Chemical and Energetic Characterization of the Wood of Prosopis laevigata: Chemical and Thermogravimetric Methods.

Diverse methodologies exist to determine the chemical composition, proximate analysis, and calorific value of biomass. Researchers select and apply a specific methodology according to the lignocellulosic material they study and the budgetary resources available. In this project, we determined the primary chemical constitution and proximate analysis of Prosopis laevigata (Humb. & Bonpl.) Jonhst wood using a traditional chemical method and a novel procedure based on the deconvolution of the DTG signal produced by TGA. The highest calorific value was verified using a calorimetric pump based on mathematical models. We also conducted elemental analysis and a microanalysis of ash, and applied Fourier transform infrared spectroscopic analysis (FT-IR). The means of the results obtained by the chemical method and TGA-DTG, respectively, were: hemicelluloses 7.36%-(8.72%), cellulose 48.28%-(46.08%), lignin 30.57%-(32.44%), extractables 13.53%-(12.72%), moisture 2.03%-(4.96%), ash 1.77%-(1.90%), volatile matter 75.16%-(74.14%), and fixed carbon 23.05%-(18.93%). The procedure with the calorimetric pump generated a calorific value above 20.16 MJ/kg. The range generated by the various models was 18.23-21.07 MJ/kg. The results of the elemental analysis were: carbon 46.4%, hydrogen 6.79%, oxygen 46.43%, nitrogen 0.3%, and sulfur 0.5%. The microanalysis of ash identified 18 elements. The most abundant ones were potassium ˃ calcium ˃ sodium. Based on the infrared spectrum (FT-IR) of Prosopis laevigata wood, we detected the following functional groups: OH, C-H, C=O, CH2, CH3, C-O-C, C-OH, and C4-OH. Our conclusion is that the TGA-DTG method made it possible to obtain results in less time with no need for the numerous reagents that chemical procedures require. The calorific value of P. laevigata wood is higher than the standards. Finally, according to our results, proximate analysis provides the best model for calculating calorific value.

Pyrolysis and Physicochemical, Thermokinetic and Thermodynamic Analyses of Ceiba aesculifolia (Kunth) Britt and Baker Waste to Evaluate Its Bioenergy Potential.

Ceiba aesculifolia is an important species in Mexico that generates significant amounts of biomass waste during its exploitation, which can be utilized to produce energy. This study presents the characterization of this waste based on chemical (proximal and elemental) and thermal analyses (TGA-DTG) at different heating rates (ß = 10-30 °C/min (283-303 K/min)) in the presence of nitrogen and in a temperature range of 25-900 °C. Kinetic parameters were calculated and analyzed as well. Activation energy (Ea) and the pre-exponential factor (A) were determined using the Friedman (132.03 kJ/mol, 8.11E + 10 s -1), FWO (121.65 kJ/mol, 4.30E + 09), KAS (118.14 kJ/mol, 2.41E + 09), and Kissinger (155.85 kJ/mol, 3.47E + 11) kinetic methods. Variation in the reaction order, n (0.3937-0.6141), was obtained by Avrami's theory. We also calculated the thermodynamic parameters (ΔH, ΔG, ΔS) for each kinetic method applied. The results for Ea, A, n, ΔH, ΔG, and ΔS show that this biomass waste is apt for use in pyrolysis. Moreover, the moisture (<10%), ash (<2%), volatile material (>80%), and HHV (>19%) contents of C. aesculifolia allowed us to predict acceptable performance in generating energy and fuels. Finally, infrared spectroscopy analysis (FT-IR) allowed us to identify important functional groups, including one that belongs to the family of the aliphatic hydrocarbons.

Synthesis, Thermogravimetric Analysis, and Kinetic Study of Poly-N-Isopropylacrylamide with Varied Initiator Content.

The thermal decomposition and kinetic parameters of four polymers, PN-1, PN-05, PN-01, and PN-005, were determined by thermogravimetry (TGA/DTG) under non-isothermal conditions. N-isopropylacrylamide (NIPA)-based polymers were synthesized by the surfactant-free precipitation polymerization (SFPP) with different concentrations of the anionic initiator potassium persulphate (KPS). Thermogravimetric experiments were carried out in the temperature range of 25-700 °C at four heating rates, 5, 10, 15, and 20 °C min-1, under a nitrogen atmosphere. Poly NIPA (PNIPA) showed three stages of mass loss during the degradation process. The thermal stability of the test material was determined. Activation energy values were estimated using Ozawa, Kissinger, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Friedman (FD) methods.

Evaluating the role of feldspar on the resistivity of alkali-activated slag towards seawater attack.

In this study, the effect of K-feldspar on the behavior of alkali-activated slag pastes (AAS) before and after exposure to seawater was evaluated by measuring the compressive strength and the microstructure. To achieve this objective, the mixtures were prepared upon partial replacement of ground granulated-blast furnace slag (GGBFS) with calcined and un-calcined feldspar fine particles (termed as FS and CFS) at levels ranging from 5 to 20%, by mass. Under processing conditions, the solidified specimens were immersed for 1, 7, 14, and 28 days in 100% RH at 40 ± 2 °C. After 28 days, a group of samples having the same composition were soaked in seawater solution for 1, 3, and 6 months. The new phases were evaluated using X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTG), and scanning electron microscopy (SEM). The inclusion of FS and/or CFS in AAS enhances the performance of the pastes in normal and harsh conditions in relation to their reference counterparts. Among all the mixtures that were tested, alkali-activated composite comprising 15% CFS indicated more durable properties in terms of increased compressive strength and dense morphological structure after exposure to an aggressive environment.

Environmental assessment, microstructural behaviour, stress-strain characteristics, and effect of exposure to extreme temperature on sustainable concrete made with dolomite mining residues.

Mining and extraction of stones and minerals play a significant role in many countries economic growth in the world. The production of dolomite minerals in various industries in India and other countries produces vast amounts of waste in different fractions. Disposal of these types of industrial wastes in an immense quantity causes environmental pollution. The performance of dolomite mining residues on concrete properties as a fine aggregate substitute was examined. The microstructural analysis was conducted on the concrete samples to find the effect of dolomite mining residues in concrete. The stress-strain behaviour of the dolomite mining residues concrete was studied. The effect of exposure to elevated temperature and freeze-thaw on concrete properties containing dolomite mining residues was found up to 100% at 10% incremental order. The thermogravimetric analysis (TGA) and differential thermogravimetry (DTG) tests were conducted on the dolomite mining residues and concrete samples. As a test result, concrete properties influence with the incorporation of the dolomite mining residues as a substitution of river sand, but no significant effect is observed in the concrete properties containing 10% dolomite mining residues. Up to 10% of dolomite production waste can be used as a sand substitute in concrete and other applications for sustainable development.

Properties of the PVA-VAVTD KOH Blend as a Gel Polymer Electrolyte for Zinc Batteries.

Rechargeable zinc-air batteries are promising for energy storage and portable electronic applications because of their good safety, high energy density, material abundance, low cost, and environmental friendliness. A series of alkaline gel polymer electrolytes formed from polyvinyl alcohol (PVA) and different amounts of terpolymer composed of butyl acrylate, vinyl acetate, and vinyl neodecanoate (VAVTD) was synthesized applying a solution casting technique. The thin films were doped with KOH 12M, providing a higher amount of water and free ions inside the electrolyte matrix. The inclusion of VAVTD together with the PVA polymer improved several of the electrical properties of the PVA-based gel polymer electrolytes (GPEs). X-ray diffraction (XRD), thermogravimetric analysis (TGA), and attenuated total reflectance- Fourier-transform infrared spectroscopy (ATR-FTIR) tests, confirming that PVA chains rearrange depending on the VAVTD content and improving the amorphous region. The most conducting electrolyte film was the test specimen 1:4 (PVA-VAVTD) soaked in KOH solution, reaching a conductivity of 0.019 S/cm at room temperature. The temperature dependence of the conductivity agrees with the Arrhenius equation and activation energy of ~0.077 eV resulted, depending on the electrolyte composition. In addition, the cyclic voltammetry study showed a current intensity increase at higher VAVTD content, reaching values of 310 mA. Finally, these gel polymer electrolytes were tested in Zn-air batteries, obtaining capacities of 165 mAh and 195 mAh for PVA-T4 and PVA-T5 sunk in KOH, respectively, at a discharge current of -5 mA.

Impact of enrichment with egg constituents on water status in gluten-free rice pasta - nuclear magnetic resonance and thermogravimetric approach.

Effects of freeze-dried egg white, yolk and whole egg enrichment on water behaviour in fresh pasta dough, dried and cooked rice pasta with respect to control samples were studied by 1H nuclear magnetic resonance (NMR) relaxometry and thermogravimetric analysis. Enrichments caused lower mobility of water (T2) localised within the starch-protein matrix in fresh dough as well as dried pasta. Water compartmentalization was also downgraded in cooked products. Water fractions with different T2 values were linked to temperature peaks at the first derivative of the thermogravimetric (DTG) curve. From the DTG curve strong interaction of water molecules with proteins of egg white was revealed. Egg proteins also influenced viscoelastic properties of dough, and enhanced the firmness and chewiness of cooked pasta. Structural changes induced by various types of enrichment were reflected in the different molecular mobility at the water-matrix interface (T1). The enrichments also altered the colour and cooking properties.

Data on FTIR, TGA - DTG, DSC of invasive pennisetum purpureum grass.

The aim of this research is to characterize the invasive grass, Pennisetum purpureum, to evaluate the potentiality of the bioenergy production. Fourier transform infrared (FTIR) spectra are measured in order to understand the functional groups and their structure in the biomass. The thermogravimetric analysis (TGA) and the derivative thermogravimetric analysis (DTG) data are provided under Pyrolysis (N2) and combustion (O2) conditions to reveal the degradation pattern of the biomass. Differential scanning calorimetry (DSC) is the thermochemical process to measure the enthalpy changes pattern of the biomass. The original data presented in this work can be found in a research paper titled "Evaluation of the bioenergy potential of invasive Pennisetum purpureum through pyrolysis and thermogravimetric analysis", by Md Sumon Reza, Shafi Noor Islam, Shammya Afroze, Muhammad S. Abu Bakar, Rahayu S. Sukri, Saidur Rahman, and Abul K. Azad [1].

Analysis of thermal degradation of banana (Musa balbisiana) trunk biomass waste using iso-conversional models.

The thermo-chemical characterization (proximate and ultimate analyses and higher heating value) of banana trunk biomass waste has been carried out. The thermo-gravimetric and differential scanning calorimetric (DSC) investigations have been made at heating rates of 10, 15, 20 and 25 °C/min. The TGA data have been used to carry out kinetic analysis and evaluate the kinetic and thermodynamic parameters using iso-conversional models. The values of activation energy increase with conversion (α) irrespective of the iso-conversional model used. The average values of activation energies (Eα) are found to be 386.21, 355.43, 385.77, 355.01, 379.67, and 292.78 kJ/mol for Flynn-Wall-Ozawa (FWO), Starink, Kissinger-Akahira-Sunose (KAS), Tang, Vyzovkin and Vyzovkin AIC model, respectively. The average values of change in enthalpy, Gibbs free energy, and entropy have been calculated. The reaction mechanisms of pyrolysis have been predicted using Criado's method.

Permeable Nanomontmorillonite and Fibre Reinforced Cementitious Binders.

Clinker reduction in cementitious binders is of paramount importance today, and nanotechnology has extended permissible limits. In the present study, a reference binder consisting of 60% Portland cement, 20% limestone, 20% fly ash, 3% polyvinyl alcohol (PVA) fibres and 2% superplasticizer is optimized with three different types of nano-montmorillonite (nMt) dispersions; two organomodified ones and an inorganic one at different proportions (0.5% to 4%). Flexural strength, measured on day 7, 28, 56 and 90, was improved after day 28 with the addition of inorganic nMt. Thermal gravimetric analyses carried out on day 7, 28, 56 and 90 coupled with x-ray diffraction (at day 28) showed a distinctively enhanced pozzolanic reaction. Backscattered electron imaging confirmed changes in the microstructure. Late age relative density measurements of the nMt cementitious nanocomposites showed higher values than these of the reference paste, which can be attributed to better particle packing. Mercury intrusion porosimetry measurements give support to the optimal nMt dosage, being 1% by total mass of binder and water impermeability tests (modified with BS EN 492:2012) suggest that inorganic nMt can be a viable option material where permeability constitutes a prerequisite. Suggestions for further activation of the nMt-fibre reinforced cementitious nanocomposites were also made.

Characterization of untreated and alkali treated new cellulosic fiber from an Areca palm leaf stalk as potential reinforcement in polymer composites.

The research article addresses, a new natural fibers namely Areca Palm Leaf Stalk Fibers (APLSF) were extracted from an Areca palm tree (Dypsis lutescens) and subjected to various concentrations of alkali treatment (NaOH) such as 5%, 10% and 15% by weight. The effects of this treatment on various properties of the fibers such as physical, chemical and mechanical properties were studied. However, the density of the fibers increased and diameter of the fibers reduced. The chemical result showed that the cellulose content was increased while hemicellulose, lignin, wax and ash contents were reduced. The chemical functional groups present in the fibers were confirmed by FTIR. The 5% alkali treated APLSF exhibited a highest tensile strength of 486.41 ±â€¯35.57 MPa, tensile modulus of 9.89 ±â€¯1.46 GPa and elongation at break of 4.91 ±â€¯1.82%. The surface morphology, surface roughness and thermal stability of fibers were examined by SEM, AFM and TGA/DTG.

Effect of TEMPO-oxidization and rapid cooling on thermo-structural properties of nanocellulose.

Recently, surface functionality and thermal property of the green nanomaterials have received wide attention in numerous applications. In this study, microcrystalline cellulose (MCC) was used to prepare the nanocrystalline celluloses (NCCs) using acid hydrolysis method. The NCCs was treated with TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl)oxy radical]-oxidation to prepare TEMPO-oxidized NCCs. Cellulose nanofibrils (CNFs) also prepared from MCC using TEMPO-oxidation. The effects of rapid cooling and chemical treatments on the thermo-structural property studies of the prepared nanocelluloses were investigated through FTIR, thermogravimetric analysis-derivative thermogravimetric (TGA-DTG), and XRD. A posteriori knowledge of the FTIR and TGA-DTG analysis revealed that the rapid cooling treatment enhanced the hydrogen bond energy and thermal stability of the TEMPO-oxidized NCC compared to other nanocelluloses. XRD analysis exhibits the effect of rapid cooling on pseudo 2I helical conformation. This was the first investigation performed on the effect of rapid cooling on structural properties of the nanocellulose.

Thermal stability and decompositions kinetics under non-isothermal conditions of imatinib mesylate α form.

The thermal decomposition and kinetic parameters of synthetized imatinib mesylate α form α form were determined by thermogravimetry (TGA/DTG) under non-isothermal conditions. The experiments were performed at a 25-940°C temperature range at five different heating rates: 2.5Kmin(-1), 5Kmin(-1), 10Kmin(-1), 15Kmin(-1) and 20Kmin(-1) per minute in a nitrogen atmosphere. Imatinib mesylate α form presents one-step mass loss during the degradation process. The thermal stability of the examined material, the melting temperature (Tonset=220.6°C) and ΔH fusion=-95.74Jg(-1) at a heating rate of 10°Cmin(-1) was established. The values of activation energies have been estimated using Kissinger, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods.

Thermal stability of cellulose and their nanoparticles: effect of incremental increases in carboxyl and aldehyde groups.

Oxidized cellulose containing carboxyl and aldehyde functional groups represent an important class of cellulose derivatives. In this study effect of incrementally increasing COOH and CHO groups at C2, C3, and C6 positions of cellulose and nanocellulose has been investigated, with a view to understanding their effect on thermal treatment of cellulose. The results show that 2,3-dialdehyde cellulose (DAC) is the most thermally stable oxidized product of cellulose while the most unstable derivatives contain carboxyl group at the C6 position (6CC). Carboxymethylcellulose (CMC), with carboxymethyl group on C6 position, is more stable than 6CC. Multi-functionalized celluloses 2,3,6-tricarboxycellulose and 6-carboxy-2,3-dialdehyde, have the same level of thermal stability as 6CC, showing that the presence of carboxyl at the C6 is a key destabilizing factor in the thermal stability of oxidized cellulose products. More the number of reducing end groups on the polymer chain, lower the thermal stability of the cellulose, as proved by comparing the TGA/DTG of monomeric analogs dextrose, cellobiose and glucuronic acid with the oxidized celluloses. The thermal stability trend observed for oxidized celluloses was DAC>DCC>nanoparticles>dextrose>glucuronic acid, caused by extent of reducing ends and COOH groups.