Ammonium Pentaborate Research Articles

Insights into impact of shock wave on structural, optical and surface characteristics of ammonium pentaborate tetrahydrate single crystal

In this study, we are emphasizing on growth of bulk size optically transparent single crystals of ammonium pentaborate tetrahydrate (APB) using the slow evaporation solution technique at room temperature. Initially, crystalline phase of the compound was confirmed through the X-ray diffraction technique. Thereafter, APB has been analysed systematically for its crystallographic structural stability in such a way that its structure has been examined periodically at two shock wave (SW) loaded conditions using XRD measurements. Further, our research contains a comprehensive knowledge about effect of shock wave on rocking curve of APB single crystal measured through high resolution XRD measurement system and the changes in crystalline perfection due to shock wave was analysed. Also, modifications in optical properties were studied due to impact of shock waves. The transmittance was checked through UV–visible spectroscopy and the changes in optical band gap were examined. The defects generated in the APB crystal after every two shocks i.e., shockwave - sample interaction was scrutinized by photoluminescence spectroscopy and surface morphology studies in detail.

One-Pot Preparation of Layered Double Hydroxide-Engineered Boric Acid Root and Application in Wastewater.

Heavy metals and organic pollutants are prevalent in water bodies, causing great damage to the environment and human beings. Hence, it is urgent to develop a kind of adsorbent with good performance. Anion interlacing layered double hydroxides (LDHs) are a promising adsorbent for the sustainable removal of heavy metal ions and dyes from wastewater. Using aluminum chloride, zinc chloride and ammonium pentaborate tetrahydrate (NH4B5O8 · 4H2O, BA) as raw materials, the LDHs complex (BA-LDHs) of B5O8- intercalation was prepared by one-step hydrothermal method. The BA-LDHs samples were characterized by a X-ray powder diffractometer (XRD), scanning electron microscope (SEM), Fourier transform infrared spectrometer (FT-IR) and the Brunauer-Emmett-Teller (BET) method. The results showed that B5O8- was successfully intercalated. Adsorption experimental results suggested that BA-LDHs possess a maximum adsorption capacity of 18.7, 57.5, 70.2, and 3.12 mg·g-1 for Cd(II), Cu(II), Cr(VI) and Methylene blue (MB) at Cs = 2 g·L-1, respectively. The adsorption experiment conforms to the Langmuir and Freundlich adsorption models, and the kinetic adsorption data are well fitted by the pseudo-second-order adsorption kinetic equation. The as-prepared BA-LDHs have potential application prospects in the removal of heavy metals and dyes in wastewater. More importantly, they also provide a strategy for preparing selective adsorbents.

The Effects of Boron-Containing Compounds against Monilinia fructigena Mycelium Growth

Monilinia fructigena is the causative agent of brown rot in pome fruits, contributing to substantial economic losses, especially in storage facilities. The effects of boron-containing compounds have been considered as an environmentally friendly alternative to fungicides. The objective of the study was to determine suitable boron-containing compounds for inhibiting the mycelium growth of M. fructigena. Eight different compounds with pH adjusted to neutral (pH 7) and non-neutral were tested with concentrations of 0 (untreated control), 5, 10, 20, 40, 60, 80, and 100 mM in vitro conditions. The mycelium growth of the pathogen was totally inhibited with the application of 20 mM of potassium tetrafluoroborate and 10 mM of sodium tetrafluoroborate. The tested concentrations of ammonium pentaborate tetrahydrate, antidot-67, sodium metaborate, and sodium tetraborate decahydrate were not sufficiently effective in inhibiting the mycelium growth of M. fructigena, but the experiment of higher concentrations of them could be utility against the pathogen. The pH of boron-containing compounds was crucial in improving the efficacy of compounds, and the non-neutral compounds showed better results against to inhibition of M. fructigena mycelium growth. The results showed that boron-containing compounds may be pathogen-specific and that the activity of these compounds is related to pH.

Multiple immobilized borate composites achieving Color-Tunable long afterglow in aqueous media for bioimaging and anti-counterfeiting

The afterglow phenomenon has garnered significant attention due to its exceptional luminescent properties, yet achieving long-lived and color-tunable afterglow in aqueous media remains a challenging task. In this article, we present a facile hydrothermal strategy for the preparation of borate afterglow materials (APB@CC) using ammonium pentaborate and cyanuric chloride as starting materials. The resultant APB@CC displays color-tunable long afterglows from blue to green in aqueous media. Further studies show that the synergistic effect of covalent and hydrogen bonds effectively promotes the immobilization and rigidification of the triplet state, enabling afterglow emission in aqueous media. Encouraged by color-tunability in solutions, we implemented their potential applications in bioimaging and anti-counterfeiting. This work not only provides insights for extending borate afterglow materials in aqueous media, but also will facilitate the development of high signal-to-noise bioimaging and advanced anti-counterfeiting techniques.

Growth and physiochemical properties of semi organic ammonium pentaborate dihydrate single crystal

Abstract The slow evaporation technique was used to produce nonlinear optical ammonium pentaborate dihydrate (APBDH) single crystals. The crystal lattice parameters and structure of APBDH crystal was determined by single crystal X-ray diffraction (S-XRD) technique with the triclinic space group. The optical band gap of the grown crystal was determined using UV–Vis spectrophotometer. There is no absorption peak was observed in the entire visible region of the spectrum. The functional groups of the APBDH crystal were identified through Fourier transforms infrared (FTIR) and Fourier transform Raman (FR-Raman) analyses. The thermal decomposition and thermal stability of the grown crystal was measured using TG-DTA analyses. The laser damage threshold (LDT) analysis was used to know the ability to withstand the influence of laser on the grown crystal. Photoconductivity of the grown crystal was studied and its photocurrent and dark current behavior was examined. The surface morphology of the APBDH crystal was evaluated using HR-SEM analysis. The APBDH crystal was exhibited second harmonic generation behavior and its efficiency was calculated with different particle sizes.

Structural, optical, antimicrobial activity and surface analysis of pure and rare earth metal lanthanum (La3+)-doped ammonium pentaborate (APB) single crystals

Structural, optical, antimicrobial activity and surface analysis of pure and rare earth metal lanthanum (La3+)-doped ammonium pentaborate (APB) single crystals

Enhanced flame retardancy level of a cotton fabric treated by an ammonium pentaborate doped silica-KH570 sol

Tetraethoxysilane (TEOS), γ- (methacryloyloxy) propyltrimethoxysilane (KH570) and ammonium pentaborate (AP, NH4B5O8) were used as a precursor, silane coupling agent and flame retardant additive to prepare a series of single (SiO2), composite (SiO2-KH570) and doped (SiO2-KH570-AP) sols via sol-gel processes. The sols were post finished to cotton fabrics through dipping-curing methods. Results show that as-prepared sol-gel systems are successfully deposited on cotton fabrics. SiO2-KH570-AP@COT shows the highest initial pyrolysis temperatures (296.4°C), char residue rate (31.5%), LOI (24.0%) and ΔLOI/Δm (4.75%/g), the most beneficial after-flame time (14.1 s) and after-glow time (0.0 s), the most complete char residue (30.0 cm), the second highest maximum pyrolysis temperature (356.6°C) and an effective synergistic effectiveness parameter (>1.0). Its flame retardancy is mainly promoted by both individually positive and jointly synergistic actions of silica sol (strong physical barrier and structural support effects in enhancing thermal stability and providing char frame), KH570 (strong coupling effect in combining components and reinforcing interface properties between components and cotton fibers) and AP (release of water molecules for cooling burning zone, diluting and isolating oxygen and gaseous products and promoting char formation). The flame-retardant treatment deteriorated the tensile strength of cotton fabrics.

Small molecule additives in multilayer polymer-clay thin films for improved heat shielding of steel

In an effort to improve the heat shielding ability of multilayer polymer-clay films, the influence of various small molecule additives was studied. Tris(hydroxymethyl)aminomethane (THAM), pentaerythritol (PER), and ammonium pentaborate (PB) are each utilized in flame retardant applications for the benefits they provide in reducing the propagation of fire. In the present study, these additives combined with polyethylenimine (PEI) and vermiculite (VMT) clay and the resulting growth of the coatings and the thermal resistivity were measured. THAM and PB salts contribute most to the overall growth of the layer-by-layer assembled films, generating an increase in film thickness of 50% or more, while PER has a greater impact on heat shielding. A 14-bilayer (THAM + PER + PEI)/VMT coating (~25 µm thick) on steel can achieve a temperature differential of over 125 °C due to a layering effect that occurs within the architecture of the macroscopic insulation bubble and disordered char. This improved thermal resistivity across a relatively thin film generates a heat shield that can be applied in novel applications such as a single-use protective barrier for aerospace components.

High performance supercapacitor electrodes based on B/N Co-doped biomass porous carbon materials by KOH activation and hydrothermal treatment

The N and B co-doped hierarchical porous carbon with excellent textured properties by using two-step of activation and hydrothermal post-treatment process using ammonium pentaborate tetrahydrate (NH4B5O8·4H2O) as both nitrogen and boron source are developed. The results showed that BNAC-3 has the maximum surface area (2471 m2/g) caused by the highest degree of micro/mesopores (0.82 and 0.35 cm3/g) and the linked 3D network are advantageous for the circulation of electrolytes and electrostatic adsorption. The contribution of Faradaic pseudocapacitance may be caused by high B (3.12 wt percent) and N (2.02 wt percent) contents of BNAC-3. Additionally, BNAC-3 exhibits excellent electrochemical efficiency with an ultra-high specific ability of 369 F/g at 1 A/g current density (CD) and maintains 240 F/g at 20 A/g in three-electrode systems. Notably, in a two-electrode device, maximum energy density can be almost 12.0 W h/kg at a power density (PD) of 375 W/kg.

Investigation on the bulk crystal growth, crystalline perfection, refractive index and piezoelectric properties of borate single crystals for piezoelectric and electro-optic applications

Low solubility potassium pentaborate tetrahydrate (KB5), ammonium pentaborate tetrahydrate (AB5) and mixed (KAB5) single crystals have been grown by the Sankaranarayanan-Ramasamy (SR) method. The crystal structures and space groups have been confirmed by powder XRD analysis. The direction of the grown crystal was confirmed by the back reflection X-ray Laue pattern. The crystalline perfection (CP) of the crystals have been evaluated using HRXRD studies. The transmittance spectra of the grown crystals were recorded by UV–Vis-NIR transmission studies showing that all the crystals have 90% transmittance in the entire visible region and found that the crystals' cut off wavelengths were below 200 nm. The optical studies such as refractive index (RI) and birefringence interferometry (BI) were reported. The RI for five different wavelengths of KB5, AB5 and KAB5 crystals were analyzed using the prism coupling method (PCM). Electromechanical behavior of the grown crystals was observed using piezoelectric coefficient (d33) measurement. Vickers Microhardness (VMH) measurement carried out at 30 °C shows increased hardness as the load increases.

Effect of borates on the synthesis of nanoscale hexagonal boron nitride by a solid-state method.

This study delves deeply into the effect of different borates (lithium tetraborate, sodium tetraborate, calcium metaborate, ammonium pentaborate) on the production and fundamental characteristic features of nanoscale hexagonal boron nitride (hBN) structure with the assistant of standard characteristic measurement methods, namely, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). The hBN samples are synthesized by reaction of powder urea, boron oxide, and different kinds of borates via the modified O'Connor method (performed at a relatively lower main heat treatment temperature of 1,100°C). All the results obtained show that the usage of borates affects positively the formation of nanoscale hBN structure. In more detail, the FTIR experiment results reveal that the presence of two strong c peaks appeared at ~1,380 and ~780 cm-1 in the spectra points out the conventional BN in-plane and out-of-plane vibrations, respectively. The XRD patterns also confirm the production of high-ordered hBN as the existence of the main peaks of the corresponding hexagonal system. As for the SEM examination, it is found that all the hBN materials exhibit totally different crystallinity quality and microstructural characteristics. The hBN compound prepared by the sodium tetraborate content shows the most uniform surface appearance with the smoothest/densest crystal structure, best grain orientations, and finest grain interactions. Hence, the material with strong stretching of interatomic bonds shows the highest material (fracture) strength. Moreover, the TEM images illustrate that all the products are composed of uniform multi-walled nanotubes and nanorods with an average length of ~250 nm.

Thermal insulation performance and char formation and degradation mechanisms of boron-containing hydrocarbon intumescent coatings

Boron compounds are effective ingredients, widely used in passive fire protection. In this work, epoxy-based hydrocarbon intumescent coatings, containing one of three boron compounds, zinc borate (ZB), ammonium pentaborate (APB), and boric acid (BA), were compared in thermal insulation performance at UL1709 heating conditions, char morphology, viscoelastic behavior, thermal degradation, and composition of the char surface layer. Results show that the char structure provides the most reliable indication of the thermal insulation performance. For APB- and BA-containing coatings, results were similar, while the ZB-containing ones showed a distinctive performance, especially the ones with the high borate concentration. The latter was attributed to the role of ZB in the intumescence and oxidation reactions, where the zinc, in the presence of boron, led to a compact char with less oxidation and high residual mass. In the char surface layer of one sample with a high concentration of ZB, a crystalline phase of boron trioxide, anticipated to be one important origin of the compact char, was detected. The present work contributes with an understanding of the essential roles of boron compounds, as well as the binder and pigment contents, and provides guidelines for seeking more sustainable and environmentally friendly alternatives.

Effect of L-Serine Doping on Growth and Properties of Ammonium Pentaborate Single Crystal

The single crystals of pure and L-serine-doped ammonium pentaborate (NH4B5O8·4H2O) (APB) are grown using the low-temperature solution growth technique. The grown crystals are 0.8–1 cm in size. The grown crystals have a retained orthorhombic structure symmetry. Spectroscopic study shows the presence of various functional groups such as N–H vibration, B–O asymmetric stretching, O–B–O ring asymmetric, C=O stretching of COOH and C–O stretching. The elemental analysis confirmed the presence of various elements. The linear optical study shows the enhancement in various optical properties such as optical transmittance, energy band gap, skin depth, etc. for APB crystal on account of L-serine doping. The a.c. electrical conductivity of APB crystal is reduced on doping the L-serine in it. The SHG efficiency of L-serine-doped APB crystals is found to be 1.10 times higher than pure APB crystal.

Effect of shock waves on enhancing the optical properties of Ammonium Pentaborate Hexahydrate single crystal molecular structure

Ammonium Pentaborate Hexahydrate (APBHH), a novel inorganic nonlinear optical single crystal was grown by slow evaporation solution growth method and the Properties of the grown crystals were investigated. The grown crystal was subjected to single crystal XRD and Powder X-ray diffraction analysis to confirm the crystal structure to the monoclinic system with centrosymmetric nature. The presence of various functional groups has been identified by using FT-IR spectral analysis ranging between 4000 and 500 cm−1. The percentage of optical absorbance was ascertained by recording the UV-Vis spectrum, crystals shows transparent in the entire visible region with a 5.56 eV optical bandgap. The dielectric constant and dielectric loss of APBHH crystal as a function of frequency and an AC resistivity, conductivity with impedance also were calculated at room temperature. Ammonium Pentaborate Hexahydrate (APBHH) crystal under pre and post shock loaded conditions. A shock wave of Mach number 1.7 was utilized for the present investigation which was generated by a table-top pressure driven shock tube. The optical properties of test material are investigated by UV-Visible spectrometer over the range between 200 and 800 nm. The observed result showed that the transparency of the crystal increase by applying Shock Waves.

Improving Weathering Performance of Wood by Borates Impregnation and Liquid Glass Coating

Weathering performance of impregnated and coated wood products is an important issue that influences their appearance as well as their service life after outdoor or indoor exposure. A novel procedure to improve the weathering performance of Scots pine wood (Pinus sylvestris L.) is proposed in this study. Wood samples were impregnated with ammonium tetrafluoroborate (ATFB), ammonium pentaborate (APB) and boric acid (BA), and afterward coated with a layer of liquid glass (LG). Surface hardness, color changes, and surface roughness of wood samples were investigated after 250 h and 500 h of exposure to artificial weathering. The results revealed that, except for untreated (control), all other treatment groups caused an increase in surface hardness of Scots pine after weathering. A decrease in the CIE L* value corresponds to the darkening of samples after weathering. Borates-impregnated and LG-coated Scots pine samples possessed the highest color stability. However, all treatment combinations resulted in reddish and yellowish tones after weathering. Exposure to weathering increased surface roughness of wood samples. The surface roughness of the untreated (control) group was higher than that of impregnated and coated samples.

Two-step synthesis of B and N co-doped porous carbon composites by microwave-assisted hydrothermal and pyrolysis process for supercapacitor application

A series of nitrogen and boron co-doped porous carbon composites (BNCs) were obtained using quick, easy and environmentally microwave-assisted hydrothermal treatment combined with a pyrolysis process subsequent. Biomass waste of fir bark is used as the carbon precursor, while ammonium pentaborate tetrahydrate is used as both boron (B) and nitrogen (N) source. The synthesis process and characteristics of the developed BNCs are investigated, and the results show that the N and B is successfully doped, generating a synergetic effect on the structure, surface characteristics and electrochemical properties. The BNCs achieves specific surface area up to 955 m2 g−1 with mainly microporosity, and possess 10–13 % of B and 15~20 % of N content. The gravimetric capacitance values for the electrodes containing BNC-20 active materials is 188 F g−1 at 0.5 A g−1, 2 times that of non-doped carbon, while maintaining 90% capacitance retention capability after 10,000 charge/discharge cycles. Furthermore, the assembled symmetric cell yielded high performance of volumetric capacitive of 91 F cm−3 at 0.5 A g−1, superior energy density of 9.33 Wh kg−1 at 400 W kg−1 with 91% capacitance retention after 10,000 charge/discharge cycles at 1 A g−1. Our work offers a potential relatively low-cost, effective and environmentally design of heteroatoms doped electrode materials with enhanced supercapacitors performance.

Ammonium pentaborate crystals with adjustable and bright phosphorescence and long lifetime

As a small molecule boron-based compound, ammonium pentaborate was prepared by a solvothermal synthesis by controlling the crystal growth process. As-prepared ammonium pentaborate crystals consisted of two perpendicular six-membered rings with powerful intermolecular interaction. A resonance hybrid of Lewis acid formed by the combination of five monovalent boric acids and coordinated with an ammonium ion. The planar six-membered ring and alternating B–O provide π-bond orbitals and anti-π* bond orbitals. The crystals exhibited a novel phosphorescence phenomenon at room temperature with excited wavelength dependence and long lifetime. Broad phosphorescence spectra show bright blue- and green-emitting excited at 250 and 360 nm while their phosphorescence lifetime is up to 1.63 and 1.49 s, respectively. The change of phosphorescence with excited wavelength is ascribed to the electronic energy level. This result provides a new idea for synthesizing new-type phosphorescent materials.

Synergistic effects of expandable graphite and ammonium pentaborate octahydrate on the flame‐retardant, thermal insulation, and mechanical properties of rigid polyurethane foam

AbstractThe use of flame retardants (FRs) to improve the flame retardancy but also having good insulation and mechanical properties of rigid polyurethane foam (RPUF) has become significant due to the increasing demand in both the industry and academia. In the present study, a series of RPUF composites containing expandable graphite (EG), ammonium pentaborate (APB) octahydrate, and their binary blends were prepared with one‐shot and free‐rise methods. The effects of FRs on the FR and physical‐mechanical properties of RPUFs were investigated. The results show that both EG and APB could improve the flame retardancy of RPUFs and reduced the smoke production. The FR effect of EG was better than APB and more importantly, synergistic effect was found between EG and APB. The best results were obtained by the foam in the composition of 15E and 5A. The cone calorimeter test results showed that the peak heat release rate (pHRR) and total smoke release (THR) of 15E/5A foam were lower than the foams of 20E and 20A. The pHRR and THR values of 15E/5A foam decreased about 57.5% and 42.8% compared to the neat RPUF, respectively. Total smoke production (m2) also reduced about 77.0% by 20E and 83.6% by 15E/5A foams. Thermogravimetric analysis indicates that the char residue of 15E/5A foam increased to 39.5%, which provided better flame retardancy. The foam composites have high compressive strength (105‐150 kPa) and low thermal conductivity values (19.9‐21.3 mW/mK). While the thermal conductivity of 15E/5A foam increased by 0.5%, its compressive strength increased by 6.1%.

Conversion of Carbon Dioxide from Air to Methanol, Formaldehyde, Formic Acid and Ammonium Pentaborate Tetrahydrate

A process for sequestering CO2 from air by sparging air through an NH4OH solution and adding NaBH4 produces formic acid, formaldehyde, methanol and ammonium pentaborate tetrahydrate in appreciable yields. This sparging chemistry centers around the well-known phenomenon of carbonate in strong bases. The newly discovered chemistry is based on H- as a nucleophile that can attack a nucleofuge, the carbonyl in carbonate in strong base. NaHCO3 was used as a positive control for the sparging method giving nearly identical IR spectra for sparged NH4OH and, NaHCO3 added NH4OH. This novel chemistry can be shown to produce H- substitution products of sulfate and phosphate esters of carbohydrates. The H- nucleophile adds one, two and three H atoms to carbonate, for formic acid, formaldehyde and methanol, respectively, two H atoms to sulfate esters and one H atom to phosphate. In this way phosphate versus sulfate substitution can be discerned by mass spectrometry using this chemistry. The pH profile of the reaction mixture for the NaHCO3 dissolved in 1 N NH4OH first dropped below starting pH possibly because the reaction vessel was capped, allowing NH3(g) to evolve and possibly drive the reaction forward. But then the pH returned to a slight lower pH than the starting pH 11.4. This novel chemistry may allow a sustainable reduction in the green-house gas, CO2, worldwide, to relieve pressure on food uses for corn and thereby avert food shortages throughout the world.

A novel method for synthesis of CaB4O7 compound using ammonium pentaborate

In this study, for the first time, α-CaB4O7 compound was synthesized using ammonium pentaborate (APB) as the source of boron. Ammonium pentaborate was prepared from a hot solution (130 °C) by a developed method. Stoichiometric solid-state reaction between CaCO3, APB and B2O3 was employed to provide a controlled pathway for the α-CaB4O7 production. Various structural analyzes were employed to characterize the produced sample. The phase formation for both APB and CaB4O7 compounds was confirmed by x-ray diffraction and Rietveld analysis. The synthesized α-CaB4O7 compound showed monoclinic structure with space group P21/n. The anionic group and bond formation was demonstrated by Raman spectroscopy. The Field emission scanning electron microscopy (FE-SEM) and Energy dispersive x-ray (EDX) analyzes were also carried out to study the morphological and stoichiometrical feature of the sample. The particle size distributions were also reported.