Thermogravimetry And Derivative Thermogravimetry Research Articles

The MIL100(Fe)/BaTi0.85Zr0.15O3 nanocomposite with the photocatalytic capability for study of tetracycline photodegradation kinetics

The visible light-active nanocomposite with the photocatalytic capability was facile one-pot solvothermal method successfully synthesized. X-ray diffraction (XRD), Thermogravimetry and Derivative Thermogravimetry (TG-DTG), Scanning Electron Microscopy with Energy Dispersive X-ray Analysis (SEM-EDX), Diffuse Reflectance Spectroscopy (UV–Vis DRS), and Fourier Transform Infra-Red (FT-IR) analysis were employed to characterize the synthetized BaTi0.85Zr0.15O3, MIL-100(Fe), and the MIL-100(Fe)/BaTi0.85Zr0.15O3 samples. As a result of the Scherrer equations, the size of grains for MIL-100(Fe), BaTi0.85Zr0.15O3, and MIL-100(Fe)/BaTi0.85Zr0.15O3 was estimated to be 40.81, 12.00, and 22.70 nm, respectively. MIL-100(Fe), BaTi0.85Zr0.15O3, and MIL-100(Fe)/BaTi0.85Zr0.15O3 samples showed bandgap values of 1.77, 3.02, and 2.56 determined from their absorption edge wavelengths. In the photodegraded solutions, chemical oxygen demand (COD) data and tetracycline (TC) absorbencies were used to obtain the rate constants of 0.032 min−1 and 0.030 min−1, respectively. This corresponds to t1/2-values of 27.7 min and 21.7 min, respectively, for the degradation and mineralization of TC molecules during photodegradation process.

Carbonation properties of dredged slurry pre-dried with steel slag powder: Effects of clay minerals and organic acids

The carbonation properties of dredged slurry pre-dried with steel slag powder were investigated in this study, and steel slag powder was also involved in the drying process. However, it remains unclear how the interaction between steel slag and clay minerals or organic acids in the slurry affects the carbonation performance of the dried soil (DS), and the underlying mechanism needs elucidation. In this study, quartz, montmorillonite, and fulvic acid (FA) were used to prepare five types of artificial soil testing samples. The artificial soils were then made into slurry and dried using steel slag powder to obtain DS. The carbonated soil (CS) was attained by carbonation stabilization/solidification (S/S) of DS, and the effect of montmorillonite and/or FA on the optimal moisture content for carbonation (C-OMC) and the strength ratio of carbonation (Rcs) of the CS were evaluated by unconfined compressive strength. In addition, the mixed soil (MS), as the reference group of DS, was prepared by combining artificial dry soil directly with steel slag to help understand how the interaction between montmorillonite or FA and steel slag during the drying process. X-ray diffraction (XRD), thermogravimetry and derivative thermogravimetry (TG/DTG), and pH tests were used to characterize the changes of microscopic mineral and pH value during the drying process from MS to DS, and the carbonation process from DS to CS. The results showed that the existence and content of montmorillonite can reduce the carbonation efficiency of DS, and a small amount of FA is conducive to improving the carbonation efficiency of DS. By comparing the composition changes of DS and MS, it was confirmed that the interaction between steel slag and montmorillonite or FA existed in the drying process, and this interaction affected the carbonation performance of DS by changing the pH value of DS.

Mechanical and Microstructural Characteristics of Calcium Sulfoaluminate Cement Exposed to Early-Age Carbonation Curing.

The early-age carbonation curing technique is an effective way to improve the performance of cement-based materials and reduce their carbon footprint. This work investigates the early mechanical properties and microstructure of calcium sulfoaluminate (CSA) cement specimens under early-age carbonation curing, considering five factors: briquetting pressure, water–binder (w/b) ratio, starting point of carbonation curing, carbonation curing time, and carbonation curing pressure. The carbonization process and performance enhancement mechanism of CSA cement are analyzed by mercury intrusion porosimetry (MIP), thermogravimetry and derivative thermogravimetry (TG-DTG) analysis, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results show that early-age carbonation curing can accelerate the hardening speed of CSA cement paste, reduce the cumulative porosity of the cement paste, refine the pore diameter distribution, and make the pore diameter distribution more uniform, thus greatly improving the early compressive strength of the paste. The most favorable w/b ratio for the carbonization reaction of CSA cement paste is between 0.15 and 0.2; the most suitable carbonation curing starting time point is 4 h after initial hydration; the carbonation curing pressure should be between 3 and 4 bar; and the most appropriate time for carbonation curing is between 6 and 12 h.

Functionalization of SBA-15 with EDTA and its application in removing Ca2+ and Mg2+ ions from hard water

O mau gerenciamento, as mudanças nos parâmetros de consumo e a seca sujeitam muitas partes do mundo à sobrevivência diante da escassez de água potável e a qualidade da água potável precisa ser avaliada para um consumo adequado. A água dura pode levar ao acúmulo de depósitos minerais em tubulações e aparelhos que usam água regularmente, afetando o desempenho e o ciclo de vida desses itens. Além disso, na presença de sabão, os ácidos graxos formam um precipitado insolúvel com íons cálcio, dificultando a espuma e a limpeza, além de outros problemas gerados pelo alto conteúdo dos íons Ca2+ e Mg2+ presentes na água. O objetivo deste trabalho foi estudar a remoção dos íons Ca2+ e Mg2+ usando a SBA-15, um material mesoporoso, funcionalizado com ácido etilenodiaminotetracético e comparado à sua matriz pura. Este adsorvente foi testado em solução de íons Ca2+ e Mg2+ com concentração de 250 mg.L-1 e pH 9, variando a temperatura em 25°C e 50°C. Os materiais mesoporosos foram sintetizados pelo método hidrotérmico e caracterizados por TG-DTG (Termogravimetria e Termogravimetria Derivada), DRX (Difração de Raios X) e BET (método Brunauer, Emmett, Teller). Os resultados da adsorção mostraram uma remoção de até 50% dos íons Ca2+ e Mg2+ em um curto período de tempo, aproximadamente 5 min.

Study of the Effect of Injection Currents on White Light Emission of Ce-Doped YAG Phosphor Powder Prepared by Microwave Combustion

The behaviors of yttrium aluminum garnet (YAG) phosphor powder doped by cerium (YAG:Ce3+) was studied. Here, the YAG:Ce3+ nanopowders have been synthesized using microwave combustion (MW) according to the formula, Y(3-0.04) Al5O12: 0.04Ce3+ to produce white light emitting diode (WLEDs) by conversion from blue indium gallium nitride light emitting diode (InGaN LED, 445 nm) chips; the whole process took only 20 min. Pure YAG phase was obtained after annealing at 1050 °C for 5 h with nonaggregated and spherical particles. Thermogravimetry and derivative thermogravimetry (TG/DTG), X-ray powder diffraction (XRPD), transmission electron microscope (TEM), photoluminescence (PL), electroluminescence (EL) emissions and standard CIE 1931 chromaticity diagrams have been used to characterize the samples. The highest WLEDs emission was achieved for the annealed YAG:Ce3+, together with proper color rendering index (CRI), and tunable correlated color temperature (CCT). Finally, we conclude that the decreasing EL intensity at increased injection current is caused by the thermal ionization from the 5d1 level to the conduction band.

A comparison of chitosan properties after extraction from shrimp shells by diluted and concentrated acids

Chitosan and chitin are mainly extracted from shells of fish such as lobsters, crabs or shrimps. Originally, the raw material and the two compounds are identical. This study aims to show the acid concentration effect on chitosan extraction from shrimp shells between concentrated and diluted acid; on surface morphology, thermal resistance, structural, elemental composition, optical and opto-electronic properties. It also aims to reduce the production time and increase the quantity. We focused mainly on comparing between Physico-chemical properties of chitosans extracted by diluted (1M) and concentrated (20%) Chloric acids, and sometimes we compare by other concentrated acids like nitric acid (70%) and sulphuric acid (98%). We performed the product's characterization by various tools such as: X-ray diffraction (XRD) spectroscopy, X-ray fluorescence (XRF) analysis, UV-Visible spectroscopy, Fourier Transformed Infra-Red (FTIR), Raman Spectroscopy, Thermogravimetry and Derivative Thermogravimetry (TG/DTG), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) analysis. The elemental analysis (XRF and EDX). The results showed that all chitosan samples we gained are good about 80% degree of deacetylation, and pure mostly composed by carbon between (15,02% - 45.55%), nitrogen (4,17% - 12.28%) and oxygen (42.16% and 81.25%), with appearance of essential peaks for chitosan in Raman analysis: 470 cm−1 → ν(C-C(=O)-C), 1000 cm−1 → ν(C-H), 1800 cm−1 → δ(C=CCOOR), δ(C=O), 2630 cm−1 → δ(CH) rings, 3250 cm−1 → ν(NH2). All our chitosan particles are ultrafine nanoscale between 8 and 34 nm.

Elimination of Phenylhydrazine from Aqueous Solutions by Use of a Photocatalyst Prepared by Immobilization of TiO2 on Polypyrrole Support

In this study, a nano photocatalyst was prepared by immobilization of TiO2 on the surface of polymerized pyrrole. The photocatalyst was characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FT-IR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and Thermogravimetry and Derivative Thermogravimetry (TG-DTG) techniques. Diffuse Reflectance Spectroscopy (DRS) and Photoluminescence (PL) analysis were employed to study the optical property of the photocatalyst. The synthesized photocatalyst was then employed for degradation of phenylhydrazine (PHZ). The effect of various experimental parameters including; initial pollutant concentration, irradiation time, pH and catalyst dose was studied. The results indicated that degradation efficiency of the synthesized photocatalyst was much higher than bulk TiO2, and the degradation efficiency of 45 and 75% was respectively obtained for bulk TiO2 and the synthesized photocatalyst. DRS results indicated that the band gap of TiO2 was significantly shifted to lower energy after loading on polypyrrole (PPy). The PL analysis showed that the electron–hole recombination in the synthesized photocatalyst was much lower than TiO2. The used photocatalyst regenerated by thermal treatment retained most of its initial activity.

THERMOANALYTICAL STUDY OF ACECLOFENAC FORMULATIONS WITH REGULAR MAIZE STARCH AND WAXY MAIZE STARCH

Production of tablets in pharmaceutical industry often is required to mixture the active ingredient (drug) with an inert material. Starch is shown as a good alternative material to be used as excipient. Thus, in this investigation the techniques: thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC as well as thermomicroscopy were performed with aim to verify existence of interactions between aceclofenac (2-[2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetyl]oxalacetic) with regular maize starch and waxy maize starch. Binary and physical mixtures of aceclofenac and starch in ratios 2:1, 1:1 and 1:2 (drug:starch) studied by the instrumental techniques showed that no interactions occurs between the drug and starches in any ratio, being maintained the properties of aceclofenac.

Synthesis, characterization, thermal, electrical and magnetic properties of polyaniline composites with rare earth gadolinium coordination complex

Novel polyaniline/gadolinium (PANI/Gd) composites were successfully synthesized by “in‐situ” polymerization at the presence of rare earth Gd coordination complex and D‐tartaric acid (an a dopant). It is rarely to find the studies on related field to add rare earth Gd coordination complex as fillers. Fourier transform infrared (FTIR) spectra, X‐ray diffraction (XRD) and scanning electron microscope (SEM) were used to examine the structure and surface appearance characterization of materials. The thermal stability performance of composites was investigated by thermogravimetry and derivative thermogravimetry (TG‐DTG). Electrochemical performance was measured by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge test. The magnetic property was investigated by physical property measurement system (PPMS). The structure and surface appearance characterization and the magnetic properties jointly demonstrate the polymerization of rare earth Gd coordination complex and PANI–D‐tartrate (DTA) not only simple physical mixing but also chemical mixing. TG‐DTG analysis suggests that thermal stability of PANI/Gd composites is higher than that of PANI–DTA. Electrochemical performance tests and SEM indicate that the composite (PANI/Gd = 3.3:1,mass ratio) has the most regular morphology and best specific capacitance. The magnetization of the composite (PANI/Gd = 3.3:1,mass ratio)is evidently smaller compared with PANI–DTA and rare earth Gd coordination complex. Copyright © 2016 John Wiley & Sons, Ltd.

Preparation of a novel chitosan-microcapsules/starch blend film and the study of its drug-release mechanism

A novel drug delivery system, chitosan-microcapsules/starch blend film for antofloxacin controlled release, was prepared, and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (X-RD), thermogravimetry and derivative thermogravimetry (TG/DTG), and scanning electron microscopy (SEM). Following incorporation of the chitosan-microcapsules in the film matrix, the synergistic interactions between these drug-carriers were significant. The thermostability and mechanical properties of the blend film were greatly improved by the incorporation of the microcapsules. The water resistance of the blend film was enhanced by increasing the content of microcapsules, indicating that the microcapsules acted as moisture barriers. After being incorporated, chitosan-microcapsules/starch blend film shows a sustained drug release. The extent of the film degradation and microcapsules swelling in the release system indicated that the drug released of the blend film was pH-sensitive. The blend film exhibited pharmacodynamic efficacy because of the efficient drug releasing.

Ammonia-Alkali Solution Coordination-Precipitation Route for Preparation of β-Ni(OH)2 Nano-Particles

Abstract Nano-sized nickel hydroxide particles were synthesized at room temperature by a facile coordination precipitation method, through simply dropping sodium hydroxide solution to dissociate the complex of nickel-hexammonia, using nickel chloride, ammonia and sodium hydroxide as raw materials. Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetry and derivative thermo-gravimetry (TG-DTG), X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were used to characterize the products. It is demonstrated that the product is pure β-type nickel hydroxide, which contains more nickel and fewer intercalated anions comparatively, and likely boosts its electrochemical activity. The average size of β-type nickel hydroxide nano-particles is about 100 nm.

Adsorption behaviors of thiophene, benzene, and cyclohexene on FAU zeolites: Comparison of CeY obtained by liquid-, and solid-state ion exchange

Cerium containing Y zeolites were prepared by liquid- (L-CeY) and solid- (S-CeY) state ion exchange from NaY and HY, respectively. The structural and textural properties were characterized by XRD and N2 adsorption, and acidity properties were characterized by NH3 temperature-programmed desorption (NH3-TPD) and in situ FTIR spectrum of chemisorbed pyridine (in situ Py-FTIR). Furthermore, the single component adsorption and multi-component competitive adsorption behavior of thiophene, benzene and cyclohexene on those zeolites have also been studied by using vapor adsorption isotherms, solution adsorption breakthrough curves, thermogravimetry and derivative thermogravimetry (TG/DTG), frequency response (FR) and in situ FTIR techniques. The results indicate that the primary adsorption mode of benzene is simply micropore filling process, but the nature of effect of aromatics on selective adsorption of thiophene is competitive adsorption. The strong chemical adsorptions and protonization reactions of thiophene and cyclohexene occur upon the Brönsted acid sites of the HY and L-CeY zeolites, and the preferable acid catalytic protonization reactions of olefins hinder the further adsorption of sulfur compounds.

Effects of heat–moisture treatment on organic cassava starch

Organic foods and crops are produced throughout the world under strict controls on growing conditions, so that synthetic chemicals, irradiation or genetic modifications are avoided. Organic starch is extracted following the same rules. Heat–moisture treatment (HMT) on starch is a physical method considered to be natural: it consists of heating starch at a temperature above its gelatinisation point with insufficient moisture (<35 %) to cause gelatinisation. Samples of organic cassava starch (with 12.8 % moisture) were dried in an oven with forced air circulation at 50 °C for 48 h and, immediately, distilled water was added to each sample until it reached the ratios of 10, 20, and 30 %, respectively. The samples were transferred into 100 mL pressure flasks, sealed tightly with a cap, and maintained in an autoclave for 60 min at 120 °C. The flasks were opened and the samples were kept in a desiccator containing anhydrous calcium chloride up to constant mass. The effects of HMT were studied using the following techniques: thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), rapid viscoamylographic analysis (RVA), reflectance photocolorimetry, atomic force microscopy (NC-AFM) and X-ray diffractometry (XRD). Rheological properties such as the pasting temperature (RVA) and the peak temperature (DSC) increased, while gelatinisation enthalpy ∆H (DSC) decreased. The average diameters of the granules showed no significant changes, while the degree of relative crystallinity decreased.

The Research on the Disperse Form of PEO Fiber by Electrostatic Spinning Method

We prepared PEO nano fiber with different concentration of PEO acid solution by electrostatic spinning in different technology conditions. Then we studied the property of solution by rotary viscometer instrument and electrical conductivity spectrometer, the disperse form of the fiber by SEM scattered forms, the thermal property of the composite was studied by thermogravimetry and derivative thermogravimetry (TG-DTA). The conclusion is the disperse form of fiber is controlled by the concentration of solution, the voltage of spinning, the distance of solidification. The important factor is about the solution. To increase the solution viscosity and the solidification distance, reduce the spinning voltage would decrease the diameter of the fiber. Thermal stability of fiber was significantly better than powder.

Fluorescence enhancement of Tb(III) complex with a new β-diketone ligand by 1,10-phenanthroline

A novel β-diketone, 1-(3,4,5-trisbenzyloxy)benzoyl-5-benzoyl acetylacetone (TBAA), and its corresponding binary Tb(III) complex Tb(TBAA) 3·2H 2O and ternary complex Tb(TBAA) 3Phen with 1,10-phenanthroline (Phen) were prepared. The ligand was characterized based on elemental analysis, FT-IR, and 1H NMR. The complexes were characterized with elemental analysis, FT-IR and thermogravimetry and derivative thermogravimetry (TG-DTG). Photoluminescence measurements indicated that the energy absorbed by the organic ligand was efficiently transferred to the central Tb 3+ ions, and the complex showed intense and characteristic emissions due to the 5D 4→ 7F J transitions of the central Tb 3+ ions. Both complexes showed longer fluorescence lifetimes. After the introduction of the second ligand Phen group, the relative emission intensities and fluorescence lifetimes of the ternary complex Tb(TBAA) 3Phen enhanced more obviously than that of the binary complex Tb(TBAA) 3·2H 2O. This indicated that the presence of the ligand TBAA and the second ligand Phen could sensitize fluorescence intensities of Tb(III) ions, and the introduction of Phen group resulted in the enhancement of the fluorescence properties of the Tb(III) ternary rare earth complex.

Synthesis, characterization and thermal behaviour on solid pyruvates of some bivalent metal ions

Solid state M-L compounds, were M stands for bivalent Mn, Fe, Co, Ni, Cu, Zn and L is pyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), X-Ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, ligand denticity, and thermal decomposition of the isolated compounds.

Synthesis, characterization and thermal behaviour of heavy lanthanide and yttrium pyruvates in the solid state

Solid-state Ln–L compounds, where Ln stands for heavy trivalent lanthanides or yttrium (III) (Tb–Lu, Y) and where L is pyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), X-Ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal behaviour, ligand denticity of the isolated complexes.

Thermal decomposition mechanism and quantum chemical investigation of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO)

The thermal decomposition mechanism of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) compound was studied by means of differential scanning calorimetry (DSC), thermogravimetry and derivative thermogravimetry (TG-DTG), and the coupled simultaneous techniques of in situ thermolysis cell with rapid scan Fourier transform infrared spectroscopy (in situ thermolysis/RSFTIR). The thermal decomposition mechanism is proposed. The quantum chemical calculation on HNTO was carried out at B3LYP level with 6-31G+(d) basis set. The results show that HNTO has two exothermic decomposition reaction stages: nitryl group break first away from HNTO molecule, then hydrazine group break almost simultaneously away with carbonyl group, accompanying azole ring breaking in the first stage, and the reciprocity of fragments generated from the decomposition reaction is appeared in the second one. The C–N bond strength sequence in the pentabasic ring (shown in Scheme 1) can be obtained from the quantum chemical calculation as: C3–N4 > N2–C3 > N4–C5 > N1–C5. The weakest bond in NTO− is N7–C3. N11–N4 bond strength is almost equal to N4–C5. The theoretic calculation is in agreement with that of the thermal decomposition experiment. Open image in new window Scheme 1 Scheme of HNTO

Synthesis, characterization and thermal behaviour on solid pyruvates of some bivalent metal ions

Solid state M-L compounds, were M stands for bivalent Mn, Fe, Co, Ni, Cu, Zn and L is pyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), X-Ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, ligand denticity, and thermal decomposition of the isolated compounds.

Synthesis, characterization and thermal behaviour on solid pyruvates of light trivalent lanthanides

Solid State Ln-L compounds, where Ln stands for light trivalent lanthanides(La – Gd) and L is pyruvate, have been synthesized. Thermogravimetry and derivative thermo-gravimetry (TG/DTG), differential scanning calorimetry (DSC), X-Ray powder diffractometry,infrared spectroscopy, elemental analysis, and complexometry were used to characterize and to studythe thermal behaviour of these compounds. The results led to information about the composition, dehy-dration, ligand denticity, thermal behaviour and thermal decomposition of the isolated compounds.