Search Results (54)

The combustion behavior and thermal performance of industrial-scale borax pentahydrate (Na₂B₄O₇·5H₂O) melting furnaces remain underexplored despite their critical role in boric oxide (B₂O₃) production, a key input for high-performance manufacturing. This study addressed this gap by employing three-dimensional computational fluid dynamics (CFD) simulations to model two operational natural gas-fired furnaces with distinct burner configurations (four-burner and six-burner systems). The analysis focused on optimizing burner placement, specifically, the axial distance and inclination angle, to enhance thermal uniformity and reduce refractory wall damage caused by aggressive high-temperature borate corrosion. A comprehensive parametric study of twelve burner configurations revealed that tilting the burners at 5–10° significantly improved temperature uniformity while reducing peak wall temperatures and mitigating localized hot spots. The optimal design, incorporating a 10° burner angle and a staggered burner arrangement (Case 11), attained a melt pool temperature of 1831.3 K and a charging average wall temperature of 1812.0 K. These values represent essential benchmarks for maximizing furnace efficiency and operational stability. The modified designs for the four- and six-burner systems led to improved temperature distributions and a notable reduction in maximum wall temperatures, directly contributing to longer maintenance intervals and improved refractory durability. The findings of this study confirm that minor geometrical and angular adjustments in burner placement can yield significant performance gains. The validated CFD approach and proposed design modifications offer a scalable, low-cost strategy for improving combustion efficiency and furnace lifespan in borax processing facilities. Full article

This study presents a novel ion-imprinted fiber material, I-(PP-g-GMA-NMDG), designed for the rapid and selective adsorption of borate ions. Leveraging low-temperature plasma graft polymerization, polypropylene (PP) melt-blown fibers were functionalized with glycidyl methacrylate (GMA) and N-methyl-D-glucamine (NMDG) to introduce tailored recognition sites. Systematic optimization of plasma parameters (100 W discharge power, O₂ atmosphere) and liquid-phase grafting conditions (28.5% GMA, 85 °C, 2.5 h) achieved a grafting rate of 203.26%. The imprinted fibers exhibited exceptional adsorption performance, with a maximum capacity of 35.85 mg/g at pH 9, reaching 90% saturation within 60 min. Adsorption kinetics adhered to a pseudo-second-order model, while the Freundlich isotherm indicated multilayer adsorption. Competitive ion experiments demonstrated high selectivity for B(OH)₄⁻ over anions (SO₄²⁻ and Cl⁻) and cations (Na⁺, K⁺, Ca²⁺, and Mg²⁺), which was attributed to the precise spatial and charge complementarity of the imprinted cavities. Characterization via FT-IR, XRD, and SEM confirmed successful synthesis and structural stability. The material retained 78.1% adsorption efficiency after five regeneration cycles, showcasing its practicality for boron recovery from wastewater. This work advances boron-selective adsorption technology by combining plasma modification with ion imprinting, offering a sustainable solution for industrial and environmental applications. Full article

Anode-free lithium-ion batteries offer a volumetric energy density approximately 60% higher than that of conventional lithium-ion cells. Despite this advantage, they often experience rapid capacity degradation and a limited cycle life. Optimizing electrolyte formulations—particularly through the use of specific additives, solvents, and lithium salts—is essential to improving these systems. This study explores electrolytes composed of fluorinated and carbonate-based solvents applied in anode-free lithium-ion cells featuring copper as the anode substrate and Li_1.05Ni_0.33Mn_0.33Co_0.33O₂ as the cathode. In the present work, the ionic conductivity of electrolytes was studied by impedance spectroscopy, and the electrochemical parameters of anode-free lithium-ion cells were compared using these electrolyte solutions: lithium difluoro(oxalato)borat (LIDFOB) salts were used in a mixture of solvents such as fluoroethylene carbonate (FEC) and dimethoxyethane (DME) in a ratio of 3:7 and in a mixture of propylene carbonate (PC) and dimethoxyethane in a ratio of 3:7. Enhanced performance was observed upon the substitution of conventional carbonates with fluorinated co-solvents. The findings suggest that LiDFOB is a thermostable salt, and its high conductivity contributes to the formation and stabilization of the interface of solid electrolytes. The results indicate that at low temperature conditions, a double salt should be used for lithium current sources, for example, 0.4 M LiDFOB and 0.6 M LiBF₄, as well as electrolyte additives such as fluoroethylene carbonate and lithium nitrate. Full article

The aim of this study was to investigate the possibility of Ag nanoparticle crystallization in B₂O₃–Bi₂O₃ glass using a heat treatment method and to investigate the possible influence of the obtained nanoparticles on the emission intensity of Eu³⁺ ions. Borate–bismuth glasses with different B₂O₃:Bi₂O₃ molar ratios of 50:50, 60:40 and 70:50 with Ag and Eu³⁺ ions were successfully synthesized. The structure of the glasses was studied using XRD and FTIR methods. The XRD results exhibited a characteristic amorphous halo, confirming the absence of long-range order in the samples. The glass transition temperatures of various compositions, required to select the annealing temperature, were measured using DTA analysis. The strong maximum in the UV–Vis spectrum of the sample with the highest Bi₂O₃ content clearly indicated the presence of Ag nanoparticles in the glass. Moreover, a color change was observed for this sample, from slightly yellow to red. The presence of Ag nanoparticles was further confirmed via TEM and XPS studies. However, with a high content of Ag nanoparticles in the matrix, their positive effect on luminescence intensity was not observed. The obtained results show that B₂O₃–Bi₂O₃ glass and glass ceramics, with Ag nanoparticles and rare-earth (Re) ions, could be considered as a new phosphor for light-emitting diodes (LEDs). Full article

Boron is a naturally occurring trace chemical element. High concentrations of boron in nature can adversely affect biological systems and cause severe pollution to the ecological environment. We examined a method to effectively remove boron ions from water systems using sugarcane bagasse biochar from agricultural waste with NH₃ nanobubbles (10% NH₃ and 90% N₂). We studied the effects of the boron solution concentration, pH, and adsorption time on the adsorption of boron by the modified biochar. At the same time, the possibility of using magnesium chloride and NH₃ nanobubbles to enhance the adsorption capacity of the biochar was explored. The carbonization temperature of sugarcane bagasse was investigated using thermogravimetric analysis. It was characterized using XRD, SEM, and BET analysis. The boron adsorption results showed that, under alkaline conditions above pH 9, the adsorption capacity of the positively charged modified biochar was improved under the double-layer effect of magnesium ions and NH₃ nanobubbles, because the boron existed in the form of negatively charged borate B(OH)₄⁻ anion groups. Moreover, cations on the NH₃ nanobubble could adsorb the boron. When the NH₃ nanobubbles with boron and the modified biochar with boron could coagulate each other, the boron was removed to a significant extent. Extended DLVO theory was adopted to model the interaction between the NH₃ nanobubble and modified biochar. The boron adsorption capacity was 36 mg/g at room temperature according to a Langmuir adsorption isotherm. The adsorbed boron was investigated using FT-IR and XPS analysis. The ammonia could be removed using zeolite molecular sieves and heating. Boron in an aqueous solution can be removed via adsorption with modified biochar with NH₃ nanobubbles and MgCl₂ addition. Full article

Background: Urinary tract infection is a worldwide health problem. According to the Clinical Laboratory Improvement Amendments and the European Urinalysis Guideline, urine samples should be tested within 2 h of collection. Thus, using chemical preservatives that guarantee the pre-analytical conditions is a practical tool. However, the effects of temperature and storage time as uropathogenic bacteria stressors are unclear. Methods: Gram-negative and -positive ATTC strains, E. coli, P. mirabilis, E. faecalis, and S. aureus, were used in this study. Strains in liquid media were stored at 4, 25, and 37 °C for 0, 2, 12, 24, and 48 h in tubes with and without preservatives. Then, reactive oxygen species (ROS) levels, viable but non-culturable bacteria (VBNC), and bacteria growth were analyzed. Results: A high ROS level was associated with the presence of VBNC and dead bacteria with low CFU counts, but a low ROS level increased the CFU number, depending on temperature and storage time in tubes without preservatives (boric acid, sodium borate, and formate). The BD Vacutainer™ Urine Culture & Sensitivity Preservative PLUS Plastic Tubes (C&S-PP) prevent this ROS increase, maintaining the CFU number for longer. Conclusions: C&S-PP tubes minimize the stressor effects (temperature and time storage) on uropathogenic bacteria when stored, improving the pre-analytical conditions of cultures realized by the clinical laboratory. Full article

Temperature control is important in second harmonic generation (SHG) based on non-critical phase matching, which is widely used in the accelerator field to generate drive lasers. To further improve the stability of the drive laser for the DC-SRF photocathode electron gun at Peking University, a high-precision temperature control oven for lithium borate (LBO) crystals was developed. The oven’s structure was designed to minimize heat exchange with the external environment. The temperature control circuit uses a thermoelectric cooler to ensure the temperature stability of the sampling circuit. The program utilizes a cascaded proportional-integral-derivative and an anti-saturation integral algorithm to achieve high-precision temperature control. Experiments showed that fluctuation at the working temperature of the LBO crystal in this oven was within $\pm 0.009$ °C, corresponding to a root mean square (RMS) jitter of 0.003 °C, and the long-term power fluctuation of the 13.7 W green laser generated with SHG was less than 1%. Full article

Considerable research has been conducted on single-ion conductive polymeric electrolytes with high lithium ion transference numbers. However, low ionic conductivity is a long-standing challenge for lithium metal batteries, hindering the development of extending their cycle life. In this study, we synthesized a novel fluorine-containing single-ion polymeric electrolyte, LiP(VDF-co-MAF)BB (Polyvinylidene fluoride trifluoromethyl acrylate lithium borate polymer; subsequently referred to as PPMBB), exhibiting a room temperature conductivity of 1.03 × 10⁻³ S/cm. This electrolyte demonstrates a high lithium ion transference number of 0.7901 and an extended electrochemical stability window of 5.5 V. Under a 2 C discharge rate, it manifests a remarkable discharge specific capacity of 146.8 mAh/g. Moreover, even after 364 cycles, the capacity retention remains at 76%. The single-ion polymeric gel electrolyte designed in this work provides a promising strategy for the prolonged cycling performance of lithium metal batteries. Full article

The thermal expansion of four alkaline-earth borates, namely Ca₃B₂O₆ (0D), CaB₂O₄ (1D), Sr₃B₁₄O₂₄ (2D) and CaB₄O₇ (3D), has been studied by in situ high-temperature powder X-ray diffraction (HTXRD). Strong anisotropy of thermal expansion is observed for the structures of Ca₃B₂O₆ (0D) and CaB₂O₄ (1D) built up from BO₃ triangles only; these borates exhibit maximal expansion perpendicular to the BO₃ plane, i.e., along the direction of weaker bonding in the crystal structure. Layered Sr₃B₁₄O₂₄ (2D) and framework CaB₄O₇ (3D) built up from various B–O groups expand less anisotropically. The thermal properties of the studied compounds compared to the other alkaline-earth borates are summarized depending on the selected structural characteristics like anion dimensionality, residual charge per one polyhedron (BO₃ BO₄), cationic size and charge, and structural complexity. For the first time, these dependencies are established as an average for both types of polyhedra (triangle and tetrahedron) occurring in the same structure at the same time. The most common trends identified from these studies are as follows: (i) melting temperature decreases with the dimensionality of the borate polyanion, and more precisely, as the residual charge per one polyhedron (triangle or tetrahedron) decreases; (ii) volumetric expansion decreases while the degree of anisotropy increases weakly when the residual charge decreases; (iii) both trends (i) and (ii) are most steady within borates built by triangles only, while borates built by both triangles and tetrahedra show more scattered values. Full article

To realize high-energy-density Li metal batteries at low temperatures, a new electrolyte is needed to solve the high-voltage compatibility and fast lithium-ion de-solvation process. A gel polymer electrolyte with a small-molecular-weight polymer is widely investigated by combining the merits of a solid polymer electrolyte (SPE) and liquid electrolyte (LE). Herein, we present a new gel polymer electrolyte (P-DOL) by the lithium difluoro(oxalate)borate (LiDFOB)-initiated polymerization process using 1,3-dioxolane (DOL) as a monomer solvent. The P-DOL presents excellent ionic conductivity (1.12 × 10⁻⁴ S cm⁻¹) at −20 °C, with an oxidation potential of 4.8 V. The Li‖LiCoO₂ cell stably cycled at 4.3 V under room temperature, with a discharge capacity of 130 mAh g⁻¹ at 0.5 C and a capacity retention rate of 86.4% after 50 cycles. Moreover, a high-Ni-content LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cell can steadily run for 120 cycles at −20 °C, with a capacity retention of 88.4%. The underlying mechanism of high-voltage compatibility originates from the dense and robust B- and F-rich cathode interface layer (CEI) formed at the cathode interface. Our report will shed light on the real application of Li metal batteries under all-climate conditions in the future. Full article

The development of novel photocatalysts, both visible and UV-responsive, for water decomposition reactions is of great importance. Here we focused on the application of the borates as photocatalysts in water decomposition reactions, including water splitting reaction, hydrogen evolution half-reaction, and oxygen evolution half-reaction. In addition, the rates of photocatalytic hydrogen evolution and oxygen evolution by these borate photocatalysts in different water decomposition reactions were summarized. Further, the review summarized the synthetic chemistry and structural features of existing borate photocatalysts for water decomposition reactions. Synthetic chemistry mainly includes high-temperature solid-state method, sol-gel method, precipitation method, hydrothermal method, boric acid flux method, and high-pressure method. Next, we summarized the crystal structures of the borate photocatalysts, with a particular focus on the form of the B-O unit and metal-oxygen polyhedral in the borates, and used this to classify borate photocatalysts, which are rarely mentioned in the current photocatalysis literature. Finally, we analyzed the relationship between the structural features of the borate photocatalysts and photocatalytic performance to discuss the further challenges faced by the borate photocatalysts for water decomposition reactions. Full article

Three novel anti-perovskite compounds, formulated as Cs₃X[B₁₂H₁₂] (X⁻ = [NO₃]⁻, [ClO₃]⁻, and [ClO₄]⁻), were successfully synthesized through the direct mixing of aqueous solutions containing Cs₂[B₁₂H₁₂] and CsX (X⁻: [NO₃]⁻, [ClO₃]⁻, [ClO₄]⁻), followed by isothermal evaporation. All three compounds crystallize in the orthorhombic space group Pnma, exhibiting relatively similar unit-cell parameters (e.g., Cs₃[ClO₃][B₁₂H₁₂]: a = 841.25(5) pm, b = 1070.31(6) pm, c = 1776.84(9) pm). The crystal structures were determined using single-crystal X-ray diffraction, revealing a distorted hexagonal anti-perovskite order for each. Thermal analysis indicated that the placing oxidizing anions X⁻ into the 3 Cs⁺ + [B₁₂H₁₂]²⁻ blend leads to a reduction in the thermal stability of the resulting anti-perovskites Cs₃X[B₁₂H₁₂] as compared to pure Cs₂[B₁₂H₁₂], so thermal decomposition commences at lower temperatures, ranging from 320 to 440 °C. Remarkably, the examination of the energy release through DSC studies revealed that these compounds are capable of setting free a substantial amount of energy, up to 2000 J/g, upon their structural collapse under an inert-gas atmosphere (N₂). These three compounds represent pioneering members of the first ever anti-perovskite high-energy compounds based on hydro-closo-borates. Full article

CaAl-layered double hydroxides (LDHs) exhibit different mechanisms of borate removal at varying calcination temperatures. The addition of Mg alters the structure and composition of the calcined products, ultimately impacting their adsorption process. To investigate this, CaAl-LDH and Mg-doped CaAl-LDH with and without different calcination temperatures (500 °C and 900 °C) were prepared to immobilize a wide concentration range of borate. XRD, SEM, FTIR, and EXAFS techniques were employed to study the influence of Mg doping. The results indicate that the doping of Mg increases the BET surface area and enhances the adsorption capacity of uncalcined LDHs, with the enhancement being more pronounced at high borate concentrations. For LDHs calcined at 500 °C, Mg-doped LDHs exhibited slightly better adsorption at any borate concentration due to its more favorable ettringite formation. However, for LDHs calcined at 900 °C, Mg-doped LDHs (LDO) had a slightly better adsorption effect at low borate concentrations. At high concentrations, the crystallinity and morphology of the regenerated CaMgAl-LDH deteriorated, resulting in poor adsorption effects. These findings provide valuable theoretical support for understanding the mechanisms of removing pollutants with different concentrations by different LDHs. Full article

A novel non-centrosymmetric NdSr₄O(BO₃)₃ borate and solid solutions of Nd(Ca_1−xSr_x)₄O(BO₃)₃ (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 1.0) were synthesized by solid-state reactions as well as crystallization from a melt. The crystal structures of the Nd(Ca_1−xSr_x)₄O(BO₃)₃ solid solutions with x = 0.2, 0.5 and 1.0 were determined from single crystal X-ray diffraction data and refined in the monoclinic space group Cm to R_obs = 0.028, 0.034 and 0.028, respectively. The thermal expansion of the samples with x = 0, 0.2 and 0.5 was investigated using powder high-temperature X-ray diffraction in the temperature range of 25–1000 °C. A similarity of the thermal and compositional (Ca-Sr substitution) deformations of Nd(Ca_1−xSr_x)₄O(BO₃)₃ solid solutions is revealed: Heating of Nd(Ca_0.5Sr_0.5)₄O(BO₃)₃ by 1 °C leads to the same deformations of the crystal structure as increasing the amount of Sr atoms in Nd(Ca_0.5Sr_0.5)₄O(BO₃)₃ by 0.26 at% Sr. The SHG signal of the series of Nd(Ca_1−xSr_x)₄O(BO₃)₃ solid solutions has a maximum at approximately x = 0.2. Full article

The SEM-EDX method was used to investigate the structure and morphology of organic–inorganic hybrids containing zirconium, boron and phosphorus compounds, synthesized by the sol–gel method. We started by using, for the first time together, zirconyl chloride hexa-hydrate (ZrOCl₂·6H₂O), phenyl phosphinic acid and triethyl borate as precursors and reagents, at different molar ratios. The obtained hybrids showed a very high thermal stability and are not soluble in water or in organic solvents. As a consequence, such hybrid solid materials are suitable for applications at high temperatures. The obtained hybrids have complex 3D structures and form organic–inorganic networks containing Zr-O-Zr, Zr-O-P and Zr-O-B bridges. Such organic–inorganic networks are also expected to form supramolecular structures and to have many potential applications in different fields of great interest such as catalysis, medicine, agriculture, energy storage, fuel cells, sensors, electrochemical devices and supramolecular chemistry. Full article