Ammonium Bromide Solution Research Articles

Hydration number and allied parameters of aqueous solutions of ammonium bromide through ultrasonic study

Hydration number and allied parameters of aqueous solutions of ammonium bromide through ultrasonic study

Multi‐step heating strategy during thermal stabilization of polyacrylonitrile multi‐filament bundle before carbonization

AbstractA polyacrylonitrile (PAN) multi‐filament bundle underwent a multi‐step heat treatment following impregnation with a solution of ammonium bromide, phosphoric acid and urea (A‐P‐U). The multi‐step thermal stabilization process was conducted in an air atmosphere at temperatures ranging from 200 to 245 °C for various stabilization times spanning from 10 to 70 min. Comprehensive analysis of physical and mechanical properties, infrared (IR) spectroscopy, X‐ray diffraction (XRD) and thermal analysis (DSC and TGA) revealed the significant influence of stabilization time on the structure and properties of thermally stabilized PAN multi‐filament bundle. The fiber thickness and linear density of the stabilized fibers decreased by approximately 29.5% and 10.6%, respectively, after 70 min of heat treatment. However, the fiber density value increased from 1.18 to 1.38 g cm−3 during the same stabilization time. Additionally, the carbon yield value obtained using TGA increased from 31% to 73% at 850 °C. The presence of A‐P‐U markedly reduced the time needed for the conversion of the PAN polymer into a cyclized structure through its nitrile groups, thereby accelerating the stabilization reactions. Furthermore, the IR spectra exhibited the appearance of CC bonds, signaling the creation of a crosslinked ladder‐like structure. The XRD traces confirmed the decrease in crystallinity with increasing stabilization time, consistent with the findings from IR spectra. The findings showed that the A‐P‐U integrated system is notably successful and proficient in promoting the cyclization of nitrile groups, thereby decreasing the time needed to establish a thermally stable structure capable of withstanding elevated carbonization temperatures. © 2024 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of surfactant on dynamics and gas-liquid mass transfer for single carbon dioxide bubbles

In carbonation reaction, the impact of surfactants on the movement and mass transfer behavior of carbon dioxide bubbles were crucial for the production of high-quality silicon dioxide products. The study employed the Matlab image processing system to investigate the shapes, motion velocities, and rise path of single carbon dioxide bubbles within varying concentrations of cetyltrimethyl ammonium bromide (CTAB) solutions. This exploration aimed to elucidate the effect of CTAB on the movement and mass transfer coefficient (MTRC) of single carbon dioxide bubbles. Alterations in the CTAB solution concentration and bubble sizes significantly influenced the mass transfer and movement characteristics of single carbon dioxide bubbles. The conclusion was drawn through the computation of the MTRC of single carbon dioxide bubbles in deionized water and CTAB solutions: the addition of CTAB significantly reduced the mass transfer efficiency of carbon dioxide in deionized water, with the MTRC of CTAB solutions decreasing as the solution concentration increased. Utilizing the stagnant cap model, it can be concluded that CTAB's reduction of the MTRC of carbon dioxide was attributed to the high viscosity of the medium, low bubble velocity, stable flow conditions, and intensified adsorption degree of CTAB molecules at the gas-liquid interface. According to the significant periodic trajectories of single carbon dioxide bubbles in the stable range, the correlation between the trajectories of compressible bubbles in surfactant solution and mass transfer in liquid phase was established, and the previous method based on rigid sphere model was modified. The paper proposed the mechanism of CTAB's influence on single carbon dioxide bubbles, offering crucial theoretical insights into the industrial application of surfactants in the carbonation process for producing silicon dioxide.

A comprehensive study on the effect of rock corrosion and CO2 on oil-water interfacial tension during CO2 injection in heavy oil reservoirs

This study is focused on addressing issues related to the interaction mechanism between reservoir rocks and fluids during CO2 injection in heavy oil reservoirs. The results indicate that the carbonated water formed after high-pressure CO2 injection is causing corrosion in the core structure. Furthermore, the average corrosion rate increases from 0.358% as pressure increases from 8 MPa to 16 MPa to 0.742%. The core slices exhibit corrosion pits and cracks on their surface, as well as surface particles flaking and dissolving. The dynamic IFT between decyl trimethyl ammonium bromide solution and crude oil exhibited slower stabilization and less change without CO2 injection. However, with increasing pressure post CO2 injection, the dynamic IFT decreased at a more rapid rate. Furthermore, positive correlation between equilibrium IFT and temperature was observed with low-pressure CO2. In contrast, the surfactant played a more dominant role in reducing IFT with high-pressure CO2. The findings of this study can help for better understanding of the mechanism of microscopic action on reservoir rock and oil-water interface after CO2 injection, and offer theoretical basis and reference for CO2 injection in heavy oil reservoirs to enhance the recovery rate.

Adsorption of Glyphosate by Palygorskite

Glyphosate affects ecosystems due to exposure of non-target crops and is a persistent contaminant at low concentrations. The application of palygorskite to reduce glyphosate contamination in Brazil is an environmentally friendly way to remediate impacted areas. This research evaluated palygorskite application for glyphosate adsorption present in a synthetic effluent. Palygorskite samples were ore dressed by wet granulometric classification and wet magnetic separation and submitted to organophilization with cetyltrimethyl ammonium bromide solutions at concentrations of 0.01, 0.1, 1.0 and 1.5% (w/w), and the organo-palygorskite was applied in glyphosate adsorption tests. After ore dressing there was an increase in its cation exchange capacity from 19 to 41 meq 100 g-1 and the surface area was 149 g m-2. The 1.0% organo-palygorskite adsorbed about 86% of glyphosate from synthetic aqueous effluent. Based on this high adsorption yield, the organo-palygorskite is a potential adsorbent for remediation of effluents containing the toxic herbicide glyphosate.

Self-Assembly of Nanocrystals into Ring-like Superstructures: When Shape, Size, and Material Do Not Matter.

This manuscript describes a universal method for the spontaneous self-assembly of nanostructures ranging from 2-4 nm spherical particles to ∼440 nm long anisotropic nanorods into ring-like superstructures. The nanostructures composed of Au, Pt, and Pd as surface materials were synthesized in an aqueous cetyltrimethyl ammonium bromide (CTAB) solution. The ligand exchange technique with 4-mercaptophenol was applied to replace CTAB from the surface of nanostructures with a functional thiol. The esterification reaction was carried out to covalently attach carboxy-terminated long-chain polystyrene (PS) molecules to the surface of nanostructures. The high grafting density of PS chains around nanocrystals made them highly soluble in a wide range of organic solvents. When a drop of nanostructure solution in a volatile nonpolar solvent was dried on a solid surface, the nanostructures spontaneously arranged themselves in the form of ring-like assemblies. The condensation of microscopic water droplets from the atmosphere on the surface of an evaporating solvent creates templates for the self-assembly of nanostructures into rings. We demonstrate that this self-assembly method is highly universal and can be extended to various nanostructures regardless of their shapes, sizes, and surface materials.

Facilitate hole transport with thin 2D perovskite capping layer to passivate interface defects of 3D perovskite solar cells using PEABr

Hybrid 2D/3D-perovskites are attracting more interest in the area of organometal halide perovskite solar cells (PSCs) because of their high efficiency and extended environmental stability. The 3D portion in 2D/3D perovskites, serves as an active material with exceptional optoelectronic characteristics (for example excellent light absorption and an extended carrier lifetime), while its 2D counterpart protects against environmental conditions (water and oxygen) and increase the stability of the whole structure. In this study, a hetero-structure 2D/3D is constructed via spin-coating a phenyl-ethyl ammonium bromide (PEABr) solution upon over of (FA0.6MA0.4)PbI3 3D perovskite films. As compared to their 3D analogs, the PSC devices based on optimized 2D/3D hetero-structures display substantial improvements in photovoltaic efficiency due to the passivation of cationic and halide vacancies on the surface of 3D perovskite for better energy level alignments, longer carrier lifetimes, and fewer defects, which facilitate hole transfer and transport to the hole transport layer and reduce interface recombination centers. The extremely-thin film of 2D perovskite on the top of 3D perovskite boots the stability and reduces the crystal imperfection of 3D perovskite. Furthermore, the PEABr-treated perovskite device has a PCE of 20.57% as compared with the control device, which has a PCE of 17.01%.

Research on preparation and filtering effects of modified talc filter aid

To reduce the shortcomings of existing filtering assistance, the talc was modified by a two-step method. In the first step, the talcum powder was heated by microwave in the acid solution. In the second step, the talcum powder was stirred with Hexadecyl Trimethyl Ammonium Bromide (HTAB) solution for optimum time under an optimum temperature. The optimum temperature, time and amount of HTAB were investigated by the batch membrane filtration experiments of kaolin suspension. The filtering effects of the new talc filter aid were evaluated with the filtration rate and moisture content in filter cake. The results showed that the optimum conditions were: the amount of 0.05 mmol/L HTAB was 100 ml, the modified temperature was 80℃ and the modified time was 60 min. When the filtrate was accumulated to 25 ml, the filtration time was 13.21 s shorter than others. The membrane flux of microfiltration was the largest (0.024 L/m2·s) when new talc filter aid was added into the kaolin suspension. The talc powder was characterized by Fourier Transform Infrared Spectroscopy and X-ray diffraction, which made the experimental results more obvious. Characterization results indicated that the hydrophobicity of the talc filter aid was excellent because microwave-assisted acidification talcum powder could absorb the cationic surfactants by electrostatic interactions. Finally, by comparing talc filtration assist with diatomite filtration assist, it is concluded that the filtration performance of talc filtration assist kaolin suspension is superior to other materials.

A novel porous polymeric microsphere for the selective adsorption and isolation of conalbumin

Porous polymeric microspheres, poly(styrene-divinyl benzene, PSDVB)-poly(ethylene glycol monoallyl ether, PEGMAE), termed as PSDVB-PEGMAE, are prepared via double emulsion interfacial polymerization strategy. PSDVB-PEGMAE microspheres exhibit a mean diameter of 2.98 μm, and possess heterogeneous porous structure with a pore volume of 0.354 cm3 g−1 and a pore size of 34.3 nm. PEGMAE moiety is identified on the external surface of the microspheres, while both PSDVB and PEGMAE moieties are found in the interior pores. The PSDVB-PEGMAE microspheres possess favorable selectivity towards the adsorption of conalbumin (ConA) through hydrogen-bonding and hydrophobic interactions, via surface and inter-pore adsorption. At pH 6, an adsorption capacity of 171.9 mg g−1 is achieved for ConA. The captured ConA may be readily recovered by stripping with a cetane trimethyl ammonium bromide (CTAB) solution (0.1%, m/v). The microspheres are further used for the isolation of ConA from egg white, deriving high purity ConA as demonstrated by SDS-PAGE assay.

Extraction and determination of flavonoids in fruit juices and vegetables using Fe3 O4 /SiO2 magnetic nanoparticles modified with mixed hemi/ad-micelle cetyltrimethylammonium bromide and high performance liquid chromatography.

Extraction and determination of three flavonoids (morin, quercetin, and kaempferol) were performed by dispersive magnetic solid phase extraction based on mixed hemi/ad-micelles and high-performance liquid chromatography with UV detection. The Fe3 O4 /SiO2 nanoparticles were synthesized and characterized by X-ray diffraction, FTIR, scanning electron microscopy, and thermogravimetric analysis. Fe3 O4 /SiO2 nanoparticles coated with mixed hemi/ad-micelles cetyltrimethyl ammonium bromide was applied as a sorbent and used for extraction of flavonoids. Effective parameters on the extraction recovery such as amount of magnetic nano particles, volume of cetyltrimethyl ammonium bromide solution with specific concentration, pH of sample solution, adsorption equilibrium time, volume of desorption solvent, and desorption times were evaluated and optimized using fractional factorial design and central composite design. Under the optimum condition limit of detection and linearity were 0.83, 2.7-500.0 for morin, 0.18, 0.7-500.0 for quercetin and, 0.37, 1.3-500.0 µg/L for kaempferol. The extraction recovery with relative standard deviation were 97.88, 1.94 for morin, 95.77, 0.80 for quercetin, and 93.35, 1.45 for kaempferol. The proposed method was applied for simultaneous extraction and determination of flavonoids in several fruit juices and vegetable samples.

Synergistic Rheological Behavior of Mixed Micellar Solutions of Surfactin and Cetyl Trimethyl Ammonium Bromide

AbstractThis paper investigated the rheological properties of novel viscoelastic thickening micelle system formed by surfactin and cetyl trimethyl ammonium bromide (CTAB). The total concentration of surfactin and CTAB was maintained at 12 wt%. The rheological behavior of the surfactin/CTAB synergistic micelles with different mass ratio and pH was systematically investigated. For the surfactin/CTAB micellar system with a mass ratio varied from 1/11 to 4/8, the viscosity of the micelles rose to a maximum with increasing pH, and then decreased with a further increase of pH. When the mass ratio was surfactin:CTAB = 2.5:9.5 (pH 5.72), the maximum viscosity of the micelle solution reached 8170 mPa. s. Meanwhile, the viscosity curve of the surfactin/CTAB systems was described by the nonlinear co‐rotational Jeffreys model. This work sets a rheological foundation for the application of surfactin/CTAB systems. The thixotropic loop area of the micelles was basically zero. Through viscoelasticity measurements, the results demonstrated that the appropriate surfactin/CTAB mass ratio would favor the stability of the network structure of the synergistic thickening system. The value of G″(viscous modulus) is always higher than the value of G′ (elastic modulus).

Influence of different solvents on the growth, thermal and dielectric properties of Phthalic acid single crystals

ABSTRACT Good quality Phthalic acid single crystals were grown in aqueous solutions of ammonium oxalate and ammonium bromide by slow evaporation solution growth method. Single crystal X-ray diffraction of PA1 and PA2 was analysed in this article. The functional groups of crystals were identified and confirmed by FT-IR analysis. UV-Vis absorption spectrum was analysed, which shows that least absorbance in the entire visible region and the value of an optical band gap was determined. The second harmonic generation efficiency of the crystals was determined by Kurtz’s powder method, which confirms non-linear optical property of the title material. The thermal stability and melting point of PA1 and PA2 crystals were found by the TGA and DTA thermal analysis. The kinetic parameters were calculated using Coats and Redfern method. The dielectric study was carried out by determining dielectric constant, dielectric loss and ac conductivity using LCR metre and the variation of these parameters with frequency and temperature was analysed.

Polyurethane/Bentonite/Chitosan Blend for Improved Thermal and Protection Microorganisms for Paint Application

In this study polyurethane synthesis was carried out using the pre-polymer method using the reaction of Toulena Diisocyanate (TDI) with oleic acid-based palm oil polyols. To provide heat resistance properties for coating paint material, add bentonite (B) and chitosan (K) to polyurethane samples. The concentrations of bentonite and chitosan used were 1% b / b, 2% b / b and 3% b / b, respectively. Palm oil-based oleic acid polyol samples were analyzed for chemical compound structure using Fourier Transform Infrared (FTIR) obtained by O-H group at a wavelength of 3437.15 cm-1. Preparation of bentonite and chitosan purification was done by adding cetyltrimethyl ammonium bromide solution to bentonite solution and CH3 3 COOH 2% solution and NaOH into chitosan solution, successfully increasing the d-spacing layer with the acquisition of 1.144 nm to 1.513 nm in bentonite and 1.117 nm to 1.475 nm in chitosan and an increase in the value of heat resistance is evidenced by the results of observations using XRD and Thermogravimetric Analysis (TGA).

Molecular dynamics simulation of spherical-to -threadlike micelle transition in a cationic surfactant solution

ABSTRACTThe effect of sodium salicylate (NaSal) on the spherical-to-threadlike micelle shape transition in 3-hexadecyloxy-2-hydroxy-propyl trimethyl ammonium bromide (R16HTAB) solution was studied using molecular dynamics simulation. The simulations were started from a preassembled infinitely long threadlike micelle of R16HTAB. By analyzing the aggregation morphologies and structural details, we find that the preassembled threadlike micelle in the absence of NaSal was unstable and assembled into a spherical micelle. While in the presence of NaSal, the threadlike micelle exhibited fluctuations but remained the threadlike shape during the long simulation run. The Sal− ions were found to penetrate inside the micelle, which promoted the junction between the surfactant and salicylate counterion. The aromatic Sal− ions located in the surfactant headgroup region with their phenyl groups pointing toward the interior core region of the micelle. From another simulation started with two individual spherical micelles, we found that the Sal− ions can link the two spherical micelles into a long threadlike micelle, in accordance with a mode proposed by experimental studies. Our studies showed that the H-bonds and electrostatic interactions between the Sal− ions and the surfactants played an important role in micellar growth and stabilising the threadlike micelle.

Photoreaction of 9,10-Anthraquinone-2,6-disulfonic Acid and Ascorbic Acid Complexed at the Cationic Bilayer Interface and Consecutive Radical Dynamics

The antioxidant ability of substances such as vitamin C has attracted wide attention, and many antioxidant effects on our body are considered to act in the biomembrane interface region. However, the detailed dynamics of the radicals at the interface have not been deeply clarified. Here, we studied the reaction of photoexcited 9,10-anthraquinone-2,6-disulfonic acid dianion (AQDS2–) and ascorbic acid in the cationic vesicle solution of didodecyldimethyl ammonium bromide using time-resolved electron paramagnetic resonance (TR-EPR) and UV–vis absorption methods. The results were compared with those of micellar and aqueous systems. Analysis of UV–vis spectra revealed the formation of an intermolecular charge-transfer complex of ascorbic acid monoanion (AscH–) and AQDS2– at the cationic bilayer interface. The TR-EPR spectra revealed a hydrogen atom abstraction reaction by the excited triplet state of AQDS2– from AscH– to form an ascorbic acid monoanion radical (Asc•–) and an anthrasemiquinone dianion radical (A...

Preparation and performance of form-stable TBAB hydrate/SiO2 composite PCM for cold energy storage

Combining cold energy storage using phase change materials (PCMs) with cooling system used in air conditioner can make notable improvement in energy conservation. In this research, 40% tetra-n-butyl ammonium bromide (TBAB) solution as cold energy medium was preferred due to its appropriate phase change temperature (11.81 °C) and high latent heat (211.9 J g−1). Additionally, Na2HPO4·12H2O as nucleating agent could minimize its supercooling degree, with the enhanced crystallization behavior confirmed by optical microscope. A form-stable TBAB hydrate/fumed silica (SiO2) composite PCM was prepared and characterized. The results indicated that the composite PCM containing 30% SiO2 possessed large latent heat (134.0 J g−1), low supercooling degree (2.01 °C) and excellent form-stable performance without any liquid leakage above melting temperature (8.33 °C). Besides, the composite PCM exhibited an outstanding chemical compatibility, thermal reliability and thermal insulation performance. Considering its desirable properties, TBAB hydrate/SiO2 composite PCM has great potential for cold energy storage.

Temperature dependent solution properties of amino acids in colloidal solutions

Volumetric and acoustic studies of amino acids (l‑aspartic acid and l‑serine) in water and in aqueous cetyl trimethyl ammonium bromide (CTAB) solutions were carried out to understand intermolecular interactions in aqueous solutions of amino acids and in colloidal solutions containing cationic micelles. Density and sound velocity of amino acids solutions of different concentrations in water and in colloidal solutions of CTAB were measured at different temperatures (303.15 K–313.15 K). Volumetric and acoustic parameters like apparent and partial molar volume (Vφ and Vφo), expansibility factor (Eφo), transfer volume, compressibility factors (Kφ and Kφo) and intermolecular free length (Lf) were calculated using measured density and sound velocity data of amino acids solutions. Positive values of Vφ and negative values of Kφ are indicative of strong intermolecular electrostatic interactions among ions of amino acids and water molecules. Presence of CTAB molecules in micellar form in amino acids solutions causes an overall increase in the degree of intermolecular interactions among components of solutions. Moreover, positive values of expansibility factor showed the structure making behavior of amino acids both in water and in aqueous CTAB solutions.

Local flow around a tiny bubble under a pressure-oscillation field in a viscoelastic worm-like micellar solution

The motion of a tiny air bubble in an aqueous solution of cetyl trimethyl ammonium bromide and sodium salicylate (CTAB/NaSal), which forms wormlike micelles, was observed using a high-speed polarization camera. Complex local flow is observed around the bubble surface because the bubble shape deforms repeatedly at 100 Hz. The camera can be used to measure the retardation distribution, which is related to the stress field around the bubble. Different retardation and orientation angle distributions were observed during the contraction and expansion phases. In the contraction phase, a strong retardation distribution appears at the tail of the cusped bubble. The occurrence of uniaxial elongation deformation is considered to be due to the negative wake because they are closely correlated. In contrast, a weak retardation distribution spreads at the upper side of the bubble during the expansion phase, where biaxial extensional deformation occurs due to expansion of the bubble surface. These significant changes in strong elastic stress distributions, which correspond to the orientation angle profiles, can result in increase of bubble rising velocities.

Turn on fluorescent detection for Cd2+ based on surfactant controlled squaraine aggregation

A thymine moiety as ion binding accepter was introduced into asymmetric squaraine fluorophore by amide coupling reaction to develop a new thymine-squaraine based fluorescent chemosensor (SQ). Its detection ability towards heavy metal ions was investigated by UV-vis and fluorescent spectrometry. The results showed that the sensor had high selectivity towards Cd2+ over the other metal ions in aqueous media. Moreover, it was shown that the turn on fluorescence signal occurred in the present of high concentration of cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) solution which resulting in deaggregations of SQ. The stoichiometric ratio was determined by Job's plot analysis as 1:1 and the binding constant as 2.03 × 103 M-1 for the complex between Cd2+ and SQ was further calculated by the Benesi-Hilderbrand plot. The complexation mechanism was proposed according to ESI-MS and NMR results. The following DFT calculation fully supported that the detailed coordination mode of Cd2+ and SQ went through six-membered carbonyl oxygen and the CO group in the amide chain. Finally, the SQ sensor was successfully applied in waste water sample analysis.

Growth, structural and mechanical studies of phthalic acid single crystals grown in two different solutions

Good quality pure Phthalic acid single crystals were grown by slow evaporation solution growth method. Phthalic acid 1(PA1) crystals were grown in Ammonium Oxalate aqueous solution. From the aqueous solution of Ammonium Bromide, Phthalic acid 2 (PA2) crystals were grown. Single crystal x-ray diffraction and Mechanical characterizations of slow evaporation grown single crystals of PA1 and PA2 were analyzed in this article. Lattice parameters, space group and crytal system were found from Single crystal x-ray diffraction analysis. Optical tranmittance study reaveal the optical perfection of the crystals. Mechanical properties such as Vicker’s microhardness number, work hardening index, standard hardness values, Yield strength, fracture toughness, brittleness index and elastic Stiffness constant values were determined using Vicker’s microhardness tester.