CAJ | 학술논문

以纤维素为原料,通过在氮气氛下炭化和水蒸气活化得到纤维素基炭。采用热分析、傅里叶红外光谱、X 射线衍射及低温 N2吸附测试手段研究了纤维素的炭化和活化过程以及过程中炭微晶结构和比表面积的变化。纤维素分子结构中的C—OH、C—O—C、C—H 等基团在280~380℃之间大量分解,380℃后少量裂解产生的小分子碎片或基团持续分解,同时碳元素发生结构重排,形成石墨微晶。炭化温度是影响纤维素基活性炭微晶结构及孔结构的关键因素,随炭化温度的升高,石墨微晶尺寸变大,孔结构得到发育,但活性炭的比表面积则呈先增加后下降趋势,当炭化温度为600℃时所得活性炭比表面积最大；炭化时间对炭微晶结构及比表面积的影响不显著；随着活化时间的延长,先是炭结构中的非微晶碳被氧化,比表面积及总孔容积变大,然后微晶碳被氧化,微晶结构被破坏,炭中部分微孔变成中孔或大孔,导致比表面积及总孔容积变小,当微晶间的非微晶碳被充分氧化而又不破坏原微晶结构时得到的炭孔隙最丰富。
이섬유소위원료,통과재담기분하탄화화수증기활화득도섬유소기탄。채용열분석、부리협홍외광보、X 사선연사급저온 N2흡부측시수단연구료섬유소적탄화화활화과정이급과정중탄미정결구화비표면적적변화。섬유소분자결구중적C—OH、C—O—C、C—H 등기단재280~380℃지간대량분해,380℃후소량렬해산생적소분자쇄편혹기단지속분해,동시탄원소발생결구중배,형성석묵미정。탄화온도시영향섬유소기활성탄미정결구급공결구적관건인소,수탄화온도적승고,석묵미정척촌변대,공결구득도발육,단활성탄적비표면적칙정선증가후하강추세,당탄화온도위600℃시소득활성탄비표면적최대；탄화시간대탄미정결구급비표면적적영향불현저；수착활화시간적연장,선시탄결구중적비미정탄피양화,비표면적급총공용적변대,연후미정탄피양화,미정결구피파배,탄중부분미공변성중공혹대공,도치비표면적급총공용적변소,당미정간적비미정탄피충분양화이우불파배원미정결구시득도적탄공극최봉부。
Carbon samples were prepared from cellulose by carbonization under the nitrogen atmosphere and water steam activa-tion. Their structure and specific surface area during carbonation and activation processes were studied by thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction, and nitrogen adsorption at low temperature. The results show that groups in the cellulose molecular structure like C—OH, C—O—C and C—H are mostly pyrolyzed completely between 280 - 380 ℃ . A few frag-ments or surface groups produced during pyrolysis decompose continuously above 380 ℃ . Meanwhile, carbon atoms rearrange within the solid sample and form graphite crystallites. Carbonization temperature exerts a crucial influence on the microcrystalline carbon structure and pore structure. With the rise of carbonation temperature, the size of graphite crystallites increases and the pore structure develops, but the specific surface area of the carbon prepared first increases and then decreases, reaching maximum at 600 ℃ . Carbon-ization time has less significant influence on the structures. With increasing activation time, non-crystalline carbon is oxidized, the spe-cific surface area and total pore volume of the carbon sample increase simultaneously. However, a longer activation time causes that the original crystalline carbon structure is destroyed, the specific surface area and total pore volume of the carbon sample decrease. The po-rosity is mostly abundant when non-crystalline carbon is fully oxidized and the original crystalline carbon structure is not destroyed.