Pure AgNO3 Research Articles

A study on the synthesis and characterization of Schiff base stabilized silver nanoparticles against propionic bacteria

Bacteriological contamination removing one of the most conservational problem in various environmental areas, predominantly in biomedical, effect of health care and disinfected applications. As synthesized optically transparent Schiff base stabilized silver nanoparticles (L-1AgNPs) of Schiff base ligand (N-(diphenylmethylene)-6-nitrobenzo[d]thiazol-2-amine) (L-1), has been successfully prepared, Schiff base stabilized silver nanoparticles were synthesized by easy process and straight forward protocol and using co-precipitation method. The synthesis of Schiff base stabilized silver nanoparticles using Schiff base ligand as a stabilizer. The synthesized Schiff base ligand (L-1) and its stabilized silver nanoparticles characterized were various spectroscopic technique, such as Fourier transform infrared (FT-IR), 1H NMR, Electron Spray Ionization (ESI) Mass, and UV–Visible spectroscopy, P-XRD and Transmission Electron Microscopy (TEM). AgNPs using as shows antibacterial activities of pathogenic gram positive bacteria like Propionic bacteria by using disc diffusion method. Here disc diffusion methods used for comparative studies and found inhibition zone on culture plate. The antimicrobial enhancing efficiency for Ag-nanopartics and diminished the pathogenic behaviour as conservational problem. Here comparatively L-1 is less antimicrobial activity with comparatively L-1-AgNPs showing 14 mm zone of inhibition effect. There is no inhibition zone of pure AgNO3. The microorganism for Propionic Bacteria against L-1-AgNPs show good activity as compared to L-1 and AgNO3.

Catalytic selective recovery of silver from dilute aqueous solutions and e-waste leachates

The two-step catalytic process is proposed for the recovery of silver ions from aqueous solutions. First, the Ag+-containing solution is enriched with hydrogen gas and recirculated through the Pt-loaded activated carbon (Pt/AC). The Ag+ ions are reduced into the metal particles at ambient temperature and H2 gauge pressure of 1 atmosphere. Next, the Ag particles precipitated on the Pt/AC are oxidized by air to form the pure Ag+ concentrate and to regenerate the catalyst. The process was studied using pure AgNO3 solutions at varied pH values (0.0, 1.5 and 3.9) in a batch mode system that was operated with Pt/AC particles loaded with 0.1–1.0% of Pt metal. The complete removal of Ag+ ions was achieved within<2 h of hydrogenation of 1-liter AgNO3 solutions with an initial concentrations of 100–1000 mgAg/L. The hydrogenation rate was not influenced by the pH value. Increasing the Pt load in the Pt/AC media above 0.25% did not result in an increase in the Ag+ hydrogenation rate. Next, the process was applied for the separation of Ag+ ions from H2SO4 leachates of Ag2O-Zn batteries. Finally, it was shown that due to a large difference in standard reduction potentials the silver and the copper ions can be “kinetically” separated within the hydrogenation and the oxygenation steps of the process.

Increased Antibacterial and Antibiofilm Properties of Silver Nanoparticles Using Silver Fluoride as Precursor

Silver nanoparticles were produced with AgF as the starting Ag(I) salt, with pectin as the reductant and protecting agent. While the obtained nanoparticles (pAgNP-F) have the same dimensional and physicochemical properties as those already described by us and obtained from AgNO3 and pectin (pAgNP-N), the silver nanoparticles from AgF display an increased antibacterial activity against E. coli PHL628 and Staphylococcus epidermidis RP62A (S. epidermidis RP62A), both as planktonic strains and as their biofilms with respect to pAgNP-N. In particular, a comparison of the antimicrobial and antibiofilm action of pAgNP-F has been carried out with pAgNP-N, pAgNP-N and added NaF, pure AgNO3, pure AgF, AgNO3 and added NaF and pure NaNO3 and NaF salts. By also measuring the concentration of the Ag+ cation released by pAgNP-F and pAgNP-N, we were able to unravel the separate contributions of each potential antibacterial agent, observing an evident synergy between p-AgNP and the F− anion: the F− anion increases the antibacterial power of the p-AgNP solutions even when F− is just 10 µM, a concentration at which F− alone (i.e., as its Na+ salt) is completely ineffective.

Antimicrobial Synergistic Effect Between Ag and Zn in Ag-ZnO·mSiO2 Silicate Composite with High Specific Surface Area.

Antimicrobial materials are widely used for inhibition of microorganisms in the environment. It has been established that bacterial growth can be restrained by silver nanoparticles. Combining these with other antimicrobial agents, such as ZnO, may increase the antimicrobial activity and the use of carrier substrate makes the material easier to handle. In the paper, we present an antimicrobial nanocomposite based on silver nanoparticles nucleated in general silicate nanostructure ZnO·mSiO2. First, we prepared the silicate fine net nanostructure ZnO·mSiO2 with zinc content up to 30 wt% by precipitation of sodium water glass in zinc acetate solution. Silver nanoparticles were then formed within the material by photoreduction of AgNO3 on photoactive ZnO. This resulted into an Ag-ZnO·mSiO2 composite with silica gel-like morphology and the specific surface area of 250 m2/g. The composite, alongside with pure AgNO3 and clear ZnO·mSiO2, were successfully tested for antimicrobial activity on both gram-positive and gram-negative bacterial strains and yeast Candida albicans. With respect to the silver content, the minimal inhibition concentration of Ag-ZnO·mSiO2 was worse than AgNO3 only for gram-negative strains. Moreover, we found a positive synergistic antimicrobial effect between Ag and Zn agents. These properties create an efficient and easily applicable antimicrobial material in the form of powder.

Three-Dimensional Plasmonic Trap Array for Ultrasensitive Surface-Enhanced Raman Scattering Analysis of Single Cells.

Single-cell analysis provides an important strategy to evaluate cellular heterogeneity. Although surface-enhanced Raman scattering (SERS) has been considered as a promising label-free technique for single-cell analysis, it remains at the early stage for characterizing the extracellular metabolites of single cells. Herein, we developed a convenient, flexible, and straightforward three-dimensional (3D) plasmonic trap array for simultaneously compartmentalizing and sensitively detecting single-cell metabolites. The 3D trap was spontaneously self-formed by an interfacial-energy-driven process when a liquid droplet was covered with an immiscible oil liquid (polydimethylsiloxane, PDMS). When a droplet of pure AgNO3 solution was immersed into PDMS, Ag+ ions were automatically reduced by the residual Si-H groups in PDMS. Snowflake-like nanoparticles of Ag could be formed on the inner surface of the 3D traps by tuning the concentration of Ag salt precursors and then assembled to flower-like microstructures, endowing the traps with remarkable plasmon enhancement. The established 3D traps exhibited considerably enhanced surface plasmon resonance signals for Raman reporting, and a low detection limit at the aM level was achieved for p-aminothiophenol. Moreover, these 3D traps can serve as an efficient tool for single-cell SERS measurement. As a proof-of-concept, dipicolinic acid, a common biomarker of bacterial spores, was successfully detected from a single cell. The presented approach provides a versatile tool for label-free and sensitive detection of single-cell environments.

Cylindrical dielectric barrier discharge plasma catalytic effect on chemical methods of silver nano-particle production

In this study, cylindrical dielectric barrier discharge plasma was used to study the catalytic effect on chemical methods of silver nano-particles for the first time. In this method, the processing time is short and the temperature of reaction is low. Also, the reactor is very simple, inexpensive, and accessible. In this work, pure AgNO3 as the precursor agent and poly vinyl pyrrolidone as the macromolecular surfactant were dissolved in ethanol as the solvent. UV-Vis and XRD were used to identify the colloidal and powder nano-particles, respectively. Optical emission spectroscopy was also used to identify the active species in plasma. Effects of gas flow rate, voltage, volume of solution, and processing time were also studied. Moreover, TEM and SEM images presented the mean diameter of nano-particle size around 10 to 20 nm. The results have been very promising.

Silver Growth on AFM Tip Apexes from Silver Nitrate Solutions Triggered by Focused-Ion-Beam Irradiation

Silver nanostructures are directly grown on the apex of commercially available silicon AFM probes using our area-selective electroless deposition: the apex of a silicon AFM probe is irradiated using a focused ion beam (FIB), and then the FIB-irradiated AFM probe is exposed to a pure AgNO3 aqueous solution. With this method, a silver nanostructure selectively grows on the tip apex where the native oxide layer has been removed in response to FIB irradiation. Silver ions are reduced by the electrons flowing from the silicon probes into the solution through the FIB-irradiated area owing to the difference in Fermi energy between silicon and the solution. The morphology of the growing silver depends on the concentration of both AgNO3 and the electrons. The growth of a gold nanoflower is also demonstrated on the apex of a silicon AFM probe.

In Vitro Antibacterial Activity and Mechanism of Silver Nanoparticles against Foodborne Pathogens.

Biosynthesis of silver nanoparticles using Planomicrobium sp. and to explore the antibacterial activity against food borne pathogenic bacteria Bacillus subtilis, (3053) Klebsiella planticola (2727) Klebsiella pneumoniae (MAA) Serratia nematodiphila (CAA) and Escherichia coli. In the current studies, 1 mM of silver nitrate was added into 100 mL of Planomicrobium sp. culture supernatant. The bioreduction of pure AgNO3 was characterized by UV-visible spectroscopy, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy-dispersive analysis (EDS), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) analysis. The formation of silver nanoparticles was confirmed by the presence of an absorption peak at 400 nm using UV-visible spectrophotometry. The morphology and size of the silver nanoparticles was monitored by TEM and SEM. Crystal structure was obtained by carrying out X-ray diffraction studies and it showed face centered cubic (FCC) structure. The bactericidal effect of silver nanoparticles was compared based on diameter of inhibition zone in well method. Bacterial sensitivity to nanoparticles a key factor in manufacture the suitable for long life application in food packaging and food safety. Food safety is a worldwide health goal and the food borne diseases get a main disaster on health. Therefore, controlling of bacterial pathogens in food is credit of harms associated to health and safety.

Bactericidal activity of bio mediated silver nanoparticles synthesized by Serratia nematodiphila

ObjectivesMicrobe mediated synthesis of silver nanoparticles by using Serratia nematodiphila and to explore the antibacterial activity against pathogenic bacteria Bacillus subtilis, Klebsiella planticola and Pseudomonas aeruginosa. MethodsThe present studies, 1 mM of silver nitrate was added into 100 ml of S. nematodiphila (CAA) culture supernatant. The bioreduction of pure AgNO3 were characterized by UV–visible spectroscopy, X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and Fourier transform infra-red (FTIR) analysis. ResultsIn this report, biosynthesized silver nanoparticles are confirmed by color changes and it was characterized by UV–visible spectrum of surface plasmon resonance at 420 nm. Transmission electron microscopy (TEM) showed the formation of well-dispersed silver nanoparticles in the range of 10–31 nm and X-ray diffraction value obtain from range of (200) confirmed synthesized silver nanoparticles in crystalline nature. The microbe mediated synthesized silver nanoparticles shows more zone of inhibition against the pathogenic bacteria B. subtilis, K. planticola and P. aeruginosa. ConclusionBiosynthesis of metal nanoparticles is an expanding research area due to the biomedical application for the growth of novel biotechnologies. The report suggests that the synthesized silver nanoparticles act as eco-friendly antibacterial agent.

Formation of AgFeO2, α-FeOOH, and Ag2O from mixed Fe(NO3)3–AgNO3 solutions at high pH

Precipitation of ternary oxide silver ferrite (AgFeO2), iron oxyhydroxide goethite (α-FeOOH) and silver(I) oxide (Ag2O) from mixed Fe(NO3)3–AgNO3 solutions in a whole [Ag+]:[Fe3+] concentration ratio range at high pH was investigated using X-ray powder diffraction (XRD), 57Fe Mössbauer, FT-IR and UV–Vis–NIR spectroscopies and field emission scanning electron microscopy (FE-SEM). Strong alkalis organic tetramethylammonium hydroxide (TMAH) or inorganic NaOH were used as precipitating agents. Monodispersed lath-like α-FeOOH particles were formed from a pure Fe(NO3)3 solution. The presence of Ag+ ions influenced the formation of the delafossite-type ternary oxide AgFeO2 beside α-FeOOH. The positions of XRD and Mössbauer lines did not suggest any significant incorporation of Ag+ ions into the α-FeOOH structure. AgFeO2 was formed in the precipitation system with the equimolar initial [Ag+]:[Fe3+] concentration ratio. The size and shape of AgFeO2 particles, as well as their structural polytype (2H or 3R), were dependent on reaction temperature, aging time and alkali used. In systems with an excess of Ag+ ions mixtures of AgFeO2 and Ag2O were formed. Single phase Ag2O precipitated from a pure AgNO3 solution.

Electrolytic nucleation and growth of silver crystals in silver nitrate melts containing oxidants

Silver crystal nucleation is studied in AgNO3 melts containing Pb(NO3)2 and HNO3 at 250°C by the galvanostatic method. The maximum nucleation overpotential is higher as compared with pure AgNO3 and the exchange current of silver deposition-dissolution is lower. It is found that the added substances and the products of their reactions with the melt are strong oxidants, take part in the electrochemical processes, and induce passivation of the cathodic substrate and the surface of growing silver crystals. Substantial changes in the morphology of the cathodic deposit and certain changes in the silver lattice parameter were observed depending on the oxidant content.

Synthesis of Ag Nanoplates on GaAs Wafers: Evidence for Growth Mechanism

Direct synthesis of Ag nanoplates on GaAs wafers has been developed in our group through a simple solution/solid interfacial reaction (SSIR) strategy, in which aqueous solutions of pure AgNO3 react with the GaAs wafers at room temperature [J. Phys. Chem. C 2009, 113, 6061; 2008, 112, 8928; Chem. Mater. 2007, 19, 5845]. However, a number of questions are still not clear yet regarding the roles of different possible pathways for reducing Ag+ ions in the growth of Ag nanoplates. In this article, we try to answer these remaining questions by specifically designing experiments and extracting direct evidence from systematic characterizations of different samples. It is conclusive that growth of high-quality Ag nanoplates on GaAs wafers is ascribed to the good separation between nucleation and growth steps, which are driven by two different reduction pathways. At the nucleation step, fast reduction of Ag+ ions with a high concentration of surface electrons is crucial for the formation of Ag nuclei with multiple ...

Thermodynamic Properties of Alkali Nitrate—Silver Nitrate Melts

Abstract EMF measurements were performed on a chemical cell containing a silver and a nitrate electrode. The systems NaNO3 + AgNO3 , LiNO3 + AgNO3, and pure AgNO3 were investigated in a temperature range of 240 °C to 310 °C and in the total concentration range permitted by the phase diagram. We found a linear dependence of the EMF on temperature. Six constants, characteristic for the investigated molten salts depending neither on composition nor on temperature, were determined by the analytical construction of the activity coefficients. Together with the analytically constructed excess molar Gibbs function, the excess molar entropy was calculated from calorimetric data in the literature.