高温自生压活化制备高微孔率活性炭研究

Preparation of High Microporosity Activated Carbon by Autogenic Pressure under High Temperature

以椰壳、杏核、油茶壳和杉木屑为原料,不外加活化剂,采用高温自生压活化法制备微孔发达的活性炭,研究了反应条件对活性炭孔结构和吸附性能的影响。结果表明,以椰壳原料,在自生压力下选择活化温度900℃并保温6 h,制得的活性炭得率13.8%,微孔率达87.8%,比表面积1 194 m2/g、总孔容积0.528 cm3/g、碘吸附值1 280 mg/g和亚甲基蓝吸附值315 mg/g。自生压活化机理研究表明,木质原料热解产生的水蒸气和二氧化碳形成了良好的混合活化气氛,密闭反应器内产生的自生压力有效促进了气固活化反应的进行,明显提高微孔率。为活性炭生产提供了一种无污染,清洁方便,高得率的新型活化方法。

By using coconut shell, almond shell, camellia nutshell and Chinese fir sawdust as raw materials, high microporosity activated carbons were prepared via the activation method of autogenic pressure at elevated temperatures without activating agent, The effects of activation temperature, activation time and system pressure on the pore structure and adsorption properties of AC were studied. The results showed that coconut shell based AC was prepared with microporisty rate of 87.8%, and the yield was 13.8% under the autogenic pressure at elevated temperatures with activation 900℃C kept for 6 h. The surface area, total volume, iodine value, and methylene blue value were 1 194.4 m^2/g, 0. 528 cm^3/g, 1 280 mg/g, and 315 mg/g, respectively. Water vapour and carbon dioxide generated from pyrolysis of woody materials formed mixed activation agent, and the autogenous pressure effectively promote the activation reaction rate of gas and solid. The activation method of autogenic pressure at elevated temperatures was a kind of new activation method which had good economic and environmental benefits, since the production process could keep clean and convenient without any pollution and the yield of product was high.