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Abstract  

Char and tar derived from pyrolysis of Uruguayan Eucalyptus wood has been evaluated as raw materials for the preparation of high mechanical resistance activated carbon pellets. Thermogravimetric analysis was used as the main technique for studying tar and char pyrolysis in N2 and CO2 atmospheres, and to determine the best conditions for CO2 activation of the carbon pellets. Results indicated that activated carbon pellets with high surface area and good mechanical resistance were obtained by CO2 gasification at 1098 K. Pellets properties can be explained as due to the independent contribution of each component.

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Summary The influence of the atmospheric conditions such as the oxygen concentration and its pressure on the spontaneous ignition behaviour of activated carbon was investigated with high pressure DSC (HP-DSC), TG-DTA and SIT (spontaneous ignition test). The onset temperature with HP-DSC lowered with the increase of the oxygen concentration and the onset temperature could be predicted with the oxygen concentration. From the adiabatic self-heating profiles observed by SIT the onset temperature lowered with the increase of the oxygen concentration and the activation energy of induction period of exothermic reaction was determined as 28~39 kJ mol-1.

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Abstract

The thermal decomposition of SEX in a nitrogen atmosphere was studied by coupled thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR), and by pyrolysis-gas chromatography-mass spectrometry (py-GC-MS). The TG curve exhibited two discrete mass losses of 45.8% and 17.8% respectively, at 200 and 257–364°C. The evolved gases identified as a result of the first mass loss were carbonyl sulfide (COS), ethanol (C2H5OH), ethanethiol (C2H5SH), carbon disulfide (CS2), diethyl sulfide ((C2H5)2S), diethyl carbonate ((C2H5O)2CO), diethyl disulfide ((C2H5)2S2), and carbonothioic acid, O, S, diethyl ester ((C2H5S)(C2H5O)CO). The gases identified as a result of the second mass loss were carbonyl sulfide, ethanethiol, and carbon disulfide. Hydrogen sulfide was detected in both mass losses by py-GC-MS, but not detected by FTIR. The solid residue was sodium hydrogen sulfide (NaSH).

SEX was adsorbed onto activated carbon, and heated in nitrogen. Two discrete mass losses were still observed, but in the temperature ranges 100–186°C (7.8%) and 186–279°C (11.8%). Carbonyl sulfide and carbon disulfide were now the dominant gases evolved in each of the mass losses, and the other gaseous products were relatively minor. It was demonstrated that water adsorbed on the carbon hydrolysed the xanthate to cause the first mass loss, and any unhydrolysed material decomposed to give the second mass loss.

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Abstract  

The effects of heating temperature of pyrolysis and activation processes on the textural and chemical properties of the chars and activated carbons prepared from oil palm stones, an abundant palm-oil mill solid waste, were studied. For both pyrolysis and activation, relatively high temperature was essential to develop pore structures in the chars and activated carbons. However, too high temperature would cause pore narrowing and pore enlargement during pyrolysis and activation, respectively. The temperature had an insignificant effect on the inorganic components of the chars and activated carbons, but affected their surface organic functional groups significantly.

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Abstract  

The thermochemical decomposition of agricultural by-product corn cob impregnated with ZnCl2, as a precursor material for producing the activated carbons, was investigated by thermogravimetric (TG) analysis at the heating rate of 5 and 10°C min–1 under a controlled atmosphere of nitrogen (60 ml min–1). The appearance of a peak in the differential thermogravimetric plot (DTG) in the temperature range of 400–600°C is significantly related to the extent of impregnation. The DTG curve of the sample impregnated with the optimal impregnation ratio of 175% (i.e., the ratio of ZnCl2 mass of 87.5 g in the 200 cm3 of water to corn cobmass of 50 g), which yields an optimal BET surface area of the activated carbon and displays a DTG peak at about 500°C. This may be partially due to the intense chemical activation and results in the formation of a porous structure in the activated solid residue. This observation is also in close agreement with previous results at optimal pyrolysis temperatures of 500°C and with similar experimental conditions. In order to support the results in the TG-DTG analysis, the development of pore structure of the resulting activated carbons thus obtained by previous studies was also examined and explained using the scanning electron microscopy (SEM).

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Acta Chromatographica
Authors: Liyi Li, Liming Hu, Bingbao Chen, Yanwen Dong, Zixia Lin, Zhiyi Wang, Congcong Wen, Xianqin Wang, and Shuanghu Wang

–mass spectrometry (GC–MS) to evaluate effect of activated carbon on methomyl poisoning rats. Experimental Instrumentation and Conditions Agilent 6890N-5975B GC/MS with HP-5MS (0.25 mm × 30 m × 0.25 mm) was purchased

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Abstract  

Physical deterioration is a natural consequence of moisture attack in finished concrete. Moisture is retained in open voids in prepared cement during mixing and hydration stages. Further atmospheric moisture uptake occurs following dehydration under use conditions in polymer-containing cement formulations, since polymers act as conduits for moisture ingress. The initial attribute of added strength from the polymer in improved cement formulations is thus nullified. Customary solution to the moisture problem has centered around improving moisture resistance by significant reduction of inherent macro defects. A more complete method of moisture blocking by the reaction of activated carbon with a vinyl polymer included in the cement formulation is described here. The moisture blocking action is due to the mitigation of open voids by the occlusion of a carbon-vinyl additive, essentially resulting in filled voids or no voids in the prepared cement, producing a durable finished concrete product. Supporting evidence for the above by thermal, polarization, X-ray and SEM are reported in this paper.

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Introduction Activated carbons (AC) are most often produced from natural feedstocks, such as hard coal, lignite, wood, peat, stones, and peels of the fruits [ 1 – 3 ]. Based on the literature data, a conclusion can be drawn

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the behaviour of the mixture in relation to the mass of activated carbon. Experimental Textural and chemical characterization of activated carbon The carbonaceous samples measuring about 0.100 g are

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solid is known, which for this work is the activated carbon, this enthalpy is related to the volume of the micropore, W o , and to the molar volume, V m , of the adsorbate, by means of the Stoeckli and Kraehenbuehl equation [ 9 ]: (2) This

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