Brunauer–Emmett–Teller (BET), UV–vis absorption spectroscopy (UV–vis), and photoluminescence (PL) measurement. SEM reveals that the AgPO₃ microspheres were constructed by the accumulation of small particles. The as-prepared AgPO₃ microspheres sonocatalytically degraded Rhodamine B (RhB) excellently under ultrasonic irradiation. The sonocatalytic ability results from the OH radicals induced by AgPO₃ microspheres under ultrasonic irradiation. The effects of other conditions on ultrasonic activity were also investigated. The content of OH radicals in the reaction system was determined to further verify the above conclusions.     

A general sonochemical approach to rapid synthesis of 1D single-crystalline MSn(OH)6 (M = Ba, Ca, Sr) nanostructures

A general sonochemical approach that allows for a facile, rapid synthesis of MSn(OH)₆ (M = Ba, Ca, Sr) one-dimension (1D) nanostructures has been developed. The resulting CaSn(OH)₆ products possessed a nanotubular structure while SrSn(OH)₆ and BaSn(OH)₆ showed nanowire-like structures. The as-synthesized MSn(OH)₆ products were characterized by XRD, SEM and TEM techniques. Owing that BaSn(OH)₆ nanowires, CaSn(OH)₆ nanotubes, and SrSn(OH)₆ nanowires takes different crystal structures respectively, they share different growth mechanisms. However, we found that in all three growing processes, both ultrasound irradiation and the presence of Na₂CO₃ in the synthetic procedure had an significant impact on the homogeneous nucleation and fast growth of 1D MSn(OH)₆ nanostructures. This approach represents a successful example for the fast construction of innovative inorganic nanostructures in the absence of any surfactants.     

Facile sonochemical synthesis of tellurium and tellurium dioxide nanoparticles: Reducing Te(IV) to Te via ultrasonic irradiation in methanol

In this study, tellurium (Te) nanostructures were synthesized via a facile sonochemical method by reducing TeCl₄ to Te under ultrasonic irradiation in methanol. Moreover, by carrying out the reaction in an alkaline environment TeO₂ nanoparticles were produced. According to our knowledge, it is the first time that without secondary reducing agent Te⁴⁺ are reduced to Te. Also, the effects of ultrasonic power, irradiation time, solvent, and surfactant on the morphology and particle size of Te nanostructures were investigated. The obtained products were characterized by XRD, SEM, EDS, FT-IR and DRS.     

Mixed-solvothermal synthesis of CdS micro/nanostructures and their optical properties

Several novel cadmium sulfide (CdS) micro/nanostructures, including cauliflower-like microspheres, football-like microspheres, tower-like microrods, and dendrites were controllably prepared via an oxalic acid-assisted solvothermal route using ethylene glycol (EG) and H₂O as pure and mixed solvents with different S sources. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electronic microscope (SEM) and UV-vis spectrophotometer (UV). It was found that CdS micro/nanostructures can be selectively obtained by varying the composition of solvent, concentration of oxalic acid, and sulfur sources. UV-vis absorption spectra reveal that their absorption properties are shape-dependent. The possible formation process of the CdS micro/nanostructures was briefly discussed. This route provides a facile way to tune the morphologies of CdS over a wide range.     

Ultrasound assisted synthesis of {[Cu2(BDC)2(dabco)].2DMF.2H2O} nanostructures in the presence of modulator; new precursor to prepare nano copper oxides

As a new precursor to prepare nano copper oxide, nanostructures of porous metal organic framework (MOF) {[Cu₂(BDC)₂(dabco)].2DMF.2H₂O} (1) have been synthesized in the presence of acetic acid as a modulator via sonochemical method. Different concentrations of metal ion, organic linkers, modulator reagent and also different sonication times were held to improve the quality of nanostructures. Ultrasound irradiation helps nucleation step of the oriented attachment of modulation method and nanoparticles with a few nanorods has been prepared. As prepared MOF was calcinated at 500 °C to prepare nano CuO and Cu₂O. Compound 1, CuO and Cu₂O nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD).     

Ultrasonication assisted and surfactant mediated synergistic approach for synthesis of calcium sulfate nano-dendrites

Calcium sulfate (CaSO₄) nano-dendrimers were fabricated successfully via ultrasonic irradiation method using calcium chloride [CaCl₂] and ammonium per sulfate [(NH₄)₂SO₄] as precursors in aqueous solution by using cetyl trimethyl ammonium bromide (CTAB) as chemical surfactants. Diffusion-induced branching growth mechanism (DIBGM), influenced with the action of head-group and hydrocarbon chain effect of cationic surfactants, was the backbone in the formation of CaSO₄ nano-dendrites. Fourier Transform Infra-red Spectroscopy (FTIR), X-Ray powder Diffraction (XRD), Atomic Emission Spectroscopy (AES), Selected Area Electron Diffraction (SAED), Field-Emission Scanning Electron Microscopy (FE-SEM), Energy-Dispersive Spectroscopy (EDS), Dynamic Light Spectroscopy (DLS) and BET surface area analyzer were used to characterize the products. Results obtained were compared with conventional stirring method that proved the superiority of sonication method to obtain well-crystalline nanostructures. Also, surfactant concentration, sonication frequency and time were noticed as the critical factors to generate such absolute morphologies at nano-crystalline size.     

Ultrasound-promoted coating of silk yarn with different morphology of magnesium hydroxide nanostructures

The growth of magnesium hydroxide nanostructures on silk yarn was achieved by sequential dipping steps in alternating bath of magnesium nitrate and potassium hydroxide under ultrasound irradiation. The effects of ultrasound irradiation, concentration, pH and sequential dipping steps on growth of the Mg(OH)₂ nanostructures have been studied. Morphology of the nanostructures, depending on pH and with decreasing pH from 13 to 8, changed from nanoparticle to nanoneedle. Results show a decrease in the particles size as the concentration and sequential dipping steps increased. The physicochemical properties of the nanostructures were determined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray (WDX).     

Ultrasound assisted chitosan coated iron oxide nanoparticles: Influence of ultrasonic irradiation on the crystallinity,stability, toxicity and magnetization of the functionalized nanoparticles

Due to unique reaction conditions of the acoustic cavitation process, ultrasound-assisted synthesis of nanoparticles has attracted increased research attention. In this study, we demonstrate the effect of ultrasonic irradiation on the crystallinity, stability, biocompatibility, and magnetic properties of chitosan-coated superparamagnetic iron oxide nanoparticles (CS-SPIONs). CS solution and colloidal suspension of SPIONs were mixed and sonicated using an ultrasonic probe of 1.3 cm tip size horn, frequency (20 kHz), and power (750 W). Different samples were sonicated for 1.5, 5, and 10 min with corresponding acoustic powers of 67, 40 and 36 W, and the samples were denoted S_1.5, S_5, and S₁₀, respectively. The samples were characterized using X-ray diffractometer (XRD), Energy dispersive X-ray (EDX), Transmission electronic microscope (TEM), Fourier transform infrared spectroscopy (FTIR), Zeta sizer, and vibrating sample magnetometer (VSM). Cell cytotoxicity and cell uptake were investigated with human embryonic kidney 293 (HEK-293) cells through MTT assay and Prussian blue staining, respectively. The sharp peaks of the XRD pattern were disappearing with an increase in the sonication period but a decrease in acoustic power. EDX analysis also demonstrates that atomic and weight percentages of the various elements in the samples were decreasing with an increase in the sonication period. However, the Zeta potential (ζ) values increase with an increase in the sonication period.The saturation magnetization (M_s) of the S_1.5 before and after the coating is 62.95 and 86.93 emu/g, respectively. Cell cytotoxicity and uptake of the S_1.5 show that above 70% of cells were viable at the highest concentration and the longest incubation duration. Importantly, the CS-SPIONs synthesized by the sonochemical method are non-toxic and biocompatible.     

BaMnO3 nanostructures: Simple ultrasonic fabrication and novel catalytic agent toward oxygen evolution of water splitting reaction

In the current paper, the main aim is to fabricate the BaMnO₃ nanostructures via the sonochemical route. The various factor, including precursors, reaction time and power of sonication can affect the shape, size, and purity of the samples. We utilized X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray energy dispersive spectroscopy (EDS) to characterize the BaMnO₃ nanostructures. The optical property of BaMnO₃ nanostructures was explored by Ultraviolet–visible spectroscopy (UV–vis) and the energy gap was suitable for catalytic activity (about 2.75 eV). Changing the precursor can affect the size, nanoparticle shape, architectures, and uniformity of the samples. We employed the BaMnO₃ nanostructures for O₂ evolution reaction as catalysts. It can observe that increasing the homogeneity of the catalysts can increase the efficiency of the Oxygen evolution reaction. The maximum amount of the O₂ evolution and the highest TOF and TON are related to nanoplate disc using barium salicylate as a precursor of barium. As a result, we can nominate the BaMnO₃ nanostructures as an effective and novel catalyst for water-splitting reaction.     

Dense coating of surface mounted CuBTC Metal-Organic Framework nanostructures on silk fibers, prepared by layer-by-layer method under ultrasound irradiation with antibacterial activity

The growth of Cu₃(BTC)₂ (BTC = 1,3,5-benzenetricarboxylate), also known as CuBTC and HKUST-1, Metal-Organic Framework (MOF) nanostructures on silk fibers were achieved by layer-by-layer technique in alternating bath of Cu(OAc)₂·2H₂O and H₃BTC solutions under ultrasound irradiation. The effect of pH, reaction time, ultrasound irradiation and sequential dipping steps in growth of the CuBTC Metal-Organic Framework nanostructures has been studied. These systems depicted a decrease in the size accompanying a decrease in the sequential dipping steps. In addition, dense coating of silk fibers with CuBTC MOF results in decrease the emission intensity of silk fibers. The silk fibers containing CuBTC Metal-Organic Framework exhibited high antibacterial activity against Escherichia coli and Staphylococcus aureus. The samples were characterized with powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) spectra and scanning electron microscopy (SEM). XRD analyses indicated that the prepared CuBTC MOF nanostructures on silk fibers were crystalline.     

Degradation of Acid Blue 25 in aqueous media using 1700 kHz ultrasonic irradiation: ultrasound/Fe(II) and ultrasound/H2O2 combinations

In this work, the sonolytic degradation of an anthraquinonic dye, C.I. Acid Blue 25 (AB25), in aqueous phase using high frequency ultrasound waves (1700 kHz) for an acoustic power of 14 W was investigated. The sonochemical efficiency of the reactor was evaluated by potassium iodide dosimeter, Fricke reaction and hydrogen peroxide production yield. The three investigated methods clearly show the production of oxidizing species during sonication and well reflect the sonochemical effects of high frequency ultrasonic irradiation. The effect of operational conditions such as the initial AB25 concentration, solution temperature and pH on the degradation of AB25 was studied. Additionally, the influence of addition of salts on the degradation of dye was examined. The rate of AB25 degradation was dependent on initial dye concentration, pH and temperature. Addition of salts increased the degradation of dye. Experiments conducted using distilled and natural waters demonstrated that the degradation was more efficient in the natural water compared to distilled water. To increase the efficiency of AB25 degradation, experiments combining ultrasound with Fe(II) or H₂O₂ were conducted. Fe(II) induced the dissociation of ultrasonically produced hydrogen peroxide, leading to additional OH radicals which enhance the degradation of dye. The combination of ultrasound with hydrogen peroxide looks to be a promising option to increase the generation of free radicals. The concentration of hydrogen peroxide plays a crucial role in deciding the extent of enhancement obtained for the combined process. The results of the present work indicate that ultrasound/H₂O₂ and ultrasound/Fe(II) processes are efficient for the degradation of AB25 in aqueous solutions by high frequency ultrasonic irradiation.