Ultrasonic-assisted Dispersion Research Articles

Deep Eutectic Solvents-Based Ultrasonic-Assisted Dispersive Liquid–Liquid Microextraction for the Determination of Organophosphorus Pesticides in Honeysuckle Dew Samples

A deep eutectic solvent (DES) with the ability to change from hydrophilic to hydrophobic was designed and synthesized and applied to the determination of organophosphorus (OPP) pesticides in honeysuckle dew samples. Choline chloride, phenol, and tetrahydrofuran (THF) were used as the hydrogen bond acceptor, hydrogen bond donor, and demulsifier, respectively. Eight OPP pesticides were extracted by DES coupled with ultrasonic-assisted extraction (UA) and then chromatographed by GC-MS. DES used as an extract solvent has the advantages of high extraction efficiency, low cost, and environmental protection. Furthermore, DES is compatible with GC-MS. The single factor experiment design and Box–Behnken design (BBD) were applied to the optimization of experimental factors, including the type and composition of extraction solvent, type of demulsifier solvent, the volume of DES and THF, pH of sample solution, and ultrasonic time. Under the optimum experimental conditions, the high degree of linearity from 0.1 to 20.0 ng mL−1 (R2 ≥ 0.9989), the limits of detection from 0.014 to 0.051 ng mL−1 (S/N = 3), and the recoveries of analytes from 81.4 to 104.4% with relative standard deviation below 8.6%. In addition, the adsorption mechanism of OPPs on DES was explored by adsorption kinetic studies. These results have demonstrated that the present method has offered an effective, accurate, and sensitive methodology for OPP pesticides in honeysuckle dew samples, and this method provides a reference for the detection of pesticide residues in traditional Chinese medicine.

Determination of Lorazepam and Diazepam Using Modified Nanocrystalline Cellulose for Ultrasonic-Assisted Dispersive Solid Phase Microextraction (UA-DSPME) and Gas Chromatography-Mass Spectrometry (GC-MS)

A rapid and effective method utilizing ultrasonic assisted-dispersive solid-phase microextraction coupled with gas chromatography/mass spectrometry (GC/MS) was developed for the determination of lorazepam and diazepam in biological and aqueous samples. A modified nanocrystalline cellulose-based sorbent was prepared and applied for the microextraction of the analytes. The extraction efficiency of the sorbents prepared using self-assembled N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, including cellulose nanostructure and modified nanocrystalline cellulose, was compared. The modified cellulose nanostructure was characterized using thermogravimetric analysis (TGA), energy dispersive X-ray (EDX), and Fourier transform infrared spectroscopy (FTIR). Additionally, the study investigated the effects of relevant factors on the extraction/desorption performance, including extraction time, ionic strength, and the type and volume of the desorption solvent. The method achieved limits of detection of 1 ng mL−1 and 3 ng mL−1 and quantification limits of 4 ng mL−1 and 10 ng mL−1 for lorazepam and diazepam, respectively. Furthermore, the developed method demonstrated good repeatability with relative standard deviations of 4% and 6% (n = 5) for the spiked analyte aqueous solutions at 50 ng mL−1. The method also exhibited high linearity (R > 0.9996) in the range from 10 to 1000 ng mL−1.

Electrochemical monitoring of congo red degradation using strontium titanate-doped biochar nanohybrids derived photocatalytic plates.

Present investigation demonstrates the development and characterization of strontium titanate (SrTiO3) doped biochar nanohybrid photocatalysts. Biochar nanohybrid was synthesized using an ultrasonic-assisted dispersion technique, which involved dispersing SrTiO3 nanoparticles into activated biochar at a weight ratio of 1:2 (w/w) under ambient conditions. The development of the biochar nanohybrid was verified through a comprehensive analysis of their spectral, microstructural, thermal, electrical, and electrochemical properties. The scanning electron microscopy analysis reveals a surface-associated multiphase morphology of the biochar nanohybrid, attributed to the uniform distribution of SrTiO3 within the activated biochar matrix. Biochar nanohybrid exhibited a reduced optical band gap of 2.77eV, accompanied by a crystallite size of 32.45. Thermogravimetric analysis revealed the thermal stability of the biochar nanohybrid, as evidenced by a char residue of 70.83% at 1000°C. The working electrodes derived from biochar nanohybrid have exhibited ohmic behavior and displayed a significantly enhanced DC conductivity (mS/cm) of 1.13, surpassing that of activated biochar (0.53) and SrTiO3 (0.62) at 100V. The developed biochar nanohybrid were employed for the degradation of congo red dye by exposing the dye solution to photocatalytic plates. These photocatalytic plates were prepared by coating biochar nanohybrid onto glass plates using epoxy-based reactive binders for secure binding. The photodegradation of congo red was evaluated through cyclic voltammetric analysis in a 0.1M KCl solution at pH 8.0, resulting in an impressive 99.95% photocatalytic efficiency in degrading a congo red solution (50mg/L). This study presents a novel approach for the fabrication of biochar nanohybrid-derived photocatalytic plates, offering high photocatalytic efficiency for the degradation of congo red dye.

Preparation of steel fiber-reinforced shells for investment casting using ultrasonic-assisted dispersion

In this work, steel fibers were added into a silica sol binder to prepare shells for investment casting. The green strength, high-temperature self-load deformation, heat transfer, and fiber dispersion in the shell were investigated. The effect of ultrasonic power on fiber dispersion in the shell and the silica sol was studied and discussed. The results suggest that, with a fiber addition amount of 0.15%, an ultrasonic power level of 1200 W can completely disperse the fibers in silica sol. It has been found that the reinforcement effect is the best when the fiber addition amount is 0.15%. When the ultrasonic power level was 1200 W, the strength reached the maximum value of 3.29 MPa, which was 0.74 MPa higher than that without ultrasonic agitation (2.55 MPa). Under ultrasonic agitation, the fibers were in monofilament state and well-bonded with the shell. Steel fibers have good thermal stability at high temperature and still exists in the shell; thus, they can support the shell and prevent its deformation. Under an ultrasonic power level of 1200 W and fiber addition amount of 0.15%, the high-temperature self-load deformation of the shell was 0.44%. It is concluded that, the more uniform the dispersion of the fibers, the better the heat dissipation performance of the shell.

Characterization and tribology performance of polyaniline-coated nanodiamond lubricant additives

Abstract The polyaniline (PANi)-coated nanodiamond (ND) composites were fabricated by the in situ polymerization process and dispersed in base oil as nanolubricant additives by ultrasonic-assisted dispersion. The morphology and microstructures of the nanocomposites were characterized. The in-house developed reciprocating tribo-device was utilized to conduct the tribological tests. An actual CrN piston ring–nitriding cylinder liner friction pair used in the diesel engine was employed to evaluate the effectiveness of the developed nanolubricant additives. The wear tests were conducted under conditions that were close to the actual work condition of the selected friction pair. Furthermore, the anti-scuffing performance was also investigated and the associated mechanisms were analyzed. The results show the polymerization process inhibited the agglomeration of the NDs that were well dispersed in the PANi matrix. The stable hydrogen bonding interactions and the surface confinement effect promote the dispersion of the nanocomposites in organic base oil effectively. The developed additive can improve the friction and wear performance of the ring–cylinder liner friction pair by 12–19 and 15–24%, respectively, compared with the base oil. With the increase of temperature, the effectiveness of the nanolubricant additives is enhanced. Under the oil-starved condition, the friction pairs lubricated with PANi/ND lubricants can sustain a longer stable period with a lower friction force, and the anti-scuffing time is almost three times longer. Concerning the overall tribological performance, the optimal content of the PANi/ND additive in base oil is 2 wt%.

Simultaneous Determination of Sulfonamides Antibiotics in Environmental Water and Seafood Samples Using Ultrasonic-Assisted Dispersive Liquid-Liquid Microextraction Coupled with High Performance Liquid Chromatography.

The residues and abuse of antibiotics have seriously endangered ecological balance and human health; meanwhile, antibiotics determination is very difficult because of their low levels and multiple categories in complicated matrices. Appropriate sample pretreatment is usually imperative to enrich (ultra)trace antibiotics and eliminate matrix interference prior to chromatographic analysis. Dispersive liquid-liquid microextraction (DLLME) has become an ideal pretreatment technique owing to its simplicity, effectiveness, low-consumption, etc. In this work, an ultrasonic-assisted DLLME (UA-DLLME) was developed for the simultaneous extraction of seven sulfonamides (SAs) antibiotics in environmental water and seafood samples coupled with HPLC-DAD determination. Several parameters affecting UA-DLLME efficiency were systematically optimized, and consequently the SAs were separated and detected within 14.5 min. The obtained limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.7–7.8 μg/L and 2.4–26.0 μg/L for three water samples (seawater, aquaculture wastewater and lake water) and two seafood samples (pomfrets and shrimps). High recoveries (80.0–116.0%) with low relative standard deviations (0.1–8.1%) were achieved for all the tested samples at three spiked levels. Notably, sulfadimethoxine was found at 24.49 μg/L in one seawater sample. The facile, robust and benign DLLME-HPLC method demonstrated promising perspectives for multiresidue analysis of antibiotics.

Determination of Metal Ions in Pinellia ternata by High Performance Liquid Chromatography-Ultraviolet Detector

In this study, trace amounts of heavy metal ions copper, lead, mercury and cobalt in Pinellia ternata samples were detected by ionic liquid ultrasonic assisted dispersion liquid–liquid microextraction, combined with high performance liquid chromatography-ultraviolet detector. The method used sodium diethyldithiocarbamate as complexing agent and phosphoric acid ionic liquid Trihexyl(tetradecyl) phosphine bis[(2,4,4-trimethyl)] amyl phosphonate (cyclophosphate IL104) as extractant. Methanol: 0.2% phosphoric acid (60:40) was used as mobile phase for separation and UV detector was used for detection, the flow rate was 1 mL/min and the injection volume was 10 μL. In this paper, the effects of sample pH, complexing agent concentration, ultrasonic time, centrifugation time and speed and ionic strength were optimized. Under the optimal conditions (50 μL ionic liquid cyclic phosphine IL104, pH = 5, 0.5% sodium diethyldithiocarbamate, ultrasonic time of 30 min, centrifugation speed of 4000 r/min, 0.1 g NaCl), the recovery of spiked standard was 89.0~98.2%. High performance liquid chromatography had the characteristics of low detection limit, accurate and reliable determination results, high sensitivity, strong specificity and good reproducibility.

Facile preparation of graphene film and sandwiched flexible poly(arylene ether nitrile)/graphene composite films with high EMI shielding efficiency

From the industrial grade graphene nanosheet (GNS) powder, the flexible, ultra-thin and freestanding graphene films are prepared using ultrasonic-assisted dispersion and suction filtration. The sandwiched composites films are prepared by layer-by-layer assembly using poly(arylene ether nitrile) (PEN) as polymer matrix. The strong Π···Π interaction pulls the graphene sheets together in a face-to-face way and they assembly into flexible graphene films. High electromagnetic interference shielding effectiveness (EMI SE) is shown due to multiple internal reflection and absorption inside the porous graphene films. A 3 μm thick graphene film shows EMI SE over 20 dB, specific SE (SE/density/thickness, SSE/t) of 72967 dB·cm2/g and absorption ratio over 92%. Moreover, the highest EMI SE of 77 dB is reached by sandwiching 3-layers of graphene films with PEN, and the composites films exhibit high flexibility, high tensile strength over 40 MPa and glass transition temperature of 185 °C.

Facile Use of Silver Nanoparticles-Loaded Alumina/Silica in Nanofluid Formulations for Enhanced Catalytic Performance toward 4-Nitrophenol Reduction.

The introduction of toxic chemicals into the environment can result in water pollution leading to the degradation of biodiversity as well as human health. This study presents a new approach of using metal oxides (Al2O3 and SiO2) modified with a plasmonic metal (silver, Ag) nanoparticles (NPs)-based nanofluid (NF) formulation for environmental remediation purposes. Firstly, we prepared the Al2O3 and SiO2 NFs of different concentrations (0.2 to 2.0 weight %) by ultrasonic-assisted dispersion of Al2O3 and SiO2 NPs with water as the base fluid. The thermo-physical (viscosity, activation energy, and thermal conductivity), electrical (AC conductivity and dielectric constant) and physical (ultrasonic velocity, density, refractive index) and stability characteristics were comparatively evaluated. The Al2O3 and SiO2 NPs were then catalytically activated by loading silver NPs to obtain Al2O3/SiO2@Ag composite NPs. The catalytic reduction of 4-nitrophenol (4-NP) with Al2O3/SiO2@Ag based NFs was followed. The catalytic efficiency of Al2O3@Ag NF and SiO2@Ag NF, for the 4-NP catalysis, is compared. Based on the catalytic rate constant evaluation, the catalytic reduction efficiency for 4-NP is found to be superior for 2% weight Al2O3@Ag NF (92.9 × 10−3 s−1) as compared to the SiO2@Ag NF (29.3 × 10−3 s−1). Importantly, the enhanced catalytic efficiency of 2% weight Al2O3@Ag NF for 4-NP removal is much higher than other metal NPs based catalysts reported in the literature, signifying the importance of NF formulation-based catalysis.

Ultrasonic-Assisted Dispersion of ZnO Nanoparticles to Sn-Bi Solder: A Study on Microstructure, Spreading, and Mechanical Properties

Nanocomposite Sn-Bi solders received noticeable attention for flexible electronics due to their improved mechanical properties. The main limitation is the dispersion of nanoparticles in the solder alloy. Accordingly, in this work, varying additions of ZnO nanoparticles were successfully dispersed into Sn57Bi solder via the liquid-state ultrasonic treatment. Nanocomposite solders were prepared using the melting and casting route. The solder alloys were then characterized for microstructure, spreading and mechanical properties. With increasing ZnO addition, the microstructure revealed significant refinement of Bi- and Sn-rich phases. Consequently, the eutectic lamellar spacing also decreases. The spreading improved up to 0.1 wt.% ZnO addition. For higher additions, nanocomposite solders experienced deterioration in spreading characteristics. The tensile strength of the solder increases with an increase in the amount of ZnO nanoparticles. High ductility is achieved for nanocomposite solder containing 0.05 wt.% ZnO. An attempt was made, to explain the effect of increasing ZnO nanoparticle addition on microstructural, spreading, and mechanical properties of Sn57Bi solder.

Synthesis of the Novel ZSM-5/NiO/MIL-101(Cr) Zeolite Catalyst Nanocomposite and Its Performance for the Sonodegradation of Organic Dyes in Aqueous Solutions

The current research emphasizes on the synthesis of the novel sonocatalyst nanocomposite of ZSM-5/NiO/MIL-101(Cr) zeolite by the simple ultrasonic-assisted dispersion method prior to its engagement in the degradation of the targeted organic dyes. The several techniques of FESEM, EDAX, X-ray dot-mapping, AFM, FTIR and XRD were alternatively designated to provide a comprehensive view of the fabricated catalyst specifications. Then, three considered organic dyes of methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) were all treated by the prepared ZSM-5/NiO/MIL-101(Cr) nanocomposite in the aqueous solutions accompanied via the ultrasound irradiation prior to the evaluation with the UV–Vis absorption analysis. Since it acts as an oxidizing agent, the use of H2O2 solution in the above sonodegradation reactions of dye contaminants was assumed indispensable. Moreover, the effect of several parameters like irradiation time, initial dye concentration, catalyst dose, and process type on the degradation of MB, RhB and MO were investigated. On the other hand, using the first-order model, the reaction kinetics of the understudy organic dye was accomplished as the values of 0.0870 min−1 and 7.9655 min were respectively gained for constant (kapp) and half-life (t1/2) in the MB degradation over the ZSM-5/NiO/MIL-101(Cr)/US/H2O2 system. Further, the collected results revealed the substantial function of •OH as a radical scavenger derived from H2O2 in sonocatalytic degradation process. Further, to provide a better understanding for the superiority of the new composite catalyst, the sonocatalytic capabilities of raw ZSM-5 and ZSM-5/NiO were investigated under the similar conditions and the results were reflected in this research.

Ultrasonic assisted-dispersive solid-phase extraction for rapid enrichment of N-nitrosodimethylamine in water

a novel and rapid analytical method was established for the extraction of N-nitrosodimethylamine in large-volume water samples. Pretreatment was on the basis of ultrasonic-assisted-dispersed solid phase extraction. Coco housing activated carbon was incorporated into the water samples, and the rapid enrichment of N-nitrosodimethylamine was realized by implementing ultrasonic-assisted dispersion. After that, the suspension was filtered by suction, and the residue was eluted by dichloromethane. The eluate was collected and then concentrated to dry using rotary evaporation. Ultra-high performance liquid chromatography tandem mass spectrometer, which equipped with atmospheric pressure chemical ionization source was employed for determination under the multiple reaction monitoring mode. Limit of detection and quantification for N-nitrosodimethylamine in 500 mL water was 2. 0 ng/mL and 6. 0 ng/mL, respectively. Throughout the validation, good linearity with R~2>0. 999 were achieved with the range from 0. 5 ng/mL to 150. 0 ng/mL. Satisfactory recovery(95. 7%-100. 8%) and inter-day reproducibility(<4. 2%) were obtained by three-level spiking experiments in different water matrices. Finally, the established method was applied for analysis of 48 real samples, the detectable concentrations of positive samples were in the range of <2. 0 ng/L to 14. 4 ng/L. Compared with the traditional solid-phase extraction method, this method ology showed the characteristics of rapid and more efficient, and could save at least 50% of the pretreatment time. Meanwhile, the result of method ology validation were satisfactory.

MoS2/MWCNTs porous nanohybrid network with oxidase-like characteristic as electrochemical nanozyme sensor coupled with machine learning for intelligent analysis of carbendazim

Electrochemical nanozyme sensor coupled with machine learning (ML) for intelligent analysis of carbendazim (CBZ) residues in tea and rice samples using graphene-like molybdenum disulfide (MoS2)/multi-walled carbon nanotubes (MWCNTs) porous nanohybrid network with oxidase-like characteristic was developed. MoS2/MWCNTs porous nanohybrid network was prepared by ultrasonic dispersion of MWCNTs into MoS2 aqueous dispersion that was obtained by ultrasonic-assisted dispersion in sodium carboxymethyl cellulose water solution, which displayed low electron transfer resistance, high effective surface area, excellent film electrode stability. Machine learning via the artificial neural network for the intelligent analysis of CBZ was discussed in comparison with traditional regression analysis. Good electrocatalytic capacity, unique oxidase-like characteristic, wide linear range with 0.04–100 μM, low limit of detection with 7.4 nM, high sensitivity, and satisfactory practicability for CBZ demonstrated that electrochemical nanozyme sensor for the intelligent analysis of CBZ residues in edible agro-products was feasible. This will provide a new electrochemical sensing platform for the development of a graphene-like nanozyme sensor and its intelligent analysis of CBZ in food and agro-product safety.

Ultrasonic-Assisted Dispersion of ZnO Nanoparticles and Its Inhibition Activity to Trichoderma viride.

The activity inhibition of fungi by ZnO nanoparticles (NPs) has shown huge potential applications in the area of hygienic coatings. However, the inhibition efficiency was limited due to the agglomeration of NPs. To obtain well-dispersed and highly stabilized ZnO nanofluids, ZnO NPs were capped with four kinds of surfactants under ultrasonication. The capping procedure was optimized by varying the dosage of surfactants, the ultrasonic duration, ultrasonic power and temperature. Capped ZnO nanofluids were then used for the inhibition of Trichoderma viride. The influence on the activity of the capping conditions, illumination, ZnO NPs content, humidity and temperature were investigated in details. Results suggest that well-dispersed ZnO NPs were obtained through ultrasonic-assisted functionalization using sodium polyacrylate as a dispersant. Moreover, capped ZnO nanofluids revealed long-term stability at pH above 6. The optimal capping procedure was obtained for a sonication power of 250 W, treatment duration of 40 min, dosage of 0.4% and temperature of 60 °C. Antifungal tests indicated that capped ZnO NPs showed an inhibition ability versus T. viride even in the dark. The antifungal ability of ZnO NPs increased with the increasing ZnO content, and humidity and temperature only affected the growth of fungi. Capped ZnO NPs showed an excellent antifungal performance even in the circumstance that was beneficial for the fungi growth (temperature of 30 °C, humidity of 95%), demonstrating the antimicrobial capability in practical applications.

Supramolecular-Based Ultrasonic-Assisted Dispersion Solidification Liquid-Liquid Microextraction of Copper and Cobalt Prior to Their Flame Atomic Absorption Spectrometry Determination.

In the present work, a simple, efficient, and environmentally friendly method was proposed for the simultaneous preconcentration and determination of minute quantities of copper and cobalt in water samples and serum by a supramolecular-based ultrasonic-assisted dispersion solidification liquid-liquid microextraction (DSLLME) procedure coupled with flame atomic absorption spectrometry. The procedure is based on the DSLLME of copper and cobalt with decanoic acid-tetrahydrofuran supramolecular solvent (SUPRAS) in the presence of sodium diethyldithiocarbamate, as the complexing agent. SUPRAS is a nanostructured liquid generated from amphiphiles through a sequential self-assembly process occurring on two scales, molecular and nano. Several variables that affect the extraction efficiency-including pH, concentration of complexing agent, volume of the extraction and dispersive solvents (volume of SUPRAS), sonication time, and ionic strength-were investigated and optimized. The method provided enrichment factors of 23.31 and 22.38 for copper and cobalt, respectively. The preconcentration factor for the two analytes was 20.00. Calibration plots were linear in the range of 5.00-700.00 ng/mL for copper and 5.00-500.00 ng/mL for cobalt, with correlations of determination of 0.9973 and 0.9981. The precision of the method were expressed as RSDs for six replicate measurements and LODs and found to be ±4.10 and ±2.30% for copper and 2.90 and 3.50 ng/mL for cobalt. The proposed method was successfully applied to the simultaneous determination of trace copper and cobalt in real water samples and serum with satisfactory results.

Preparation and characterization of polycarbonate/multiwalled carbon nanotube nanocomposites.

A polymer nanocomposite was produced by ultrasonic-assisted dispersion of multiwalled carbon nanotubes (MWCNTs) in a polycarbonate matrix using p-xylene and dichloromethane as the solvents. The filler loading was varied from 1 to 3 wt % in order to examine the effect of MWCNTs on the structure and properties of the composites. The nanocomposites were characterized by DSC, DTA, TGA, UV–vis, FTIR and Raman spectroscopy to evaluate the changes induced by the filler in the polymer matrix. UV–vis, FTIR and Raman spectroscopy measurements confirmed the presence of the dispersed phase in the composite films, while TGA and DSC analysis of the nanocomposites revealed enhanced thermal stability and decreased crystallinity, respectively, as compared to the neat polymer. The proposed composites can find application in a number of everyday products where polycarbonate is the base polymer.

Investigations into lubrication in grinding processes using MWCNTs nanofluids with ultrasonic-assisted dispersion

To improve the quality of grinding processes, nanofluids can replace traditional cutting fluids, improving cooling, lubrication, and surface finish. However, a disadvantage of nanofluids is that a suspension of nanoparticles tends to agglomerate in the course of a long machining process, leading to cooling performance degradation. Although adding surfactants can improve nanoparticle dispersion, this may pollute the nanoparticles. The present research aims to solve these problems using ultrasonic assistance, first taking advantage of the excellent thermal conductivity of multi-walled carbon nanotubes in nanofluids, with vegetable oil as a cutting fluid, and second, devising an effective ultrasonic-assisted oscillator set-up for Minimum Quantity Lubrication. The oscillator agitates the nanofluid through ultrasonic cavitation to keep the nanoparticles dispersed. This experiment uses NAK80 mold steel as a material for grinding, with four different lubrication methods: dry, MQL, nanofluid (0.25 wt%)/MQL, and nanofluid (0.25 wt%)/ultrasonic MQL. The grinding performance and effects of ultrasonic-assisted dispersion are discussed. The results show that nanofluid/ultrasonic MQL grinding can effectively reduce the agglomeration of nanoparticles, and reduce grinding forces, grinding temperature, and surface roughness to a greater degree than other lubrication methods.

Dielectric studies of al nanoparticle reinforced epoxy resin composites

Epoxy (EP) resin based nanocomposites with aluminum (Al) nanoparticles were prepared by solution method, with ultrasonic assisted dispersion followed by hot‐pressing methods. The dielectric permittivity, loss tangent, conductivity, and electric modulus of the nanocomposites were investigated by dielectric spectroscopy measurements in a wide frequency range from 1 to 107 Hz at temperatures from −20°C to 200°C. For all samples, the dielectric permittivity, dissipation factor, and electric conductivity increase with increasing temperature due to enhanced chain mobility above glass transition temperature (Tg). Broadband dielectric spectroscopy shows the multiple dielectric processes in the Al/epoxy nanocomposites corresponding to interfacial polarization (IP), α‐relaxation, and ionic conductivity, respectively. IP is detected at low frequencies and high temperatures. A primary α‐relaxation process is found at near Tg at the middle frequencies and the intermediate dipolar effect (IDE) is presented at high frequencies. The mechanisms responsible for dielectric relaxation, conductivity process, and electric modulus response have been discussed in detail. POLYM. COMPOS., 39:887–894, 2018. © 2016 Society of Plastics Engineers

Application of an ionic-liquid combined with ultrasonic-assisted dispersion ofgold nanoparticles for micro-solid phase extraction of unmetabolized pyridoxine and folic acid in biological fluids prior to high-performance liquid chromatography

A facile and efficient protocol was suggested for the synthesis of gold nanoparticles (Au NPs) and their subsequent transfer to aqueous solution using 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, following vigorous shaking with ultrasonic waves.

Carbon nitride nanosheets decorated with WO3 nanorods: Ultrasonic-assisted facile synthesis and catalytic application in the green manufacture of dialdehydes

Carbon nitride nanosheets decorated with WO3 nanorods (WO3/g-C3N4) were fabricated via ultrasonic-assisted dispersion and conventional incipient wetness impregnation method. It is found that ultrasonic promoted the formation of g-C3N4 nanosheets efficiently. The promotion effect in the structural evolution and catalytic performance for the rod-like structure of WO3 caused by g-C3N4 nanosheets were well studied. For the first time, the novel WO3/g-C3N4 nanocomposites were used as efficient catalysts in the green process of dialdehydes from the selective oxidation of cycloalkene oxides using H2O2 as a clean oxidant, owing to the high dispersion of active sites and the strong interaction between cycloalkene oxides and the NH or NH2 groups on the surface of g-C3N4 sheets. Here, C3N4 nanosheets are considered as the catalyst support and co-catalyst as well. The novel nanocomposites are very stable and can be reused for five times without obvious loss of catalytic activity.