Thermal pretreatment of willow branches impacts yield and pore development of activated carbon in subsequent activation with ZnCl_(2) via modifying cellulose structure  

作　　者：Linghui Kong Chao Li Runxing Sun Shu Zhang Yi Wang Jun Xiang Song Hu Dong Wang Chuanjun Leng Xun Hu 

机构地区：[1]School of Material Science and Engineering,University of Jinan,Jinan 250022,China [2]Joint International Research Laboratory of Biomass Energy and Materials,College of Materials Science and Engineering,Nanjing Forestry University,Nanjing 210037,China [3]State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China [4]Shandong BASAN Graphite New Material Plant,Zibo 255311,China

出　　处：《Chinese Journal of Chemical Engineering》2024年第5期227-237,共11页中国化学工程学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(52276195);Program for Supporting Innovative Research from Jinan(202228072);Program of Agricultural Development from Shandong(SD2019NJ015)。

摘　　要：Development of pore structures of activated carbon(AC)from activation of biomass with ZnCl_(2) relies on content and structure of cellulose/hemicellulose in the feedstock.Thermal pretreatment of biomass could induce dehydration and/or aromatization to change the structure of cellulose/hemicellulose.This might interfere with evolution of structures of AC,which was investigated herein via thermal pretreatment of willow branch(WB)from 200 to 360℃and the subsequent activation with ZnCl_(2) at 550℃.The results showed that thermal pretreatment at 360℃(WB-360)could lead to substantial pyrolysis to form biochar,with a yield of 31.9%,accompanying with nearly complete destruction of cellulose crystals and remarkably enhanced aromatic degree.However,cellulose residual in WB-360 could still be activated to form AC-360 with specific surface area of 1837.9 m~2·g^(-1),which was lower than that in AC from activation of untreated WB(AC-blank,2077.8 m~2·g^(-1)).Nonetheless,the AC-200 from activation of WB-200 had more developed pores(2113.9 m~2·g^(-1))and superior capability for adsorption of phenol,due to increased permeability of ZnCl_(2) to the largely intact cellulose structure in WB-200.The thermal pretreatment did increase diameters of micropores of AC but reduced the overall yield of AC(26.8%for AC-blank versus 18.0%for AC-360),resulting from accelerated cracking but reduced intensity of condensation.In-situ infrared characterization of the activation showed that ZnCl_(2) mainly catalyzed dehydration,dehydrogenation,condensation,and aromatization but not cracking,suppressing the formation of derivatives of cellulose and lignin in bio-oil.The thermal pretreatment formed phenolic-OH and C=O with higher chemical innerness,which changed the reaction network in activation,shifting morphology of fibrous structures in AC-blank to“melting surface”in AC-200 or AC-280.

关 键 词：Thermal pretreatment Activation with ZnCl_(2) Willow branch Activated carbon Biochar 

分 类 号：TQ424.1[化学工程]