摘要
以棉秆为原料,以KOH为活化剂,制备了高比表面棉秆基生物质活性炭。分析了制得的活性炭的元素组成、表面官能团、吸附能力等物化性能,探讨了浸渍比,活化温度,活化时间等工艺参数对制备活性炭得率、表面官能团、碘值、亚甲基蓝值等性能的影响,并通过静态吸附实验比较了不同条件下制备活性炭对2,4-二硝基苯酚的吸附性能,探讨了典型炭样品对2,4-二硝基苯酚的等温吸附特性。结果表明,KOH活化棉秆基生物质活性炭的表面物化性质随浸渍比、活化温度等工艺参数变化而变化,活化适宜条件为浸渍比1∶3、活化温度800℃、活化时间90 min,在此条件下制得的炭样的碘值为1 251 mg/g,亚甲基蓝吸附值为478 mg/g,分别是国家一级品标准的1.25倍与3.54倍;对2,4-二硝基苯酚的Langmuir最大吸附量为747 mg/g,与Freundlich模型相比,Langmuir模型能较好地描述2,4-二硝基苯酚在炭样上的吸附行为,表明制备活性炭样品表面吸附位的能量分布较为均一。
High surface area biomass-based activated carbons were prepared from cotton stalk by KOH activation. The physical and chemical characteristics of prepared activated carbons such as elemental composition, surface functional groups and adsorption ability were evaluated. Effects of impregnation ratio, activation temperature and activation time on the yield, surface functional groups, iodine value and methylene blue value of activated carbons were studied. The adsorption capability for 2,4-dinitrophenol（DNP） on the prepared carbons under different processing parameters were discussed by a series of batch adsorption experiments. The adsorption characteristics for DNP on the representative carbons were also investigated. The results show that the physical and chemical characteristics of prepared activated carbons vary from different processing parameters such as impregnation ratio and activation temperature. The considerable preparation conditions are obtained as follows： impregnation ratio of 1：3, activation tempera- ture at 800℃ and activation time of 90 min. The iodine value and the methylene blue value of carbon prepared under above conditions reached 1 251 mg/g and 478 mg/g, which is 1.25 times and 3.54 times of the national first level for activated carbon, respectively. The Langmuir adsorption capacity for DNP on the prepared carbon is 747 mg/g. The adsorption behavior of DNP on the prepared carbon was found to fit better with Langmuir equation than the Freundlich equation, implying that the carbon sample has a homogeneous surface energy distribution.
出处
《环境工程学报》
CAS
CSCD
北大核心
2013年第12期4666-4672,共7页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(51102136)
国家大学生创新创业训练计划项目(121030779)
关键词
化学活化
工艺参数
2
4-二硝基苯酚
吸附
chemical activation
processing parameters
2,4-dinitrophenol
adsorption
