Factors controling the SO2 removal by porous carbons:: relevance of the SO2 oxidation step
Factors controling the SO2 removal by porous carbons:: relevance of the SO2 oxidation step
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DOI：
10.1016/s0008-6223(99)00109-8
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发表时间：
2000-01-01
期刊：
影响因子：
10.9
通讯作者：
Linares-Solano, A
中科院分区：
文献类型：
--
作者：
Raymundo-Piñero, E;Cazorla-Amorós, D;Linares-Solano, A
研究了具有不同表面化学性质和孔隙率的活性炭（AC）和活性炭纤维（ACF）在O-2存在下的SO2保留率。采用程序升温解吸（TPD）和H-2程序升温反应实验研究了样品的表面化学性质。采用CO2吸附等温线和N-2吸附等温线分别测定了273 K和77 K时的孔隙结构。在313 K的温度下，用2000 ppm SO2 （N-2）或2000 ppm SO2/5% O-2 （N-2）混合气体对新鲜样品和热处理样品（N-2 1173 K）进行了SO2吸附实验，结果表明，表面氧配合物的存在阻碍了SO2的吸附和氧化。此外，在热处理过程中，氧络合物的演化所产生的活性位点数量与吸附SO2的数量之间没有相关性。用微孔固体气体吸附的基本原理对所得结果进行了解释。将SO2氧化为SO3作为一个受孔径分布强烈影响的新变量，对SO2的吸收进行了分析。存在一个有利于SO2氧化为SO3的最佳孔径（即孔径约为7埃）。孔隙宽度的增大减少了SO2到SO3的转化，从而减少了碳样品中SO2的总量。(C) 2000 Elsevier Science Ltd.版权所有。
Activated carbons (AC) and activated carbon fibres (ACF) with different surface chemistry and porosity have been studied to analyse the SO2 retention in presence of O-2 at room temperature. Samples surface chemistry was studied using temperature programmed desorption (TPD) and H-2 temperature programmed reaction experiments. The porous texture was determined by CO2 and N-2 adsorption isotherms at 273 K and 77 K, respectively. SO2 adsorption experiments were performed at 313 K on fresh and heat treated (N-2 1173 K) samples using gas mixtures of 2000 ppm SO2 in N-2 or 2000 ppm SO2/5% O-2 in N-2 Adsorption experiments on heat treated samples show that the presence of surface oxygen complexes impedes the SO2 adsorption and its oxidation to SO3. Additionally, no correlation has been found between the: amount of SO2 adsorbed and the number of active sites created by the evolution of oxygen complexes during heat treatment. The results obtained have been explained using the fundamentals of gas adsorption for microporous solids. The SO2 uptake is analyzed considering the SO2 oxidation to SO3 as a new variable that is strongly affected by the pore size distribution. An optimum pore size exists (i.e. pore size of about 7 Angstrom) in which the oxidation of SO2 to SO3 is favoured. A pore width enlargement decreases the conversion of SO2 to SO3 and, thus, the total amount of SO2 retained by the carbon sample. (C) 2000 Elsevier Science Ltd. All rights reserved.