Oxides PbO Research Articles

Design of New Sensor Functionalized with Green Nanoparticles PbO@Hyphaene Thebaica for in‐situ Amoxicillin Monitoring in Real Media

AbstractThe present work reports for the first time the design of an electrochemical sensor functionalized with green nanoparticles based on Hyphaene thebaica for amoxicillin quantification. Based on a simple one‐pot bio‐reduction reaction, lead oxide PbO coated with Hyphaene thebaica was synthesized. Ultraviolet‐visible spectroscopy (UV), fourier transform infrared (FITR), transmission electron microscopy (TEM) and X‐ray diffraction (XRD) were used to control optical, structural, morphological, and physicochemical properties of the elaborated nanoparticles. Results demonstrated a good dispersion with a spherical morphology, which is in the order 8 nm. Regarding the good properties of nanoparticles, they are integrated to design an electrochemical sensor for amoxicillin detection. Cyclic voltammetry and square wave voltammetry were used to follow up the sensor modification and the electrochemical sensor response versus different amoxicillin concentrations. Under optimal conditions, the electrochemical sensor modified with the nanoparticles in question provides a linear detection in the range 50–10000 nM, with a detection limit of 0.105 nM. The proposed sensor also exhibits good sensitivity and selectivity against several antibiotic analogues and has been successfully applied to real samples. Aside from its power in several fields including antibacterial, antifungal, enzyme‐inhibiting and antioxidant, green nanoparticles based on Hyphaene thebaica have demonstrated an effectiveness as a sensor for the electrochemical detection of amoxicillin, highlighting the possibility of adopting these sensors as routine test for the environment monitoring.

Role of Side Reaction Involving PbOx in Soluble Lead Redox Flow Battery: Effect on Cyclability

Soluble lead redox flow battery (SLRFB) has been an active subject of investigation in the past two decades because of its high energy efficiency (~70%) and charge efficiency (~90%) [1]. During charging, Pb2+ ions deposit as solid lead dioxide (PbO2 ) on anode and solid lead (Pb) on cathode, respectively. These features permit a membrane-less single-compartment design, making SLRFB a cost-effective electrochemical energy storage device. Discharge occurs by electro-dissolution of these solids, regenerating the electrolyte. The limited cycle-life of SLRFB is its current deployment challenge (best achieved about 100 cycles [2]). The shedding of solid lead dioxide over cycling is an indirect irreversible loss of active material from the electrolyte, the reason for SLRFB’s limited cyclability.Mathematical models link the deposit formation and the two-step charging potential profile through a side reaction involving PbO and PbO2 [3-5]. Morphological changes in deposit during cycling have been reported and presented as an alternate justification to the two-step potential profile [6]. To clarify these, we tested the role and feasibility of re-oxidation of solid PbO on cycling under varied conditions using an in-house prepared Nafion membrane-divided cell. We show that the charging through side reaction does not occur without the availability of Pb2+ near the electrode. We also show that the observations are independent of the electrodes’ age, the amounts of PbO and PbO2 present, and the applied current density. We obtained FESEM images of anode after short re-charging in a single-compartment design. We observed the formation of a new phase, plausibly lead dioxide from Pb2+ ions, leaving the solid residue almost unaffected. These findings challenge the idea of charging sustained in part by the oxidation of PbO through the side reaction. The deposit, constituted by whisker-like particles (thickness~200 nm), appears weak and layered. Gas evolution reactions known to occur under the limited availability of Pb2+ ions may promote residue disintegration. These observations lead us to hypothesize that cycling leads to irrecoverable residue accumulation, which may negligibly participate in further re-oxidation through the side reaction. These cumulative effects, accompanied by formation of a new phase at every charging, appear to contribute significantly to restricting SLRFB to a short cycle-life. These features raise concerns about the prevailing hypotheses about SLRFB dynamics and suggest need for strict design and operational controls to avoid residue buildup.

High performance adsorption efficiency of metal oxides towards potassium dichromate

The potassium dichromate (K2Cr2O7) is mostly used as an oxidizing agent in a variety of industrial and laboratory. It poses both immediate and long-term health risks, just like any other compound containing hexavalent chromium. Therefore, its adsorption process on the surface of a different metal oxides of PbO and MgO nanoparticles is thoroughly investigated in this work. Both structural and optical properties have been investigated for these metal oxides using XRD, HRTEM and UV vis spectroscopy. The XRD diffraction peaks confirmed the phases of both PbO and MgO NPs. Moreover, the crystallinity of PbO and MgO is 93,63 % and 95.25 %, respectively. The present metal oxides showed irregular shape such as spherical like shape and Quasi-spherical or rod- like shapes for PbO and MgO NPs. According to the results of the adsorption studies, The PbO NPs shows a high adsorption efficiency of 70 % towards potassium dichromate. The present results illustrated that both metal oxides may be used as an adsorbent to break down Potassium dichromate.

Evaluation of shielding properties of a developed nanocomposite from intercalated attapulgite clay by Cd/Pb oxides nanoparticles

The study investigated new nanocomposites’ γ-ray and neutron shielding properties based on raw attapulgite, a clay matrix intercalated with different weight percentages of mixed nano metal oxides CdO and PbO. The various percentages were as follows: (100–2x)% Attapulgite + x%CdO + x%PbO, abbreviated as (AT100–2x CdxPb x ), where x = 5, 10, 15%. The nanocomposites were characterized using XRD, FTIR, and EDX, confirming their successful preparation. SEM images revealed that the mixed oxide nanoparticles were successfully intercalated into the layers of attapulgite clay, with an average particle size of approximately 31.46 nm. The bulk densities of the prepared nanocomposites were measured to be in the range of 2.034 to 2.555 g/cm3. GEANT4 simulations were employed to evaluate the nanocomposites’ γ-ray and neutron shielding performance in the photon energy range of 0.015 to 15 MeV. Phys-X code was used for verification. The simulation results showed a maximum difference of approximately 9.5% between GEANT4 and Phys-X predictions. To assess the γ-ray shielding performance, various shielding parameters were calculated at selected photon energies. The μ m values ranged from 4.589 to 0.020 cm2.g−1, 6.311 to 0.021 cm2.g−1, 8.350 to 0.022 cm2.g−1 and 10.804 to 0.023 cm2.g−1 for raw attapulgite, AT90Pb5Cd5, AT80Pb10Cd10, AT70Pb15Cd15 across the photon energy range. The AT70Pb15Cd15 nanocomposite exhibited the highest μ m , Z eff , Z eq , and the lowest T 1/2, T 1/10, and MFP values. Notably, it also demonstrated the highest FNRCS (approximately 0.1 cm−1). These findings suggest that clay-based nanocomposites represent a new class of low-cost, locally available advanced materials with potential applications in γ-ray and neutron shielding characteristics.

Influence of various metal oxides (PbO, Fe2O3, MgO, and Al2O3) on the mechanical properties and γ-ray attenuation performance of zinc barium borate glasses

The current work aims to fabricate metal oxide-doped (PbO, Fe2O3, MgO, and Al2O3, each of which boasts a purity of 99%) zinc barium borate glasses through the melt quenching technique at the 1000 °C melting temperature. The results showed that adding 5 mol.% of metal oxides PbO, Fe2O3, Al2O3, and MgO increases the density of the zinc barium borate glasses. Additionally, the fabricated glasses' mechanical properties were determined based on the Makishima-Mackenzie model, which proved that the highest mechanical properties were achieved for glasses doped with Al2O3 compounds. The mechanical moduli for the glasses doped with Al2O3 reach 80.95 GPa (Young), 59.90 GPa (bulk), 31.75 GPa (shear), and 102.23 GPa (longitudinal). Additionally, the Al2O3-doped glasses' microhardness reaches 4.77 GPa. Moreover, estimation of the fabricated glasses' gamma-ray shielding capacity utilized Monte Carlo simulation. The highest linear attenuation coefficients are 29.132, 19.906, 19.243, and 18.923 cm−1 obtained at 0.033 MeV for glasses dopped by PbO, Fe2O3, MgO, and Al2O3, respectively. Therefore, glasses doped with 5 mol.% of PbO have high gamma-ray shielding capacities followed by glasses doped by Fe2O3.

Infrared Spectroscopy Study of Pure Oxides PbO, SnO2 and their Comparison

Nanocrystals of semiconducting metal oxides have attracted great interest due to their interesting properties. Therefore, our study came to some physical properties of pure tin oxide and pure lead oxide. Infrared spectral measurements of pure tin and lead oxides showed the presence of vibrational frequencies containing five frequencies for tin oxide and nine vibrational frequencies for lead oxide. The permeability spectra of the SnO2 and PbO compounds were measured, and we calculated each of n, A α , σopt and it was found through the comparison of these amounts for the two compounds that the optical conductivity = 1.214687 (Ωcm)-1, n=9.949 A=2, α=46 cm-1, All previous values are in agreement with the same vibrational frequency of υ = 3450 cm-1 for the lead oxide compound, which is the highest possible.

Gadolinium-based ceramics doped with lead oxide for γ-ray shielding

In this study, gadolinium-based ceramics (GdBa2Cu3Oy) doped with lead oxide (PbO) were prepared using the solid-state reaction approach. The effect of different PbO concentrations (x = 0.0, 2.0, 5.0, 10.0 wt%) on the structure, physical and optical peculiarities of GdBa2Cu3Oy lead oxide was investigated. The radiation attenuation characteristics were also estimated using Monte Carlo simulations. It was observed that the inclusion of PbO from 0.0 wt.% to 10.0 wt.% led to a significant change in the physical parameters of the prepared ceramics. The density of ceramics increased from 4.42 g/cm3 for x = 0.0 wt% to 4.53, 4.64, and 4.72 g/cm3 for x = 2.0, 5.0, and 10.0 wt%, respectively. The X-ray diffraction results showed that the pure GdBa2Cu3Oy ceramic was indexed as a polycrystalline orthorhombic phase. Some peaks related to BaPbO3 impurities were observed for the PbO-doped ceramics. The crystal size was found in the range of 21.1–41.18 nm, and the lattice strain was increased by adding PbO. The energy bandgap of the GdBa2Cu3Oy-doped PbO oxide was changed from 0.59 to 1.56 V with increasing PbO concentration up to 10.0 wt%. The prepared ceramics have shown good performance in radiation protection. The linear attenuation coefficient for the synthesized ceramic samples was examined utilizing the Monte Carlo N- particle transport code (MCNP), for the emitted gamma photons with energies varied in the interval extended from 0.15 to 15 MeV.

Thermodynamic Analysis and Experimental Study on the Oxidation of PbX (X = S, Se) Nanostructured Layers.

Heat treatment in an oxygen-containing medium is a necessary procedure in the technology of forming photodetectors and emitters based on lead chalcogenides. Lead chalcogenide layers (PbS, PbSe) were prepared via a chemical bath deposition method. Surface oxidation of lead chalcogenide layers was analyzed using X-ray diffraction and Raman spectroscopy methods, and thermodynamic analysis of the oxidation of PbSe and PbS layers was also performed. The calculated phase diagrams from 20 °C to 500 °C showed good agreement with the experimental results. According to the thermodynamic analysis, the oxidation products depend on the initial composition of the layers and temperature of the annealing. In some cases, the formation of a separate metallic phase Pb is possible along with the formation of lead oxide PbO and other oxides. The performed thermodynamic analysis makes it possible to substantiate the two-stage annealing temperature regimes which ensure an increase in the speed of photodetectors.

Impact effect of gamma irradiation on the optical, FTIR, ESR spectral properties and thermal behavior of some mixed (PbO + Bi2O3) borate glasses searching for shielding effects

Four borate glasses with mixed and equal heavy metal oxides PbO+Bi2O3 ranging from 70→55% were prepared by routine melting and annealing technique. These glasses were selected to identify the effects of gamma irradiation on glasses combining two heavy metal oxides (PbO, and Bi2O3) which are known to be of shielding nature towards irradiation. Collective measurements of the optical, structural FTIR and ESR. spectral properties of the prepared equal mixed glasses were carried out before and after a relatively high dose of gamma rays (6 M rad). Optical spectra of the glasses reveal before irradiation strong UV absorption due to trace ferric ions present as impurities in the chemicals used for the preparation of the glasses. After irradiation, an extra small induced near-visible band at 420 nm has been identified and is attributed to the creation of an induced boron- oxygen hole center (BOHC) or nonbridging oxygen hole center (NBOHC). FTIR spectra reveal distinct vibrational bands due to triangular (BO3 groups) and tetrahedral (BO4 groups) within their variant characteristic wavenumbers. Also, the condensed intensities of the FTIR bands refer to the sharing of vibrations due to PbO or BiO within their specific sites as evidenced by the deconvoluted spectra. Gamma irradiation causes no variations on the FTIR and ESR spectra confirming the shielding effect of the heavy metal oxides present in mixed percentages.

Structural Characterization of (Mg(1-x)pbxO)-NPs by Modified Pechini Method

The structural characterization was discussed in the present paper of the pure MgO nanoparticles and the doped (Mg(1-x)pbxO) nanoparticles specimens, where (0 ≤ x ≤ 0.03). The modified Pechini method was used to prepare all the specimens. From (DTA), the convenient temperature of decomposition from Mg(OH)2 to MgO was above 375°C. The structure investigation (XRD) revealed that all the specimens have identical space groups and index well to cubic structures. The obtained crystallite size by Scherrer''s equation was increased with increasing the fraction of doping except for (Mg0.97Pb0.03O) due to the formation of PbO oxide. The molecular vibration by FTIR demonstrated that all the pure and doped specimens have the same framework. As the incorporation of Pb2+ ions increases, the bands get broader, and the intensities increase in the ranging 800-400 cm-1 due to vibrations of O-Mg and O-Pb bands, respectively.

Synthesis, crystal structure and thermodynamic properties of apatite Pb-=SUB=-3-=/SUB=-Bi-=SUB=-2-=/SUB=-(GeO_4)-=SUB=-3-=/SUB=-

Apatite Pb3Bi2(GeO_4)3 was obtained by the solid-phase method from the initial oxides of PbO, Bi2O3 and GeO2 by sequential firing in air at temperatures of 773-1003 K. Its crystal structure has been refined by X-ray diffraction. The high-temperature heat capacity (350-1000 K) of this compound was measured by differential scanning calorimetry. Based on these data, the main thermodynamic functions are calculated. Keywords: apatite bismuth-lead germanate, solid-phase synthesis, high-temperature heat capacity, thermodynamic properties Keywords: apatite bismuth-lead germanate, solid-phase synthesis, high-temperature heat capacity, thermodynamic properties.

Synthesis, crystal structure and high-temperature heat capacity of substituted apatites Pb-=SUB=-9-=/SUB=-R(GeO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-(VO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=- (R=Tb, Dy, Ho)

Pb9R(GeO4)3(VO4)3 (R=Tb, Dy, Ho) apatites were obtained by solid-phase synthesis from the initial oxides of PbO, Tb2O3 (Dy2O3, Ho2O3), GeO2 and V2O5 by sequential annealing (at a temperature of 773-1073 K) in an air atmosphere. Their crystal structure has been determined by X-ray diffraction analysis. The high-temperature heat capacity was measured by differential scanning calorimetry. Based on the experimental dependence of the heat capacity on the temperature, the thermodynamic properties are calculated. Keywords: apatites, solid-phase synthesis, crystal structure, heat capacity, thermodynamic properties. Keywords: apatites, solid-phase synthesis, crystal structure, heat capacity, thermodynamic properties.

Li2O-K2O-B2O3-PbO glass system: Optical and gamma-ray shielding investigations

A Li2O-K2O-B2O3-PbO glass system has been synthesized through the melt quenching technique. The indirect bandgap energies were obtained from the recorded UV–visible spectra. It is confirmed that as the concentration of PbO increases, the indirect bandgap energies increases. While the refractive index, and the optical dielectric constant (pdpdt) decrease. The reflection loss (RL), as well as optical transmission coefficient (T) of the glasses, follow the opposite trend with PbO content. While the molar refraction (Rm) and electronic polarizability (αm) increase, the electronic polarizability (αe) decreases as the mol percentage of PbO rise in the glass matrix. The metallization (M) is <1, hence, the investigated glass samples show non-metallic nature. On the other hand, replacing B2O3 with PbO oxide increases the mass attenuation coefficient (MAC) of the samples, which in turn increases their radiation shielding effectiveness. The more B2O3 oxide is replaced with PbO oxide, the greater the effect in elevating their capabilities in shielding radiation especially for low gamma energies. The glass samples under investigation outperformed most of the radiation shields that were previously fabricated. With the increase of PbO levels, the half-value layer reduces due to the rise in the density of the samples. The Pb20 sample had the lowest TVL at all tested energies, demonstrating that it is the most efficient for radiation shielding applications.

A chemical model to predict the formation of a semiconductor solid solution: New insights in the use of bulk and surface mechanochemical reactions

A chemical model capable of predicting the formation of a semiconductor solid solution, via high-energy milling of powder precursors, is proposed. According to experimental findings provided by X-ray powder diffraction and X-ray photoelectron spectrometry, the model encompasses three major stages related to a series of oxygen levels, which are function of oxygen potential during milling. The initial step involves the formation of oxide mixtures, as evidenced by oxidizing highly reactive chalcogens (Se and Te) and re oxidation of PbO. In the middle step, which represents the largest process stage, Te or Se share electrons to act as Te (IV) and Se (IV) in order to form Pb complex chalcoxides. The formation of high purity Pb2SeTe semiconductor solid solution is detected at the final stage, in such stage the chalcogens act as reducing agents. Consequently, neither inert nor high vacuum atmospheres are required during the milling process. The model involves a quaternary interpretation whose predictions are validated with experimental findings, theoretical, and even analogous phases not reported so far in literature.

Synthesis and Structural Study of Ferroelectric Material Lead Titanate (PbTiO3)

Lead Titanate PbTiO3, (PT) is technologically important ferroelectric and piezoelectric ceramics. To make PbTiO3, the oxides PbO and TiO2 are combined in a stoichiometric ratio. Solid-state reaction process was used to synthesize the oxides. The calcination temperature was 8500C. The prepared sample has been characterized by XRD techniques with a scanning rate of 6 degree per minutes. The prepared sample PbTiO3 shows crystalline nature, with Tetragonal symmetry, as observed by X –ray measurements. A scanning electron microscope (SEM) was used to examine the surface morphology and grain size of the obtained samples. Micrographs obtained from SEM analysis revealed a single phase sample of well-defined grains.

The Calcination Temperature Effect on the Phase Formation of the PZT Ceramic: How the same Calcination Temperature, Result in Different Phase’s Formation

First, the metallic oxides of PbO, TiO2 and ZrO2 were mixed following (2, 1, 1) molar mass respectively. Then 4 samples were separated (S1, S2, S3 and S4). the first one S1 was subjected to calcination treatments at 600, 700 and 800 °C however, the S2 was treated at 700 °C only, the S3 at 800 °C and S4 at 850 °C. The X ray diffraction of the samples reveals important difference in the phases obtained, at 600 °C the quadratic riche phase of PbTiO3 was mainly observed on sample S1, after the treatment at 700 °C and 800°C, the same XRD patterns were obtained with the same peaks positions and the relative intensity. However the S2 revels different pattern from S1 at 700 °C relative to the formation of the Pb(Zr0.75, Ti0.25)O3 Rhombohedral riche phase. The S3 XRD results reveal also different pattern from S1 at 800 °C relative to the formation of Pb (Zr0.58, Ti0.42) O3 near the Morphotropic phase boundary (MPB) and the S4 confirm these finding. Thin films grown from the S1 and S4 used as target in the RF sputtering system, show important difference in the PZT stoichiometry obtained which is relative to Pb (Zr0.44, Ti0.56) located in the quadratic riche phase and Pb (Zr0.52, Ti0.48) O3 near the MPB respectively.

Синтез, структура и теплофизические свойства апатитов Pb-=SUB=-1-x-=/SUB=-Bi-=SUB=-x-=/SUB=-(GeO-=SUB=-4-=/SUB=-)-=SUB=-2+x-=/SUB=-VO-=SUB=-4-=/SUB=-)-=SUB=-4-x-=/SUB=- (x=0-3) в области 350-950 K

The compounds Pb10 ‒ xBix(GeO4)2+x(VO4)4-x (x = 0-3) with an aatite structure were first synthesized from the initial oxides of PbO, Bi2O3, GeO2 and V2O5 by solid ‒ phase synthesis with annealing in air in the temperature range of 773-1073 K. Their structure was determined using x-ray diffraction analysis. The influence of temperature on the heat capacity of synthesized compounds was studied using differential scanning calorimetry. Using the experimental data on Cp = f(T), the thermodynamic properties of the compound have been calculated.

Thermomechanical and Dielectric Properties Mesocomposites Based Polyepoxy, Metal Oxides and Polyaniline Hardened in Constant Physical Fields

The specimens of polyepoxy and mesocomposites on the base metal oxides CdO, PbO, Cr2O3, or mixtures thereof in the presence of polyaniline have been studied by methods of thermomechanical and dielectric analsis. Blending physical fields during curing samples stimulates reduction of activation energy, but also contributes to the glass transition temperature and confirms the conclusion set conformational change in the interstitial fragments forming a grid Chemical oxirane polymers under the influence of external physical fields. Differences tanhesa dielectric loss determined topological structure changes due to the influence of external factors on the reaction polipryyednannya and forming a three-dimensional grid. It was found decisive role interaction EP « МеО turnaround in determining the structure and characteristics mezokompozytiv based acid-base properties of metal oxide. Therefore, the use of metal oxides with different redox properties makes it possible to widely change thermomechanical and dielectric properties.

High-Temperature Heat Capacity of Pb10 – xNdx(GeO4)2 + x(VO4)4 – x (x = 0–3) Apatites

We obtained Pb10 – xNdx(GeO4)2 + x(VO4)4 – x (x = 0–3) compounds with an apatite structure by solid-phase synthesis from initial oxides PbO, Nd2O3, GeO2, and V2O5 with successive annealing at 773–1073 K in the air. Their high-temperature heat capacity was measured by differential scanning calorimetry. The thermodynamic functions (changes in enthalpy, entropy, and reduced Gibbs energy) are calculated using the experimental dependences of Cp = f(T).

Vaporization and caloric studies on yellow lead oxide PbO

The vaporization of pure yellow PbO(c) to provide reference data for lead titanate and other lead oxide containing compounds was investigated at temperatures of 810–1040 K. Thermodynamic quantities of sublimation and reaction enthalpies, and entropy were derived from the partial pressures of gaseous Pb, PbO, and O2 over pure yellow lead oxide. The experimental sublimation enthalpy of Pb from PbO(c) was ΔsubH930K0(Pb)=(206±5)kJmol−1, ΔsubH298K0(Pb)=(215±5)kJmol−1 and for PbO was ΔsubH930K0=(223±3)kJmol−1, ΔsubH298K0=(236±3)kJmol−1. The enthalpy, entropy and Gibbs energy of the following reactions were determined by 2nd and 3rd law analysis at T = 930 K:TableΔrHT0 kJ mol−1ΔrST0J mol−1 K−1ΔrGT0 kJ mol−1PbO(c) = PbO(g)223 ± 395 ± 1137 ± 4PbO(c) = Pb(g) + 0.5O2(g)312 ± 6136 ± 1186 ± 5PbO(g) = Pb(g) + 0.5O2(g)86 ± 240 ± 150 ± 2Data base dependent adaptation to 298 K are given in the tables below. Heat capacity measurements under constant pressure (Cp(T)0) by Dynamic Scanning Calorimetry (DSC) in the temperature range 298–1100 K resulted in two complex polynomial equations (see tables). The Cp(T)0 values increased to a maximum at T = about 750 K from (47.6–50.12) J mol−1 K−1 and decreases to 48.4 at the phase transition of Tc = 1006 K. Beyond the transition, Cp(T)0 becomes linear and nearly constant with ≅ 48.5 J mol−1 K−1 at 1100 K. Even the low values of entropy, ∆trsST0 = (0.045 ± 0.001) J mol−1 K−1 and enthalpy, ∆trsHT0 = (0.045 ± 0.002) kJ mol−1, and the peak shape of the phase change in the Cp(T)0 function suggest that the transition can be classified as a first order one. This phase transition was not published so far. The enthalpy and the entropy values were calculated from the Cp(T)0 polynomials and from the vaporization studies.