•Effect of ultrasound parameters on bulk and surface nanobubbles are reviewed.•Generation and stability mechanisms of nanobubbles in acoustic fields are discussed.•Future research focuses in the ...effect of ultrasound on nanobubbles are given.
The generation, and stability of nanobubbles are of particular interest for fundamental research and have potential application in numerous fields. Several attempts were made in the literature to produce nanobubbles through acoustic cavitation. However, the generation and stability mechanisms of nanobubbles in the acoustic field are unclear. Here, we review the effect of ultrasound parameters on bulk nanobubbles and surface nanobubbles. On this basis, we discuss the proposed generation and stability mechanisms of nanobubbles from the perspective of transient and stable acoustic cavitation. Moreover, we propose some future research directions for a deeper understanding of the role of ultrasound in the generation and stability of nanobubbles.
In recent years, the synthesis of Au–Ag bimetallic nanoparticles has garnered immense attention due to their potential applications in diverse fields, particularly in the realm of medicine and ...healthcare. The development of efficient synthesis methods is crucial in harnessing their unique properties for medical applications. Among the synthesis methods, pulsed laser ablation in a liquid environment has emerged as a robust and versatile method for precisely tailoring the synthesis of bimetallic nanoparticles. This manuscript provides an overview of the fundamentals of the pulsed laser ablation in a liquid method, elucidating the critical factors involved. It comprehensively explores the pivotal factors influencing Au–Ag bimetallic nanoparticle synthesis, delving into the material composition, laser parameters, and environmental conditions. Furthermore, this review highlights the promising strides made in antibacterial, photothermal, and diagnostic applications. Despite the remarkable progress, the manuscript also outlines the existing limitations and challenges in this advanced synthesis technique. By providing a thorough examination of the current state of research, this review aims to pave the way for future innovations in the field, driving the development of novel, safe, and effective medical technologies based on Au–Ag bimetallic nanoparticles.
•Ultrasonic parameters of graphite flotation were optimized by Box–Behnken design.•Horn-type ultrasound produced a better flotation efficiency than that of bath-type.•Dual-frequency ultrasound was ...first employed for graphite flotation.•Related mechanisms are cavitation intensity and formed bubble-particle aggregates.
Ultrasound has emerged as a promising technique for improving the mineral flotation performance. However, limited research exists regarding the influence of different ultrasound types on the flotation process. Specifically, the impact of combined ultrasound and the comparison of horn- and bath-type ultrasounds on flotation have not been fully investigated. To address this knowledge gap, a comprehensive study to explore the effects of different ultrasonic pretreatments on the flotation of flake graphite was conducted. A Box-Behnken design is employed to analyze the effects of combined ultrasound on graphite flotation. By characterizing the properties of graphite samples before and after the ultrasonic treatment, the aim is to elucidate the mechanism underlying the impact of ultrasound on graphite flotation. The experimental results indicated that the ultrasonic cavitation intensity exerted a significant influence on the graphite flotation recovery. Both horn- and bath- type ultrasounds contributed to flotation, but horn-type ultrasound demonstrated a more pronounced effect, leading to a 7% increase in flotation recovery, whereas bath-type ultrasound resulted in only a 2% increase. Furthermore, the cavitation intensity of combined ultrasound was found to be higher than that of single-frequency ultrasound in the same duration. However, the performance of graphite flotation was better with short duration combined ultrasound pretreatment, while the opposite trend was observed for a long duration ultrasound pretreatment. These findings may inform the development of more efficient and effective ultrasonic pretreatments for flotation separation processes.
Pulsed laser ablation in liquid (PLAL) has verified its surpassing advantages in the fabrication of several high purity nanostructured metals and metal oxides. In this work, ZnO/CuO heterostructure ...nanocomposites have been fabricated by laser ablation a Q switched Nd: YAG laser beam (1064 nm, 10 Hz, pulse energy and pulse with 30 mJand 10 ns) is focused on the surface of theZnOthin film for 10 min. The fabricated ZnO/CuO nanocomposite was then characterized using transmission electron microscopy (TEM), UV–vis spectrophotometer, X-ray diffraction (XRD), and Raman spectroscopy to investigate the structural, compositional, and optical properties of the fabricated nanocomposite. The synthesized nanocomposites were evaluated as antibacterial agents against both the gram-positive bacterium S. aureus subsp. aureus ATCCBAA-977, and the gram-negative bacteria E. coli ATCC8739, K. pneumoniae subsp. pneumoniaeATCC700603, and P. aeruginosa ATCC27853. The as-fabricated ZnO/CuO nanocomposite demonstrated outstanding antibacterial activity except in the case of K. pneumoniae subsp. pneumoniae ATCC700603 while the maximum activity was observed against E. coli ATCC8739.
The collidal bimentalic nanoparticles of ZnO-Ag were prepared by laser ablation technqiue. The sysenthized bimetalic nanoparticles were characterized by UV–Vis spectrophotometry, Scanning Electron ...Microscopy (SEM), Energy Dispersive X-ray spectrometry (EDX), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Photo-Luminescence (PL). These techniques confirmed the formation of the bimetalic nanocompiste and showed that the size distribution of the synthesized bimetallic nanoparticles varied from 30 to 130 nm. The anticancer activity was validated by measuring the cell cytotocicty by MTT (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide) test applying HCT-116 and HELA cancer cell line. The cell lines’ sensitivity was the highest at 10 µg/mL of ZnO-Ag composite. This indicates that the bimetallic composite ZnO-Ag prepared by laser ablation technique is suitable for cancer treatment.
This study reports the synthesis of Au-decorated MCM-41 mesoporous nanoparticles using a laser-ablation technique. It was observed that the number of Au attached to MCM-41 nanostructures was ...dependent on the amount of encapsulated Cationic surfactant (cetyl ammonium bromide (CTAB) volume. The chemical group of the prepared nanoparticles was analyzed by FT-IR spectroscopy, where different absorption peaks corresponding to Au and MCM-41 were observed. The observed band region was ∼1090, 966, 801, 2918, and 1847 cm−1 for different samples, clearly confirming the successful preparation of MCM-41 with CTAB and Au-decorated MCM-41 nanoparticles using environmentally friendly laser-ablation approach. The surface morphology of the prepared nanoparticles were performed using TEM techniques. The TEM analysis of the MCM-41 specimen showed silica spheres with an average size of around 200 nm. Furthermore, Raman spectroscopy was done to evaluate the chemical structure of the prepared nanoparticles. It was seen that the prepared Au NPs decorated the MCM-41 system facilitated strong Raman peaks of CTAB. In addition, eight distinct Raman peaks were observed in the presence of Au NPs. This new functionalized method using the laser-ablation approach for mesoporous nanoparticles will participate effectively in multiple applications, especially the encapsulated molecule sensing and detection.
Developing a nanosized platform for annihilating cancer cells is highly promising and desirable in the field of nanomedicine especially when an eco-friendly synthesis protocol such as laser ablation ...is employed. Herein, pulsed laser ablation technique was used to fabricate Au/ZnO nanocomposite in deionized water. The prepared nanostructures were examined using HRTEM, SEM, EDX, XRD, UV–Vis, and Raman spectroscopy. An in vitro cytotoxicity evaluation of the prepared Au/ZnO nanocomposite on human colorectal carcinoma HCT116 and cervical cancer HeLa cells reveals the strong inhibitory action of the nanomaterials on the cancer cells. The influence of the nanocomposites on healthy HEK-293 cell line used as a control was minimal. The outcomes of this work mark the merits of laser ablation in the fabrication of highly pure nanomaterials with good efficacy against cancer cells.
Wettability has been the focal point of many studies in metal oxide materials due to their applications in water–gas shift reactions, organic reactions, thermochemical water splitting, and ...photocatalysis. This paper presents the results of systematic experimental studies on the wettability of surfaces of nanostructured transition-metal oxides (TMOs) (Al2O3, CeO2, and AlCeO3). The wettability of nanoparticles was investigated by measuring contact angles of different concentrations of water-based nanofluids (0.05–0.1 wt%) on the glass slide. The morphology, the heterostructure, and the nature of incorporated nanoparticles were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Characteristic diffraction patterns of the nanomaterials were evaluated using energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The contact angles of water–Al2O3, water–CeO2, and water–AlCeO3 were measured as 77.5 ± 5°, 89.8 ± 4°, and 69.2 ± 1°, respectively. This study suggests that AlCeO3 is strongly water-wet (hydrophilic), while CeO2 is weakly water-wet (hydrophobic). It further demonstrated that the sizes and compositions of the nanoparticles are key parameters that influence their wetting behaviors.
Bubble-particle attachment is a key factor in various material processing such as wastewater treatment and flotation separation. Nanobubble's formation and its stability on hydrophobic surfaces with ...and without surfactants have been scientifically proven and extensively studied in various investigations. However, the influence of particle roughness on the hydrophilic particle-air bubble attachment, which could be completely different from hydrophobic particle-bubble attachment in the presence of nanobubbles, has not been addressed. For tackling this gap, the present work investigated the impact of nanobubbles on the roughed surfaces of glass bead particles. The temperature rise technique as a known method was used for micro/nanobubble size generation. The glass beads were modified by the commonly applied abrasion method to create different roughness magnitudes. The particle-bubble assessment results indicated that the particle roughness could potentially affect the bubble attachment of hydrophilic glass beads while the attachment area of smooth particles was almost zero. Outcomes also were revealed that the modified attachment rate constant increased from 0.1180 to 2.2802 s−1 with the increase of particle surface roughness, indicating a shortening of attachment performance by enhancing the particle surface roughness. However, it was observed that the temperature rise method could improve the particle-bubble attachment only to a marginal extent.
Recently, titanium dioxide (TiO2) nanomaterials have gained increased attention because of their cost-effective, safe, stable, non-toxic, non-carcinogenic, photocatalytic, bactericidal, biomedical, ...industrial and waste-water treatment applications. The aim of the present work is the synthesis of electrospun TiO2 nanofibers (NFs) in the presence of different amounts of air–argon mixtures using sol-gel and electrospinning approaches. The physicochemical properties of the synthesized NFs were examined by scanning and transmission electron microscopies (SEM and TEM) coupled with energy-dispersive X-ray spectroscopy (EDX), ultraviolet-visible spectroscopy and thermogravimetric analyzer (TGA). The antibacterial and antibiofilm activity of synthesized NFs against Gram-negative Pseudomonas aeruginosa and Gram-positive methicillin-resistant Staphylococcusaureus (MRSA) was investigated by determining their minimum bacteriostatic and bactericidal values. The topological and morphological alteration caused by TiO2 NFs in bacterial cells was further analyzed by SEM. TiO2 NFs that were calcined in a 25% air-75% argon mixture showed maximum antibacterial and antibiofilm activities. The minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) value of TiO2 NFs against P. aeruginosa was 3 and 6 mg/mL and that for MRSA was 6 and 12 mg/mL, respectively. The MIC/MBC and SEM results show that TiO2 NFs were more active against Gram-negative P. aeruginosa cells than Gram-positive S. aureus. The inhibition of biofilm formation by TiO2 NFs was investigated quantitatively by tissue culture plate method using crystal violet assay and it was found that TiO2 NFs inhibited biofilm formation by MRSA and P. aeruginosa in a dose-dependent manner. TiO2 NFs calcined in a 25% air-75% argon mixture exhibited maximum biofilm formation inhibition of 75.2% for MRSA and 72.3% for P. aeruginosa at 2 mg/mL, respectively. The antibacterial and antibiofilm results suggest that TiO2 NFs can be used to coat various inanimate objects, in food packaging and in waste-water treatment and purification to prevent bacterial growth and biofilm formation.
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