摘要
以废弃生物质互花米草与棉秆为原料,采用KOH活化制备了高比表面积微孔生物质活性炭.研究了原料类别、浸渍比、炭化温度及保温时间对炭组成与吸附性能的影响,利用氮气吸附、X-射线衍射、红外光谱FT-IR、扫描电子显微镜SEM等技术对活性炭表面物化性质进行了分析,并通过BET方程、DFT密度函数理论及Horvath-Kawazoe方程对比表面积与孔分布进行了表征测定.结果表明,氢氧化钾活化制备互花米草与棉秆活性炭的适宜条件为浸渍比3:1、活化温度800℃、活化时间1.5 h.在此条件下制得的互花米草活性炭与棉秆活性炭的得率为16.36%和11.22%,BET比表面积高达2 825 m2.g-1和2 135 m2·g-1,孔容积分别为1.374 mg·g-1和1.038 cm3·g-1;孔径分布狭窄,95%的孔集中在3 nm以内.该条件下制备的互花米草与棉秆活性炭吸附性能好,对碘的吸附值分别为1 797 mg·g-1和1 251 mg·g-1,亚甲基蓝吸附值为495 mg·g-1和478mg·g-1,均超过了国家水处理用活性炭一级品标准;2种生物质炭样品对水中2,4-二硝基苯酚的Langmuir最大吸附量分别为932 mg.g-1、747 mg·g-1,均优于普通活性炭与活性炭纤维.
High surface area activated carbons were prepared with Spartina alterniflora and cotton stalk as raw materials and KOH as activating agent.Effects of materials type,impregnation ratio,activation temperature and heat preservation time on the yield,elemental composition and adsorptive capacity of activated carbon were studied.The properties and pore structure of the carbons were characterized with nitrogen adsorption,powder X-ray diffractometry（XRD）,infrared spectroscopy（FTIR） and scanning electron microscopy（SEM）.Main pore characteristics of activated carbons were analyzed by BET equation,Horvath-Kawazoe BET method and DFT method.The considerable preparation conditions are obtained as follows： impregnation ratio of 3∶1,an activation temperature of 800℃ and an activation time of 1.5 h.The BET surface area of activated carbon prepared from Spartina alterniflora reached 2 825 m2·g-1 when its total pore volume,yield,iodine number and methylene blue adsorption were 1.374 cm3·g-1,16.36%,1 797 mg·g-1 and 495 mg·g-1 respectively under above conditions.The activated carbon from cotton stalk was prepared with BET surface area of 2 135 m2·g-1,total pore volume of 1.038 cm3·g-1,yield of 11.22%,methylene blue adsorption of 1 251 mg·g-1,and iodine number of 478 mg·g-1,respectively.The methylene blue adsorption and iodine number are much higher than the national first level for activated carbon.The Langmuir maximum adsorption capacities of 2,4-dinitrophenol on the two carbons were 932 mg·g-1 and 747 mg·g-1,respectively,which are superior to ordinary activated carbon and activated carbon fiber.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2013年第1期328-335,共8页
Environmental Science
基金
国家自然科学基金项目(51102136)
教育部博士点基金项目(20110097120021)
关键词
生物质炭
氢氧化钾活化
高比表面积
表征
吸附
biomass-based carbon
KOH activation
high surface area
characterization
adsorption
