Structure Properties Of Nanoparticles Research Articles

Tagetes erecta-Mediated Biosynthesis of Mn3O4 Nanoparticles: Structural, Electrochemical, and Biological Investigations.

Mn3O4 nanoparticles (NPs) find diverse applications in the fields of medicine, biomedicine, biosensors, water treatment and purification, electronics, electrochemistry, and photoelectronics. The production of Mn3O4 NPs was reported earlier through various physical, chemical, and green routes, but no studies have still been performed on their biosynthesis from Tagetes erecta. We synthesized manganese oxide NPs, i.e., (Mn3O4)L and (Mn3O4)P NPs, by utilizing leaves and petals, respectively, of T. erecta as reducing and stabilizing agents. The investigated green path is eco-friendly and does not involve any hazardous raw materials. The structural properties of NPs were determined by X-ray diffraction (XRD) analysis, spectroscopies (Fourier transform infrared (FTIR), Raman, and UV-visible), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The NPs were also evaluated for their electrochemical properties by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD). XRD analysis was performed to verify their tetragonal geometry, and the crystallite size (19.24 nm) of (Mn3O4)P was smaller than that (20.84 nm) of (Mn3O4)L NPs. SEM images displayed a porous and spherical morphology with a diameter of 14-35 nm. FTIR spectra of (Mn3O4)L and (Mn3O4)P displayed Mn-O vibrations at 605.69 and 616.87 cm-1, respectively, and the hydrous nature of the material. Raman spectroscopy revealed the existence of tetrahedral and octahedral units along with A1g, T2g, and Eg active modes of Mn3O4 and 2TO mode. UV-visible analyses of (Mn3O4)L and (Mn3O4)P NPs showed absorption peaks at 272.3 and 268.8 nm, along with band gaps of 4.83 and 5.49 eV, respectively. TGA curves displayed good thermal stabilities up to 600 °C and a loss of moisture content. DSC curves exhibited exothermic/endothermic peaks with glass transition temperatures of 258.9 and 308.7 °C for (Mn3O4)P and (Mn3O4)L, respectively. The CV curves showed redox peaks and confirmed that the electrochemical reaction takes place in the Mn3O4 material. GCD scans revealed the capacitive behavior of NPs and their suitability as electrodes in energy storage devices. However, (Mn3O4)L will act as a good material for energy storage applications as compared to (Mn3O4)P NPs. The synthesized NPs were also tested for their antibacterial efficacy by biofilm inhibition and agar well diffusion methods. The NPs showed higher activities against Staphylococcus aureus (Gram-positive) than against Escherichia coli (Gram-negative), and (Mn3O4)P was more bioactive than (Mn3O4)L.

Preparation of high stable nanofluid based N-doped quantum dot in diethanolamine solution for carbon dioxide absorption

According to the increase of greenhouse gases such as CO2 in the atmosphere following the growth and establishment of various industries, serious and rapid solutions for this challenge are required to prevent the release of this gas. CO2 absorption in amine nanofluid is an emerging method nowadays. In this study, chitosan was synthesized from shrimp shells to prepare carbon dots (CDs). These CDs were treated by amino groups using the hydrothermal method. The structural properties of nanoparticles (NPs) were characterized by FT-IR, XRD, SEM, and zeta potential analyses and the NPs were quasi-spherical with regular micropores. The efficiency of CO2 absorption from a gas mixture of CO2/N2 was considered as a percentage of the difference in CO2 absorption capacities between nanofluid and diethanolamine (DEA, 10 wt%) solution compared to the CO2 absorption capacity of DEA. The experimental results showed that the efficiency of CO2 absorption for CDCH:N-200-8, CDCH:N-180-12, CDCH:N-200-12 and CDCH:N-180-8 nanofluids was equal to 73.86, 53.87, 49.25 and 22.88 %, respectively, which had increased CO2 absorption significantly compared to the DEA base fluid. Among the synthesized samples, CDCH:N-200-8 nanofluid was a unique candidate for CO2 capture from the atmosphere due to its high absorption efficiency since these particles had advantages such as ease of use, no corrosion, no deposition in the process, chemical inertness and high thermal stability.

Defect related photocatalytic and photoluminescent characteristics of Gd-doped SnO2 nanoparticles with different shapes

A new method for the preparation of Gd-doped SnO2 nanoparticles based on the precipitation method followed by hydrothermal treatment has been developed. Two different shape series of nanoparticles with different Gd content were obtained and fully characterized. Wide number of parameters, including lattice parameters, crystallite size, particle size, surface composition, oxygen vacancies, structural defects, band gap energy, luminescent spectra, band structure and density of states were determined.It was shown that the mechanism of oriented attachment of nanoparticle growth is stimulated during hydrothermal treatment. Quantum computer calculations of the interaction energies of oriented nanoparticles were performed and the role of ions in the reaction media was revealed.A study of the photoluminescence of the obtained nanoparticles was carried out, showing a blue photoluminescence corresponding to the oxygen vacancies, indicating their presence.Photocatalytic activity of nanoparticles when irradiated with visible light was shown, which is explained by quantum chemical calculations and demonstrated in the example of a colored solution of the organic dye methylene blue. The relation between the morphological and structural properties of nanoparticles and their photocatalytic properties has been studied in detail. A high degradation percentage is achieved using a regular commercially available LED lamp with a visible light spectrum.Novelty of the work lies in obtaining series of samples with various parameters, detailed studies of oriented attachment mechanism and impact of the nanoparticle parameters on photocatalytic properties. A concept for the development of efficient photocatalysts based on chemical and computational experiments is proposed.

Prediction of cytotoxicity of heavy metals adsorbed on nano-TiO2 with periodic table descriptors using machine learning approaches.

Nanoparticles with their unique features have attracted researchers over the past decades. Heavy metals, upon release and emission, may interact with different environmental components, which may lead to co-exposure to living organisms. Nanoscale titanium dioxide (nano-TiO2) can adsorb heavy metals. The current idea is that nanoparticles (NPs) may act as carriers and facilitate the entry of heavy metals into organisms. Thus, the present study reports nanoscale quantitative structure-activity relationship (nano-QSAR) models, which are based on an ensemble learning approach, for predicting the cytotoxicity of heavy metals adsorbed on nano-TiO2 to human renal cortex proximal tubule epithelial (HK-2) cells. The ensemble learning approach implements gradient boosting and bagging algorithms; that is, random forest, AdaBoost, Gradient Boost, and Extreme Gradient Boost were constructed and utilized to establish statistically significant relationships between the structural properties of NPs and the cause of cytotoxicity. To demonstrate the predictive ability of the developed nano-QSAR models, simple periodic table descriptors requiring low computational resources were utilized. The nano-QSAR models generated good R2 values (0.99-0.89), Q2 values (0.64-0.77), and Q2F1 values (0.99-0.71). Thus, the present work manifests that ML in conjunction with periodic table descriptors can be used to explore the features and predict unknown compounds with similar properties.

Multifunctional Tb-doped SnO2 based photocatalytic agent for water remediation: Study of defect-related properties

A new methodology to obtain Tb-doped SnO2 nanoparticles based on precipitation method followed by hydrothermal treatment was developed. Two series of nanoparticles with various Tb concentrations were fully characterized with large number of methods, including XRD method, FTIR, XPS, and Raman spectroscopy, TEM imaging, SSA estimation, optical transmittance study, luminescence spectroscopy and quantum-chemical calculations.The oriented attachment mechanism of nanoparticle growth is shown to occur under hydrothermal treatment. Computational study of interaction energies of mutually oriented nanoparticles and role of ions in the synthesis media was performed. Study of photoluminescence characteristics of the obtained nanoparticles is provided. The presence of blue and green luminescence is shown. The blue luminescence is related to SnO2 self-luminescence, while the green is related to Tb. Increase of Tb concentration suppress blue self-luminescence of SnO2, and promote green luminescence due to an increase of the energy transfer from crystal host to doping Tb ions.The nanoparticles are shown to possess photocatalytic activity of 97–100% under Vis light irradiation. Using a complex of modern physicochemical methods, a new factor affecting photocatalytic efficiency was revealed – the ratio of vacancies to defects (Vac/Def). A clear dependency of photocatalysis and normalized Vac/Def ratio to interaction energy between pollutant and catalysts surface is explained via quantum-chemical calculations for the first time, and demonstrated on examples of colored solution of organic dye methylene blue and colorless solution of oxytetracycline. Detailed study of the relation between morphological and structural properties of nanoparticles and their photocatalytic properties is provided. High degradations percent are achieved under simple LED light bulb. A concept of a chemical and computational experiments-based route for the development of effective photocatalysts is suggested.

Amoxicillin Degradation and Antimutagenic Potential of Phytofabricated Silver Nanoparticles-Doped Polyurethane Membrane for Wastewater Treatment

Human encroachment and rapid usage of antibiotics, and toxic chemicals have given rise to fatal waterborne diseases and drinking water crises. This work focuses on the phytofabrication of silver nanoparticle-doped polyurethane membranes (PUM) for wastewater treatment via amoxicillin degradation and its antimutagenic potential. Fresh leaf extracts of Acokanthera oppositifolia and Leucaena leucocephala were utilized for the reduction and capping of silver ions. The structural properties of nanoparticles were studied using scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive analysis (EDAX), and Fourier transform infrared spectroscopy (FTIR). The ability of a polyurethane membrane embedded with silver nanoparticles to remove amoxicillin and residual antimicrobial in treated water was also tested. Additionally, antimutagenic activity against Salmonella typhimurium strains (TA 98 and 100) with 2-aminofluorene and sodium azide mutagens was investigated in filtered water. The effectiveness of the developed membrane was assessed in a sewage sample using the catalase test and plating on an agar plate to estimate the reduction in the microbial population. The finding reveals that the membranes doped with nanoparticles of Leucaena leucocephala demonstrated the highest amoxicillin degradation (94%) and antimutagenic (99.0%) with pseudo-first-order kinetics [Formula: see text] of 0.96. The microbial population was reduced from [Formula: see text] to [Formula: see text] and [Formula: see text] CFU/mL after filtration by PUM-doped nanoparticles of Acokanthera oppositifolia and Leucaena leucocephala, respectively. The results conclude that polyurethane membranes doped with silver nanoparticles are very effective in wastewater treatment and hold great promise for wastewater remediation applications.

Influence of Ligands on Physicochemical Characteristics of Magnetic Nanoparticles

Magnetic-bead separation or purification serves as a technique for effective isolation of biomolecules. In presented work we prepared and characterized core-shell magnetic nanoparticle samples consisted of Fe 3 O 4 core coated with SiO 2 shell. Samples were subsequently coated with ligands MPTMS (3-(mercaptopropyl)trimethoxysilane), CPTMS (3-(chloropropyl)trimethoxysilane) and MMSP (3-(trimethoxysilyl)propyl methacrylate) with aim to increase the number of active centers for specific binding with RNA. Such samples were further investigated for their magnetic properties, size, and morphology. Magnetic properties were studied in DC field up to 5 T in temperature range 5 – 300 K. Size and morphology were determined from SEM micrographs and elemental compositions of the samples were investigated using EDX analysis. Modification of nanoparticle surface with different ligands leads to modification of active centers on the SiO 2 surface on which the DNA and RNA molecules can be bounded. It also causes the change in magnetic and structural properties of nanoparticles.

The influence of γ-irradiation on molecular structure and mass attenuation coefficients of γ-Al2O3 nanoparticles

In this research, γ-Al2O3 nanoparticles (NPs) were synthesized by using the sol–gel process. The photon attenuation properties of these NPs were obtained by measuring the linear and mass attenuation coefficients (μl, μm) at different photon energies. In addition, the theoretical values of μm for γ-Al2O3 micro-particles were calculated using the WinXCom computer program and compared with the experimental values of μm for NPs of γ-Al2O3. Furthermore, in order to evaluate the impact of γ-irradiation on these NPs, the experimental values of μl and μm for γ-Al2O3 NPs, before and after receiving 20 kGy dose of γ-irradiation, were investigated. It was observed that μm of γ-Al2O3 NPs decreases after receiving γ-irradiation because of increasing the photon’s energy, which indicates the changes in the molecular structure of NPs after γ-irradiation. Moreover, the structural properties of NPs were evaluated by UV–Vis spectroscopy, x-ray diffraction patterns, and scanning electron microscopy images. UV–Vis spectroscopy showed an absorption peak at 212.5 nm before γ-irradiation, and the absorption peak of NPs disappeared when γ-irradiation was started. The average crystalline size was determined to be 3.65 nm in the sample before γ-irradiation and 9.29 nm in the sample with the maximum dose of 20 kGy. The results of scanning electron microscopy show an increase in particle size from 6.5 nm in a non-irradiated sample up to 9 nm in a sample with the highest γ-irradiation dose.

Recent Advances in the Gastrointestinal Fate of Organic and Inorganic Nanoparticles in Foods.

Inorganic or organic nanoparticles are often incorporated into foods to enhance their quality, stability, nutrition, or safety. When they pass through the gastrointestinal environment, the properties of these nanoparticles are altered, which impacts their biological effects and potential toxicity. Consequently, there is a need to understand how different kinds of nanoparticles behave within the gastrointestinal tract. In this article, the current understanding of the gastrointestinal fate of nanoparticles in foods is reviewed. Initially, the fundamental physicochemical and structural properties of nanoparticles are discussed, including their compositions, sizes, shapes, and surface chemistries. Then, the impact of food matrix effects and gastrointestinal environments on the fate of ingested nanoparticles is discussed. In particular, the influence of nanoparticle properties on food digestion and nutraceutical bioavailability is highlighted. Finally, future research directions are highlighted that will enable the successful utilization of nanotechnology in foods while also ensuring they are safe.

The Impact of Multiple Functional Layers in the Structure of Magnetic Nanoparticles and Their Influence on Albumin Interaction.

In nanomedicine, hybrid nanomaterials stand out for providing new insights in both the diagnosis and treatment of several diseases. Once administered, engineered nanoparticles (NPs) interact with biological molecules, and the nature of this interaction might directly interfere with the biological fate and action of the NPs. In this work, we synthesized a hybrid magnetic nanostructure, with antibacterial and antitumoral potential applications, composed of a magnetite core covered by silver NPs, and coated with a modified chitosan polymer. As magnetite NPs readily oxidize to maghemite, we investigated the structural properties of the NPs after addition of the two successive layers using Mössbauer spectroscopy. Then, the structural characteristics of the NPs were correlated to their interaction with albumin, the major blood protein, to evidence the consequences of its binding on NP properties and protein retention. Thermodynamic parameters of the NPs–albumin interaction were determined. We observed that the more stable NPs (coated with modified chitosan) present a lower affinity for albumin in comparison to pure magnetite and magnetite/silver hybrid NPs. Surface properties were key players at the NP–biological interface. To the best of our knowledge, this is the first study that demonstrates a correlation between the structural properties of complex hybrid NPs and their interaction with albumin.

Enhancing Inflammation Targeting Using Tunable Leukocyte-Based Biomimetic Nanoparticles.

Biomimetic nanoparticles aim to effectively emulate the behavior of either cells or exosomes. Leukocyte-based biomimetic nanoparticles, for instance, incorporate cell membrane proteins to transfer the natural tropism of leukocytes to the final delivery platform. However, tuning the protein integration can affect the in vivo behavior of these nanoparticles and alter their efficacy. Here we show that, while increasing the protein:lipid ratio to a maximum of 1:20 (w/w) maintained the nanoparticle’s structural properties, increasing protein content resulted in improved targeting of inflamed endothelium in two different animal models. Our combined use of a microfluidic, bottom-up approach and tuning of a key synthesis parameter enabled the synthesis of reproducible, enhanced biomimetic nanoparticles that have the potential to improve the treatment of inflammatory-based conditions through targeted nanodelivery.

Free energy for inclusion of nanoparticles in solvated polymer brushes from molecular dynamics simulations.

The inclusion of nanoparticles (NPs) into solvated polymer brushes (PBs) provides a path for designing novel nanocomposites and a multifunctional surface for wide applications. Despite intensive study over the years, the correlation between the structural properties of NPs (or PBs) and the NP-PB interactions is still to be well unveiled. Here, we present molecular dynamics simulations with the umbrella sampling method to systematically investigate the interaction between NPs and PBs, via calculating the free energy cost (Uins, associated with the inclusion of NPs into PBs) as a function of a series of factors, such as brush grafting density (ρg), grafted polymer chain architecture, NPs' size, NPs' surface properties, and NPs' shape and surface structure, as well as the solvent quality. Our results show that at a fixed NP size, the inclusion free energy approximately scales with the osmotic pressure (Π) of PBs under good solvent conditions [Uins∼Π(ρg)∼ρg 3/2], regardless of the NPs' shape and surface properties. Once the radius of the NP (RNP) is varied, a scaling law, Uins∼RNP 3, can be obtained for NPs deeply inserted in swollen PBs with a high grafting density. While for shallow inclusions, a surface tension correction of the form ∼RNP 2 plays a role. Further studies reveal that Θ and poor solvents will weaken the osmotic pressure effects of PBs and reversely enhance the surface tension effects due to the increased NP-brush repulsion. Our simulation results verify previous theoretical perspectives that the Uins can be approximated by the sum of the volume and surface contributions from the osmotic pressure Π and surface tension γ (Uins∼ΠRNP 3+γRNP 2). Our work not only helps us to understand the applicability of previous theories on the NP-PB system but also reveals the key factors that impact the NP-PB interaction in a series of probable conditions, which may provide valuable guidelines for designing and engineering novel nanomaterials based on functional NPs and PBs.

Naturally-occurring cholesterol analogues in lipid nanoparticles induce polymorphic shape and enhance intracellular delivery of mRNA

Endosomal sequestration of lipid-based nanoparticles (LNPs) remains a formidable barrier to delivery. Herein, structure-activity analysis of cholesterol analogues reveals that incorporation of C-24 alkyl phytosterols into LNPs (eLNPs) enhances gene transfection and the length of alkyl tail, flexibility of sterol ring and polarity due to -OH group is required to maintain high transfection. Cryo-TEM displays a polyhedral shape for eLNPs compared to spherical LNPs, while x-ray scattering shows little disparity in internal structure. eLNPs exhibit higher cellular uptake and retention, potentially leading to a steady release from the endosomes over time. 3D single-particle tracking shows enhanced intracellular diffusivity of eLNPs relative to LNPs, suggesting eLNP traffic to productive pathways for escape. Our findings show the importance of cholesterol in subcellular transport of LNPs carrying mRNA and emphasize the need for greater insights into surface composition and structural properties of nanoparticles, and their subcellular interactions which enable designs to improve endosomal escape.

One-Pot Synthesis of Lithium Nickel Manganese Oxide-Carbon Composite Nanoparticles by a Flame Spray Pyrolysis Process

The nanoparticles based on nickel-manganese oxide and carbon-coated LiNi0.5Mn1.5O4 are synthesized by flame spray pyrolysis technology with controlled particle sizes. The structural properties of nanoparticles are characterized by X-ray diffraction and high-resolution electron microscopy. It is observed that the higher surface tension of precursors in the flame spray pyrolysis setup increases the particle sizes. The post annealing treatment significantly enhances the crystallinity of nanoparticles due to the favorable oxidation process and the structure conversion from NiMn2O4 to NiMnO3. In addition, the solid-state reaction of as-prepared NiMn2O4 results in the LiNi0.5Mn1.5O4 nanoparticles which can be applied to the cathode in Li-ion batteries. The carboncoated LiNi0.5Mn1.5O4 nanoparticles are also made by additional carbonization reaction. The control of surface tension of precursors in the flame spray pyrolysis process is expected to result in the small size of nanoparticles, which can result in high cyclic stability and high capacity for Li-ion batteries.

Effects of Annealing Temperature on Phase Transformation of CoTiO3 Nanoparticles and on their Structural, Optical, and Magnetic Properties

Cobalt titanate (CoTiO3) nanoparticles have been prepared by annealing of precursor molecules obtained from a mixture of titanium isopropoxide with cobalt nitrate and glacial acetic acid by sol-gel method. The structural properties of nanoparticles were investigated by X-ray diffraction (XRD) and Raman spectroscopy to determine the phase composition and crystallite size. The optical properties of the nanoparticles were characterized by UV-Vis absorption spectra. XRD and Raman analysis confirmed that CoTiO3 phase was present at annealing temperatures above 700 °C. For the investigation of the elemental compositions and chemical binding configurations, the samples were analyzed by X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the morphology and particle sizes and were found to be between 70 and 90 nm. The samples annealed at temperatures equal or higher than 600 °C exhibited paramagnetic behavior, whereas those annealed at or above 700 °C exhibited superparamagnetic behavior as shown by vibrating sample magnetometer at room temperature.

A Simulation Study on the Interaction Between Pollutant Nanoparticles and the Pulmonary Surfactant Monolayer.

A good understanding of the mechanism of interaction between inhaled pollutant nanoparticles (NPs) and the pulmonary surfactant monolayer is useful to study the impact of fine particulate matter on human health. In this work, we established coarse-grained models of four representative NPs with different hydrophilicity properties in the air (i.e., CaSO4, C, SiO2, and C6H14O2 NPs) and the pulmonary surfactant monolayer. Molecular dynamic simulations of the interaction during exhalation and inhalation breathing states were performed. The effects of NP hydrophilicity levels, NP structural properties, and cholesterol content in the monolayer on the behaviors of NP embedment or the transmembrane were analyzed by calculating the changes in potential energy, NP displacement, monolayer orderliness, and surface tension. Results showed that NPs can inhibit the ability of the monolayer to adjust surface tension. For all breathing states, the hydrophobic C NP cannot translocate across the monolayer and had the greatest influence on the structural properties of the monolayer, whereas the strongly hydrophilic SiO2 and C6H14O2 NPs can cross the monolayer with little impact. The semi-hydrophilic CaSO4 NP can penetrate the monolayer only during the inhalation breathing state. The hydrophilic flaky NP shows the best penetration ability, followed by the rod-shaped NP and spherical NP in turn. An increase in cholesterol content of the monolayer led to improved orderliness and decreased fluidity of the membrane system due to enhanced intermolecular forces. Consequently, difficulty in crossing the monolayer increased for the NPs.

Lithium Nickel Manganese Oxide-Carbon Composite Nanoparticles Synthesized By a Flame Spray Pyrolysis Process

The nanoparticles based on either nickel-manganese oxide or carbon-coated LiNi0.5Mn1.5O4 are synthesized by flame spray pyrolysis technology with controlled particle sizes. The structural properties of nanoparticles are characterized by x-ray diffraction and high resolution electron microscopy. It is observed that the higher surface tension of precursors in the flame spray pyrolysis setup increases the particle sizes. The post annealing treatment significantly enhances the crystallinity of nanoparticles due to the favorable oxidation process and the structure conversion from NiMn2O4 to NiMnO3. In addition, the solid state reaction of as-prepared NiMn2O4 results in the LiNi0.5Mn1.5O4 nanoparticles which can be applied to cathode materials in Li-Ion batteries. The carbon-coated LiNi0.5Mn1.5O4 nanoparticles are also made by additional carbonization reaction. The control of surface tension of precursors in the flame spray pyrolysis process is expected to result in the small size of nanoparticles for cathode materials in high cyclic stability and high capacity Li-ion batteries.

Fungal strain impacts the shape, bioactivity and multifunctional properties of green synthesized zinc oxide nanoparticles

Abstract This work aimed to investigate the influence of fungal strains onto shape, functional properties, and potential applications of biosynthesized nanoparticles (NPs). The aqueous extract of two newly isolated fungal strains, Fusarium keratoplasticum strain (A1-3) and Aspergillus niger strain (G3-1), were used for synthesis of ZnO-NPs. Nanoparticles formation was confirmed by visual observation of color change and UV–visible spectroscopy. The morphological and structural properties of NPs were analyzed by Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), Dynamic Light Scattering (DLS) and zeta potential analyses. Different ZnO-NPs shapes were obtained; where, F. keratoplasticum strain (A1-3) synthesized hexagonal NPs and A. niger strain (G3-1) synthesized nano-rod shape NPs. The antibacterial activities against Gram-negative and Gram-positive bacteria as well as in vitro cytotoxicity against three different animal cell lines exhibited that biocidal activity of NPs is a shape-dependent. Furthermore, nanoparticle shapes greatly affected the multifunctional properties of textile fabrics coated with ZnO-NPs. Nano-rod NPs showed enhanced antibacterial properties against pathogenic bacteria and UV-protection index compared to the hexagonal ZnO-NPs. Therefore, this work provides a gateway to explore shape-dependent properties of biologically synthesized NPs and their potentiality to be utilized for specific applications.

Lead Remediation Using Smart Materials. A Review

Abstract The nanoparticles have been prepared and employed as excellent adsorbents for the sequestration of heavy metal ions and hazardous impurities from the aqueous media. The surface morphological, textural and structural properties of nanoparticles have been modified, which are capable and potentially useful for the remediation of metal ions. Several metals (oxides, doped, nanocomposites of Fe, Ti, Zn, SiO2, SiC, Mo, Co, Ni, Zr, Mn, Si, S, Al, Cu, Ce, graphene, CNTs) were reported an efficient adsorbents for the removal of lead (Pb) ions from aqueous media and polluted water. The present review focuses on different kinds of nanoparticles such as metal oxides, carbon based and host supported employed for removal of Pb ions under varying experimental conditions such as pH, temperature, contact time and concentrations. The preparation strategies, physicochemical properties and adsorption are also discussed. Based on studies, it was found that the smart materials are affective adsorbents for the purification of wastewater containing Pb ions and could possibly extended for the remediation of other heavy metal ions.

Magnetic properties of NaY1−x−yHoxYby(WO4)2: x = 0.05, y = 0.02 and KY1−x−yHoxYby(WO4)2: x = 0.02, y = 0.01 nanopowders obtained by Pechini and hydrothermal methods

Potassium- and sodium-yttrium double tungstate nanopowders co-doped with Yb3+, Ho3+ ions were investigated for their magnetic properties for the first time. We performed the analysis of the compounds using two methods: Electron Paramagnetic Resonance (EPR) and static Magnetic Susceptibility (MS). We have described the symmetry of doped ions environment and corresponding magnetic, optical and structural properties of the above compounds obtained by hydrothermal and Pechini methods. It was performed for the compounds underwent to different calcination temperatures in the range from 600 °C to 800 °C. For potassium and sodium double tungstates the local symmetry of ytterbium ions is found to be C2 and does not change with the calcination temperature rise. Based on the finite-size effect we determined the relative size of the nanoparticles agglomeration, observing changes in the values of Curie-Weiss temperature and the intensity of the EPR signal for various calcination temperatures. The magnetic and structural properties of nanoparticles were compared to corresponding ones registered for single crystals and crystalline powders obtained using other methods.