Sonochemical Time Research Articles

Synthesis of TiO<sub>2</sub> from TiOSO<sub>4</sub> Solution with Sonochemical Method

TiO2 is a semiconductor that possesses superior chemical and physical properties, widely used in various fields. In this research, the synthesis of TiO2 particles was carried out by the sonochemical method. Synthesis begins by mixing the precursor TiOSO4 in H2O with a ratio of the solvent volume (v/v) H2O/TiOSO4 20-80. TiO2 particles through sonochemically reduced for 15-75 minutes. Changes in particle diameter during the synthesis process are calculated by particle size analyzer. The results of the particle size analyzer showed that the increase in the solvent volume ratio causes the average diameter of TiO2 particles to increase with a heterogeneous size distribution. Conversely, the increasing time on sonochemical processing causes a very significant decrease in the average particle diameter. The best parameter in the sonochemical method was the lowest solvent volume ratio, 20, and the sonochemical time process of 75 minutes generated a single anatase phase 338 nm with a spherical shape.

Sonochemical degradation of ciprofloxacin by hydrogen peroxide and persulfate activated by ultrasound and ferrous ions

This paper evaluates the use of various oxidation methods such as ultrasonic/persulfate (US/PS), ultrasonic/hydrogen peroxide (US/H2O2), US/H2O2/Fe2+, US/PS/Fe2+, and the US/PS/H2O2/Fe2+ process and compares their potential in removal of ciprofloxacin (CIP). The results showed that US/PS/H2O2/Fe2+, was the most efficient among the studied processes. In US/PS/H2O2/Fe2+, 100% removal of CIP was achieved at pH 3 and 50 min of treatment when the initial concentration of CIP, H2O2, PS and Fe2+ were 25 mg/L, 4 mM, 6 mM and 1 mM, respectively. The results showed that with increasing ultrasonic power and increasing concentrations of H2O2, PS, and Fe2+, the removal percentage increases. Toxicity of CIP solution was scrutinized by Daphnia magna, and the US/PS/H2O2/Fe2+ process was able to provide toxicity elimination of 100% for the solution. Also, the equilibrium data for all processes followed first-order kinetics with a regression coefficient above 0.9, and the reaction rate constant for the US/PS/H2O2/Fe2+ process was higher than other systems. At 60 min of sonochemical time, the energy consumptions by US/PS, US/H2O2, US/H2O2/Fe2+, US/PS/Fe2+, and US/PS/H2O2/Fe2+ were 105.5, 87.5, 64.7, 41.4 and 16.2 kWh/m3, respectively, suggesting the last one as the most economical. Additionally, for the processes combined with the iron, biochemical oxygen demand/chemical oxygen demand (BOD5/COD) in the CIP solution was above 0.4, which indicated the conversion of non-biodegradable wastewater to biodegradable form. The total organic carbon (TOC) test was performed, and the mineralization percentage by the US/PS/H2O2/Fe2+ process was 82%. Studies conducted for evaluating the effect of scavengers also showed that both sulfate (SO4•−) and hydroxyl (•OH) radicals play an important role in the studied process.

Ultrasound accelerated near-edge functionalized heterogeneous graphene oxide sonocatalyst for surface optical bandwidth efficacy and in situ sonothermocatalysis

Ultrasound-accelerated optically active heterogeneous catalyst and sonochemical time driven thermodynamic dye catalysis.

CO2 adsorption and its visible-light-driven reduction using CuO synthesized by an eco-friendly sonochemical method

One alternative to mitigate the high CO2 concentration in the atmosphere is its conversion into value added-products or solar fuels by heterogeneous photocatalysis. However, in these reactions, the CO2 fixation remains a challenge due to the inert nature of greenhouse gas. Thus, it is necessary to propose materials that presented good performances in both processes: CO2 adsorption and its photocatalytic conversion to solar fuels. Copper oxide is a potential material that could exhibit high efficiencies for both processes if it is prepared by adequate synthesis methods. In this work, CuO was obtained by a sonochemical method using an eco-friendly surfactant (Na3C6H5O7), low sonochemical time (15 min) and low temperatures (80 °C). The materials were evaluated in a combined process that involves CO2 adsorption and its photocatalytic conversion to liquid fuels (CH3OH) under LED visible-light at 25 °C. CuO particles were characterized by X-ray powder diffraction, Scanning Electronic Microscopy, N2 physisorption, FTIR spectroscopy, Diffuse Reflectance Spectroscopy, and X-ray photoelectron spectroscopy. CuO pure showed the best efficiencies for CO2 adsorption: 318 mgCO₂ g−1 and CH3OH production: 3.7 μmol g-1 h-1, which was associated with it’s the high number of active sites. Bohem titrations were used to calculate the active: acid/basic sites in the samples, which results demonstrated a higher contribution of basic sites (2.4 mmol). These active sites favored the formation of monodentate bonds between CO2 and CuO, which promoted its photoconversion to solar fuels such as CH3OH. Additionally, CuO/Cu(OH)2 mixtures with the high surface area were identified at higher concentrations of Na3C6H5O7. However, these mixtures did not show high efficiencies for both processes. A mechanism of combined CO2 adsorption and its photocatalytic conversion to methanol under visible light was proposed. The stability and recyclability of CuO as CO2 adsorbent and as a photocatalyst was demonstrated after three consecutive cycles without compromise its efficiency in the combined process.

Sonochemical time standardization for bioactive materials used in periimplantar defects filling

The aim of this study was determinate the best sonochemical time in order to obtain better bone characteristics when a bioactive material (Biogran) is used in the filling periimplantar defects. In this study, 32 rats were submitted to surgical proceedings to create a periimplantar defect that was filled with Biogran receiving different sonochemical times: 15 (G1), 30 (G2), 45 (G3) or 90 min (G4). The biomaterial was characterized through X-ray diffraction and scanning electron microscopy (SEM). In vivo analysis was performed through micro CT, laser confocal microscopy, immunohistochemistry and evaluation of bone cytoarchitecture through hematoxylin and eosin (HE) staining. The data were submitted to statistical testing, considering a significance level of p < 0.05. Rx diffraction of pure bioglass showed that it is predominantly amorphous; otherwise, there are small peaks at 23° and 31°. SEM shows that the longer the sonochemical time, the less edges the biomaterial will present. Within the groups, G1 and G2 showed the best quantity and quality by micro CT (p > 0.05). The best bone turnover result was found in G1 and G2, otherwise the better results were related to neoformed bone area, bone mineral apposition rate and bone implant contact to G1 (p < 0.05). G1 had the best results in terms of bone cytoarchitectural evaluation and immunohistochemistry. It is possible to conclude that Biogran that received 15 min of sonochemical treatment (G1) presented periimplantar bone repair with the best extracellular matrix properties, including the best quality and quantity of vital bone.

Ga-doped ZnO nanoparticles synthesized by sonochemical-assisted process

In this work, the experimental work has been conducted on the synthesis of Gallium (Ga)- doped zinc oxide (ZnO) nanoparticles with different doping concentration (0-5% at.) via sonochemical process. The precursors of Ga-doped ZnO nanoparticle were sourced by zinc acetate dehydrate and gallium (III) nitrate hydrate, respectively. Ammonia (NH3) was chosen as a precipitating agent in sonochemical process. The sonochemical time was operated for 10 min by a direct-immersion ultrasonic horn using Sonic model VCX 750 (750W, 20 KHz). Structural properties and morphologies were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that Ga doped ZnO powder after the synthesis were obtained in ultrafine structure that different form with pure ZnO. XRD analysis revealed that the pattern of Ga doped ZnO powder showed good crystallinity with the wurtzite structure due to the preferred orientation direction and crystallization. Ga doping concentration plays a key role in significant change of ZnO structures.

Synthesis of flower-like ZnO nanostructures by sonochemical route and their photocatalytic activity

In this study, the flower-like ZnO nanostructures have been fabricated using zinc chloride and potassium hydroxide as precursors by sonochemical technique. The as-prepared ZnO nanostructures were characterized by SEM, XRD, Fourier Transform Infrared Spectroscopy (FTIR), Raman spectra and UV–vis spectroscopy. The results indicated that the synthesized zinc oxide posses a flower shape with diameters in the range of 4–6μm. Meanwhile, every single flower is composed of needle-like crystals of 200–300nm in diameter irradiated from the center. The morphologies of the obtained product at different sonochemical time were experimentally studied. The formation mechanism is discussed in detail. Additionally, photocatalytic activity of the prepared ZnO sample was evaluated by the degradation of methylene blue under UV irradiation.

One-pot sonochemical preparation of fluorographene and selective tuning of its fluorine coverage

Fluorographene (FG), which inherits the properties of graphene and fluorographite (FGi), holds great promise for applications in high-performance materials and devices, including lubricants, nanocomposites, batteries, and nanoelectronics. However, challenges for realizing large-scale preparation and little knowledge concerning FG's physicochemical properties hinder its practical applications. Here, a novel and feasible method is developed to prepare FG through a simple sonochemical exfoliation process in N-methyl-2-pyrrolidone (NMP). Interestingly, FG at a high concentration in NMP displays dramatic stability without any additional stabilizer or modifier, and the C/F ratio of FG can be facilely tuned just by adjusting the sonochemical time. Furthermore, the electrochemical and thermal properties of the prepared FG have been systematically investigated and exhibited regularity with variation of fluorine coverage. On the other hand, based on the solubility of FG in various solvents, a possible dispersion mechanism is proposed to guide FG's further applications in films or polymer-based composites as a mechanical reinforcement.

Investigating the potential of using acoustic frequency on the degradation of linear alkylbenzen sulfonates from aqueous solution

The effectiveness of using acoustical (sonochemical) reactor for degradation of linear alkylbenzen sulfonate (LAS) from aqueous solution was investigated. LASs are anionic surfactants, found in relatively high amounts in domestic and industrial wastewaters. In this study, experiments on LAS solution were performed using methylene blue active substances (MBAS) method. The effectiveness of acoustical processor reactor for LAS degradation is evaluated with emphasis on the effect of treatment time and initial LAS concentration. Experiments were performed at initial concentrations of 0.2, 0.5, 0.8 and 1.0 mg/L, acoustic frequency of 130 kHz, applied power of 500 W and temperature of 18 °C∼20 °C. At the conditions involved, LAS degradation was found to increase with increasing sonochemical time. In addition, as the concentration increased, the LAS degradation rate decreased in the acoustical processor reactor.

Synthesis of mesoporous amorphous MnO 2 from SBA-15 via surface modification and ultrasonic waves

Ultrasonic waves in combination with nanocasting method have been successfully used in preparation of mesoporous amorphous MnO 2 from SBA-15. Modification of the intrachannel surfaces of SBA-15 with amino making them hydrophilic ensures precursor KMnO 4 to readily penetrate the pore channels. Moreover, the modification changes the surface reactivity, enabling the formation of MnO 2 inside the pores of SBA-15 by the sonochemical reduction of metal ions. The texture/structures of the resultant materials were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform-infrared (FT-IR) spectroscopy, Raman scattering and nitrogen adsorption/desorption measurements. The loading percentage can be controlled via sonochemical time and almost 76% of the mesoporous volume of the SBA-15 host was finally occupied by nanoparticles MnO 2. The novelty of presented approach is 2-fold: a new synthetic concept – a simple and effective method to allow practically a high filling of the pores for fabricating mesoporous metal oxide; and the morphology of the resultant is easier to control, for the formation of metal oxide was completed during the sonochemical process instead of during heat treatment.