Differential Scanning Calorimetry Thermogravimetric Analysis Research Articles

Tin-antimony/carbon composite porous fibers: electrospinning synthesis and application in sodium-ion batteries

In this work, tin-antimony/carbon composites porous fibers were successfully synthesized by an electrospinning method combined with two-step heat treatment processes, in which SnCl2 and SbCl3 were used as tin and antimony sources, and polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) were used as binders and pore-forming agents. The as-synthesized tin-antimony/carbon composites were systematically characterized by x-ray Diffraction (XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), Energy-Dispersive Spectrometer (EDS), x-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric Analysis-Differential Scanning Calorimetry (TG-DSC). The results indicate that the composite material consists of one-dimensional nitrogen-doped carbon porous fibers as the main matrix, with a three-dimensional network structure in which Sn, SnO2, and SnSb particles are encapsulated. Furthermore, the tin-antimony/carbon composites porous fibers were utilized as self-supported negative electrode for sodium-ion batteries. The results showed that the SNbM-2 sample electrode calcined at 800 °C demonstrated the best cycling stability and rate capability among all the sample electrodes, with a discharge capacity of 319.5 mAh·g−1 maintained after 100 cycles at a current density of 0.1 A·g−1. The excellent electrochemical performance of the SNbM-2 sample electrode is benefited from its unique porous structure and the carbon fiber network structure encapsulating Sn, SnO2, and SnSb particles, which could effectively shorten the Na+ ion transport distance and mitigate electrode volume expansion.

Pozzolanic performance and characteristic analysis of binary blended cement incorporating ceramic polishing sludge

The waste generated during ceramic polishing is typically disposed of in landfills rather than being recycled within the production facility, potentially causing environmental harm. This study aims to enhance industrial waste utilization and reduce CO2 emissions in the cement industry by investigating the feasibility of incorporating ceramic sludge from polishing processes into an innovative binary blended cement. Different binders were prepared with varying amounts of ceramic polishing sludge (CPS), ranging from 10% to 50%, and tested against the ASTM C595 standards. The results were compared with those of ordinary Portland cement (OPC). This approach involves evaluating the pozzolanic activity and conducting an advanced characterization assessment of CPS and binary blended ceramic polishing sludge cement (CPSC) paste. This study employed a combination of physical, mechanical, and chemical tests, including setting time, particle size distribution (PSD), Brunauer-Emmett-Teller (BET) specific surface area, compressive strength, X-ray diffraction (XRD), scanning electron microscopy (SEM), heat of hydration, and differential scanning calorimetry/thermogravimetric analysis (DSC/TGA). The results indicated that CPS can be used as a pozzolanic material to create innovative binders with properties comparable to those of OPC. The Strength Activity Index (SAI) values affirmed the pozzolanic properties of CPS, exceeding 75% for up to 40% CPS replacement. Incorporating CPS in the blended cement resulted in a slower rate of cement hydration, leading to prolonged setting times and reduced early strength development. Although the compressive strength decreased with increasing CPS content, it remained within the acceptable ASTM C595 limits with up to 50% replacement. Nevertheless, the optimal replacement level of OPC with CPS was determined to be 50%. Furthermore, CPS substitution reduced the dry density and improved the water absorption and apparent porosity, reflecting microstructural changes. The SEM images revealed that the blended CPSC had a lower apparent porosity than the pure OPC. The DSC/TGA analysis demonstrated that the blended cement had a lower calcium hydroxide content and higher silica than pure OPC.

Facile synthesis and physical properties of magnesium dititanate nanoparticles for antibacterial applications

AbstractThe modified aqueous co-precipitation approach was used to successfully manufacture magnesium dititanate (MgTi2O5) nanoparticles. Thermogravimetric analysis/differential scanning calorimetry (TG/DSC) was used to clearly reveal the thermal stability. Moreover, pseudobrookite structure, and surface morphology of MgTi2O5 nanoparticles were determined using X-ray diffraction (XRD), transmission electron microscope (TEM), and Fourier-transform infrared (FT-IR), and scanning electron microscope (SEM) techniques, respectively. The average size of the crystallites calculated by Scherer approach was compared to Williamson-Hall and TEM images results. The optical band gap of MgTi2O5 nanoparticles was found to be 3.81 eV for direct transitions. The effect of temperature on the conductivity of DC electricity was tested between the rages 303–503 K. The data on antibacterial activity showed that MgTi2O5 nanoparticles were antimicrobial and stopped the test microorganisms from growing. These findings revealed that MgTi2O5 will be extensively promising in environmental pollution control and antibacterial research.

Impact of preparation methods on the performance of Cu/Ni/Zr catalysts for methanol decomposition

Utilizing waste heat from engine exhausts to decompose methanol into a hydrogen (H2) and carbon monoxide (CO) mixture, subsequently reintroduced into the engine, offers a significant potential to enhance engine efficiency and reduce emissions. The efficacy of the catalyst is crucial, as it directly influences the composition of the decomposition gases, thereby impacting energy conservation and emissions reduction. This study investigates the impact of various preparation methods for the self-developed Cu/Ni/Zr catalyst for methanol hydrogenation decomposition. These techniques include the co-precipitation method, co-impregnation method, and citrate complexation method, evaluated within a temperature spectrum of 220 °C–320 °C. Employing analytical methods such as x-ray Photoelectron Spectroscopy (XPS), x-ray Diffraction (XRD), Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC), Brunauer–Emmett–Teller (BET), Temperature-Programmed Reduction (TPR), and Scanning Electron Microscopy (SEM) analysis, the study elucidates the mechanism of methanol decomposition catalyzed by Cu/Ni/Zr. The findings indicate that the catalyst’s activity, in terms of decomposition rate and hydrogen content, ranks in descending order from the co-impregnation method, followed by the citrate complexation method, to the co-precipitation method.

Biopolymer hydrogel matrices for the stabilization and in-vitro delivery of anti-cancer polyoxometalate [CoW11O39(CpTi)]7−

In the present study, the polyoxometalate (POM), [CoW11O39(CpTi)]7−, known for its significant anti-cancer activity and relatively low toxicity compared to established organic drugs such as CP and 5FU, is investigated. However, it is acknowledged that POMs inherently exhibit toxicity to living cells due to the presence of heavy and toxic metal ions within their core structures and their limited selectivity toward biological targets. Consequently, a methodology to mitigate this toxicity is sought by encapsulating these POMs within hydrogel matrices, with the intention to facilitate slow, sustained release and enhanced target specificity. In this study, the hydrogel of the well-researched anti-cancer POM, K6H[CoW11O39(CpTi)] (hereafter abbreviated as CoW11CpTi), is synthesized through the electrostatic interaction of the positively charged carboxymethyl chitosan (CMC), carboxymethyl cellulose (CMCell), and gelatin, which serve as hydrogelators. Subsequent characterization of the resultant CMC-CoW11CpTi, CMCell-CoW11CpTi, and gelatin-CoW11CpTi gels is performed utilizing Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry/Thermogravimetric Analysis (DSC/TGA), Electron Spin Resonance (ESR) Spectroscopy, Scanning Electron Microscopy (SEM), and Tgel analysis. Among these, the gelatin-CoW11CpTi gel demonstrates the highest stability, retaining its structural integrity for in excess of 10 days. In addition, cytotoxicity assays are conducted on an assortment of cell lines including NRK52e (Rattus norvegicus kidney cell line), MDA-MB-231 (human breast adenocarcinoma), and MCF-7 (human breast epithelial adenocarcinoma). It is observed that the release of POM from the hydrogel matrices under physiological pH conditions exhibits a slow and sustained profile. This study therefore offers a promising approach for the effective delivery of POMs in cancer therapy.

Preparation of [BMIM]HSO4@SiO2 Ionic Liquid Microcapsules and Application to CO2 Adsorption

Carbon emissions are closely related to global climate change and have gradually become a focus of attention. Carbon capture is an effective way to reduce carbon emissions, ionic liquid microcapsules (ILM) have great potential as a CO2 capture material. [BMIM]HSO4@SiO2 ionic liquid microcapsules were prepared by in situ polymerization, and the microcapsule samples were characterized using thermo-gravimetric analysis & differential scanning calorimetry (TG/DSC), scanning electron microscopy (SEM), laser particle size analysis and surface area analyser. The microcapsules on the CO2 adsorption properties were investigated. The results showed that the microcapsule particles have a smooth spherical morphology and uniform size, the average particle size was 146 μm. The TG/DSC showed the microcapsules have better thermal stability. From 273 K isothermal adsorption curve of microcapsules, the sample can reach the maximum adsorption capacity of 4.87 cm3/g STP (standard pressure).

Research on even-odd effects of bio-based Nylon nF salts

Nylon nF is a type of bio-based Nylon, whose raw materials NH2-(CH2)n-NH2 and 2,5-furandicarboxylic acid (FDCA) are both prepared by biological methods. The Nylon nF salts (PAnF salts) are the monomer salts before the polymerization of Nylon nF, whose product quality has a significant impact on the properties of Nylon nF. In this study, Nylon nF salts of FDCA and seven NH2-(CH2)n-NH2 diamines were synthesized. The crystal structures and thermodynamic behaviors of these Nylon salts were determined and analyzed by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), and thermogravimetric analysis-differential scanning calorimetry (TG-DSC). Based on the analysis of melting point and solubility data, it was found that there is a significant even–odd effect between Nylon nF salts (n = 4–10). Moreover, the lattice energy and solvation energy in methanol of these Nylon salts were calculated by Materials Studio (MS) and Gaussian, respectively. The results indicated that there was also an even–odd effect in the lattice energy of Nylon nF salts. It is speculated that these even–odd phenomena were related to the symmetry of the ligand diamines and the stacking mode of Nylon salts. The study of the even–odd effect is significant in predicting and designing the physicochemical properties of cocrystals.

Impact of H2O on CO2 adsorption and co-adsorption: Mechanism and high-performance adsorbents for efficient H2O-CO2 capture

Physical adsorbents used for CO2 capture from air directly and wet CO2 flue gas have limited effectiveness due to competitive adsorption of H2O and CO2. Therefore, it is crucial to understand the impact of H2O on CO2 adsorption and investigate the co-adsorption mechanism in order to enhance the screening, design, and optimization of carbon capture systems. Herein, heat treatments are performed on commercial NaX zeolites to modify the composition of the O-T-O (T = Al, Si) framework. Our systematic investigation based on thermogravimetric analysis/differential scanning calorimetry (TG-DSC), infrared spectroscopy (IR), solid-state nuclear magnetic resonance (SSNMR), and density-functional theory (DFT) calculation, the connection between the structure of NaX zeolite and H2O and CO2 adsorption/desorption is established. The heat-induced changes in the O-T-O (T = Al, Si) framework produce movements of the loaded Na+ ions. Hydrogen bonds formed by agglomerated adsorbed H2O constitute the primary source of desorption heat, which adversely affects CO2 mass transfer and adsorption. Our findings illustrate that modifying the distribution of Na+ ions in the O-T-O (T = Al, Si) framework can reduce the CO2 adsorption energy and prevent the formation of water agglomerates. Our findings provide insights into the design of efficient and high-capacity adsorbents for CO2 capture that can be operated in the presence of H2O.

Synthesis and mechanism study of an environmentally friendly filtrate reducing agent from humic acid and organic silicon

AbstractIn this study, organic silicon was introduced to humic acid for the first time, and set the novel polymer NaHm/AMPS/AM/TSP‐L12 (HASSi) as an environmentally friendly filtrate reducing agent, which was developed by using silica modified material (TSP‐L12), sodium humic acid (NaHm), 2‐acrylamido‐2‐methylpropanesulfonic acid sodium (AMPS), and acrylamide (AM) as raw materials. The molecular structure, chemical composition of HASSi has been investigated and results show that HASSi shows the chemical structure was conformed to the molecular design. Differential scanning calorimetry–thermogravimetric analysis results illustrate that thermal decomposition temperature of HASSi under nitrogen was 250°C. Though temperature resistance evaluations, HASSi could withstand temperature up to 230°C. Salt and calcium resistance evaluations confirmed its resistance of NaCl could reach up to 5% and CaCl2 to 0.5%. The filtrate reduce mechanism of HASSi was investigated through various methods, including scanning electron microscope analysis of HASSi aqueous solution, microstructure of filter cake, measurements of zeta potential, and particle size distribution, results showed that HASSi participation in the formation of mud cakes and illustrated an excellent filtration reduction effect. In addition, HASSi was identified as an environmentally friendly filter loss reducing agent through environmental performance evaluation, which shows a great application prospect in oilfield.

Optical and luminescent characteristics of thermally stable new Eu3+ doped potassium tungstate tellurite glasses for epoxy-free luminescent devices

Transparent, Eu3+ doped potassium tungstate tellurite (TKWZBiEu) glass matrices were successfully synthesized via employing the traditional melt quenching method and their thermal, structural and photoluminescent characteristics were thoroughly investigated. To estimate the aggregate weight loss, glass transition temperature (Tg) and thermal stability factor (ΔT) of the prepared host glass matrix, thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) were utilized. The non-crystalline character of the prepared TKWZBiEu glass was studied via XRD profile. Various vibrational functional groups were revealed via employing Fourier transform infrared (FT-IR) spectroscopy. The optical bandgap (Eopt) values for all prepared TKWZBiEu glasses have been evaluated by employing the absorption spectra. Under n-UV and blue excitations, all the prepared TKWZBiEu glasses are demonstrating reddish emission at 614 nm ascribed to the 5D0 → 7F2 transition, in which the intensity is increasing continuously with Eu3+ ion content up to 5.0 mol%. The experimental lifetime (τ) profiles demonstrate the single-exponential nature of prepared TKWZBiEu glasses under n-UV excitation. Furthermore, temperature dependent photoluminescence (TDPL) spectra indicate excellent thermal stability of the TKWZBiEu glass matrix with the highest value of activation energy (ΔE). The prototype organic epoxy resin/binder-free device has been developed using the 5.0 mol% Eu3+ doped with TKWZBi glass matrix and n-UV LED chip. All the aforementioned findings validate that the optimized TKWZBiEu glass is an auspicious candidate for the red component to fabricate organic epoxy-free w-LEDs.

Thermally Inducing Viscous Fluids to Generate Co-Based Perovskites Enriched with Active Species for the Removal of VOCs.

Various Co-based perovskites are synthesized through thermally driving viscous fluids. In this process, rare earth salts, cobalt salts, and citric acid do not require homogeneous mixing but only need to be heated until they melt into a molten viscous slurry. The physicochemical properties of cobalt-based perovskites were examined using techniques such as X-ray diffraction (XRD), electron paramagnetic resonance (EPR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-Mapping-EDS), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), oxygen temperature-programmed desorption (O2-TPD), and N2 adsorption-desorption. The results indicate that the surface-active species can be controlled by altering the A-site elements of cobalt-based perovskites. All catalysts synthesized through the thermal treatment of viscous mixtures exhibited a low activation temperature and a low apparent activation energy for the catalytic oxidation of toluene. Among all cobalt-based perovskites, LaCoO3 demonstrated the most outstanding catalytic activity, primarily attributed to its capacity to expose a larger number of surface-active sites and oxygen species, as well as its superior reducibility. Furthermore, the formation process of optimal LaCoO3 was monitored using thermogravimetric analysis-differential scanning calorimetry (TGA-DSC), and the byproducts of the low-temperature catalytic oxidation of toluene by the catalyst were identified using gas chromatography-mass spectrometry (GC-MS). The possible mechanism of toluene oxidation was inferred by in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS). Moreover, LaCoO3 exhibits a predominant resistance to high-temperature hydrothermal conditions. This work provides a scalable and innovative approach to fabricating exceptionally effective catalysts for the efficient purification of VOCs.

Performance and Mechanism of Using Low-Cost Fumed Silica Nanoparticles in Enhancing High Viscosity Modified Asphalt

Fumed silica nanoparticles (FSNPs) have shown significant potential in polymer modification due to their economic viability. This study aims to explore the impact of FSNPs on the performance of high viscosity modified asphalt (HVMA). For a comprehensive view, we also introduced Nano-SiO2 and Nano-TiO2, common nano-modifiers, for comparison with the results achieved by FSNPs. The morphology of these nano-modifiers was observed with Field Emission Scanning Electron Microscopy (FESEM). The changes in rheological, chemical, and thermal properties of HVMA before and after modification were evaluated using techniques such as Dynamic Shear Rheometer (DSR), Fluorescence Microscope, Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC). The FESEM results revealed that FSNPs form a branchlike network while Nano-SiO2 and Nano-TiO2 lack specific structures or clear interconnections. Further rheological testing reveals that, when compared to Nano-SiO2 and Nano-TiO2, FSNPs improve the high-temperature performance of HVMA by 2–3 times and bolster its fatigue resistance by 1.2–3 times, while reducing temperature sensitivity. These enhancements are attributed to the synergistic strengthening between the FSNP's branchlike network and the SBS polymer network structure, underlining the significance of FSNPs' shape and connectivity in HVMA rheological property improvement.

Quercetin‐encapsulated magnetoliposomes: Fabrication, optimization, characterization, and antioxidant studies

AbstractQuercetin (QU) faces challenges in its therapeutic efficacy due to its hydrophobic nature and limited oral bioavailability. Using a Box–Behnken design (BBD) approach, we developed QU‐loaded magnetoliposomes (QMLs) to address these limitations. By encapsulating QU within iron oxide nanoparticles (IONPs) and liposomes (LPs), we enhanced its hydrophilicity and improved its potential for drug delivery. Through systematic adjustments of phosal, polyvinyl alcohol, and magnetic/IONPs, we optimized the particle size, zeta potential, and iron content of the QMLs. The formulations underwent comprehensive structural characterization using techniques, such as Fourier transform infrared spectroscopy, X‐Ray diffraction, differential scanning calorimetry–thermogravimetric analysis, and energy‐dispersive X‐ray analysis, whereas their morphology was examined through field emission scanning electron microscopy. Furthermore, we evaluated the in vitro drug release of the QMLs and antioxidant activity of QU, QU‐loaded LPs, and QMLs using DPPH, 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid), and H2O2 scavenging assays, enabling us to compare their antioxidant potential and the efficiency of QU encapsulation within the magneto LPs.Practical Applications: This research holds significant practical implications, particularly in targeted drug delivery using magnetic liposomes. The developed system shows promise in enhancing cancer therapy, providing localized treatment for inflammation‐related conditions, delivering drugs to the brain to address neurological disorders, promoting wound healing, and incorporating quercetin into skincare products for its antioxidant and antiaging benefits.

Crystallographic, spectroscopic and thermal studies of 1-(4-bromophenyl)-5-(2,5-dimethyl-1H-pyrrol-1-yl)-3-methyl-1H-pyrazole.

The new title pyrrole-pyrazole derivative, C16H16BrN3, was synthesized through a citric acid-catalyzed Paal-Knorr reaction between acetonylacetone and 1-(4-bromophenyl)-3-methyl-1H-pyrazol-5-amine under mild reaction conditions. This synthetic protocol is noteworthy for its utilization of stoichiometric amounts of the reactants, an ecofriendly solvent and a cost-effective, non-toxic and biodegradable organocatalyst. A comprehensive understanding of the molecular structure was gained through spectroscopic, thermal and X-ray crystallographic analyses. The crystal structure is characterized by weak interactions, where only C-H...π connections contribute to the hydrogen-bond contacts. The supramolecular assembly is controlled by dispersion forces. However, the energy frameworks demonstrate that these forces act in three dimensions, providing enough stability, as observed in TGA-DSC (thermogravimetric analysis-differential scanning calorimetry) studies.

Preparation of foam concrete from solid wastes: Physical properties and foam stability

The method for preparation of foam concrete from solid wastes were proposed in this study, where soda residue (SR), calcium carbide slag (CS), grand granulated blast-furnace slag (GGBS) and fly ash (FA) were used as raw materials for the binder and Al powder was used as the foam agent. The effects of Al powder, stabilisers and FA content on the dry density as well as compressive strength were assessed to determine the optimal mix proportions. Moreover, to understand the foaming process, the influence of stabilisers on the zeta potential and surface tension of the fresh mixes were measured and Low-Field Nuclear Magnetic Resonance (LF-NMR) was employed to qualitatively characterize the pore size distribution. Finally, the hydration products were analyzed by X-Ray Diffraction (XRD), Fourier transform infrared spectrometer (FTIR), Thermogravimetric Analysis-Differential scanning calorimetry (TGA-DSC), Scanning electron microscope-Energy dispersive X-ray spectroscopy (SEM-EDS). The results suggested that the optimal content of Al powder was 1–2%, and the combination of S and P (SP) stabilisers showed better stabilization effect than the single use of S or P, leading to well distributed foam with smaller size. The stabilization effect was attributed to the dissolved negative complex that absorbed on the foam film to increase the repulsion between foams as well as to reduce the surface tension of the fresh mixture. The substitution of GGBS by FA generally resulted in reduced dry density and compressive strength, while the extent varied with the addition of stabilizers, and thus the optimal amount of FA depended on the selection of stabilisers. Overall, our study highlighted the potential of using industrial waste materials for producing sustainable light weight concrete with satisfactory dry density and compressive strength.

Evaluation of the physical properties and filtration efficiency of PVDF/PAN nanofiber membranes by using dry milk protein

In engineering applications, especially ultrafiltration (UF) applications, it is very important to use polyacrylonitrile (PAN) and poly (vinylidene fluoride) (PVDF) nanofiber membranes. In this study, membrane nanofibers made of pure PAN, PVDF: PAN blends, and pure PVDF (M1, M2, M3, M4, M5, and M6), were produced by the electrospinning technique with different contents of PVDF in each blend. The prepared membranes were characterized by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), contact angle measurements, x-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrophotometry, and differential scanning calorimetry-thermogravimetric analysis (DSC-TGA). In terms of the physical properties, the viscosity of the membranes increased with an increase in the content of PVDF in the blends compared with the viscosity of the pure polymer solutions. This led to increases in nanofiber diameter, pore size, and porosity by 261.664%, 875.107%, and 114.41%, respectively, when the content of PVDF increased from 20% (M2) to 80% (M5); this was also accompanied by an increase in the surface wettability of the membrane depending on its contact angle. In addition, the thermal properties and crystallinity of PAN improved after increasing the PVDF content from 20% (M2) to 60% (M4). Moreover, the filtration efficiency of the membranes was measured to determine the per cent reduction in pure water flux, reduction in mean depth (RMD) before and after using dry milk protein, the flux recovery ratio and porosity, giving values of 15.68%, 82.51%, 84.32%, and 67.79%, respectively, for the M4 membrane.

Thermokinetic and Ballistic Property Studies of Azide‐Based Airbag Gas Generants with Dual Oxidizers (Sr(NO3)2 and KNO3)

Thermokinetic degradation studies of an airbag gas generant ternary mixture comprising NaN3, KNO3, and SrNO3 are carried out for the first time using simultaneous differential scanning calorimetry–thermogravimetric analysis. The results point toward the fact that the use of dual oxidizers has improved the reactivity of the azide‐based airbag gas generant mixture and reduced the amount of residual masses remaining after degradation to a minimal value of 2%. The activation energy of the mixture is also found to be increased to a maximum value of 249 kJ mol−1 which is better than the conventional airbag mixtures. The ballistic property studies done on the ternary mixture show that it can activate the airbag within 43.3 ms of crash which is very much an improved timeframe compared to the existing airbag mixtures. The study indicates that stoichiometric mixture containing NaN3/Sr(NO3)2/KNO3:75/12/13 by weight can be used as a potential airbag gas generant for automotive airbags. The blended mode methodology used in this research work combining the thermokinetic and ballistic property measurement can be effectively used to evaluate the performance parameters of airbag gas generants.

Structural analysis and properties of three novel sulfonic acid-based pharmaceutical salts of paliperidone

Three novel paliperidone sulfonate salts, including salt 1 (paliperidone methanesulfate), salt 2 (paliperidone benzenesulfate), and salt 3 (paliperidone p-toluenesulfate), were successfully designed and synthesized using a slow solvent evaporation method. Through TGA-DSC (thermogravimetric analysis-differential scanning calorimetry) testing, it was observed that the decomposition temperatures of these newly developed pharmaceutical salts were increased by 90 K, highlighting their enhanced thermal stability compared with paliperidone. The formation of these salts was primarily attributed to intermolecular hydrogen bonding interactions, as revealed by single-crystal structure analyses. Furthermore, the analyses of 3D dnorm Hirshfeld surface and 2D fingerprint plots demonstrated that the molecular stability was further enhanced by the interactions of H···H and H···O. Salt 1 showed a 10-fold increase in solubility and an approximately 200-fold increase in dissolution rate in a variety of simulated human body fluid environments. The confirmation of the formation of paliperidone drug salts and the high purity of the synthesized salts were further supported by PXRD (powder X-ray diffraction) and IR (infrared spectroscopy) analysis. Notably, this study represents the first reported investigation of paliperidone sulfonate salts, potentially providing valuable insights for the improvement of paliperidone pharmaceutical formulations.

Study of Low-Pressure Combustion and Luminescence Properties of Different Magnesium/Nitrate Pyrotechnics

ABSTRACT To explore the effect of pressure on the combustion and luminescence properties of magnesium/nitrate pyrotechnics, four sets of zero-oxygen-equilibrium magnesium/sodium nitrate (N), magnesium/potassium nitrate (K), magnesium/barium nitrate (B), and magnesium/strontium nitrate (S) pyrotechnic samples were subjected to TG-DSC (thermogravimetric analysis-differential scanning calorimetry) testing and combustion tests at atmospheric pressure and 1 kPa. The combustion experiments showed that the flame height increased at 1 kPa due to the rapid diffusion of gas products. Moreover, the degree and rate of oxidation of magnesium are limited by the scarcity of oxygen in the environment, resulting in a decrease in both combustion temperature and luminous intensity at low pressure. Thermal analysis tests showed that B and S have higher combustion temperatures and better luminescence performance at 1 kPa because of their higher low-pressure reactions than N and K. In addition, the Mg/Sr(NO3)2 red light tracer has the best luminescence performance at low pressure because it still has a higher concentration of visible light emitter SrOH at 1 kPa. These scientific findings provide useful insights into the low-pressure combustion behavior of pyrotechnics and support the growing demand for military and civilian applications.

Production and characterization of a novel poly amino acid from a thermophilic bacterium, and preliminary testing of its coagulating potential for imminent wastewater treatment application

The increasing demand for biopolymers across diverse fields, such as food, medicine, cosmetics, and environmental applications, has prompted researchers to explore novel molecules with enhanced functionalities that meet these demands. In this study, a thermophilic strain of Bacillus licheniformis was employed to produce a unique polyamino acid. This thermophilic isolate exhibited rapid growth at 50 °C in a sucrose mineral salts medium, resulting in a biopolymer concentration of 7.4 g/L. Interestingly, the biopolymer produced at different temperatures exhibited varying glass-transition temperatures (ranging from 87.86 °C to 104.11 °C) and viscosities (7.5 cP to 16.3 cP), suggesting that the fermentation temperature significantly influenced the degree of polymerization. Furthermore, the biopolymer was characterized using various techniques, including Thin Layer Chromatography (TLC), Fourier Transform Infrared (FTIR) spectroscopy, Liquid Chromatography-Electrospray Ionization-Mass Spectroscopy (LC-ESI MS), Nuclear Magnetic Resonance (NMR), and Differential Scanning Calorimetry-Thermogravimetric Analysis (DSC-TGA). The results revealed that the obtained biopolymer was a poly amino acid, with poly-γ-glutamic acid as the major monomeric component in the polymer backbone with a few appendages of aspartic acid residues in its side chain. Finally, the biopolymer demonstrated significant coagulation potential for water treatment applications, as evidenced by coagulation studies conducted under varying pH conditions using kaolin-clay as a model precipitant.