Showing papers in "Nano-Structures and Nano-Objects in 2020"

Polymer grafted carbon nanotubes—Synthesis, properties, and applications: A review

Abstract: Carbon-based nanomaterials such as carbon nanotubes (CNTs) have become the most promising materials in biomedical, electronic and aerospace applications. When added to polymers, they can enhance the properties and the utility of the polymers to a large extent. This is because of their superior thermo-mechanical and electrical properties which can be effectively transferred to the resulting composites with their proper dispersion in the polymer matrix. But the uniform dispersion of CNTs in various polymer matrices is the major challenge faced by scientists. This paper critically reviews the different chemical strategies adopted for grafting polymers onto the CNTs which ultimately leads to better polymer-filler interaction and optimum filler dispersion for the development of high-performance polymer nanocomposites. This review also discusses the synthesis, properties, and applications of polymer grafted CNTs and their composites.

Synthesis of barium ferrite nanoparticles using rhizome extract of Acorus Calamus: Characterization and its efficacy against different plant phytopathogenic fungi

Abstract: A green technology for producing barium ferrite (BaFe12O19) nanoparticles (BFNP’s) using Acorus Calamus rhizome extract was realized. To confirm the phase of magnetoplumbite structure without any impurities, the method of powder X-ray diffraction was performed using the Rietveld analysis and the FullProf program with the P63/mmc (No. 194) space group. Unit cell parameters were a = 5.8902(2) A and c = 23.2103(7) A. According to Scherrer’s calculations, the average crystallite size was from ∼ 32 to ∼ 35 nm. The results of scanning electron microscopy confirmed that synthesized BFNP’s are tightly packed and have an average grain size of ∼ 70 nm. Raman and IR active modes predicted by group theory are observed at ∼ 175 cm−1 and ∼ 677 cm−1, which corresponds to the presence of a spinel structure and trigonal pyramidal position in barium hexaferrite. It was established that the spontaneous magnetization is ∼ 52 emu/g and coercive force is ∼ 440 mT at room temperature. In vitro studies were performed to evaluate the antifungal activity of BFNP’s against various plant pathogenic fungi, namely: Fusarium oxysporum, Alternaria alternata, Colletotrichum gloeosporioides and Marssonina rosae. The antifungal effect of BFNPs was determined for different phytopathogenic fungi at a multiple dose of 200 mg/L, 300 mg/L, 400 mg/L, 500 mg/L and 600 mg/L. The maximum inhibition of mycelial growth (76.67%) was detected at 600 mg/L against the growth of Fusarium oxysoporum mycelium. The data obtained show that BFNP’s synthesized using Acorus Calamus rhizome extract can be applied as a potential antifungal agent.

Silver and copper oxide nanoparticles-decorated graphene oxide via pulsed laser ablation technique: Preparation, characterization, and photoactivated antibacterial activity

Abstract: Graphene oxide, silver and copper oxide nanoparticles display photoactivated antibacterial behavior owing to their ability to generate charge carriers via light exposure. In this work, silver nanoparticles (AgNPs) and copper oxide nanoparticles (CuONPs) were embedded through graphene oxide (GO) using laser ablation technique. The microstructural behavior of the synthesized compositions has been investigated via XRD and TEM. The optical properties were studied by (UV–Vis), while the antibacterial properties were investigated in addition to the cell viability towards normal cell line (HFB4) in vitro. The antibacterial activity of GO was enhanced significantly with addition nanoparticles; by meaning, the inhibition zone enlarged from 5.4 mm with pure GO to be around 11.2 mm against E. coli with contribution of CuONPs. This trend of enhancement suggests that GO could be a great platform for different kinds of photo-activated antibacterial to be recommended for versatile biomedical applications.

Ultrasound assisted preparation of rGO/TiO2 nanocomposite for effective photocatalytic degradation of methylene blue under sunlight

Abstract: In the present work, well known Hummers–Offeman method was employed for production of graphene oxide (GO) and in-situ deposition of TiO2 nanoparticles on prepared GO in presence of ultrasonic irradiations to get reduced graphene oxide-TiO2 (rGO/TiO2) nanocomposite. The structural and morphological analysis of synthesized photocatalysts was accomplished with UV–Vis, XRD, FT-IR, Raman Spectra, EDAX, XPS and TEM analysis. The absorption peak at 234 nm shows redshift to 285 nm which confirms the reduction of GO to rGO. XRD analysis of the prepared composite confirmed the presence of the combination of anatase and rutile phases of TiO2. TEM images revealed that large amount of round-shaped TiO2 nanoparticles in size range of 3 to 5 nm were consistently deposited on the rGO sheet due to ultrasonic irradiations. Further, effectiveness of the prepared nanocomposite as a photocatalyst was examined with the decolourization of methylene blue (MB) dye in sun light. The effect of catalyst loading and pH on MB dye degradation was examined. The results indicated that the percent degradation of selected MB dye enhanced at higher catalyst loading and also a higher pH favoured the degradation. The maximum MB dye degradation was observed to be 91.3% within 30 min for pH value of 13.2 and photocatalyst dosage of 2 g/L. Further, the kinetic studies established the pseudo first-order reaction kinetics for the photocatalytic decolourization/degradation of MB dye.

Structure-directing property and growth mechanism induced by capping agents in nanostructured ZnO during hydrothermal synthesis—A systematic review

Abstract: Zinc oxide nanoparticles (ZnO NPs) have become a topic of comprehensive research from the past many years due to their excellent optical, physical and chemical properties, which gives rise to numerous applications. The challenge, however, in ZnO NPs synthesis is the agglomeration of particles along with the design of their desired morphology and size. To overcome such challenges and to obtain application specific size and morphology of ZnO NPs, organic capping ligands are extensively used. The current review focuses on this aspect, wherein, a detailed analyses on the role of common capping agents during ZnO NPs synthesis has been provided. Keeping in view the effect of synthetic processes which contribute to size and morphology alteration of ZnO NPs, focus is particularly paid on hydrothermal synthesis because of its several advantages. Through this review, readers may get an idea about the type of ZnO NPs’ morphology with a particular capping agent. For instance, most surfactants and amino acids direct the formation of 2-D rod-like morphology of ZnO NPs, while polymers and polysaccharides may lead to the formation of various ZnO NPs’ morphologies, such as, nanospikes, microstars, etc. Further, the theoretical basis governing the rational design of NPs possessing modelled and controlled size, morphology and microstructure has also been discussed. To the best of Author’s knowledge, no previous reports have focused on these aspects. Moreover, the various applications of ZnO NPs have also been briefly discussed.

Prospective of nanotechnology in degradation of waste water: A new challenges

Abstract: In the current scenario, the conservation of environment is an urge. Among various environmental hazards, the knocking area is waste water treatment. Scientists are constantly engaged in finding the advanced technology with high proficiency and low investment. One such technique called as nanotechnology has interesting application in the field of waste water treatment. However, information accessible is restricted. The present text reviews the application of various nano-materials for wastewater treatment techniques. The five main classes includes: First, Nano adsorbents like metal oxides, applied usually for removal of heavy metals. Second, nanomaterials of carbon used for effective adsorption and conduction process. Third, graphene-based nanoparticles for environmental remediation. Fourth, nanotubes have been used for effective removal of pollutants by means of, hybrid Nano membranes, Nano fibers and carbon nanotube membranes. Fifth is recyclable nano composites, mats, beads in water decontamination. Finally, some zero valent Nano sized metals showing strong adsorption capability and operational simplicity. This paper discusses the application of nanomaterials in wastewater treatment. Such nanomaterial’s which affordable, eco-friendly are, and efficiently work at large scale is the need of hour.

Potential of cobalt and cobalt oxide nanoparticles as nanocatalyst towards dyes degradation in wastewater

Abstract: We herein report the morphology and photocatalytic properties of Co and Co3O 4 nanoparticles synthesized using microwave and reductive chemical heating methods. The synthesized nano-scale particles were characterized using UV–visible (UV–Vis) absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction spectroscopy (XRD), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). Photocatalytic degradation of murexide dye and erichrome blak-T (EBT) dye in wastewater in the presence of sunlight was investigated using the synthesized nanoparticles. Chemically synthesized Co-nanoparticles gave highest degradation efficiency (43.6%) towards murexide dye at 25 mg loading and 40 mins exposure time, while Co3O4 nanoparticles (microwave synthesized) gave the highest degradation efficiency (39.4%) at 10 mg loading and 40 mins sunlight exposure time in EBT. A higher photodegradation efficiency is postulated at a longer exposure time under sunlight irradiation. The study therefore concluded that the microwave synthesized nanoparticles would be preferred for remediation of dyes containing wastewater since it is greener, faster to make, cheap and gave photocatalytic degradation efficiency that compared favourably with that of the chemical method.

Graphitic carbon nitride-based catalysts and their applications: A review

Abstract: Graphitic carbon nitrides (g- C 3 N4), which possess distinctive graphite-like structure, and their composites have found relevance in several applications. This is attributed to their favorable band gap, metal-free nature, high thermal and photo-stability. Other properties including good mechanical properties, chemical inertness, non-toxicity, good biocompatibility and excellent electroluminescent properties have also accentuated their increased applications in different areas. Entirely new properties are obtained when they combine with other nanomaterials to form nanocomposites, and all these properties are now being explored for various benefits. This review highlights the historical background of g- C 3 N4, the recent progress in the application of the materials in its pristine form, the composite with different inorganic compounds and nanomaterials. Particular attention is given to their applications in nitrogen fixation, as reference material for differentiating oxygen site, in energy storage device, sensing, chemical synthesis, water splitting, photocatalytic heavy metal ions reduction, environmental remediation from pollutants and medicine. The properties were highlighted and different applications were discussed, with the aim of exploring other new areas of applications of g- C 3 N4. The different routes that have been utilized for the synthesis of g- C 3 N4, the various nanostructures obtained and the analytical techniques that are required for their characterization were discussed. Finally, in the interest of the recent development and focus on photo enhanced process, diverse ways of enhancing the photocatalytic activities of g- C 3 N 4 and its composites were investigated.

Nano-based antiviral coatings to combat viral infections

Abstract: In the recent past, epidemics and pandemics caused by viral infections have had extraordinary effects on human life, leading to severe social and financial challenges. One such event related to the outbreak of the SARS-CoV-2 virus has already taken more than 917,417 lives globally (as of September 13, 2020). The nosocomial route of viral transmission has also been playing a significant role in the community spreading of viruses. Unfortunately, none of the existing strategies are apt for preventing the spread of viral infections. In order to contain the viral transmission, the principal target would be to stop the virus from reaching the otherwise healthy individuals. Nanomaterials, due to its unique physical and chemical properties, have been used to develop novel antiviral agents. In this review, we have discussed several nanotechnological strategies that can be used as an antiviral coating to inhibit viral transmission by preventing viral entry into the host cells.

Cancer theranostic applications of MXene nanomaterials: Recent updates

Abstract: MXenes have been emerging as one of the most versatile types of nanomaterials over the last decade due to their exciting physical and chemical properties. Thanks to their exciting biocompatibility and tunable electronic and optical properties, the search of promising biomedical applications of MXenes has reached on cancer theranostics. Literature shows valuable results where MXenes have been employed in vitro and in vivo cancer models. This involves drug delivery systems, sensoring probes, auxiliary agents for strategies as photothermal therapy and hyperthermia. This mini review summarizes the works on MXenes reported for cancer theranostic applications on various in vitro and in vivo models. It includes various types of MXene systems as Ti3C2, Nb2C, Ti2C in conjugation with drug molecules, metallic nanoparticles and other macromolecules. Finally, the future possibilities of the scenario were also discussed in detail.

Enhanced visco-elastic and rheological behavior of epoxy composites reinforced with polyimide nanofiber

Abstract: High performance epoxy composites are now a days a must in several industrial applications. In the present work electrospun polyimide (PI) nanofibers with excellent thermal and mechanical properties was used as a reinforcement in epoxy matrix via a simple mechanical mixing followed by thermal curing method. Well defined electrospun nanofibers of aromatic polyimide (PI) were successfully prepared from electrospinning Poly (amic acid) (PAA) and subsequent thermal treatment. The fiber morphology was analyzed using Transmission electron microscopy (TEM) and Atomic force microscopy (AFM). PI/epoxy nanocomposites with different PI loadings were prepared using chopped PI mats. The dynamic mechanical performance of these PI/epoxy composites was investigated to determine the influence of PI fibers in reinforcing the epoxy matrix. The fracture toughness of these composites displayed a note worthy improvement of 20 % at 1 w% loaded samples and the surface of the fractured samples was investigated by Scanning electron microscope. The rheological properties of these systems show a tremendous increase in the storage and loss modulus when compared to neat systems. In addition flow models were employed to model the rheological data and the comparison was made with the experimental data.

Nanostructural computation of 4D printing carboxymethylcellulose (CMC) composite

Abstract: Additive manufacturing of complex structures with functional and programmable attributes of Fused deposition Method (FDM) of 4D printing enables complex and innovative designs with shape memory properties. However, several challenges still exist in successfully realising FDM of 4D printing due to its high complexity, fragility and control of temperature for a specific change in the shape of specific materials. This study focuses on microstructure, the calculation in the creation of hydrogel, cellulose, and ink that combines sound waves to create shape memory properties of hydrographic cellulose compositions in 4-dimensional printing. The high amounts of hydrocolloid cellulose fibres are used for carboxylic cellulose particles, carboxymethyl cellulose (CMC) and matrix fibre decay compound 5.0% shapes memory. Thermoplastic shapes are also used in composite coagulation processes to create a mophological charaterisation composite of 3D-printing polymer structure based on full-area measurement technology, which is the change of particles. Investigation of the nanostructure of CMC composite particle in 4D surface structure, roughness, waviness profile of the specimens ware extracted and analysed. Typed A complex workshop structure demonstrates the capability of sonication used in 3D printing. The most important property is the content of cellulose in the form of final materials is the volume of cellulose in a sonicated composite.

Self-healing polymers: Synthesis methods and applications

Abstract: Clays have numerous applications in a variety of applications including engineering, medical and civil areas. The wide applicability of clays is attributed to their useful physico-mechanical as well as biomedical applications, since they are readily available, nontoxic to human body and environment, low cost and having kneading, swelling, adsorption of properties for metal ions. Industrial sectors in different fields are greatly dependent on the usage of different clays, but the cracks or defects or damaged areas present in clays restrict their practical applications. In order to overcome these problems, various polymeric materials have been developed through different strategies to heal the cracks or repair the damaged areas of clays, and improve their properties and potential usage in various applications. This review will address several aspects such as preparation, structure–property relationships, properties of different types of clays and self-healing polymers, healing process of cracks in clays using polymers, crack healing mechanism, test methods of healing efficiency, properties (e.g. structure, hydraulic conductivity, swelling nature, mechanical and rheology) of clays before and after healing of cracks, and their applications.

Structural and photoluminescent investigations of SrAl2O4:Eu2+,RE3+ improved nanophosphors for solar cells

Abstract: The long afterglow green emitting materials were prepared by fast gel-combustion procedure (600 °C) using urea as fuel. This paper reports the improvement in photoluminescence intensity and persistency of Eu 2 + incorporated long-persistent SrAl2O4 nanophosphors by the addition of rare earth ions (Dy 3 + , Pr 3 + , Y 3 + ) as codopants. The materials were investigated using X-ray diffraction (XRD), Fourier transformation infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. X-ray diffraction analysis exhibited the formation of pure SrAl2O4 phase with monoclinic crystal system and space group P2 1 . FTIR spectra were used to determine the stretching and bending modes of vibrations to confirm the formation of metal–oxygen bonds. The microstructures were observed using SEM and TEM analysis. For the synthesized strontium aluminate phosphors, the photoluminescence characteristics including excitation, emission and decay kinetics were also examined. PL emission spectra, recorded at the excitation wavelength of 362 nm, exhibited the characteristics peak at 510 nm corresponding to the parity allowed 5d–4f electronic transition of Eu 2 + ions. The phosphorescence intensity of the materials were greatly enhanced on addition of codopants (Dy 3 + , Pr 3 + , Y 3 + ), without any change in the position of the peak in spectra. The outcomes of these investigations made the focused materials worthy for the applications in the solar cells and lighting technology.

Comparative analysis of platinum nanoparticles synthesized using sonochemical-assisted and conventional green methods

Abstract: Platinum nanoparticles (Pt NPs) were synthesized, through sonochemical and conventional methods, using the extract from Prosopis farcta fruits (PFFs) as a reducing agent and stabilizer. The structure, morphology and colloidal stability of Pt NPs synthesized by both methods were characterized and compared. A Vibra-Cell ultrasonic solid horn with tip size, frequency, a power output of 1 2 inch, 20 kHz and 750 watts, respectively, were used in the sonochemical synthesis of Pt NPs for 30 min. The formation of amorphous or crystalline Pt NPs is attributed to rapid heating/cooling cycles of the cavitation microbubbles generated by the sonication. The purity, uniformity and crystallinity of Pt NPs synthesized by the sonochemical method were shown to be better than those obtained from the conventional method. The Pt NPs also exhibited smaller particle size with higher colloidal stability and hydrodynamic size. The results confirm that the irradiation power of the sonochemical method enhances the crystalline properties of nanoparticles and hinders their agglomeration. Therefore, the sonochemical method can synthesize Pt NPs with better physicochemical properties compared to conventional methods.

Efficient removal of Cu (II) by SnO2/MWCNTs nanocomposite by pulsed laser ablation method

Abstract: In this work, SnO2 nanoparticles were synthesized and decorated multiwalled carbon nanotubes (MWCNTs) in a simple one-pot step by pulsed laser ablation of Sn plate immersed in liquid media from functionalized MWCNTs to be applicable in the water purification as adsorbent material for removal Cu (II) metal ion from aqueous solution. The crystallinity, surface morphology, the molecular interaction, the elemental analysis, and thermal analysis of the interaction between MWCNTs and SnO2 were illustrated by different techniques as XRD, SEM, TEM, EDX, FT-IR, Raman, and TGA. The results revealed that the embedding of MWCNTs with SnO2 nanoparticles helps to enhance the performance of the adsorption process. The efficiency of the adsorbent nanocomposite to uptake Cu (II) from the water was studied via a number of effective parameters (pH value, adsorbent concentration, and contact time) to inform the best condition that could be used from this composite for Cu (II) removal from the aqueous solutions.

Controlled delivery of tetracycline hydrochloride intercalated into smectite clay using polyurethane nanofibrous membrane for wound healing application

Abstract: This study reports application of electrospinning for controlled drug delivery by using polyurethane monolithic nanofibrous web. The endeavor of this study was to explore the effects on release, antimicrobial activity, and morphological behavior of drug–nanoclay intercalates vis-a-vis direct drug inclusion in the form of nanofibrous structures. Antibiotic drug, tetracycline hydrochloride was incorporated into montmorillonite clay interlayer spacing and then embedded into the synthetic polymeric nanofibrous structures. In vitro release study was conducted to assess the release characteristics. Disk diffusion experiment was organized to observe antimicrobial activities and finally human dermal fibroblast cells were grown on the nanofibrous web to address morphological behavior. The results showed that the nanoclay performed as a better way in the form of sustained drug release carrier. The produced electrospun nanofibrous webs could provide broad spectrum antibacterial activities beneficial for topical applications. The fibroblast cell growth on the nanofibrous web caused proliferation to result a mesh like structure which would certainly have a positive effect on wound healing.

Ultrasonic cavitation: An approach to synthesize uniformly dispersed metal matrix nanocomposites—A review

Abstract: Metal matrix nanocomposites (MMNCs) have become noticeable as a significant class of materials for structural applications exclusively in the automobile and aerospace sectors. The growth of cost effective mass production technique of MMNCs with essential operational and geometrical flexibilities is still a great challenge. Innovative synthesis process for uniform dispersion of nanoparticles in metal matrix has sparked considerable interest among the material scientists all over the globe. In the last two decades, a trend has been established in this direction to synthesize oxide and novel carbide based nanocomposites. In this process, a lot of emphasis is given in recent times to increase the physical and mechanical properties of the nanocomposites. The physical and mechanical properties of oxide or carbide based nanocomposites completely depend upon the fabrication technique and on the dispersion of nanoparticles in the metal matrix. Even though a lot of synthesis techniques have been adopted from solid state mixing to powder metallurgy route; it is not possible to achieve uniform dispersion of nanoparticles throughout the matrix. In the present review, we have emphasized the basic consideration for the synthesis of metal matrix nanocomposites and the advantages & disadvantages of various techniques. A new instrumentation technique i.e., ultrasonic cavitation based processing is found to be the most promising method for manufacturing of MMNCs with almost uniform distribution of nanoparticles. Alumina dispersed aluminium nanocomposites can be fabricated without any segregation by ultrasonic cavitation based processing which has been explained extensively. In addition to this, the structural and mechanical properties of alumina dispersed aluminium metal matrix composites synthesized by ultrasonic cavitation technique have been discussed.

CoCu2O4 nanoflowers architecture as an electrode material for battery type supercapacitor with improved electrochemical performance

Abstract: In this study, an efficient electroactive material of CoCu2O4 with nanoflowers-like architecture has been developed by simplistic and low-cost hydrothermal technique without binders. The CoCu2O4 nanoflowers architecture provides large surface area and boosts the rating of ion accessibility and the speed of electrons transfer and thus enhances the electrochemical activities. In aqueous electrolyte, the present CoCu2O4 nanoflowers electrode exhibited a high specific capacity of 354.12 C g−1 at 2 A g−1. After 3000 long and continuous charging/discharging cycles, 97.3% of the initialing capacity has was retained. This super-active electrochemical properties of the CoCu2O4 nanoflowers architecture are mainly attributed to the enhanced surface area and to the improved ion transportation, which make it a promising candidate as an electrode material for energy storage supercapacitors.

Selective dehydrogenation of isopropanol on carbonized metal–organic frameworks

Abstract: Alcohol dehydrogenation to carbonyl compounds and hydrogen ( H 2 ) gas offers a green and sustainable method for producing H 2 and the synthesis of various pharmaceuticals and fine chemicals. However, it is a challenge to acquire remarkable selectivity toward carbonyl products. Herein, CuO@C catalyst displays high dehydrogenation over dehydration reaction for isopropanol. CuO@C core–shell was synthesized from the carbonization of metal–organic frameworks (MOFs) via a single step without the need for incorporating an external source of carbon. CuO@C showed high selectivity (100%) and increased conversion (100%) of isopropanol to acetone and hydrogen via dehydrogenation. It exhibited high stability under the reactant flow for a long time and reusability for several cycles. A mechanism of the dehydrogenation was also highlighted using different analytical methods, including X-ray diffraction (XRD), electron diffraction (ED), Fourier transform infrared (FT-IR), and high-resolution transmission electron microscopy (HR-TEM).

Modification of structural and magnetic properties of Co0.5Ni0.5Fe2O4 nanoparticles embedded Polyvinylidene Fluoride nanofiber membrane via electrospinning method

Abstract: Ferrite nanoparticles have garnered significant attention due to their remarkable ferromagnetic properties. However, the functionality of the ferrite nanoparticles can be enhanced with the development of nanofiber membranes. This helps to control the surface, structural and magnetic properties of the composite nanofiber membrane. Herein, we report the fabrication of novel nanofiber membrane containing Co 0.5 Ni 0.5 Fe2O4-Polyvinylidene Fluoride (PVDF) via electrospinning method. The Co 0.5 Ni 0.5 Fe2O4 nanoparticles were synthesized with the help of sol–gel combustion method. Investigations on the effect of Co 0.5 Ni 0.5 Fe2O4 nanoparticles embedded within PVDF polymer nanofiber membrane on structural, morphological and magnetic properties are discussed. XRD line profile analysis revealed cubic spinel structure of the Co 0.5 Ni 0.5 Fe2O4 nanoparticles To determine the crystallite size of the samples; Scherrer, Williamson–Hall (W–H), and Size-Strain plot (SSP) were carried out with the help of XRD spectra. The crystallite size of the nanoparticles reduced as they were embedded within PVDF polymer. FTIR studies confirmed that the presence of Co 0.5 Ni 0.5 Fe2O4 pristine nanoparticles within the polymeric nanofiber membrane was accountable for the enhanced β -phase bands which makes a significant effect on the ferroelectric properties of the nanofiber membrane. In addition, the VSM technique was used to study the ferromagnetic properties. The enhanced remnant magnetization and saturation magnetization of the nanoparticles was responsible for magnetic nature of the non-magnetic polymer PVDF.

Bioinspired fluorescence carbon quantum dots extracted from natural honey: Efficient material for photonic and antibacterial applications

Abstract: Fluorescent carbon quantum dots were extracted from natural honey using the hydrothermal approach. The XRD and HRTEM investigations confirm the morphology of the carbon quantum dots (CQDs) are spherical shape with a diameter of 8.29 nm. The FTIR and XPS analysis indicate the effective incorporation of nitrogen and sulfuratoms into the CQDs. The sample demonstrated the blue fluorescence by the UV-light illumination ( λ ex = 365 nm ). When excited at 350 nm, the quantum yield of honey CQDs was found to be ∼ 4.192 % at the emission wavelength (431 nm). Crucially for the first time, the existing honey CQDs generates a strong nonlinear optical response relative to some semiconductor QDs. The non-linear optical characterization was investigated utilizing the Z-Scan method. These CQDs exhibit self-defocusing nonlinearity and strong nonlinear performance in the absorption. Also, the agar well diffusion method used to investigate the antimicrobial efficacy of the CQDs against the foodborne pathogens. It is inferred from the existing observations that honey CQDs have been used as effective optoelectronic devices and antimicrobial agents.

Nanoparticle technology for separation of cellulose, hemicellulose and lignin nanoparticles from lignocellulose biomass: A short review

Abstract: This article addresses particle size reduction technologies currently available and their potential application in bioenergy production from waste biomass. It is believed the reduction of the particle size of biomass wastes to nano-scale will have a significant impact on the quality, quantity, and price of biofuels. Currently, these technologies have not been developed for commercial application due to lack of efficiency. They can only function on small scale operations with high energy consumption. Advancing particle size reduction technologies to produce nano-scale particles at a commercial level is an emerging need.

An efficient photocatalytic degradation of organic dyes under visible light using zinc stannate (Zn2SnO4) nanorods prepared by microwave irradiation

Abstract: Ternary compounds are found to be more thermally stable with high electron mobility and hence higher efficiency towards sensing, photocatalysis and optoelectronic devices as compared to binary compounds (ZnO, SnO2). An elegant approach was made to synthesis one dimensional zinc stannate (Zn2SnO4) using microwave technique, which is energy efficient, less time consuming and economically viable for large scale production. The cubic spinel structure was confirmed using X-ray diffraction (XRD) and rod shaped morphology was observed on field emission scanning electron microscope (FESEM). Nanorods obtained were pure, monodispersed and uniform. Structural composition, oxidation state and binding energy were studied using X-ray photoelectron spectroscopy (XPS). Optical properties were studied using UV–Vis and photoluminescence (PL) spectroscopy. Band gap was found to be 3.74 eV, which shows quantum confinement and was calculated using Tauc’s equation. Moreover, the growth mechanism is discussed with role of microwave radiation over conventional heating methods. Under visible light irradiation, Zn2SnO 4 nanorods have excellent photocatalytic activity for the degradation of cationic rhodamine dye (60 mins, 98%) and anionic methyl orange dye (75 min, 82%), respectively. Even at fifth cycle Zn2SnO4 shows 92% efficiency.

Mechanism of formation, characterization and cytotoxicity of green synthesized zinc oxide nanoparticles obtained from Ilex paraguariensis leaves extract

Abstract: Zinc oxide nanoparticles (ZnONPs) was produced using Ilex paraguariensis (mate) leaves extract using a green synthesis process. The influence of ethanolic and aqueous plant extract and zinc source on the green synthesis of ZnONPs was studied. Cyclic voltammetry and Fourier transform infrared spectroscopy (FTIR) were used for the assessment of the mechanism route of ZnONPs while the formation of this nanomaterial was confirmed by X-ray diffraction (XRD) analysis. The morphology and size of the ZnONPs synthesized were evaluated using field emission scanning microscopy (FESEM) and transmission electron microscopy (TEM) analysis. In general, all different synthesized ZnONPs exhibited a hexagonal crystalline structure whereas the size and shape varied depending on the extract and zinc salt used. Nonetheless, the most uniform and smallest ZnONPs were obtained using ethanolic extract and zinc nitrate, showing spherical morphology and a diameter of about 18 nm. With the use of cyclic voltammetry and FTIR analysis, it was concluded that the formation of ZnONPs through green synthesis occurred due to complexation of Zn(II) ions by antioxidants compounds present in the Ilex paraguariensis extract and further thermal degradation of the complexes. Concerning the cytotoxicity assays, the L929 cell viability decreases in a dose-dependent manner for all samples tested. In general, nanoparticles with reduced size and uniform shape exhibited no cytotoxic effects up to a concentration of 10 μ g mL−1. However, higher ZnONPs concentrations caused a decrease in cell viability. This was possibly due an autophagic induction process triggered by the internalization of the nanomaterial. Finally, this work provides a better understanding of the mechanism route to obtain ZnONPs via green method and their potential to be used as a biomedical material.

Morphological effects on the photocatalytic performance of FeVO4 nanocomposite

Abstract: In this study, FeVO 4 nanostructures with different morphologies, nanoparticles, nanorods, nanospheres, nanoplates, and nanoflowers were synthesized at different pH values 2, 4, 7, 10 and 13, respectively. The structural analyses of the samples were done using XRD, SEM, and EDX. Optical studies were performed using FTIR, Raman, UV–Visible, PL and EIS techniques. The chemical analysis, compositions, and bound location were analyzed using X-ray photon spectroscopy (XPS). The surface analyses of all the samples were done using BET. The BET surface area was found 114.97, 20.32, 26.41, 20.28, and 129.20 cm2g − 1 owed to novel morphologies respectively for the nanoparticles, nanorods, nanospheres, nanoplates, and nanoflowers. In photocatalytic decomposition of Congo-Red (CR) organic dye, the FeVO4 nanostructure showed 90 %, 96% degradation efficiency within 50 min under the UV and visible irradiations. The study predicts the effect of the morphology on the photocatalytic activity of the synthesized FeVO 4 nanostructures instead of aspect ratio and surface area. The catalyst retained its reactivity after recycling and exhibited consistent reusability.

Preparation, characterization of Electrospun Polycaprolactone-nano Zinc oxide composite scaffolds for Osteogenic applications

Abstract: Globally bone-grafting procedures are rapidly increasing every year in spite of the limited availability of autografts. Our hypothesis is that the electrospun nanofibers mimic the natural bone for enhanced bone regeneration. Electrospun scaffolds were prepared composed of Polycaprolactone (PCL) alone and PCL-nano Zinc Oxide (nZnO) composite. The nZnO is synthesized by a precipitation method. The scaffold fiber morphology was characterized by scanning electron microscopy (SEM) while its composition by energy dispersive X-ray analysis (EDX), ATR-Fourier transform infrared spectroscopy (ATR-FTIR), powder X-ray diffraction (XRD) and Contact angle (CA) measurement. The scaffolds revealed a nano-porous architecture and incorporation of nZnO in the fibers. The fibers were randomly aligned and increased in diameter in the PCL-nZnO scaffold. Cell culture studies with MG63 cells shows increased proliferation on the PCL-nZnO scaffold. The study reveals that the PCL-nZnO electrospun scaffold provides a nano-porous environment for better cell adhesion and incorporated nZnO particles are osteogenic and can serve as a potential material for bone tissue regeneration.

Effects of poly(vinylpyrrolidone) protected platinum nanoparticles on seed germination and growth performance of Pisum sativum

Abstract: In this article, the effect of poly(vinylpyrrolidone) (PVP) stabilized platinum nanoparticles (Pt:PVP) on seed germination and growth performance of Pisum sativum (Pea) was investigated. Healthy mature Pea seeds were immersed for 1, 2 and 3 h into 1.0 mM concentrated Pt:PVP hydrosol and were sowed into soil. After immersing the seeds for 3 h into this solution, the germination rate decreased by 45% and the dormancy period increased from 2.5 days to 7 days. After 30 days of germination of saplings from seeds treated for 3 h, the root to shoot lengths were 20% less than the saplings from untreated seeds. 1 and 2 h of treatment did not have any significant impact on the germination rate, dormancy and plant growth. Arbuscular mycorrhizal fungi and rhizobial colonization in treated plants significantly decreased with soaking time prolongation. Arbuscular mycorrhizal fungi root colonization was significantly reduced in the plants from 3 h treated seeds group. The yield and biomass content of the produced plants were also calculated. For pea plants from seeds of the 3 h treatment group, the average number of seeds produced per plant increased by 163.5%, but the average seed weight decreased by 66.7%. Comparing with reported observations, it is inferred that either the modification of growth regulatory hormones or biochemicals associated with Pt:PVP during seed germination is responsible for such changes. 3.2 ± 0.8 nm Pt:PVP were prepared by high temperature ethanolic reduction of hexachloroplatinic acid solution containing PVP and were characterized by Transmission Electron Microscopy, X-ray Diffractometry and Ultraviolet–Visible Spectrophotometry.

Influence of annealing temperature on structural, optical and photocatalytic properties of ZnO–TiO2 composites for application in dye removal in water

Abstract: Optimized ratios Zn:Ti (1:1) of ZnO–TiO2 nanocomposites synthesized via the sol–gel method were annealed at; 500 °C, 600 °C, 700 °C, 800 °C and 900 °C. The structural, morphological thermal, optical and chemical changes provoked by thermal treatment at different temperatures were characterized by XRD, SEM/TEM, TGA, DRS and FTIR respectively. The effect of annealing temperature was studied by photocatalytic degradation of methylene blue dye in UV light. XRD revealed mixed phases with high crystallinity whereas SEM images had different particle morphologies for the samples annealed at different temperatures. The photodegradation reported the highest rate for samples annealed at 700 °C which was attributed to the ZnTiO3 phase, increased crystallite growth and reduced band gap with annealing temperatures.

Nanoclay sandwiched reduced graphene oxide filled macroporous polyacrylamide-agar hybrid hydrogel as an adsorbent for dye decontamination

Abstract: Herein, a simple three-step synthesis protocol was adopted to prepare reduced graphene oxide modified nanoclay decorating macroporous polyacrylamide-agar nanocomposite (PAAm-Agar/Clay@r-GO) hydrogel with an objective to treat wastewater Double network structure of PAAm-Agar hybrid hydrogel was formulated through the in situ polymerization approach, followed by cooling at 4 °C, whereas; Clay/GO to Clay/r-GO transformation in hydrogel network was achieved via in situ reduction which also helps to promote macroporosity in hydrogel As-synthesized Clay@GO and PAAm-Agar/Clay@r-GO hydrogel were characterized with XRD, FTIR, SEM, TEM and BET/mercury-porosimetry along with investigating swelling, rheological and thermal behaviors Present study, demonstrated the high dye-adsorption capacity (q exp ∼ 182 mg/g@MB, q exp ∼ 179 mg/g@RhB and q exp ∼ 1103 mg/g@MO at pH ∼ 70) of macroporous PAAm-Agar/Clay@r-GO nanocomposite hydrogel with a faster equilibrium time ( ∼ 5 h@MB/RhB and ∼ 12 h@MO) In basic environment (pH ∼ 10), adsorption capacity is improved to ∼ 189 mg/g and ∼ 1864 mg/g for MB and RhB, respectively The adsorption behavior of PAAm-Agar/Clay@r-GO nanocomposite hydrogel followed the pseudo 2nd order kinetics along with the Langmuir adsorption pattern