Tecnología

ABSTRACT Size controlled cubic Fe3O4 nanoparticles in the size range 90-10 nm were synthesized by varying the ferric ion concentration using the oxidation method. A bimodal size distribution was found without ferric ion concentration and the monodispersity increased with higher concentration. The saturation magnetization decreased from 90 to 62 emu/g when the particle size is reduced to 10 nm. The Fe3O4 nanoparticles with average particle sizes 10 and 90 nm were surface modified with prussian blue. The attachment of prussian blue with Fe3O4 was found to depend on the concentration of HCl and the particle size. The saturation magnetization of prussian blue modified Fe3O4 varied from 10 to 80 emu/g depending on the particle size. The increased tendency for the attachment of prussian blue with smaller particle size was explained based on the surface charge. The prussian blue modified magnetite nanoparticles could be used as a radiotoxin remover in detoxification applications.

ABSTRACT Fe3O4 nanoparticles were surface modified with Prussian blue (PB) and the nanoparticles were used for the removal of cesium (Cs) ion. The attachment of PB with the Fe3O4 and their morphology were explained based on the studies by transmission electron microscope and BET measurements. The Cs ion adsorption studies have shown that the Cs removal efficiency reached maximum within 120 min. The adsorption kinetics studies using Lagergren pseudo-first-order kinetic model suggest the values of the amount of metal ion adsorbed at equilibrium (q e) and adsorption rate constant (k 1) as 22 mg/g and 0.015 min−1, respectively. The capture efficiency of the prepared nanoparticles was studied by varying the flow channel diameter, applied magnetic field, and the fluid flow velocity. The study suggests that PB-Fe3O4 nanoparticles could be used for the detoxification of Cs where the flow velocity is in the range of few tens of cm/s.

Abstract106Ru, 144Ce and 152+154Eu radiotracers sorption experiments (pH: 1–6) have been carried out with polycrystalline columnar/microcrystalline calcite and aragonite obtained from a stalagmite of Dharamjali cave, India. The different domains of the sample were powdered and thoroughly studied using electron microscopic and X-ray spectroscopic techniques. Both 106Ru and 144Ce exhibited higher sorption within calcite varieties compared to aragonite and increased with rising pH, while it showed reverse relation in case of 152+154Eu. Further, it is noted that aragonite offers the highest Kd values for 152+154Eu, whereas 106Ru and 144Ce prefer calcite.

The chemical synthesis of shape and composition controlled Fe based binary alloys has been challenging due to the highly oxidizing nature of Fe. Here, we report the physical properties of flower-like Fe50Co50 nanoparticles prepared by a unique polyol process based on the addition of precursors at the elevated temperature. The magnetic properties are correlated through synchrotron radiation based X-ray diffraction and 57Fe Mossbauer spectrometry. Transmission electron microscopy analysis exposed the flower-like morphology of the FeCo particles. The FeCo nanoparticles showed a coercivity of 440 Oe, attributed to the shape anisotropy of the flower-like shape. Room temperature Mossbauer investigation revealed hyperfine fields of 34.9 and 36.7 T, suggesting two different Fe environments in the disordered state. Mossbauer analysis also showed the presence of superparamagnetic Fe-oxide with a relative fraction of 17%.

Fast recombination of photoinduced charge carriers is a major problem in the case of semiconductor based photocatalysts, which must be solved for their potential application in photocatalysis. In this work, photostable CdS QDs/BiOI composites have been successfully fabricated by a two-step precipitation–deposition method. The prepared samples were characterized by X-ray diffraction (XRD), UV–vis diffuse reflection spectroscopy (UV–vis DRS), photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Mott–Schottky, and electrochemical impedance analysis. The potential applications of CdS QDs/BiOI composite materials have been tested toward decolorization of rhodamine B (RhB) solution and hydrogen generation under solar light and visible light irradiation, respectively. It has been observed that hydroxyl radicals, electrons, and holes played a major role in decolorization of RhB solution. Among all prepared photocatalysts, 4% CdS QDs/BiOI composite wa...

To investigate molecular aspects of the antibacterial effect of size-dependent core-shell intrinsic defects of nanocrystalline ZnO synthesized through high energy ball milling technique. Mechanically synthesized and characterized 7, 10 and 15 h milled ZnO nanoparticles were evaluated for antibacterial activity with molecular investigation by computational molecular docking. Synthesized ZnO nanoparticles displayed shrinkage of core and increase of shell with reduction in size of bulk ZnO particles from 250 to 80, 40 and 20 nm and increase in zeta potential up to -19 mV in 7, 10 and 15 h nano ZnO. Antibacterial activity was found increased with decrease in size due to increased reactive oxygen species and membrane damage in bacteria. Synthesized nano ZnO exhibit size-dependent antibacterial action as consequences of interactions with cell membrane proteins via hydrogen bond interaction with amino acid residues followed by internalization, membrane depolarization and induction of react...

In this study, rapid one step facile synthesis of silver nanoparticles (AgNPs) was done using culture supernatant of two Gram positive (B. thuringiensis and S. aureus) and Gram negative (E. coli and Salmonella typhimurium [STAgNP]) bacterial strains and were termed as "Bacillus thuringiensis," "Staphylococcus aureus," "Escherichia coli," and "STAgNP," respectively. Synthesized AgNPs were well characterized with the help of different standard techniques like FESEM, DLS, UV-Vis spectroscopy, and Fourier transform infrared. Mechanism of AgNPs synthesis was elucidated using in silico approach. In vivo cytotoxicity of synthesized AgNPs was assessed in embryonic Zebrafish model with the help of uptake, oxidative stress, and apoptosis induction experimental assays, and the mechanism was investigated through in silico approach at the molecular level. The result showed successful biosynthesis of 20-40 nm sized AgNPs stable with zeta potential of - 45 t...

Implication of gold nanoparticles in industrial and day-to-day life products at extensive scale has raised concern about their toxicity to environment and human health. Moreover, quest of new technologies for production of biocompatible nanoparticles increased. This study explores the molecular toxicology of AuNP with enlightenment of their green synthesis using medicinal plant extract as reducing and stabilizing agent. Synthesized CAuNP were characterized for their physiochemical properties by standard techniques like FESEM, TEM, DLS, UV-Vis spectroscopy and FTIR. GCMS analysis revealed the involvement of -OH compounds for CAuNP synthesis. Determined size and zeta potential of CAuNP was found to be 21 ± 08 nm and -24 ± 11 mV with SPR peak at 554 nm. LC50 of CAuNP with zebrafish embryos was 69 ± 12 µg/ml compared to 52 ± 06 µg/ml of AuNP. Gold nanoparticles were found to exhibit concentration dependent morphological abnormalities with acute effect at cellular and molecular level. Ex...

Abstract LaMnO3 perovskite oxide has got tremendous attraction in electrochemical field owing to their favourable physical and chemical properties. However, aggregated and distorted morphology of regular perovskites that are prepared at higher temperatures (>500 °C) led to lesser active sites provided to enable the electrochemical reaction. Here we propose a green synthetic approach to overcome these deficiencies and to obtain better electrochemical performance. 3D polyhedron structured LaMnO3 nanoparticles are synthesized using natural lemon juice (LJ) as a green surfactant. The aggregation of these particles is removed and a well separated individual particle has been formed. This well defined polyhedron structured LMO nanoparticle possessed a 3 fold enhancement in its specific capacitance. A symmetric two electrode cell system has also been fabricated to investigate the real life application of LMO as a supercapacitor. The electrode in this symmetric cell configuration could deliver a maximum energy density of 52.5 Wh kg−1 at a power density of 1000 W kg−1. This is an outstanding result among aqueous electrolyte symmetric supercapacitors. Moreover, the room temperature fluctuation effect on the specific capacitance of LMO cell has also been investigated. This LJ assisted synthesize of LMO perovskite presented here enlighten a simple paradigm for fabricating high energy electrochemical storage devices.

Mucoadhesive type ocular film has been prepared for studying the anti-inflammatory potential of amlodipine (AML) on carrageenan-induced rabbit model and the effect of sulphobutyl-ether-beta-cyclodextrin on corneal permeation was tested. Hydroxypropyl methylcellulose (HPMC) ocular film was prepared after complexation of amlodipine with β-cyclodextrin, (BCD), hydroxypropyl β-cyclodextrin (HPCD), and sulfobutylether β-cyclodextrin (SBCD). The film without cyclodextrin showed a maximum swelling, and erosion to the highest extent. Both drug release and permeation were highly diffusion controlled and highest improvement was observed with SBCD due to increased dissolution, compared to other formulations with or without cyclodextrin. Highest binding energy and highest extent of amorphization were noticed in the SBCD film formulation. Improved amlodipine release in-vitro and ocular permeation were found by the HPMC film formulation after complexation of the drug with cyclodextrins wherein SBCD exhibited both to the highest extent. Binary and ternary systems molecular docking studies confirmed the lowest energy of binding between amlodipine and BCD compared to HBCD and SBCD. Signs of acute inflammation were mitigated within 2 h of film application in the cul-de-sac. Presence of sulphobutyl-ether β-cyclodextrin in the amlodipine-HPMC film can improve ocular permeation significantly and could be utilized as mucoadhesive type formulation for anti-inflammatory activity.

Cu doped ZnO nanoparticles abbreviated as Zn1−xCuxO (x = 0, 0.01 and 0.03) were synthesized by mechanical alloying. The change in structure, morphology, band gap and dielectric properties of the synthesized nanoparticles were investigated by XRD, FE-SEM, FTIR, UV–Vis and impedance analyzer respectively. The incorporation of the dopant Cu into ZnO hexagonal wurtzite structure has been verified by X-ray diffraction (XRD) and the Cu doping on the structural bonding of ZnO has been verified by fourier transformation infrared spectra (FTIR).The XRD spectra shows that all the synthesized nanoparticles are single phase, hexagonal wurtzite structure and belong to the space group of P63mc.Crystallite size of Cu doped ZnO (15 nm) nanoparticles is smaller than pure ZnO (18 nm) and peak broadening exists in the system. FE-SEM analysis indicates that Cu doping affects the surface morphology of ZnO. The band gap (Eg) of ZnO decreases with Cu doping which can be attributed to sp-d exchange interaction between the ZnO band electrons and localized d electrons of Cu2+ ions. The dielectric constant of ZnO decreases with Cu doping.