Presence Of Ultrasonic Irradiation Research Articles

Implanting TiO2 @MoS2/BiVO4 nanocomposites via sonochemically assisted photoinduced charge carriers promotes highly efficient photocatalytic removal of tetracycline

In recent decades, antibiotics have been identified in the aquatic environment, raising serious concerns. This study demonstrates antibiotic degradation via a photocatalytic technique through novel TiO2 @MoS2/BiVO4 nanocomposites created using a simple hydrothermal method in the absence or presence of ultrasonic irradiation. Several approaches were applied to characterize the structural, morphological, electrical, and optical properties of the as-synthesized catalysts. It confirmed the successful heterostructure formation with superior properties compared to bare samples. Furthermore, tetracycline antibiotics were investigated for photocatalytic degradation. The results reveal that the TiO2 @ 2 M/8B (US) composite shows outperformance compared to other composites regarding photocatalytic activity toward tetracycline degradation. After five cycles, TiO2 @ 2 M/8B (US) and TiO2 @ 2 M/8B (NUS) exhibit sufficient stability for tetracycline degradation. Throughout the degradation process, superoxide and hydroxyl radicals were found to be the key active species. According to the results, TiO2 @ 2 M/8B (US) has much better catalytic activity than TiO2 @ 2 M/8B (NUS). The synergistic effect of ultrasonic irradiation and the TiO2 optical bandgap reduction by stacking BiVO4 and MoS2 is responsible for this remarkable photocatalytic improvement.

Improvements in azithromycin recrystallization using ultrasound for size reduction

The primary motive of the current work is to achieve smaller mean particle size with narrow size distribution that can enhance the bioavailability of azithromycin (ARZ), an essential requirement due to its poor water solubility. Recrystallization of ARZ was evaluated using cooling as well as antisolvent crystallization approaches in the presence of ultrasonic irradiation with detailed study into effect of different parameters such as ultrasonic power, time and temperature. Ultrasound assisted antisolvent crystallization at low temperatures (<10℃) yielded best size reduction up to 80% with narrower distribution and also gave better yield of the product, that too within 5 min of sonication. With scale up considerations, recirculation mode of operation was also evaluated which offered promising results for the size reduction. Images captured using optical microscope and SEM revealed a nearly uniform rod/plate-shaped geometry. Increase in amorphous nature of ARZ was confirmed based on XRD analysis. FTIR analysis showed no significant changes in the functional groups when compared to the original sample. Overall, the work demonstrated an improved reprocessing approach based on the use of ultrasound with insights into effect of operating parameters and effect of ultrasound on various characteristics.

Sounchemical synthesis of Graphene/nano hydroxyapatite composites for potential biomedical application

Graphene nanocrystalline hydroxyapatite composites (G/nHA) were prepared using a wet precipitation method with CaCl2 and Na2 HPO4 as the main material in the presence of ultrasonic irradiation. The calcium to phosphate ratio (Ca/P) was adjusted to be about 1.67 while the pH value kept at 9.5-10.5. The texture properties of the G/nHA composites were determined through series of characterization techniques. High-resolution Scanning Electron Microscopy (HR-SEM) and high-resolution Transmission electron microscope (HR-TEM) were employed to determine the particle size and structure morphology of composites. The Crystalline and molecular structure were checked using (XRD), Raman and (FTIR), while thermal decomposition behavior was reported by thermogravimetric analysis (TGA-DTA). Energy dispersive spectroscopy (EDAX) results revealed that the prepared nHA and G2nHA samples had a Ca/P ratio of 1.66 and 1.73 respectively which are nearly matching to previously reported value. FT-IR analysis identified functional groups and confirmed the results obtained from the X-ray diffraction data that the prepared powders were indeed composed of nanoscale hydroxyapatite. The results indicate that nHA successfully prepared through this method and the range of particles was found around nanoscale. The compression test indicates that even the addition of very small amount of Graphene sheets like structure into the crystalline matrix of nHA enhancing the mechanical properties of the prepared composites compared to the pure nHA.

Sonochemical versus reverse-precipitation synthesis of CuxO/Fe2O3/MoC nano-hybrid: removal of reactive dyes and evaluation of smartphone for colorimetric detection of organic dyes in water media.

In the present work, an ultrasound-assisted reverse-precipitation method was applied as a new approach for the synthesis of CuxO/Fe2O3/MoC. In the sonication method, a bath type sonicator as a simple, cost-effective, and low intensity sonicator was used. To determine the influence of ultrasonic waves on the morphology and application of nano-hybrid as nano-sorbent, it was also synthesized using the reverse precipitation method. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), transmission electron microscopy (TEM), Zeta-potential measurement, and vibrating sample magnetometer (VSM) techniques. The XRD analysis confirmed that the sono-synthesized sample has higher crystallinity than the conventional one and CuO/Cu2O/MoC/Fe2O3 phase was obtained under ultrasound. According to the TEM and FESEM, sono-synthesized nanoparticles were rod-like with a width and length of 3nm and 40nm, respectively. Also, a well-dispersed shape and uniform morphology of nanoparticles were obtained using sonication. In comparison with the conventional nano-hybrid, this structure results in more void and accessible sites for adsorption of pollutants. The efficiency of resulting nanoparticles in adsorption of reactive dyes as a model of the pollutant was evaluated by sorption and sono-sorption processes. The sono-synthesized sample removed the pollutants more efficient than the conventional sample. The removal efficiencies were about 99% for the removal of reactive dyes using the sono-synthesized sample and sono-sorption method. Besides, determining factors including pH, pollutant concentration, temperature, and contact time were optimized in the sono-sorption and sorption processes. A colorimetric method based on RGB value was used to determine dye concentration in aqueous media. The images were taken by a smartphone and analyzed by ImageJ software. The accuracy of RGB results was confirmed by a UV-Vis spectrophotometer. Graphical abstract The figures on the left side show the FESEM images of nano-sorbent synthesized in the presence of ultrasonic irradiation (US method) and the absence of it (MS method). A well-dispersed shape and uniform morphology of nanoparticles were obtained using sonication. The scheme on the right side illustrates the process of sono-sorption for the removal of dyes and determination of their concentration using the colorimetric method. A colorimetric method based on RGB value was used to determine dye concentration in aqueous media. The graph shows the removal efficiencies of RY84 onto nanosorbent. The removal efficiencies were about 99% for the removal of reactive dye using the sono-synthesized sample and sono-sorption method.

Surface modification of mild steel before acrylic resin coating by hybrid ZnO/GO nanostructures to improve the corrosion protection

The synergistic effect of ZnO and GO nanostructures on the surface modification of mild steel before the acrylic resin coating was studied. Firstly, the steel surface was pretreated in the presence of ultrasonic irradiation, and then ZnO nanostructures were synthesized by the cyclic voltammetry technique. GO nanosheets prepared by the modified hummer’s method were deposited on ZnO-containing surfaces using the electrophoretic deposition (EPD) technique. GO coatings with thicknesses of 2.84, 4.47 and 9.42μm were obtained by varying the EPD time, and the 4.47μm was found as the optimum value for the fabrication of hybrid ZnO/GO structures. All samples were then covered with a thin layer of acrylic resin (10μm) by the spin coating technique. The results indicated that the sample with underneath of hybrid ZnO/GO nanostructures shows significant improvement in anti-corrosion performance. In other words, Rp is increased from 150,000Ωcm2 (in the rein coated sample) to 380,000Ωcm2 (in the sample with hybrid nanostructures). The resulting surface has the potential to use as protective and glossy black coatings. The role of underneath nature, surface roughness, and molecular interactions between oxygen functional groups of ZnO, GO, resin, and the metal in the enhanced corrosion protection was illustrated.

Ultrasonic assisted synthesis of Ni3(VO4)2-reduced graphene oxide nanocomposite for potential use in electrochemical energy storage.

In the present study, Ni3(VO4)2-reduced graphene oxide (NV/RGO) nanocomposite was synthesized for energy storage purpose. To this end, a mixture containing RGO nanosheets, Ni (CH3COOH)2 and Na3VO4 mixture was prepared under probe-type ultrasonic irradiation with frequency of 20KHz and the optimized power of 100W. The Raman and energy-dispersive X-ray spectroscopies confirmed the presence of RGO nanosheets, nickel and vanadium elements in the NV/RGO, respectively. In addition, field emission-scanning electron microscopy (FESEM) data showed the formation of the NV nanoparticles on the RGO nanosheets. NV/RGO nanocomposite was pasted on nickel foam (NF) and its performance was investigated in energy storage using a three-electrode cell containing 6M KOH. In cyclic voltammogram of NV/RGO/NF, redox peaks for Ni (II)/Ni (III) with intensities higher than that for NV/NF were observed which confirms the synergistic effect of RGO on the performance of NV. Chronopotentiometry data revealed that the NV/RGO/NF electrode exhibits high capacity of 117.22mAhg-1 at 2Ag-1. Electrochemical impedance spectroscopy also demonstrated an improvement in the electrical conductivity and electrochemical behavior of NV/RGO/NF nanocomposite compared to the RGO/NF and NV/NF. Furthermore, NV/RGO/NF electrode reserved about 88% of its initial capacity after 1000th potential cycle at 50mVs-1. Overall, the results of our study suggest that the NV/RGO nanocomposite prepared in the presence of ultrasonic irradiation might be regarded as a suitable active material for energy storage systems.

One-pot co-precipitation of copper–manganese–zinc oxide catalysts for the oxidation of CO and SO2 in the presence of ultrasonic irradiation

This paper studies the effect of addition of Zn and ultrasound-assisted co-precipitation on Cu-Mn oxide catalysts for the oxidation of CO. Cu-Mn-Zn oxide catalysts were synthesised at different molar ratios and characterised and evaluated for CO oxidation performance. Scanning electron microscopy (SEM) imaging showed that the morphologies and textural properties of the catalysts were markedly affected by the different synthesis conditions, notably the formation of different geometries of various sizes depending on the Zn loading used. Characterisation results also revealed that both the addition of Zn and the use of ultrasound-assisted synthesis improved the dispersion of metal constituents in the mixed oxide phase, evident from the lower peak intensity and smaller crystallite sizes and more dispersed particles as seen in SEM imaging. Gas adsorption results revealed that Zn loading influences the porosity and adsorption capability of the catalyst. Zn-loaded samples exhibited a H3 hysteresis loop, which suggests the presence of slit-like pores. Temperature-programmed reduction results indicate that sonicated samples exhibit improved reduction capabilities which can increase overall catalytic activity. Results showed that Cu/Mn/Zn = 2:1:0.5 displayed the highest activity, showing 76.0% and 82.8% for CO and SO2 at 130 °C, respectively. This work has confirmed that the addition of 0.5 molar ratio of Zn and the presence of ultrasonic treatment during the catalyst synthesis have improved the overall catalytic performance, while further addition in Zn concentrations resulted in an adverse effect on the catalyst.

The effect of ultrasonic irradiation on the morphology of NiO/Co3O4 nanocomposite and its application to the simultaneous electrochemical determination of droxidopa and carbidopa

The present work deals with the preparation of NiO/Co3O4 nanocomposites in presence of ultrasonic irradiation, and its use in electrochemical determination of Parkinson’s drugs. NiO/Co3O4 nanocomposites are prepared using ultrasound assisted method. The impact of ultrasonic irradiation power (0, 75, 150, 300 and 600 W) on the structure and morphology of NiO/Co3O4 nanocomposites was investigated. Various particle morphologies were attained because of the existence of ultrasonic irradiation. The nanoparticles’ structure exhibited more uniformity whilst the particles sizes and nanoparticle accumulation was reduced when ultrasonic irradiation power was increased. The NiO/Co3O4 nanocomposite was determined via X-ray diffraction, scanning electron microscopy i.e. SEM as well as energy dispersion X-ray spectroscopy (EDX). Drop casting NiO/Co3O4 nanocomposites suspension on glassy carbon electrode was employed to fabricate the modified glassy carbon electrode (NiO/Co3O4/GCE). The electrochemical studies on the NiO/Co3O4 nanocomposite towards droxidopa and carbidopa were experimented via cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV). The CV examinations displayed increased catalytic behavior of droxidopa because of synergistic impact of the nanocomposite that was bolstered through enhanced material surface roughness. By using differential pulse voltammetry, the droxidopa detection limit and linear range was determined as 0.01 μM and 0.1–500.0 μM, respectively. Also, the adjusted electrode was implemented to ascertain droxidopa in the presence of carbidopa by differential pulse voltammetry. This sensor exhibited long term reproducibility and stability. Droxidopa and carbidopa quantification within biological specimens of fluids i.e. human urine and serum were conducted to validate the suitability in the application of this sensor.

Synthesis of MoS2 nanoparticle deposited graphene/mesoporous MnOx nanocomposite for high performance super capacitor application

The present study deal with the fabrication of low cost nanocomposite based electrodes based on Nickel foam binder free substrate for supercapacitor applications. The composition of nanocomposite is molybdenum sulphide nanoparticle/graphene coated on mesoporous manganese oxide. The first step is to involve the preparation of mesoporous manganese oxide by non-ionic surfactant assisted method. In the second stage is to deposit the reduced graphene on mesoporous manganese oxide in the presence of ultrasonic irradiation followed by addition of known quantity of commercial MoS2 nanopowder (particle size below 90 nm). The manganese oxide based nanocomposite is showing porous architecture with graphene sheet formation together with MoS2 nanoparticle deposition. N2 adsorption-desorption Isotherm curves for MoS2 nanoparticle (NP) modified graphene oxide/meso-MnO2 and pure meso-MnO2 displayed type IV isotherm with improved surface area values. The reduced graphene oxide (graphene) and MoS2 exist in the form of glassy flaky morphology as well as tubular/needle shapes are obtained after the deposition process in the final nanocomposite. The orderly arranged and anchored nano-sized mesoporous manganese oxide nanocomposites are showed increased specific capacitance (up to 527, 727 and 1160 F/g) and continuous cyclic stability.

Investigation on the electrochemical performance of hausmannite Mn3O4 nanoparticles by ultrasonic irradiation assisted co-precipitation method for supercapacitor electrodes

ABSTRACTSpinel type manganese oxide (Mn3O4) nanoparticles were synthesized by ultrasonic irradiation assisted co-precipitation method using PEG and NaOH. The formation of tetragonal hausmannite phase (Mn3O4) with spinel structure was confirmed from XRD and FTIR studies. The average crystallite size of Mn3O4 nanoparticles was determined from Scherrer formula (39.9 nm) and Williamson–Hall relation (36.5 nm). The presence of elements, the overall oxidation state of manganese (Mn2+, Mn3+ and Mn4+) and chemical composition of these nanoparticles were determined from Mn 2p, Mn 3s and O 1s spectra using XPS. The spherically shaped morphology of these nanoparticles was analysed by SEM. The expected chemical composition of Mn3O4 nanoparticles was analysed by EDS. The electrochemical performance of these Mn3O4 nanoparticles was studied by CV, CP and AC impedance analysis. The maximum specific capacitance of Mn3O4 nanoparticles was found to be 296 F/g at a current density of 1 A/g2. Nyquist plot shows lower value of resistance that indicates the good electrical conductivity of the Mn3O4 electrode, which accounts for the improved electrochemical performance of the supercapacitors. Hence, the use of surfactant and the presence of ultrasonic irradiation in the synthesis process plays a dominant role in the electrochemical performance of Mn3O4 supercapacitors.

Ultrasound assisted synthesis of WO3-ZnO nanocomposites for brilliant blue dye degradation

The present work deals with the preparation of WO3 and WO3-ZnO nanocomposites in presence of ultrasonic irradiation, and its use in the sonocatalytic degradation of brilliant blue dye. WO3-ZnO nanocomposite is prepared using one step in-situ ultrasound assisted method. The successfully prepared WO3 and WO3-ZnO nanocomposites were characterized using different characterization techniques such as XRD, Raman, BET, FE-SEM and EDS. The XRD pattern reveals that the formation of monoclinic and hexagonal crystal structures of WO3 and ZnO respectively. BET study shows that WO3-ZnO nanocomposite have maximum surface area than that of the WO3. EDS study confirms the formation of WO3-ZnO nanocomposites. Further the use of the prepared WO3 and WO3-ZnO nanocomposites as a sonocatalyst for the degradation of brilliant blue dye. The rate constant (k) was evaluated as a function of the initial concentration of brilliant blue dye. It is found that WO3-ZnO nanocomposites exhibits maximum sonocatalytic activity as compared to WO3 photocatalyst.

Fast sonochemically-assisted synthesis of pure and doped zinc sulfide quantum dots and their applicability in organic dye removal from aqueous media

In this research, a sono-assisted chemical precipitation method was developed for a quick and efficient water-based synthesis of zinc sulfide (ZnS) quantum dots (QDs), in room temperature. ZnS QDs as pure and doped with some transition metal ions (such as Cu2+, Mn2+, Ag+) were prepared in the presence of l-cysteine, as capping agent. In comparison with the previous conventional methods, applying the ultrasonic irradiation provides a significant decrease in the reaction time. In comparison with previous reported conventional chemical QD synthesis methods, the required time for a complete synthesis in the presence of ultrasonic irradiations was significantly reduced to a period as short as 15 min, in a temperature of 40 °C. The sono-synthesized QDs were characterized with various techniques such as colorimetry, UV–Vis absorption spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). A broad absorption band between 270 and 290 nm was observed for colloidal ZnS QDs with the optical band gap larger than 3.68 eV. From the XRD and TEM results, the average particle size below 5 nm was estimated for the prepared QDs. After characterization, the samples were employed as nanophotocatalysts during a UV-derivate photocatalytic process for the degradation of Victoria blue R (VBR), as a pollutant dye. To obtain the optimal operating conditions, the influence of the affecting parameters such as the initial pH of the dye solution, irradiation time, initial dye concentration, type, electrolyte salt concentration and dosage of the nanophotocatalyst samples on the degradation efficiency (DE % was comprehensively studied, all in batch mode. Taking the optimum conditions into account, the maximum removal of VBR dye (>95%) can be obtained by spectrophotometric measurements at alkaline pH of 10.5, in the presence of low amounts of QDs (3 mg) and after 30 min of being exposed to UV irradiations. The results demonstrate that despite the removal of VBR, the QDs prepared by sonochemically method can be reused for at least six more times; without a significant decrease in their photocatalytic properties.

Development of an electrochemical process for production of nano-copper oxides: Agglomeration kinetics modeling

The main objective of this study was the development of a simple, clean, and industrial applicable electrochemical process for production of high pure nano-copper oxides from mining and industrial resources (e.g., ore, spent, slag and wastewater). To conduct the proposed process, a special set up containing an electrochemical cell in an ultrasonic system (28 kHz and 160 W) was proposed. Accordingly, using this set up and applying appropriate voltage (≈ 5 V) at 25 °C, in the presence of N2 gas, the simultaneous anode dissolution and nano-copper oxides formation (≈ 24 nm) can be occurred, rapidly (less than 45 min). Then, the effect of N2 gas and free radicals generated by ultrasonic irradiation was studied. The results showed, in the absence of ultrasonic irradiation and N2, an increase of electrolyte pH from 6.42 to 10.92, a decrease of electrolyte Eh from 285 mV to −1.14 V, and formation of copper nanoparticles. While, in the presence of ultrasonic and N2, the CuO nanoparticles were formed due to presence of H2O2 generated by interaction of free radicals. Moreover, a novel method for kinetics modeling of nanoparticles agglomeration was proposed according to distributed activation energy model and Arrhenius parameters variation. The results showed that, in the absence of ultrasonic irradiation, the nanoparticle agglomerates were firstly formed (interface controlled mechanism) and then, the diffusion of nanoparticle agglomerates was occurred (diffusion controlled mechanism). Therefore, the control of nanoparticles size and shape may be impossible without surfactant. Also, in the presence of ultrasonic irradiation, the whole of agglomeration process followed interface controlled mechanism. Therefore, using ultrasonic irradiation, the nanoparticles shape and size don’t change due to prevention of agglomerates diffusion.

Synthesis and characterization of cobalt sulfide nanoparticles by sonochemical method

Convenient and environmentally friendly synthesis of Co9S8/PVA, CoxSy/EG and CoxSy/3-MPA nanocomposites were carried out in the presence of ultrasonic irradiation by the liquid phase synthesis of the sonochemical method. For the synthesis, cobalt acetate tetrahydrate [Co(CH3COO)2·4H2O] and sodium sulfide (Na2S·9H2O) were used as a cobalt and sulfur precursor, respectively. Polyvinyl alcohol (PVA), ethylene glycol (EG) and 3-mercaptopropionic acid (3-MPA) were used as a capping agent and surfactant. The structural, optical properties and morphology of nanocomposites were characterized using X-ray diffractometer (XRD), Ultraviolet/Visible Spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The optical band gap of Co9S8/PVA is 1.81 eV and for CoxSy/EG is 2.42 eV, where the direct band gap of bulk cobalt sulfide is (0.78–0.9 eV). The wide band gap indicates that synthesised nanocomposites can be used in the fabrication of optical and photonic devices. The growth mechanisms of the Co9S8, CoS2 and Co3S4 nanoparticles were discussed by the reactions. The effects of sonication time and annealing temperature on the properties of the nanoparticles have been studied in detail.

Degradation of Acid Orange 7 by an ultrasound/ZnO-GAC/persulfate process

Abstract Granular activated carbon (GAC) supported ZnO catalyst (ZnO-GAC) was prepared to activate persulfate (PS) for the decolorization of Acid Orange 7 (AO7) in the presence of ultrasonic irradiation (US). The effects of initial pH, PS concentration, catalyst dosage, initial dye concentration, and reaction temperature were investigated. The results showed that the decolorization efficiency increased with the increase of catalyst dosage and temperature, but decreased with the increase of initial dye concentration and initial pH, and the optimal PS concentration for color removal was 0.5 g L−1. Radical quenching tests were performed by using ethanol, tert-butanol and phenol to verify the formation of sulfate radicals and hydroxyl radicals in the US/ZnO-GAC/PS process. Under the optimal conditions, 91.2% of decolorization was achieved and 83.1% of TOC was removed after 60 min treatment. Activated sludge inhibition tests were carried out to monitor the change of toxicity during the treatment of AO7 solution.

Sonochemical synthesis of Graphene-Ce-TiO2 and Graphene-Fe-TiO2 ternary hybrid photocatalyst nanocomposite and its application in degradation of crystal violet dye

The present work deals with the preparation of graphene oxide (GO) using Hummers-Offeman method in the presence of ultrasonic irradiations. Further loading of TiO2 photocatalyst on prepared GO was accomplished which is basically oxidation reduction reaction between graphene oxide and titanium isopropoxide that leads to the formation of graphene-TiO2 nanocomposite. Graphene-Ce-TiO2 and Graphene-Fe-TiO2 nanocomposites were prepared using one step in-situ ultrasound assisted method using GO, titanium isopropoxide, cerium nitrate, ferric nitrate, and 2-propanol. The successfully prepared graphene-TiO2, Graphene-Ce-TiO2, Graphene-Fe-TiO2 nanocomposites were then characterized using XRD, SEM and TEM analysis. The obtained XRD patterns clearly indicates the formation of anatase TiO2 on graphene nanosheets and it also indicates the presence of Ce and Fe in the Graphene-Ce-TiO2 and Graphene-Fe-TiO2 nanocomposite respectively. Further the use of the prepared nanocomposites as a photocatalyst have been studied for the degradation of crystal violet dye. The effect of various parameters such as catalyst doping, catalyst loading and initial concentration of dye on its degradation were studied. The effectiveness of the prepared catalysts were compared for the degradation of crystal violet dye. It has been observed that Graphene-Fe-TiO2 exhibits maximum photocatalytic activity compared to Graphene-Ce-TiO2 and Graphene-TiO2 nanocomposite photocatalyst.

Coupling of two centrifugeless ultrasound-assisted dispersive solid/liquid phase microextractions as a highly selective, clean, and efficient method for determination of ultra-trace amounts of non-steroidal anti-inflammatory drugs in complicated matrices

In this work, a new, simple, rapid, and environmentally friendly method with a high sample clean-up capability termed as centrifugeless ultrasound-assisted dispersive micro solid-phase extraction coupled with salting-out ultrasound-assisted liquid-liquid microextraction based on solidification of a floating organic droplet followed by high performance liquid chromatography is introduced for the first time. In this method, the three non-steroidal anti-inflammatory drugs diclofenac, ibuprofen, and mefenamic acid are first extracted based on an effective nanoadsorbent named as the layered double hydroxide-carbon nanotube nanohybrid. The first step provides a rapid and convenient way to separate the adsorbent from the sample matrix by a syringe nanofilter without additional centrifugation. In the next step, which is based upon the salting-out effect, after emulsification in the presence of ultrasonic irradiation, the phase separation is simply achieved through the salting-out phenomenon, and the extracting solvent is suspended on top of the sample solution. Under the optimal experimental conditions including the initial pH value of 6.0, 8.0 mg of the nanohybrid, 3 min ultrasonic time, 100 μL elution solvent (first step), secondary pH value of 3.0, 60 μL of 1-undecanol, 60 s ultrasonic time, and flow rate of 3 mL min−1 (second step), good responses were obtained for diclofenac, ibuprofen, and mefenamic acid in the concentration ranges of 0.8–2000, 0.8–2500, and 0.5–2000 ng mL−1, respectively, with low limits of detection ranging from 0.1 to 0.2 ng mL−1. The intra-day and inter-day precisions for the target analytes at the three concentration levels were in the ranges of 6.1–7.8% and 6.3–8.1%, respectively. The proposed method was also successfully applied to the biological and waste water samples, and excellent recoveries were obtained in the range of 92.9–103.1% even when the matrix was complex.

Synthesis and characterization of Fe0/TiO2 nano-composites for ultrasound assisted enhanced catalytic degradation of reactive black 5 in aqueous solutions

In the present study, nanocomposites (NCs) of zero valent iron nanoparticles (Fe0 NPs) and titanium dioxide nanoparticles (Fe0/TiO2 NCs) were prepared by coating Fe0 NPs onto the surface of TiO2 NPs through borohydride reduction of Fe(II) salt for the ultrasound assisted removal/ degradation of reactive black 5 (RB5) dye from aqueous solutions. Morphological and structural characterizations of the Fe0/TiO2 NCs were performed by FE-SEM, HR-TEM, XRD, XPS and Brunauer–Emmett–Teller (BET) method. The Fe0/TiO2 NCs exhibited highly efficient ultrasonic degradation/decolourization of RB5, compared to TiO2 NPs counterpart. In the presence of ultrasonic irradiation, 0.25g/L of Fe0/TiO2 NCs showed complete removal of 100mg/L RB5 dye within 10min of reaction. An increase in RB5 removal efficiency was obtained with decrease in initial concentration and solution pH, whereas it was decreased with decrease in the amount of Fe0/TiO2 NCs. The rate of RB5 degradation was in good agreement with the pseudo-first-order kinetic model. Higher RB5 removal efficiency was observed at a higher ultrasonic power level. Coexisting NO3− and SO42− ions had only a minor impact on the removal of RB5, whereas, CO32− ions considerably affected the% removal of RB5 using Fe0/TiO2 NCs. Regeneration/reusability experiments revealed that Fe0/TiO2 NCs could be reused efficiently up to 7th removal cycle without considerable loss of their original RB5 removal performance. Liquid chromatography–mass spectrometry (LC–MS) study, used for the detection of the RB5 degradation products showed that the degradation mechanism proceeds via the reductive cleavage of the azo linkage of the dye which produced 1-sulfonic, 2(4-aminobenzenesulfonyl) ethanol as the stable end product.

WITHDRAWN: Investigation on electrochemical performance of Hausmannite Mn3O4 nanoparticles by ultrasonic irradiation assisted co-precipitation method for supercapacitor electrodes

Spinel type-manganese oxide (Mn3O4) nanoparticles were synthesized by ultrasonic irradiation assisted co-precipitation method using PEG and NaOH. The formation of tetragonal hausmannite phase (Mn3O4) with spinel structure was confirmed from XRD and FTIR studies. The average crystallite size of Mn3O4 nanoparticles was determined from Scherrer formula (39.9 nm) and Williamson-Hall relation (36.5 nm). The presence of elements, overall oxidation state of manganese (Mn2+, Mn3+ and Mn4+) and chemical composition of these nanoparticles were determined from Mn 2p, Mn 3 s and O 1 s spectra using XPS. The spherical shaped morphology of these nanoparticles was analyzed by SEM. The expected chemical composition of Mn3O4 nanoparticles was analyzed by EDS. The electrochemical performance of these Mn3O4 nanoparticles was studied by CV, CP and AC impedance analysis. The maximum specific capacitance of Mn3O4 nanoparticles was found to be 296 F/g at a current density of 1 A/g2. Nyquist plot shows lower value of resistance that indicates the good electrical conductivity of the Mn3O4 electrode, which accounts for the improved electrochemical performance of the supercapacitors. Hence, the use of surfactant and presence of ultrasonic irradiation in the synthesis process plays a dominant role in the electrochemical performance of Mn3O4 supercapacitors.

Ultrasound assisted synthesis of performic acid in a continuous flow microstructured reactor

The present work establishes in depth study of ultrasound assisted preparation of performic acid (PFA) in a continuous flow microstructured reactor. The influence of various parameters viz. formic acid: hydrogen peroxide molar ratio, flow rate, temperature and catalyst loading on the PFA formation were studied in a continuous flow microstructured reactor. In a continuous microstructured reactor in the presence of ultrasonic irradiation, the formation of PFA was found to be dependent on the molar ratio of formic acid: hydrogen peroxide, flow rate of reactants, temperature and catalyst loading (Amberlite IR-120H). The optimized parameter values are 1:1M ratio, 50mL/h, 40°C and 471mg/cm3 respectively. Further, the performance of Amberlite IR-120H catalyst was evaluated for three successive cycles in continuous microstructured reactor. The performance of catalyst was found to be decreased with the usage of the catalyst and is attributed to neutralization of the sulfonic acid groups, catalyst shrinkage, or loss in pore sites. The experimental results revealed that, for an ultrasound assisted synthesis of PFA in continuous microstructured reactor the observed reaction time was even less than 10min. The observed intensification in the PFA synthesis process can be attributed to the intense collapse of the cavities formed at low temperature during ultrasonic irradiations, which further improved the heat and mass transfer rates with the formation of H2O2 during the reaction. The combined use of ultrasound and a continuous flow microstructured reactor has proved beneficial process of performic acid synthesis.