Adsorption and adsorbed species of SO2 during its oxidative removal over pitch-based activated carbon fibers
Adsorption and adsorbed species of SO2 during its oxidative removal over pitch-based activated carbon fibers
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DOI：
10.1021/ef980070f
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发表时间：
1999-02
期刊：
影响因子：
5.3
通讯作者：
I. Mochida;S. Miyamoto;Keiichi Kuroda;S. Kawano;S. Yatsunami;Y. Korai;A. Yasutake;M. Yoshikawa
中科院分区：
文献类型：
--
作者：
I. Mochida;S. Miyamoto;Keiichi Kuroda;S. Kawano;S. Yatsunami;Y. Korai;A. Yasutake;M. Yoshikawa
研究了沥青基活性炭纤维（ACF）氧化脱除湿空气中SO2过程中的吸附和吸附形态，以阐明其连续脱除SO2的反应机理、反应变量的影响以及惰性气氛下焙烧提高活性的原因。SO2吸附态的程序升温脱附结果表明，当同时存在氧和水时，ACF上的SO2吸附态主要为水合SO 3（H 2 SO 4），其在300 °C左右以SO 2的形式解吸，并且两者的存在通过氧化和水合吸附的SO 2而增加了物种的量，其在约60 °C下脱附而不氧化，在200 °C下脱附而氧化但不水合。通过平衡H2SO 4的洗脱和吸附，ACF对H2SO 4的吸附量在反应25 h后保持在同一水平，从而使SO2的去除稳定。在初始阶段，水的加入促进了ACF对SO2的吸附，但在稳态阶段，水的加入降低了ACF对H2SO 4的吸附量，使H2SO 4的洗脱速度快于SO2的吸附速度，从而使ACF在稳态时有更多的活性中心开放。因此，实现了完全切除。较高的煅烧温度显著增加了氧化和氧化/水合吸附的速率和量，解释了在1100 °C下煅烧的ACF的最大活性。OG-20 As在500-1000 °C下焙烧时吸附的SO2量和逸出的CO量具有良好的相关性，表明逸出的CO在ACF表面产生了吸附位点。不同比表面积、不同煅烧温度的活性炭纤维之间的关联式相似但不同。
Adsorption and adsorbed species of SO 2 in humid air during its oxidative removal were studied over pitch-based activated carbon fibers (ACFs) to clarify the reaction scheme of continuous removal of SO 2 , influence of reaction variables, and origin of activity enhancement by the calcination in inert atmosphere. The temperature-programmed desorption of SO 2 adsorbed species suggests that when both oxygen and water were present, the main species on ACF was hydrated SO 3 (H 2 SO 4 ), which desorbed in the form of SO 2 around 300 °C, and that the presence of both increased the amount of species by oxidizing and hydrating the adsorbed SO 2 , which desorbed around 60 °C without oxidation and 200 °C with oxidation but without hydration. The amount of adsorbed H 2 SO 4 over ACF stayed at the same level after 25 h of reaction by balancing elution and adsorption of H 2 SO 4 to allow the steady removal of SO 2 . More water enhanced the adsorption of SO 2 at the initial stage but reduced the amount of adsorbed H 2 SO 4 at the steady state, eluting out H 2 SO 4 faster than the adsorption of SO 2 to keep more active sites open over ACF at the steady state. Hence, complete removal was achieved. A higher calcination temperature significantly increased the rate and amount of both oxidative and oxidative/hydrating adsorption, explaining the largest activity of ACF calcined at 1100 °C. The amounts of adsorbed SO 2 and evolved CO from OG-20As by calcination at 500-1000 °C are well correlated, indicating that the evolved CO creates an adsorption site on the ACF surface. A similar but different correlation was obtained among ACFs of different surface areas calcined at different temperatures.