Textural and chemical characterizations of adsorbent prepared from palm shell by potassium hydroxide impregnation at different stages

被引:76
作者
Guo, J
Lua, AC
机构
[1] Univ Strathclyde, Dept Chem & Proc Engn, Glasgow G1 1XJ, Lanark, Scotland
[2] Nanyang Technol Univ, Sch Mech & Prod Engn, Singapore 639798, Singapore
关键词
KOH impregnation; microporousity; surface functional group; SO(2) removal; reaction mechanism;
D O I
10.1006/jcis.2002.8587
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Preparation and characterization of activated carbon from palm shell, a carbonaceous agricultural solid waste, by potassium hydroxide treatment at different stages were studied. The effects of activation temperature and chemical to sample ratio on the characteristics of the activated carbon were investigated. Fixed-bed adsorption of sulfur dioxide (SO(2)) gas was carried out to evaluate the adsorptive capacity of the samples. Desorption tests were conducted to verify the occurrence of chemisorption due to some surface functional groups or of chemical reaction between SO(2) and KOH. It was found that pre-impregnation of raw palm shell was involved in replacement of some hydrogen ions with potassium ions to form cross-linked complexes, which retarded the tar formation during carbonization, resulting in a relatively high yield. Moreover, these potassium ions accelerated the reaction as catalysts during gasification of chars by carbon dioxide. For chars with mid-impregnation, potassium hydroxide acted in two ways: (i) formation of metallic potassium by dehydration and (ii) conversion into potassium carbonate. Metallic potassium intercalated to the carbon matrix accounted for pore development and potassium carbonate layer prevented the sample from over burn-off. Post-impregnation of final products modified the textural characteristics of the sample as some pore entrances were blocked by chemicals. However, potassium hydroxide enhanced the amount Of SO(2) uptaken via formation of potassium sulfite. (C) 2002 Elsevier Science (USA).
引用
收藏
页码:227 / 233
页数:7
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