Chemical Preparation Research Articles

Antibacterial ability of different activated irrigation after root canal preparation: intratubular analyses.

This study assessed the intratubular antibacterial ability of different activated irrigations after chemical mechanical preparation. Seventy-two palatal root canals of upper molars were infected with Enterococcus faecalis for 4 weeks, and then initial bacterial collection from the main root canal was performed. The root canals were prepared by using a WaveOne Gold large (45/.05) and distributed into 6 groups according to the activation of the final irrigation: ultrasonic activation (UA), XP-Endo Finisher (25/.00), XP Clean (25/.02), EasyClean (25/.04) in reciprocating motion and continuous rotary motion (ECRot), and conventional irrigation. After final irrigation, another bacterial collection from the main root canal was performed, and the root was sectioned transversely in three-thirds and stained for analysis by confocal laser microscopy. Intratubular bacteria were collected through dentin powder and plated for bacterial viability analysis. Intergroup and intragroup comparisons were performed by using analysis of variance and repeated measures analysis of variance, respectively, both at 5% significance. ECRot had higher antibacterial ability than UA (p<0.05), and both were superior to the other groups (p<0.05) in both methodologies. It can be concluded that activation of final irrigation enhances the disinfection of the root canal system, and activators have different efficacies.

Deep eutectic solvents towards green polymeric materials

Solvents are essential for chemical synthesis and material preparation; however, traditional solvents face challenges in meeting safety and sustainability standards.

Recent progress of gas sensors based on perovskites.

Gas sensors convert gas-related information into usable data by monitoring changes in conductivity and chemical reactions resulting from the adsorption of gas molecules. Recently, perovskites have emerged as promising candidate materials for gas sensors, owing to their polar reactivity, chemical responsiveness, and sensitivity. These characteristics enable the detection of the presence and concentration of various gases. This article provides a concise review of recent advancements in perovskite-based gas sensors. First, the chemical composition, structure, and preparation methods of perovskites, as well as the effects of their structure on gas sensing performance, are examined. The key performance parameters of the sensor and the sensing mechanism of the perovskite-based gas sensor are discussed. Then the development of gas sensors based on different structural types of perovskites, including single-component perovskites, mixed-component perovskites, and metal-oxide perovskites, is discussed. Finally, the challenges and opportunities for gas sensors based on perovskites are summarized and prospected.

Hijacking plant skeletons for biomedical applications: from regenerative medicine and drug delivery to biosensing

The review delves into the potential of plant-based scaffolds for tissue regeneration, drug delivery, and biosensing. It highlights chemical principles, preparation strategies, and applications of these scaffolds while addressing challenges and future directions of their usage in healthcare.

Plasmon-enhanced second harmonic generation of metal nanostructures.

As the most common nonlinear optical process, second harmonic generation (SHG) has important application value in the field of nanophotonics. With the rapid development of metal nanomaterial processing and chemical preparation technology, various structures based on metal nanoparticles have been used to achieve the enhancement and modulation of SHG. In the field of nonlinear optics, plasmonic metal nanostructures have become potential candidates for nonlinear optoelectronic devices because of their highly adjustable physical characteristics. In this article, first, the basic optical principles of SHG and the source of surface symmetry breaking in metal nanoparticles are briefly introduced. Next, the related reports on SHG in metal nanostructures are reviewed from three aspects: the enhancement of SHG efficiency by double resonance structures, the SHG effect based on magnetic resonance and the harmonic energy transfer. Then, the applications of SHG in the sensing, imaging and in situ monitoring of metal nanostructures are summarized. Future opportunities for SHG in composite systems composed of metal nanostructures and two-dimensional materials are also proposed.

Activation of biomass precursors and chemical preparation of hierarchical porous carbons for supercapacitor applications

Growing population in the world demands more accumulation of energy. Among the storage devices, capacitors have triggered enormous interest due to its excellent electrochemical characteristics. Activated carbon electrodes from Africana Duranta, Tectona Grandis, and Terminalia Catappa carbon waste, have attracted high interest because of high specific surface area and an abundant pore volume with rational micro/meso pores. The carbon black samples were prepared by a simple green synthesis with KOH treatment followed by pyrolysis method. XRD confirmed the amorphous carbon black allotrope of the carbon black respectively. The carbon obtained from the leaf, Africana Duranta showed high surface area in the range of 9.08 m²/g - 28.592 m²/g with pore radius in the range of 16.768 Å – 877.4509 Å, which was found from BJH and BET analysis respectively. Then the specific capacitance values were calculated from the CV curves using electrochemical analyzer. The highest specific capacitance value of 83.58 Fg-1 was found for Africana Duranta, which was mainly due to high surface area compared to other two leaves.

SYNGAS PRODUCTION BY DRY REFORMING AND BI-REFORMING OF METHANE OVER SOL-GEL MADE Со-Rh/AL2O3 BIMETALLIC CATALYSTS

The most important global challenge of concern for humanity is the change in the Earth's climate due to greenhouse gas (GHG) emissions. In this regard, carbon dioxide reforming of methane is once again attracting more attention as the process uses two major greenhouse gases - methane (CH4) and carbon dioxide (CO2) as feedstock. The reaction product of which is synthesis gas, which is the primary building block to produce various valuable products. Rapid catalyst deactivation due to coking makes industrial development of this process difficult. Additionally, the low H2/CO ratio in synthesis gas, usually below 1.0, limits its further utilization. To solve these issues, it is necessary to create new effective coking-resistant catalysts, improve their chemical and structural composition and preparation methods, and optimize the process conditions. In this work, 5%Co-Rh/Al2O3, a bimetallic catalyst prepared by the sol-gel method (modified Pechini method) was studied in the processes of carbon dioxide and combined steam-carbon dioxide reforming of methane. It was shown that 5%Co-Rh(98:2)/Al2O3 sol-gel catalyst had a high activity in the carbon dioxide reforming of methane. The introduction of steam into the initial CH4-CO2 feedstock allows the regulation of the composition of the produced synthesis gas depending on the amount of water. At t=8000 , the degree of methane conversion is 92.5-95.8%, carbon dioxide – 85.6-97.4%, and H2/CO ratio = 1.0-2.1 depending on the amount of steam added.

Preparation, characterization, and synergistic soil moisture retention effects of a by-product-based dust suppressant for fugitive dust suppression

For the control of dust pollution, a novel dust suppressant was formulated using Resin alcohol C (RC) (by-product of a chemical alcohol preparation from corn) as the main ingredient. Through orthogonal and infiltration experiments, as well as a series of RC screening and optimization processes, an optimal formulation contained 0.3% methylcellulose, 0.1% polyvinyl alcohol, 0.1% cold-water-soluble starch, 0.2% alkyl polyglucosides, and 2.0% RC. The experimental performance results revealed that the by-product dust suppressant had superior water erosion resistance (water loss rate 8.2 %), wind erosion resistance (wind loss rate 7.7% at 20 m/s), durability (suppressed 90.47 % of dust after 50 d), and degradation resistance (mass loss rate of the dust suppressant firm reached ∼43% after 27 d). Fourier-transform infrared spectroscopy and scanning electron microscopy were employed to explore the dust suppression mechanism, which was found to encompass water retention, film-formation, and dust agglomeration. The findings of a pot experiment indicated a synergistic soil moisture retention effect attributed to the implementation of the dust suppressant. This innovative dust suppressant formulation with industrial by-product as the main ingredient offers an effective strategy for mitigating fugitive dust pollution and maintaining soil moisture.

Detection of Heavy Metal Ions Based on Gold Nanoparticles

Gold nanoparticles, abbreviated as AuNPs, have been widely used in catalysis, optics, electronics, and biotechnology due to their unique performance brought by large specific surface area. In recent years, with the improvement of health awareness, the use of gold nanoparticles to detect heavy metal ions has become a research hotspot. The detection is based on colorimetric techniques, which means the metal ions are detected through the color change in solutions. This color change is visible or could be distinguished by ultraviolet-vissible spectrometers. Numerous studies have been published on gold nanoparticles, especially for its synthesis methods. This work introduced the chemical, physical, and biological preparation methods of gold nanoparticles. Understanding mechanisms for detecting heavy metal ions using AuNPs is also very important. Aggregating mechanism, anti-aggregation mechanism, and etching mechanism were also introduced. In addition, applications of using AuNPs to detect heavy metal ions were also introduced. This work will help promote the further development of this technology.

The influence of chemical composition and preparation procedure on CO2 capture performance of NaNO3 /MgO-based sorbents

MgO based sorbents modified by 5–50 mol.% NaNO3 have been prepared by various methods and investigated in detail. It has been showed that optimal synthesis method is incipient wetness impregnation of MgO precursor with sodium nitrate water solution. The highest sorption capacity of 6.5 mmol CO2 g–1 sorb after 1 hour of sorption from the gas mixture with 50 vol.% CO2 at 320 °C was achieved using the MgO modified by 10 mol.% NaNO3. Sorption capacity for MgO modified by 10 mol.% NaNO3 during 10 consecutive sorption-desorption cycles is approximately 4.5–5.5 mmol CO2 g–1 sorb. The duration of the sorption stage is 30 min, the CO2 content in the feed gas is 50 vol.% and sorption-regeneration temperature is 300–350 °C respectively. It has been showed that increasing the sorption pressure to 10 bar allows reducing sorption temperature from 320 °C to 220–260 °C. The sorption capacity is reached up to 4.0 mmol CO2 g–1 sorb at 25 vol.% CO2 that is twice higher than that at 1 bar. It has been demonstrated that steam and hydrogen treatment before sorption doesn’t lead to a significant change in the sorption properties and phase composition of NaNO3 modified MgO-based sorbent.

Effectiveness of the use of biopreparations and fungicides in the cultivation of spring wheat in the forest-steppe of the Priobye

The data on the effectiveness of using chemical, fungal and bacterial fungicides to treat seeds and crops of spring soft wheat in order to limit harmfulness of major diseases are presented. The research was conducted in 2020–2022 on chernozem leached forest-steppe of the Novosibirsk region Priobye. Chemical seed protectant Scarlet and its mixture with Vitaplan were the most effective dressers in the fight against root rots. It has been demonstrated that although biopreparations are inferior in efficiency to chemical ones, they act for a longer period of time and protect the plant from the disease for a longer period of time. Seed dressing with chemical preparation reduced the development of leaf diseases by 53–58%, and with biopreparations – by 34–41%. Titul 390 was the most effective of the vegetation treatments – 60–98%. The efficiency of the biopreparations was 42–64% in the years of moderate disease development. In the years of strong development of septoriosis or powdery mildew, the efficiency of biopreparations did not exceed 22–30%. The biological preparations had a growth-stimulating effect on the plants: they increased the flag leaf area by 22–39%. The seed treatment showed an increasing trend in the number of spikelets, grains per ear and grain weight per ear. Application of the preparations during the vegetation period increased reliably the ear length by 16–28%, the number of spikelets – by 15–20, grains – by 24–31, grain weight per ear – by 33–51%. At seed dressing the greatest increase in the yield (0.15 t/ha) was provided by Scarlet, when using a mixture of biological and chemical preparations it amounted to 0.11 t/ha. When treated during the growing season, chemical fungicide increased the yield by 0.33 t/ha, while biopreparations increased the yield by 0.11–0.14 t/ha. Complex use of chemical preparations (Scarlet + Titul 390) provided the maximum yield increase – 0.62 t/ha, from the joint use of chemical and biological preparation the yield increased by 0.15–0.33 t/ha. The biological preparations increased this indicator by 0.13–0.23 t/ha. It has been concluded that it is possible to select combinations of chemical and biological preparations that can control phytosanitary situation and provide acceptable yield.

Comparison of different preparation methods for oxygen isotope determination of phosphate in mammal tooth enamel

AbstractWe tested several sample pre-treatment protocols for the study of oxygen isotope ratios in the phosphate phase of mammalian enamel of ten different fossil samples. We investigated the effect of different pre-treatment methods and the duration of the hydrogen fluoride treatment on enamel samples from skeletal phosphate with known δ18O values. The samples had been measured previously, so we could compare the ratios measured in our laboratory with the previous values to choose the best chemical preparation procedure. Four pre-soaking methods and two different time intervals of 2 mol dm−3 hydrogen fluoride treatment were compared during our experiments. In our experimental conditions, the distilled water wash and the 6 h of soaking in hydrogen fluoride gave the closest results to the expected δ-values. The steps of the tested preparation processes were repeated at least three times on each sample, so the reproducibility of the process could be also investigated.

Nanosuspensions as carriers of active ingredients: Chemical composition, development methods, and their biological activities

Nanosuspensions (NSps) are colloidal dispersions of particles that have the potential to solve the delivery problems of active ingredients associated with their low solubility in water or instability due to environmental factors. It is essential to consider their chemical composition and preparation methods because they directly influence drug loading, size, morphology, solubility, and stability; these characteristics of nanosuspensions influence the delivery and bioavailability of active ingredients. NSps provides high loading of drugs, protection against degrading agents, rapid dissolution, high particle stability, and high bioavailability of active ingredients across biological membranes. In addition, they provide lower toxicity compared to other nanocarriers, such as liposomes or polymeric nanoparticles, and can modify the pharmacokinetic profiles, thus improving their safety and efficacy. The present review aims to address all aspects related to the composition of NSps, the different methods for their production, and the main factors affecting their stability. Moreover, recent studies are described as carriers of active ingredients and their biological activities.

New triazole-based Schiff base ligands and their Co(II) and Ni(II) complexes as biological potent molecules: Chemical preparation, structural elucidation and biological studies

Preparation of sequence of Co(II) and Ni(II) metal complexes (C1a- C3a and C1b- C3b) of bidentate ligands (L1- L3) has been resulted from the condensation of substituted 1,2,4-triazole with various substituted 1,3-diphenyl-1H-pyrazole-4-carbaldehyde are described in the present study. The structures of synthesized complexes were established by elemental investigation, IR, mass spectroscopy and TGA examinations. The data confirmed that bonding through the nitrogen atom from imine group and sulfur atom of triazole, ligand get integrated with the metal ions in a bidentate nature, gave an octahedral geometry to the complexes. The antibacterial activities have been tested against S. aureus Gram-positive bacteria and E. coli Gram-negative bacteria. Further, through DPPH radical scavenging capacity assay the antioxidant activity values were quantified; all the compounds demonstrate outstanding antioxidant activities. Using molecular docking and highest binding affinities for biological targets, the ligand and complex interactions have been studied. The in vitro anti-proliferative nature of synthesized ligands and their Ni(II) and Co(II) complexes were appraised with the help of SRB assay against Human hepato carcinoma cell (Hep-G2), Lung cells (A-549), Breast cell (MCF-7), Prostate cell (PC-3). Anti-tubercular studies revealed that the complex demonstrates a greater anti-tubercular activity than the analogous ligands.

Study on preparation of ultra-clean coal from bituminous coal using the ionic liquid extraction

ABSTRACT In order to realize clean and efficient utilization of low rank coal, ultra-clean coal preparation is an important method. A clean and efficient method of producing ultra-clean coal is urgently needed, given the high environmental impact and corrosiveness of the chemicals used in the traditional chemical preparation of ultra-clean coal. In this study, ultra-clean coal was prepared by leaching using acidic imidazole ionic liquids, and the effects of temperature, time and concentration on the reaction process were investigated. The ash composition of the sample and the ash removal mechanism under the ionic liquid were revealed, and the evolution law of the microstructure and functional group characteristics was clarified. The research showed that the concentration and temperature had a large influence on the ash content of the product during the leaching process, and the reaction time had a small influence. The minimum ash content of the ultra-clean coal could reach 0.89% (dry basis). In the ionic liquid system, iron, calcium and magnesium in the coal were effectively removed, the iron oxide content was significantly reduced and calcium salts except calcium sulfate were effectively removed, while periclase was almost completely removed. However, the removal of silicon and aluminum was poor. Most of the alumina and silica remained in the ultra-clean coal. Extracted coal had more cracks and rougher surface than raw coal, the BET surface area decreased from 2.8579 to 2.4032. Under the influence of ionic liquid, the Aar/Aal ratio, which evaluates the aromaticity of coal, increased from 0.3702 to 0.8569, indicating that the aromaticity of coal was significantly improved. The CH2/CH3 ratio describing the length and branching degree of aliphatic chains in coal decreased from 4.0849 to 3.1516 which showed that ionic liquids can effectively reduce the length of aliphatic side chains, weakening the coal’s oxidizing activity. The pyrolysis curve of coal shifted to the high temperature zone and the peak temperature increased, indicating the effect of ionic liquids on the chemical stability of coal.

Preparation, Features, and Efficiency of Nanocomposite Fertilisers Based on Glauconite and Ammonium Dihydrogen Phosphate.

This paper studies the chemical and mechanochemical preparation of glauconite with ammonium dihydrogen phosphate (ADP) nanocomposites with a ratio of 9:1 in the vol.% and wt.%, respectively. The methods include X-ray diffraction analysis, scanning electron microscope with energy-dispersive X-ray spectroscopy, transmission electron microscopy, infrared spectroscopy, and differential thermal analysis with a quadruple mass spectrometer. The manufactured nanocomposites keep the flaky glauconite structure. Some glauconite unit structures have been thickened due to minimal nitrogen (ammonium) intercalation into the interlayer space. The globular, granular, or pellet mineral particles of nanocomposites can be preserved via chemical techniques. Globular and micro-aggregate particles in nanocomposites comprise a thin film of adsorbed ADP. The two-step mechanochemical method makes it possible to slightly increase the proportion of adsorbed (up to 3.2%) and intercalated (up to 6.0%) nutrients versus chemical ways. Nanocomposites prepared via chemical methods consist of glauconite (90%), adsorbed (1.8-3.6%), and intercalated (3.0-3.7%) substances of ADP. Through the use of a potassium-containing clay mineral as an inhibitor, nitrogen, phosphorus, and potassium (NPK), nanocomposite fertilisers of controlled action were obtained. Targeted and controlled release of nutrients such as phosphate, ammonium, and potassium are expected due to various forms of nutrients on the surface, in the micropores, and in the interlayer space of glauconite. This is confirmed via the stepwise dynamics of the release of ammonium, nitrate, potassium, and phosphate from their created nanocomposites. These features of nanocomposites contribute to the stimulation of plant growth and development when fertilisers are applied to the soil.

Protective and water-repellent properties of alkylcarboxylic and alkylphosphonic acid films on technically pure magnesium

The formation of superhydrophobic coatings using low‑toxicity corrosion inhibitors is a promising method for corrosion protection of metals and alloys. In this study, the effects of surface roughness and the of the adsorbed substance structure on wettability and corrosion resistance of commercially pure magnesium were investigated. Surface roughness was created by three different methods: paper grinding, etching in nitric acid solution and laser treatment. Oleic, stearic and octadecylphosphonic acids were investigated as potential surface modifiers for the formation of corrosion resistant superhydrophobic coatings. It has been shown that the protective and hydrophobic properties of acid films on magnesium, as well as their stability, are determined by both the initial surface morphology and the nature of the inhibitors. Experimentally, the laser treatment was found to be preferable to mechanical and chemical surface preparation and the best hydrophobic agent among the studied acids is phosphonic acid. The most stable films with excellent superhydrophobic and protective properties in atmospheres of high humidity and salt spray clamber are formed in a solution of 0.001 M octadecylphosphonic acid on the surface of magnesium with high roughness. In addition, the effect of vinyltrimethoxysilane on the protective and hydrophobic properties of stearic acid and octadecylphosphonic acid films was investigated. The results of direct corrosion tests and wetting contact angle degradation kinetics studies showed that the protective and hydrophobic properties of stearic acid can be enhanced by its layer-by-layer adsorption with silane. They practically reach the parameters of octadecylphosphonic acid.

Synthesis and application of biomimetic material inspired by diatomite

Inspired by nature, the design and synthesis of novel biomimetic materials are gradually attracting the attention of scientists. Biomimetic materials with excellent performance are widely applied in medical health, industrial production, agricultural planting, aerospace, etc. As a natural porous biomass material, diatomite has the advantages of high porosity, low bulk density, stable chemical property and large surface area. Benefiting from these advantages, it is of great importance to treat diatomite as bionic substrate to synthesize diatomite biomimetic materials, which can be endowed good structure stability and natural mechanical property. It is an ideal option for crystal growth and uniform dispersion of nanostructures, to improve the agglomeration and high cost of nanomaterials. This review briefly introduces our recent achievements on diatomite biomimetic materials in different application fields. In view of its excellent optical, thermal, chemical and mechanical property, diatomite biomimetic materials have shown extensive application potential in various fields of science and engineering, which include catalysis, corrosion protection, microwave adsorption, super-hydrophobicity, pollutant adsorption, energy storage, etc. It demonstrates that diatomite biomimetic materials with different functional properties can be synthesized by diverse chemical means and preparation methods for different application. By composed of inorganic nanomaterial hybrid, this diatomite biomimetic materials display a three-dimensional network structure with diatomite morphology. The design and synthesis of diatomite biomimetic materials provide more potential bionic categories for different applications, which can accelerate the development of low-cost and high-performance biomimetic materials.

Recent progress in thermal and acoustic properties of natural fiber reinforced polymer composites: Preparation, characterization, and data analysis

AbstractNatural fiber reinforced polymer composites (NFRPCs) have emerged as promising eco‐friendly alternatives over conventional synthetic fiber composites due to their inherent biodegradability, renewability, low environmental impact, and lightweight properties. It has been seen a significant growth in both invention and innovation in the field of NFRPCs. Natural fibers (NFs) reduce the cost of the material by 5%, the weight of the composite by 10%, and the energy required for production by 80%. In terms of thermal, and acoustic properties, NFs can successfully compete with synthetic fibers. As a result, the development of NFRPCs for industrial use has increased significantly in the past decade to meet the growing demands of industrial sectors. To improve the thermal and acoustic properties of NFRPCs, researchers have done a lot of investigation. The aim of the current review is to provide a comprehensive analysis of the existing literature on the thermal and acoustic properties of natural fiber reinforced polymer composites. Thermal properties such as thermal conductivity, TGA, DSC, DMA, and acoustic properties of natural fiber reinforced composites with several parameters, such as different fiber types, different matrix types, fiber weight ratio, fiber to matrix ratio, chemical treatment of fiber have been summarized and analyzed very concisely. This review also emphasizes a summary of different natural fibers, their chemical compositions, composite preparation, characterizations, and future research directions. This article enables the readers, researchers, and manufacturers to realize several opportunities about the latest developments in NFRPCs for the application of thermal and acoustic purposes.Highlights Natural fibers can successfully compete with synthetic fibers, in terms of thermal and acoustic properties. Thermal properties of natural fiber reinforced composites including thermal conductivity, TGA, DSC, and DMA are summarized. Acoustic properties of natural fiber reinforced polymer composites are discussed. Composite materials made of treated fibers result better thermal stability than untreated fiber composites. Sound absorption coefficient generally increases as fiber content increases.

Metal oxide thin film transistor and its active layer materials

Metal oxide thin-film transistors (MOTFTs) have the characteristics of high electron mobility, large-area production, and relatively low fabrication temperature and have received extensive attention as a research hotspot in recent years. Based on a large number of literatures, this paper introduces the typical single-component representative of MOTFT, multi-component compound oxide semiconductor active layer materials such as IZO, IGO, IGZO, etc. At the same time, due to the unique advantages of nanomaterials, material modification is carried out in different dimensions, and six physical and chemical preparation methods of its active layer are described, including a relatively unique Low-temperature preparation method based on improved gel precursor components and UV photocatalysis. Multi-component oxides and composite structures based on nanomaterials are currently the most studied fields, and on this basis, more excellent performance can be studied and prepared. It mainly summarizes its application in large-scale display and flexible electronics and looks at its development direction.