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The aim of this work was to identify parameters that could influence the conversion of kaolinite into metakaolinite. To this end, the dehydroxylation of four kaolinites, using controlled rate thermal analysis (CRTA) and thermogravimetric analysis (TGA), was investigated. X-ray diffraction (XRD) and Fourier transform infra-red (FTIR) were used to confirm the kaolinitic nature of the samples. Their crystallinity was evaluated using the Hinckley index from the XRD patterns and transmission electron microscopy (TEM) was used for morphological observation of the clay platelets. The thermal analyses of the samples indicate, for all samples, low defects as revealed by the low amount of adsorbed water on the clay surface. The dehydroxylation temperature from both techniques was influenced by the sample crystallinity and particle size. It was observed from both techniques that increase crystallinity resulted in highdehydroxylation temperature. Also, the influence of the clay platelets size on the dehydroxylation temperature, is proposed. All the results indicate that crystallinity and particle size are parameters that could be used to control the temperature for the conversion of kaolinite to metakaolinite. Keywords: Kaolinite; Crystallinity, Dehydroxylation; Thermal analysis

Shea nut shell (SNS) is an agrowaste obtained from Vitellaria paradoxa tree and discarded by burning. The extraction of nanocellulose from this agrowaste is expected to be a value addition to Shea farming and processing. However, the isolation of quality nanocellulose begins with optimal pretreatment of the agrowaste material. In this work, the mercerization of SNS collected from local processing centers was carried out by varying the treatment conditions such as temperature, time, liquor ratio (LR) and concentration of the alkali solution. The resulting samples were characterized using FTIR, TGA and DTGA. From the results obtained, the minimum treatment conditions required to isolate cellulose from SNS was obtained as 100 °C for treatment temperature, 2 h for treatment time, 1:20 for LR and 20% for alkali solution concentration. The isolated cellulose was also found to be of good thermal properties when compared to cellulose from other agrowaste. However, these conditions can be varied to give desired properties for specific application.

Eucalyptus wood is one of the important hardwood resources with attractive properties of rapid growth and good quality, which are widely used for the manufacture of wood-based boards, furniture, pulp and paper, and so on. In order to explore the potential of sawdust waste from the eucalyptus wood furniture factory as a bioenergy feedstock, its pyrolysis properties after different solvent extractions were examined using thermogravimetric analysis coupled with Fourier transform infrared spectrometry. The mass ratio of extractives in eucalyptus wood sawdust by benzene–alcohol, hot water, and sodium hydroxide solution was 4.25, 9.68, and 16.11%, respectively. After extraction, the thermal decomposition process of eucalyptus wood was promoted with a higher weight loss rate, lower activation energy, and lower residue content compared to the raw sample without pretreatment, and the promotion level was positively correlated to the strength of extracting solvent. CO2, CO, CH4, H2O, acids, aldehydes, aromatics, ethers, and alcohols were identified as the important intermediates in pyrolysis vapors, which can be tuned by different extraction pretreatments. In terms of typical gas products, benzene–alcohol enhanced the release of carbon dioxide, and hot water enhanced the water generation from dehydration reactions and slightly increased the production of carbon monoxide, while sodium hydroxide promoted the formation of methane at the early stage under 280 °C and later stage over 460 °C during the pyrolysis of eucalyptus wood. It is believed that the extraction pretreatment can not only obtain the bioactive extractive products but also benefit the pyrolysis process by lowering the energy barrier and tuning the composition of pyrolysis products.

This study investigates the efficacy of a prepared Ni/θ-Al2O3 catalyst during the pyrolytic conversion of Parachlorella kessleri HY-6 and compares the results with non-catalytic conversion. The catalyst was characterized by techniques such as Brunauer–Emmett–Teller (BET) for surface area, acidity, and X-ray powder diffraction (XRD). Isoconversional and combined kinetic methods were used to study the pyrolytic kinetics of the process. Ni/θ-Al2O3 was used at 10, 20, and 30% of the algal biomass. The addition of Ni/θ-Al2O3 facilitated the conversion by lowering the mean activation energy during pyrolysis. The catalytic effect was more pronounced at lower and higher conversions. The presence of the catalyst facilitated the pyrolysis as indicated by the lower value of activation energy and ∆H, and ∆G. Gases evolved during pyrolysis were qualitatively analyzed by FTIR to see the effect of catalyst on evolved gas composition during the pyrolysis process.

This mini review identifies several thermogravimetric analysis (TGA)-based methods for the identification and quantification of different microplastics in both proof-of-concept studies and environmental samples, and highlights method-specific limitations associated with their application. Well-separated and non-overlapping melting peaks are a conditional requirement for the identification and quantification of microplastics using thermogravimetric analysis-differential scanning calorimetry (TGA-DSC). Other TGA-based methods, such as coupled Fourier transform infrared spectroscopy (TGA-FTIR) or mass spectrometry (TGA-MS), as well as thermal extraction desorption-gas chromatography-mass spectrometry (TED-GC-MS), are dependent on the presence of at least one unique thermal degradation product for use as a marker in the identification and quantification process. Varying degrees of time expenditure and complexity of analysis are present within the reviewed methods, with one consistent factor underlying the evaluation: an underutilization of information extracted from the TGA signal itself. As such, in this mini-review, we advocate the development of methods in which stand-alone TGA can be applied towards the chemical identification of microplastics. Although the main hindrance to this is the presence of overlapping thermal transitions, stand-alone TGA has long been used as a routine and robust method for the analysis of polymers, and methods for optimizing the resolution of complex mixtures are available. Current results in literature emphasize the complementarity of analysis methods, and TGA has potential to play a role as a rapid and facile method that can guide the chemical identification of polymers and address needs of current methods.

To evaluate the combustion characteristics of raw or torrefied bamboo wastes and coal blends, the co-firing process determined by cone and pollutant emission was investigated by thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. The results showed that torrefaction improved the fuel properties of bamboo wastes. Torrefied bamboo had a lower volatile fuel ratio, H/C and O/C ratios, pollutant emission and a higher heating value. They further affected the co-firing process of raw or torrefied bamboo and coal. All blends had a lower ignition temperature and a more stable flame than coal. Torrefied bamboo and coal blends had a lower percentage of quality loss, a higher heat release rate (HRR), total heat release (THR) and total smoke release (TSR). With an increase in the proportion of torrefied bamboo in the blends, the HRR, THR, TSR and percentage of quality loss increased. The main pollutant emissions included CO2, CO, SO2 and NO x. All blends of torrefied bamboo and coal had a lower pollutant emission. The optimum blend suggested was 20% torrefied bamboo/80% coal.

The synthesized phases with chemical composition $$\left[ {{\text{M}}^{2 + }_{6} {\text{Al}}_{3} \left( {\text{OH}} \right)_{18} } \right]\left[ {{\text{A}}^{ + } \left( {{\text{SO}}_{4} } \right)_{2} } \right]12{\text{H}}_{2} {\text{O}}$$ (M2+ = Mn, Mg, Zn; A+ = Li, Na or K) were evaluated in relation to their thermal behavior by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). In the shigaite (M2+ = Mn), natroglaucocerinite (M2+ = Zn) and motukoreaite (M2+ = Mg) phases, the TGA measurements indicated that all samples were dehydrated up to 200 °C in two steps, followed by dehydroxylation above 300 °C. After the thermal treatment at 1000 °C, formation of oxides/spinels were observed for the shigaite and natroglaucocerinite phases, while for motukoreaite, oxides, spinels and MgSO4 were detected. XRD indicated a reduction in the basal distance from around 11 A for the fully hydrated phases to around 7 A for the dehydrated phases. The thermal treatments of some samples at 100 °C, 150 °C and 200 °C indicated that in all phases, intercalated sulfate and alkaline metal ions can be dehydrated and rehydrated. As indicated by FTIR, at 200 °C sulfate could be grafted to the layers and at 300 °C, for all the phases, a stable mixture of amorphous materials was obtained, which could not be rehydrated.

Biosolids, the treated and stabilised sewage sludge, was pyrolysed in the presence of naturally occurring minerals in a Thermogravimetric Analyser (TGA). The results were then compared with a synthetic catalyst (i.e., 5% Co/Al2O3). Higher mass loss was observed in TGA in the presence of both minerals and the metal oxide based catalyst when compared to biosolids' alone pyrolysis. The scanning electron microscope (SEM) images confirmed significant morphological changes in the produced biochars while Fourier Transform Infrared (FTIR) spectra corroborated noticeable chemical changes in their structure. The kinetic analyses conducted using a hybrid approach consisting of model-fitting and model-free methods, suggested that there was a reduction in activation energy in the presence of minerals and the catalyst. Overall, it is concluded that minerals despite their low catalytic activity, offer various process and morphological advantages.

Reliable chemical identification of specific polymers in environmental samples represents a major challenge in plastic research, especially with the wide range of commercial polymers available, along with variable additive mixtures. Thermogravimetric analysis-Fourier transform infrared-gas chromatography-mass spectrometry (TGA-FTIR-GC-MS) offers a unique characterization platform that provides both physical and chemical properties of the analyzed polymers. This study presents a library of 11 polymers generated using virgin plastics and post-consumer products. TGA inflection points and mass of remaining residues following pyrolysis, in some cases, proved to be indicative of the polymer type. FTIR analysis of the evolved gas was able to differentiate between all but polypropylene (PP) and polyethylene (PE). Finally, GC-MS was able to differentiate between the unique chemical fingerprints of all but one polymer in the library. This library was then used to characterize real environmental samples of mesoplastics collected from beaches in the U.K. and South Africa. Unambiguous identification of the polymer types was achieved, with PE being the most frequently detected polymer and with South African samples indicating variations that potentially resulted from aging and weathering.

The far-infrared ray (FIR) is one kind of electromagnetic wave employed for numerous bio-interactive applications such as body thermoregulation, infrared therapy, etc. Tuning the FIR-emitting property of the functional textile surface can initiate a new horizon to utilize this property in sportswear or even smart textiles. Ceramic particles were studied for their unique ability to constantly emit FIR rays. The purpose of this research is to characterize the FIR emission properties and the thermogravimetric analysis of ceramic-embedded polyurethane films. For this purpose, ceramic particles such as aluminum oxide, silicon dioxide, and titanium dioxide were incorporated (individually) with water-based polyurethane (WPU) binder by a sonication technique to make a thin layer of film. Significant improvement in FIR emissive property of the films was found when using different ceramic particles into the polyurethane films. Reflection and transmission at the FIR range were measured with a gold integrating sphere by Fourier-transform infrared (FTIR) spectrometer. The samples were also characterized by thermogravimetric analysis (TGA). Different physical tests, such as tensile strength and contact angle measurements, were performed to illustrate the mechanical properties of the films. The study suggested that the mechanical properties of the polyurethane films were significantly influenced by the addition of ceramic particles.

This work deals with the study of kinetic evaluation and pyrolysis of waste milk packets (polyethylene) for oil production. Thermogravimetric analysis (TGA) of waste milk packets was conducted in an inert atmosphere with heating rates of 5, 10 and 20 °C min−1 to analyse its thermal degradation behaviour. Pyrolysis kinetic parameters consist of activation energy and pre-exponentiation factor, and thermodynamic parameters include changes in Gibb’s free energy, enthalpy and entropy which were computed by Kissinger–Akahira–Sunose (KAS), Ozawa–Flynn–Wall (OFW) and Coats–Redfern methods using TGA data. The mean value of activation energy for pyrolysis of waste milk packets computed by KAS and OFW methods was 175.36 and 177.94 kJ mol−1, respectively, and the pre-exponential factors were found to be in the range of 1.37 × 1013–1.54 × 1014 min−1. Thermal pyrolysis of waste milk packets was performed in a semi-batch pyrolysis reactor. The maximum yield of oil was obtained as 45 wt% at pyrolysis temperature of 500 °C. The oil was analysed by ultimate analysis, Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectrometry (GC–MS). Chemical compounds present in oil were mainly paraffins, naphthenes and olefins with carbon number range of C9–C18. The boiling point of oil was found in the range of 63–360 °C.

Different Fe3O4 particles are synthesised with silane and carboxylic acid, surface modified by co-precipitation, and subsequently are characterised by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, laser particle size analyser (LPSA) and thermogravimetric analyser (TG). Based on the LPSA results, Fe3O4 particles are micrometre size due to the experimental condition and modifiers. It is therefore suggested that the vacuum freeze-drying and the long-chain modifiers tend to obtain small size particles. The modifiers density on the surface of Fe3O4 particles is obtained by TG and formula calculation. It is shown that the silane coupling agent is more effective modifier for Fe3O4 particles compared with carboxylic acid. In accordance with the molecular structure and functional group number of carboxylic acids, different carboxylic acids have different modifiers density.

The effects exerted by the adsorption of vapors of a non-polar compound (deuterated benzene) and a polar compound (water) on the surface of Ottawa sand and a sample of reservoir sand (Channel), which was previously impregnated with silicon oil or two kinds of surfactants, (2-hydroxyethyl) trimethylammonium oleate (HETAO) and (2-hydroxyethyl)trimethylammonium azelate (HETAA), were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and thermogravimetric analysis (TGA). The surface chemistry of the sandstone rocks was elucidated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). Terminal surface groups such as hydroxyls can strongly adsorb molecules that interact with these surface groups (surfactants), resulting in a wettability change. The wettability change effect suffered by the surface after treating it with surfactants was possible to be detected by the DRIFTS technique, wherein it was observed that the surface became more hydrophobic after being treated with silicon oil and HETAO; the surface became more hydrophilic after treating it with HETAA.

Several reports exist on the use of natural-oil-based materials as rejuvenators to restore the properties of aged binders—more specifically, regarding their ability to enhance the binders’ low-temperature properties and to reduce their stiffness. Rejuvenators are typically made of low molecular weight constituents which could easily volatilize and thus render the rejuvenated binder thermally unstable. Hence, the study of the thermal stability of rejuvenated binders is of paramount importance. In this research, a binder with a performance grade (PG) of PG58-28 modified with a soybean-derived rejuvenator at 12% by mass is added to an extracted reclaimed asphalt pavement (RAP) binder at a ratio of 1:5 resulting in a rejuvenator dosage rate of 2% by total mass of binder. The PG of the rejuvenated RAP binder is determined using both dynamic shear rheometer and bending beam rheometer. The thermal stability of the rejuvenator and the binders is verified using thermogravimetric analysis (TG). The rejuvenator shows good thermal stability up to a temperature of 302 °C. The RAP binder containing the rejuvenator shows similar thermal stability to the unrejuvenated RAP binder. The evolved gases from the TG analysis are analyzed using Fourier transform infrared (FTIR) to chemically characterize the rejuvenator and the binders. The FTIR spectrum of the rejuvenator reveals characteristic peaks. The intensity of these peaks serves as an indication of the rate of mass loss of the rejuvenator within the rejuvenated RAP binder.

In order to identify a volatile metallo-organic precursor for the deposition of hafnium oxide (HfO 2 ) films for atomic layer deposition (ALD) applications, the evaporative properties of hafnium alkoxides (hafnium isopropoxide, hafnium n -propoxide and hafnium n -butoxide) were investigated using thermogravimetric analysis. These hafnium alkoxide samples were synthesized by the electrochemical method and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance and inductively coupled plasma analysis techniques. The characterization results indicated that the products were 99.997% high-purity hafnium alkoxides and could meet the requirement of purity considering the usage of making HfO 2 gate oxide by ALD. Synthesized samples were subjected to a simultaneous thermogravimetric–differential thermal analysis unit at 10 K min −1 in a dry nitrogen atmosphere flowing at 100 ml min −1 . Benzoic acid was used to calculate a calibration constant, which could then be inserted into a modified Langmuir equation to calculate vapour pressure curves for hafnium isopropoxide and hafnium n -propoxide. Detailed vapour pressure data for the HfO 2 precursor hafnium alkoxides were determined. The vapour pressure curve of hafnium isopropoxide was constructed within the first stage, and calculated to be ln p = 31.157 (±0.200)−13130.57 (±56.50)/T. Hafnium n -propoxide and hafnium n -butoxide were simultaneously undergoing evaporation and decomposition, thus making calculations invalid.

This two-part study firstly investigated Tetraselmis suecica grown in different CO2 (0.04–15% v/v) concentration through indoor and outdoor cultivation systems. A high CO2 concentration led to a high lipid content, and low nitrogen and oxygen content, which are desirable for transport fuel production. Pyrolysis characteristics were investigated by TG-IR and synchrotron IR microscopy. The results show Tetraselmis suecica grown in 10% CO2 had the highest decomposition rate corresponding to more volatile products produced during the main thermal cracking stage and derived from protein-and lipid-corresponding functional groups. Moreover, a high reaction temperature and CO2 concentration resulted in a low retention of surface functional groups. The nitrogen functional groups initially decomposed at a temperature range of 250–300 °C and still remained at 550 °C, while the lipid-corresponding functional groups completely disappeared at a temperature range of 400–500 °C. Besides, the decomposition of chemical components followed the order of carbohydrate, protein and lipid.

In this work, the kinetics of thermal degradation of chitin and chitosan polymers were investigated by means of Fourier Transform Infrared Spectroscopy and thermogravimetric analyses in air atmosphere, under dynamic conditions in the range of 298–873 K. The kinetic parameters, such as the apparent activation energy (E a ) and pre-exponential factor (A) were determined using Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunose (KAS) isoconversional methods. The experimental data were found, in the range of conversion fraction 0.1 f ( α ) = cα m (1− α ) n with the adjusted values of m, n and c. It was found that the simulated curves issued from the model best fit those issued from the experimental data, indicating the same scission mechanism for the degradation of chitin and chitosan. It was found that the average value of E a = 125 kJ/mol used in the simulated curves of chitin, Y (α) and Z (α), is comparable to those calculated by KAS and OFW, while for chitosan, it represents the mean value (E a = 169 kJ/mol) between the values of E a calculated by KAS (E a = 191.61 kJ/mol) and OFW (E a = 146.50 kJ/mol) methods.

Objective: Zinc chloride is an important inorganic compound used as a source of zinc and has other numerous industrial applications. Unfortunately, it lacks reliable and accurate physicochemical, thermal, and spectral characterization information altogether. Hence, the authors tried to explore in-depth characterization of zinc chloride using the modern analytical technique. Materials and Methods: The analysis of zinc chloride was performed using powder X-ray diffraction (PXRD), particle size distribution, differential scanning calorimetry (DSC), thermogravimetric analysis/differential thermogravimetric analysis (TGA/DTG), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform-infrared (FT-IR) analytical techniques. Results: The PXRD patterns showed well-defined, narrow, sharp, and the significant peaks. The crystallite size was found in the range of 14.70–55.40 nm and showed average crystallite size of 41.34 nm. The average particle size was found to be of 1.123 (d10), 3.025 (d50), and 6.712 (d90) µm and average surface area of 2.71 m2/g. The span and relative span values were 5.849 µm and 1.93, respectively. The DSC thermogram showed a small endothermic inflation at 308.10°C with the latent heat (∆H) of fusion 28.52 J/g. An exothermic reaction was observed at 449.32°C with the ∆H of decomposition 66.10 J/g. The TGA revealed two steps of the thermal degradation and lost 8.207 and 89.72% of weight in the first and second step of degradation, respectively. Similarly, the DTG analysis disclosed Tmax at 508.21°C. The UV-vis spectrum showed absorbance maxima at 197.60 nm (λmax), and FT-IR spectrum showed a peak at 511/cm might be due to the Zn–Cl stretching. Conclusions: These in-depth, comprehensive data would be very much useful in all stages of nutraceuticals/pharmaceuticals formulation research and development and other industrial applications. Source: https://www.trivedieffect.com/science/a-comprehensive-physicochemical-thermal-and-spectroscopic-characterization-of-zinc-ii-chloride-using-x-ray-diffraction-particle-size-distribution-differential-scanning-calorimetry-thermogravime http://www.jpionline.org/article.asp?issn=2230-973X;year=2017;volume=7;issue=1;spage=33;epage=40;aulast=Trivedi &nbsp

Menthyl acetate has a characteristic, fresh, pungent flavor and a cool mouthfeel. It has been widely used in many products. Because of its high volatility and short shelf-life, menthyl acetate-β-cyclodextrin inclusion complex was produced to provide protection, enhance stability and control release of menthyl acetate. The inclusion complex was characterized by Fourier transform infrared spectroscopy, x-ray diffraction. The results show that menthyl acetate was successfully encapsulated in β-cyclodextrin. Menthyl acetate loading capacity was obtained from the weight loss difference between blank β-cyclodextrin and inclusion complex, and the value is about 8.5 %. Kinetics and release characteristics of menthyl acetate from complex were determined by thermogravimetric analysis. Menthyl acetate release mainly occurred in the first stage before β-CD decomposition. Because menthyl acetate-β-CD inclusion complex is a poor conductor of heat, the methyl acetate release peak shifted towards higher temperature with an increase in heating rate. Menthyl acetate release activation energies were obtained and the average value is 258.7 kJ/mol. Kinetics and release characteristics are basis data for better understanding the mechanism and the combination of host and guest.

This paper presented a mechanism study of syngas production through lipid-extracted microalgal residues by investigating how the structure of these residues affected the pyrolysis characteristics. The results showed that both Chlorella sorokiniana 21 and Monoraphidium 3s35 residues could be pyrolyzed efficiently at low temperatures from 120 to 380 °C, with a final residue of less than 22.75%. Hemicellulose with carboxyl groups was the main component of both microalgal residues, most likely contributing to the production of the C=O compounds and carbon monoxide (CO). A large amount of CHO, CH2O, and CH3O (60.09% in total) was observed from C. sorokiniana 21, which was 1.58 times more than that from Monoraphidium 3s35. Pyrolysis of the C. sorokiniana 21 residue yielded more C=O and CHn compounds with less activation energy (52.97–58.57 kJ mol−1) and a higher reaction rate (0.105% s−1) than that of Monoraphidium 3s35. The different pyrolysis characteristics between the two microalgal residues might be attributed to structural variations.

Nanoparticulate SnO2 produced by a hydrothermal method was characterised by BET, XRD, TGA-MS and in situ variable temperature diffuse reflectance infra red spectroscopy (DRIFTS) to determine the surface behaviour of water. For the (100) facets, hydrogen bonding does not occur, and water adsorption is less strong than for the (111) and (110) facets where hydrogen bonding does occur. Reversible uptake of oxygen was observed. These findings have implications for other surface-gas reactions in which Ni and Sb co-doped SnO2 (NATO) anodes are used for ozone generation. BET showed the relatively high surface area and nanometer scale of the SnO2 particles, whilst XRD confirmed the nano dimension of the crystallites and showed only the cassiterite phase. TGA analysis indicated four temperature regions over which mass loss was observed. These and the in situ DRIFTS studies revealed the existence of various forms of water associated with specific crystal facets of the SnO2, as well as the existence of isolated O-H groups and adsorbed oxygen species. Electronic absorptions were also observed and the data rationalised in terms of the existence of both free electron absorptions, and absorptions from oxygen vacancy states. The role of adsorbed molecular oxygen in electrochemical ozone generation at Ni and Sb co-doped SnO2 (NATO) anodes was strongly suggested by this work.

Flame-retarded poly(1,4-butylene terephthalate) (PBT) has been prepared using aluminum hypophosphite (AHP) and tri(1-oxo-2,6,7-trioxa-1-phosphabicyclo[2,2,2]octane-methyl)phosphate (Trimer). The combustion properties of flame-retarded PBT were evaluated using limiting oxygen index, UL-94, and cone calorimetry. The cone calorimeter data indicated that the presence of PBT/AHP/Trimer imparted a significant smoke-suppressing effect. The thermal degradation properties of flame-retarded PBT were investigated using thermogravimetric analysis–Fourier transform infrared and thermogravimetric analysis–mass spectrometry. For the samples of PBT, PBT/25% AHP, and PBT/AHP/Trimer, the main gas pyrolysis products were CO2 and butadiene; the sample of PBT/AHP/Trimer generated less CO2 and butadiene and consequently retained more carbon in the matrix. The amount of phosphorus–oxygen radicals of PBT/25% AHP was 1.3 times that of PBT/AHP/Trimer, which indicated that AHP alone showed slightly stronger gaseous phase effect tha...

Vermicompost produced from palm oil mill effluent was evaluated for its maturity using: (i) spectroscopic analysis (Fourier transform infrared spectroscopy (FT-IR) and ultraviolet visible (UV–vis) spectroscopy); (ii) structural characterization (scanning electron microscope (SEM) and Brunauer, Emmett and Teller (BET) surface area) and (iii) thermogravimetric (TG) analysis. The FT-IR showed increased mineralization of polysaccharides, carbohydrates and aliphatic methylene compounds in the vermicompost as compared to the control (without earthworms). A slight increase of aromatic compounds was observed and proven by UV–vis spectroscopy analysis for vermicompost. Structural characterization (SEM micrographs) of the vermicompost was revealed to be more fragmented than initial wastes and control. The vermicompost also showed larger surface area by using BET method. Finally, the TG analysis showed lower mass loss in the vermicompost in comparison with the initial wastes and control, suggesting higher stability in feedstock which had undergone vermicomposting process. The first derivative curve from TG analysis also showed degradation of various compounds, which was consistent with the spectroscopic characterization.

Slow pyrolysis of bamboo is an important conversion pathway to produce biofuels and chemicals such as biomass-derived fertilizer precursor (biochar). In this study, evolved gas analysis during pyrolysis of bamboo was conducted by a combination of TG, FTIR and GC–MS to establish a detailed pyrolysis mechanism of bamboo biomass. The main decomposition temperature zones were 300–400 °C and it reached the maximum mass loss intensity at 350 °C based on DTG curves. The main functional groups escaped from biomass during pyrolysis were –OH, –CH2, –CH3, C O, C–O, and –COOH. The main compounds during pyrolysis of bamboo were acetic acid and 2-propenoic acid, ethenyl ester at 300 °C, 2-oxo-propanoic acid and 1-hydroxy-2-propanone at 350 °C and acetic acid and acetic acid ethenyl ester at 400 °C. Evolved gas analysis indicated that components in bamboo occurred in different temperatures and pyrolysis mechanisms and resulted in distinguishing pyrolysis product emission characteristics.

The naturalized dyes (ND) and the traditional acid dyes (ADs) were compared by studying the different behavior during the leather dyeing process. NDs are glyconjugated compounds synthesized by the covalent union of a dye species with a natural sugar (e.g. lactose) able to confer water-soluble properties to the dye molecule as a whole. The interactions between the dyes and the leather proteins were studied by FT-IR spectroscopy and thermogravimetric (TG) analyses. The protein cross-linking of the dyed leather samples was investigated by studying the 1654/1690 cm(-1) peak height ratio and a deconvolution procedure of the amide I peak. The helix secondary structure was the predominant component of the leather proteins of the samples dyed with low concentrations of NDs (2%), while the beta-sheets prevailed when leather samples were dyed with the traditional ADs and high concentrations of NDs (>5%). The data were discussed with respect to TG results. (C) 2015 Elsevier Ltd. All rights reserved.

In this study, the effect of different cooking processes (blanching, roasting and frying) on the oxidative stability of almonds under normal storage and accelerated oxidation conditions were investigated. Fried almonds showed higher initial linoleic acid content due to oil frying medium migration to the samples. As oxidation time increased, a different trend in fatty acid composition was obtained depending on the oxidation conditions used. Samples processed at high temperatures presented an initial high PV, resulting in an advanced state of oxidation. A simultaneous formation of hydroperoxides and secondary oxidation compounds was observed in samples under normal storage, presenting raw samples of the lower PV and AV. Lower values of thermal parameters (DSC and TGA) were obtained with increasing oxidation time at 100°C. The most abundant volatile compounds (HS-SPME-GC-MS) present in raw almonds were benzaldehyde, 1,3-dimethyl-benzene, 1,2-dimethyl-benzene, styrene, 3-methyl-1-butanol, alpha-pinene and limonene; whereas roasted almonds showed Maillard reaction volatiles such as pyrazines, pyrroles and furans; and fried almonds showed compounds derived from frying oil decomposition (trans,cis-2,4-decadienal and trans,trans-2,4-decadienal) and higher amounts of aldehydes (hexanal, octanal and nonanal). The generation of hydroperoxides, their degradation and the formation of secondary oxidation products were also investigated by FTIR analysis. The authors would like to thank Conselleria de Educación (Spain) for ACIF/2010/172 Predoctoral Research Training Grant.

Bio-ferment residues (BR) are wastes produced by a biological fermentation process for the production of antibiotics. In this work, the evolution characteristics of pyrolysis products of BR were studied using TG-FTIR analysis and MS analysis. It was found that species such as H2O, NH3, CH4, carboxylic acid, aldehydes, alkanes, HCN, HNCO, CO, and CO2 were released at a temperature lower than 600°C. Above 600°C, the dominant products were H2, CO, and CO2. Scarcely any acetylene or benzene was observed. HCN and HNCO were found to evolve in a small amount, while other potential pollutants such as H2S, COS, and CS2 were hardly detected.

The flammability of epoxy resin (EP) and its composite with ammonium polyphosphate (EPAPP) was investigated with limiting oxygen index (LOI), UL 94, and cone calorimeter tests. A systematic and comparative evaluation of the thermal degradation of EP and EPAPP has been investigated using thermogravimetry coupled with Fourier transform infrared spectroscopy (TG–FTIR) and thermogravimetry coupled with mass spectrometry (TG–MS). The results showed that the flame retardant of ammonium polyphosphate (APP) can constitute an intumescent flame retardant (IFR) system with EP, and APP can effectively improve the LOI of EP; with 6 wt% addition level of APP, EPAPP can pass UL 94 V 0 test. The cone calorimeter test results showed that the flame retardancy and smoke suppression of EP were significantly improved by APP, and toxic gas products such as carbon monoxide and carbon dioxide obviously decreased. Thermogravimetry–Fourier transform infrared spectroscopy and TG–MS results showed that the degradation process of EP ...

To fill the shortages in the knowledge of the pyrolysis and combustion properties of new and aged polyvinyl chloride (PVC) sheaths, several experiments were performed by thermogravimetric analysis (TG), Fourier transform infrared (FTIR), microscale combustion calorimetry (MCC), and cone calorimetry. The results show that the onset temperature of pyrolysis for an aged sheath shifts to higher temperatures. The value of the main derivative thermogravimetric analysis (DTG) peak of an aged sheath is greater than that of a new one. The mass of the final remaining residue for an aged sheath is also greater than that of a new one. The gas that is released by an aged sheath is later but faster than that of a new one. The results also show that, when compared with a new sheath, the heat release rate (HRR) is lower for an aged one. The total heat release (THR) of aged sheath is reduced by 16.9–18.5% compared to a new one. In addition, the cone calorimetry experiments illustrate that the ignition occurrence of an aged sheath is later than that of a new one under different incident heat fluxes. This work indicates that an aged sheath generally pyrolyzes and it combusts more weakly and incompletely.

In this study, the thermal behavior of polyacenaphthylene (PAcN) and partially modified polyacenaphthylene with Cl, Br, and H2PO3 groups, both under air and nitrogen atmosphere, have been investigated. The influence of the molecular weight, the heating rate, and the introduced substituent have been studied. Thermogravimetric Analysis combined with Fourier Transform Infrared Spectroscopy was used to determine the thermal stabilities and the degradation mechanism. All polyacenaphthylene samples degrade through a depolymerisation process under a nitrogen atmosphere, whereas in air, elimination and thermo-oxidation reactions take place.

This study evaluates the thermal property of clay dispersed Styrene-co-Glycidal Methacrylate impregnated wood polymer nanocomposite (WPNC). The WPNC was characterized by FTIR, TGA and DSC methods. FT-IR result showed that the absorbance of wave number at 1730 cm−1, increased for clay dispersed Styrene-co-Glycidyl Methacrylate wood polymer nanocomposite (ST-co-GMA-clay-WPNC). From TGA, ST-co-GMA-clay-WPNC showed better thermal stability at the temperature below 450oC. The final weights of ST-co-GMA-clay-WPNC and ST-Clay-WPNC, between 420 and 700oC, were significantly less than the raw wood. When the temperature was below 450oC, nanoclay-incorporated surface modified wood composites showed enhanced higher thermal properties compared with those without nanoclay. From DSC, the degradation enthalpy at around 360oC of ST-co-GMA-Clay- WPNC was the highest.

Raman spectroscopy, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy, and transmission electron microscopy are used to assess structural changes generated on the surface of multi-walled (MWCNTs) and single-walled (SWCNTs) carbon nanotubes. Different levels of structural modifications are generated by the use of acidic oxidative treatments. It is found that Raman spectroscopy is a very powerful technique to assess structural modification of SWCNTs with initial low defect concentration. For MWCNTs grown by chemical vapor deposition, which already contain a high density of structural defects in their as-produced state, Raman spectroscopy is not a very sensitive tool to detect the generation of further defects or other structural modifications introduced through acidic treatments. For this later case, TGA is a sensitive technique to assess structural modifications on the nanotubes.

Comparative studies on the Hailar lignite pyrolysis/gasification characteristics at N2/CO2 atmosphere and the influence of inherent mineral matters, external ash and pyrolysis temperature on its reactivity during gasification at CO2 atmosphere were conducted by non-isothermal thermogravimetric analysis, FTIR, and X-ray diffraction (XRD) analysis. Thermogravimetric test results show that the atmosphere of N2 or CO2 almost has no effects on the pyrolysis behavior, and the gasification reaction under CO2 atmosphere occurs over 943 K at the heating rate of 40 K min−1. The external ash prepared at 1173 and 1223 K shows a certain catalytic effect on promoting the gasification reaction, although the inherent mineral matters of Hailar lignite are found in stronger catalytic effects on gasification than the external ash. The lignite gasification reactivity decreases with increasing pyrolytic temperature between 1073 and 1273 K.

The thermal degradation of chitosan–cobalt complex at different heating rates in nitrogen was studied by thermogravimetric analysis (TGA) in the temperature range 30–800 °C. Fourier transform-infrared (FTIR) and X-ray diffractogram (XRD) analyses were utilized to determine the micro-structure of chitosan–cobalt complex. The results indicate that the thermal degradation of chitosan–cobalt complex in nitrogen is a two-step reaction, characteristic temperatures and the maximum reaction rate of thermal degradation increase with the increment of heating rate. The kinetic parameters were determined by using Friedman and Flynn–Wall–Ozawa methods. Coats–Redfern method was used to discuss the probable degradation mechanism. The results show that activation energy of the complex resulting from two kinetic methods has similar variable tendency, and the solid-state decomposition in the first degradation stage, which is non-spontaneous, goes to a mechanism involving nucleation and growth, Avrami–Erofeev function ( A 4 ) with integral form [−ln(1 − α )] 4 .

In this research, thermogravimetric analysis (TGA) was used to investigate the structural changes that occur during cotton fiber development starting at 10 days post-anthesis (dpa). The percent weight losses attributed to water, non-cellulosic materials, and cellulose macromolecules were calculated from the thermograms. Valuable information was obtained related to the composition of the cell wall and the timing of the transition between the primary cell wall and the secondary cell wall. The results indicated that the two cultivars investigated (TX19 and TX55) exhibited different structural evolution. The transition phase between the primary cell wall and the secondary cell wall occurs between 17 and 18 dpa in fibers from the TX19 cultivar, while this transition occurs between 21 and 24 dpa for fibers from the TX55 cultivar. These conclusions are in agreement with the results obtained with Fourier transform infrared spectroscopy.

The present study was conducted to investigate the physicochemical properties and pyrolysis kinetics of sugarcane bagasse (SB). The physiochemical properties of SB were determined to examine its potential for pyrolysis. The physiochemical properties such as proximate analysis, ultimate analysis, heating values, lignocellulosic composition, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) of SB were investigated. The pyrolysis experiments were conducted in a nonisothermal thermogravimetric analyzer (TGA) to understand the thermal degradation behavior of SB. The activation energy (Ea) of SB pyrolysis was calculated by model-free Kissinger–Akahira–Sunose (KAS) and Ozawa–Flynn–Wall (OFW) methods. Average values of activation energy determined through KAS and OFW methods are found as 91.64 kJ/mol and 104.43 kJ/mol, respectively. Variation in the activation energy with degree of conversion was observed, which shows that pyrolysis is a complex process composed of several reactions. Coats–Redfern method was used to calculate the pre-exponential factor and reaction order. Conversion of SB due to heat treatment computed by using the kinetic parameters is found to be in good agreement with the experimental conversion data, and the maximum error limit between the experimental and predicted conversions is 8.5% for 5 °C/min, 6.0% for 10 °C/min, and 11.6% for 20 °C/min. The current investigation proves the suitability of SB as a potential feedstock for pyrolysis.

In this study, the relationship between wood cellulose crystallinity, influence of extractives on wood degradation, correlation between chemical composi- tion, and physical properties of four wood species were investigated by chemical analysis, Fourier transform infra- red (FTIR) spectroscopy, and thermogravimetry. The chemical analysis showed that Dipteryx odorata and Mezi- laurus itauba (ITA) contained a higher quantity of extrac- tives and lower quantities of holocellulose and lignin than Eucalyptus grandis (EUG) and Pinus elliottii. FTIR spectros- copy indicated that higher extractives content in ITA might be associated with more intense bands at 2920, 2850, and 1510 cm � 1 . The lower values for hydrogen bond energy and hydrogen bond intensity showed that EUG contained more absorbed water than the other species. Thermogravimetry confirm that lower extractive contents leads to a better wood thermal stability. This study showed that through the methods used previous informa- tion about structure and properties of wood can be obtained before use it in composite formulations. V C 2012

Maturity of kerogen in shale governs the productivity of a shale formation. Produced fluids are strongly dependent upon organic type (governed by depositional fossils and environment) and thermal history. Different maturity measurement methods (vitrinite reflectance, Rock Evaluation, biomarkers) have been studied, but failed to precisely determine maturity levacross all levels of maturity. Vitrinite reflectance (%Ro) measurement cannot be applied for marine shales and pre-Silurian shales, which do not include plant materials. Tmax (main maturity indicator from Rock Evaluation pyrolysis) measurement is questionable for mature and post-mature samples. Most of biomarkers become useless when maturity level reaches condensate window. In this study, we introduce using Fourier Transmission Infrared Spectroscopy (FTIR) and Thermogravimetric (TGA) for both qualitative and quantitative assessment on organic maturity in shale. Separation of organic matter or identification macerals is not required by either technique; they are quick and objective tests providing two IR-based maturity indices. The first index, CH2/CH3, (from FTIR alone) shows good sensitivity up to the end of the condensate window. CH2/CH3 index decreases with more mature samples. The following CH2/CH3 values are used to define the immature (>1.63 ± 0.22), oil window (1.63 ± 0.22 to 1.3 ± 0.25), wet gas window (1.3 ± 0.25 to 1.13±0.05), and dry gas window (

We report the covalent functionalization of single-walled carbon nanotubes (SWNTs) with biotin. The synthesized functionalized SWNT materials were fully characterized by FTIR and thermogravimetric analysis. These characterization techniques provided valuable information concerning the nature of the obtained SWNT materials as well as the efficiency of the employed synthetic route towards SWNT covalent functionalization with biotin.