椰壳热解活化制备活性炭及其机理研究

利用热解活化法制备高吸附性能的椰壳活性炭并对其热解活化机理进行研究。结果表明,在热解活化温度为900℃,保温5 h,升温速率为10℃/min时,可以制备比表面积为1 047.65 m~2/g的椰壳活性炭,其中总孔容为0.51 cm~3/g,微孔孔容为0.44 cm~3/g。该活性炭的碘吸附值为1 302 mg/g,亚甲基蓝吸附值为195 mg/g。结果表明:在不添加任何活化气体或化学试剂的情况下,热解活化制备高吸附性能椰壳活性炭的机理可能是由于热解活化过程中,热解释放气体,造成一部分孔隙;高温下未炭化物芳构化形成石墨微晶,键断裂时释放部分气体;这些气体作为活化剂对椰壳原料进行了自活化,生成一定孔隙;在密闭的情况下,热解产生气体,使得反应器内产生微压力,对孔隙的形成有一定作用。

Study on Preparation and Mechanism of Activated Carbon from Coconut Shell by Method of Pyrolysis and Activation

Activated carbon with high adsorption properties were prepared from coconut shell by pyrolysis and activation,which the mechanism were investigated. The results showed that under the condition of pyrolysis and activation temperature at 900 ℃ for 5 hours with the heating rate 10 ℃/min,the prepared carbon had its surface area was 1047. 65 m2/g, with total pore volume of 0. 51 cm3/g and micropore volume of 0. 44 cm3/g,with the iodine adorption of 1302 mg/g and methylene blue adsorption of 195 mg/g. The mechanism of pyrolysis and activation for prepared activated carbon has some aspects without any gas or reagent. Some pore was produced from pyrolysis gas,which as activator was in the role of coconut shell. Under the high temperature uncarbonized material forming microcrystalline graphite,breaking bond when release gas. These gases act as activators to self activate the coconut shell material and produce a certain pore. In the airtight case,micro pressure was produced by pyrolysis gas in the reactor,which has a role to formation of the pore.