Current Nanomaterials - Volume 8, Issue 4, 2023

Nanofluids are a new class of nanomaterials suspended in a base liquid. Nanofluids have shown extremely distinctive properties that give tremendous opportunities for a wide range of applications. Nanofluids are a novel group of heat transfer fluids that have attracted the attention of researchers from various fields due to their intensive thermal properties. This systematic review highlights the synthesis, stability, physical treatment, and applications of nanofluids in various sectors. Nanofluids are used in different sectors as the coolant in machinery, cooling of electronics, in chillers, cooling of diesel electronics generators, in a boiler cool gas reductions, and the manufacturing industry. The manufacturing process is one of the most fundamental and well-proven industrial processes in product- based industries. Cutting fluids play a critical function in lowering manufacturing cycle time as well as cutting costs during the machining process. A review of the importance of the machining process, as well as the use of nanofluids as cutting fluids, has been investigated in this work. To achieve these goals, cutting force, surface quality, tool and workpiece interface temperature, tool geometry, and the impacts of environmental situations were studied. Various vital specifications, such as the type of nanoparticle, a cutting tool used, work material type, and machining processes like turning, milling, drilling, and grinding were studied and thoroughly summarised in this work. If the machining parameters were used correctly, a greater heat transfer rate would be observed due to changes in lubricating characteristics and physical parameters.

Nanotechnology is a promising science with new aspects to fight and prevent various diseases using nanomaterials. The capability to expose the structure and functions of biosystems at the nanoscale level supports research leading to development in biology, biotechnology, medicine and healthcare. This is predominantly advantageous in treating microbial infections as an alternative to antibiotics. However, widespread production, and use and misuse of antibiotics have led to the emergence of Multiple-Drug Resistant (MDR) pathogenic bacteria. Due to infectious diseases from these drug-resistant pathogenic strains, human mortality rates have consistently increased and are becoming an epidemic in our society. Consequently, there is a strong demand for developing novel strategies and new materials that can cope with these problems. The emergence of nanotechnology has created many new antimicrobial options. The small size of these nanomaterials is suitable for carrying out biological operations. Several metals and metal oxides, such as silver, copper, gold, zinc oxide and iron oxide nanoparticle types, have shown toxicity toward several pathogenic microbes. Metal-based nanoparticles have been broadly examined for a set of biomedical applications. According to the World Health Organization, the reduced size and selectivity of metal-based nanoparticles for bacteria have established them to be effective against pathogens, causing concern. Metal-based nanoparticles are known to have non-specific bacterial toxicity mechanisms, which not only make the development of resistance by bacteria difficult, but also widen the spectrum of antibacterial activity. Metal-based nanoparticle efficiency studies achieved so far have revealed promising results against both Gram-positive and Gram-negative bacteria. Here we discuss the potential nanomaterials to either treat microbial resistance or induce the development of resistance. However, fundamental research is required to focus on the molecular mechanism causing the antimicrobial activity of nanomaterials.

Carbon Nanotubes (CNTs) are a relatively new class of technical materials with a variety of unique and beneficial features. CNT is a revolutionary carrier technology for both tiny and big medicinal compounds. These formulations can be surface engineered and functionalized with predefined functional groups to control their physical and biological characteristics. CNTs have proven potential for cancer therapy along with other target-oriented therapy due to their unique features, such as ease of cell viability, high drug stacking, thermal ablation, and exceptional intrinsic physical and chemical characteristics. Graphite with Sp2 bonded carbon atoms is used for the synthesis of CNT. CNTs are fabricated in a variety of ways, including arc discharge, laser ablation, chemical vapor deposition, flame synthesis, and silane solution. The present review summarises methods of preparation, types, and various applications of CNT.

Nanotechnology has enabled sensors to detect and sense a very small amount of chemical vapors. Sensors play a major role in our daily life. The use of sensors has made human life easy. One such type of sensor is the Gas sensor made up of Semiconducting metal oxides. These sensors have their own unique features which help in the easy monitoring of toxic gases. Out of all the metal oxide present, the gas sensors made up of ZnO nanostructures are mostly used in the gas sensing industry. ZnO has become a research hotspot of gas-sensing material because of the variation in resistance observed on the surface. These resistance changes are observed due to the adsorption and desorption of gases. In this review, we will be discussing the ZnO nanostructures, their preparation and their applications in the sensing of various toxic and flammable gases.

The eye is a complex organ in the body containing a repertoire of metabolite indicators such as glucose, peptides, specialized ions, and many critical biological data such as Intraocular Pressure (IOP), corneal temperature, and pH. Contact lens research and patient care have progressed substantially throughout the last three decades; hence smart contact lenses were developed with significant advancements in material biocompatibility, better lens layouts, the healthcare system, and more flexible and efficient modalities. Smart contact lenses are adjustable sophisticated visual prosthesis devices that monitor various significant physical and biochemical changes in ocular disorders, which are noninvasive and continuous. Wearable systems that utilize bodily fluids like sweat tears, saliva, and electrochemical interactions with steady physiological state and illness monitoring are currently developing. Because of its ease of access, fabrication, and noninvasiveness, tear fluid is commonly used to assess ocular disorders, blood glucose, and even cancers. Furthermore, the integration of nanotechnology into contact lenses has emerged as a promising platform for noninvasive point-of-care diagnostics. Utilizing nano-based contact lenses for ocular drug delivery is a new study area in bioengineering and innovative medical techniques. Despite all of the research done in this area, new technologies are still in their early stages of development, and more work in terms of clinical trials is required to commercialize nanotechnology-based contact lenses. This article encompasses nanotechnologybased smart contact lens technology, including materials, advancements, applications, sensor technologies, and prospects.

Background: More than 260 million people worldwide are affected by excess fluoride (F- > 1.5 mg/L) in their drinking water. Fluorosis of the teeth and skeleton, among other health issues, is caused by it. Objective: The aim of this study is to evaluate the fluoride removal from contaminated water using graphene-based new adsorbent material. Methods: Graphene (G) was prepared by a facile liquid-phase exfoliation method. CeO2 nanoparticles (NPs) were synthesized by the co-precipitation method. G was treated with CeO2 NPs in a probe sonicator to generate G/Ce material in solution. Finally, the impregnation evaporation process synthesized the G/Ce supported on activated carbon composite (G/Ce/AC). Results: FE-SEM analysis shows that the crumpling and scrolling sheets of G, the nanosized spherical shape of CeO2 NPs and a thick layer of nano-sized spherical particles has built up on the surface of graphene in G/Ce/AC composite. After conversion to G/Ce/AC Composite, the specific surface area of graphene was increased from 3.08 to 485.3621 m²/g. The adsorption of fluoride on G/Ce/AC was investigated using batch systems (effects of pH, contact time, adsorbent dosage and the initial fluoride concentration), adsorption isotherm and kinetic studies. The pseudo-second order was the one that best described the kinetic data, while the Langmuir isotherm best described the equilibrium data with a maximum adsorption capacity equal to 27.9 mg/g. Conclusion: Therefore, the results show that the G/Ce/AC composite was well synthesized and has excellent fluoride adsorption capacity compared to other materials already evaluated for this purpose.

Background: 2D nanostructures are greatly interested in different technological applications, particularly optoelectronics. Tin oxide 2D nanostructures have shown great transparency and ideal charge carrier transport properties. Objective: The current study aims to evaluate the main characteristics of 2D-nanostructures observed during the synthesis of hydrated forms of tin oxide (II) or (IV) doped with Mn. Methods: A chemical co-precipitation method was used for the synthesis of the hydrated forms of tin oxide (II) or (IV) with different conditions on time (1 and 1.5 h) and temperature (60ºC and 90ºC), using MnCl2 as the manganese source. Results: X-ray diffraction and XPS results revealed the formation of the hydroromarchite phase (Sn6O4(OH)4) as the main product of the synthesis reaction. Scanning electron microscopy images were used to identify and measure, in a first approach, the 2D nanostructures observed as a result of the synthesis. Morphological characterization using different transmission electron microscopy techniques revealed the presence of nanoparticles that were observed to self-assemble to form the 2D nanostructures observed (nanorods and nanosheets). Nonetheless, selected-area electron diffraction suggested the presence of the cassiterite phase (SnO2) in the nanoparticles forming the 2D nanostructures. Furthermore, chemical analyses using energy-dispersive X-ray spectroscopy supported the observations made by the diffraction studies regarding the presence of cassiterite phase (SnO2) in the 2D nanostructures. The number of 2D nanostructures observed in the analyzed samples increased as the Mn concentration increased in the synthesis reaction. Conclusion: The addition of Mn as an intended doping element increased the crystallite size and the polycrystallinity of the synthesized hydrated forms of tin oxide (II) or (IV). Additionally, it also promoted the formation of 2D nanostructures made of SnO2 nanoparticles.

Background: The evolution of environmentally-safe methods for treating hazardous chemicals in wastewater, particularly urban and industrial wastewater, has increased interest over recent years. The chromium-containing wastewater is produced by industries from steel, metallurgical, electroplating, chemical, refractory, leather tanning, dye manufacturing, mining, cementing, textiles, etc. Consequently, advanced techniques are essential for treating chromium-polluted water. Objective: The prime objective of this effort was to assess the adsorption performance of nanoTiO2 (nanoparticles of average crystallite size 19.15 nm) doped strong base anion exchange resin (TDTulsion) for Cr (VI) to that of the host Tulsion A-62 (MP). Methods: The tests were carried out in batches in the temperature-controlled water bath shaking unit, with 30 ml of the aqueous solution containing Cr (VI) and a certain amount of resin being stirred for 6 hours at 303 K. Using a standard diphenylcarbazide (DPC) procedure at 540 nm, the solution was spectrophotometrically analyzed for Cr (VI). Results: The majority of the Cr (VI) ions are adsorbed by the anion exchange resins Tulsion A- 62(MP), and TD-Tulsion is in the pH range of 4.0 to 5.0. The maximal sorption capacity of Cr (VI) was established to be 181.5 and 204.8 mg/g for Tulsion A-62(MP) and TD-Tulsion, respectively. Conclusion: The TD-Tulsion has a substantially better adsorption capacity than Tulsion A-62(MP) under similar conditions. The outcomes show that modifying anion-exchange resin with nano titanium dioxide improves adsorption performance in Cr (VI) removal from drinking water and contaminated water.

Background: The fabrication of polymer fibre blends has gained much attention for the development of innovative nanomaterials. Polymer fibre blends are nanomaterials with different functionalities and properties such as a sizeable surface-to-area ratio, high porosity, flexibility, and stability. The focus of this study was to produce zein/PVA fibre blends using the electrospinning technique and varying parameters such as concentration and applied voltage. The two parameters are key driving factors for the production of fibres. Zein as a natural polymer has challenges in developing fibre materials which require artificial polymer like PVA to create a good blending mixture for electrospinning. Methods: The zein/PVA nanofibre blends were fabricated using the electrospinning technique. The FE-SEM (Leo, Zeiss) was used to study the surface morphologies of the zein/PVA nanofibers blends. The optical properties of the nanofibre blends were determined using the UV-vis spectrophotometer and the chemical structure and composition of zein/PVA nanofibers blends were studied using Thermo Scientific Nicolet iS50-FTIR spectrometer, universal ATR with the diamond detector. Results: The SEM images showed smooth zein/PVA ribbon-like nanofibre blends of 90/10, 80/20, 70/30, 60/40, and 50/50. SEM images of zein/PVA (80/20) electrospun at 25 kV were obtained to be the maximum fibre yield due to zein/PVA compatibility, increased conductivity, and enhanced fibre formation. The optical properties (absorption spectroscopy) suggested that the zein/PVA (80/20) fibre blend was miscible, and the FTIR spectra confirmed their functional groups. Therefore, the characterization results showed that the polymer blended solutions concentration and applied voltage increment affected fibre size distribution and morphology. Conclusion: Optimizing concentration and applied voltage successfully produced smooth, uniform bead-free zein/PVA fibre blends as parameters are increased.