Differential Scanning Calorimetry Thermogravimetric Analysis Research Articles

Inferring changes in soil organic matter in post-wildfire soil burn severity levels in a temperate climate

Simple, rapid and reliable methods of assessing soil burn severity (SBS) are required in order to prioritize post-fire emergency stabilization actions. SBS proxies based on visual identification and changes in soil organic matter (SOM) content and quality can be related to other soil properties in order to determine the extent to which soil is perturbed following fire. This task is addressed in the present study by an approach involving the use of differential scanning calorimetry-thermogravimetric analysis (DSC-TGA) to determine changes in SOM generated in soils subjected to different levels of SBS.Intact topsoil monoliths comprising the organic horizons and the surface mineral soil (alumic-humic umbrisols) were collected from a representative P. pinaster stand in NW Spain. The monoliths were experimentally burned in a combustion wind tunnel to simulate different fire conditions (fuel bed comprising forest pine litter and wood; air flow, 0.6 m s−1). Changes in OM properties in the soil organic layer and mineral soils samples (0–2 cm) at the different temperatures and SBS levels were identified.For both duff and mineral soil, the data revealed a temperature-induced increase in aromatic compounds and a concomitant decrease of carbohydrates and alkyl products. However, for a given temperature, the degree of carbonization/aromatization was lower in the mineral soil than in the duff, possibly due to the different composition of the OM and to the different combustion conditions. The low degree of aromatization of the organic matter suggests that this soil component could undergo subsequent biological degradation. SOM content and thermal recalcitrance (measured as T50) discriminated the SBS levels. Use of visual identification of SBS levels in combination with DSC-TGA enables rapid evaluation of the spatial variability of the effects of fire on SOM properties. This information is useful to predict soil degradation process and implement emergency soil stabilization techniques.

New Conduct in the Adsorptive Removal of Sulfur Compounds by New Nickel–Molybdenum Adsorbent

The article states the first preparation of NiMo layered double hydroxide (LDH) adsorbent for the removal of dibenzothiophene (DBT) form n-heptane solution and desulfurization of gas oil. The existence of (Mo6+) in Ni2+Mo6+ LDH was proven by X-ray photoelectron spectroscopy (XPS), while X-ray diffraction and X-ray fluorescence patterns, Fourier transform infrared spectra, scanning electron microscopy images, and differential scanning calorimetry–thermogravimetric analysis and Brunauer–Emmett–Teller analysis were applied for the composition and surface characterizations. Experimentally, NiMo LDH exhibited a different conduct in the adsorption elimination of sulfur in the existence of aromatics; the sulfur uptake was increased with the increase of the aromatic content in accordance with its own highly charged surface as a result of the formation of +4 balancing charges between Ni2+and Mo6+ through the brucite layers. The material achieved adsorption capacity of 48.8 mg g–1 sulfur for DBT at 25 °C follows a ...

Antimicrobial Nanocomposites Prepared from Montmorillonite/Ag+/Quaternary Ammonium Nitrate

Nanocomposites of Ag with organic montmorillonite (Ag-OMMT), Ag with montmorillonite (Ag-MMT), and organic montmorillonite (OMMT) were successfully prepared via a one-step solution-intercalated method. Sodium MMT, silver nitrate, and dimethyl octadecyl hydroxy ethyl ammonium nitrate were used as precursors. X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy analyses confirmed that the MMT layers were intercalated, and Ag+ was partly reduced to silver nanoparticles with diameters within 10–20 nm in Ag-OMMT. The decomposition temperature of the organic cations in OMMT and Ag-OMMT increased to 220°C, as revealed by differential scanning calorimetry-thermogravimetric analysis. The antimicrobial activity of the nanocomposites was tested by measuring the minimum inhibitory concentration (MIC) and killing rate. The MICs of Ag-OMMT against Staphylococcus aureus, Escherichia coli, and Candida albicans were 0.313, 2.5, and 0.625 mg/mL, respectively. Because of the presence of quaternary ammonium nitrate, Ag-OMMT has a better MIC against Gram-positive bacteria compared to Gram-negative bacteria and fungi. OMMT did not show antimicrobial activity against Escherichia coli and Candida albicans. In 2 h, 0.0125 mg/mL Ag-OMMT could kill 100% of S. aureus, E. coli, and C. albicans in solution, and Ag-MMT could kill 99.995% of S. aureus, 90.15% of E. coli, and 93.68% of C. albicans. These antimicrobial functional nanocomposites have the potential for application in the area of surface decoration films.

Excellent Surface Enhanced Raman Scattering of SiO2 Fiber Membrane Embedded with Ag Nanoparticles

Uniformly distributed Ag nanoparticles supported on SiO2 fiber membrane materials were successfully synthesized using electrospinning and pyrolysis. In this study, the electrostatic spinning solution is composed mainly of polyvinyl pyrrolidone, ethyl silicate (TEOS) and AgNO3. The structural and morphological studies of the materials after calcination were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM) and thermogravimetric analysis–differential scanning calorimetry (TG–DSC). The results indicated that the samples had a rough surface structure. The load on the nanofibers was silver (Ag) metal, and the number and grain size of Ag nanoparticles increased as the relative amounts of AgNO3 increased. Furthermore, the surface enhanced Raman scattering (SERS) activity of the Ag/SiO2 was investigated using the common antibiotic enrofloxacin as a probe. It was found that the amorphous silica fiber with uniform loading of Ag nanoparticles exhibited a strong SERS enhancement effect. Due to the analytical performance, the predicted potential for SERS detection of trace antibiotics is excellent.

Fabrication of porous and magnetic Fe/FeNX fibers by electro-blown spinning method for efficient adsorption of Cr (VI) ions

A novel porous and magnetic Fe/FeNX composite fibers for Cr (VI) ions adsorbent were prepared by electro-blown spinning technology coupled with high temperature nitrided way. The X-ray Diffraction (XRD) and Differential Scanning Calorimetry-Thermo Gravimetric Analyzer (DSC-TGA) revealed metallic iron and FeNX mainly existed in these fibers. Furthermore, the effect of spinning voltage, air pressure and solution concentration on the morphology for the as-spun fibers were investigated. Meanwhile, the effect of calcination temperature on morphology and structure, crystalline property and hysteresis loop also were discussed. The obtained fibers had a uniform morphology and structure, and a high specific surface area (151 m2 g−1) during the calcination temperature of 800 °C. The Fe/FeNX fibers showed effective sorption affinity for Cr (VI) ions, achieving maximum adsorption capacities of 79.21 mg/g at 25 °C. It mainly was ascribed to the existence of metallic iron in the obtained fibers. Meanwhile, the FeNX contents in the fibers were extremely beneficial to the adsorbent recovery.

Preparation of porous Ti2O3 via a carbothermal reduction of titanium dioxide

Porous Ti2O3 was prepared via the carbothermal reduction of titanium dioxide using acetylene black or activated carbon as the reducing agent. The process was carried out at 1300–1350°C in a flowing argon atmosphere or vacuum. The reduced sample had a carbon content of less than 0.007% and a Ti2O3 content of more than 98% when 6.98% acetylene black or 8.88% activated carbon was used as the reducing agent. The pore diameter, pore volume, and porosity of the sample prepared using 6.98% acetylene black were estimated to be 1–3µm, 0.115–0.133cm3g−1, and 39–45%, respectively; those of the sample reduced using 8.88% activated carbon were 7–11µm, 0.165–0.190cm3g−1, and 62–71%, respectively. The kinetic parameters of the carbothermal reduction of TiO2 were investigated using thermogravimetric analysis-differential scanning calorimetry in a flowing Ar atmosphere.

Unprecedented Concomitant Formation of Cu2O-CD Nano-Superstructures During the Aerobic Oxidation of Alcohols and Their Catalytic Use in the Propargylamination Reaction: A Simultaneous Catalysis and Metal Waste Valorization (SCMWV) Method.

Copper–cyclodextrins (CDs)-catalyzed aerobic oxidation of alcohols under aqueous conditions and a concomitant formation of Cu2O–cyclodextrin nano-superstructures (Cu2O–CD nps) during the reaction are reported. The use of affordable copper and cyclodextrin combination for aerobic oxidation precluding organic solvents makes it a benign methodology. Intriguingly, a diverse array of Cu2O–CD nps with unique morphologies was obtained by varying copper salts, cyclodextrins, and bases. The nano-superstructures were characterized by different techniques, such as X-ray diffraction, X-ray photoelectron spectroscopy, differential scanning calorimetry-thermogravimetric analysis, scanning electron microscopy, time of flight secondary-ion mass spectrometry, and transmission electron microscopy to confer their authenticity. Interestingly, the nano-superstructures showed promising catalytic efficiency for a one-pot three-component propargylamination reaction. The used particles were found to be recoverable and recyclable for propargylamination for up to three cycles, with no loss of catalytic activity. Moreover, the concomitant formation of Cu2O–CD nanostructures and their self-segregation during an aerobic oxidation reaction under homogenous conditions is a first-of-its-kind method depicting simultaneous catalysis and metal waste valorization (SCMWV). Overall, this new approach of reaping the benefits of homogenous metal catalysis and simultaneously sequestrating the metal into a high-value product might pave the way to develop many such SCMWV protocols in future.

Preparation of antibacterial temperature‐sensitive silver‐nanocomposite hydrogels from N‐isopropylacrylamide with green tea

ABSTRACTThis article reports the temperature‐sensitive, green tea (GT)‐based silver‐nanocomposite hydrogels for bacterial growth inactivation. The temperature‐sensitive hydrogels were prepared via free‐radical polymerization using temperature‐sensitive N‐isopropylacrylamide (NIPAM) monomer with GT as the hydrogel matrix. The nanocomposite hydrogels were encapsulated with silver ions via swelling method, which was later reduced to silver nanoparticles using Azadirachta indica leaf extract. The temperature‐sensitive silver nanocomposite hydrogels were analyzed by using Fourier transforms infrared, UV–visible spectroscopy, differential scanning calorimetry–thermogravimetric analysis, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The prepared hydrogels exhibited higher phase volume transition temperature than the NIPAM. The inhibition zone study of the inactivation of bacteria on the developed hydrogels was carried out against Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus), which revealed that the prepared hydrogels are helpful for the inactivation of these bacteria due to the high stabilization of antibacterial properties of the silver nanoparticles. The developed hydrogels are promising for biomedical applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45739.

Impact of grain size and structural changes on magnetic, dielectric, electrical, impedance and modulus spectroscopic characteristics of CoFe2O4 nanoparticles synthesized by honey mediated sol-gel combustion method

In this work CoFe2O4 spinel ferrite nanoparticles were synthesized by honey mediated sol-gel combustion method and further annealed at higher temperature 500 °C, 700 °C, 900 °C and 1100 °C. The synthesized spinel ferrite nanoparticles is investigated by x-ray diffraction, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), field emission scanning electron microscopy, x-ray photoelectron spectroscopy and vibrating sample magnetometer. The x-ray diffraction study reveals face-centered cubic spinel cobalt ferrite crystal phase formation. The crystallite size and lattice parameter are increased with annealing temperature. Raman and Fourier transform infrared spectra also confirm spinel ferrite crystal structure of synthesized nanoparticles. The existence of cation at octahedral and tetrahedral site in cobalt ferrite nanoparticles is confirmed by x-ray photoelectron spectroscopy. Magnetic measurement shows increased saturation magnetization 74.4 emu g−1 at higher annealing temperature 1100 °C, high coercivity 1347.3 Oe at lower annealing temperature 500 °C, and high remanent magnetization 32.3 emu g−1 at 900 °C annealing temperature. The magnetic properties of synthesized ferrite nanoparticles can be tuned by adjusting sizes through annealing temperature. Furthermore, the dielectric constant and ac conductivity shows variation with frequency (1–107 Hz), grain size and cation redistribution. The modulus spectroscopy study reveals the role of bulk grain and grain boundary towards the resistance and capacitance. The cole-cole plots in modulus formalism also well support the electrical response of nanoparticles originated from both grain and grain boundaries. The dielectric, electrical, magnetic, impedance and modulus spectroscopic characteristics of synthesized CoFe2O4 spinel ferrite nanoparticles demonstrate the applicability of these nanoparticles for magnetic recording, memory devices and for microwave applications.

Preparation of mono-dispersed carbonaceous spheres via a hydrothermal process

Mono-dispersed carbonaceous spheres (CS) with a narrow size distribution were synthesized via hydrothermal treatment of glucose. The effects of hydrothermal temperature and time, glucose concentration and pH value of solution were investigated in detail. Structures and surface properties of as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Induced coupled plasma emission spectroscopy (ICP), thermogravimetric analysis/differential scanning calorimetry (TG/DSC), Nitrogen adsorption/desorption and Fourier transformed infrared spectroscopy (FTIR). The results showed that the production yield of CS increased from 2.1 to 32% with increasing the temperature from 160 to 180°C, and the average size increased from 0.23 to 0.95μm with extending the hydrothermal time from 8 to 16h. pH value of the starting solution showed an evident effect on the morphology of CS via affecting the decomposition products of glucose. CS could be obtained when the pH value of starting solution was less than 12, but further increasing the pH value to 13–14 led to the formation of lumpy aggregations of carbon rather than spherical CS. The CS prepared under pH 6 and 9 showed good adsorption capacity for Methylene blue (MB), which was attributed to their relatively high specific surface area.

Palladacycle-Catalyzed Triple Suzuki Coupling Strategy for the Synthesis of Anthracene-Based OLED Emitters.

The development of the site-selective Suzuki–Miyaura cross-coupling of dibromoanthracene as an efficient strategy toward organic light emitting diodes (OLEDs) is disclosed in this article. An unprecedented step-economic palladacycle-promoted triple Suzuki coupling protocol allowed the synthesis of three new OLED emitters and could prove to be a useful general strategy for researchers working in this field. Characterization of the synthesized molecules by UV–vis spectroscopy and thermogravimetric analysis–differential scanning calorimetry followed by density functional theory studies of the different properties strongly confirms the derivatives possess more significant hole mobility character than electron transfer capability.

Synthesis, structural, solubility and anticancer activity studies of salts using nucleobases and sulfonic acids coformer

The reactions of natural and unnatural nucleobases (cytosine (Cyt), adenine (Ade), 5-aminouracil (AU) and caffeine (Caff)) with sulfonic acids coformer (1,5-naphthalenedisulfonic acid, NDSA; 5-sulfosalicylic acid, SSA) resulted in the formation of salts viz. [NDSA.Cyt] (1), [NDSA.Ade] (2), [NDSA.AU] (3), [NDSA.Caff] (4), [SSA.Cyt] (5), [SSA.Ade] (6), [SSA.AU] (7), and [SSA.Caff] (8). The structural analysis revealed that salts 1, 4, 6 and 7 have intermolecular interactions between adjacent nucleobases which form two different homodimer shown in R22 (8) motif and assembled via complementary NH⋯O and NH⋯N interactions. However, in all other salts an intermediate supramolecular synthon pattern was observed between nucleobases and sulfonic acids. The lattice energy was also calculated by DFT to investigate whether salts were thermodynamically more stable than its coformer. The same was further confirmed by differential scanning calorimetry-thermogravimetric (DSC-TG) analysis. The anticancer activity study of individual nucleobases and their NDSA salts were also performed on human breast (MCF-7) and lung (A 549) cancer cell. The salts formation of nucleobases with sulfonic acids improved their solubility, thereby demonstrating up to 8-fold increase in solubility of nucleobases.

Thermal degradation behaviour of resins in aluminium composite under isothermal condition

As a member of the aluminium composite, GLARE (GLAss fibre/epoxy REinforced aluminium laminates) was used in the upper fuselage of Airbus A380 because of its superior mechanical properties over monolithic aluminium alloys. Thermal processing is a potential method for materials recycling and reuse from GLARE scrap with the aim of environmental protection and economic benefits. Thermal delamination is a crucial pre-treatment step for GLARE recycling. Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) tests have been used to identify the decomposition temperature range of epoxy resins under non-isothermal condition in our previous work [1]. To obtain an appropriate solution for GLARE thermal delamination, the thermal degradation behaviour of epoxy resins in GLARE under isothermal conditions were investigated and isothermal decomposition kinetic models were built up based on DSC and thermogravimetric analysis TGA. The thermal delamination process of GLARE is determined based on thermal analysis results and experimental optimization.

Fabrication and in vivo evaluation of hydroxyapatite/carbon nanotube electrospun fibers for biomedical/dental application

The aim was to synthesize bioactive electrospun fibers for biomedical and dental application with improved biocompatibility. In situ precipitation of nano-hydroxyapatite (nHA) was performed with various concentrations (0.5%, 1%, 2%, 3%, and 5% wt/wt) of functionalized multi-walled-carbon nanotubes (MWCNTs) by using microwave irradiation technique. The obtained composites were characterized by Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC), and the cylindrical discs were made for mechanical testing. The failure behavior was analyzed by Scanning Electron Microscope (SEM). CNT and HA/CNT were silanized with γ-methacryloxypropyl-trimethoxysilane (MPTS) and mixed with polyvinyl alcohol (10% wt./vol.) and electrospun to fabricate fibers. The biocompatibility of both fibers was accessed by their effects on angiogenesis in a chick chorioallantoic membrane (CAM) assay. The electrospun fibers were analyzed by SEM. FTIR confirmed the structural behavior of pre and post-silanized HA/CNT. XRD showed the phase purity and crystallinity before and after heat treatment. Mechanical properties showed that 3% loaded HA/CNT has higher compressive strength (100.5±5.9MPa) compared to others and the failure behavior exhibited dispersion of CNT in HA matrix. The HA/CNT electrospun fibers showed significantly more blood vessels formation compared to CNT fibers. These HA/CNT electrospun fibers showed promising results in terms of biocompatibility and with improved mechanical properties of CNT reinforced composites, they can be used in load bearing clinical applications.

Investigation of Room-Temperature Ferromagnetism on Pristine and Non-ferromagnetic Dopant-Substituted SnO2 Nanoparticles

Pure and aluminium-doped tin oxide (SnO2) nanoparticles have been successfully synthesized by a sol-gel method. The paper mainly reports an investigation on the effect of a non-ferromagnetic dopant (aluminium) on the magnetic properties of SnO2 nanoparticles. The structural and optical properties were also examined. The as-prepared nanoparticles were characterized using X-ray diffraction (XRD), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), UV-vis spectroscopy and magnetic characterization using a vibrating sample magnetometer (VSM). XRD data revealed the SnO2 phase formation for all the samples, indicating that the growth technique was efficient in diluting aluminium ions in the SnO2 lattice. All the samples exhibited peculiar room-temperature ferromagnetic behaviour. The origin of ferromagnetism in the samples lays around the Al–SnO2 interfaces and vacancy defects.

Catalytic and recyclability properties of phytogenic copper oxide nanoparticles derived from Aglaia elaeagnoidea flower extract

The phytogenic synthesis method to highly active, recoverable and recyclable heterogeneous copper oxide nanocatalyst and encapsulated within biomaterial that acts as a nontoxic and renewable source of reducing and stabilizing agent. The biosynthesized CuO NPs were characterized using UV–Vis absorption spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and thermo gravimetric analysis-differential scanning calorimetry (TGA–DSC), techniques. The formation of CuO NPs with the size 20–45nm range is shown in TEM image. Significantly, in aqueous phase CuO NPs have high catalytic activity for the reduction of Congo red (CR), methylene blue (MB) and 4-nitrophenol (4-NP) in the presence of the sodium borohydride (NaBH4) at room temperature. In addition, CuO NPs catalyst can be easily recovered by centrifugation and reused for 6 cycles with more than 90% conversion efficiency. CuO nanocatalyst, leaching after catalytic application was investigated by ICPAES (Inductively coupled plasma atomic emission spectroscopy). CuO NPs possess great prospects in reduction of pernicious dyes and nitro organic pollutants in water.

Synthesis and characterization of MnO-doped titanium pyrophosphates (Ti1-x Mn x P2O7; x = 0–0.2) for intermediate-temperature proton-conducting ceramic-electrolyte fuel cells

MnO-doped TiP2O7 (Ti1-x Mn x P2O7; x = 0–0.2) were synthesized by digesting oxide precursors with H3PO4 in a two-step synthesis method. Various compositions of Ti1-x Mn x P2O7 were characterized by X-ray diffraction (XRD), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). XRD of 1050 °C sintered samples showed the formation of (TiO)P2O7 in ≥15 mol% MnO-doped samples. SEM images of 1050 °C sintered Ti1-x Mn x P2O7 samples showed that MnO acts as a sintering aid, with the higher amount of MnO leading to a better densification. It was observed that the ionic conductivities of MnO-doped sintered samples were higher than that of undoped TiP2O7 (TiP) sample. The increase in ionic conductivity of MnO-doped TiP2O7 can be attributed to MnO acting as an acceptor dopant, and increased densification of the MnO-doped samples. In unhumidified air, among various MnO-doped samples, Ti0.9Mn0.1P2O7 (TMP10) showed the highest ionic conductivity with a magnitude of 6.29 × 10−8 S cm−1 at 250 °C and 1.33 × 10−5 S cm−1 at 500 °C. Furthermore, the ionic conductivity of TMP10 was higher than that of Ti0.88Mn0.12P2O7 (TMP12), which could be attributed to the formation of defect pairs in TMP12. The ionic conductivity of TMP10 showed >4 orders of magnitude increase in humidified air (pH2O = 0.12 atm) in 100–270 °C range with a maximum of 6.55 × 10−4 S cm−1 at 180 °C. In addition, comparison with the literature data showed that the ionic conductivity of TMP10 was higher than those observed for the high-temperature sintered TiP2O7 samples.

In-situ kerogen extraction via combustion and pyrolysis

The extraction of organic kerogen from the vast oil shale reserves in Green River, Utah is limited owing to the environmental and technical challenges. This study compares the efficiency of combustion and pyrolysis to extract the kerogen from shale, in terms of organic thermal decomposition temperature, heating rates, and activation energy calculations. Samples collected from the Green River formation were first characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Fourier Transform InfraRed (FTIR) Spectroscopy. Thermogravimetric Analyzer/Differential Scanning Calorimetry (TGA/DSC) was used to simulate combustion via air injection and pyrolysis via nitrogen injection. These experiments were carried out with and without addition of water and a catalyst (iron oxide), at three different heating rates. The organic and inorganic composition of the oil shale samples before and after the experiments were determined via FTIR. The effectiveness of the processes was examined by the thermal decomposition temperature of kerogen and activation energy requirement. It has been observed that the combustion process is a more efficient method for the extraction of kerogen from oil shale than the conventional pyrolysis. The addition of water and catalyst to combustion has been found to lower the required temperature for kerogen decomposition for lower heating rate. Combustion and pyrolysis at higher heating rates are found to generate higher amount of heat from the process. This study provides insight for the process optimization of the thermal methods for the kerogen extraction.

ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation

The research work involves the development of better and reliable method for the bio-fabrication of Zinc oxide nanoparticles through green method using Moringa Oleifera extract as an effective chelating agent. The electrochemical activity, crystalline structure, morphology, isothermal behavior, chemical composition and optical properties of ZnO nanoparticles were studied using various characterization techniques i.e. Cyclic voltammetry (CV), X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Selected area electron diffraction (SEAD), Differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared analysis (FTIR) and Ultraviolet spectroscopy studies (UV–vis). The electrochemical analysis proved that the ZnO nano has high electrochemical activity without any modifications and therefore are considered as a potential candidate in electrochemical applications. The XRD pattern confirmed the crystallinity and pure phase of the sample. DSC/TGA analysis of ZnO sample (before anneal) revealed three endothermic peaks around 140.8°C, 223.7°C and 389.5°C. These endothermic peaks are attributed to the loss of volatile surfactant, conversion of zinc hydroxide to zinc oxide nanoparticles and transformation of zinc oxide into zinc nanoparticles. Mechanisms of formation of the ZnO nanoparticles via the chemical reaction of the Zinc nitrate precursor with the bioactive compounds of the Moringa oleifera are proposed for each of the major family compounds: Vitamins, Flavonoids, and Phenolic acids.

Inhibition Effect of Phosphorus Flame Retardants on the Fire Disasters Induced by Spontaneous Combustion of Coal

Coal spontaneous combustion (CSC) generally induces fire disasters in underground mines, thus causing serious casualties, environmental pollution, and property loss around the world. By using six P-containing additives to process three typical coal samples, this study investigated the variations of the self-ignition characteristics of the coal samples before and after treatment. The analysis was performed by combining thermogravimetric analysis/differential scanning calorimetry (TG/DSC) Fourier transform infrared spectrometer (FTIR) and low temperature oxidation. Experimental results showed that P-containing inhibitors could effectively restrain the heat emitted in the combustion of coal samples and therefore the ignition temperature of the coal samples was delayed at varying degrees. The combustion rate of the coal samples was reduced as well. At the temperatures ranging from 50°C to 150°C, the activation energy of the coal samples after the treatment was found to increase, which indicated that the coal samples were more difficult to be oxidized. After being treated with phosphorus flame retardants (PFRs), the content of several active groups represented by the C-O structure in the three coal samples was proved to be obviously changed. This suggested that PFRs could significantly inhibit the content of CO generated by the low temperature oxidation of coal, and the flame-retardant efficiency grew with the increasing temperature. At 200°C, the maximal inhibition efficiency reached approximately 85%.