TG-DTG Analysis Research Articles

A novel all-solid-waste binder prepared by salt-alkali synergistic activation system constructed from phosphogypsum, soda residue and calcium carbide slag

Conventional alkali-activated slag materials apply strong industrial alkalis with high cost and potential corrosion risk. Alternatively, this study utilized industrial solid waste phosphogypsum, soda residue, and calcium carbide slag to construct a salt-alkali synergistic activated system. A new salt-alkali synergistic activation effect was formed by the SO42- introduced by PG together with the Cl- and OH- provided by SR and CS, which promoted the hydration reaction. AFt, Friedel's salt, C-(A)-S-H, and other hydration products were generated and congregated, and a new all-solid-waste binder was created with 3d/28d strengths of 17.9/43.9 MPa, meeting the P·O 42.5 cement strength standard requirements. By conducting compressive strength and drying shrinkage tests on mortar and paste specimens with varying ratios, and employing XRD, TG-DTG, FTIR, and SEM-EDS analyses, the mechanical attributes of the binder were systematically assessed, and its hydration process was elucidated.

Green Synthesis of Luminescent Carbon Dots from Ficus benghalensis Aerial Roots for Bioimaging.

In this work, carbon quantum dots (CQDs) were prepared using a one-step hydrothermal green synthesis method from a low-cost and eco-friendly renewable biomass, specifically the Ficus benghalensis aerial roots (FB-AR). For the past two decades, CQDs have been noted for their tunable emission spectrum, quantum yield, biocompatibility, photostability, and unique optoelectronic properties such as photoluminescence (PL), and fluorescence. The synthesized Ficus benghalensis carbon quantum dots (FB-CQDs) were characterized for their physical, structural, and chemical properties using XRD, Raman, HRTEM, XPS, FTIR, TG-DTG, UV-visible, and photoluminance analysis. XPS analysis confirmed the presence of phytoconstituent functionalities and the composition of components. The FB-CQDs, which exhibit long-range emissions, have potential applications in various biological and therapeutic fields. Their bioimaging capability is tested in Escherichia coli bacteria. However, despite their promising characteristics, the FB-CQDs showed no antibacterial inhibition against Escherichia coli and Staphylococcus aureus, likely due to its carbonization temperature.

Effect of rich-MgO from low-calcium limestone on the calcination and properties of C4A3$-C2S clinker

As one type of low-calcium cement, C4A3$-C2S clinker consumes less energy and can utilize rich-MgO low-calcium limestone. The effect of rich-MgO low-calcium limestone on its calcination and properties is studied by means of f-CaO, XRD Rietveld refinement, TG-DTG and Lithofacies analysis. The results show that 3%∼5% MgO can promote the absorption of f-CaO and accelerate the formation of highly active monoclinic C3S and C4AF in clinker. When the MgO content is 7% and 8%, C4A3$-C2S clinker calcined at 1380°C has excellent mechanical properties and its soundness is still qualified. This research shows that the rich-MgO low-calcium limestone can replace more than 50% of natural limestone to prepare C4A3$-C2S clinker in cement industrial production.

The influence of addition of fly ash from biomass combustion on selected properties of red building ceramics

The paper characterizes waste in the form of fly ash generated in a power plant during the combustion of biomass in a fluidized bed in terms of its possible use in the ceramic building materials industry. This is important from the point of view of environmental protection. In order to assess the possibility of using ash in the production of red ceramics (e.g. bricks), two different clay raw materials (Clay I and Clay II) were selected to prepare the raw material sets. First of all, the investigated fly ash was subjected to thermogravimetric TG-DTG analysis and its basic chemical composition was determined. Then the specific density was determined for all the raw materials, XRD analysis was also performed and finally characteristic temperatures were determined by means of a high-temperature microscope. The basic raw material sets included clayey raw material and fly ash in various contents: 5 wt%, 10 wt% and 15 wt%. Samples were pressed from the ready sets and fired at the temperature of 1000℃. Afterwards, the obtained samples were subjected to XRD and microstructural tests, then selected physical properties were determined, i.e. water absorption, porosity, apparent density, and compressive strength. Based on the research and analysis of the results, it was found that the introduction of fly ash from biomass combustion into the raw material set in the range of 5–15 wt% has a positive effect on the insulating properties of red ceramics. In addition, the density of the red ceramics decreases with the increase in the addition of fly ash, while its porosity and water absorption increase. Furthermore, the addition of fly ash decreases the compressive strength and visually brightens the microstructure of the products.

Investigating key factors for superior CRMC-based mortars cured under CO2 pressurized environment

An exploratory programme was undertaken to individually test the influence of reactive magnesia to waste-based material (biomass fly ash) ratio, water to solids in binder ratio, static compaction pressure, accelerated carbonation curing period, and curing temperature, on the compressive strength results of Carbonated Reactive Magnesia Cement (CRMC)-based mortars. Subsequently, the observed optimal conditions of each parameter were combined to assess their influence when applied together. A total of twenty-four mixture labels were designed, with specimens moulded under static compaction pressure and subjected to a pressurized accelerated carbonation curing under controlled conditions. The devised mortars were evaluated through compressive strength tests, and the microstructure was carried out through TG-DTG, ATR-FTIR, XRD, SEM-EDX, and MIP analyses. The results demonstrated that none of the tested influencing factors can be exclusively considered as the sole determinant for the compressive strength outcomes. Thus, this study highlights the importance of thoroughly considering any modifications in both mixture design and accelerated carbonation curing conditions to achieve the optimal properties of CRMC-based mortars. Additionally, the devised CRMC-based mortars exhibited favourable binding properties with biomass fly ashes, allowing for its secondary use and contributing to waste circularity by avoiding landfill disposal, supporting the development of the waste circularity and CO2 sequestration through mineralization in carbonated materials.

SnO2-TiO2 materials for photocatalytic degradation of cationic dye under UV and visible light and a chitosan composite film investigation

The possibility of SnO2 incorporation and immobilization as films forming composites opens new perspectives for TiO2 to profit visible light and to facilitate the photocatalytic process, respectively. In this study, 0 %, 1 % and 10 % wt. of SnO2 was incorporated into TiO2 (SnO2-TiO2) by coprecipitation in a sol-gel method by ammonia addition, followed for calcination at 500 °C. The photocatalysts were characterized by N2 adsorption-desorption, FTIR spectroscopy, XRD Rietveld refinement, TG-DTG, SEM-EDS, DRS and elemental analysis. The performance of all solids was evaluated in the photocatalytic degradation of the cationic dye methylene blue in aqueous phase, under visible and UV irradiation, at 25 °C for 2 h. The results showed that the incorporation of Sn into TiO2 improved the textural properties and decreased the bandgap. All solids presented only TiO2 typical diffractograms, with anatase as the main phase, but catalyst with 10 % SnO2 presented also brookite phase, inferring that Sn atoms were incorporated into TiO2 structure, corroborated by MEV results. All tin-based photocatalysts show high activity under UV and visible light, with the 10 % SnO2 material reaching 83 % and 88 % degradation after 2 h under UV and visible radiation, respectively. This material was tested as an immobilized film, achieving 14 % of decolorization, and the reuse was also evaluated. Our investigation demonstrates that SnO2-TiO2 catalysts could be used to decompose a dye under UV and Visible light as powder in a batch reactor and immobilized as a composite film with chitosan, that opens new perspectives to facilitate the application using solar light.

Electrochemical polymer synthesis using thiophene and pyrrole/carbazole: Their electrochemical behaviours and capacitor performance

In this study, carbazole-derived monomers were synthesized on ITO-coated PET via electrochemical reactions and conductivity measurements of the resulting polymeric films were performed by UV, FT-IR, NMR, TG-DTG, SEM and AFM analyses. Their spectroelectrochemical properties were investigated. The carbazole (C) based thiophene (Th) polymer abbreviated as pThC and its copolymer with pyrrole (Py), named as pThC-Py were obtained by electrochemical polymerization method. The surface stability of the resulting polymer films was good depending on time. The contact angle (CA) between the water and theco- polymer surface was determined by dropping 6.09 μL of pure water and CA average was calculated as 68.19° < 90°. According to the thermal analysis data of the polymers, the thermal stability of the pThC-Py was better than pThC as it had higher thermal decomposition temperature. Comparisons of electrical conductivity measurements of the polymer films were made depending on the temperature (25, 50 and 90 °C). Due to increasing temperature, the electrical conductivity of pThC-Py film was read as 29.3 S/cm at 90 °C, and also the electrical conductivity values of the pThC-Py were determined as 1.92 × 10−2 S/cm at 25 °C and 14.2 S/cm at 50 °C. Because of the high electrical conductivity of the pThC-Py, its capacitor performance was tried to be determined from cyclic voltammetric measurements. According to the voltammetric results, the power density (P) and the energy density (E) values of the synthesized substance were calculated as 290.532 W/g and 9.684 Wh/g, respectively. This indicates that the amount of energy the material storable is relatively high. Moreover, it is possible to say that it can be included in the classical capacitor class and in the supercapacitor category by improving its features. Moreover, since the electrical conductivity of pThC-Py is quite good, it is thought that it may be suitable for use in electronic devices.

Influence of anionic species on the low temperature pyrolysis performance of heated tobacco sheets catalyzed by sodium salts.

Development of low temperature catalytic pyrolysis technology for heated tobacco sheets is expected to increase the aroma of heated tobacco products and improve their overall smoking quality. In this study, the low temperature pyrolysis performances of heated tobacco sheets catalyzed by various anionic sodium salts were investigated using TG-DTG, Py-GC-MS technology and smoke routine chemical composition analysis. The results showed that the total weight loss between 100°C and 300°C increased by 7.8%-13.15% after adding various anionic sodium salts, among which, sodium acetate and sodium tartrate showed a relatively higher weight loss. The relative content of free hydroxyacetone, furfuryl alcohol, butyrolactone and megastigmatrienone in the pyrolysis gas increased, while the relative content of free nicotine decreased. With the change of anionic species, the catalytic decomposition ability of cellulose, lignin, and other substances may change, resulting in the distribution alteration of compounds in the pyrolysis gas. After adding sodium acetate and sodium citrate, the release of total particulate matter (TPM), glycerol, and nicotine in flue gas increased. Overall, the addition of sodium acetate and sodium citrate showed a higher low temperature pyrolysis performance of heated tobacco sheets. The research results in this paper provide data support for changing the low temperature catalytic pyrolysis performance of heated tobacco sheets by adjusting the type of anions in sodium salts.

Physical, mechanical properties and microstructure of waste GBFS-based geopolymer incorporated with metakaolin and SiC whiskers(SiCw)

Geopolymer, known as alternative materials to ordinary Portland cement, possess superior properties. This study employed varying dosages of metakaolin from 0 to 30 % and silicon carbide whiskers (SiCw) from 0 to 0.05 % to enhance GBFS-based geopolymer matrix. The process began with the dispersion of SiCw in an alkaline activator through magnetic and ultrasonic stirring, followed by the preparation of the geopolymer. Physical and mechanical characteristics were evaluated to reveal the improvement effects of metakaolin and silicon carbide whiskers on the geopolymer. Techniques such as FTIR, XRD, and SEM-EDS were utilized to analyze the morphology, chemical components, and mineral phases. Pore size distribution and microstructural rearrangement were assessed using MIP and 29Si NMR. Additionally, TG-DTG analysis was conducted to analyze thermal stability. The results indicated that optimal additions of metakaolin and SiCw increased interactions among gel products and induced more chemical reactions, thus exhibiting better mechanical strength and thermal properties. The water absorption and permeable porosity were also improved. The inclusion of SiCw notably provided more nucleation sites and increased the dissolved aluminum content, enriching the phase in the system.

Enhanced surfactant remediation of diesel-contaminated soil using O3 nanobubbles

Currently, nanobubbles are widely discussed in environmental research due to their unique properties, including significant specific surface area, transfer efficiency, and free radical generation. In this study, O2 and O3 nanobubbles (diameters ranging from 0 to 500 nm) were combined with conventional surfactant technology to investigate their enhanced efficacy in removing diesel contaminants from soil. The impact of various factors such as surfactant concentration, temperature, and soil aging duration on pollutant removal rates was examined across different experimental approaches (stirring/flushing). Soil samples subjected to different treatments were characterized using TG-DTG and FTIR analysis, while GC/MS was employed to assess the degradation products of diesel constituents in the soil. The results indicated that the elution efficiencies of the three surfactants (SDS, SDBS, and TX-100) for diesel in soil correlated positively with concentration (0.3–1.4 CMC) and temperature (18–60 °C), and inversely with aging time (10–300 days), with the elution capacity was SDS > SDBS > TX-100. Mechanical stirring (500 rpm) and temperature variations (18–60 °C) did not affect the stability of the nanobubbles. Upon the introduction of O3 nanobubbles to the surfactant solution, there was a consistent increase in both the removal (degraded and removed) efficiency and rate of diesel under varying experimental conditions, resulting in an enhancement of removal rates by approximately 8–15%. FTIR spectroscopy showed that surfactants containing O3 nanobubbles mitigated the impact on the primary functional groups of soil organic matter. GC/MS analyses indicated that residual pollutants were predominantly alkanes, with degradation difficulty ranking as: alkanes < alkenes < cycloalkanes < aromatic compounds. TG-DTG coupled with GC/MS analysis demonstrated that O3 nanobubbles contributed to a reduction in surfactant residues. This study significantly advances our understanding of how nanobubbles facilitate and optimize surfactant-assisted remediation of contaminated soil, thereby advancing the precise application of nanobubble technology in soil remediation.

Utilizing the Adsorbability of Pseudoboehmite for Tailoring the Stability of an Aluminum Sulfate Alkali-free Accelerator for Shotcrete.

Shotcrete is widely used in tunnels, bridges, culverts, and other large-scale projects. The accelerator is an additive employed to expedite the setting time of shotcrete. Previous research primarily concentrated on enhancing the early strength of accelerators, whereas their long-term stability has been inadequately investigated. In this study, pseudoboehmite (PB) and amorphous aluminum hydroxide (AAH) were incorporated into the accelerator to enhance its stability over a period of 90 days without any signs of crystallization or delamination. Furthermore, the accelerator exhibited an initial setting time of 170 s, a final setting time of 550 s, and a compressive strength of 11.58 MPa after 1 day. The mechanism of effects was studied by isothermal calorimetry, FTIR, XRD, TG-DTG, and SEM analysis. The enhancement in stability is attributed to the distinctive adsorption and thixotropic properties of PB, which facilitate the formation of an electrical double-layer structure in acidic solutions. The expedited setting and hardening are primarily due to the equilibrium between Al3+, SO42-, and Ca2+ ions, which accelerates the hydration process of cement. This research offers a methodology for developing a high-performance, alkali-free liquid accelerator.

Production of eco friendly DME fuel over sonochemically synthesized UiO66 catalyst

The ultrasound-assisted preparation of UiO-66 was carried out at T = 80–220 °C, and the catalytic performances were evaluated in methanol conversion. Also, physicochemical properties were assessed by XRD, SEM, PSD, FTIR, N2 adsorption–desorption, TG-DTG, and NH3-TPD analysis. The characterization proved that increasing the synthesis temperature positively affected the crystallinity, specific surface area, thermal stability, and acidity of the catalysts. Besides, the catalysts' performance was investigated in the methanol conversion reaction (T = 350–450 °C, P = 1 atm, and WHSV = 5 h−1), leading to the DME (Dimethyl Ether) production. Rising reaction temperature increased the methanol conversion and DME yield. The synthesized sample at 220 °C had the best properties and performance with conversion and yield of about 38% and 51%, respectively. The stability test for the UiO-66-220 (University of Oslo 66) catalyst was performed at 450 °C for 12 h, and the activity remained stable for about 5 h. Furthermore, the used catalyst was characterized via XRD and TG analysis.

Early mechanical strength, hydration mechanism and leaching behavior of alkali-activated slag/fly ash paste filling materials

The enhancement of the early strength of the filling body is regarded as a critical technology for shortening the mining & filling cycle and achieving efficient production. It is a high-value utilization pathway to entirely replace Ordinary Portland Cement (OPC) with industrial waste residue. Hence, in this research, ground granulated blast furnace slag (GGBFS) and fly ash (FA) were selected as aluminosilicate precursors. The effects of single-component and binary activation of Na2SiO3, Na2SO4, Na2CO3, NaOH, NaAlO2 and triethanolamine (TEA) on the mechanical strength of backfill were systematically investigated. The microstructural evolution mechanism of hydration products was elucidated using XRD, TG-DTG, SEM and MIP analyses. The leaching characteristics and immobilization mechanism of heavy metals were further revealed. The experimental results indicated that the activator contributed an alkaline environment and active ions to the initial hydrolysis reaction of precursors and the polycondensation reaction of silica tetrahedra and aluminum tetrahedra with Ca2+ drove the hardening and development of the hydration products. Na2SiO3 exhibited the superior activation effect among single-component activators, while the binary activator presented notable “promoting and inhibiting characteristics”. Moreover, the binary activator composed of 4% Na2SiO3 and 4% NaAlO2 conducted the highest compressive strength at 3 d and 7 d. The dominant hydration products of the backfill were ettringite, C-S-H gels, C-A-S-H gels and zeolite-like products. The density of microstructures and the crystallinity of hydration products were significantly enhanced ascribed to the synergistic and complementary effects of Na2SiO3 and NaAlO2. Heavy metals were immobilized by the hydration products through physical encapsulation and chemical bonding, and the leaching concentrations of all heavy metals (Pb, Cd, Cr(Ⅵ), Zn, Mn, As and Cu, etc.) were lower than the standard limits of Class III in GB/T 14848-2017.

Synthesis of some new nanoparticles mixed metal complexes of febuxostat in presence of 2,2′-bipyridine: Characterization, DFT, antioxidant and molecular docking activities

New Mn(II), Fe(III), Co(II), and Ni(II) complexes with urate lowing drug febuxostat (FEB) and 2,2′-bipyridine (Bipy) were designed and depicted. Elemental analysis, molar conductance, magnetic measurements, FT-IR, UV–visible, 1H NMR, mass spectrometry (MS), X-ray diffraction (XRD) and thermal analyses (TG-DTG) studies were used to depict complexes. The FT-IR data revealed that the FEB and Bipy have two donating sites, the oxygen of the carboxylate group and the sulfur atom of the thiazole ring in FEB while, Bipy has two nitrogens of the pyridyl ring. Based on information from the magnetic and electronic spectra, an octahedral geometry was suggested for complexes. The nature of the water molecules and their thermal stability were investigated using TG-DTG analyses. By Coats-Redfern equations determined thermodynamic properties in addition to Horowitz-Metzger equations. The purpose XRD examination of compounds was used to determine the compounds (crystalline or amorphous), average crystallite size (Cs) and Crystallographic data. The bond angles, bond lengths, dipole moment, total energy and equilibrium geometry of metal complexes were investigated by DFT calculations. FEB exhibited an antioxidant action in addition to its metal complexes, with IC50 values of 0.124, 0.316, 0.635, 0.186 and 2.234 mg/mL for FEB, Mn(II), Fe(III), Co(II) and Ni(II) compounds, respectively. The molecular docking data demonstrated that the complexes have competent stabilizing scores of −6.66, −6.50, −7.18 and −7.59 kcal/mol, respectively. The data of Co(II) complex revealed the most promising potential xanthine oxidase inhibitory activity.

Statistical optimization, characterization and effect of process variables on cotton stalk pellets using tractor drive pelleting machine.

In present study, the development, production, characterization and economic analysis of pellets made from cotton stalk in a tractor PTO-based pelleting machine are investigated. The cotton stalk is widely available in the southern part of India and has a huge potential in bioenergy generation due to its salient physicochemical composition. Many regions of Southern India are suffering from an electricity shortage, and therefore to overcome on this issue, an energy-efficient, portable, tractor PTO-operated pelleting machine was developed that can be operated directly on the field to reduce the transportation cost of agro-residues. The Box-Behnken design using response surface methodology (RSM) was employed to evaluate the performance of the pelleting machine. Based on the ANOVA results, the pelleting efficiency, pelleting capacity, bulk density of pellet and fuel consumption were obtained to be 87.06%, 42.65kg/h, 614.09kg/m3 and 1.12 lit/h, respectively. In order to examine the physicochemical properties of cotton stalk pellets, the proximate, ultimate, physical, TG-DTG, FTIR and SEM analysis have been carried out. As a result, the ash content, calorific value, shattered index and durability of cotton stalk pellets were found to be around 2.73%, 18.92MJ/kg, 92.80% and 93.75%, respectively. A combustion characteristic of pellets using TGA analysis exhibited a maximum mass loss (43.5%) observed in between 180 and 350°C due to the degradation of cellulose and hemicellulose, whereas a SEM analysis of cotton pellets justified its homogeneous morphology along with rich concentration of minerals. The benefit-cost ratio and payback period of developed tractor PTO-operated pelleting machine for cotton stalk were found to be 1.11 and 33.1months, respectively. The internal return of rate was observed to be 74%.

Lysozyme–Mineral Clay Systems: Comparison of Interaction for Controlled Release in Feed Application

A synthetic approach to bond lysozyme (LY) to commercial natural carriers, namely clay minerals (bentonite, BN; and sepiolite, SP) and commercial zeolite (Phil 75®, PH), already in use in feed formulation, is proposed. The synthetic route, which implies solid–liquid adsorption, is a simple and effective way for preparing hybrid materials characterized by LY loadings up to 37 mgLY/gcarrier. By operating at pH 4.3, initial LY content of 37.5 mgLY/gcarrier, and reaction time of 90 min, hybrid materials with LY loadings of 37, 35, and 12 mgLY/gcarrier for LY-SP, LY-BN, and LY-PH, respectively were obtained. The LY initial concentration and pH, as well as the physico-chemical properties of the carries were found to be the parameters that govern the synthesis of the materials. The driving force for an effective LY adsorption and interaction is the combined Zero Point Charge (ZPC) of the carriers, always negative (in the range between −4 and −170 mV) and the positive ZPC of LY, as well as the carrier morphology, characterized by mesoporosity (pore dimensions in the range of 5–12 nm). However, it is the interaction of charges of opposite sign that mainly affects LY loadings and bond strength. Based on SEM-EDX analysis, LY molecules are quite homogeneously spread onto the carriers’ surface. TG-DTG analyses showed that the LY–carrier interaction in the hybrid materials is stronger than that in a simple mechanical mixture of the components. Specifically, in the hybrid materials, the phenomenon at 300 °C, associated to LY decomposition, is broadened and slightly shifted towards higher temperatures (320–350 °C), whereas in a mechanical mixture of the same composition, it occurs at temperatures closer to those of free LY, as if there were no or very weak interactions. At pH 3, a very little LY release, 0.03 and 0.01 mgLY/gcarrier, was found for LY-BN and LY-PH, respectively. The latter became larger at pH 7, 0.06 mgLY/gcarrier for both BN and PH carriers, suggesting that BN and PH are better modulators of LY release. The paper provides insights for the study and the development of new optimized feed formulations for the targeted delivery of natural compounds with antimicrobial activity, alternatives to antibiotics, and vaccinal antigens.

Green Synthesis of Nanomagnetic Copper and Cobalt Ferrites Using Corchorus Olitorius

This study aims to develop a self-combustion method for use in the preparation of copper and cobalt ferrites. This development was based on the full use of dry leaves of Corchorus olitorius plant in order to stimulate the preparation of the studied ferrites by making full use of the small amount of carbon produced from the combustion process. The fabrication of CuFe2O4 and CoFe2O4 with spinel-type structures and the Fd3m space group is confirmed by XRD and FTIR investigations. Two major vibration bands occur laterally at 400 cm−1 and 600 cm−1. We were able to understand the existence of two stages through the thermal behavior based on TG-DTG analysis for the materials under investigation. The first is from room temperature to 600 °C, which indicates the formation of reacting oxides with Co or Cu ferrites, while the second is from 600–1000 °C, which indicates the growth in the ferrite fabrication. The surface morphological analyses (SEM/EDS and TEM) display formation of homogeneous and nanosized particles. The surface properties of the samples containing CoFe2O4 are superior compared to those of the samples not containing CuFe2O4. Every sample under investigation displays type-IV-based isotherms with a type-H3 hysteresis loop. The VSM approach was used to evaluate the magnetic characteristics of Cu and Co ferrites. Copper ferrites have a magnetization of 15.77 emu/g, and cobalt ferrites have a magnetization of 19.14 emu/g. Moreover, the squareness (0.263) and coercivity (716.15 G) of cobalt ferrite are higher than those of copper ferrite.

Thermal transformation of bamboo sawdust for its advanced cementitious composites

This paper investigates a vacuum heat treatment (VHT) technology at 160℃, 200℃ and 240℃ for 6–14 h to modify bamboo sawdust (BS) and then BS/cement composites for the development of low carbon construction materials. The hydration process, thermal stability, micro-morphology and crystallinity, and chemical and mechanical changes for both VHT BS and composites are examined by FTIR, TG-DTG, XRD and SEM analyses. The mechanism of improving the mechanical properties of modified BS on composite materials is further elaborated together with the physical and mechanical properties and durability. The results show that the flexural strength and compressive strength of the modified BS/cement composites after VHT at 200℃ for 10 h are increased by 61.2% and 13.8%, respectively, compared with those in the untreated group, and the composites have better durability in the modified group. VHT resulted in cellulose and hemicellulose degradation to certain degrees, lignin undergoes cross-linked condensation reaction and cellulose crystallinity increases. These changes reduce the number of BS hydrophilic groups and result in changes in BS microstructure and surface topography, providing favorable conditions for the bonding and interface development of BS/cement composites. The impact of BS/cement composites on the carbon footprint in the production stage was analyzed, showing that the carbon emissions of BS/cement composites after VHT were reduced by 5.7% compared with that of the corresponding OPC composites.

A novel Schiff base ligand and its metal complexes: Synthesis, characterization, theoretical calculations, catalase-like and catecholase-like enzymatic activities

In this study, a new Schiff base (H2L), which has not been recorded in the literature, and its metal complexes with general formula [ML].(H2O) [M: Cu(II) and Mn(II)] were synthesized and their structures were elucidated. Techniques such as 1H- and 13C-NMR, FT-IR, UV–vis, TG-DTG, molar conductivity, magnetic susceptibility, ICP-OES, and elemental analysis were used to characterize the structures of the Schiff base and metal complexes. According to the analysis's findings, the complexes' metal:ligand ratio was 1:1. Additionally, the 6-311G(d,p) and LANL2DZ basis sets of the DFT/B3LYP method were used to calculate the optimized molecular geometries of the H2L and its metal complexes, respectively. Additionally, the synthesized compounds' molecular electrostatic potential (MEP) diagrams, frontier molecular orbitals (HOMO-LUMO), chemical shift values for the 1H- and 13C-NMR, vibrational frequencies, and wavelengths of electronic transitions were all determined. Experimentally obtained results were verified with theoretical data that matched well. [CuL].(H2O) and [MnL].(H2O) were examined for their catalase-like and catecholase-like enzymatic activities using volumetric and spectrophotometric techniques, respectively. For this objective, the catalytic activities of the synthesized molecules in the disproporsion reaction of H2O2 in the presence of 1-methylimidazole and the oxidation reaction of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone in aerobic medium were investigated. According to the enzyme-like studies, [MnL].(H2O) was more catalytically active than [CuL].(H2O) in both of the mentioned reactions.

Thermal and mass spectrometer analysis (TG - DTG - MS) of different oAPI gravity crude oils from new oil fields in Turkey

In this research, thermal analysis and kinetics of four different crude oil samples (oAPI range of 21.1–34.1) from different new oil fields of Turkey were studied using thermogravimetry (TG-DTG) coupled with a quadruple mass spectrometer (MS). Mixtures of crude oils and limestone matrix are prepared to give a composition of 15 % wt. crude oil in the matrix and the ramped temperature experiments are performed at different heating rates (10, 20 and 30 °C/min) under air atmosphere. In TG-DTG analysis three different reaction regions were observed, known as low temperature oxidation (LTO), fuel deposition (FD), high temperature oxidation (HTO) and finally limestone decomposition, respectively. In MS analysis, combustion products of different crude oils on the basis of both relative intensities and relevancy was monitored simultaneously. Finally, two different model free kinetic methods known as Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) were used to determine the activation energy of the crude oil samples. It was observed that the activation energy values are varied between 189.47 and 290.41 kJ/mol (OFW method) and 181.75–288.37 kJ/mol (KAS method) in HTO region, respectively.