木质素对H_3PO_4法活性炭孔隙结构的影响

Influence of Lignin on the Pore Structure of Activated Carbon by H_3PO_4 Activation

以杨木、落叶松木、麻秆屑为原料,采用乙酸-亚氯酸钠法对原料进行脱木质素处理,研究木质素对H3PO4法活性炭孔隙结构的影响。通过物理吸附仪测定活性炭的比表面积和孔结构,利用碘值和亚甲基蓝吸附分析其吸附性能;采用TG/DTG分析原料去除木质素前后热解过程。结果表明,除去木质素后活性炭的比表面积、总孔容、外表面积变小;微孔孔容、微孔比表面积增加,木质素的去除有利于微孔的形成;碘吸附量增加,亚甲基蓝吸附量下降。除去木质素后的原料耐热性和热稳定性均下降。

Effect of lignin on the porous properties of activated carbon produced by H3PO4 activation has been investigated using sawdusts of poplar,larch and flax as starting materials.Lignin was removed by acetic acid-sodium chlorite method.The surface area and pore structure of obtained activated carbon were analyzed by H2-TPD.The adsorption properties were identified by iodine and methylene blue adsorption.Thermal behavior of the raw material was compared with the product after lignin removal by TG/DTG analysis.The results showed that with removal of lignin,the BET surface area,total pore volume and external surface area of activated carbon were decreased.Removal of lignin from wood materials was beneficial for the increment of micropore volume and surface area of micropore in activated carbon.The results of iodine and methylene blue adsorption were also demonstrated.Thermogravimetric results showed that the thermostability of raw material was decreased after removal of lignin.