Ag2O Content Research Articles

Cross-Link Density, Mechanical and Thermal Properties of Chloroprene Rubber Cross-Linked with Silver(I) Oxide.

The purpose of this work was to cross-link chloroprene rubber (CR) with silver(I) oxide (Ag2O) and to investigate the properties of the obtained vulcanizates. Silver(I) oxide was chosen as an alternative to zinc oxide (ZnO), which is part of the standard CR cross-linking system. The obtained results show that it is possible to cross-link chloroprene rubber with silver(I) oxide. This is evidenced by the determined vulcametric parameters, equilibrium swelling and elasticity constants. As the Ag2O content in the composition increases, the cross-link density of the vulcanizates also increases. However, the use of 1 phr of Ag2O is insufficient to obtain a suitably extensive network. Exclusively, the incorporation of 2 phr of Ag2O results in obtaining vulcanizates with great cross-link density. The obtained compositions are characterized by good mechanical properties, as evidenced by high tensile strength. The performed thermal analyses—differential scanning calorimetry (DSC) and thermogravimetry (TGA) allowed us to determine the course of composition cross-linking, but also to determine changes in their properties during heating. The results of the thermal analysis confirmed that CR can be cross-linked with Ag2O, and the increasing amount of oxide in the composition increases the degree of cross-linking of vulcanizates. However, the amount of Ag2O in the composition does not affect the processes occurring in the heated vulcanizate.

Examinations the optical, mechanical, and shielding properties of Ag2O doped B2O3\u2013Bi2O3\u2013SrF2\u2013Na2O glasses for gamma ray shield applications

A series of five glass samples have a chemical composition of (55-x) B2O3 + 5 Bi2O3 + 20SrF2 + 20Na2O + xAg2O with varied doping ratios x = 0, 1, 2, 3, and 4 mol% were fabricated using the melt quenching technique to study the effect of B2O3 replacement by Ag2O on the physical, mechanical, optical and gamma-ray shielding capacity of the fabricated glasses. The Cary 5000 UV–Vis–NIR measured the optical absorption in the wavelength range between 200 and 3000 nm. Based on the measured optical absorption, energy (direct/indirect) bandgap and Urbach energy were calculated. Moreover, the measured samples density, molar volume, packing density, dissociation energy, and mechanical properties for the fabricated glasses were calculated using the concepts of the Makishima-Mackenzie model. In this regard, the microhardness was decreased from 4.070 to 3.931 GPa with raising the Ag2O concentration. The effect of B2O3 replacement on the shielding capacity was also evaluated using the Monte Carlo simulation. The simulation results showed that the replacement of B2O3 causes a significant increase in the shielding parameters like linear attenuation coefficient and radiation shielding capacity. The best radiation shielding properties were achieved for a glass sample with 4 mol% Ag2O compound. Its linear attenuation coefficient varied between 8.091 and 0.134 cm−1, raising the gamma photon energy between 0.059 and 2.506 MeV.

Removal of iodide from water using halloysite/Ag2O composites as efficient adsorbent

The efficient removal of iodide (I−) from water is challenging to accomplish because of the large size and low charge of I−. In this study, halloysite/Ag2O composites were prepared, characterized, and used to remove I− from water. The Ag2O nanoparticles primarily resided in the lumen of halloysite in the composites, whose amount and size can be readily controlled by adjusting the concentration of Ag+ during the preparation process. Moreover, there is rapid adsorption of I− by the composites, whose kinetics followed a pseudo-second-order model. With a solid/liquid ratio of 50 mg/20 mL and an initial pH of 7.5 ± 0.2, the maximum I− adsorption capacity of composites with an approximately 0.98% and 2.42% Ag2O content was 13.7 mg/g and 39.99 mg/g, which is 48 and 142 times higher than that of raw halloysite, respectively. Importantly, the composites exhibited high selective adsorption to I−, and their I− removal efficiency is barely affected by the presence of Cl−, Br−, or SO42−. The high adsorption capacity of the composite is driven by the small particle sizes of Ag2O due to the spatial confinement of the lumen of halloysite and the newly formed nanopores between Ag2O particles and the inner wall of halloysite. After capturing the radioactive I−, the composites are expected to constitute a low radiological hazard because of the shielding provided by the halloysite wall. Taken together, these results suggest the halloysite/Ag2O composites could be a promising adsorbent suitable for use in the efficient removal of radioactive I− from nuclear wastewater.

Development of Ag and Ag alloys-precipitated Ag2O-TeO2 glass and Ag2O-TeO2 glass/stainless steel reference electrodes for pH sensors

An Ag/AgCl reference electrode that is built into commercially available pH electrodes leaks its internal KCl solution via a liquid junction. This leakage is disadvantageous because the test solution is contaminated by a trace amount of the KCl solution. The applicability of Ag2O-TeO2 glasses to reference electrodes for pH sensors was investigated in this study. The effects of the Ag2O content and heat treatment on the pH sensitivity of these glasses and the pH sensitivity of the Ag2O-TeO2 glass/stainless steel electrodes were examined. The pH sensitivity of Ag2O-TeO2 glasses increased as the Ag2O content increased, but it was less than 40 % and was the lowest among the glasses that have been investigated to date. The heat-treated 25Ag2O･75TeO2 glass and 25Ag2O･75TeO2 glass/stainless steel electrodes precipitated cubic Ag and hexagonal Ag and showed relatively low pH sensitivities of 26 % and 5 %, respectively. Thus, the hexagonal Ag and Ag alloys-precipitated samples were considered candidate reference electrodes for pH sensors.

Role of silver ions in Na2O-CaF2-P2O5 host glass and its corresponding glass-ceramic: Searching for antibacterial behavior-supplemented by spectral, optical, FTIR and SEM investigations

Glasses based on the base host Na2O-CaF2-P2O5 system with increasing Ag2O as additives or loading (0.2 to 1 wt%) were prepared by melting-annealing technique. Multiple characterizations of the prepared glasses were carried out. Heat- treatment of the glasses was done through a two-step protocol to convert them to their corresponding glass-ceramics derivatives. The state of silver ions was analyzed by additional optical and FTIR spectral beside SEM measurements. Antibacterial behavior of the Ag2+ ions in the studied glasses and their glass-ceramic derivatives was conducted by their response towards two G+ve strains (Staphylococcus aureus, Bacillus cereus), one G-ve bacterial strain (Escherichia coli), one yeast (Candida albicans) and one fungi (Aspergillus niger). Optical spectra show distinct UV absorption in the undoped glass spectrum and extend to near visible with increasing Ag2O content. This distinct UV absorption is assumed to originate from unavoidable trace iron (Fe3+) impurities while the peak at 420 nm is related to nanocrystalline (Ag0)n . FTIR spectra show vibrational spectra within the mid region 400-1650 cm-1 which are characteristic for phosphate (PO4) groups with some suggested (PO3F) groups. The dopant silver ions show no distinct effect on the FTIR spectra. After immersion in phosphate solution FTIR spectra of the glass-ceramic reveal the formation of hydroxyapatite layer. X-ray diffraction results indicate the formation of crystalline phosphate phases for the undoped glass-ceramic. Two silver crystalline phases are identified after addition of Ag2+ ions. SEM images confirm the formation of apatite layer with different additions of silver ion. The antibacterial analysis also indicate the promising effect of the glass-ceramics than their parent glass in the bioactivity applications.

Photon, proton, and neutron shielding capacity of optical tellurite-vanadate glass systems: Theoretical investigation

The influence of density and molar concentration of Ag2O on photon, proton, neutron, and alpha particle shielding capacity of tellurite-vanadate-silver glass systems with the form 40TeO2+(60-x)V2O5+xAg2O: x = 0–50 mol% (encoded as TVAg0- TVAg50) was evaluated and analyzed in a wide range of energy (0.015–15 MeV). Linear and mass attenuation coefficients (μ, μm), half value thickness (HVT), mean free path (MFP), and effective atomic number (Zeff) were evaluated via the free online program–Phy-X/PSD, while EBF and EABF were computed via EXABCal software. The maximum μm was obtained at the least photon energy (15 keV) with values equal to 29.702, 31.371, 32.949, 34.443, 35.86, and 37.205 cm2g-1 for TVAg0, TVAg10, TVAg20, TVAg30, TVAg40, and TVAg50, respectively. Generally, The μm of the glass's trends in the order: (μm)TVAg0 < (μm)TVAg10 < (μm)TVAg20 < (μm)TVAg30 < (μm)TVAg40 < (μm)TVAg50. The trend of μ amongst the glasses is like that of the mass attenuation coefficient. The values of the maximum MFP varied from 9.757 to 4.53 cm for TVAg0 and TVAg50, respectively. The HVT trend of TVAg-glasses obeys the order: (HVT)TVAg0 > (HVT)TVAg10 > (HVT)TVAg20 > (HVT)TVAg30 > (HVT)TVAg40 > (HVT)TVAg50. The range of Zeff for the glasses varied from: 14.8 to 42.38 for TVAg0 glass and from 26.06 to 47.63 for TVAg50 glass. The f-factor of the TVAg-glasses were lower than unity except that of TVAg50 at 5 MeV. The variations in buildup factors with photon energy is alike for all glass materials and depth of penetration (mfp). The projected range (PR) followed the order: (PR)TVAg0 > (PR)TVAg10 > (PR)TVAg20 > (PR)TVAg30 > (PR)TVAg40 > (PR)TVAg50 for both proton and α-particle. Mass stopping power (MSP) is inversely proportional to the atomic number of the target (TAVg-glasses). Results confirmed that density and molar concentration of Ag2O plays an important role for improving the radiation shielding capacity of the investigated TAVg-glasses.

Ag-doped phosphate glass with high weathering resistance for RPL dosimeter

Ag-doped phosphate glass employed in the commercial dosimeter named FD-7 is used globally as one of the most reliable dosimeter materials. The luminescence phenomenon is well known as radiophotoluminescence (RPL). In this work, a new RPL glass material was developed for dosimeters that are used under high humidity conditions. The glass material that contains Ag2O as an activation center was produced by the melt-quenching method. The radiation properties and the optimal amount of Ag2O concentration required for achieving the best performance of the glass were evaluated using the RPL read-out system employing the photon counting method. On exposure to UV laser light radiation, the new RPL glass developed in this work emitted light of an approximate wavelength of 650 nm after radiation exposure, and the RPL intensity was proportional to the exposed dose. In addition, the glass material exhibited high reusability owing to the repeated operation of irradiation and reset. On conducting the weathering resistance test for a long duration, it was found that the new RPL glass exhibited the same RPL intensity and appearance as its initial values.

Structural and nuclear shielding qualities of B2O3–PbO–Li2O glass system with different Ag2O substitution ratios

Structural and gamma-ray/neutron radiation protection characteristics of (50-x)B2O3 +40PbO+10Li2O + xAg2O (x = 0, 2.5, 5, 7.5, 10 wt fraction (wt) %) glass system encoded BPLA glasses have been extensively surveyed. The structure of the prepared glasses has been investigated over X-Ray Diffraction (XRD) patterns. With the addition of Ag2O, the glasses' amorphous structures have not deteriorated, and the density and molar volumes of BPLA glasses inversely varied. Mass attenuation coefficients (MAC) for BPLA glasses have been generated enjoying Monte Carlo N-Particle- Extended (MCNPX) simulation code for the broad gamma-ray energy range of 0.015–15 MeV. It has been observed that the MAC values of the BPLA10 glass are higher than the others at all energy levels. Furthermore, while Ag2O concentration in the glass has increased, Half Value Layer (HVLs) Energy Absorption and Exposure Buildup Factors (EABFs, and EBFs) have dropped off for photon energies which are important for shielding applications. It has been noticed from these results that owning higher equivalent atomic number (Zeq) values, BPLA10 can be employed effectively for gamma-ray attenuation. Lastly, the results found for fast neutron removal cross-sections (∑R) have shown that the Ag2O additive grew the density and ∑R values of the glasses. As with photon shielding, it is observed that BPLA10 glass can be more preferable in terms of neutron retention according to other glasses. One can conclude that Ag2O enhances the shielding capacity of the glass system studied and BPLA10 glass can be considered as a good material for gamma-rays/fast neutrons shielding.

Fabrication of p–n heterojunction Ag2O@Ce2O nanocomposites make enables to improve photocatalytic activity under visible light

The design of highly efficient heterostructure material having good photocatalytic efficiency is good technique for the degradation of organic pollutants. In this paper, a series of Ag2O/Ce2O p–n heterostructure were prepared via facile hydrothermal approach with varying concentration of Ag2O to Ce2O (0%, 2%, 4%, and 6%). The crystal structure, morphology, chemical composition, optical properties and photocatalytic activity of synthesized nanostructures were studied. All test verified the development of p–n heterostructure which has reduced band gap energy as well as lower recombination of charge carriers. Moreover, this novel p–n heterojunction showed excellent charge carrier separation and transfer ability, thus superior photocatalytic efficiency under visible photo-illumination towards the degradation of methyl orange dye. Among all samples. 4% Ag2O/Ce2O nanocomposite exhibited superior photocatalytic activity, which is greatly higher than pure Ag2O, Ce2O and other nanocomposites. These results indicate that the synthesized p–n heterojunction will provide significant advancement in environmental field.

Efficient removal for multiple pollutants via Ag2O/BiOBr heterojunction: A promoted photocatalytic process by valid electron transfer pathway

Multiple pollutants including pathogenic microorganism contaminations and emerging organic contaminations (EOCs) have shown a growing threat to the environment, especially the natural waters. However, the control and removal of pathogenic microorganism contaminations and EOCs have been greatly limited since limited knowledge of their environmental behaviors. Thus, a novel and efficient photocatalyst Ag2O/BiOBr heterojunction was synthesized and used for removal of multiple pollutants including Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), tetracycline and acetaminophen under visible light. The results showed that there were valid electron transfer pathways between BiOBr and Ag2O, the main electron transfer direction was the BiOBr to Ag2O. Photo-generated electrons were stored in Ag2O and thus separation efficiency between holes and photo-generated electrons was obviously enhanced. Active oxygen species were highly produced and eventually end up with the high efficiency of removal of multiple pollutants. For Ag2O/BiOBr with Ag2O content at 3% (the best performance) under visible light, log decrease of E. coli was 7.16 (removal efficiency was 100%) in 120 min, log decrease of S. aureus was 7.23 (removal efficiency was 100%) in 160 min, C/C0 of tetracycline was 0.06 in 180 min, C/C0 of acetaminophen was 0.17 in 180 min. This work could provide a promising candidate in the actual contaminated natural waters for cleaning multiple pollutants.

Impact of Ag2O on linear, nonlinear optical and gamma-ray shielding features of ternary silver vanadio-tellurite glasses: TeO2–V2O5–Ag2O

The influence of Ag2O on the linear and nonlinear optical parameters of ternary silver vanadio-tellurite glasses, with a chemical formula of 40TeO2-(60-y)V2O5-yAg2O where y = 0–50 mol% in increments of 10 mol%, was investigated. The effect of Ag2O on the gamma-ray shielding properties of the investigated glasses was evaluated utilizing the recently released Phy-X/PSD program. The results revealed that the linear optical refractive index varied between 2.47 and 2.66 for the studied glasses. The molar polarizability (αmolar) decreased from 14.125 × 10−24 to 9.634 × 10−24 cm3, while the molar refractivity (Rmolar) varied from 35.596 to 24.279 (cm3/mol) as the Ag2O concentration increased from 0 to 40 mol%. The metallization criterion (Mcriterion) varied from 0.246 to 0.280, while the optical transmission factor (Toptical) increased from 0.656 to 0.694. The static dielectric constant (εstatic) changed from 6.624 to 7.128, while optical electronegativity (χ*) increased from 0.580 to 0.731. The nonlinear optical susceptibility (χ3) varied from 6.923 × 10−12 to 9.637 × 10−12 esu, while the non-linear refractive index changed from 0.722 × 10−10 to 1.360 × 10−10 esu. The T40V60A0 glass sample (with no Ag2O) has the lowest μ/ρ and can shield 50.3% of the photons at an energy of 0.284 MeV, while T40V10A50 has the highest μ/ρ and can shield 78.5% of a beam of photons with the same energy. The MFP at 0.284 MeV has the following values: 2.145, 1.811, 1.470, 1.308, 1.130 and 0.975 cm for T40V60A0, T40V50A10, T40V40A20, T40V30A30, T40V20A40 and T40V10A50 glasses respectively. Altogether, the results demonstrated that the greater the Ag2O content in the glasses, the lower the TF, and thus the more effective the radiation shield. The investigated glasses have a great possibility of being applied in several optical applications.

Structure and low energy vibrations in silver borate glasses with low silver content

Structural changes of (Ag2O)x(B2O3)1-x glasses, over the range between X = 0.0 and X = 0.14, have been monitored by Raman spectroscopy. Low temperature heat capacity measurements have been also performed between 0.4 K and 25 K to investigate along with low frequency Raman scattering the behavior of the low-energy vibrational dynamics. A progressively decreasing intensity of the main band at 808 cm−1 and the appearance of a band at about 775 cm−1 with increasing Ag2O content have been observed and analyzed in detail. The strongly polarized band at 808 cm−1 is ascribed to the breathing vibration of boroxol rings and the decrease of its intensity indicates the reduction of the number of these units in the network. The band at 775 cm−1 is assigned to vibrations of pentaborate units, formed from two boroxol rings linked by a tetrahedral BO4 group. The rate of formation of BO4 groups appears to increase as X/(1-X). Raman investigation has been extended to very low frequencies, where a broad intense band, the Boson peak (BP), dominates the spectrum of all the samples below 100 cm−1. Addition of Ag2O shifts the BP position from 26 cm−1 up to 33 cm−1 and gives rise to a decrease of its intensity up to X = 0.09 and a sudden increase for X = 0.14, which has been explained as due to rattling motion of silver ions whose contribution is added to that of localized vibrations. The formation of tetrahedral BO4 groups stiffens the network and leads to a decrease of the excess heat capacity over the Debye prediction below 20 K, which is not taken into account by the simple hardening of the elastic continuum but seems to follow the reduction of boroxol rings. This result contrasts the observations on borate glasses with high Ag content and emphasizes the crucial role of the network continuity on the vibrational dynamics of a glass.

Impact of Ag2O Content on the Optical and Spectroscopic Properties of Fluoro-Phosphate Glasses.

Glasses with the system (84.60-x) NaPO3-5 ZnO-(9.40-x) NaF-x Ag2O-1 Er2O3, (x = 0, 2, 4, and 6) (mol%) were synthesized by the conventional melt-quenching method. The impact of the addition of Ag2O on the physical, thermal, structural, and optical properties of the glasses is discussed. The Judd-Oflet analysis was used to evaluate the radiative properties of the emission transitions of the glasses. The enhancement of luminescence properties due to Ag2O is discussed in terms of consequent changes in the local electromagnetic field, symmetry, and the ligand field around the Er3+ ion. The heat treatment of the glass was performed in order to precipitate Ag nanoparticles (NPs), which form as a layer at the surface of the heat-treated glasses as confirmed using scanning electron microscopy (SEM). The Ag NPs were found to increase the intensity of the emission at 1.5 µm.

Structural, electrical and magnetic properties of La0.625Ca0.285Sr0.09MnO3 polycrystalline ceramics doped with Ag2O

In this study, the doping effects of silver on the structural, electrical and magnetic properties of polycrystalline La0.625Ca0.285Sr0.09MnO3:Agx (LCSMO:Agxx = 0, 0.10, 0.20, 0.25, and 0.30) ceramics were investigated and the results were discussed. The ceramic specimens were prepared by the sol–gel method followed by sintering at 1673 K for 14 h. The optimization of ceramic properties, such relative high temperature coefficient of resistance (TCR) in the vicinity of room temperature was obtained by varying the Ag doping content. X-ray diffraction indicated that all specimens crystallized in typical orthorhombic perovskite phase with Pnma space group. Rietveld refinement data showed that structural parameters, such as Mn–O bond length, Mn–O−Mn bond angles and cell volumes were slightly modified when Ag content increased. Scanning electron microscopy depicted reduced grain boundaries and increased grain size when Ag content rose. Resistivity dependence of temperature curves (R−T) of LCSMO:Agx specimens were investigated by standard four-probe method, and R−T curves indicated decline in resistivity with Ag2O content. The specimen with x = 0.25 illustrated relatively high TCR value reaching 4.60%/K near room temperature (310.06 K). X-ray photoelectron spectroscopy revealed that Ag+ could increase Mn4+ ion concentration since Ag+ ion may replace La3+, Ca2+ and Sr2+ ions at A-sites. The magnetoresistance measured at low magnetic field of 0.8 T suggested enhancement in low field magnetoresistance of LCSMO:Agx ceramics with x. Overall, the prepared ceramics look promising for applications in bolometric infrared detectors.

Sputtering control of Ag2O decoration configurations on ZnO nanorods and their surface arrangement effects on photodegradation ability toward methyl orange

In this study, a combinational strategy for synthesizing ZnO nanorod arrays interlaced with Ag2O particles was proposed. Hydrothermally derived ZnO nanorod templates were sputter coated with Ag2O particles. The sputtered Ag2O particles can be decorated on the surfaces of the ZnO nanorod arrays with a randomly dispersive or continuous coverage characteristic by controlling the sputtering duration. Structural analysis revealed the formation of satisfactory crystalline ZnO–Ag2O composite nanorods through the hydrothermal and sputtering methods. The ZnO–Ag2O composite nanorods exhibited a significantly enhanced photoactivity compared with that of pristine ZnO nanorods under light irradiation. Moreover, the Ag2O content and the coverage feature of the ZnO–Ag2O composite nanorods influence the photodegradation of methyl orange solution by the composite nanorods under light irradiation. The photodegradation efficiency of the ZnO nanorods was substantially enhanced when the Ag2O particles were decorated on the surfaces in a dispersive manner. This can be attributed to the optimal content of Ag2O particles and their randomly dispersive characteristic on the surface of the composite nanorods, which resulted in the efficient transfer of photocarriers and markedly suppressed the electron–hole recombination rate.

Microstructure, bio-corrosion and biological property of Ag-incorporated TiO2 coatings: Influence of Ag2O contents

In the present work, the influence of Ag2O content on the microstructural feature, bio-corrosion behaviour and biological property of the resultant Ag-incorporated TiO2 micro-arc oxidation (MAO) coating is investigated. It is revealed that, with the addition of an increased amount of Ag2O nanoparticles (NPs) in the MAO electrolyte, a less defective Ag-incorporated TiO2 coating with pores of decreased dimensions could be produced, which also exhibits a higher anatase-to-rutile ratio along with a lower Ag2O-to-Ag ratio. Further, both antibacterial capability and bone formability of Ag-incorporated TiO2 coatings were investigated. The results show that the addition of an increased amount of Ag2O NPs enhances antibacterial capability of the resultant coating, which also exhibits desirable biocompatibility. This work offers a promising fabrication method for dual functional Ag-incorporated TiO2 coating with Ag2O NPs as Ag source.

Structural and dielectric features of silver doped sodium antimonate glass ceramics

The objective of this work is to explore the Ag ion concentration dependence on structural and dielectric characteristics of Na2OSb2O3: Ag2O glass ceramics. The prepared glass ceramics were characterized by XRD, XPS, SEM, TEM, EDS and DSC techniques. These studies have revealed that the samples are composed of multiple crystal grains entrenched in the remnant amorphous phase. The IR and Raman spectroscopic studies indicated increasing degree of polymerization of the glass network with increase of Ag2O concentration up to 0.1 mol%. This is attributed to increasing concentration of tetrahedral Sb5+ ions that take part in the glass network forming. Optical absorption spectra have exhibited surface plasmon resonance (SPR) band in the wavelength region 400–450 nm. Quantitative studies on dielectric properties were performed over wide ranges of frequency and temperature and the variations of these properties with the concentration of Ag2O are discussed in the light of various polarization processes. Dipolar orientational effects exhibited by electric moduli spectra suggested multiple relaxation times for electric dipoles. The observed decrease of A.C. conductivity (that contains both ionic and polaronic components) with increase of Ag2O content up to 0.1 mol% is attributed to the increasing degree of polymerization of the glass network that hinders the migration of charge carriers. The polaronic conduction is understood due to exchange of polarons between Sb3+ ‒ Sb5+ and Ag0 Ag+ ions, while ionic conductivity is predicted due to transport of monovalent silver and Na+ ions. A changeover of polaronic to ionic conductivity seemed to take place at about 0.1 mol% Ag2O.

Effect of silver oxide on hydroxy carbonated apatite formation for simulated body fluid soaked calcium phospho silicate system

Abstract In the present work, we have synthesized the 58SiO2-(38-x) CaO-xAg2O-4P2O5 glasses using sol-gel method and these glasses were treated for 7 days in simulated body fluid (SBF) solution. The structural properties of SBF treated samples were studied using characterization techniques such as X-ray diffraction (XRD) technique and scanning electron microscopy (SEM). Dissolution studies also have been studied for SBF treated samples. The XRD pattern indicates that crystalline nature increases with increase in Ag2O for synthesizing samples. The formed Hydroxy Carbonated Apatite (HCA) particles were identified by XRD and EDX analysis. Dissolution studies confirmed that HCA formation decreased with Ag2O content. Finally, it was confirmed that Ag2O content resists the HCA formation.

Glass-ceramic nanoparticles in the Ag2O–TeO2–V2O5 system: Antibacterial and bactericidal potential, their structural and extended XRD analysis by using Williamson–Smallman approach

Goals of this work lye in attempts to fabricate Ag2O–TeO2–V2O5 glasses (Gs) and glass-ceramics (GCs), determination of the mean square lattice strain and dislocation density by using Williamson–Smallman method and specially detection of their antibacterial activity against two gram-negative bacteria of Escherichia coli and Kelbesiella pneumoniae and also two gram-positive bacteria of Staphylococcus aureus and Bacillus cereus. The xAg2O–40TeO2–(60-x)V2O5 (0 ≤ x ≤ 50 mol%) ternary glasses, were obtained using the melt quenching method and so, resulted glasses were annealed at their specified crystallization temperature (Tcr) to achieve the glass-ceramics. Then, the Williamson–Smallman method was used to determine the mean square lattice strain and dislocation density. Further structural investigations were done by FESEM, EDX and TEM. Also, serial dilution bioassay was performed against both before-mentioned gram positive and gram negative bacteria (as test strains) to assess their antibacterial activity. Results show that the highest antibacterial and bactericidal potential is devoted to G and GCs sample with x = 30, as the optimal Ag2O content. Moreover, the antibacterial activity of the Gs and GCs on Staphylococcus aureus bacteria is higher than Bacillus cereus bacteria and in the case of gram negative's, Escherichia coli exhibit a more inhibition and bactericidal effect at x = 30%; in brief, the studied samples are good candidates in biological applications.

Influence of silver ion concentration on dielectric characteristics of Li2O-Nb2O5-P2O5 glasses

In this work we have studied the dielectric properties of Li2O-Nb2O5-P2O5: Ag2O glasses as a function of Ag2O concentration. Auxiliary studies viz., optical absorption, photoluminescence (PL), XPS and IR spectra have also been performed on these glasses. IR spectral studies have indicated that the host glass network doped with 1.0 mol% of Ag2O is highly polymerized. Optical absorption and PL studies have clearly exhibited absorption and emission bands due to surface plasmon resonance (SPR). From these studies, the presence of Ag0 -Ag+ clusters is established in the glass network and the concentration of such clusters is found to be the highest in the glass doped with 1.0 mol% of Ag2O. Finally, we have performed extensive studies on dielectric properties viz., dielectric constant, loss, electric moduli, impedance spectra and a.c. conductivity over broad ranges of frequency (0.01 Hz–1 MHz) and temperature (303–513 K). The glasses doped with higher content of Ag2O exhibited higher values of dielectric constant especially at lower frequencies and higher temperatures. The larger contribution from space charge polarization is predicted to be responsible for such higher values. In the glasses doped with low contents of Ag2O (<1.0 mol%) the polaron conductivity (due to the polaronic transfer between Ag0 and Ag+ ions) seemed to be dominant, whereas in the glasses containing more than 1.0 mol% of Ag2O, the ionic conduction (due to the diffusion of Ag+ and Li+ ions) appear to prevail. The impedance diagrams drawn between Z′ and Z″ have further supported the above-mentioned conclusions. From the overall analysis of the results of dielectric properties (including a.c. conductivity) with the aid of experimental results on spectroscopic studies, it is concluded that the glass containing more than 1.0 mol% of Ag2O exhibited predominantly ionic conductivity and hence such glasses may be useful as electrolytes for ionic conducting batteries.