International Journal of Nano Dimension
Volume:14 Issue: 1, Winter 2023

In this review article, the implementation of nanomaterials such as metal oxides and their composites, carbon nanotubes, dendrimers, and polymer nanocomposites in wastewater decontamination have been discussed. Nanomaterials have a lot of potentials, due to their high pollution sensing ability and larger surface area. Nanomaterials are ideal for eliminating harmful heavy metals and eradicating severe infections spreading microorganisms, organic waste and inorganic contaminants from the environment. The article reviews recent developments in wastewater treatment using various nanomaterials. Nanotechnology has resulted in multiple effective nano techniques for environmental remediation such as photocatalysis, nano adsorption and nanofiltration, which are more exact and accurate in eradicating recalcitrant. Novel semiconductor photocatalysts, nano adsorbents, nanocomposites, and other nanostructures have been used to overcome these difficulties and achieve maximal performance at a low cost. This review provides the techno-functional applications of nanomaterials in wastewater remediation.

Quantum Dots are a group of semiconductors nanomaterials whose size is about less than 10 nm exhibiting unique optical and electric properties which impart different advantages in terms of wide and continuous absorption spectra, narrow emission spectra, high quantum yield, long fluorescence lifetimes, and high photostability. Based on the unique properties of quantum dots have a variety of applications. This review informs about quantum dots structure, properties of quantum dots, surface modification of quantum dots for biocompatible, synthesis process and its important application like labeling cell structure and FRET (Fluorescence resonance energy transfer). Quantum dots as bio-sensors, bio-marker, and bio-imagine are used in many therapeutic systems. Several attractive applications have been observed with supramolecular compounds: Calix-4 arenes derivatives with quantum dots in the field of medical science.

The effect of milling process on TiO2</sub> nanopowders and functional properties of TiO2</sub> coated cotton fabric was investigated. The XRD analysis reveals that the milled TiO2 </sub>nanopowders reduce its size in Nano scale when milling time increases. SEM analysis reveals that the milled TiO2</sub> powder shows a seed-like structure. FTIR spectra show the presence of the functional groups in milled TiO2</sub> nanopowders and TiO2 </sub>coated cotton fabric. The hydrophobic test exhibits that the 100 and 125 hours of milled TiO2</sub> nanopowders coated cotton fabric has 70% water repellency.  The bursting strength (shearing stress) of TiO2</sub> coated cotton fabric also indicates an appreciable value of about 503.6 Kpa. TiO2</sub> nano finishing of cotton fabric can eliminate up to 99.99% of Staphylococcus aureus and Klebsiella pneumonia bacterial strains, which would be suitable for sports wears and surgical clothes.

In the current study, a novel S-scheme heterojunction photocatalyst was fabricated through a simple hydrothermal method from CeO2</sub> nanoparticles and WO3</sub> nanoplates in presence of tragacanth mucilage as natural surfactant. The prepared heterojunction photocatalyst was used for degradation of Nitenpyram insecticide under visible light irradiation. The successful synthesis of the heterojunction samples was confirmed by FESEM, XRD, PL, DRS, and Mott-Schottky analysis. The results showed that, the photocatalytic performance of the CeO2</sub>/WO3</sub> heterojunction sample was higher than that of the pure WO3</sub> and CeO2</sub> samples. The highest photocatalytic activity was obtained for the sample with 30 wt% CeO2</sub> content, which has the reaction rate constant of 0.017 min-1</sup>. The improved photocatalytic activity of the nanocomposite sample could be related to the efficient separation of the photoinduced electron-hole pairs at the interfaces of WO3</sub> and CeO2</sub>, and enhanced visible light harvesting. Furthermore, according to the active species trapping tests and Mott-Schottky measurements, hydroxide radical was determined as the main active species for degradation of Nitenpyram insecticide, and a S-scheme charge transfer mechanism revealed to be responsible for the enhanced photocatalytic performance.

Recently, with the increase in diseases caused by bacterial and viral infections, the need for antibacterial agents has widely increased. On the other hand, with the development of drug resistance to organic groups of antibiotics, new antibiotics have attracted the attention of researchers because new methods are needed to reduce the activity of bacteria. Nanotechnology is increasingly being used for medical applications and is useful as an approach to kill or reduce the activity of various microorganisms. Metal oxides are considered for medical applications, especially as antibacterial agents, due to their potential advantages and suitable nanoscale properties. In this study, the electric discharge method was employed for the preparation of the iron oxide nanoparticles (IONPs) and iron-zinc oxide nanoparticles (IZONPs). As the IONPs and zinc oxide nanoparticles (ZONPs) attack various gram-positive and gram-negative bacteria by different mechanisms, it seems that the simultaneous use of these oxides can effectively kill various bacteria in outdoor and indoor media. The synthesized nanoparticles were characterized via XRD, UV-Visible, FE-SEM, EDS, HR-TEM, and TEM techniques. The obtained results showed that the IZONPs with mean particles size between 11 and 33 nanometers have successfully been synthesized in various experimental conditions. Also, the antibacterial properties of these nanoparticles were evaluated and the particles showed antibacterial properties against both gram-positive and gram-negative bacteria.

In this study, we report the synthesis of magnetite (Fe3</sub>O4</sub>) nanoparticles using Catha Edulis plant leaf extract as bioreducing agents and investigation of its efficiency as an adsorbent for hexavalent chromium Cr(VI) removal from aqueous solutions. The synthesized NPs were characterized using X-ray diffraction (XRD) spectroscopy, Fourier Transforms Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Ultraviolet-visible (UV-Vis) spectroscopy, and thermal analysis (TGA-DTA). The XRD result revealed that the phase structure of Fe3</sub>O4</sub> NPs was cubic face-centered with crystallite sizes of 12.1 nm, 14 nm, and 9 nm for metal to plant extract ratios of 1 : 1, 2 : 1, and 1 : 2  respectively. UV-Vis DRS analysis confirmed band gap energy of synthesized NPs was in the range 2.0-2.5 eV. Batch adsorption experiments were carried out to evaluate the effect of different parameters such as pH (3-10), adsorbent dose (250mg/L – 1250mg/L), initial concentration of adsorbate (20mg/L - 60mg/L), and contact time (30-120 min) on adsorption efficiency of the NPs at room temperature. The study revealed that the synthesized magnetite adsorbent exhibited  </sub>Cr (VI) removal efficiency of about 98.6% at optimized conditions of adsorbent dose of 1000 mg/L, pH 5, initial concentration of Cr(VI) 20 mg/L, and contact time of 60 min. The experimental data were best fitted to the Freundlich adsorption isotherm model (R2</sup> = 0.98341). Moreover, the mechanism of adsorption was in good agreement with pseudo 2nd</sup> order kinetics (R2 </sup>= 0.98188). The results suggested that the biosynthesized Fe3</sub>O4</sub> nanoparticles have the potential for the removal of hexavalent chromium ions from aqueous solutions.

In this paper, we optimize the electrical characteristics of Nano-scale symmetric double-gate metal oxide semiconductor field effect transistors (DG-MOSFETs) for digital applications using a genetic algorithm. We use a single-objective genetic algorithm to optimize the threshold voltage (Vth</sub>) with a distinct analytical relationship. The optimization of the threshold voltage is accomplished for three cases with considering two structural variables of the oxide thickness (tox</sub>), the channel thickness (tsi</sub>), and the channel doping density (Na</sub>). The fourth case of optimization is done with considering these three variables. Comparison of these four cases illustrates that the best threshold voltage is 0.15 V for a channel doping concentration of 1.2×10 10 </sup>cm-3</sup> and an oxide thickness of 1.49 nm. In addition, we optimize the OFF-current criterion based on the gate oxide thickness, the channel thickness, the channel doping concentration and the channel length and width. The optimization processes of the device are validated by simulating in SILVACO software. Furthermore, we use the two-objective genetic algorithm with the threshold voltage and the OFF-current objects for four structural variables including the gate oxide thickness, the channel layer thickness, and the channel length and width. This process is applicable to digital circuit design. To evaluate the accuracy of the proposed device optimization, the optimized device and other situations are simulated in SILVACO simulator. The optimized device illustrates the best treatment.

In this report, we </strong>intend to </strong>synthesize iron oxide (Fe2</sub>O3</sub>), erbium oxide (Er2</sub>O3</sub>), and a composite of erbium oxide/iron oxide (Er2</sub>O3</sub>/Fe2</sub>O3</sub>) nanoparticles (NPs) by a microwave irradiation technique. After the synthesis, we explore the various physicochemical properties of the sample with the help of various systematic characterization techniques. First, the prepared sample has been subjected to XRD for determining the crystal structure. Then, we confirm the functional groups of the sample with the help of FTIR. Further, we analyze the absorbance and the band gap with a UV-Vis spectrometer. Besides, we also investigate the microbial studies, namely, the anti-bacterial and the anti-fungal. Finally, we also analyze the response of human breast cancer cells when they are exposed to iron oxide (Fe2</sub>O3</sub>), erbium oxide (Er2</sub>O3</sub>), and a composite of erbium oxide/iron oxide (Er2</sub>O3</sub>/Fe2</sub>O3</sub>) nanoparticles (NPs) with MDA MB 231 by MTT assay.