Thermogravimetric analysis

About: Thermogravimetric analysis is a research topic. Over the lifetime, 37248 publications have been published within this topic receiving 862144 citations. The topic is also known as: thermal gravimetric analysis & TGA.

Chitosan-functionalized graphene oxide: A novel adsorbent an efficient adsorption of arsenic from aqueous solution

Abstract: Nowadays, there is a wide variety of arsenic decontamination processes being adsorption processes the most efficient. In this concern, chitosan functionalized graphene oxide (GO), have been proposed as an efficient adsorbent to improve arsenic adsorption from aqueous solutions. The chitosan functionalized GO adsorbent acts as a good host of welcoming the incoming guest, arsenic oxyanion and several interesting interactions such as cation–π interaction, (RNH 3 + ---aromatic π moiety), electrostatic interaction (H 2 AsO 4 − , HAsO 4 2− ---- + NH 3 R), inter and intermolecular hydrogen bonding as well as anion–π interaction (R-COO − ---aromatic π moiety), (R–O − ---aromatic π moiety), could be conceptualized in this process, the abundant oxygen-containing functional groups on the adsorbent surfaces play an important role on As(V)/As(III) adsorption. The prepared chitosan-GO adsorbent was characterized by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, thermogravimetric analysis (TGA) analysis, powder-X-ray diffraction (powder-XRD), transmission electron microscopes (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopes (SEM) and energy dispersive X-ray analysis (EDX) studies. The capability of ICP-MS for As(III)/As(V) adsorption was extensively studied under different optimal parameters in aqueous solutions, the applicability of this method is demonstrated economical and practical applications for efficient adsorption of arsenic from aqueous solutions.

Thermal stability of lithium nickel oxide derivatives. Part I: LixNi1.02O2 and LixNi0.89Al0.16O2 (x = 0.50 and 0.30)

Abstract: The thermal degradation mechanism of LixNi1.02O2 and LixNi0.89Al0.16O2 (x = 0.50 and 0.30) was studied by in situ X-ray diffraction correlated with thermal gravimetric analysis coupled with mass spectrometry. The degradation mechanism appears to be the same for both types of samples. It consists of two steps: the first step, corresponding to the lamellar to pseudo-spinel transformation, is accompanied by an oxygen loss only for compounds with an initial (Li + M)/O ratio (M = Ni, Al) smaller than 3/4. The second step corresponds to the progressive transformation to a NiO-type structure, with an oxygen loss for both initial lithium compositions. The thermal stabilization obtained by partial aluminum substitution for nickel can be explained by the stability of the Al3+ ions in tetrahedral sites, which disrupts the cationic migrations necessary for the phase transformations observed upon increasing temperature to occur.

Efficient planar perovskite solar cells based on 1.8 eV band gap CH3NH3PbI2Br nanosheets via thermal decomposition.

Abstract: Hybrid organometallic halide perovskite CH3NH3PbI2Br (or MAPbI2Br) nanosheets with a 1.8 eV band gap were prepared via a thermal decomposition process from a precursor containing PbI2, MABr, and MACl. The planar solar cell based on the compact layer of MAPbI2Br nanosheets exhibited 10% efficiency and a single-wavelength conversion efficiency of up to 86%. The crystal phase, optical absorption, film morphology, and thermogravimetric analysis studies indicate that the thermal decomposition process strongly depends on the composition of precursors. We find that MACl functions as a glue or soft template to control the initial formation of a solid solution with the main MAPbI2Br precursor components (i.e., PbI2 and MABr). The subsequent thermal decomposition process controls the morphology/surface coverage of perovskite films on the planar substrate and strongly affects the device characteristics.

Thermal decomposition of carboxylate ionic liquids: trends and mechanisms

Abstract: The thermal stability of a series of dialkylimidazolium carboxylate ionic liquids has been investigated using a broad range of experimental and computational techniques. Ionic liquids incorporating fluoroalkyl carboxylate anions were found to have profoundly differing thermal stabilities and decomposition mechanisms compared with their non-fluorinated analogues. 1-Ethyl-3-methylimidazolium acetate was observed to largely decompose via an SN2 nucleophilic substitution reaction when under inert gas conditions, predominantly at the imidazolium methyl substituent. The Arrhenius equations for thermal decomposition of 1-ethyl-3-methylimidazolium acetate, and the C2-methylated analogue 1-ethyl-2,3-dimethylimidazolium acetate, were determined from isothermal Thermogravimetric Analysis experiments. The low thermal stability of 1-ethyl-3-methylimidazolium acetate has important implications for biomass experiments employing this ionic liquid. For these two ionic liquids, ion pair and transition state structures were optimised using Density Functional Theory. The activation barriers for the SN2 nucleophilic substitution mechanisms are in good agreement with the experimentally determined values.

Preparation of copper nanoparticles coated cellulose films with antibacterial properties through one-step reduction.

Abstract: Regenerated cellulose (RC) films coated with copper (Cu) nanoparticles were prepared from cellulose-cuprammonium solution through coagulation in aq. NaOH and subsequent reduction in aq. NaBH4. Structure and morphology of the nanocomposite films were characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The results established the migration of Cu(2+) from the inner to the surface of the RC films during the coagulation of cellulose-cuprammonium solution and the reduction from Cu(2+) to Cu(0). Cu nanoparticles were found to be firmly embedded on the surface of the RC films. The RC films coated with Cu nanoparticles showed efficient antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The dramatic reduction of viable bacteria could be observed within 0.5 h of exposure, and all of the bacteria were killed within 1 h.