Effect Of Ultrasound Irradiation Research Articles

Effect of ultrasound irradiation on opto-structural properties and thermal behavior of Mg(OH)2 nanostructures

Effect of ultrasound irradiation on opto-structural properties and thermal behavior of Mg(OH)2 nanostructures

Sonodegradation of Sulfamethoxazole in Water Using Red Mud and Rice Husk Biochar Catalysis

This research evaluated the effectiveness of sulfamethoxazole (SMX) antibiotic degradation in aqueous solution using red mud and rice husk biochar (RMC) as catalytic material for ultrasound-supported degradation process. Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), and Energy-dispersive X-ray spectroscopy (EDX) were applied to study the characteristics of the catalytic material. The results demonstrated that the main components of RMC catalytic material are C, O, Si, and Fe elements with high weight percentage of 26.56%, 50.89%, 1.86% and 10.26%, respectively, and with high crystallized mix ratio. These are beneficial for SMX degradation reactions in water under the effect of ultrasound irradiation. The SMX degradation products were analyzed using High-performance liquid chromatography (HPLC). The effect of pH, contact time, initial concentration, and catalyst weight on degradation effectiveness were also investigated. The highest degradation efficiency of 75% at the treated rate of 15 mg SMX/g RMC was observed at pH = 3, contact time of 180 minutes, initial concentration of 20 mg SMX/L. This suggested a new solution to utilize the waste resources for waste treatment.

Effect of ultrasound irradiation on the growth of colloidal particles in resorcinol–formaldehyde solutions as precursors to porous adsorbents

Effect of ultrasound irradiation on the growth of colloidal particles in resorcinol–formaldehyde solutions as precursors to porous adsorbents

Influence of discontinuous on-line ultrasonic irradiation applied in ultrafiltration MBR systems over the physical-chemical and biological characteristics of the activated sludge

The influence of ultrasound (US) irradiation applied for membrane fouling control of a membrane bioreactor (MBR) over the physico-chemical and biological characteristics of the activated sludge was analysed. Three parallel MBR modules coupled to a sonicator which provided US irradiation at 20, 30 and 40kHz (fixed power 0.5W/L) were evaluated. The modules were fed with activated sludge from a conventional MBR. Particle size distribution (PSD), exopolysaccharide substances, soluble microbial products, biomass concentration and kinetic and stoichiometric parameters were assessed. The combination of 2s US pulses every 3min of filtration with 1min of backwashing with 3s of coarse bubble aeration achieved good results in membrane fouling control. A slight worsening of the effluent quality was observed for the sonicated MBR modules with respect to a conventional MBR, mainly for the 20kHz module, which showed the worst transmembrane pressure control. A slight activated sludge PSD displacement towards larger sizes was observed for all frequencies, but the characteristics of the activated sludge was not significantly altered, so the worsening of the effluent quality or membrane fouling were not related to the effect of US irradiation on biomass. Alteration in the biological activity was not relevant.

Proapoptotic effect of nonthermal pulsed ultrasound on prostate cancer cells in a nude mouse model.

Ultrasound (US) can induce cell injury, and we have previously reported that adjusting the pulse repetition frequency (PRF) of ultrasound output can induce prostate cancer cell destruction without causing a rise in the temperature of the irradiated area. In this study, we examined the mechanism of nonthermal ultrasound cell destruction, which was not fully clarified in our previous reports. In vitro, we evaluated postirradiation cells immediately after treatment and examined membrane disruption by proliferation assay, LDH assay, and apoptosis assay. In vivo, we injected mice with human LNCaP and PC-3 prostate cancer cells and evaluated the therapeutic effects of US irradiation by H-E staining and immunostaining. Proliferation assays showed inhibition at 3 h postirradiation independently of PRF and cell line (p < 0.05). Quantitative assessment of apoptosis/necrosis by flow cytometry showed widely varying results depending on cell type. LNCaP showed an increase in late apoptosis at 0 h independent of PRF (p < 0.05), while PC-3 showed no significant difference at 0 h. The LDH assay showed an increase in LDH independent of PRF in LNCaP (p < 0.05 respectively), but no significant difference in PC-3. In vivo, tumor volume was compared and a significant reduction was observed at 10 Hz for LNCaP (p < 0.05) and 100 Hz for PC-3 (p < 0.001) at 3 weeks after the start of irradiation. The excised tumors were evaluated with Ki-67, Caspase-3, and CD-31 and showed a significant treatment effect independent of cell type and PRF (p < 0.001 respectively). Examining the mechanism behind the therapeutic effect of US irradiation revealed that the main effect was achieved by apoptosis induction rather than necrosis.

Ultrasound-assisted synthesis of copper-based catalysts for the electrocatalytic CO2 reduction: Effect of ultrasound irradiation, precursor concentration and calcination temperature

The reduction of high CO2 concentrations in the atmosphere is an imperative task to reduce the consequences of the greenhouse effect on our planet. Developing active and selective materials for electrochemical CO2 reduction towards value-added products is mandatory to bring this technology to a practical application. This work studied the effect of assisting Cu and Zn oxides co-precipitation with sonochemistry. Different factors were investigated: the ultrasounds (US) amplitude, the effect of US irradiation time during either precipitation or ageing processes, the precursor concentration and calcination temperature. The synthesised catalysts were tested for the electrocatalytic CO2 reduction reaction in a Rotating Disk Electrode (RDE) system. Faradaic efficiencies >14% towards alcohols were obtained using US-assisted synthesised Cu-based catalysts. Instead, with the US-prepared Cupper-Zinc-based catalysts, the selectivity towards H2 and C1 products (CO and formate) was improved, and the syngas productivity was increased by > ⁓1.4-fold compared to the non-sonicated one. The alcohols production of the best Cu-catalyst was also confirmed on scalable electrodes. Controlling the synthesis conditions allowed to tune the physicochemical properties of the nanoparticles, including specific surface area, porosity, crystallite size and phases. Mesoporous materials with a mean pores size of around 25 nm were found to induce a better CO2 diffusion and CO retention time in the porous network, improving the *CO intermediate adsorption at active sites, promoting its dimerisation and thus enhancing the selectivity towards C2+ alcohols. The here reported results open the way for new electrocatalysts designs with properly tuned porosity for the selective CO2 conversion to different valuable products.

Removal of drug dexamethasone from aqueous matrices using low frequency ultrasound: Kinetics, transformation products, and effect of microplastics

Sonochemical oxidation was employed for the degradation of the drug dexamethasone (Dex). The oxidation at 20 kHz followed pseudo-first-order kinetics and increased with applied ultrasound power density. Acoustic cavitation at 71 W/L was able to eliminate 500 μg/L of dexamethasone from ultrapure water at inherent pH in less than 60 min. The oxidation was enhanced at pH 3 and decreased at increased Dex concentration. Scavenging experiments with tert-butanol showed that hydroxyl radicals play a crucial role in decomposition, where the reaction mainly occurs on the gas-liquid interface of the formed cavities. The addition of chloride did not affect Dex removal, while in the presence of 10 mg/L of humic acid or bicarbonate, the apparent kinetic constant decreased from 0.0423 ± 0.004 min−1 to about 0.03 ± 0.002 min−1. The rate in secondary effluent was 3.3 times lower than in ultrapure water due to the complexity of the actual matrix. Six transformation products were identified via high resolution LC-MS during the sonochemical oxidation of 3 mg/L Dex in ultrapure water. The presence of polyethylene or polystyrene microplastics slightly enhanced DEX sonodegradation. The effect of ultrasound irradiation at 71 W/L for 60 min on the microplastics surfaces was inconsiderable.

Effect of Ultrasound Irradiation on the Properties and Sulfur Contents of Blended Very Low-Sulfur Fuel Oil (VLSFO)

Quality issues concerning very low-sulfur fuel oil (VLSFO) have increased significantly since the IMO sulfur-limit regulation became mandatory in 2020, as most VLSFO is produced by blending high-sulfur fuel oil (HSFO) with VLSFO. For instance, the conversion of VLSFO paraffins (C19 or higher alkanes) into waxes at low temperatures adversely affects cold flow properties. This study investigates the effects of ultrasonication on the chemical composition, dispersion stability, and sulfur content of samples prepared by blending ISO-F-DMA-grade marine gas oil (i.e., VLSFO) and ISO-F-RMG-grade marine heavy oil (i.e., HSFO) in volumetric ratios of 25:75 (BFO1), 50:50 (BFO2), and 75:25 (BFO3). The paraffin content decreased by 19.2% after 120 min of ultrasonic irradiation for BFO1 by 16.8% after 30 min for BFO3. The decrease in the content of high-molecular-weight compounds was faster at higher HSFO content; however, ultrasonication for longer-than-optimal times induced reaggregation, and thus, increased the content of high-molecular-weight compounds and decreased dispersion stability. In addition, ultrasonication did not significantly affect the sulfur content of BFO1 but decreased those of BFO2 (by 19% after 60 min) and BFO3 (by 25% after 30 min). Desulfurization efficiency increased with the increasing content of HSFO, as water present therein acted as an oxidant for oxidative desulfurization.

Ultrasound assisted synthesis of 5–7 membered heterocyclic rings in organic molecules

AbstractUltrasound synthesis is a powerful technique that is being used increasingly to accelerate organic reactions as a green synthetic approach. Ultrasonication has offered advantages over conventional methods in terms of enhanced yields, shorter reaction time, high selectivity and minimal side reaction. The current investigation is the review of papers published from 2016 to 2022 for the synthesis of organic heterocycles under the effect of ultrasound irradiation. It is a comprehensive compilation of sonochemical processes as a versatile technique to achieve synthesis of numerous organic scaffolds from simple carbocyclic compounds to complex and biologically active heterocyclic structural molecules. This review encompasses the examples of ultrasound supported synthetic reactions of multicomponent one pot processes as well as different steps flow synthesis. Ultrasound assisted synthesis have been proved as an eco‐friendly and benign approach for the synthesis of 5–7 membered heterocyclic rings, with one to three hetero atoms. Moreover Ultrasound synthesis has offered excellent yield in a vast majority of reactions under mild conditions without involving complicated purification procedures.

PD46-08 COMBINED TREATMENT WITH ULTRASOUND AND IMMUNE CHECKPOINT INHIBITORS FOR PROSTATE CANCER

You have accessJournal of UrologyCME1 May 2022PD46-08 COMBINED TREATMENT WITH ULTRASOUND AND IMMUNE CHECKPOINT INHIBITORS FOR PROSTATE CANCER Fuuka Hayashi, Katsumi Shigemura, Koichi Kitagawa, Noriaki Maeshige, Koki Maeda, and Masato Fujisawa Fuuka HayashiFuuka Hayashi More articles by this author , Katsumi ShigemuraKatsumi Shigemura More articles by this author , Koichi KitagawaKoichi Kitagawa More articles by this author , Noriaki MaeshigeNoriaki Maeshige More articles by this author , Koki MaedaKoki Maeda More articles by this author , and Masato FujisawaMasato Fujisawa More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002614.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Ultrasound (US) is mostly used for diagnostic purpose but could be used for cancer treatments if the US intensity or frequency fits to such purpose. Prostate cancer (PC) has the highest prevalence in the urological field, but indications of immune checkpoint inhibitors (ICI) for PC are limited to very few cases. Therefore, we verified the antitumor effect of US irradiation alone and the combined use of US and ICI in vitro and in vivo. METHODS: Human-derived PC cell line LNCaP and PC-3, and mouse-derived PC cell line TRAMP-C2 were used in experiments. US (3.0 W/cm2, 3 MHz, irradiation time rate: 20 %) was irradiated with repeated frequency of 1, 10, and 100 Hz. Cell proliferation was evaluated by MTS assay and apoptotic cells were analyzed by flow cytometry. We transplanted LNCaP, PC-3 cells into nude mice, and TRAMP-C2 cells into Balb/c nu/nu mice. US was irradiated on mice at 10 Hz and 100 Hz 3 times a week for 6 weeks. We also administered anti-PD-1 antibody to TRAMP-C2-bearing mice 5 times to verify the effect of combined use of US and ICI. After tumor collection, Immunohistochemical (IHC) stain with Ki-67, caspase-3, CD31 and CD3 were conducted. RESULTS: Cell proliferation assay showed US irradiation suppressed cell growth in LNCaP (at 10 Hz and 100 Hz, p<0.0001, respectively), PC-3 (at 1, 10, and 100 Hz, p=0.0002, p<0.0001, and p=0.0132), and TRAMP-C2 (at 1 Hz and 10 Hz, p<0.0001, respectively). In addition, US irradiation induced apoptosis in LNCaP (at 100 Hz, p=0.0368), PC-3 (at 1 Hz and 10 Hz, p=0.0447, p=0.0137), and TRAMP-C2 (at 1, 10, and 100 Hz, p=0.0129, p=0.0150, p=0.0017). In animal experiments, US irradiation at 100 Hz inhibited tumor growth in both LNCaP and PC-3-bearing mice (p=0.0419, p=0.0064). From IHC analysis, the expression level of Ki-67 was decreased at 100Hz in PC-3 (p=0.0467), and caspase-3 was decreased at 10 Hz and 100 Hz in both LNCaP (p=0.0007, p=0.0297) and PC-3 (p=0.0061, p=0.0115). In addition, the number of vessels was reduced at 10Hz and 100 Hz in both LNCaP (p=0.0290, p=0.0102) and PC3 (p=0.0026, p=0.0007). In TRAMP-C2 in vivo experiments, an antitumor effect was observed at 10 Hz, 100 Hz, and the combined use of ICI and 100 Hz of US (p=0.0365, p=0.0364, p=0.0393) compared to control. IHC stain revealed the number of CD3-positive cells increased at 100 Hz (p=0.0499). CONCLUSIONS: We found that US irradiation induces apoptosis and reduces cell growth. Moreover, tumor growth was suppressed by combined use of US and ICI. Further research on immune system activation will lead to a less invasive and more efficient treatment for PC. Source of Funding: none © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e791 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Fuuka Hayashi More articles by this author Katsumi Shigemura More articles by this author Koichi Kitagawa More articles by this author Noriaki Maeshige More articles by this author Koki Maeda More articles by this author Masato Fujisawa More articles by this author Expand All Advertisement PDF DownloadLoading ...

Combined Treatment with Ultrasound and Immune Checkpoint Inhibitors for Prostate Cancer.

Background: Ultrasound (US) is mostly used for diagnostic purpose but could be used for cancer treatments with a US intensity or frequency fitted to such a purpose. Prostate cancer (PC) has the highest prevalence in the urological field, but indications for immune checkpoint inhibitors (ICIs) for PC are limited to very few cases. In this study, we compared the antitumor effect of US irradiation alone with the combined use of US and ICIs in vitro and in vivo. Methods: PC cell line TRAMP-C2 cells were used in our experiments. TRAMP-C2 cells were irradiated with US with pulse repeated frequencies (PRF) of 1, 10, and 100 Hz. Cell proliferation was evaluated by MTS assay and apoptotic cells were analyzed using flow cytometry. To verify the antitumor effect of US irradiation on PC in vivo, we conducted animal experiments using mice. TRAMP-C2-bearing mice were irradiated with US with PRF of 10 and 100 Hz. Three weeks after the start of US irradiation, anti-PD-1 antibody was administered to the mice. Finally, mice were sacrificed and tumors were collected. Immunohistochemical (IHC) analyses were assessed for cleaved caspase-3 and CD3 in tumor cell extracts. Results: Cell proliferation assays showed that 1 and 10 Hz US significantly inhibited cell survival (p < 0.0001). In addition, US irradiation induced apoptosis at 1, 10, and 100 Hz (p = 0.0129, p = 0.0150, and p = 0.0017, respectively). In animal experiments, a significant tumor growth inhibitory effect was observed at 10 and 100 Hz, and 100 Hz + ICIs (p < 0.05, respectively). Hematoxylin–eosin (H–E) staining showed a significant increase in the necrotic area of the tumor at 100 Hz and 100 Hz + ICIs (p < 0.05, respectively). In addition, under IHC staining the expression level of cleaved caspase-3 and the number of CD3-positive cells increased at 100 Hz (p < 0.05, respectively). Conclusion: US irradiation induced apoptosis in cells and reduced cell viability. In vivo tumor growth was suppressed by combined treatment with US irradiation and ICIs. Further research on immune system activation will lead to less invasive and more efficient treatments for PC.

Effect of Ultrasound Irradiation during Cementation Process for Recovery of Iridium

Effect of Ultrasound Irradiation during Cementation Process for Recovery of Iridium

Effects of ultrasound irradiation on Au nanoparticles deposition on carbon-coated LiNi0.5Mn1.5O4 and its performance as a cathode material for Li ion batteries

LiNi0.5Mn1.5O4 (LMNO) has attracted considerable attention as a Li-ion battery cathode material, owing to its high discharge voltage of 4.7 V (vs. Li/Li+) and high energy density. However, the electronic conductivity of LMNO is low, resulting in a low discharge capacity at high current density. To overcome this limitation, we deposited Au nanoparticles (NPs), which have a high conductivity and chemical stability at high battery voltages, on carbon-coated LMNO (LMNO/C) using ultrasound irradiation. Consequently, Au NPs that are ∼16 nm in size were deposited on LMNO/C, and ultrasound irradiation was reported to disperse the NPs on LMNO/C more effectively than stirring. Furthermore, the deposition of Au NPs on LMNO/C using ultrasound irradiation improved its electronic conductivity, which is related to an increase in the discharge capacity due to the reduction of Ni4+ to Ni2+ in LMNO/C at a high current density.

Effect of ultrasound irradiation on asphaltene aggregation and implications to rheological behavior of bitumen

The present work investigates the contribution of asphaltene aggregation to bitumen viscosity subject to ultrasound irradiation. A West-African bitumen with a viscosity of 12043cP at room temperature was sonicated at low (38 kHz) and mild frequency (200 kHz) under controlled gas environment including air, nitrogen (N2) and carbon dioxide (CO2). The rheology of the bitumen, asphaltene content analyses as well as spectral studies were conducted. Herein was found that sonicating the bitumen at 200 kHz under air-environment reduces the initial viscosity up to 2079cP, which was twice larger than that obtained when a low frequency was used. In respect of the gas environment, it was shown that ultrasound irradiation under N2 environment could lower the bitumen viscosity up to 3274cP. A positive correlation between the asphaltene content and the viscosity reduction was established. The results from the spectral analyses including Fast Fourier Infrared and the observations from Scanned Electron Microscope were consistent with the rheological studies and led to the argument that the viscosity reduction results from either the scission of long chain molecules attached to the aromatic rings (when the applied frequency was altered under fixed gas environment) or the self-aggregation of asphaltene monomers (when gas environment was changed at fixed frequency).

Effect of ultrasound irradiation on some Biophysical Parameters of Human Blood (in vitro)

Ultrasound is commonly employed in clinical practice as a part of physical therapy. In this study, an attempt has been made to investigate the effect of ultrasound irradiation on some Biophysical Parameters (pH, Conductivity, and Refractive index) of human blood. Blood samples of volume 5 ml were collected from the donors each time an experiment was performed. Blood was then transferred to heparin anticoagulant tubes. The human blood samples were divided into two parts, that is, control sample and sample for irradiation. The human blood sample was irradiated using an ultrasonic interferometer of 3MHz frequency for a duration of 1 h in an identical and controlled environment. The biophysical parameter was determined and compared with that of the control sample. Variations were observed in the values of pH, conductivity, and refractive index of ultrasonically irradiated human blood sample compared with that of the control sample. This study gives us an idea regarding the effect of ultrasound on some of the most important biophysical parameters of human blood. Further, the results obtained in the present study can be utilized in the future for the work on the biological effects of ultrasound and interpret the in vivo effects.

The Abnormal Physicochemical Phenomena of Singlet Oxygen Sensor Green in Water in the Presence of Ultrasound

AbstractThe detection of Singlet oxygen (1O2) is of great interest to develop cancer therapies, because it can initiate a plethora of events that result in cell death. Singlet oxygen sensor green (SOSG) is considered the preferred probe because of its claimed high selectivity to Singlet oxygen (1O2). Although many researchers have used SOSG to detect 1O2 generation in Sonodynamic therapy (SDT) processes, the effect of ultrasound irradiation on SOSG has not been comprehensively evaluated. In this study, we conducted systematic experiments to determine SOSG activation in the presence of ultrasound irradiation. We found that the SOSG exhibited the abnormal physicochemical phenomena in distilled water in the presence of ultrasound. The fluorescence intensity of SOSG increased significantly when exposed to ultrasound alone. The results showed that there was a linear positive correlation between the treatment duration of different ultrasound intensities or SOSG concentrations and the fluorescence intensity of SOSG, respectively. In addition, scavenger tests also indicated that hydroxyl radicals (•OH) might be involved in the activation of SOSG. In conclusion, our results suggest that the influences of experimental conditions to SOSG must be fully considered, and that SOSG may not be a suitable probe for 1O2 in SDT.

Recovery of lactose from aqueous solution by application of ultrasound through millichannel

Abstract Instead of direct disposal of whey, extraction of valuable products from it may reduce the environmental pollution. In the present study, the effect of ultrasound irradiation through millichannel on recovery of lactose was investigated. The ultrasonic baths of varying amplitude (20–40%) and frequency (25–35 kHz), two different configurations of millichannel i.e., coil and serpentine, were used to know their individual and combined effect on the lactose yield. Box-Behnken design was employed to examine the interactive effect of different operating conditions. The recovery of lactose was enhanced approximately by 5–53% and induction time was reduced by 1.79–1.85 times in comparison to the conventional process. The size of the lactose crystals was reduced from 139.5 to 42.486 μm at 40% amplitude and 49.879 μm at 35 kHz frequency. Optimized condition showed 63% yield of lactose at 3.6 supersaturation, 35 kHz frequency, and 45 min of sonication time.

Influence of ultrasound irradiation on transient solidification characteristics in DC casting process: Numerical simulation and experimental verification

It is well known that solidification of molten metals occurs under the influence of transient unsteady phenomena, which are difficult to control in actual casting operation. Examples include buoyancy flows, natural heat convection, repeated remelting and solidification in mushy zone and solid shell at the mold interface. This paper presents the results suggesting that ultrasound waves, irradiated into the hot-top mold offers an attractive way to control the transient phenomena in DC casting of aluminum alloy billets. A novel mathematical model was developed to simulate the DC casting with considering transient melt flow, heat transfer, ultrasound propagation, acoustic streaming and solidification. It was found that ultrasound irradiation alters the solidification behavior of melt and sump evolution especially in the earlier stage of casting, however as the billet length increases, the sump profile becomes almost the same for both the ultrasonic and conventional castings. In this condition, the casting speed becomes the key parameter influencing the sump evolution and mushy zone volume. The results reveal that ultrasound-driven acoustic streaming and turbulent oscillations result in a suppression of buoyancy flow in the sump and lead to an increase of frequency of the melt temperature oscillations at the solidification interface. One of the useful results of these phenomena can be a more frequent repetition of remelting/solidification cycle and improvement of the billet quality, particularly the billet surface morphology. The effect of ultrasound irradiation on the billet morphology was verified experimentally using a pilot DC caster.

Effect of Ultrasound Irradiation on the Synthesis of Hydroxyapatite/Titanium Oxide Nanocomposites

Bioceramic materials, such as hydroxyapatite, Ca10(PO4)6(OH)2, (HAp), can be chemically bound to bone tissue; since they are bioactive and biocompatible. HAp, titanium oxide (TiO2), and hydroxyapatite/titanium oxide (HAp/TiO2) nanocomposite nanoparticles were obtained by ultrasound irradiation assisted by sol-gel and co-precipitation methods at different time intervals, using Ca(NO3)2•4H2O, (NH4)2HPO4, and TiOSO4•xH2O as calcium, phosphorus, and titanium sources, respectively. HAp, TiO2, and HAp/TiO2 nanocomposite powders were characterized by X-ray Diffraction (XRD) and Raman Spectroscopy. The percentages of anatase phase for TiO2 and of monoclinic and hexagonal phases for HAp were quantified by Rietveld refinement. Furthermore, sample crystallinity in each material was enhanced by increasing the ultrasound irradiation time. The nanoparticle shape was semi-spherical, agglomerated, and between 17 and 20 nm in size. The agglomeration of particles in the samples was corroborated with a Field Emission Scanning Electron Microscope (FESEM).

Catalytic-oxidative/adsorptive denitrogenation of model hydrocarbon fuels under ultrasonic field using magnetic reduced graphene oxide-based phosphomolybdic acid (PMo-Fe3O4/rGO).

In this work, the effect of ultrasound irradiation on the catalytic oxidative/adsorptive denitrogenation (COADN) of model hydrocarbon fuels (composed of pyrroleor indoleas an organonitrogen compounds dissolved in n-nonane) has been investigated using magnetic reduced graphene oxide supported with phosphomolybdic acid (PMo-Fe3O4/rGO) as a heterogeneous catalyst/adsorbent and hydrogen peroxide as an oxidant. The synthesized PMo-Fe3O4/rGO nanocomposite was characterized by XRD, FE-SEM, VSM and BET surface area analysis methods. Moreover, different experimental variables including catalyst dose, initial pyrrole/indoleconcentration, H2O2 to pyrrole/indole molar ratio, ultrasound power and sonication time have been studied on the COADN process. The regeneration/recyclability of PMo-Fe3O4/rGO catalyst was also examined. Experimental results revealed that, the ultrasound treatment significantly improved the adsorption process of organonitrogen compounds from model fuels (qe increased by 50.3% for pyrrole and 18% for indole). Furthermore, high ultrasound-aided catalytic oxidative denitrogenation efficiency (85.6% for pyrrole and 90% for indole) has been attained under optimal conditions (ultrasonic power=200W, sonication time=240min, catalyst dose=2g/L, and H2O2:pyrrole/indole molar ratio=5). The recyclability of catalyst displayed that the prepared catalyst can be reused five times without any significant reduction in its performance.