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investigated by thermogravimetric analysis. The carbonisation temperatures were determined from thermogravimetry (TG) results. The effect of carbonisation temperatures on nanoporous characteristics of ACF was then studied. Experimental

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multicellular thermally stable char insulating the underlying material from the flame action [ 8 ]. A typical intumescent system comprises an acid source—a dehydration catalyst for char formation, a carbon source—a carbonization agent (carbon-rich compounds) and

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937 943 Morvová, M., Morva, I., Janda, M., Hanic, F., Lukáč, P. (2003): Combustion and carbonisation exhaust utilisation in electric discharge and its relation to prebiotic

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Abstract  

The development of innovative clean-up technologies remains a challenge as current procedures have many limitations, such as being expensive, concentration or pollutant specific, and many others. Natural zeolite of clinoptilolite type was beneficiated with surfactant octadecylammonium and alginate biopolymers using the sol-gel method. Carbonization process in pyrolysis chamber combusted organic waste materials and reaching the maximum temperature of 700°C was used for the surface carbonization, respectively. Resulted zeolite based products were analyzed by FTIR, TG, DTA and examined on the selected aqueous pollutants removal using the conventional laboratory adsorption experiments. The ability of ODA and alginate linked zeolite of clinoptilolite type to form complexes with anions (such as nitrate, sulphate, chloride and phosphate) and to remove them from contaminated waters was validated. Carbon deposition onto clinoptilolite surface originated from the pyrolytic carbon-rich waste combustion simulated the new zeolite based hybrid to active coke, adsorption efficiency of which towards phenol was approved. Thermogravimetric analyses of the advanced zeolite-based adsorbents were accomplished to find out how temperature resistant are the novel zeolite based materials in respect to the original, untreated one. While the native clinoptilolite indicated according to DTA analysis one broad endothermic response around 100–130°C, resulted from the loss of adsorbed water, by the ODA-modified clinoptilolite was except this DTA peak, the broad exothermic response started from 370 up to 560°C observed. This DTA profile is assumed to record a slowly breakdown of attached ODA surfactant and sequential loss of mass due to continual heating of sample under elevated temperature.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: R. Selvakumar, S. Aravindh, C. Kaushik, V. Katarani, Vidya Thorat, Prema Gireesan, V. Jayavignesh, K. Swaminathan, and Kanwar Raj

Abstract  

The present study involves the screening of silver nanoparticles containing carbonized yeast cells isolated from coconut cell sap for efficient adsorption of few long lived radionuclides like 137Cs55, 60Co27, 106Ru44, 239Pu94 and 241Am95. Yeast cells containing silver nanoparticles produced through biological reduction were subjected to carbonization (400 °C for 1 h) at atmospheric conditions and their properties were analyzed using fourier transform infra-red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscope. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells without silver exposure (CCY) did not contain any particles on its surface. The efficiency of CSY and CCY towards the radionuclide adsorption was studied in batch mode at fixed contact time, concentration, and at its native pH. CSY was efficient in removal of 239Pu94 (76.75%) and 106Ru44 (54.73%) whereas CCY showed efficient removal only for 241Am95 (62.89%). Both the adsorbents did not show any retention with respect to 60Co27 and 137Cs55. Based on the experimental data, decontamination factor and distribution coefficient (K d) were calculated and, from the values, it was observed that these adsorbents have greater potential to adsorb radionuclides.

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Abstract  

The industrial porous co-polymers and resins in the form of spherical granules include three main matrices which serve as the basis of the large-scale production of ion-exchange materials: styrene/divinylbenzene, vinylpyridine/divinylbenzene and acrylonitrile/divinylbenzene. Complex thermal methods (TG, DTG and DTA) were used to study the carbonization processes of various industrial products utilized as starting materials for the preparation of synthetic active carbons. The DTG results, the thermal effects observed during the programmed heating of samples, and the mass-spectrometric and IR-spectroscopic data up to 800C provided a picture of a multi-stage carbonization process. This includes the removal of moisture from the polymer matrices, the primary cross-linking of the chains, their aromatization and condensation due to the cross-linking of polynuclear structures, and the removal of ‘excess carbon’ as simple molecules and free radicals of hydrocarbon type. The results promoted the choice of the optimal regimes in which to carryout the isothermal pyrolysis of various polymer matrices and preliminary chemical modifications to increase the yields on carbon and to prepare synthetic active carbons such as those of SCN, SCAN and SCS types. General schemes were proposed for the chemical reactions accompanying the carbonization process for these polymer matrices.

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Plain and N-doped carbonaceous particles are synthesized from biomass resources such as glucose via continuous hydrothermal carbonization (HTC) process at 200 °C and 250 psi for the first time using a microfluidic system in a fast and continuous manner. The continuous HTC is controlled by reaction time (3.7–30 min) and concentration (0–10 wt.%) of ethylenediamine as a nitrogen additive to produce a series of the plain carbonaceous and N-doped carbonaceous particles with size range from 0.8 to 1.2 um. The as-synthesized and the pyrolyzed particles are characterized by various analytical instruments to understand their chemical structures with elemental compositions, morphology of particles, and thermal defunctionalization.

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Abstract  

Apricot stone shells were carbonized under certain chemical and thermal conditions to produce sorbents having a quantitative affinity to retain some radioactive nuclei. The sorbent shows a thermal stability upto 500 °C. The diffraction patterns clarify that the sorbent is mainly amorphous in structure. Carbon in these shells was elementally analyzed and the data reveal a predominant content of acidic surface centers with hydrophilic properties. The isoelectric point (pHPZC) was determined and found to be 4.2 implying the acidic nature of the sorbent surface. The sorption of Cs+, Co2+ and Eu3+ on the prepared sorbent was studied from aqueous solution under different variables and the sorption capacity had values from 0.23-1.15 meq/g.

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Journal of Thermal Analysis and Calorimetry
Authors: A. Gribanov, L. Shibaev, A. Koltsov, R. Teeiaer, Yu. Sazanov, N. Stepanov, E. Lippmaa, and T. Székely
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Abstract  

Whole grains of emmer wheat were heated in a pre-heated tube oven at temperatures ranging from 130-700C under controlled anoxic conditions for maximum 280 min. For each temperature a separate experiment was carried out. Physical properties including mass loss, thermal lag, external and internal morphology and the vitrinite reflectance, C and N content, and DTMS under CI (NH3) and EI conditions were used to monitor changes as a function of the temperature. The results show remaining starch and protein rich material up to 250C. From 310-400C a secondary, thermally stable, product is formed and at higher temperatures a strongly carbon enriched tertiary product.

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