Effect Of Ba2 Research Articles

Effect of Ba2+ on the biomineralization of Ca2+ and Mg2+ ions induced by Bacillus licheniformis.

The effect of barium ions on the biomineralization of calcium and magnesium ions is often overlooked when utilizing microbial-induced carbonate precipitation technology for removing barium, calcium, and magnesium ions from oilfield wastewater. In this study, Bacillus licheniformis was used to bio-precipitate calcium, magnesium, and barium ions. The effects of barium ions on the physiological and biochemical characteristics of bacteria, as well as the components of extracellular polymers and mineral characteristics, were also studied in systems containing coexisting barium, calcium, and magnesium ions. The results show that the increasing concentrations of barium ions decreased pH, carbonic anhydrase activity, and concentrations of bicarbonate and carbonate ions, while it increased the contents of humic acids, proteins, polysaccharides, and DNA in extracellular polymers in the systems containing all three types of ions. With increasing concentrations of barium ions, the content of magnesium within magnesium-rich calcite and the size of minerals precipitated decreased, while the full width at half maximum of magnesium-rich calcite, the content of O-C=O and N-C=O, and the diversity of protein secondary structures in the minerals increased in systems containing all three coexisting ions. Barium ions does inhibit the precipitation of calcium and magnesium ions, but the immobilized bacteria can mitigate the inhibitory effect. The precipitation ratios of calcium, magnesium, and barium ions reached 81-94%, 68-82%, and 90-97%. This research provides insights into the formation of barium-enriched carbonate minerals and offers improvements for treating oilfield wastewater.

Effect of Ba2+ ions substitution with Sr2+ ions on the dielectric properties of Ba1− x Sr x TiO3 ceramic solid solution

The temperature dependences of the complex permittivity components ε′ and ε″ for Ba1− x Sr x TiO3 (0.1 ≤ x ≤ 0.7) solid solution obtained by two-stage ceramic technology were investigated. Both components ε′ and ε″ pass through the pronounced maxima near the Curie point. A growth of the ε′ maximum with an increase in the concentration of Sr atoms is associated with a reduction in the average grain size and an increase in the volume fraction of the intergranular layer having a lower ε′ compared to a grain. The increase in the diffusion of the phase transition with the concentration of Sr atoms is due to the greater heterogeneity of the solid solution. Based on the dielectric data, temperature dependences of the local order parameter were plotted.

BiOCl: Dy3+/Ba2+ nanophosphors: Synthesis, luminescence characteristics and applications in latent fingerprint detection and cheiloscopy

Here, we systematically investigate the structural and luminescent behaviour of Ba2+ co-doped BiOCl:Dy3+ nanophosphors synthesized by a cost-effective solid-state reaction method. The effect of Barium concentration on the structural and optical properties of Dy3+ doped BiOCl phosphors was examined in detail. The X-ray Diffraction (XRD) patterns and Rietveld refinement revealed that the as-prepared phosphors had a tetragonal crystal structure with the space group P4/nmm. X-ray Photon Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), and Raman analysis unveiled the elemental composition and vibrational modes of the prepared sample and it directly confirms the incorporation of Dy3+ and Ba2+ ions into the BiOCl lattice. The effect of Ba2+ co-doping on photoluminescence of optimized BiOCl:2%Dy3+ was studied and, observed a remarkable enhancement in the emission intensity. The decay time obtained in microseconds implied the fast-switching response of the nanophosphors. The prepared nanophosphors at optimum concentration were used for the development and visualization of latent fingerprints (LFPs) and Cheiloscopy for individual identification in forensic science. Our results reveal that the synthesized nanophosphors have potential applications in the field of color displays and may act as a valuable tool for law enforcement.

Effects of Ba2+doping on microstructure and properties of PLMNT electro-optic ceramics fabricated by hot-pressed sintering process

A series of highly transparent electro-optic (EO) ceramics Pb0.975-xBaxLa0.025(Mg1/4Nb1/2Ti1/4)0.99375O3 with the Ba2+ content of 0, 0.005, 0.01, 0.02, 0.04 were fabricated through the vacuum/oxygen hot-press sintering process. The effects of the barium substitution on the material phase transition, transmittance, dielectric, ferroelectric and electro-optic properties have been investigated and analyzed. With the Ba2+ content increasing, the shape of the ferroelectric hysteresis loop changed from rectangular to slim, the values of remnant polarization (Pr) and coercive electric field (Ec) decreased obviously. The maximum reduction of Pr can reach up to ∼89.8%. All the samples present the high transparency of ∼68% in the near infrared wavelength. The quadratic EO coefficients declines slightly while the Ba2+ content increasing. When the x is 0.01, the sample shows a relatively larger quadratic EO coefficient of ∼30.42 × 10−16 (m/V)2 and a lower Pr value of ∼2.08 μC/cm2, which promise the material a hopeful application in EO modulator.

Effect of Ba2+ ion on the structural, morphological and electrical properties of lead-free Na0.5Bi0.5TiO3 ceramics

Effect of Ba2+ ion on the structural, morphological and electrical properties of lead-free Na0.5Bi0.5TiO3 ceramics

Effect of Ba2+ doping on the properties of CeBr3 single crystal

In this work we have grown CeBr3:Ba single crystal of diameter 10 mm and length 15 mm and compared its crystal structure, luminescence and scintillation properties with pure CeBr3 crystal. It is observed that Ba2+ doping don’t change the structural properties of CeBr3 and these crystals have same hexagonal UCl3 type structure. Further, the transmission and radio luminescence spectra of Ba2+ doped and undoped CeBr3 is almost similar. The hygroscopic nature of CeBr3 is found to be remarkably reduced after Ba2+ doping. Ba2+ doping is also found to improve the scintillation performance of CeBr3 crystal by decreasing the energy resolution though there is a slight increase in the decay time of CeBr3. The energy resolution for 0.1 mol% Ba2+ doped CeBr3 is 4.46% as compared to 4.7% for pure CeBr3 crystal.

Effects of Ba2+Doping on Microstructure and Properties of Plmnt Electro-Optic Ceramics Fabricated by Hot-Pressed Sintering Process

Effects of Ba2+Doping on Microstructure and Properties of Plmnt Electro-Optic Ceramics Fabricated by Hot-Pressed Sintering Process

Effects of Ba2+/Sr2+ ratio on the microstructure, dielectric and ferroelectric properties of Ba x Sr(1−x)TiO3 films prepared by micro-arc oxidation

ABSTRACT BaxSr(1-x)TiO3 (BST) thin films are in situ deposited on a Ti matrix through the micro-arc oxidation technique, using a mixed aqueous solution of Ba(OH)2•8H2O, Sr(OH)2•8H2O and 0.05 M EDTA as the electrolyte. The influence of the Ba2+/Sr2+ ratio on the phase composition, microstructure and properties of the BST thin films is investigated. Ba0.6Sr0.4TiO3, Ba0.5Sr0.5TiO3, and Ba0.4Sr0.6TiO3 thin films have a cubic phase, while Ba0.8Sr0.2TiO3 and Ba0.7Sr0.3TiO3 thin films have a tetragonal phase. When the concentration of Ba2+ in the electrolyte surpasses that of Sr2+, the width of micro-arc holes and the surface roughness of the film grow as the Ba2+ concentration rises. Furthermore, the dielectric and ferroelectric properties of BST films are favorably connected with the surface morphology. When the Ba2+ concentration is 0.06 M, the film has the best compactness and smoothness. In addition, the highest capacitance and lowest dielectric loss are achieved.

Electrochemically Dismantled Perovskite with Cooperative Catalysis for CO2-to-Formate Conversion

Electrochemical reduction of carbon dioxide (CO2RR) driven by sustainable energy resources holds great promise for realizing the zero net emission of CO2 by converting them to value-added fuels.1–4 For the past few years, substantial efforts have been devoted to boosting CO2RR using different nanostructured catalysts. However, the complicated synthesis procedures and low product yields are usually associated with many of these catalysts, which hinder their scalability. More importantly, many catalysts suffer from the low catalytic activities, high overpotentials, and unsatisfactory selectivity, which collectively impede the large-scale applications of CO2RR technique. In this study, we pursue initiating the CO2 conversion on perovskite-based catalysts BaBiO3 (BBO) to selectively produce formate (FA). The structural/phase evolution of BBO under cathodic potentials, the catalytic performances of electrochemical and photoelectrochemical reduction of CO2RR, and the effect of non-active A-site element (Ba) will be investigated in detail.Herein, BBO perovskite is fabricated by annealing the sol-gel Ba2+/Bi3+ nitrate mixture at high temperatures. Extensive physical characterizations show that under negative potentials, BBO pre-catalysts undergo irreversible structural and phase transformations, giving rise to Bi metallene with atomic-scale thickness and enlarged surface area, as supported by X-ray diffraction analysis and transmission electron microscopy (Figure 1a, and 1b). Using the fully electrochemically reduced BBO, a near-unity selectivity towards formate (FA) can be achieved at the potential of – 1.2 V vs. RHE in 0.1M KHCO3 solution with the typical H-type electrochemical cell. By coupling the state-of-the-art BiVO3 photoanode to the BBO dark cathode, FA can be generated at a of 80.0 % at a cell voltage of 2.5 V in a PEC cell. Contrarily, only < 1.0 % can be detected at 2.5 V without solar irradiation. Meanwhile, inductively coupled plasma optical emission spectrometry (ICP-OES) analysis suggests that A-site elements (Ba2+) are simultaneously released from the BBO lattice and diffuse to the electrolyte as a result of the complete reduction of BBO. The effect of Ba2+ - containing electrolytes on the CO2RR product distributions have been studied, and the results show that Ba2+ can either facilitate or impede FA production depending on both the external potential and the concentration of Ba2+ (Figure 1c). Specifically, high Ba2+ concentration and more negative potentials (i.e., 25 mM Ba2+ and -1.1 - -1.3 V vs. RHE) tend to favor HER over CO2RR due to the formation of BaCO3 precipitates, whereas low Ba2+ concentrations and more positive potentials (i.e., 2.5 and 7.5 mM Ba2+ and -0.9 - -1.1 V vs. RHE) can significantly enhance the selectivity towards FA. Density functional theory (DFT) calculations show that suitable barium ion adsorption promotes CO2-to-FA conversion by regulating the adsorption strength of *OCHO and *HCOOH intermediates. Our study utilizes both A- and B- site elements in BBO to benefit CO2 conversion, which may be extended to other perovskite electrocatalysts for CO2RR.

The effects of Ba2+ addition in the LiCO3–Mn2O3–B2O3 glass structure on electro-chemical and physical characterizations

The effects of Ba2+ addition in the LiCO3–Mn2O3–B2O3 glass structure on electro-chemical and physical characterizations

Effect of Ba2+ doping on the structure and transport properties of Li6.28Al0.24La3Zr2O12 solid electrolyte

Effect of Ba2+ doping on the structure and transport properties of Li6.28Al0.24La3Zr2O12 solid electrolyte

Influence of A-site doping barium on structure, magnetic and microwave absorption properties of LaFeO3 ceramics powders

In this paper, the effect of Ba2+ ions A-site doping LaFeO3 on structure, magnetic properties and microwave absorption properties was investigated by the sol–gel method. According to the TEM and FullProf refinement results, the structure of LaFeO3 changes from orthogonal (SG: Pnma) to cubic (SG: Pm-3m) when the Ba doping amount is x = 0.4. The SEM image shows that the particles size tends to decrease with the increase of Ba content. The production of weak ferromagnetism indicates that Ba doping has a significant effect on the magnetic properties of LaFeO3. The Neel temperature (TN) decreases significantly with the increase of Ba doping amount. An appropriate amount of Ba doping can effectively increase the dielectric and magnetic loss of LaFeO3 ceramics powders. The increase permittivity (ε′ and ε″) may be attributed to the hopping of the electrons between the Fe3+ and Fe4+ ions with the Ba2+ ions doping. The minimum reflection loss (RLmin) of La0.9Ba0.1FeO3 at 6.72 GHz reaches −30.04 dB, its effective bandwidth (RL ≤ −10 dB) is 2.1 GHz, and the matching thickness is only 3.2 mm. These results indicate that Ba doping can effectively control the microwave absorption properties of LaFeO3, especially in the C-band.

Effect of Barium Addition on Hydrolytic Enzymatic Activities in Food Waste Degradation under Anaerobic Conditions

Enzymatic hydrolysis of complex components of residual materials, such as food waste, is a rate-limiting step that conditionates the production rate of biofuels. Research into the anaerobic degradation of cellulose and starch, which are abundant components in organic waste, could contribute to optimize biofuels production processes. In this work, a lab-scale anaerobic semi-continuous hydrolytic reactor was operated for 171 days using food waste as feedstock; the effect of Ba2+ dosage over the activity of five hydrolytic enzymes was also evaluated. No significant effects were observed on the global performance of the hydrolytic process during the steady-state of the operation of the reactor, nevertheless, it was detected that Ba2+ promoted β-amylases activity by 76%, inhibited endoglucanases and α-amylases activity by 39 and 20%, respectively, and had no effect on β-glucosidases and glucoamylases activity. The mechanisms that rule the observed enzymatic activity changes remain unknown; however, the discussion in this paper provides hypothetical explanations for further research.

Effect of Ba2+ doping on the photoluminescence of YVO4: Eu3+ phosphor and first principles calculations

In this work, YVO4: Eu3+ phosphors with and without Ba2+ doping (having the formula of Y1-x-y (EuxBay)VO4) were prepared by the high-temperature solid-state reaction method, and their photoluminescence and relevant physical mechanism were studied. A large enhancement in the photoluminescence of the YVO4: Eu3+ phosphors by Ba2+ doping has been observed. When the Ba2+ doping concentration is at 3 at%, the YVO4: Eu3+ phosphors have the strongest photoluminescence. It has been found that the Ba2+ doping extends the luminescence decay lifetimes of YVO4: Eu3+. In addition, the Ba2+ doping also makes the charge transfer state absorption band of VO43− blue shifted and widens the 5D0→7F2 emission of Eu3+. The underlying mechanism for these results has been investigated using the first principles calculations. It has been shown that the Ba2+ doping increases the bandgap value of YVO4 and causes the energy level of the Eu-d orbit to split, and the individual atomic orbitals move toward higher energy after Ba2+ doping. A higher energy transfer efficiency from VO43− to Eu3+ has been predicted by the first principles calculations. The theoretical calculation results explain the photoluminescence enhancement of YVO4: Eu3+ by Ba2+ doping, and the mechanism has been revealed.

The Influence of Ba2+ Ions on the Physical Properties of Perovskite Nanoparticles La1−xBaxFeO3 Synthesized by Sol–Gel Method

The sol–gel autocombustion preparation is used to synthesize La1–xBaxFeO3 (x = 0–0.25) nanoparticles, and the effect of Ba2+ doping amount is investigated. For the purpose of analysis, it is found that the perovskite orthorhombic structure of LaFeO3 did not change with increasing doping amounts of Ba2+ ions. The space group is still Pnma (62). The X‐ray diffraction (XRD) spectra show the BaCO3 second phase when x ≥ 0.15. In addition, Fourier‐transform infrared (FT‐IR) confirms the antisymmetric stretching vibration in the Fe–O–Fe bond of the octahedron FeO6. Furthermore, vibrating sample magnetometer measurements show that the amount of Ba2+ dopants can improve the magnetic properties of the sample. The magnetic properties of the samples can also be greatly influenced by the calcination temperature.

Structural, magnetic and catalytic properties of La2-xBaxCuO4 (0 ≤ x ≤ 0.5) perovskite nanoparticles

Barium doped La2CuO4 perovskite nanoparticles were synthesized via microwave assisted combustion method. The effects of Ba2+ doping on structural, optical, magnetic and catalytic activity of La2CuO4 have been studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) and vibrating sample magnetometer (VSM) techniques. The XRD patterns of pure La2CuO4 and La1.9Ba0.1CuO4 confirmed the formation of perovskite structure without impurities. However, with increasing Ba2+ content in the range 0.2–0.5, phase transformation from orthorhombic to tetragonal structure, occurred. The average crystallite size of orthorhombic and tetragonal phases were in the range 45.2–52.2 nm and 0.5–41 nm, respectively. The appearance of FT-IR bands at around 685 and 517 cm−1 were correlated to the La-O and Cu-O stretching modes of orthorhombic La2CuO4 phase. The direct band gap estimated using Kubelka–Munk (K–M) method decreased with the increase in Ba2+ content (1.88–1.64 eV), due to the formation of sub-bands in the energy band gap. Magnetic measurements of doped La2CuO4 samples showed either para- or ferro-/para- magnetic behaviour at room temperature. The catalytic activity (oxidation) tests carried out in a batch reactor operating under atmospheric conditions indicated that the prepared catalysts, in particular (La1.7Ba0.3CuO4), showed excellent catalytic activity.

Structural changes and magnetism in Bi1−xBa x FeO3 (x = 0, 0.1, 0.2, 0.3) nanopowders

Bi1−xBa x FeO3 (x = 0, 0.1, 0.2 and 0.3) ceramic nanopowders were prepared by the ethylene glycol-based sol–gel method followed by heat treatment at 800 °C for 1 h. The effect of Ba2+ ions substitution on the structural and magnetic properties of the BiFeO3 (BFO) has been investigated. X-ray diffraction along with Rietveld refinement of Ba-substituted samples showed the presence of both rhombohedral (R3c) and pseudocubic (Pm3m) phases. Microstructural analysis confirmed the formation of homogeneous and nearly cubic nanoparticles. Result shows a reasonable enhancement in saturation magnetization of the substituted samples. Bi0.9Ba0.1FeO3 having 30% R3c and 70% Pm3m phases, show maximum saturation magnetization, i.e., 0.32 emu/g at room temperature. The magnetic properties of synthesized ceramics have been discussed in terms of FeO6 octahedra tilting with respect to body diagonal of the pseudocubic system. By combining magnetic measurements with thermal analysis, it is shown that the substitution of Ba for Bi site causes an enhancement in magnetic transition temperature (TN).

Enhanced Photocatalytic Activity in Bi1-xBa x FeO3 Prepared by a PEG400 Assisted Sol–Gel Method

Ferroelectric Bi1-xBa x FeO3 nanoparticles for x = 0, 0.01, 0.03, 0.05 and 0.10 were synthesized by a polyethylene glycol 400 (PEG400) assisted sol–gel method. X-ray diffraction reveals that Bi1-xBa x FeO3 nanoparticles exhibit a distorted rhombohedral structure with the R3c space group, and the diffraction peaks shift upon incorporation of Ba. Transmission electron microscope analysis shows that the particle size of Bi1-xBa x FeO3 nanoparticles is in the range of 30–60 nm, decreasing with an increase in Ba content. Bi1-xBa x FeO3 nanoparticles have band gaps in the range of 1.68–2.0 eV, which are capable of responding to visible light irradiation. The rate of the photocatalytic degradation of Bi1-xBa x FeO3 nanoparticles for x = 0.03 to methyl orange (MO) dye achieves about 81% under visible light irradiation for 3 h, which is higher than that of 66% for pure phase BiFeO3 (BFO). Moreover, the effects of Ba2+ modification on the band gap of BFO crystallites have been investigated and discussed.

Microwave dielectric properties of barium substituted screen printed CaBi2Nb2O9 ceramic thick films

In the present study, Aurivillius-structured Ba2+ substituted CaBi2Nb2O9 (CBNO) ceramic powder was synthesized by co-precipitation method. The CBNO thick films were delineated by screen printing method on alumina substrates using co-precipitated ceramic powder. The overlay method was adopted to measure the microwave dielectric properties of prepared thick films. Single phase layered perovskite structure of the prepared thick films was confirmed by X-ray Diffraction. The effects of Ba2+ substitution on the surface morphology, bonding, and microwave dielectric properties of thick films were systematically presented. The maximum value of microwave dielectric constant for the CBNO thick films at 11.8GHz is 15.6 for Ba2+=0.8 substitution. The shift in the stretching vibration modes of the Nb-O bond of NbO6 octahedron in the Raman spectra with a substitution of Ba2+ in CBNO was observed. The substitution of Ba2+ on A-site of CBNO improves the microwave dielectric properties of prepared thick films. This work may provide a new approach to enhance the microwave dielectric performance of Aurivillius-structured ceramic thick films.

Homogeneous precipitation synthesis of BaCO3 powders with a needle-like morphology

Abstract Barium chloride dihydrate, sodium hydroxide and carbamide were used to prepare barium carbonate (BaCO3) powders using the homogeneous precipitation method. The effects of Ba2+ concentration, (NH2)2CO concentration, NaOH concentration, reaction temperature and reaction time on the particle size and yield of product were mainly researched. The structure and the thermal stability of BaCO3 powders prepared were analyzed using scanning electron microscopy (SEM) and thermogravimetry-differential scanning calorimetry (TG-DSC), respectively. The particle size distribution of BaCO3 powders was also characterized using a laser particle size analyzer. The results showed that the BaCO3 powder prepared has high purity with a needle-like morphology. Based on the results mentioned, this method can be applied in an effective and efficient way for BaCO3 powder preparation.