Combination Of Ultrasonic Irradiation Research Articles

Ultrasound enhanced destruction of tetracycline hydrochloride with peroxydisulfate oxidation over FeS/NBC catalyst: Governing factors, strengthening mechanism and degradation pathway

In this study, FeS/N-doped biochar (NBC) derived from the co-pyrolysis of birch sawdust and Mohr's salt was applied to evaluate the efficiency of catalyzed peroxydisulfate (PDS) oxidation for tetracycline (TC) degradation. It is found that the combination of ultrasonic irradiation can distinctly enhance the removal of TC. This study investigated the effects of control factors such as PDS dose, solution pH, ultrasonic power, and frequency on TC degradation. Within the applied ultrasound intensity range, TC degradation increases with increasing frequency and power. However, excessive power can lead to a reduced efficiency. Under the optimized experimental conditions, the observed reaction kinetic constant of TC degradation increased from 0.0251 to 0.0474 min−1, with an increase of 89%. The removal ratio of TC also increased from ∼85% to ∼99% and the mineralization level from 45% to 64% within 90 min. Through the decomposition testing of PDS, reaction stoichiometric efficiency calculation, and electron paramagnetic resonance experiments, it is shown that the increase in TC degradation of the ultrasound-assisted FeS/NBC-PDS system was attributed to the increase in PDS decomposition and utilization, as well as the increase in SO4•− concentration. The radical quenching experiments showed that SO4•−, •OH, and O2•− radicals were the dominant active species in TC degradation. TC degradation pathways were speculated according to intermediates from HPLC-MS analysis. The test of simulated actual samples showed that dissolved organic matter, metal ions, and anions in waters can undercut the TC degradation in FeS/NBC-PDS system, but ultrasound can significantly reduce the negative impact of these factors.

Influence of micron-sized air bubbles on sonochemical reactions in aqueous solutions exposed to combined ultrasonic irradiation and aeration processes

Sonochemical reactors are promising for wastewater treatment applications. However, the combination of ultrasonic irradiation and aeration processes raises questions regarding the extent to which entrained air bubbles influence sonochemistry. In this study, the effect of micron-sized air bubbles (20 and 70 µm, 0.1–5.0 vol%) on sonochemical activity, based on KI dosimetry, was tested in a horn-type reactor (20 kHz). Bubbles were generated using the pressurization–depressurization method. The results showed that low bubble concentrations increased sonochemical yields but higher concentrations tended to decrease the yields. Compared with the bubble-free case, 20-μm bubbles enhanced sonochemistry at all concentrations, while 70-μm bubbles inhibited sonochemistry at the highest concentration (5.0 vol%). Two regimes, acoustic attenuation and nucleus introduction, were identified as inhibiting and enhancing sonochemical effects, respectively, and their dependence on bubble characteristics was examined. These results are significant as investigation into these regimes will allow a deeper understanding of the key factors controlling sonochemistry in the presence of micron-sized air bubbles and could be used to design sonoreactors equipped with aerators.

Solvent influence on the formation of ZnO nanoparticles by sonochemical technique and evaluation of UV-blocking efficiency

A highly efficient UV-shielding (>98.0%) ZnO nanoparticles (ZnO-A) have been synthesised sonochemically from [Zn(acac)2·H2O] and NaOH in ethanol-water mixture without any stabiliser or capping agent in a one-step process. In contrast, a combination of ultrasonic irradiation and calcination afforded pure ZnO nanoparticles (ZnO-B) with poor UV-blocking efficiency using ethanol as a solvent. A mechanism has been proposed indicating that water is the driving force to yield ZnO nanoparticles in a single step. X-ray diffraction (XRD) confirms hexagonal wurtzite structure for both products. UV–Visible (UV–Vis) spectra exhibit a broad peak at 355 nm and 360 nm corresponding to a bandgap of ∼3.49 eV and ∼3.44 eV for ZnO-A and ZnO-B. ZnO-A displays photoluminescence (PL) with violet (426 nm), blue (456 nm), and green (561 nm) emissions, while ZnO-B shows violet (428 nm) and blue (458 nm) emissions only. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis reveal petal-like morphology for ZnO-A, whilst FESEM of ZnO-B shows aggregated nanostructures.

A simple and efficient ultrasonic-assisted electrochemical approach for scalable production of nitrogen-doped TiO2 nanocrystals

In this study, we report a facile and effective approach for large-scale production of nitrogen-doped TiO2 nanocrystals (UNTs) by a combination of ultrasonic irradiation and electrochemistry at room temperature using NH4NO3 electrolyte as the nitrogen source. The as-prepared UNTs were then characterized by x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV–visible diffuse reflectance spectroscopy. The results indicated that the nitrogen content of UNTs reached 9.3% and bandgap energy of 2.62 eV, thus gave the high photocatalytic degradation of methylene blue under visible light irradiation. The mechanism for the formation of UNTs by ultrasonic-assisted electrochemical approach was also proposed.

MiR‑378 in combination with ultrasonic irradiation and SonoVue microbubbles transfection inhibits hepatoma cell growth.

Ultrasonic microbubbles in combination with microRNA (miRNAs/miRs) exhibited promising effects on cancer treatments. The aim was to investigate the role of miR-378 in hepatoma cells and the efficiency of it in combination with ultrasonic irradiation and SonoVue® microbubbles method for cell transfection. HuH-7, Hep3B and SK-Hep1 cells were transfected with an miR-378 mimic using only Lipofectamine® 3000 or combined with SonoVue microbubbles and ultrasonic irradiation at 0.5 W/cm2 for 30 sec. mRNAs and protein levels of Cyclin D1, Bcl-2, Bax, Akt, p53 and Survivin were detected by reverse transcription-quantitative PCR and western blotting, respectively. Cell survival rate, proliferation, cell cycle and apoptosis were determined by Cell Counting Kit-8, cell double cytochemical staining and flow cytometry, respectively. It was found that using a combination of ultrasonic irradiation and the SonoVue microbubbles method increased the effectiveness of miR-378 transfection into hepatocellular carcinoma (HCC) cells, and increased the inhibition of cell survival and proliferation. Moreover, miR-378 increased the rate of apoptosis and upregulated the expression of Bax and p53, and suppressed the cell cycle and downregulated the expression of Cyclin D1, Bcl-2, Akt, β-catenin and Survivin much more effectively in the HCC cell line by applying the combined method. Thus, miR-378 was shown to be a suppressive factor to reduce proliferation and increase apoptosis in HCC cells. Additionally, the combination of ultrasonic irradiation and SonoVue microbubbles method was more efficient in the transfection of miRNA.

Studied on sonocatalytic degradation of Rhodamine B in aqueous solution.

This paper describes experimental results of degradation of Rhodamine B (RB) by vortex scattering ultrasound in aqueous solution. Vortices are produced by a high-speed agitator. The effects of different factors on the degradation of RB solution were studied, such as different reaction container, the initial concentration of RB, stirring speed and ultrasonic frequencies. Ultraviolet-visible spectrophotometer (UV) was used to measure the absorbance value of RB to assess degradation rate. The optimal experimental condition was three-necked bottle, stirring speed of 700 r/min, initial concentration of 10 mg/L and ultrasonic frequency of 40 kHz. The optimal degradation rate of RB can reach 98% within one hour. The combination of ultrasonic irradiation and mechanical stirring was discovered that can degrade the RB efficiently in aqueous solution. The investigation of mechanism demonstrates that the cavitation bubbles produced by agitation play a major role in promoting degradation. COMSOL Multiphysics (Version 5.3a) software was used to simulate this process. And the method of combination of ultrasonic irradiation and mechanical stirring has also been shown to be effective in degrading methylene blue, bromophenol blue and Congo red. So the combination of ultrasonic irradiation and mechanical stirring can be used as an option for treating organic wastewater in the future. This study established a new way to degrade other organic pollutants.

Kinetic of the degradation of sulfanilic acid azochromotrop (SPADNS) by Fenton process coupled with ultrasonic irradiation or L-cysteine acceleration

Abstract The degradation kinetics of sulfanilic acid azochromotrop (SPADNS) in aqueous phase by Fenton process has been examined. The effect of pH, hydrogen peroxide [H2O2], ferrous ion [Fe2＋], molar ratio of [H2O2]/[Fe2＋] and SPADNS concentration [SPADNS] have been estimated systematically. The optimum reaction conditions were found to be pH = 3.5, [H2O2] = 1.7 × 10−3 M, [Fe2＋] =1.0 × 10−4 M for [SPADNS] = 1.0 × 10−4 M. Under these situations, 100% decolorization efficiency of aqueous SPAND solution was accomplished after 60 min of reaction. Also, the influence diverse inorganic anions (such as Cl − , NO 3 − , HCO 3 − , etc. present in contaminated water) on the degradation efficiency of Fenton oxidation were investigated. A combination of ultrasonic irradiation and Fenton process (US/Fenton) has been used to evaluate the effect of azo bond loading factor ( L azo bond ; 0.25 to 1) on SPANDS degradation kinetic rates. The results show that the oxidation of Fenton could be enhanced by ultrasonic irradiation. For example, the color removal for L azo bond 0.25, using Fenton and US-Fenton processes were 84.6% and 92.7% after an hour of oxidation reaction, respectively. While in the same period of time, there was no significant increment for TOC removal of chemical oxygen demand (COD) loading factor L COD 0.25, using Fenton and US-Fenton processes, which were 44.3% and 46.0%, respectively. This may be attributed to the formation of molecules with high stability against hydroxyl free radical. Also, this study found there was no significant effect on SPANDS degradation with the introduction of L-cysteine (Cys) to Fenton system. Three kinetic models (first-order, the second-order, and Behnajady–Modirshahla–Ghanbary) were evaluated and the Behnajady–Modirshahla–Ghanbary kinetic model was found to be the best model representing the experimental kinetic data of SPADNS.

Ag modified LaMnO3 nanoparticles for methylene blue degradation via photosonocatalytic activities

Catalyst incorporating Ag nanoparticles with LaMnO3 nanoparticles have been successfully synthesized using the co-precipitation method. The characteristics of the materials are characterized using x-ray diffraction (XRD), UV-Visible spectrometer and thermogravimetric analysis (TGA). The results show that the Ag/LaMnO3 composite show orthorhombic structure of the LaMnO3 nanoparticle and the cubic structure of Ag nanoparticle. The Ag/LaMnO3 composite shows better photosonocatalytic activities of methylene blue (MB) than LaMnO3 nanoparticle under the combination of ultrasonic irradiation and visible light irradiation. Ag can be used as an electron capture in the photosonocatalytic process, because Ag can capture the electron transport along LaMnO3 nanoparticles leading to a high recombination rate of electrons and holes.

Novel approaches based on ultrasound for treatment of wastewater containing potassium ferrocyanide

Industrial wastewaters containing biorefractory compounds like cyanide offer significant environmental problems attributed to the fact that the conventional methods have limited effectiveness and hence developing efficient treatment approaches is an important requirement. The present work investigates the use of novel treatment approach of ultrasound (US) combined with advanced oxidation techniques for the degradation of potassium ferrocyanide (KFC) for the first time. An ultrasonic bath equipped with longitudinal horn (1kW rated power and 25kHz frequency) has been used. The effect of initial pH (2–9) on the progress of degradation has been investigated initially and subsequently using the optimized pH, effect of addition of hydrogen peroxide (ratio of KFC:H2O2 varied over the range of 1:0.5–1:5) and TiO2 in the presence of H2O2 (1:1 ratio by weight of TiO2) as process intensifying approach has been studied. Combination of ultrasonic irradiation with ozone (O3) (100–400mg/h) and ultraviolet irradiation (UV) has also been investigated. Use of combination of US with H2O2, H2O2+TiO2 and ozone resulted in extent of KFC degradation as 54.2%, 74.82% and 82.41% respectively. Combination of US with both UV and ozone was established to be the best approach yielding 92.47% degradation. The study also focused on establishing kinetic rate constants for all the treatment approaches which revealed that all the approaches followed first order kinetic mechanism with higher rate constants for the combination approaches. Overall, it has been conclusively established that ultrasound based combined treatment schemes are very effective for the treatment of KFC containing wastewaters.

Effects of solvent addition and ultrasound waves on viscosity reduction of residue fuel oil

In this work, the influence of temperature, solvent concentration and ultrasonic irradiation time on viscosity reduction of residue fuel oil (RFO) are studied. The main feature of this research is using ultrasonic irradiation at low frequency of 24kHz and power of 280W, for viscosity reduction and quality enhancement of RFO. Kinematic viscosity of RFO was found to decrease from 4940 cSt to 2679 cSt due to application of ultrasonic irradiation for 5min at initial temperature of 20°C. Results showed that combination of ultrasonic irradiation with solvent led to intensified decrease of viscosity and API gravity promotion. The maximum reduction of viscosity (at 133cSt) occurred in ultrasonic irradiation time of 5min, temperature of 50°C and acetonitrile loading of 5% by volume. API gravity, distillation and FT-IR analyses revealed that ultrasonic waves have an effective role in cracking and lightening of the examined heavy fuel oil. The measured results including 336 data points of eighty-four samples were analyzed by the feed-forward back propagation of artificial neural network (ANN). The relative importance percent of input variables was calculated and it was found that ultrasonic irradiation time and acetonitrile concentration has maximum and minimum relative importance in viscosity reduction, respectively.

Combination of ultrasonic irradiation with ionic liquid pretreatment for enzymatic hydrolysis of rice straw

The application of ultrasonic irradiation and ionic liquids (ILs) in the degradation of rice straw under different processes of pretreatment and enzymatic hydrolysis was investigated. Various substrates for enzymatic hydrolysis by cellulase with and without ultrasound were as follows: untreated rice-straw powder (RS); RS treated by ILs of 1-ethyl-3-methylimidazolium ethylsulfate and trihexyl (tetradecyl) phosphonium decanoate with ultrasound at 300 W/(40 kHz, 28 kHz); RS treated by IL of choline hydroxide ([Ch][OH]) with ultrasound at 300 W/40 kHz (CHRS). In ultrasound-mediated enzymatic hydrolysis, the yield of total reducing sugar (TRS) converted from CHRS was up to 96.22% at 240 min and was greater than that from the other substrates; the TRS yield for CHRS with ultrasound was 19.5% greater than that without irradiation. Lignocellulosic biomass pretreated with [Ch][OH] showed the highest efficiency among the tested ILs, and ultrasound can be applied effectively in rice-straw pretreatment and enzymatic hydrolysis.

Combined of ultrasound irradiation with high hydrostatic pressure (US/HHP) as a new method to improve immobilization of dextranase onto alginate gel

In this research work, dextranase was immobilized onto calcium alginate beads by the combination of ultrasonic irradiation and high hydrostatic pressure (US/HHP) treatments. Effects of US/HHP treatments on loading efficiency and immobilization yield of dextranase enzyme onto calcium alginate beads were investigated. Furthermore, the activities of immobilized enzymes prepared with and without US/HHP treatments and that prepared with ultrasonic irradiation (US) and high hydrostatic pressure (HHP), as a function of pH, temperature, recyclability and enzyme kinetic parameters, were compared with that for free enzyme. The maximum loading efficiency and the immobilization yield were observed when the immobilized dextranase was prepared with US (40W at 25kHz for 15min) combined with HHP (400MPa for 15min), under which the loading efficiency and the immobilization yield increased by 88.92% and 80.86%, respectively, compared to immobilized enzymes prepared without US/HHP treatment. On the other hand, immobilized enzyme prepared with US/HHP treatment showed Vmax, KM, catalytic and specificity constants values higher than that for the immobilized enzyme prepared with HHP treatment, indicated that, this new US/HHP method improved the catalytic kinetics activity of immobilized dextranase at all the reaction conditions studied. Compared to immobilized enzyme prepared either with US or HHP, the immobilized enzymes prepared with US/HHP method exhibited a higher: pH optimum, optimal reaction temperature, thermal stability and recyclability, and lower activation energy, which, illustrating the effectiveness of the US/HHP method. These results indicated that, the combination of US and HHP treatments could be an effective method for improving the immobilization of enzymes in polymers.

Reductive dechlorination of polychlorinated biphenyls (PCBs) by ultrasound-assisted chemical process (UACP)

The dechlorination of aqueous polychlorinated biphenyls (PCBs) using the ultrasound-assisted chemical process (UACP), which is a combination of ultrasonic irradiation and radical generations using di-tert-butyl peroxide as a radical initiator and ferrous ion as a catalyst at moderate temperature in alkaline 2-propanol, was demonstrated with a high reduction of PCBs. A commercial PCB-containing compound, Aroclor 1260, was also decomposed with the removal efficiency of 97 % achieved within 3 h of UACP. The gas chromatograph was used as a quantitative method to measure the decomposition rate of PCBs. The competitive elimination among the ortho (2-position), meta (3-position), and para (4-position) chlorine atoms of PCB was also identified.

Ultrasonic irradiation on hydrolysis of magnesium hydride to enhance hydrogen generation

This paper describes the ultrasonic irradiation on the hydrolysis of magnesium hydride to enhance hydrogen generation; the effects of the ultrasonic frequency and the sample size on the hydrogen generation were mainly examined. In the experiments, three MgH 2 particle and nanofiber samples were soaked in distilled water and ultrasonically irradiated at frequencies of 28, 45, and 100 kHz. Then, the amount of hydrogen generated was measured. We found that the low frequency of ultrasonic irradiation and the relatively small sample size accelerated the hydrolysis reaction MgH 2 + 2H 2O = Mg(OH) 2 + 2H 2 + 277 kJ. In particular, the MgH 2 nanofibers exhibited the maximum hydrogen storage capacity of 14.4 mass% at room temperature at a frequency of 28 kHz (ultrasound irradiation). The results also experimentally validated that a combination of ultrasonic irradiation and MgH 2 hydrolysis is considerably effective for efficiently generating hydrogen without heating and adding any agent.

Effect of the Sonophotocatalytic Pretreatment on the Volume Reduction of Sewage Sludge and Enhanced Recovery of Methane and Phosphorus

In this study, the sonophotocatalytic process, i.e., combination of ultrasonic irradiation (US) and photocatalytic reaction, was proposed as a pretreatment process for the anaerobic digestion of organic sludge in order to drastically reduce the amount of sludge and promote the recovery of methane and phosphorus. Several series of experiments employing different techniques, i.e., sonophotocatalysis (SPC), US, photocatalysis (PC), and thermal treatment, were conducted by using a batch type apparatus. The results of the SPC treatment showed a decrease in sludge volume by about 50% and the synergetic effects of US and PC treatments which were clearly observed as increases in dissolved chemical oxygen demand of sludge filtrate and in phosphorus compounds dissolution from sludge particles. In the SPC process of sewage sludge, the photocatalytic reaction was enhanced by the sufficient disintegration of sludge flocks due to the US treatment. Any pretreatments applied promoted the anaerobic digestion process, however, there was little synergetic effect and the long time SPC treatment resulted in a decrease in the reaction rate.

Degradation of C.I. Acid Red 88 aqueous solution by combination of Fenton's reagent and ultrasound irradiation

AbstractBACKGROUND: Pollution caused by industrial wastewater has become a common problem for many countries. In particular, dye pollutions from industrial effluents disturb human health and ecological equilibrium. The discharge of highly colored synthetic dye effluents is aesthetically displeasing and can damage the receiving water body by impeding penetration of light. Azo dyes can be reduced to more hazardous intermediates on anaerobic conditions. Therefore, an effective and economic treatment of effluents containing a diversity of textile dyes has become a necessity for clean production technology for textile industries. Herein we wish to report the degradation of Acid Red 88 by the combination of Fenton's reagent and ultrasound irradiation.RESULTS: The results show that the combination of ultrasonic irradiation and Fenton's reagent is effective for the degradation of Acid Red 88 aqueous solution. Furthermore, it can achieve better results than either Fenton's reagent or ultrasound alone. The optimum conditions for the degradation of Acid Red 88 aqueous solution were 1.96 mmol L−1 H2O2, 0.108 mmol L−1 Fe2+, pH 3.0, and ultrasonic irradiation frequency of 40 kHz. A degradation efficiency of 98.6% was achieved within 135 min.CONCLUSION: We have provided an efficient and convenient procedure for the degradation of Acid Red 88 aqueous solution. In the present procedure, the azo linkage of Acid Red 88 is broken and some carbonyl compounds are formed, but the complete mineralization of dye cannot be achieved. Copyright © 2008 Society of Chemical Industry

Preparation of Fe-doped mixed crystal TiO 2 catalyst and investigation of its sonocatalytic activity during degradation of azo fuchsine under ultrasonic irradiation

In this work, Fe-doped mixed crystal TiO 2 powder as sonocatalyst was prepared by the sol–gel method and heat treatment, and a novel method combined with ultrasonic irradiation was propounded to degrade the organic polluted water. First, the Fe-doped mixed crystal TiO 2 powder was characterized by TG–DTA, XRD, and TEM techniques. Ultrasound was used as the irradiation source and the azo fuchsine was chose as the model compound. Then a series of degradation experiments was carried out in the presence of Fe-doped mixed crystal TiO 2 powder. Also, the degradation process and some influencing factors, such as irradiation time, doping Fe 3+ ion content, added amount of catalyst, and initial concentration of azo fuchsine solution, on the degradation were investigated by UV–vis spectra, ion chromatography, and HPLC. Through the degradation of azo fuchsine, it was found that the combination of ultrasonic irradiation and Fe-doped mixed crystal TiO 2 powder can completely degrade the azo fuchsine in aqueous solution. Because of the good degradation efficiency, this method may be an advisable choice for the treatments of non- or low-transparent wastewaters in the future.

Iron(II)-catalyzed enhancement of ultrasonic-induced degradation of diethylstilbestrol (DES)

The oxidation of the endocrine disruptor, diethylstilbestrol (DES) in aqueous media by ultrasound is significantly enhanced by Fe(II) catalyst. The observed enhancement is likely the result of increased levels of hydroxyl radicals from the iron-promoted reduction of the hydrogen peroxide produced during ultrasonic irradiation. The degradation is effective over a range of concentrations and is consistent with pseudo first-order kinetics. Relatively high concentrations of hydrogen peroxide, ∼450 mM, are present in solution under our experimental conditions after 1 h of ultrasonic irradiation (665 kHz). The concentration of H 2O 2 in solution decreased with the addition of Fe(II) along with an increase in the degradation of DES. Hydrogen peroxide alone does not appreciably degrade DES. Our results demonstrate ultrasonic-induced degradation of DES can be accelerated with the addition of Fe(II). The combination of ultrasonic irradiation and Fe(II)-promoted conversion of H 2O 2 to hydroxyl radical may provide a valuable strategy for the treatment of organic pollutants.

A novel practical method for the generation of dichlorocarbene by ultrasonic irradiation and phase-transfer catalysis

The generation of dichlorocarbene from chloroform can be promoted effectively by the combination of ultrasonic irradiation and phase-transfer catalysis. It seems to be a novel practical method for generating dichlorocarbene with shorter reaction time, better yield and less amount of catalyst.