Klijanienko Aleksandra, Lorenc-Grabowska Ewa, Gryglewicz Grazyna
Wrocław University of Technology, Faculty of Chemistry, Department of Polymer and Carbonaceous Materials, Gdańska 7/9, 50-344 Wrocław, Poland.
Bioresour Technol. 2008 Oct;99(15):7208-14. doi: 10.1016/j.biortech.2007.12.059. Epub 2008 Feb 5.
Oak and birch were used as precursors to produce the activated carbons (ACs) with well-developed mesoporosity by phosphoric acid-promoted activation in a steam atmosphere. The effect of experimental variables such as the amount of activating agent, the soaking time and the type of wood on the development of porous structure upon heating at 480 degrees C was investigated. The materials were characterized by N2 adsorption at 77K, mercury porosimetry and elemental analysis. It was demonstrated that increasing impregnation ratio favors the development of micropores and small mesopores of 2-5nm, whereas the soaking time promotes the creation of large mesopores, between 10 and 50nm. Compared to birch, the oak activation using phosphoric acid in the same conditions gives ACs with lower mesopore volume and higher contribution of small mesopores that reflects the differences between both precursors in their biopolymer composition. The presence of steam in the H3PO4 activation process compared to nitrogen facilitates the development of mesoporosity to much higher extent for the birch than that of oak. The ACs prepared in this work show the BET surface area ranging from 800 to 2250m2g(-1), the total pore volume of 0.35-2.04cm3g(-1) with mesopore fraction between 0.06 and 0.68.
以橡木和桦木为前驱体，通过在蒸汽气氛中磷酸促进活化制备具有发达中孔结构的活性炭（ACs）。研究了活化剂用量、浸泡时间和木材类型等实验变量对480℃加热时多孔结构发展的影响。通过77K下的N2吸附、压汞法和元素分析对材料进行了表征。结果表明，增加浸渍比有利于2-5nm微孔和小中孔的发展，而浸泡时间则促进10-50nm大中孔的形成。与桦木相比，在相同条件下用磷酸活化橡木得到的ACs中孔体积较低，小中孔的贡献较高，这反映了两种前驱体生物聚合物组成的差异。与氮气相比，H3PO4活化过程中蒸汽的存在促进桦木中孔结构的发展程度远高于橡木。本工作制备的ACs的BET表面积为800-2250m2g(-1)，总孔体积为0.35-2.04cm3g(-1)，中孔分数为0.06-0.68。
